A new type of coarse particle flotation machine for rough grinding and flotation in mines

 Coarse ore flotation has always been one of the key technologies for mine coarse grinding and flotation to reduce energy consumption. An iron ore plant in Anhui Province has a very small content of mica in the iron ore of the first grinding product. Recovery value. However, there are generally two ways to recover mica at present: one is coarse-grained regrind and reselection; the other is to choose equipment suitable for coarse-grained mineral flotation. However, during the inspection of the production site, it was found that many of the mica minerals in the second-stage grinding products in this iron ore did not meet the particle size requirements of flotation, and the density of mica was small, and most of them showed flaky structure. The overflow of the cyclone ran out, causing the inspection and screening operation to be blocked first, so regrinding is not suitable for the recovery of coarse mica.

    The design principle of coarse-grained flotation machine is that coarse-grained minerals are prone to sinking grooves and poor selection indicators during the flotation process. On the basis of conventional flotation machines, the following principles will be followed for design (1 ) U-shaped groove bottom is used to reduce dead angles and avoid mineral sinks; (2) Large impellers and low speed drive are used to reduce the turbulence intensity of the slurry, which is conducive to the floating of coarse particles; (3) Equipped with larger At best, relatively many bubbles are formed, which can help attach and carry large particles to float; (4) Reduce the overflow strength of the bottom of the tank, shorten the rising distance of mineralized bubbles, reduce the interference of external forces and the roughness of the bubbles (5) Stabilize the separation zone and the surface of the slurry to ensure that the foam adsorbing minerals flows smoothly into the foam tank.

The structure design of the coarse particle flotation machine:

(1) Impeller and stator.

According to the fluid dynamics design theory, the impeller design of the flotation machine adopts a shape that is relatively similar to the impeller of a high specific speed pump. The tangentially rotating ore flow it produces is conducive to the suspension of minerals, the dispersion of air, and the selection index. improve. The stator must be able to convert the tangentially rotating slurry flow generated by the impeller into a radial slurry flow, and lift the coarse materials and dense minerals to the upper part of the tank, so that the mineral particles can be effectively suspended in the flotation tank. The contact probability of large mineral particles with bubbles increases the possibility of separation of coarse minerals and heavy particles.

(2) Impeller height

The height of the impeller from the bottom of the tank is related to the structural parameters of the flotation machine, the concentration of the slurry, and the composition of the particles. The greater the height, the easier it is to start the flotation machine, but it is easy to cause the sinking tank of the ore particles in the tank and the fluctuation of the slurry surface. Lower the height, the mineral particles are not easy to sink, but the suspended state is easily destroyed, the phenomenon of stratification occurs, and the flotation conditions are deteriorated. The appropriate height of the impeller from the bottom of the groove can be determined through experiments.

(3) Regulating device at best

The aeration volume of the flotation machine varies with the different minerals, and the selection index of some minerals is very sensitive at best. Therefore, we have designed a stepless speed regulation device at best to realize the fine adjustment of the aeration volume, so that the right amount of low-pressure air is evenly dispersed in the entire flotation tank to ensure that the non-floating mineral particles and mineralized bubbles in the upper separation zone of the tank body Separate.

According to the hydrogeological conditions of the wellbore project, the freezing method can be adopted for construction, short-section digging and building, rolling shift operation system, implementation of mechanized comprehensive supporting operation lines, multi-process parallel and intersecting operations, reducing auxiliary operation time, improving work efficiency, and fully Mobilizing the enthusiasm of employees has enabled the wellbore to break through the 100-meter mark for several consecutive months, achieving the goal of high-quality and efficient work.

How to perform high-intensity work on filter thickener

 The process adopted by the coal industry in my country is mainly based on wet coal preparation, and a large amount of slime water will be produced in the process of coal processing. Therefore, the treatment of slime water is a key link in the production of a coal preparation plant. The operation of the slime water system is related to whether the coal preparation plant can be normally produced. At the same time, it also involves the water of the coal preparation plant and the recovery of coal resources. Protect many aspects of the ecological environment. The thickening and clarification of slime water is an important link in the treatment of slime water. Under the current situation, we can use the rake thickener based on the principle of gravity sedimentation as the main equipment to apply, and then use the principle of gravity sedimentation to concentrate the slime water The equipment efficiency drops greatly, which will cause the overflow water concentration to exceed the standard, which will have a serious impact on the washing equipment. Therefore, further development of the new type of concentration equipment is very necessary.

