Tailing treatment cement separation method

Abstract

A cement separation method for tailing treatment belongs to the field of tailing treatment and comprises the following steps: step 1, adding a flocculant into a flocculation basin for flocculation operation; 2, after flocculation is completed, upper clear liquid of the flocculation basin is pumped out through a water pump and filtered through a filter screen, and filtrate is recycled; step 3, pumping slurry deposited at the lower part of the flocculation basin into a plate-and-frame filter press through a high-pressure injection pump and an auxiliary pipeline; 4, the slurry enters from two corner holes in the filter plate, penetrates through the filter cloth and is discharged from open flow water nozzles on the two sides of the filter plate; 5, along with the increase of the feeding pressure, when the pressure reaches a set value, the high-pressure injection pump stops working, the feeding process is finished, filter pressing is completed after residual water is squeezed out, and clean water obtained after filter pressing is stored in a clean water tank; 6, after filter pressing is completed, a filter cake is recycled, filter cloth is cleaned, and then filter pressing operation is conducted again. According to the method, the comprehensive efficiency and the resource recovery rate of tailing cement separation are improved by optimizing the flocculating agent and treatment operation.

Description

Technical Field

[0001] This invention belongs to the field of tailings treatment, specifically a method for separating cement from tailings. Background Technology

[0002] Tailings are waste generated during ore mining and processing. Their composition is complex, typically containing large amounts of water, soil, and ore fragments. Direct discharge or accumulation not only occupies significant land resources but also risks rainwater runoff causing harmful substances to seep into the soil and groundwater, resulting in severe environmental pollution. Furthermore, the failure to effectively recover usable components such as cement from tailings also leads to resource waste. However, current tailings slurry treatment typically uses a single flocculant, resulting in poor flocculation efficiency. Moreover, after flocculation, the slurry in the flocculation tank is directly discharged... Summary of the Invention

[0003] This invention provides a method for separating cement from tailings, thereby overcoming the deficiencies in the prior art.

[0004] This invention is achieved through the following technical solution: A method for separating cement from tailings treatment includes the following steps: Step 1: Transfer the tailings slurry into the flocculation tank and add flocculant to carry out flocculation. Step 2: After flocculation is completed, the clear liquid at the top of the flocculation tank is pumped out by a water pump and filtered through a filter screen. The filtrate is then recycled. Step 3: The slurry deposited at the bottom of the flocculation tank is injected into the plate and frame filter press through a high-pressure injection pump and auxiliary pipelines; Step 4: The slurry enters through the two upper corner holes of the filter plate, passes through the filter cloth, and exits from the visible water nozzles on both sides of the filter plate; Step 5: As the feeding pressure increases, the feeding amount decreases. When the pressure reaches the set value, the high-pressure injection pump stops working, the feeding process ends, the remaining water is squeezed out, the filtration is completed, and the filtered water is stored in the clean water tank. Step 6: After the filter press is completed, the filter cake is recovered and the filter cloth is cleaned before performing the filter press operation again.

[0005] The tailings treatment cement separation method described above, wherein the flocculant in step one comprises the following substances in parts by weight: 30-40 parts polyacrylamide, 20-30 parts polyaluminum chloride, and 15-25 parts polysilicate ferric sulfate aluminum sulfate.

[0006] In the tailings treatment cement separation method described above, the amount of flocculant added is 0.5-0.7 g / L. After the flocculant is added, the mixture is stirred at a speed of 200-300 r / min for 5-7 min, and then allowed to stand for 30-45 min to allow the flocculated solids to settle.

[0007] In the tailings treatment and cement separation method described above, the filter screen in step two has a mesh size of 200 mesh. The filter screen is disassembled and cleaned once a day to prevent the filter holes from becoming clogged and affecting the filtration efficiency.

