一.Influence of material properties on yield

1.Particle size composition

The particle size composition of the material is one of the key factors affecting the productivity of HF dewatering screens. When the material has a high content of fine particles, the productivity of the HF dewatering screen will usually be larger because the fine particles can pass through the screen holes more easily. Conversely, if the material has a high coarse grain content and exceeds the screen’s aperture range, these coarser materials take longer and require more vibratory energy to penetrate the screen, which results in a decrease in overall production. For example, in coal screening, if the content of fine coal with -0.5mm particle size in the raw coal accounts for a large proportion, the high frequency dewatering screen will be relatively easy to deal with, and the output can be maintained at a high level; and when the raw coal contains more lumps larger than the size of the screen holes, the screen machine needs to spend more time to crushing and screening of these large pieces of material, and the output will naturally be affected.

2.Humidity

The impact of material humidity on the output of high-frequency dewatering screen is more significant. In general, when the material humidity is large, the cohesion between the particles is enhanced, and it is easy to form agglomerates, resulting in poor material mobility, which in turn clogs the screen holes, reduces the screening efficiency, and the output decreases. However, the size of the screen mesh aperture will have a difference on the degree of influence of humidity. Usually, the larger the mesh size, the relatively smaller the impact of moisture. For wet materials with high moisture content, in order to improve the screening process, the mesh size can be increased or a wet screen can be used. Taking kaolin dewatering as an example, due to the high humidity and strong viscosity of kaolin, if ordinary screen and screening method is used, it is very easy to cause clogging of the screen holes, and the output is very low; while using larger aperture screen and combining with the wet sieving process, it can effectively reduce the material agglomeration, improve the screening efficiency, and increase the output.

3.Mud content

The mud content in the material is also a factor that can not be ignored. When the material contains a large amount of mud (general mud content greater than 8%), the mud will form a layer of sticky film on the screen surface, hindering the normal permeability of the material through the screen, seriously affecting the output of high frequency dewatering screen. At this time, wet screening is a more effective solution. Wet screening can use the flushing effect of the water flow, the mud and fine-grained materials together through the screen, reduce the mud attached to the screen surface, thus improving the output. In the process of gold mine tailings dewatering, if the mud content in the tailings is high, without wet screening, the tailings particles will be wrapped by the mud, difficult to pass through the screen, resulting in a significant reduction in the output of the dewatering screen; and after the adoption of the wet screening process, it can effectively separate the mud and tailings particles, and improve the dewatering efficiency of the tailings and the output.

4.Particle shape

The particle shape of the material will also have an impact on the output of high-frequency dewatering screen. Under normal circumstances, the vibrating screen mesh is mostly square. When the shape of the production material is irregular, bar-shaped or cylindrical, compared with spherical particles, these shapes of materials are more prone to clogging, thus affecting the production efficiency. For example, in the quartz sand screening process, if the quartz sand particles are irregularly shaped, with more long stripes or flaky particles, they will easily get stuck in the sieve holes during the screening process, preventing other materials from passing through and leading to a drop in production. For this situation, users can consider using new swing vibrating screen and other equipment more suitable for processing irregularly shaped materials to improve the output.

二.Influence of the equipment itself on the output

1.Effective screening area

Different high-frequency dewatering screen in the design and production of different parameters, including the effective screening area of the screen surface is an important parameter. Effective screening area refers to the ratio of the area of the sieve holes to the area of the entire screen surface, the higher the ratio, meaning that the amount of material that can pass through the screen in a unit of time is more, the higher the output. When choosing high-frequency dewatering screen, the equipment with large effective screening area should be chosen as much as possible to improve the production efficiency.

2.Screen size

Screen size is the mesh of the screen, which refers to the number of holes in the unit area. Generally speaking, the smaller the mesh of the screen, the larger the size of the screen, the faster the material passes through the screen, the higher the output. However, in actual production, the selection of screen size needs to consider the production requirements, not just for the pursuit of yield and ignore the screening accuracy.

3.Equipment structure design

Reasonable equipment structure design can improve the efficiency of the movement of materials on the screen surface, thus increasing the output. For example, some high-frequency dewatering screen adopts special screen surface structure, such as V-shaped screen surface design, this design can make the material form a certain climbing angle on the screen surface, increase the contact time between the material and the screen mesh and the probability of sieve through the screen, improve the effect of dewatering and screening, and then improve the output. At the same time, the feeding method and outlet design of the equipment will also affect the output. Uniform and stable feeding can ensure that the screen surface is uniformly stressed to avoid the accumulation of local materials affecting the screening efficiency; spacious and smooth outlet can reduce the residence time of the material in the sieve machine, accelerate the discharge speed of the material, and improve the output.

三.Influence of operating parameters on output

1.Motor power

As the power source of high-frequency dewatering sieve, vibrating motor is an indispensable part of the equipment. The size of the motor power directly affects the strength of the excitation force, and the excitation force is closely related to the production volume. In most cases, an appropriate increase in motor power can improve the excitation force, so that the vibration of the material on the screen surface is more intense, accelerating the stratification of the material and through the sieve, so as to achieve a higher production rate. However, it should be noted that the size of the high-frequency dewatering sieve and the motor power should be matched, excessive increase in excitation force will cause greater impact on the structure of the equipment, reducing the service life of the equipment.

2.Vibration frequency and amplitude

Vibration frequency and amplitude are important operating parameters of high-frequency dewatering screen, and they have a significant impact on the output. High-frequency dewatering screen adopts the mechanical characteristics of high frequency and high vibration intensity, which can destroy the tension on the surface of the slurry and the adsorption force of fine-grained materials on the screen surface, and accelerate the separation and permeability of materials. Through experimental research shows that, within a certain range, the appropriate increase in vibration frequency can increase the probability of less than the separation size of the material and sieve hole contact, thus improving the output. However, when the frequency is too high, the residence time of the material on the screen surface is too short, which may lead to part of the material not being able to be discharged through the screen, but reduce the output. Amplitude is the same, the appropriate amplitude can make the material in the screen surface fully jumping and tumbling, is conducive to through the screen; and amplitude is too large or too small are not conducive to the screening and dewatering of materials.

3.Equipment inclination

For square vibrating screen and other high-frequency dewatering screen with a certain inclination angle, the inclination of the equipment also has an impact on the output. The appropriate inclination can help the material on the screen surface natural decline, and at the same time with the help of vibration to achieve a better screening effect. If the inclination is too small, the material moves slower on the screen surface, which will affect the output; while the inclination is too large, the material may pass through the screen surface quickly, too late to fully screen, also leading to a reduction in output. Generally speaking, the inclination angle of the screen surface of high frequency dewatering screen is usually between – 3° ~ -5°, the specific value needs to be adjusted according to the nature of the material and production requirements. For example, when dealing with materials with good fluidity, the inclination can be appropriately reduced to prolong the residence time of the material on the screen surface and improve the screening accuracy and yield; while for the viscous material with poor fluidity, the inclination can be appropriately increased to promote the movement of the material.

The high and low output of high frequency dewatering screen is affected by the comprehensive impact of various factors. In actual production, these factors need to be comprehensively analysed and reasonably controlled, through the optimization of material pre-treatment, selection of suitable equipment and operating parameters, to improve the output and production efficiency of high frequency dewatering screen, to create greater economic benefits for the enterprise.

The post High-frequency dewatering screen output high and low affected by what factors appeared first on JDminingseparation.

一.The influence factors of linear vibrating screen amplitude

1.Vibration motor parameters

vibration motor is the core component of linear vibrating screen vibration, and its excitation force size, speed and other parameters directly affect the amplitude of linear vibrating screen. The larger the excitation force, the larger the amplitude of the linear vibrating screen under the same conditions; motor speed is also related to the amplitude of the existence of a certain correlation, usually changes in speed will change the vibration frequency, which affects the movement of the material on the screen surface and the performance of the amplitude.

2.Counterweight configuration

The counterweight on the vibration motor is an important means of adjusting the amplitude. By changing the number, weight and installation position of the counterweight block, the vibration motor can be adjusted to the size and direction of the vibration force, so as to achieve the adjustment of the amplitude of the linear vibrating screen. The unreasonable configuration of the counterweight block will lead to unstable amplitude or can not reach the expected value.

3.Screen structure and material

The overall structural design of the linear vibrating screen, the screen frame material and the stiffness of the support spring and other factors will also have an impact on the amplitude. Solid and stable structure and appropriate stiffness of the support spring can ensure the effective transmission of vibration energy, help to maintain a stable amplitude; while the poor material or structural design of the irrational sieve machine, in the vibration process there may be excessive energy loss and other problems, affecting the amplitude size and stability.

4.The nature of the material

screened material particle size, humidity, density, viscosity and other properties are different, the required optimal amplitude is also different. For example, for smaller particle size, humidity or viscous materials, usually need a smaller amplitude to avoid material blockage sieve holes; for larger particle size, density of materials, may need a larger amplitude to promote the movement of the material and screening.

二.The adjustment method of linear vibrating screen amplitude size

1.Through the vibration motor counterweight block adjustment

Determine the direction of adjustment: before adjusting, you need to observe the screening effect of the linear vibrating screen, and judge whether you need to increase or reduce the amplitude. If the material on the screen surface movement speed is too slow, screening efficiency is low, you may need to increase the amplitude; if the material jumping is too violent, or even part of the material jumps out of the screen surface, you may need to reduce the amplitude. Adjust the number of counterweights: increasing the number of counterweights can increase the vibrating force of the vibrating motor, thus increasing the amplitude of the linear vibrating screen; decreasing the number of counterweights will reduce the vibrating force and amplitude. When increasing or decreasing the number of counterweights, it is necessary to pay attention to keeping the number and weight of counterweights on both sides of the vibrating motor symmetrical, in order to avoid the imbalance that leads to abnormal vibration of the equipment, noise and damage. Changing the position of the counterweight block: besides adjusting the quantity, the amplitude can also be adjusted by changing the installation position of the counterweight block on the eccentric block of the vibration motor. Generally speaking, moving the counterweight block away from the centre of the vibration motor shaft can increase the eccentric distance, thus increasing the excitation force and amplitude; on the contrary, moving the counterweight block closer to the centre of the shaft will reduce the amplitude. When adjusting the position, the same should be ensured that both sides are adjusted symmetrically. Gradual fine-tuning: in the process of adjusting the counterweight block, don’t make a one-time large-scale adjustment, should gradually increase or decrease the number of counterweight block, change the position, start the equipment to observe the screening effect and amplitude change after each adjustment, and then make the next adjustment according to the actual situation until reaching the suitable amplitude.