The filter thickener is a new type of thickening equipment. Its working principle is different from the current thickening equipment in coal preparation plants. When the equipment is running, the filter slurry will be continuously pumped through the feed pipe by the internal filter and The filter room enclosed by an external static body. And to maintain a full state, use the pressure difference between both sides of the rotor to achieve filtration and concentration. The flow state of the slurry in the filter chamber is related to the speed of the rotor. When the speed of the rotor reaches a certain limit value, A kind of annular vortex called Taylor vortex will be generated. Adjacent Taylor vortices will be connected at a certain axial flow rate to prevent the axial reverse flow or short circuit of the liquid flow. Therefore, the liquid flow between the outer cylinders It is an ideal columnar flow. The slurry in the filter chamber undergoes a top-down rotational movement under the combined action of the resistance of the outer wall, gravity and centrifugal force. When flowing through the area, the pressure difference between the two sides of the filter medium will be used for the outer wall of the rotor. A filter cake is formed. When the filter rotor rotates, the filter cake on the medium will be subjected to the action of shearing and sweeping, thereby achieving filtration and concentration under the thin cake layer. Finally, the filtrate will pass through the filter medium and be discharged from the discharge port inside the drum to complete the filtering and concentration effect.

However, through the simulation of the filter thickener, it is found that the change of the internal flow field is related to the concentration of the feed, the speed of the drum, the pressure of the feed, and the opening of the concentrate outlet valve. Therefore, according to the simulation results, It is used to analyze the influence of the four factors of the concentration of the feed, the rotating speed of the drum, the pressure of the feed, and the opening of the concentration outlet valve on the concentration effect. The range analysis of the experimental results shows that: (1) The higher the feed pressure, the lower the concentration of the concentrate. This is because as the feed pressure increases, the driving force of the filtration process increases, and Wyeth is many small The particles penetrate the essence into the clarified liquid; (2) The smaller the opening of the concentrated liquid outlet valve, the greater the concentration of the concentrate. This is because the reduction of the valve opening makes the filtration time longer and the filtration pressure increases. Increase the filtration capacity of the clean water; (3) The feed concentration increases, and the concentrate concentration increases. This is because the thickness of the filter cake and the filtration resistance increase with the increase in the feed concentration, so that the ability to trap fine particles changes Strong; (4) If the rotating drum speed is too fast, the concentration of the clarified liquid will increase. This is because the rotating drum speed is too fast and the centrifugal force field will increase the filtration resistance.

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A new technology of high-efficiency concentration of ore slurry--filter thickener

 Most of the current thickening equipment is based on rake thickeners. The rake thickeners use the principle of gravity sedimentation to achieve concentration and clarification. This can be widely used in washing water clarification and other links, but with mechanization Continuous popularity and progress. The concentration efficiency of equipment using the sedimentation principle will be greatly reduced, which will cause the overflow concentration to exceed the standard and affect normal production. Therefore, in this case, we have to further carry out a necessary study on the principle of suspension and sedimentation and the enrichment equipment.

Under such circumstances, a new type of filter thickener that uses the principle of pressure filtration to achieve the old high-efficiency slurry thickener is proposed. Compared with the gravity sedimentation thickener, the filter thickener has the advantages of fast concentration speed, high concentration efficiency, quick concentration adjustment, and small volume. The structure of the filter thickener is mainly composed of two parts: an external static body and an internal filter rotor component. The external static body is composed of a central cylindrical section and two upper and lower conical sections. The cylindrical section is the main area for concentration operations. ; The filter rotor component is composed of a filter drum in the middle and two upper and lower rotating shafts. The lower rotating shaft is a hollow shaft, which is used to discharge the clarified liquid.