[0008] In the tailings treatment cement separation method described above, in step three, before the slurry is injected, the hydraulic pump station of the plate and frame filter press is started, the oil cylinder gradually moves forward, pressing the filter plates together in sequence, forming a sealed cavity between the filter plates, and at the same time the flap closes. The working pressure range of the high-pressure injection pump is 1.5-2.5MPa, the diameter of the auxiliary pipeline is 50-80mm, and the pipeline connection is sealed with a sealing flange to prevent slurry leakage.

[0009] In the tailings treatment cement separation method described above, in step four, the pressing water tank of the plate and frame filter press stores clean water. The pressing pump pumps the clean water into the cavity of the diaphragm filter plate. As the cavity gradually fills with clean water, the pressure gradually increases, thereby squeezing the filter cake in the chamber. The moisture content of the filter cake gradually decreases. The pressing pump continuously flushes water into the diaphragm plate at a constant pressure, continuously squeezing the filter cake. The water in the filter cake flows out through the open water nozzle.

[0010] In the tailings treatment and cement separation method described above, the pressure setting value in step five is 0.8-1.2 MPa.

[0011] In the tailings treatment cement separation method described above, after pressing in step five, the clean water in the cavity of the diaphragm filter plate is pumped back to the pressing water tank by the pressing pump to complete the recovery of pressing water. Subsequently, the hydraulic pump station drives the oil cylinder to retract, the filter plates are released one by one, the flip plate is automatically flipped, and the dewatered filter cake is unloaded from between the filter plates to the conveying device below, realizing the automatic unloading of the filter cake.

[0012] In the tailings treatment cement separation method described above, after unloading, the filter press is emptied and backflushed to blow off the fine particles and impurities remaining on the surface of the filter cloth, so as to avoid clogging the filter cloth pores and affecting the subsequent filtration effect. The backflushing operation takes 20-40 seconds and is repeated 2-3 times.

[0013] As described above, in a tailings treatment cement separation method, the specific operation of the backflushing is as follows: the air compressor fills the air storage tank with compressed air, maintaining a pressure of 0.8±0.05MPa. When backflushing is required, the control system automatically switches to the blowing function. Compressed air can enter the feed channel of the filter press from the pressing plate, causing the unfiltered slurry with high water content in the central feed pipe to flow back to the flocculation tank, thereby reducing slurry leakage when the filter plates are pulled open for unloading. At the same time, when multiple filter presses are running simultaneously, their filtration cycle intervals can be set, and backflushing can be performed alternately to improve the backflushing efficiency of a single set of backflushing equipment.

