Water and reagent recycling system and method for fly ash flotation production line

Abstract

The application discloses a kind of water and reagent recycling system and method for fly ash flotation production line, it is related to flotation system technical field, system includes: three-stage circulating water pool, coal vacuum dehydrator, ash vacuum dehydrator, coal washing water tank, ash washing water tank, one two-stage circulating water sedimentation tank and ash slurry concentration equipment;Coal vacuum dehydrator and the washing water of ash vacuum dehydrator generated are three-stage circulating water and are discharged into three-stage circulating water pool, wait for use, different grades circulating water in circulating water pool are used in each water equipment in flotation process, the vacuum valve effluent of coal vacuum dehydrator generated is discharged to coal washing water tank storage and wait for use, the vacuum valve effluent of ash vacuum dehydrator generated is discharged to ash washing water tank storage and wait for use, the circulating water of coal washing water tank storage is recycled to coal vacuum dehydrator as washing water, the circulating water of ash washing water tank storage is recycled to ash vacuum dehydrator as washing water.The application can reduce the water treatment cost of wet separation processing fly ash.

Description

Technical Field

[0001] This invention relates to the field of flotation system technology, and in particular to a water and reagent recycling system and method for use in a fly ash flotation production line. Background Technology

[0002] Fly ash is a fine solid particle collected by the dust removal system in thermal power plants that use pulverized coal as fuel. Due to technical problems in previous years, the unburned carbon content in fly ash is between 8% and 20%. Because of this high unburned carbon content, comprehensive utilization of fly ash is difficult, and large-scale reuse is not possible. Therefore, most of it is stockpiled in wet form. Currently, the main separation methods are dry separation and wet separation, with wet separation being more effective than dry separation.

[0003] Wet flotation requires a large amount of water, and in traditional production processes, water resources are often recycled to ensure efficient use. However, in existing fly ash flotation processes, the use of recycled water presents several problems: the flotation effect gradually decreases over time, specifically, the quality of the clean ash initially decreases and then increases, while the quality of the clean coal continues to decline. The common explanation is the presence of residual reagents in the recycled water and the accumulation of fine particles from each stage of the process. To eliminate these negative effects, sedimentation and purification are often necessary. In the past, the recycled water underwent centralized sedimentation treatment, with each stream flowing into a circulating sedimentation tank. However, in wet fly ash flotation, the water required is approximately 4-8 times the amount of fly ash to be treated. This large water demand, coupled with stringent water quality requirements, makes the treatment of the recycled water crucial. Such a large volume of recycled water represents a significant increase in treatment costs, often requiring large sedimentation tanks and substantial manpower and time for subsequent treatment of the sludge and fly ash in the sedimentation tanks. This also results in a waste of resources. Furthermore, in wet fly ash separation, a large number of devices, such as slurry pumps and vacuum dewatering machines, require clean water to complete their functions. The water used here has high requirements for water quality. If clean water is used, the amount of water used will increase, and the increase in clean water will often lead to an increase in the amount of circulating water, which in turn leads to the discharge of wastewater. If circulating water is used, it needs to be subjected to a higher degree of sedimentation and purification, which further increases the cost. Summary of the Invention

[0004] The purpose of this invention is to provide a water and reagent recycling system and method for a fly ash flotation production line, so as to solve the problems existing in the prior art and reduce the cost of wet separation of fly ash.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides a water and reagent recycling system for a fly ash flotation production line, comprising: a three-stage circulating water tank, a coal vacuum dewatering machine, an ash vacuum dewatering machine, a coal washing water tank, an ash washing water tank, primary and secondary circulating water sedimentation tanks, and an ash slurry thickening device; the washing water generated by the coal vacuum dewatering machine and the ash vacuum dewatering machine is tertiary circulating water and discharged into the three-stage circulating water tank for later use; the tertiary circulating water stored in the three-stage circulating water tank is reused in the water-using equipment of the flotation process; the vacuum valve generated by the coal vacuum dewatering machine... Water is discharged into the coal washing water tank for storage and later use. Water from the vacuum valve of the ash vacuum dewatering machine is discharged into the ash washing water tank for storage and later use. The circulating water stored in the coal washing water tank is reused in the coal vacuum dewatering machine as washing water. The circulating water stored in the ash washing water tank is reused in the ash vacuum dewatering machine as washing water. The overflow water from the ash slurry thickening equipment is discharged into the primary and secondary circulating water sedimentation tanks for sedimentation treatment. The effluent from the primary and secondary circulating water sedimentation tanks after sedimentation treatment is reused in the water purification equipment.