2.Adjust the speed of the vibration motor

Choose a suitable speed regulation: some linear vibrating screens are equipped with adjustable speed vibration motors, and the common speed regulation methods include frequency conversion, electromagnetic speed regulation, etc. The frequency conversion is achieved by changing the power supply, and the speed of the vibration motor is adjusted by changing the power supply. Frequency conversion speed regulation is to adjust the motor speed by changing the power supply frequency, which has the advantages of wide speed range, high precision, energy saving, etc. Electromagnetic speed regulation is to use electromagnetic clutch to achieve speed regulation. Adjusting the speed slowly: when adjusting the speed, it should be done slowly to avoid the impact on the equipment caused by the sudden change of the speed. Gradually increase or decrease the rotational speed, and at the same time observe the amplitude change of the linear vibrating screen and the material screening situation. Generally speaking, increasing the rotational speed will increase the vibration frequency and may increase the amplitude to a certain extent, but the specific effect should be determined according to the actual situation of the equipment and materials; reducing the rotational speed may reduce the amplitude. Comprehensive consideration of other factors: when adjusting the rotational speed, not only should we pay attention to the change of amplitude, but also consider the trajectory of the material on the screen surface, screening efficiency and other factors. If the rotational speed is too high, although the amplitude may increase, but the residence time of the material on the screen surface is too short, which is not conducive to the stratification and permeability screening; too low a rotational speed may lead to insufficient movement of the material, affecting the screening effect.

3.Replacement of the support spring

Assessment of the spring state: the support spring may be fatigued, deformed, elasticity weakened and other problems after long-term use, affecting the amplitude stability of the linear vibrating screen. If the amplitude of the screen machine is found to be unstable or abnormal, it is necessary to check the state of the support spring and judge whether it needs to be replaced. Choose the right spring: when replacing the support spring, choose a spring that matches the specifications, material and stiffness of the original spring. The stiffness of the spring has a direct effect on the amplitude. A spring with greater stiffness provides more stable support and helps to maintain a larger amplitude, while a spring with less stiffness may reduce the amplitude. When selecting springs, the overall structure and design requirements of the equipment should also be considered. Install the springs correctly: when installing the support springs, make sure that the springs are installed in the exact position and the force is uniform. Improper installation may lead to vibration imbalance of the screen machine, affecting the amplitude and normal operation of the equipment. After installation, the screen machine should be debugged to check whether the amplitude reaches the expected effect.

三.The attention of adjusting the amplitude

1.Equipment protection

Avoid over-adjustment: when adjusting the amplitude, avoid excessive increase in the counterweight block or over-adjustment of the vibration motor speed, so as not to make the equipment to withstand excessive loads, resulting in overheating of the vibration motor, deformation of the sieve frame, damage to the support springs and other problems, which will Shorten the service life of the equipment. After each adjustment, observe the running status of each part of the equipment to ensure that the equipment is normal. Regular inspection and maintenance: after adjusting the amplitude, the linear vibrating screen should be comprehensively inspected, including whether the wiring of the vibrating motor is loose, whether the connecting parts of the screen frame are firm, and whether the support spring is abnormal. At the same time, in accordance with the maintenance requirements of the equipment, lubrication, cleaning and other maintenance work on a regular basis to ensure that the equipment is in good operating condition. Record the adjustment: Make detailed records of the process and results of each amplitude adjustment, including the time and method of adjustment, the size of the amplitude before and after the adjustment, and information on the operating condition of the equipment. These records help to analyse the subsequent operation of the equipment, sum up the adjustment experience, for future equipment maintenance and adjustment to provide reference.

2.Production Adaptation

Consideration of material characteristics: As mentioned above, different materials have different properties, when adjusting the amplitude, we should fully consider the material’s particle size, humidity, density, viscosity and other factors, and choose the appropriate amplitude according to the characteristics of the material. In the replacement of screening materials, also need to re-evaluate and adjust the amplitude, in order to ensure the best screening effect. Observe the production effect: after adjusting the amplitude, we should continuously observe the movement state of the material on the screen surface and the screening effect, including the stratification of the material, the permeability rate, the processing capacity and other indicators. If the screening effect is found to be unsatisfactory, it is necessary to analyse the reasons in time, further adjust the amplitude or check whether there are problems in other aspects of the equipment. with the production process: the screening process of the linear vibrating screen is usually a part of the whole production process, and when adjusting the amplitude, it is necessary to consider the cooperation with other production equipment and process links. For example, to ensure that the particle size of the screened material meets the requirements of the subsequent production process, to avoid improper adjustment of the amplitude to affect the smooth progress of the entire production process.

The post How to adjust the amplitude size of linear vibrating screen? Precautions for adjusting the amplitude appeared first on JDminingseparation.

一.The material properties: the basic basis for selection

The material properties are the primary considerations of the vibrating screen type, covering the physical and chemical properties of the material, such as humidity, temperature, viscosity, corrosiveness, etc. These characteristics directly determine the vibrating screen material, structure and the choice of working mode.

1.Humidity

The humidity of the material has a significant impact on the screening process. Moist materials are easy to agglomerate, blocking the sieve holes, reducing the screening efficiency. For materials with low moisture content, conventional vibrating screens can meet the screening requirements. For example, in the grain processing industry, wheat, corn and other grains with low water content, the use of linear vibrating screen can achieve high efficiency screening. Linear vibrating screen through the vibration motor generated by the linear vibration, so that the material in the screen surface to do linear motion, complete screening. However, when the material has high humidity, a specially designed vibrating screen is required. For example, in the coal washing industry, the moisture content of the raw coal is sometimes as high as 20% – 30%, then the use of relaxation screen. The screen surface of the relaxation sieve is composed of fixed screen frame and movable screen frame, movable screen frame under the action of vibration force to do high-frequency elastic deformation, so that the wet, viscous materials in the screen surface to produce a strong jumping and tumbling, and effectively prevent the sieve holes from clogging, improve the screening efficiency.

2.Temperature

High temperature materials put forward higher requirements on the material and structure of vibrating screen. If the material temperature is too high, the screen mesh and screen frame made of ordinary materials may be deformed and damaged due to high temperature, affecting the normal operation of the equipment. For materials with a temperature of 100℃ – 300℃, the vibrating screen can be made of high-temperature resistant stainless steel, such as 310S stainless steel, which has good high-temperature strength and oxidation resistance. For example, in the process of cement production, the high temperature cement clinker out of the kiln needs to be cooled down by the cooling equipment first, and then use the high temperature stainless steel circular vibrating screen for screening to ensure the stable operation of the equipment. For materials with higher temperature, in addition to the selection of special high-temperature resistant materials, it is also necessary to carry out cooling design for vibrating screen. Such as in the metallurgical industry, high temperature sintered ore screening, vibrating screen frame and screen mesh can be set at the water-cooled or air-cooled device to reduce the temperature of the equipment, to extend the service life.

3.Viscosity

Viscous materials are very easy to adhere to the screen surface in the screening process, resulting in clogging of the screen holes and affecting the screening effect. For less viscous materials, by increasing the vibration frequency and amplitude of the vibrating screen, the material moves quickly on the screen surface to reduce adhesion. For example, in the food processing industry, the lower viscosity of sugar powder screening, can be used rotary vibration sieve, its unique three-dimensional vibration mode, so that the material on the screen surface to do complex three-dimensional movement, effectively preventing material adhesion. For materials with higher viscosity, such as bentonite and clay, special anti-adhesion designs are required. For example, the use of ultrasonic vibrating screen, the equipment in the screen mesh attached ultrasonic vibration system, generating high-frequency vibration, so that the material on the screen surface in a suspended state, to avoid adhesion, and at the same time to improve the screening accuracy of fine-grained materials.

4.Corrosive

materials with corrosive properties, such as acid and alkali solutions in the chemical industry, salts, etc., will cause corrosion on the material of the vibrating screen. In order to prevent the equipment from being corroded, the vibrating screen made of corrosion-resistant materials should be selected. For acidic materials, the vibrating screen can be made of polypropylene, polyvinylidene fluoride and other plastic materials or titanium alloy materials; for alkaline materials, stainless steel materials can be used, such as 316L stainless steel, which has good alkali resistance and corrosion resistance.

二.The material particle size: the key parameter to determine the screening equipment

The material particle size refers to the size of the material particles, which directly determines the number of screen mesh of the vibrating screen, the number of screen layers, and the choice of equipment type.

1.Determination of screen mesh

Screen mesh refers to the number of holes on the screen per inch, the larger the mesh, the smaller the holes are, and the finer the sieve size. In the selection, according to the particle size distribution of the material and screening requirements to determine the appropriate screen mesh. For example, in the paint production industry, if you want to sieve the paint raw materials to 100 – 200 mesh, you need to choose the appropriate mesh screen. For the screening of coarse-grained materials, such as stone grading in the mining industry, a lower mesh size is generally used, e.g. 10 – 50 mesh.

2.Selection of Screening Layers

According to the complexity of material particle size and screening requirements, different layers of vibrating screen can be selected. Single layer vibrating screen is suitable for simple particle size classification, such as the material is divided into qualified and unqualified particle size. For example, in the sand and gravel production line, a single layer of circular vibrating screen is used for the initial screening of the stone material, and the stone material larger than the specified particle size is screened out. Multi-layer vibrating screens can achieve finer grading, generally with 2 – 5 layers of screens, up to 7 layers. For example, in the quartz sand processing industry, the use of three-deck vibrating screen can be divided into four grades of coarse sand, medium sand, fine sand and ultra-fine sand, to meet the needs of different industrial fields.

3.Matching of equipment type and particle size

Different types of vibrating screens are suitable for screening materials with different particle size ranges. For coarse-grained materials (particle size greater than 10mm), such as mining ore, construction waste, etc., circular vibrating screen and linear vibrating screen are commonly used equipment. Circular vibrating screen through the centrifugal force generated by the eccentric block to make the screen box do circular vibration, with a large handling capacity, high screening efficiency; linear vibrating screen is suitable for granular, powdery materials screening and grading, screening precision is high.

三.The shape of the material: an important factor affecting the screening effect

The shape of the material is varied, and the behaviour of different shapes of materials in the screening process varies greatly, so the impact of the shape of the material needs to be fully considered in the selection.

1.Spherical and cubic materials

Spherical and cubic materials have better fluidity, easy to pass through the sieve holes on the screen surface, and screening is relatively easy. For such materials, conventional vibrating screen can be used, such as linear vibrating screen, circular vibrating screen and so on. For example, in the ceramic industry, the screening of spherical ceramic raw material particles, the use of linear vibrating screen can achieve high efficiency screening, and high screening accuracy.

2.Flaky and Needle-like Materials

The shape of flaky and needle-like materials is irregular, and they are easy to get stuck in the sieve holes during the screening process, resulting in clogging of the sieve holes and reducing the screening efficiency. For this kind of material, should be used with a special structure of the vibrating screen. For example, the vibrating screen with square holes can reduce the jamming phenomenon of flaky and needle-like materials. In addition, a vibrating screen with a large screen surface inclination can also be selected, so that the material moves quickly on the screen surface, reducing the possibility of blockage. In the metal processing industry, the flaky metal chips for screening, you can use square holes of the linear vibrating screen, and appropriately increase the angle of inclination of the screen surface to improve the screening effect.