[0014] The advantages of this invention are: This invention effectively improves flocculation and sedimentation efficiency by using a flocculant composed of polyacrylamide, polyaluminum chloride, and polysilicic acid ferric sulfate and aluminum sulfate. The long-chain molecular structure of polyacrylamide can form a bridging effect, aggregating small particles into larger flocs. Polyaluminum chloride enhances the electrostatic neutralization ability between particles due to its high charge density. The polysilicic acid ferric sulfate and aluminum sulfate compound can further optimize the density and sedimentation speed of the flocs. The synergistic effect of the three not only shortens the treatment time but also reduces the dosage of the agents. At the same time, it has strong adaptability to water quality with different pH ranges, solving the problem of unstable treatment effect of single flocculants under complex water quality conditions. In this invention, the supernatant is extracted after flocculation and sedimentation, thereby reducing the feed volume of the plate and frame filter press. This effectively reduces the load on the plate and frame filter press during operation, extends the service life of the equipment, and reduces energy consumption caused by high throughput. Simultaneously, the early extraction of the supernatant increases the concentration of material entering the plate and frame filter press, which helps to improve the formation speed and quality of the filter cake during subsequent filtration, reduces the moisture content in the filter cake, and thus improves the overall solid-liquid separation efficiency, creating more favorable conditions for subsequent material processing or resource recovery. This invention improves the overall efficiency and resource recovery rate of tailings cement separation by optimizing flocculants and processing operations. In the flocculation stage, precise control of the flocculant ratio, dosage, and stirring / settling parameters allows cement particles and impurities in the tailings slurry to form stable, rapidly settling flocs, effectively solving the problem of low separation efficiency caused by incomplete flocculation and slow settling speed in traditional methods. In the filter press stage, by optimizing the hydraulic system pressure setting, feeding process, and backflushing cleaning operation of the plate and frame filter press, not only is the dewatering effect of the filter cake improved and the moisture content of the filter cake reduced, but filter cloth clogging is also reduced, extending the service life of the filter cloth and lowering equipment maintenance costs. Simultaneously, the design of supernatant recovery and filter press water recycling achieves efficient reuse of water resources, reducing the consumption of clean water. The filtered water can also be used as clean water, thus saving water resources and meeting the industrial development requirements of energy conservation, emission reduction, and resource recycling, resulting in both economic and environmental benefits. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] A method for separating cement from tailings treatment includes the following steps: Step 1: Transfer the tailings slurry into the flocculation tank and add flocculant to carry out flocculation. Step 2: After flocculation is completed, the clear liquid at the top of the flocculation tank is pumped out by a water pump and filtered through a filter screen. The filtrate is then recycled. Step 3: The slurry deposited at the bottom of the flocculation tank is injected into the plate and frame filter press through a high-pressure injection pump and auxiliary pipelines; Step 4: The slurry enters through the two upper corner holes of the filter plate, passes through the filter cloth, and exits from the visible water nozzles on both sides of the filter plate; Step 5: As the feeding pressure increases, the feeding amount decreases. When the pressure reaches the set value, the high-pressure injection pump stops working, the feeding process ends, the remaining water is squeezed out, the filtration is completed, and the filtered water is stored in the clean water tank. Step 6: After the filter press is completed, the filter cake is recovered and the filter cloth is cleaned before performing the filter press operation again.

[0017] Specifically, the flocculant in step one of this embodiment includes the following components by weight: 30-40 parts polyacrylamide, 20-30 parts polyaluminum chloride, and 15-25 parts polysilicate ferric sulfate aluminum sulfate. In practical applications, the proportions of each component can be finely adjusted according to the differences in cement content in the tailings slurry. When the cement particle content is high, the proportion of polyacrylamide can be appropriately increased to 35-40 parts to enhance the bridging flocculation effect; if there are many fine suspended impurities in the slurry, the amount of polyaluminum chloride added can be adjusted to 25-30 parts to improve the electrostatic neutralization capacity.

[0018] In the tailings treatment cement separation method described above, the flocculant is added at a rate of 0.5-0.7 g / L. After adding the flocculant, the mixture is stirred at a speed of 200-300 r / min for 5-7 minutes, followed by standing for 30-45 minutes to allow the flocculated solids to settle. During the stirring process, it is necessary to ensure that the stirring blades are completely immersed below the surface of the tailings slurry, and that the stirring range covers the entire cross-section of the flocculation tank to avoid uneven flocculation due to excessively high or low local flocculant concentrations. During the standing stage, the environment around the flocculation tank must be kept stable to avoid external vibrations or water flow impacts affecting the floc settling process. The height of the settling interface can be monitored by observing the scale lines on the side wall of the flocculation tank. When there is no significant change in the settling interface within 20 minutes, the settling process is considered complete.

[0019] More specifically, in step two of this embodiment, the filter screen has a mesh size of 200 mesh, and the filter screen is disassembled and cleaned once a day to prevent the filter holes from becoming clogged and affecting the filtration efficiency.