[0007] Preferably, the overflow port of the coal washing water tank is connected to the tertiary circulating water pool; the overflow port of the ash washing water tank is connected to the primary and secondary circulating water sedimentation pools.

[0008] Preferably, the solid content in the tertiary circulating water is >5‰; the solid content in the secondary circulating water is 0.5‰-5‰; and the solid content in the primary circulating water is <0.5‰.

[0009] Preferably, the water purification equipment includes one or more of the following: a slurry mixing tank, a collector emulsifier, a foaming agent emulsifier, a flocculant hydrolysis device, a slurry pump, a sealing water tank for a coal vacuum dewatering machine, and a water tank for a coal vacuum pump. The sealing water tank for the coal vacuum dewatering machine is used to store the sealing water for the coal vacuum dewatering machine and the coal vacuum dewatering machine. The vacuum pump used in the coal vacuum dewatering machine and the coal vacuum dewatering machine is a water ring vacuum pump. The water tank for the coal vacuum pump is used to store the water for the water ring vacuum pump.

[0010] Preferably, the three-stage circulating water tank is equipped with a stirring device to prevent the sedimentation of fixed particles.

[0011] Preferably, the primary and secondary circulating water sedimentation tanks are multi-stage sedimentation tanks, and the solid content of the effluent is less than 0.05‰.

[0012] The present invention also provides a method for recycling water and reagents in a fly ash flotation production line, comprising: identifying the source of circulating water at each point during the fly ash flotation process;

[0013] The circulating water is classified into different grades based on the content of solid particles, the proportion of fine particles, and the type of fine particles.

[0014] Different types of circulating water require different treatments to ensure the rational utilization of each part of the circulating water.

[0015] Preferably, the circulating water is classified as follows: water with a solid-liquid ratio of <0.5‰ is primary circulating water, water with a solid-liquid ratio of 0.5‰-5‰ is secondary circulating water, and water with a solid-liquid ratio of >5‰ is tertiary circulating water.

[0016] Preferably, the tertiary circulating water is reused in the flotation process water equipment to fully recover the solid particles. The primary and secondary circulating water are further divided into primary and secondary circulating water with coal particles and primary and secondary circulating water with ash particles, depending on the type of fine particles. The primary and secondary circulating water with coal particles is circulated to the coal vacuum dewatering machine for reuse as flushing water and discharged to the tertiary circulating water tank for direct use. The primary and secondary circulating water with ash particles is circulated to the ash vacuum dewatering machine for reuse as flushing water and discharged to the primary and secondary circulating water sedimentation tank for sedimentation treatment.

[0017] Preferably, the purified water obtained from the sedimentation treatment in the primary and secondary circulating water sedimentation tanks is reused in the purified water equipment.

[0018] The present invention achieves the following technical effects compared to the prior art:

[0019] The flushing water produced by the coal vacuum dewatering machine and ash vacuum dewatering machine in this invention is tertiary circulating water. It contains a relatively high amount of solid particles and needs to be recycled. Specifically, the water in the tertiary circulating water tank is reused in the flotation process equipment for further flotation. The vacuum valve effluent from the coal vacuum dewatering machine and ash vacuum dewatering machine is secondary circulating water. This secondary circulating water can be reused in the coal vacuum dewatering machine and ash vacuum dewatering machine as flushing water. Excess secondary circulating water is discharged to the tertiary circulating water tank and the primary and secondary circulating water sedimentation tanks for further utilization. The water after sedimentation treatment in the primary and secondary circulating water sedimentation tanks has an extremely low solid particle content and can be reused as clean water in water purification equipment with high water requirements, thereby reducing the input of external clean water and lowering the cost of clean water usage.