3.Fibrous materials

Fibrous materials are flexible and entangled, easily entangled with each other to form a ball, which is difficult to pass through the screen holes. For the screening of fibrous materials, can choose to have a vibrating screen with the function of dispersing. For example, in the paper industry, the fibrous pulp screening, can use high-frequency vibrating screen, its high-frequency vibration can effectively break up the fibre mass, so that the fibre passes through the sieve hole smoothly. At the same time, a comb tooth structure can also be set on the screen surface to further comb the fibres and prevent entanglement.

四.Tthe material application industry: fit the industry demand selection direction

1.Mining industry

Mining industry is mainly for ore crushing, screening and grading, processing a large amount of material, a wide range of particle size, from coarse-grained raw ore to fine-grained concentrate powder need to be screened. In this industry, circular vibrating screen and linear vibrating screen are widely used. Circular vibrating screen is commonly used in the primary screening of raw ore and screening after crushing, large capacity, can adapt to the harsh working environment; linear vibrating screen is commonly used in the screening and dewatering of fine-grained materials, such as the screening and dewatering of concentrate powder.

2.Food industry

The food industry has very high hygienic requirements for material screening, and the equipment must meet the food hygiene standards and not cause pollution to the materials. Therefore, in this industry, mostly use stainless steel vibrating screen. These vibrating screens have a compact structure, good sealing, easy to clean and other characteristics, which can effectively prevent the material from being contaminated in the screening process.

3.Chemical industry

The chemical industry has a wide variety of materials with complex properties, some of which are corrosive, toxic or flammable and explosive. Therefore, the chemical industry has strict requirements on the material, sealing and explosion-proof performance of vibrating screen. For corrosive materials, need to choose corrosion-resistant material vibrating screen; for toxic or flammable and explosive materials, should be selected with good sealing, explosion-proof function of the vibrating screen.

4.Building materials industry

Building materials industry such as cement, sand and gravel production process, the material handling capacity is large, the vibrating screen wear resistance and reliability requirements are high. In this industry, circular vibrating screen and linear vibrating screen are commonly used equipment. In order to improve the wear resistance of the equipment, the screen mesh and screen frame can be made of wear-resistant materials, such as manganese steel.

五.Purpose of material screening: clear selection of the core requirements

1.Classification

Material classification is to classify the material into different grades according to the size of the particle, in order to meet different production requirements. For materials with high grading requirements, such as chemical raw materials, food additives, etc., multi-layer vibrating screen or high-precision ultrasonic vibrating screen can be used to achieve fine grading.

2.De-immersion

De-immersion is to remove the impurities in the material and improve the purity of the material. For materials with higher requirements for removing impurities, such as grain, tea, etc., vibrating screen with high efficient function of removing impurities can be used.

3.Dewatering

Dewatering is to remove the water in the material to make the material reach the specified moisture content. In mining, coal and other industries, it is often necessary to dewater materials. For the dehydration operation, linear vibrating screen or dewatering screen can be used.

To sum up, the selection of vibrating screen is a process of comprehensive consideration of material properties, material particle size, material shape, material application industry and material screening purpose. Only by deeply understanding the material characteristics and production needs, combined with the characteristics of different types of vibrating screens, can we choose the most suitable vibrating screen equipment, achieve efficient and accurate material screening, and improve the economic and social benefits of industrial production. In the actual selection process, you can also consult with professional vibrating screen manufacturers to obtain more detailed and accurate selection recommendations to ensure the scientific and reasonable selection programme.

The post How to choose vibrating screen according to the material? Five selection points appeared first on JDminingseparation.

一.The influence of the adjustment of the flotation machine inflatable amount on the flotation effect

1.The relationship between the inflatable amount and bubble generation

In the flotation process, the inflatable amount is the key factor affecting the generation of bubbles. The right amount of air filling can make the flotation machine produce suitable size and sufficient number of bubbles. When the air is pressed into the flotation machine, under the action of the stirring mechanism, the air is dispersed into tiny bubbles, which constitute the carrier for the attachment of mineral particles. If the inflatable amount is insufficient, the number of bubbles is small and the diameter is large, resulting in a decrease in the probability of collision contact between the bubbles and the mineral particles, it is difficult to effectively achieve the separation of the flotation of minerals; while the inflatable amount is too large, the bubbles are too dense, easy to merge the phenomenon of the formation of larger bubbles, which is also unfavourable to the attachment of mineral particles.

2.The effect on mineral attachment and sorting

Suitable inflation volume helps to improve the attachment efficiency of mineral particles and bubbles. In the process of rising bubbles, hydrophobic mineral particles will selectively attached to the surface of the bubble, with the bubble floating to the surface of the slurry to form a foam layer. When the inflation volume is in the optimal range, the bubble rising speed is moderate, and there is enough contact time and space with the mineral particles, which can make more target minerals attached to the bubble, thus improving the flotation recovery rate. For example, when treating copper sulfide ores, an appropriate increase in the inflation volume can significantly improve the flotation recovery rate of copper minerals. However, when the inflation volume is too large, the violent movement of the bubbles may cause the mineral particles already attached to the bubbles to fall off, and also cause the instability of the liquid level of the slurry, which affects the effect of scraping the bubbles; and when the inflation volume is too small, it cannot carry enough mineral particles to the liquid level, which reduces the flotation efficiency.

3.Adjustment methods and optimisation strategies

The adjustment of the inflation volume is usually achieved by adjusting the air volume of the blower or the valve opening on the flotation machine inlet pipeline. In actual production, it needs to be adjusted comprehensively according to the nature of minerals, pulp concentration, flotation machine type and other factors. Before the start of the flotation operation, a small test should be carried out to determine the optimal range of inflation volume for different minerals under different working conditions. In the production process, the bubble status and flotation indexes in the flotation machine should be monitored in real time, and if the flotation effect is found to be poor, the filling volume should be fine-tuned in time. In addition, regularly check the operating conditions of the filling equipment to ensure its stable gas supply, to avoid fluctuations in the filling volume due to equipment failure.

二.The influence of the area of the flotation circulation hole on the effect of flotation

1.The relationship between the area of the circulation hole and the pulp circulation.

Flotation circulation hole is an important channel for pulp circulation inside the flotation machine, and the size of its area directly affects the circulation volume and circulation speed of the pulp. When the circulation hole area is large, the slurry circulation increases, and the flow speed of the slurry in the flotation machine is accelerated, which helps to make the mineral particles and bubbles, pharmaceuticals fully mixed, and promotes the collision and adhesion of mineral particles and bubbles. However, if the circulation hole area is too large, the slurry circulation speed is too fast, which will lead to the shortening of the residence time of the slurry in the flotation machine, and some mineral particles may be discharged from the flotation machine before fully contacting the bubbles, which affects the flotation effect; on the contrary, if the circulation hole area is too small, the circulation volume of the slurry is insufficient, the slurry agitation is not sufficient, and the mineral particles are not uniformly mixed with the bubbles and the chemicals, which is also unfavourable to the flotation process.

2.The effect on the role of flotation chemicals and mineral sorting

Reasonable circulation hole area can ensure that the flotation chemicals are evenly dispersed in the slurry, giving full play to the role of the chemicals. For example, the foaming agent needs to be uniformly dispersed in the slurry in order to effectively reduce the surface tension of the bubbles and promote the generation and stability of the bubbles; the trapping agent also needs to be in full contact with the mineral particles in order to achieve selective adsorption of the target minerals. When the circulating hole area is appropriate, the good circulation of the slurry makes the agent can quickly spread to the whole flotation machine, and the mineral particles fully interact with each other, so as to improve the flotation efficiency. On the contrary, unreasonable circulation hole area will lead to uneven distribution of chemicals, some areas of chemicals concentration is too high, while some areas of chemicals concentration is too low, affecting the separation effect of minerals, reducing the flotation recovery rate and concentrate grade.

3.Adjustment methods and optimisation strategies

Adjusting the area of the flotation circulation holes is generally achieved by changing the number and size of the circulation holes or using an adjustable circulation hole device. When installing the flotation machine, the appropriate initial setting of circulating holes should be selected according to the characteristics of the mineral particle size composition, density, floatability, etc. The circulating hole area should be adjusted according to the change of flotation indexes during the production process. In the production process, the circulation hole area is adjusted according to the changes in flotation indexes. If the mineral sorting effect is found to be poor, the slurry circulation can be optimised by appropriately increasing or decreasing the area of the circulation hole. At the same time, the circulation hole is cleaned regularly to prevent debris in the slurry from blocking the circulation hole and affecting the effect of slurry circulation.

三.The influence of flotation machine stirring mechanism clearance on the flotation effect

1.The relationship between the stirring mechanism clearance and the stirring intensity

The main role of the flotation machine stirring mechanism is to make the slurry, air and chemicals fully mixed, and to disperse the air into tiny bubbles. Stirring mechanism gap refers to the distance between the stirring impeller and stator, tank body and other components, which directly affects the stirring intensity. When the mixing mechanism gap is small, the mixing impeller in the process of rotation on the slurry shear effect to enhance the mixing intensity increases, can be more effective in the air dispersed into tiny bubbles, while the slurry in the mineral particles, chemicals and bubbles are fully mixed. However, too much stirring intensity will also bring some problems, such as increasing energy consumption, aggravate the wear and tear of equipment, and may make the mineral particles already attached to the bubble due to the strong stirring effect and fall off; stirring mechanism gap is too large, the stirring impeller on the slurry weakened, the stirring intensity is insufficient, the air dispersion effect is poor, the diameter of bubbles is large, the slurry mixing is not uniform, is not conducive to the conduct of the flotation process.

2.The effect on bubble dispersion and mineral sorting

The appropriate gap of the stirring mechanism can ensure good bubble dispersion effect and mineral sorting effect. In the appropriate gap, the stirring impeller can disperse the air into uniform, small bubbles, these bubbles have a large specific surface area, which can provide more attachment sites for the mineral particles, and improve the probability of attachment of minerals and bubbles. At the same time, sufficient agitation keeps the mineral particles in suspension in the slurry, increasing the chances of collision between the mineral particles and the bubbles, thus improving the flotation recovery rate and concentrate grade. If the gap of the stirring mechanism is not suitable, whether too large or too small, it will lead to uneven dispersion of bubbles, and the contact and attachment of mineral particles with bubbles will be affected, thus reducing the flotation effect.

3.Adjustment methods and optimisation strategies

Adjusting the gap of the mixing mechanism needs to be carried out under the shutdown state of the flotation machine. Usually, the gap size can be changed by adjusting the installation position of the mixing impeller or replacing gaskets of different specifications. At the stage of equipment installation and commissioning, the mixing mechanism gap should be set in strict accordance with the requirements of the equipment manual, and trial operation should be carried out to observe the mixing effect and flotation indexes. During long-term operation, the mixing mechanism gap may change due to the wear and tear of the equipment, etc. Therefore, it is necessary to check the gap size regularly, and make timely adjustments when the gap is found to be out of the reasonable range. In addition, choosing good quality and wear-resistant mixing parts also helps to maintain the stability of the mixing mechanism gap and prolong the service life of the equipment.