The filter thickener is a new type of technology that can use the principle of pressure filtration to achieve high-efficiency thickening of the slurry. Its working principle is: the slurry is fed into the filter thickener along the tangential direction through the feed pipe at a certain pressure. , Under the combined action of gravity, the top-down rotating movement is carried out; when the slurry flows through the filter area, the pressure of the slurry is used to form a filter cake on the outer wall of the filter rotor, and the permeable liquid will be collected through the filter medium To the inside of the filter rotor, the material is discharged from the outlet; the sediment on the filter medium is washed by centrifugal force and liquid flow. Under the action of disturbance, the slurry is mixed into the slurry to form a concentrate and discharged from the discharge port, thereby completing the filtration and concentration process of the slurry.

In addition, research shows that the pressure field distribution law of the filter thickener is more consistent with the theoretical expected results, so the research results are credible; the drum speed has a direct impact on the pressure of the flow field, so in the actual application process It is possible to use the adjustment effect of the rotating drum speed on the smooth pressure to change the concentration effect of the thickener, and realize more rapid adjustment; there is a certain pressure drop on both sides of the drum wall, and the outer pressure value is greater than the inner pressure value. The guarantee for the realization of the filtration and concentration process; in the actual production process, the diameter of the critical equivalent pressure loop should be smaller than the diameter of the drum, so we should reasonably choose the mixing ratio of the inlet pressure and the drum speed to make The flow field filtration process can proceed smoothly, so that the concentration and clarification operation can be completed.

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Choice range of inclination angle of thickener

When the tilt angle is 50 degrees, the concentration efficiency is the highest, and as the tilt angle continues to decrease, the concentration efficiency will gradually increase. When the angle is too low, the concentration efficiency will decrease instead.

The thickening equipment is the source of the water clarification process in the coal preparation plant. The angle of the inclined plate of the inclined plate thickener has a great influence on the efficiency of the thickener. The inclined plate thickener has a bottom feed, and the type of feed is heterogeneous, so it is inclined The angle should be kept between 45-60 degrees, so the test is carried out.

During the test, an inclined plate was added to the ordinary thickener. The inclined plate uses stainless steel bolts to connect the right-click glass plates of different sizes at different angles to form a combination of inclined plates with different inclination angles. At this time, 200g of the well-mixed raw materials can be taken out for a small sieving test to find out the particle size composition. Among them, the 0.045m material content is the highest, indicating that the high ash fine mud content in the coal slime is very high, which has a greater impact on concentration.

The main components of coal slime are kaolinite and illite, as well as a small amount of minerals such as quartz, feldspar and calcite. The two minerals with relatively high content are clay minerals, which will swell when exposed to water and form very fine colloids. , Not easy to settle.

The inclined plate thickener is bottom feeding, and the feeding type is a different flow. Therefore, the range of inclination angles will be about 45~60 degrees. The inclination angles of the inclined plate are selected as 60, 55, 50, and 45 for the test. The results show Because the material is fed at the bottom and the opposite flow enters the inclined plate, taking into account the projected area of ​​the inclined plate and the two factors of discharging, it is more appropriate to choose an angle within the range of 45 to 60 degrees. When you select 60 degrees for the first time, you will find that the inclination angle decreases, and the underflow solids content will increase. Because the projected area increases, the sedimentation area will increase, and the concentration efficiency will increase. When the water flow is non-directional, the particle distribution will be coarse particles in the lower layer and fine particles in the upper layer, which is more conducive to product discharge, but if the fine particles are suspended for too long, they will be lifted away. But when it is at 45 degrees, due to the above reasons, the number of fine particles taken away will increase, the content of overflow solids will increase, and the small efficiency of concentration will decrease instead.

The inclined plate thickener is fed at the bottom, and the type of feeding is heterocurrent, so the selection range of the inclination angle will probably be between 45 and 60 degrees to facilitate the decline of the material; the flow rate is maintained at 2.6 cubic meters per hour, and the concentration It is 50 grams per liter. The test results show that the concentration efficiency is the highest when the tilt angle is 50 degrees. As the inclination angle becomes smaller, the concentration efficiency will gradually increase, but when the angle is too small, the particles in the upper layer will be taken away more and the concentration efficiency will decrease instead.