[0020] More specifically, in step three of this embodiment, the hydraulic pump station of the plate and frame filter press is started before the slurry is injected. The oil cylinder gradually moves forward, pressing the filter plates together in sequence, forming a sealed cavity between the filter plates. At the same time, the flap closes. The working pressure range of the high-pressure injection pump is 1.5-2.5MPa, the diameter of the auxiliary pipeline is 50-80mm, and the pipeline connections are sealed with sealing flanges to prevent slurry leakage. In actual operation, the hydraulic oil level and quality of the hydraulic pump station must be checked first to ensure that the oil level is between 1 / 2 and 2 / 3 of the mark on the oil tank, and that the oil is clear, free of impurities, and free of emulsification. If the hydraulic oil is found to be cloudy or contains particulate matter, the hydraulic oil must be replaced and the oil tank cleaned in time. During the filter plate pressing process, the forward speed of the hydraulic cylinder should be monitored in real time and controlled at 5-8 mm / s to avoid damage to the filter plates due to excessive speed. Simultaneously, the pressing pressure between the filter plates should be fed back in real time via a pressure sensor. When the pressure reaches a specified value, the hydraulic pump station automatically switches to pressure-holding mode to maintain the airtightness between the filter plates. The filter cloth installation must ensure it is flat and wrinkle-free, with the edges tightly fitted to the sealing surface of the filter plate. It should be fixed to the filter plate using its own buckles or straps to prevent displacement of the filter cloth during pressing, which could lead to short-circuit leakage of the slurry. For the filter cloth material, high-strength polyester needle-punched felt is recommended. It features resistance to acid and alkali corrosion, good wear resistance, and high filtration accuracy, effectively trapping cement particles in the slurry while ensuring good water permeability and extending the filter cloth replacement cycle. The typical service life of the filter cloth is 3-6 months, but the specific replacement time needs to be determined based on the actual filtration effect and the wear condition of the filter cloth. When the filter cloth surface shows obvious damage, holes, or the filtration speed drops below 60% of the initial value, it should be replaced promptly.

[0021] More specifically, in step four of this embodiment, the pressing water tank of the plate and frame filter press stores clean water. The pressing pump pumps the clean water into the cavity of the diaphragm filter plate. As the cavity gradually fills with clean water, the pressure gradually increases, thereby squeezing the filter cake in the chamber. The moisture content of the filter cake gradually decreases. The pressing pump continuously flushes water into the diaphragm plate at a constant pressure and continuously squeezes the filter cake. The water in the filter cake flows out through the open water nozzle. During the pressing process, the working pressure of the pressing pump must be strictly controlled to maintain a constant pressure of 1.2-1.5 MPa, with pressure fluctuations not exceeding ±0.1 MPa, to ensure that the filter cake receives uniform and stable extrusion pressure. The clean water in the pressing tank needs to be pre-treated to remove suspended impurities and calcium and magnesium ions, preventing impurities from clogging the pressing pump pipeline or forming scale in the diaphragm filter plate cavity, which would affect the pressing effect and the service life of the diaphragm. At the same time, the unobstructed flow of the open-flow nozzle should be checked regularly. If the water flow rate is found to be significantly slowed down or interrupted, the machine should be stopped immediately to clean any remaining filter cake debris in the nozzle, ensuring that the pressed water can be discharged smoothly. The pressing time can be adjusted according to the thickness of the filter cake and the initial moisture content, generally controlled at 20-30 minutes. When the water flow rate discharged from the open-flow nozzle is less than 0.5 L / min for 5 consecutive minutes, the pressing process can be considered complete.

[0022] Furthermore, the pressure setting value in step five of this embodiment is 0.8-1.2 MPa.

[0023] Furthermore, in step five of this embodiment, after pressing, the clean water in the cavity of the diaphragm filter plate is pumped back to the pressing water tank by the pressing pump, completing the recovery of the pressing water. Subsequently, the hydraulic pump station drives the oil cylinder to retract, the filter plates are released one by one, and the flip plate automatically flips over, unloading the dehydrated filter cake from between the filter plates to the conveying device below, realizing automatic unloading of the filter cake. The conveying device adopts a belt conveyor, and its conveying speed can be adjusted according to the amount of filter cake unloaded, usually controlled at 1.0-1.5m / s. The surface of the conveyor is equipped with anti-slip patterns to prevent the filter cake from slipping during the conveying process. The filter cake is conveyed by the conveyor to the designated filter cake stacking area. The stacking height should not exceed 2m to avoid secondary agglomeration of the filter cake due to gravity compression, which would affect the subsequent resource utilization.