四.The influence of flotation machine scraping foam and liquid level adjustment on the flotation effect

1.The relationship between scraping speed and foam layer stability

Scraping foam is to scrape the foam layer formed in the flotation machine, to achieve the separation of useful minerals and slurry is an important link. Scraping speed has a significant impact on the stability of the foam layer. If the scraping speed is too fast, it will destroy the structure of the foam layer, resulting in the mineral particles in the foam layer can not be scraped out in time to fall back into the slurry, reducing the recovery rate of flotation; at the same time, too fast scraping speed may also bring part of the slurry into the foam product, affecting the grade of the concentrate. While scraping bubble speed is too slow, the foam layer will accumulate too thick in the flotation machine, the water in the foam layer is difficult to discharge, will also reduce the concentrate grade, and may lead to foam overflow to the non-scraping bubble area, affecting the normal conduct of the flotation process.

2.The effect of liquid level on mineral sorting

The liquid level of the flotation machine directly affects the flotation of mineral particles and the effect of scraping bubbles. The appropriate liquid level can ensure that the foam layer has enough space to form and stable existence, so that the mineral particles attached to the bubble smoothly float to the liquid surface and be scraped out. When the liquid level is too high, the foam layer becomes thin, easy to rupture, part of the mineral particles will return to the slurry with the rupture of the foam layer, reducing the flotation recovery; when the liquid level is too low, it is difficult to form a stable structure of the foam layer, and it may lead to insufficient scraping, which also affects the flotation effect. In addition, the liquid level also affects the residence time of the slurry in the flotation machine, which in turn affects the separation of minerals.

3.Adjustment methods and optimisation strategies

The adjustment of scraping speed is usually achieved by changing the rotational speed of the scraping motor or the transmission ratio of the transmission device. In actual production, according to the thickness of the foam layer, the nature of minerals and flotation indexes and other factors to determine the appropriate scraping speed. The approximate range of bubble scraping speed can be determined through a small test, and then fine-tuned according to the actual situation in the production process. For the adjustment of the liquid level, it is generally achieved by adjusting the opening of the tailings discharge valve of the flotation machine. When it is necessary to increase the liquid level, reduce the opening of the tailings discharge valve, so that the slurry accumulates in the flotation machine; when it is necessary to reduce the liquid level, increase the opening of the tailings discharge valve to accelerate the discharge of the slurry. When adjusting the liquid level, pay attention to the changes in the foam layer and flotation indexes, to avoid improper adjustment of the liquid level affecting the flotation effect. At the same time, regularly check the operating conditions of the bubble scraping device and liquid level detection device to ensure their normal operation.

In summary, the adjustment of the flotation machine inflatable volume, the control of the flotation circulation hole area, the setting of the gap of the stirring mechanism, and the scraping bubble and liquid level adjustment are four operations that have an important and complex impact on the flotation effect. In actual industrial production, the operator needs to fully understand the intrinsic connection between these operating factors and the flotation effect, and according to different mineral properties and production requirements, comprehensively use a variety of adjusting methods to accurately control the operating parameters of the flotation machine, in order to achieve the best flotation effect, and improve the production efficiency and economic benefits.

The post Analysis of the influence of four key operations on the flotation effect of flotation machine and optimisation strategy appeared first on JDminingseparation.

一. Equipment selection and installation optimization​

1.Scientific and reasonable equipment selection​

There are many types of vibrating feeders, and different models are suitable for different material characteristics and production requirements. When selecting, first of all, the physical properties of the material, such as particle size, humidity, density, and hardness, should be fully considered. For example, for materials with larger particle size and higher hardness, a heavy-duty vibrating feeder with strong load-bearing capacity and wear resistance should be selected; and for materials with higher humidity, it is necessary to consider its easy adhesion characteristics and select a feeder with an anti-sticking design to prevent material blockage and affect feeding efficiency. ​

Secondly, according to the production scale and production process requirements, accurately calculate the required feeding amount. Generally speaking, the rated feeding amount of the equipment should be slightly larger than the maximum feeding amount required for actual production to ensure that it can meet the demand during peak production. At the same time, it is necessary to combine other equipment parameters of the production line to ensure that the vibrating feeder and subsequent equipment (such as crushers, conveyors, etc.) match each other in production capacity to avoid inefficient production lines due to insufficient or excessive feeding of the feeder.​

2.Standardized and accurate equipment installation​

Correct installation is the basis for ensuring the normal operation and efficient production of the vibrating feeder. During the installation process, the operation must be carried out strictly in accordance with the requirements of the equipment installation manual. First, ensure that the foundation of the feeder is firm and reliable, and the flatness and levelness of the foundation must meet the standards, otherwise it will cause abnormal vibration and increased wear of components during the operation of the equipment. ​

Secondly, when installing the vibration motor, it is necessary to pay attention to the opposite direction of the two motors, and the magnitude of the exciting force should be reasonably adjusted according to the characteristics of the material and the feeding amount. If the exciting force is too large, the equipment will vibrate too violently, increase the wear and energy consumption of the equipment; if the exciting force is too small, the ideal feeding effect cannot be achieved. At the same time, it is necessary to ensure that the connection between the motor and the feeder is firm to avoid loosening during operation. ​

In addition, during the installation process, attention should also be paid to the connection between the feeder and the storage bin and the receiving device. There should be an appropriate distance and angle between the feeder and the discharge port of the storage bin to ensure that the material can flow out smoothly and prevent the material from causing excessive impact on the feeder; the docking with the receiving device should be accurate to ensure that the material can be accurately and smoothly transported to the next process to avoid material spillage and accumulation.

二. Operation and parameter adjustment

1.Standardized operation process

The operation level and standardization of the operator directly affect the production efficiency of the vibrating feeder. Before starting the equipment, the operator should conduct a comprehensive inspection of the equipment, including checking whether the connection of each component is firm, whether the wiring of the vibration motor is correct, whether the lubrication system is normal, etc. After confirming that there is no abnormality in the equipment, start the equipment in the prescribed order, start the vibration motor first, and then open the discharge gate of the storage bin after the equipment runs smoothly, and gradually increase the feeding amount.

During the operation of the equipment, the operator should pay close attention to the operating status of the equipment, and judge whether the equipment is operating normally by observing the feeding situation of the material, the vibration amplitude and sound of the equipment. If it is found that the material feeding is uneven, the equipment vibrates abnormally, or there is an abnormal sound, the machine should be stopped in time for inspection and troubleshooting. At the same time, according to production needs and material characteristics, the feeding amount should be adjusted in time to avoid excessive or insufficient feeding affecting production efficiency.

When the equipment is shut down, it should also be operated in the prescribed order. First close the discharge gate of the storage bin, and then stop the vibration motor after all the materials on the feeder have been transported. After shutdown, the equipment should be cleaned and maintained to prepare for the next startup. ​

2.Optimization and adjustment of key parameters ​

Vibration frequency and amplitude: Vibration frequency and amplitude are important parameters that affect the feeding efficiency of the vibrating feeder. Generally speaking, increasing the vibration frequency can increase the material conveying speed, but too high a frequency may cause the material to jump too violently on the feeder, which is not conducive to the smooth conveying of the material; increasing the amplitude can increase the material conveying volume, but too large an amplitude will increase the wear and energy consumption of the equipment. Therefore, it is necessary to find the best combination of vibration frequency and amplitude through testing and debugging according to the characteristics of the material and the feeding requirements. For example, for materials with smaller particle size and better fluidity, the vibration frequency can be appropriately increased and the amplitude can be reduced; for materials with larger particle size and poorer fluidity, the amplitude needs to be appropriately increased and the vibration frequency needs to be reduced. ​

Inclination angle of the feeder: The inclination angle of the feeder also has a great influence on the conveying speed and conveying volume of the material. Within a certain range, increasing the inclination angle can speed up the material’s sliding speed and improve the feeding efficiency. However, if the inclination angle is too large, the material will slide down too fast, making it difficult to control the feeding amount. At the same time, it may also increase the impact of the material on the equipment and accelerate the wear of the equipment. Therefore, the inclination angle of the feeder should be reasonably adjusted according to the characteristics of the material and production requirements. Generally speaking, for materials with good fluidity, the inclination angle can be appropriately smaller; for materials with poor fluidity, the inclination angle can be appropriately larger, but usually it should not exceed 15°. ​

Material layer thickness: The accumulation thickness of the material on the feeder will also affect the feeding efficiency. If the material layer is too thick, it will increase the friction between the materials and reduce the material conveying speed; if the material layer is too thin, the conveying capacity of the feeder cannot be fully utilized. Therefore, according to the model of the feeder and the characteristics of the material, the discharge gate opening of the storage bin should be adjusted to control the accumulation thickness of the material on the feeder to keep it within a reasonable range.

三.Maintenance and care

1.Daily maintenance

Daily maintenance is an important measure to ensure the normal operation of the vibrating feeder and extend its service life. Before the equipment is operated every day, the appearance of the equipment should be inspected to check whether the parts are loose, deformed, worn, etc., and the loose bolts should be tightened in time, and the parts with severe wear should be replaced. At the same time, the lubrication system should be checked to ensure that the lubricating oil at each lubrication point is sufficient and the oil quality is good, and the lubricating oil should be added or replaced regularly.

During the operation of the equipment, pay attention to the temperature, vibration and sound of the equipment. If the equipment temperature is too high, the vibration is abnormal, or there is an abnormal sound, it should be stopped in time for inspection, find out the cause and deal with it. In addition, the material residue and dust on the feeder should be cleaned regularly to prevent the accumulation of materials and dust from entering the equipment and affecting the normal operation of the equipment.

2.Regular maintenance

In addition to daily maintenance, the vibrating feeder also needs to be maintained regularly. The period of regular maintenance can be determined according to the frequency of use of the equipment and the working environment. Generally, a comprehensive maintenance is carried out every period of time (such as one month or three months).

The content of regular maintenance includes inspection, cleaning, adjustment and replacement of various parts of the equipment. For example, check the bearing wear of the vibration motor and replace the worn bearings in time; clean the vibration springs, exciters and other parts of the equipment to remove oil and impurities; adjust the exciting force and installation angle of the vibration motor to ensure the good vibration performance of the equipment. At the same time, check the electrical system of the equipment to ensure that the electrical components are firmly connected and the insulation performance is good to prevent electrical failures. ​

3.Timely repair of faults ​

Despite good maintenance and care, the vibrating feeder may still have various faults during long-term operation. When the equipment fails, it should be repaired in time to avoid the expansion of the fault and affect production efficiency. The maintenance personnel should have professional technical knowledge and rich maintenance experience, be able to quickly and accurately determine the cause of the fault, and take effective maintenance measures. During the maintenance process, it is necessary to strictly follow the maintenance operation procedures to ensure the quality of the maintenance. For the replaced parts, it is necessary to select products with reliable quality and matching specifications and models to avoid the equipment from failing again due to parts quality problems. After the maintenance is completed, the equipment should be debugged and tested to ensure that the equipment is put into production after it resumes normal operation.