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A worthy headbox of dual-pressure zone thickener

 The double-pressure zone thickener is mainly used for the washing and concentration of the slurry in the waste paper deinking and reducing treatment system. The machine is mainly composed of active rollers, driven rollers, and endlessly woven filters and flow boxes running around two rollers. , Discharge screw conveyor and other components. The slurry passes through the headbox, which is dewatered by the squeezing action between the filter screen and the active roller in the nip between the filter screen and the active roller. The active roller is engraved with deep grooves, which can obtain a high nip pressure, so that the slurry is concentrated on the inner surface of the mesh into a form of slurry strips. These strips are kept on the filter screen. When the slurry enters the filter In the nip between the net and the movable roller, it will be further dehydrated and then separated from the net surface, falling onto the roller surface and being scraped off and discharged by the scraper. The concentration of the slurry discharged by the machine is constant, and the discharged slurry will be transported away by a screw conveyor, and the removed white water containing ink particles and fillers will be discharged from the bottom of the white water tray.

The double-nip thickener is favored by users because of its good performance, but with the continuous expansion of the wide screen of the filter screen, major problems have become more and more serious; one is the thickness of the slurry layer on the entire web is inconsistent, and the slurry concentration is uneven; the other is The filter is easy to run off, causing the filter to tear. But this will bring great economic losses to the enterprise.

For the problems of the double-pressure thickener, the reasons are as follows:

1. At first, I suspected that the quality of the filter was not good enough; after consulting with the manufacturer of the filter, it was required to strictly follow the technical requirements of the filter. After many experiments, it was proved that the tearing of the filter was not caused by the quality of the filter itself.

2. The sensitivity of the deviation adjustment mechanism is not enough, and the deviation signal cannot be transmitted in time, which will cause the movement of the deviation adjustment motor to lag. By replacing several sets of new control modules, the test is carried out quickly, the deviation adjustment signal is transmitted in time, and the deviation adjustment mechanism moves quickly. The tearing of the filter has little to do with this item.

3. If the machining error of the worm and connecting rod of the two worm gear boxes is too large, the transmission will not be in place and the deviation can not be corrected. Through machining a higher precision worm and connecting rod, the phenomenon of deviation of the filter screen will also occur.

4. If the coaxiality of the two transmission rollers processing fails to meet the requirements or the installation axes of the two rollers are not parallel, vibration will occur, which will cause the filter screen to jump and cause deviation. Re-adjusting the installation accuracy of the two rollers, the effect is still not satisfactory.

It may also be the problem of the headbox. The function of the headbox (1) is that the slurry that is sprayed is evenly distributed along the horizontal direction of the active roller; it effectively disperses the fibers and improves the uniformity of the slurry layer; the spraying is stable. If the pulp output from the headbox is not uniform, the pulp concentration will be uneven, and the filter screen will run off and cause tearing. Therefore, improving the design of the headbox structure is a key issue to solve the problem of the dual-pressure thickener.

After the improvement of the headbox, there are mainly several aspects:

1. In order to ensure that the pressure of the slurry flowing through each section along the way is the same, the sizing main pipe is designed into a square cone pipe with a smaller and smaller cross-sectional area.

2. In order to facilitate the hole arrangement and keep the direction of the slurry flow at the end of the main pipe unchanged, a rectangular tapered pipe of equal width will be used, and the "height ratio" at the entrance is 1:2~3.

3. The main pipe should facilitate the incoming slurry to change the direction of slurry flow. A transition pipe is set between the main pipe and the slurry inlet pipe, and the circular slurry inlet pipe is gradually changed into a rectangular main pipe. The final wall of the slurry inlet pipe and the square cone pipe should be on a horizontal line.

4. Equipped with a return pipe. The function of setting backflow is mainly to ensure the stability of the slurry flow pressure in the branch pipe and the uniform distribution of the slurry. At the same time, there is no dead corner at the end of the cone pipe to prevent the slurry clusters from gathering, expel air bubbles, and play a cleaning role.