[0024] Furthermore, in step six of this embodiment, after unloading, the filter press is emptied and a backflushing operation is performed to blow off the fine particles and impurities remaining on the surface of the filter cloth, so as to avoid clogging the filter cloth pores and affecting the subsequent filtration effect. The backflushing operation takes 20-40 seconds and is performed 2-3 times.

[0025] Furthermore, the specific operation of the backflushing operation described in this embodiment is as follows: the air compressor fills the air tank with compressed air, maintaining a pressure of 0.8±0.05MPa. When backflushing is required, the control system automatically switches to the blowing function. Compressed air can enter the feed channel of the filter press from the pressing plate, causing the unfiltered slurry with high moisture content in the central feed pipe to flow back to the flocculation tank, thereby reducing slurry leakage when the filter plates are pulled open for unloading. Simultaneously, when multiple filter presses are running at the same time, their filtration cycle intervals can be set, and backflushing can be performed alternately to improve the backflushing efficiency of a single set of backflushing equipment. In practical applications, the operating status of the air compressor must be checked before the backflushing operation to ensure that its output air pressure is stable within the set range. The safety valve of the air tank needs to be calibrated regularly to ensure that it can automatically release pressure when the pressure exceeds the upper limit, preventing equipment damage due to overpressure. Before entering the feed channel, the compressed air must pass through a precision filter to remove oil and moisture from the air, preventing oil stains from adhering to the filter cloth surface and affecting the filtration accuracy, or moisture from causing secondary wetting of the filter cake. For alternating backflushing control of multiple filter presses, the filter press cycle parameters of each device can be preset through the PLC control system. The backflushing command is automatically triggered according to the equipment operation progress. During the backflushing process, the backflushing pressure and time are monitored in real time. When the single backflushing pressure is lower than 0.75MPa or higher than 0.85MPa, the system automatically alarms and suspends the backflushing operation. It restarts after the pressure returns to normal, ensuring the stability and consistency of the backflushing effect.

[0026] After three months of tailings slurry treatment using the tailings treatment and cement separation method of this invention, compared with the previous three months using traditional methods, the tailings slurry treatment volume increased by more than 15%, the filter cake moisture content decreased to more than 10%, the water resource recycling rate increased to more than 85%, and approximately 300-500 tons of clean water were saved per month. Simultaneously, due to the effective control of filter cloth clogging, the continuous operating time of the plate and frame filter press was extended to 8-10 hours per batch, the equipment maintenance frequency decreased by more than 50%, and the overall treatment cost decreased by more than 10%. Regarding slurry resource recovery, after treatment using this method, the cement content in the filter cake is significantly reduced. The recovery rate of the components reaches 88%-92%, and the recovered cement can be reused in building materials or mine backfilling operations, realizing efficient recycling of resources. At the same time, the solid content of the clear water filtered from the supernatant of the flocculation tank and the clear water filtered from the plate and frame filter press is controlled below 0.05g / L. The water quality is clear and transparent, and can be directly reused in the washing of tailings conveying pipelines, flocculant dissolution and preparation, and cleaning of the plant area, further reducing the dependence on fresh water sources. Therefore, the tailings treatment cement separation method of the present invention can effectively realize resource recovery and utilization while ensuring cement separation efficiency, thus playing a good economic role.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for separating cement from tailings, characterized in that: Includes the following steps: Step 1: Transfer the tailings slurry into the flocculation tank and add flocculant to carry out flocculation. Step 2: After flocculation is completed, the clear liquid at the top of the flocculation tank is pumped out by a water pump and filtered through a filter screen. The filtrate is then recycled. Step 3: The slurry deposited at the bottom of the flocculation tank is injected into the plate and frame filter press through a high-pressure injection pump and auxiliary pipelines; Step 4: The slurry enters through the two upper corner holes of the filter plate, passes through the filter cloth, and exits from the visible water nozzles on both sides of the filter plate; Step 5: As the feeding pressure increases, the feeding amount decreases. When the pressure reaches the set value, the high-pressure injection pump stops working, the feeding process ends, the remaining water is squeezed out, the filtration is completed, and the filtered water is stored in the clean water tank. Step 6: After the filter press is completed, the filter cake is recovered and the filter cloth is cleaned before performing the filter press operation again.