In summary, improving the production efficiency of the vibrating feeder requires multiple aspects and comprehensive and effective measures. Only by comprehensively optimizing each link can the performance advantages of the vibrating feeder be fully utilized and the production efficiency be improved.

The post How to improve the production efficiency of vibrating feeder? appeared first on JDminingseparation.

一.The equipment’s own performance factors

1.Crusher type

Different types of crushers are suitable for different crushing scenarios and materials, and their working principles and structural characteristics determine the difference in output. For example, jaw crusher mainly crushes materials through the mutual extrusion and bending of movable jaw and fixed jaw, which has the advantages of simple structure, reliable work and strong adaptability, and is commonly used in coarse crushing operation, but due to the limitation of its working mode, the output is relatively limited when dealing with a large amount of materials. The cone crusher adopts the principle of laminar crushing, squeezing materials through the movement of the rolling wall to the crushing wall, with large crushing ratio and high efficiency, especially suitable for medium and fine crushing of materials with high hardness, and the output performance is more outstanding in the case of large handling capacity and high requirements for product size. Impact crusher, on the other hand, makes use of the high-speed rotating impeller to throw out the materials and collide with the impact plate and other parts to crush them, which is suitable for the production of mechanism sand and the processing of brittle materials with medium hardness or below, and can achieve higher output under specific working conditions. Therefore, choosing the right type of crusher according to the material characteristics and production requirements is the basis for ensuring the output.

2.Equipment specifications and models

For the same type of crusher, there are significant differences in production capacity among different specifications and models. Generally speaking, the larger the specification of the crusher, the larger its crushing chamber volume, and the more material can be processed per unit time. For example, a large jaw crusher has a larger inlet size, which can handle larger lumps of material at one time, and is equipped with a more powerful motor, which can provide stronger crushing power and thus achieve a higher output.

3.Wear and tear of crushing parts

The crushing parts of the crusher, such as jaws, hammerheads, crushing walls, etc., will wear out in the long-term working process. When these parts wear to a certain extent, the shape and size of the crushing chamber will change, resulting in the change of the trajectory of the material in the crushing chamber, the crushing effect deteriorates and the output decreases. For example, when the jaw plate of the jaw crusher is worn out, its tooth shape will become blunt, and its ability of biting and crushing the material will be weakened, making it difficult for the material to be crushed effectively, and it needs to be crushed several times to reach the qualified size, thus reducing the output per unit of time. After the hammer head is worn, its striking force and crushing effect will also be greatly reduced, affecting the working efficiency of the crusher. Therefore, regular inspection and replacement of crushing parts with serious wear is an important measure to maintain stable output of the crusher.

二.The material characteristics of factors

1.Material hardness

Material hardness is one of the important factors affecting the output of the crusher. Materials with high hardness, such as granite, quartzite, etc., are difficult to crush and need to consume more energy in order to crush them into qualified size products. During the crushing process, the crusher needs to exert more pressure or impact force, resulting in increased workload of the equipment, lower crushing efficiency, and a corresponding reduction in output. In contrast, materials with lower hardness, such as limestone and gypsum, are relatively easy to crush, and the crusher is able to work with higher efficiency and higher output.

2.Material humidity

Material humidity has a significant impact on crusher output. When material humidity is high, the material tends to stick to the crushing components and conveying equipment, causing blockages and affecting the normal flow of material and the crushing process. For example, when dealing with wet clay, the clay will form mud clusters in the crushing chamber of the jaw crusher, blocking the inlet and outlet ports, resulting in the crusher not being able to work properly and a significant drop in output. In addition, materials with high humidity will be more difficult to crush during the crushing process due to the increased bonding between the particles, which further reduces the crushing efficiency. Generally speaking, the moisture content of materials should be controlled within a certain range to ensure the normal operation of the crusher and stable output.

3.Material size composition

The particle size composition of the material is directly related to the feeding situation and crushing process of the crusher. If the proportion of large materials in the feed is too high, the crusher needs to spend more time and energy to crush them, which will lead to lower efficiency and reduced output. On the contrary, if the feed size is more uniform and smaller, the crusher can carry out the crushing operation more smoothly and the output will be increased accordingly. In addition, the high content of fines in the material will also affect the output, because fines are easy to form a pile in the crushing chamber, hindering the flow of materials and reducing the crushing effect. Therefore, proper screening and pre-treatment of the material before feeding and controlling the particle size composition of the material are conducive to improving the output of the crusher.

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三.The operation and management factors

1.Feed uniformity

During the operation of the crusher, keeping the feed uniformity is the key to ensure stable output. If the feed is not uniform, sometimes more and sometimes less, it will lead to unstable crusher workload. When the feed is too much, the crusher may be overloaded, resulting in poor operation or even shutdown; when the feed is too little, the crusher can not give full play to its crushing capacity, and the output will be reduced. In addition, uneven feeding will also aggravate the wear and tear of crushing parts and shorten the service life of the equipment. Therefore, the use of suitable feeding equipment, such as vibrating feeder, belt conveyor, etc., and reasonable adjustment of the feeding speed, so that the material evenly and continuously into the crusher, can effectively improve the output.

2.Discharge size adjustment

Discharge size adjustment of the crusher directly affects the output. When the required discharge size is small, the crusher needs to crush the material more fully, the crushing process will be more complicated, the workload of the equipment increases, and the output decreases accordingly. On the contrary, an appropriate increase in discharge size can reduce the number of crushing, improve crushing efficiency and increase production. However, it should be noted that the adjustment of the discharge size should be carried out according to the actual production demand, and we can’t just pursue high output and neglect product quality. For example, in the production of construction sand, it is necessary to strictly control the discharge particle size to meet the requirements of building construction on sand grading and particle size.

3.Equipment maintenance and repair

Regular maintenance and repair of the crusher can ensure that the equipment is in good operating condition, so as to ensure stable production. Maintenance work includes checking the lubrication of the equipment, fastening parts, cleaning the crushing chamber and so on. Good lubrication can reduce the friction between the parts of the equipment, reduce the wear and tear, and improve the operating efficiency of the equipment; fasten the parts to prevent the equipment from loosening during operation, avoiding equipment failure and output decline due to the loosening of the parts; cleaning the crushing chamber can remove the residual material in time, preventing the accumulation of materials affecting the crushing effect. In addition, regular comprehensive inspection and maintenance of equipment, timely detection and resolution of potential problems is also an important measure to improve production and equipment life.

四.Environmental condition factors

1.Temperature of the working site

In a high temperature environment, the lubricant viscosity of the equipment will be reduced, and the lubrication effect will be poor, resulting in increased friction between the components, and the equipment is prone to overheating, which affects its normal operation and output. At the same time, high temperature will accelerate the aging and damage of equipment components. In the low temperature environment, the lubricant will thicken, poor fluidity, equipment start-up difficulties, operating resistance increases, will also have a negative impact on the yield. Therefore, in the extreme temperature environment, it is necessary to take corresponding measures, such as equipping the equipment with cooling devices or heating devices to ensure that the crusher works in the appropriate temperature range.

2.Dust content

High dust content in the working environment will have many adverse effects on the operation of the crusher. A large amount of dust will enter the lubrication system and transmission parts of the crusher, accelerating the wear and tear of the parts and reducing the reliability and service life of the equipment. At the same time, dust will also affect the electrical system of the equipment, leading to electrical failure. In addition, the accumulation of dust in the crushing chamber will also affect the crushing effect of materials and reduce the output. Therefore, it is important to equip the crusher workplace with effective dust removal equipment, such as bag duster, cyclone duster, etc., to reduce the dust content, which is an important condition to ensure the normal operation of the equipment and stable output.

3.Stable power supply

Stable power supply is the basis of normal operation of the crusher. If the power supply is unstable, voltage fluctuation, blackout, etc., it will seriously affect the output of the crusher. Low voltage will cause the crusher motor speed to drop, weakening the crushing capacity and reducing the output; frequent power outages will not only interrupt the production process, but also may cause damage to the equipment. Therefore, equipping the crusher with a stable power supply system, such as installing a voltage regulator and a backup generator, can effectively avoid the loss of production caused by power problems.

To sum up, the factors affecting the output of the crusher are manifold. In actual production, only by fully understanding these influencing factors and taking corresponding optimisation measures can we improve crusher efficiency and output, reduce production costs and create greater economic benefits for the enterprise.

The post What are the factors affecting crusher output? appeared first on JDminingseparation.

一.Technical Advantages of the TBS Interference Bed Sorter

1.Simple structure, easy maintenance

The overall structure of the teetered bed separator is relatively simple, mainly consisting of an inlet well, sorting drum, turbulent flow plate, density sensors, discharge valves and related piping components. Compared with some complex coarse coal slurry sorting equipment, it does not have too many moving parts and complex transmission devices. This makes the equipment in the operation process, the potential points of failure is greatly reduced. Routine maintenance mainly focuses on the cleaning of equipment surfaces, calibration of density sensors and checking of discharge valves, without the need for specialised and complex maintenance skills and a large amount of maintenance time.

2.High sorting accuracy

The teetered bed separator has excellent sorting accuracy, with an outstanding Ep value for possible deviations. Under ideal conditions, the Ep value of the TBS can be as low as 0.038, and is normally stable at around 0.08, with a guaranteed value of 0.12 being typical. This high accuracy enables the TBS to accurately separate impurities such as fine coal and gangue from the coarse coal slurry.

3.Large processing capacity

TBS interfering bed sorter has a strong sorting capacity per unit volume, usually, its sorting capacity per unit volume is about 3 times that of the traditional water classification equipment. Different models of TBS equipment processing capacity varies.

4.Sorting density can be controlled and adjusted

The TBS interfering bed sorter is equipped with an advanced density control system, which is capable of accurately regulating the sorting density. It has a wide range of effective sorting densities, which can be flexibly adjusted between 1.4-1.9g/cm³. In the actual production process, according to the change of coal quality and different requirements for product quality, the sorting density can be conveniently set and adjusted through the control system.

5.Low operating costs

On the one hand, the teetered bed separator does not require the addition of heavy media and chemicals during operation, and relies only on circulating water as the sorting medium. This greatly reduces the costs associated with media procurement, addition, recovery and media loss compared to equipment such as heavy-duty cyclones for coal slurry, which require the use of a large amount of micro-fine magnetite media.