5. The main pipe is made of stainless steel, and the inner wall is processed smoothly, without grout or rust. In order to ensure that the main pipe is not deformed, reinforcing ribs are arranged on both sides of the outer wall of the main pipe to make the main pipe have sufficient rigidity.

6. Ensure that the center of gravity of the headbox is on a straight line, which is more conducive to the stability of the headbox.

After the improved design of the headbox, the thickness of the slurry layer on the entire web is uniform, the slurry concentration is basically stable, the service life of the filter is greatly improved, the maintenance cycle of the equipment is reduced, the cost is correspondingly reduced, and the production efficiency of the enterprise is improved.

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A new type of thickener-lifting thickener

 Thickener is a continuous working thickening and clarification equipment, mainly used in the dehydration of tailings slurry in wet beneficiation operations, and also widely used in the thickening and purification of solid-containing slurry such as steel and sewage treatment. According to its driving mode, the thickener can be divided into two categories: peripheral drive thickener and central drive thickener. Peripheral drive thickeners have integral rake lifts to varying degrees, especially the secondary rake in the cone pit. , It will cause the defects of pressure rake. Although the central drive thickener can lift the rake, when the load-bearing bridge is too heavy or the central drive torque is too large, a new type of thickener-automatic rake thickener appears.

When the thickener is working, the motor, reducer and drive transmission equipment rotate along the thickening tank, the transmission device will drive the central support through the transmission bridge and the central support, and the rotating support will drive the sliding frame through the sliding key , The sliding frame is connected to the rotating cage, and the long and short handles and the vice handles are driven by the rotating cage. The rake teeth of the long and short rake racks will scrape the sedimentation material in the thickening tank into the cone pit of the thickening tank, and the role of the vice handle will prevent the cone. The underflow material in the pit is consolidated to ensure the smooth flow of underflow sludge.

When the material settled to the bottom of the thickening tank increases, when the bed layer thickens, the working resistance of the rake will increase. When the working resistance is adjusted to a set value, the transmission device will stop rotating and the rake cylinder will be lifted. Drive the sliding frame, the whole will be lifted up, and the working resistance will be reduced subsequently, but if it is reduced to a certain level, the rake will not be lifted, and the rake frame will stay at this height for rotating work until the lowest When the working resistance increases to the set value again, the rake frame will be raised again, repeating the action, so as to achieve the purpose of automatically raising and lowering the rake.

Peripheral transmission automatic rake-lifting thickener includes transmission device, center support, transmission bridge frame, rotating cage, long and short rake frame vice handle, distribution device, trough frame, hydraulic system, electronic control system, etc.

(1) Transmission device.

The transmission device can be driven by a motor reducer or a sub-motor. The transmission mode can be a rubber wheel, a knurled wheel or a gear drive to meet different work needs.

(2) Center support

The central support is a composite structure, composed of a fixed support, a sliding frame, a rotating bracket, and a seat ring. The transmission device drives the central support to rotate through the rotating bridge frame. When the rake is lifted, the hydraulic cylinder will lift the central support sliding frame to make the whole Lifting, so that it can not only show the driving torque, but also can lift part of the lifting according to needs, the structure is more novel.

(3) Transmission bridge

One end of the transmission bridge is connected with the central support rotating bracket, and one end is connected with the transmission device. However, because the central support adopts a specific device, the bridge does not move laterally with the lifting part of the thickener, which prevents the transmission device from being in the center. It can increase the axial force generated when part of the lifting, avoiding the phenomenon of rubber wheel degumming. Determine the transmission mode and other transmission modes.

(4) Extraction of automatic rake signal

There are two ways to extract the rake signal of the thickener. One is an independent mud control resistance detection device. It is mainly composed of force measuring box and sensor. The force measuring device is installed on the mud scraper near the cone pit. During the operation of the equipment, the force receiver directly contacts the deposited sludge. During the operation of the equipment, the force receiver directly contacts the sludge. The resistance during mud scraping is transmitted by the secondary instrument to the PLC controller of the control system. A pressure sensor, hydraulic pump and various control valves are installed in the hydraulic pump station. The mud scraping resistance is detected by the pressure sensor. The hydraulic signal will be converted into an electric signal, and the PLC program controller will issue an instruction, so that the rake lifting cylinder can move and realize automatic rake lifting.