2. The method for separating cement from tailings according to claim 1, characterized in that: The flocculant in step one comprises the following substances in parts by weight: 30-40 parts polyacrylamide, 20-30 parts polyaluminum chloride, and 3-5 parts ferric sulfate polysilicate.

3. The method for separating cement from tailings according to claim 1, characterized in that: The amount of flocculant added is 0.5-0.7 g / L. After the flocculant is added, the mixture is stirred at a speed of 200-300 r / min for 5-7 min, and then allowed to stand for 30-45 min to allow the flocculated solids to settle.

4. The method for separating cement from tailings according to claim 1, characterized in that: The filter screen in step two has a mesh size of 200. The filter screen is disassembled and cleaned once a day to prevent the filter holes from becoming clogged and affecting the filtration efficiency.

5. The method for separating cement from tailings according to claim 1, characterized in that: In step three, the hydraulic pump station of the plate and frame filter press is started before the slurry is injected. The oil cylinder moves forward gradually, pressing the filter plates together in sequence to form a sealed cavity between the filter plates. At the same time, the flap closes. The working pressure range of the high-pressure injection pump is 1.5-2.5MPa, the diameter of the auxiliary pipeline is 50-80mm, and the pipeline connection is sealed with a sealing flange to prevent slurry leakage.

6. The method for separating cement from tailings according to claim 1, characterized in that: In step four, the pressing water tank of the plate and frame filter press stores clean water. The pressing pump pumps the clean water into the cavity of the diaphragm filter plate. As the cavity gradually fills with clean water, the pressure gradually increases, thereby squeezing the filter cake in the chamber. The moisture content of the filter cake gradually decreases. The pressing pump continuously flushes water into the diaphragm plate at a constant pressure and continuously squeezes the filter cake. The water in the filter cake flows out through the open water nozzle.

7. The method for separating cement from tailings according to claim 1, characterized in that: The pressure setting value in step five is 0.8-1.2 MPa.

8. The method for separating cement from tailings according to claim 1, characterized in that: After pressing in step five, the clean water in the cavity of the diaphragm filter plate is pumped back to the pressing water tank by the pressing pump to complete the recovery of the pressing water. Then, the hydraulic pump station drives the oil cylinder to retract, the filter plates are released one by one, the flip plate is automatically flipped, and the dehydrated filter cake is unloaded from between the filter plates to the conveying device below, realizing the automatic unloading of the filter cake.

9. A method for separating cement from tailings according to claim 1, characterized in that: After unloading is completed in step six, the filter press is emptied and a backflushing operation is performed to blow off the fine particles and impurities remaining on the surface of the filter cloth, so as to avoid clogging the pores of the filter cloth and affecting the subsequent filtration effect. The backflushing operation takes 20-40 seconds and is performed 2-3 times.

10. A method for separating cement from tailings according to claim 9, characterized in that: The specific operation of the backflushing is as follows: the air compressor fills the air tank with compressed air and maintains the pressure at 0.8±0.05MPa. When backflushing is required, the control system will automatically switch to the blowing function. The compressed air can enter the feed channel of the filter press from the pressing plate, so that the unfiltered slurry with high water content in the central feed pipe flows back to the flocculation tank, so as to reduce the leakage of slurry when the filter plate is pulled open for unloading. At the same time, when multiple filter presses are running simultaneously, their filtration cycle intervals can be set, and backflushing can be carried out alternately to improve the backflushing efficiency of a single set of backflushing equipment.