二.Comparison between teetered bed separator and other coarse coal slurry sorting equipment

1.Comparison with coal slurry heavy-duty cyclone

Sorting accuracy: Coal slurry heavy-duty cyclone adopts small-diameter cyclone and sorts with higher feeding pressure and fine magnetite media. In the sorting process, the higher centrifugal coefficient makes the pulverised coal particles subjected to much larger force than that in the gravity field and the large-diameter heavy-duty cyclone, and the sorting accuracy is higher. However, TBS interfering bed sorter is not inferior in sorting accuracy, and its Ep value is similar or even lower than that of heavy media cyclone for coal slurry in some cases. For example, in some coal processing plants with very high requirements for coal quality, the teetered bed separator is able to achieve ash control of the coal product comparable to that of the slurry HRC, and in some cases, the Ep value of the teetered bed separator can be as low as 0.038, which is better than that of the common range of Ep values of the slurry HRC. Equipment Structure and Maintenance: The internal structure of the Coal Slurry Heavy Duty Cyclone is relatively complex and requires specialised media preparation, addition and recovery systems, as well as equipment to ensure the stability of the media suspension. This makes the maintenance of the equipment more difficult, requiring professional and technical personnel to operate and maintain, and maintenance costs are high. For example, coal slurry heavy media cyclone media recovery system, magnetite media purification, concentration and other links are prone to failure, once the failure occurs, the maintenance time is long and high cost. On the other hand, TBS interfering bed sorter has a simple structure, no complex media system, and the maintenance work mainly focuses on a few key components, so the maintenance difficulty and cost are significantly lower than that of the coal slurry heavy-medium cyclone. Running Costs: Due to the need to use a large number of fine magnetite media, the media procurement cost is high, and the media loss is large during the production process. At the same time, in order to ensure the recycling of the media and the sorting effect, the related equipment also has high energy consumption. In contrast, the TBS interfering bed sorter does not require heavy media, and only consumes a small amount of electricity to drive the rising water pump, so the operating cost is greatly reduced. According to statistics, the operating cost of the teetered bed separator is about 30%-40% lower than that of a heavy media cyclone for the same size of coarse coal slurry. Adaptability to changes in the feed material: The TBS is sensitive to changes in the nature of the feed material, such as particle size and density. When the coal slurry content, particle size composition or density distribution of the feed material changes, may lead to the stability of the media suspension is affected, which in turn affects the sorting effect, the need for frequent adjustment of equipment parameters. However, the teetered bed separator can adapt to changes in coal quality and maintain a relatively stable sorting effect by flexibly adjusting the speed and pressure of the rising water flow. For example, when the feed size range changes from 0.25-2mm to 0.15-3mm, the teetered bed separator only needs to adjust the upflow parameters appropriately to continue to ensure the quality and yield of the fine coal product, whereas the slurry heavy-duty cyclone may need to re-calibrate the entire media system.

2.Comparison with spiral sorter

Sorting precision: the sorting precision of spiral sorter is relatively low, its Ep value is generally around 0.2, which is significantly higher than that of TBS interference bed sorter. This makes it difficult for the spiral sorting machine to accurately separate the fine coal and gangue when separating the coarse coal slurry, resulting in the fine coal product may be mixed with more gangue and higher ash, which is unable to meet the market demand for fine coal with higher quality requirements. Sorting Density Control: The spiral sorter does not have a special density control system and cannot automatically control the sorting density accurately. Its sorting density range is relatively narrow, generally between 1.6-1.9g/cm³, which makes it incompetent in dealing with coal slurry that requires lower sorting density to obtain low-ash coal. The teetered bed separator is equipped with an advanced density control system, capable of accurately adjusting the sorting density within a wide range of 1.4-1.9g/cm³, to meet the sorting needs of different coal qualities and product quality requirements. Feeding requirements and product stability: the spiral sorter has high requirements for feeding, and needs a more uniform and stable feeding to ensure a better sorting effect. Once the feed fluctuations, product quality is easily affected, fluctuations. At the same time, the sorting tank of the spiral sorting machine is prone to wear and tear during long-term use, affecting the sorting performance and service life of the equipment. On the other hand, the teetered bed separator is more adaptable to the feed, does not need a complex feed distribution system, has a simple equipment structure, a low potential failure rate, and a relatively stable product quality. For example, during the production process of a coal preparation plant, when the feed fluctuates due to changes in raw coal mining conditions, the ash content and yield of the coal product of the spiral sorter will fluctuate greatly, while the teetered bed separator  is able to maintain relatively stable sorting indexes.

With its unique working principle, the teetered bed separator demonstrates a number of significant advantages, such as simple structure, high sorting accuracy, large processing capacity, controllable and adjustable sorting density, and low operating costs. In comparison with coal slurry heavy media cyclone, spiral separator and other traditional coarse coal slurry sorting equipment, teetered bed separator excels in all key performance indexes, and can better adapt to the complex and changing needs of coarse coal slurry sorting. In terms of sorting performance, the teetered bed separator has a wider range of effective sorting density and higher sorting accuracy. Some traditional classification equipment, such as certain types of shaking table, although in a specific size and density range has a certain effect, but in the treatment of coarse coal slurry such as particle size and density distribution of more complex materials, the sorting effect is far less than the teetered bed separator, the TBS can be more accurately realised coarse coal slurry according to the density of the sorting, to improve the yield and quality of fine coal. With the coal industry’s continuous pursuit of efficient and clean coal sorting technology, the teetered bed separator is expected to play a more important role in the future of coarse coal slurry sorting, and become one of the key equipment for the optimisation and upgrading of coal sorting process.

The post What are the advantages of teetered bed sorting machine and other coarse coal slurry sorting equipment? appeared first on JDminingseparation.

一.Factors affecting the sorting accuracy of the teetered bed separator

1.Equipment structure factors

Shape and size of the sorting tank: the shape and size of the sorting tank determines the distribution of the water flow and the movement of particles in the interference bed. Generally speaking, the proportion of the diameter and height of the sorting tank should be reasonable, if the diameter is too large, the rising speed of the water flow is difficult to be uniformly distributed, which will easily lead to turbulence in the sorting area, so that the particles can not be separated in accordance with the predetermined settlement law; if the height is too high, the particles in the bed of too long a time to stay, which will increase the opportunity for the mixing of fine particles and reduce the accuracy of the sorting. In addition, the irrational design of the bottom of the sorting tank may lead to local concentration or dispersion of water flow, destroying the stability of the interference bed. Water distribution device: water distribution device is a key component to ensure the uniform rise of water flow in the interference bed. If the opening rate and aperture distribution of the water distribution device are not uniform, it will make the water flow into the sorting tank when there is a difference in the flow rate, resulting in water flow turbulence in the bed. Overflow weir and bottom flow opening: the height and shape of the overflow weir affects the discharge of fine coal and the sorting effect. If the overflow weir is too high, the liquid level in the disturbing bed will rise, increasing the residence time of the particles in the bed, which may lead to fine particles being mixed into the fine coal; if the overflow weir is too low, the fine coal may be discharged too fast, and some particles that have not been sufficiently sorted will also be taken out, which will reduce the quality of the fine coal. Meanwhile, the size and adjustment of the bottom flow opening also affect the tailings discharge and bed stability.

2.Operating parameter factors

Rising water velocity: Rising water velocity is one of the core parameters affecting the sorting accuracy of the interfering bed sorting machine. Appropriate rising water velocity can make the particles in the bed form a stable state of interference settlement, to achieve accurate sorting by density. When the rising water velocity is too high, the particles will be carried upward by the water current, resulting in heavy particles can not be effectively settled, mixed into the light products; while the rising water velocity is too low, the light particles can not be adequately suspended, and will be settled into the tailings with the heavy particles, which reduces the yield of refined coal and sorting accuracy. Feeding flow rate: the size of the feeding flow rate directly affects the concentration and movement state of the particles in the interference bed. Feeding flow is too large, it will make the concentration of particles in the bed too high, and the mutual interference between particles will be intensified, which will affect the settling speed of particles and sorting effect; Feeding flow is too small, it will make the bed unstable, and the particles can not be fully dispersed in the bed, and it will also reduce the sorting precision.

3.Characteristic factors of the feed

Particle size composition: the particle size composition of the feed has a significant impact on the sorting accuracy of the interfering bed sorting machine. Generally speaking, the interfering bed sorting machine is suitable for sorting materials with a certain range of particle size. When the content of fine particles in the feed is too high, the fine particles will form colloidal substances in the bed, increase the viscosity of water, impede the settlement of coarse particles, resulting in poor sorting effect between coarse particles and fine particles; at the same time, the fine particles are easy to be adsorbed on the surface of the coarse particles, so that the apparent density of coarse particles changes, affecting the accuracy of sorting by density. When the content of coarse particles in the feed is too high, the coarse particles will settle quickly, destroying the stability of the bed and also reducing the sorting accuracy. Density composition: the density composition of the feed directly determines the difficulty of sorting. If the density difference between light and heavy particles in the feed is large, the sorting is relatively easy, and the sorting accuracy is also high; but when there are a large number of intermediate density particles in the feed, these particles in the disturbed bed of the settlement behaviour is complex, and it is easy to mis-select them, resulting in a decline in the sorting accuracy. In addition, the fluctuation of density composition in the feed will also bring difficulties to sorting, and it is necessary to adjust the operating parameters in time to ensure the sorting precision.

二.Methods to enhance the sorting accuracy of the interference1. Bed sorter

1.Optimise the equipment structure

Reasonable design of the sorting tank: according to the nature of the material to be processed and the processing capacity, the ratio of the diameter and height of the sorting tank can be reasonably determined. Generally speaking, for the common teetered bed separator, the ratio of diameter and height can be controlled within a certain range to ensure the uniform distribution of water flow in the bed and the effective sorting of particles. At the same time, the shape of the bottom of the sorting tank is optimised, and a reasonable inflow structure is adopted so that the water flow can rise uniformly and reduce the generation of turbulence. In addition, set appropriate anti-stick and wear-resistant materials on the inner wall of the sorting tank to prevent material adhesion and abrasion and ensure the normal operation and sorting effect of the sorting tank. Improvement of water distribution device: choose suitable water distribution device to ensure uniform distribution of the opening rate and hole diameter of the water distribution holes, and improve the uniformity of the water flow. New water distribution technology can be used, such as porous plate water distribution, ring water distribution, etc., so that the water flow can be evenly dispersed when entering the sorting tank. Regularly check and clean the water distribution device to prevent the water distribution holes from being blocked and worn out to ensure the effect of water distribution. At the same time, improve the installation precision of the water distribution device to ensure that its level meets the requirements and avoid water flow offset. Optimise the overflow weir and underflow opening: reasonably adjust the height and shape of the overflow weir according to the requirements of the sorting process. Through test and practice, determine the best overflow weir height to ensure the quality and yield of fine coal. For the underflow opening, an adjustable structure is adopted, and the size of the underflow opening is adjusted in time according to the nature of the incoming material and the operation situation, so as to ensure the smooth discharge of the tailings and the stability of the bed. At the same time, the maintenance of overflow weir and underflow opening is strengthened to prevent wear and clogging and ensure their normal operation.