(5) Cloth device

Ordinary center drive thickener feeds the material directly from the center of the pool. The particles in the slurry can’t settle sufficiently. The sedimentation layer that has been deposited is destroyed due to the erosion of the liquid flow, and the material that has been deposited is removed. Rushing affects not only the concentration of overflow water, but also the sedimentation effect of particles.

The peripheral drive center automatic rake-lifting thickener combines the advantages of a peripheral drive thickener and a central drive thickener. This machine not only has the advantage of large transmission output torque of the peripheral drive thickener, but also has the central drive thickener that can lift the rake as a whole It also avoids the thickening machine from being too bulky. Therefore, the large-scale and intelligent thickening machine can be realized, which is a direction of the thickening machine.

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How to use inclined plate thickener for tailings dry discharge

 Tailings treatment is an important part of mine production. Concentration in dry tailings discharge is an important link in achieving dry stacking. It not only directly affects the processing capacity of filter equipment, but also affects the resistance of filter cakes. The particle is resistive to the filter cake, so according to the characteristics of iron tailings, there is a new type of thickener.

The flow of tailings slurry in the thickener is ideally slow. As soon as the solid particles leave the flow layer, they will be considered as sediment. This model is also called shallow sedimentation. The sedimentation occurs in the void between the inclined plates. Within the cavity, but due to the small spacing between the inclined plates, it creates favorable conditions for the formation of laminar flow. The clarified overflow water moves upward along the inclined plate space, and the solid particles settle between the two plates, and only need to settle to a small distance to fall on the plate, and then slide down the inclined plate to the compression port for compression and dehydration , The final height will be discharged from the bottom discharge port. According to the difference between the feeding direction and the sedimentation direction of solid particles in the inclined plate thickener, it can be divided into upward flow and downward flow. Three types of lateral flow.

(1) Upward flow means that tailings slurry is fed from the lower part, the sediment is discharged from the lower part, and the overflow is discharged from the upper part;

(2) Downward flow means that tailings slurry is fed from the upper part, the sediment is discharged from the lower part, and the overflow is discharged from the lower part;

(3) Lateral flow means that tailings slurry is fed in from one side, sediments are discharged from the bottom, and overflow is discharged from the other side.

Since the concentration of iron tailings is generally low, the thickener is equivalent to a clarification device. Its sedimentation area can be calculated based on the rising speed of the clarified water in the thickener and the sedimentation speed of the finest particles in the material to be recovered. 

The inclination angle of the inclined plate is also an important concentration parameter. The sum of the area of ​​the thickener is the sum of the horizontal projection area of ​​each layer of the inclined plate. In a certain range, when the inclination angle is less than a range, the relative sedimentation velocity of solid particles will be reduced, and the liquid flow between the inclined plates will be affected. In order to work normally, the solid particles falling on the inclined plates can flow by themselves. The discharge angle cannot be too small. So choose 45 degrees-60 degrees.

The spacing between the plates has a great influence on the concentration effect. When the distance between the plates is small but the production capacity is the same, the size of the thickener will be too small. The distance between the plates is small, and a large number of inclined plates can be accommodated on the same level, which can help increase the sedimentation area of ​​the thickener. However, if the board spacing is too small, the surface of the inclined board will rub against the fixed particles that have fallen on the board from sliding down, and bring certain difficulties to the use and maintenance of the equipment.

The core key to the promotion and application of inclined plate concentration equipment lies in the material selection and production of the inclined plate. The range of material selection is relatively wide, and the best can be selected according to the conditions of use. Board materials with the characteristics of chemical stability, sufficient strength, light weight and cheapness, non-toxicity, smooth surface, good hydrophobicity, antistatic, and aging resistance can all be used.

If the conditions of use allow, the length of the inclined plate is longer to increase the unit footprint of the thickener.

At the same time, in order to ensure that the material can be evenly covered in the width direction and to avoid the deflection and deformation of the board surface in normal work, the width of the board should not be too large, usually no more than 0.8 meters.