2.Optimise the operating parameters

Precise control of the rising water flow rate: a high-precision water flow rate monitoring device is installed to monitor the rising water flow rate in real time. According to the nature of the feed material and sorting requirements, adjust the flow rate or pressure of the water pump to precisely control the rising water velocity within a suitable range. Establish the mathematical model of rising water velocity and sorting effect, use advanced control algorithms to achieve automatic adjustment of rising water velocity to adapt to changes in the nature of the feed to ensure the stability of sorting accuracy. Stabilise the feeding flow: adopt constant flow feeding equipment, such as quantitative pumps, variable frequency speed feeders, etc., to ensure the stability of the feeding flow. Set the monitoring and feedback system of feeding flow, when the feeding flow fluctuates, adjust the operating parameters of the feeding equipment in time, so that the feeding flow is restored to the set value. At the same time, reasonably arrange the production process to avoid the fluctuation of feed flow caused by the fluctuation of other links, to ensure the stable operation of the interfering bed sorting machine.

3. Improve the characteristics of the incoming material

Pre-grading treatment: Before the incoming material enters the disturbed bed sorting machine, adopt suitable grading equipment, such as vibrating screen, hydrocyclone, etc., to pre-grade the incoming material. Separate the materials with large differences in particle size, so that the composition of the particle size of the materials entering the interfering bed sorting machine is more uniform, and reduce the influence of fine particles and coarse particles on the sorting effect. For materials with too high content of fine particles, some of the fine particles can be pre-separated through classification, and other suitable sorting methods can be used to improve the overall sorting accuracy. Desliming treatment: for the feed material with high coal sludge content, desliming treatment is carried out. Desliming screen, arc screen and other equipment can be used to separate the coal sludge from the feed. The desliming treatment can reduce the water flow resistance in the disturbed bed, improve the settling characteristics of the particles, and reduce the influence of coal sludge on the sorting effect. In addition, methods such as adding flocculants can be used to promote the agglomeration and settlement of coal sludge and improve the desliming effect. Uniform nature of the feed material: strengthen the management and deployment of the feed material, try to ensure that the density composition and particle size composition of the feed material is relatively uniform. Establish raw material storage and blending system, make reasonable matching and mixing for different sources and different nature of raw materials to reduce the fluctuation of the nature of the feed material. At the same time, strengthen the real-time monitoring of the nature of the feed material, when the nature of the feed material is found to have large changes, timely adjustment of the operating parameters of the sorting equipment to ensure that the sorting accuracy is not affected.

In summary, the sorting accuracy of the teetered bed separator is affected by a variety of factors such as equipment structure, operating parameters and feeding characteristics. In the actual production process, according to the specific circumstances, we need to comprehensively use various methods to effectively improve the sorting accuracy of the teetered bed separator.

The post What factors affect the sorting accuracy of the teetered bed separator? appeared first on JDminingseparation.

一.Working Principle

Feed and water flow to form a disturbance layer: slurry tangentially fed into the feed well of the equipment, according to the predetermined pressure and flow rate by the pump will be pumped into the distributor at the bottom of the separator, through the turbulent plate evenly distributed to the bottom of the disturbance bed separator, forming upward disturbing water flow. The falling material meets with the rising water flow and forms the disturbance layer or called boiling bed layer.

Particles according to the density difference settlement: the particles in the feed in the sorting machine for the interference settlement movement, due to the different density between the particles, so that the interference settlement speed difference. When it reaches a stable state, the particles in the feed whose density is higher than the average density of the disturbed bed will pass through the bed to enter the sedimentation stream and be discharged through the discharge port at the bottom; while the particles whose density is lower than the average density of the disturbed bed will float upward with the rising water flow and enter the overflow product as the refined coal.

Density sensor control discharge: the discharge valve is controlled by the signal from the density sensor in the disturbed bed. The density sensor monitors the bed density in real time and feeds the signal back to the control system, which controls the degree of opening and closing of the discharge valve according to the result of comparing the actual density with the set density value, thus regulating the discharge of materials in the bed and keeping the bed density within the predetermined range. For example, if the actual density is too high, then increase the opening degree of the discharge gate to exclude the high-density materials in the bed; on the contrary, reduce the discharge of materials in the bed.

二.Uses

1.Coal washing field

Coarse coal slurry sorting: TBS is mainly used for coarse coal slurry sorting in coal washing plant. In actual production, a certain amount of coarse coal slurry will be generated from the raw coal after crushing, screening and other pre-processing. If these coarse sludges are not sorted efficiently and enter the subsequent process directly, the quality and yield of fine coal will be affected. By sorting the coarse slurry through TBS, the fine coal and impurities such as gangue can be effectively separated. Optimisation of washing process: The application of TBS helps to optimise the whole coal washing process. In the traditional coal washing process, a large amount of coal slurry will enter the heavy media system, TBS can pre-sort the coarse coal slurry before the heavy media system, which greatly reduces the amount of coal slurry entering the subsequent heavy media system, and generally improves the handling capacity of the heavy media system by 20% and reduces the media consumption by 40%. At the same time, the sorting effect of TBS can also reduce the flotation throughput, because after TBS sorting, the nature of the materials entering the flotation process is more single, which is conducive to the stability of the flotation process and improve the efficiency of flotation. (ii)

2.Mineral Processing

Mineral Sand Processing: In typical mineral sand applications, TBS is often used in conjunction with a spiral separator. In some beach sand processing, TBS can be used at the front end of the plant for desliming and removing light and heavy vein minerals. As beach sand ores often contain large amounts of muddy impurities and pulsed minerals that can interfere with the subsequent extraction of useful minerals, the TBS, through its unique sorting action, is able to remove the mud and some of the pulsed minerals, reducing the processing pressure on the subsequent plant, and helping to smooth out fluctuations in the flow of material into the plant to ensure stability of the production process. Other Minerals Sorting: TBS can also play an important role in the processing of other minerals. In the beneficiation of some non-ferrous ores, such as lead and zinc ores, the TBS can sort the milled product to separate lead and zinc minerals with different densities from the vein minerals and increase the enrichment of useful minerals. In the beneficiation of iron ore, TBS can sort the fine-grained iron ore, remove the vein impurities, improve the grade of iron ore concentrate, and provide better raw materials for the subsequent smelting process.

三.Advantageous features

1.Simple structure

The overall structure of TBS is relatively simple, mainly composed of several key components mentioned above, without complex mechanical transmission devices and excessive wearing parts. Compared with some traditional sorting equipment, such as complex re-election shaking table, TBS reduces a large number of mechanical parts, which makes the manufacturing and installation process of the equipment easier and reduces the initial investment cost of the equipment. At the same time, the simple structure also means that the failure rate of the equipment in the operation process is low, reducing the workload and cost of equipment repair and maintenance, improving the reliability and stability of the equipment, providing a strong guarantee for the continuous production of enterprises.

2.Precise control

TBS is equipped with advanced density detection device and automatic control system. The density sensor in the interference bed can monitor the density change of materials in the bed in real time and accurately. Once the density fluctuates, the control system will immediately adjust the opening of the discharge valve and key operating parameters such as the flow rate and pressure of the rising water stream according to the preset parameters. For example, when the density of the bed rises due to a sudden increase in the content of high-density material in the feed, the control system will quickly increase the opening of the discharge valve to increase the amount of material discharged, and at the same time, adjust the speed of the rising water flow appropriately, so as to bring the density of the bed back to the normal set value. This precise control ability can ensure that TBS always maintains efficient and stable sorting effect under different feeding conditions, and improve the consistency and stability of product quality.

3.Excellent sorting effect

Accurate sorting based on density: TBS is based on the principle of particle density difference for sorting, which enables it to accurately separate particles of different densities in complex material systems. In the process of coal washing and mineral processing, it can effectively separate the concentrate and impurities, and improve the purity and quality of the products. Wide range of processing size: TBS has a wide range of sorting size, generally 0 – 5.0mm, the best sorting size is 2.0mm – 0.25mm, which makes it able to adapt to a variety of different particle size composition of the material sorting needs. In some coal washing plants, the coarse coal slurry produced after crushing has a wide range of particle size, TBS can effectively sort the coarse coal slurry within this range, without the need to classify the material too finely, which simplifies the process and improves the production efficiency. High processing capacity and low fine coal ash content: TBS has high processing capacity per unit area, which can meet the demand of large-scale production. At the same time, the ash content of the refined coal product obtained by its sorting is low, for example, in coal washing application, the ash content of the refined coal can be reduced by less than 10% through TBS sorting, which greatly improves the market competitiveness of the product and creates higher economic benefits for the enterprise.

4.Green and environmental protection

One of the biggest characteristics of TBS is that it does not use any medium and chemicals, and only uses circulating water to sort materials effectively. Compared with some sorting equipment that requires the use of a large number of chemicals or heavy media, TBS avoids the environmental pollution caused by the use of these media and agents. The circulating water used in TBS can be reused after simple treatment, which greatly reduces the waste of water resources and the negative impact on the environment, and meets the requirements of environmentally friendly production.

四.Application fields

1.Coal industry

In modern large-scale coal washing plant, TBS has become one of the key equipments. TBS’s high efficiency sorting capacity, large processing capacity and optimisation of the washing process can quickly and accurately sort large quantities of coarse coal slurry, improve the yield and quality of fine coal, and reduce the production cost, bringing significant economic benefits to the enterprise. It can quickly and accurately sort a large amount of coarse coal slurry, improve the yield and quality of fine coal, reduce the production cost, and bring significant economic benefits for the enterprise.

2.Mining industry

In the beneficiation process of copper, lead, zinc, tin and other non-ferrous metal ores, TBS can be used to sort the products after grinding. As non-ferrous minerals are usually closely co-occurring with chalcopyrite minerals, after grinding, the density difference of different mineral particles becomes an important basis for sorting, TBS can effectively separate non-ferrous minerals from chalcopyrite minerals according to this density difference, improve the enrichment of non-ferrous minerals, and provide high-quality concentrates for subsequent smelting process. In some large-scale copper ore processing plants, TBS is used in conjunction with other processing equipment, greatly improving the grade and recovery of copper concentrate.

3.Other areas

Construction materials industry: In the construction materials industry, such as the production of sand and gravel, TBS can be used to remove mud and other impurities from sand and gravel and improve the quality of sand and gravel. Sand and gravel for construction have higher requirements on purity and particle grade, through the sorting effect of TBS, it can effectively remove mud, mica and other low-density impurities in sand and gravel, make sand and gravel particles more uniform and pure, meet the demand for high-quality sand and gravel in construction projects, and improve the performance and quality of construction materials. Environmental protection field: TBS can also play a role in some environmental protection projects. In the sludge treatment process of municipal sewage treatment plants, TBS can be used to separate different components in the sludge. Sludge contains a variety of organic substances, heavy metals and gravel and other particles, TBS through the density difference can be separated from the gravel and other heavy particles, to facilitate the subsequent further treatment and disposal of sludge, reduce the difficulty and cost of sludge treatment, but also help to achieve the recycling of resources.

As an advanced gravity separation equipment, Teetered Bed Separator (TBS), with its unique working principle, wide range of applications, significant advantages and features, and successful applications in many fields, provides powerful technical support for the development of mineral processing, coal washing and other industries. With the continuous progress of science and technology and the increasing requirements for the efficient use of resources and environmental protection, TBS is expected to be further optimised and innovated on the basis of the existing ones, expanding its application scope, improving the sorting efficiency and precision, and making greater contributions to the sustainable development of the related industries.

The post What is Teetered Bed Separator (TBS)? appeared first on JDminingseparation.

一.The linear vibrating screen sieve is not clean common cause analysis

1.The equipment’s own factors

sieve problem

The size of the aperture of the screen mesh is a key factor in whether the size of the material to be screened is matched with the particle size. If the screen mesh aperture is too large, the materials smaller than the set particle size may be mixed into the screen, resulting in low purity of the screened material; on the contrary, if the aperture is too small, it will make it difficult for the materials that meet the requirements of the particle size to pass through the screen mesh, resulting in insufficient output of the screened material, which is also prone to lead to screen clogging. In addition, the material and weaving of the screen will also affect the screening effect. For example, the metal screen mesh high strength, but poor flexibility, easy to wear due to the impact of the material and friction; plastic screen mesh flexibility is good, but the strength is relatively low, suitable for screening more corrosive or smaller size of the material. Insufficient tension of the screen is also a common problem, the tension is not enough will lead to the screen in the vibration process to produce relaxation and deformation, affecting the trajectory of the material, thus reducing the screening efficiency. The parameters of the vibration motor are set unreasonably

The vibration motor is the power source of the linear vibrating screen, and its parameter settings directly determine the vibration intensity and frequency of the screen surface. The rotational speed of the vibration motor and the angle of the eccentric block are two key parameters. Too high rotational speed will make the screen surface vibration frequency is too high, the material in the screen surface jump height is too large, the residence time is too short, resulting in fine-grained materials can not pass through the screen mesh in time; rotational speed is too low will make the vibration intensity is not enough, the material can not be sufficiently loose and stratification, affecting the screening effect. The size of the eccentric block angle determines the size of the vibration direction angle, when the angle is too large, the material on the screen surface forward speed is too fast, shortening the screening time; angle is too small, the material moves forward slowly, may be piled up on the screen surface, also affecting the screening efficiency. Inappropriate screen inclination

The inclination angle of the screen is the angle between the screen surface and the horizontal plane, which has an important influence on the movement speed and residence time of the material on the screen surface. Inclination angle is too large, the material in the sieve surface decline speed, stay time shortened, fine-grained materials can not be screened in time to be discharged from the sieve body; inclination angle is too small will make the material in the sieve surface moving slowly, or even stagnation phenomenon, resulting in a reduction in the utilisation rate of the screen surface, the decline in screening efficiency. In addition, the angle of inclination of the screen surface will also affect the processing capacity of the vibrating screen, which needs to be reasonably adjusted according to the characteristics of the material and screening requirements. Amplitude and frequency mismatch

Amplitude and frequency are two important indicators to measure the vibration strength of linear vibrating screen. Amplitude is too large, the material on the screen surface is thrown up too high, easy to cause material splash and loss, but also increase the wear and tear of equipment and energy consumption; amplitude is too small can not make the material fully loose and stratification, affecting the screening effect. Too high a frequency will make the vibration of the material on the screen surface is too violent, resulting in fatigue damage to the screen mesh; too low a frequency can not provide enough vibration energy, so that the material is difficult to pass through the screen mesh. Therefore, the amplitude and frequency need to be based on the nature of the material, particle size distribution and screening requirements for a reasonable match.

2.Operation and Maintenance Factors

Uneven feeding

In the working process of linear vibrating screen, uneven feeding is one of the common reasons that lead to the screen not being clean. If the feeding volume is large or small, or the material is unevenly distributed on the screen surface, it will make the screen surface locally overloaded, while other areas are underloaded, thus affecting the overall screening effect. For example, when the feeding material is concentrated on one side of the screen surface, it will cause the material on that side to pile up too thick, and the screening is not sufficient, while the screen surface on the other side is not fully utilised. Excessive feed rate

Excessive feed rate can cause the screen surface to be instantly overloaded with material beyond its capacity. The material on the screen surface can not be fully screened before being discharged, resulting in a large number of unscreened fines in the screened material, and the purity of the screened material will also be affected. In addition, the feed rate is too fast may also lead to the formation of material on the screen surface clogging, further reducing the screening efficiency. Screen clogging and breakage

Screen clogging is a problem often encountered by linear vibrating screen in the screening process, especially when screening materials that are wet, sticky or contain more fine powder. The fine powder and impurities in the material will be adhered to the mesh of the screen mesh, gradually forming a blockage, so that the effective screening area of the screen mesh is reduced, and the screening efficiency is reduced. Sieve mesh damage will lead to larger particle size materials mixed into the sieve, affecting product quality. Screen clogging and damage if not found and dealt with in a timely manner, will further aggravate the deterioration of the screening effect.

3.Material characteristic factors

Material humidity

The humidity of the material is one of the important factors affecting the screening effect of linear vibrating screen. When the humidity of the material is large, the moisture in the material will make the fine-grained material bonded to each other, forming clumps, and it is difficult to pass through the screen. At the same time, the wet material is easy to adhere to the screen, blocking the screen holes and reducing the effective screening area of the screen. For materials with high water content, ordinary linear vibrating screen is often difficult to achieve the ideal screening effect, and need to take special processing measures. Material particle size distribution

The particle size distribution of the material has a significant impact on the screening effect. If the material particle size close to the screen hole size of the particle content is high, that is, the so-called ‘critical particles’ more, these particles in the screen surface is prone to ‘jamming’ phenomenon, resulting in a decline in screening efficiency. In addition, the ratio of coarse and fine particles in the material will also affect the screening effect. When the content of coarse-grained materials is high, fine-grained materials are easy to pass through the screen in the gap between the coarse-grained materials, and the screening efficiency is higher; on the contrary, when the content of fine-grained materials is high, it is easy to form a pile up on the sieve surface, which affects the coarse-grained materials screening. Material Viscosity

Materials with high viscosity are easy to adhere to the sieve mesh, forming a layer of sticky film, which prevents the material from passing through. At the same time, the viscosity of the material on the screen surface fluidity is poor, it is difficult to fully loose and stratification, resulting in poor screening results. For example, when screening materials containing more viscous impurities, it is necessary to increase the vibration intensity or take other auxiliary measures to improve the screening effect. Shape of material particles

The shape of material particles also has a certain influence on the screening effect. Generally speaking, spherical or nearly spherical particles are easier to pass through the screen, while flakes, needles or irregularly shaped particles are prone to clogging at the screen holes. For example, when screening flaky materials, due to its special geometric shape, it is often necessary to use larger screen holes or special screen structure to achieve a better screening effect.

二.The method of improving the screening effect of linear vibrating screen

1.Equipment adjustment and optimisation

Reasonable selection and replacement of screen mesh

According to the characteristics of the material and screening requirements, select the appropriate screen mesh aperture, material and weaving method. In selecting the screen aperture, the required screening material size and screening efficiency should be considered, generally speaking, the screen aperture should be slightly larger than the upper limit of the required screening material size. For occasions with high screening precision requirements, you can choose multi-layer screen, through the combination of different aperture screen, to achieve more accurate grading. Regularly check the wear and tear of the screen mesh, timely replacement of broken or clogged screen mesh, to ensure the effective screening area of the screen mesh. At the same time, pay attention to the tension of the screen mesh, the installation of the screen mesh should use a special tensioning device to ensure that the screen mesh in the vibration process to maintain a taut state. Optimise the parameters of the vibrating motor

According to the nature of the material and screening requirements, reasonably adjust the rotational speed of the vibrating motor and the angle of the eccentric block. Generally speaking, for the larger particle size, specific gravity of the material, should choose a higher rotational speed and larger eccentric block angle, in order to increase the vibration intensity and the forward propulsion speed of the material; for the smaller particle size, lighter specific gravity of the material, should choose a lower rotational speed and smaller eccentric block angle, in order to extend the residence time of the material in the sieve surface, to improve the screening efficiency. When adjusting the parameters of the vibration motor, it should be noted that the parameters of the two vibration motors should be set consistently to ensure the symmetry and stability of the screen vibration. Adjust the screen surface inclination angle

According to the characteristics of the material and screening requirements, adjust the screen surface inclination angle appropriately. Usually, the adjustment range of screen surface angle is between 0°-15°. For the liquidity of the material, you can appropriately increase the sieve surface angle to improve the processing capacity of the material; for the liquidity of the material, you should reduce the sieve surface angle, in order to prolong the residence time of the material in the sieve surface, to improve the screening effect. When adjusting the screen surface angle, attention should be paid to the overall stability of the equipment to avoid tilting the equipment or material splashing due to the large angle. Matching Amplitude and Frequency

Determine a suitable combination of amplitude and frequency through testing and debugging. Generally speaking, there is a certain matching relationship between amplitude and frequency, and for different materials and screening requirements, it is necessary to find an optimal balance. In practice, you can first fix the amplitude, adjust the frequency, observe the screening effect; then fix the frequency, adjust the amplitude, make a comparative analysis, and finally determine the best amplitude and frequency parameters.

2.Operation and maintenance optimisation

Ensure uniform and stable feeding

Install suitable feeding equipment at the feeding end of the linear vibrating screen, such as vibrating feeder, belt conveyor, etc., to ensure that the material enters the screen body uniformly and stably. The feeding speed of the feeding equipment should be matched with the processing capacity of the linear vibrating screen, to avoid the feeding volume being suddenly large or small or concentrated in a certain area of the screen surface. At the same time, pay attention to the direction of feeding, the material should be uniformly distributed along the width direction of the screen surface, in order to make full use of the effective area of the screen surface. Control feeding speed

According to the model, specification and material characteristics of the linear vibrating screen, it is reasonable to control the feeding speed. The feeding speed can be achieved by adjusting the rotational speed of the feeding equipment or the gate opening. In the production process, it should pay close attention to the material accumulation on the screen surface, and when it is found that the material accumulation on the screen surface is too thick, the feeding speed should be reduced in time; when the material on the screen surface is less, the feeding speed can be increased appropriately to give full play to the processing capacity of the equipment.

3.Material pre-treatment

Reduce the humidity of the material

For materials with large humidity, pre-treatment measures such as drying, airing, etc. can be taken to reduce the moisture content of the material and improve the fluidity and screening performance of the material. Adjust the particle size distribution of the material

If the critical particle content in the material is high, the critical particles can be separated in advance by pre-screening methods to reduce their impact on the screening process. Improve material viscosity

For materials with high viscosity, appropriate amount of dispersant or lubricant can be added to reduce the viscosity of the material and improve the fluidity of the material.

The reasons why the linear vibrating screen is not clean are manifold, involving the equipment itself, operation and maintenance factors and material characteristics. To improve the screening effect of linear vibrating screen, it is necessary to start from the adjustment and optimisation of equipment, operation and maintenance optimisation, material pretreatment, and the use of new technology and equipment, etc., and comprehensively consider the impact of various factors to develop a reasonable solution.

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