[0020] This invention classifies and categorizes circulating water based on the content of solid particles, the proportion of fine particles, and the type of fine particles. Then, according to different levels and types, the circulating water is reused in different water-using equipment, which can reduce the cost of the flotation process.

[0021] The specific analysis is as follows: circulating water containing a high proportion of fine coal particles can be recycled; vacuum filtration water and overflow water from ash slurry thickening equipment containing a high proportion of fine ash particles must undergo sedimentation treatment before reuse; and filter cloth rinsing water from vacuum dewatering machines with moderately fine ash particles can also be directly recycled. This classification and reuse of circulating water not only reduces settling costs but also shortens the circulating water cycle time. Furthermore, frothers have a limited effective time during flotation. Large-volume sedimentation tanks and other purification devices can cause the reagents in the circulating water to exceed their effective time or separate out of the circulating water. By shortening the circulating water cycle time, the residual frother in the circulating water significantly reduces the dosage required for subsequent use, allowing the reagent usage in continuous flotation processes to reach less than 50% of the normal dosage. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a structural block diagram of a water and reagent recycling system for a fly ash flotation production line provided in an embodiment of the present invention;

[0024] In the diagram: 1-First agitator; 2-Slurry mixing tank; 3-Collector emulsifier; 4-Foaming agent emulsifier; 5-Flocculant hydrolysis device; 6-Slurry pump; 7-Coal vacuum dewatering machine; 8-Ash vacuum dewatering machine; 9-Ash slurry thickening equipment; 10-Vacuum pump; 11-Third-stage circulating water tank; 12-Coal washing water tank; 13-Ash washing water tank; 14-First and second stage circulating water sedimentation tank; 15-Sealing water tank of ash coal vacuum dewatering machine; 16-Ash coal vacuum pump water tank. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0026] The purpose of this invention is to provide a water and reagent recycling system and method for a fly ash flotation production line, so as to solve the problems existing in the prior art and reduce the cost of wet separation of fly ash.

[0027] The wet separation method mentioned in this manual is flotation.

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] The following is combined Figure 1 The following describes embodiments of the present invention.

[0030] Example 1

[0031] This invention provides a water and reagent recycling system for a fly ash flotation production line, comprising: a three-stage circulating water tank 11, a coal vacuum dewatering machine 7, an ash vacuum dewatering machine 8, a coal washing water tank 12, an ash washing water tank 13, primary and secondary circulating water sedimentation tanks 14, and an ash slurry thickening device 9; the washing water generated by the coal vacuum dewatering machine 7 and the ash vacuum dewatering machine 8 is tertiary circulating water and discharged into the three-stage circulating water tank 11 for later use; the tertiary circulating water stored in the three-stage circulating water tank 11 is reused in the water-using equipment of the flotation process, such as the first agitator 1, and the vacuum generated by the coal vacuum dewatering machine 7. The valve outlet water is discharged to the coal washing water tank 12 for storage and later use. The vacuum valve outlet water generated by the ash vacuum dewatering machine 8 is discharged to the ash washing water tank 13 for storage and later use. The circulating water stored in the coal washing water tank 12 is reused in the coal vacuum dewatering machine 7 as washing water. The circulating water stored in the ash washing water tank 13 is reused in the ash vacuum dewatering machine 8 as washing water. The overflow water of the ash slurry thickening equipment 9 is discharged to the primary and secondary circulating water sedimentation tank 14 for sedimentation treatment. The effluent after sedimentation treatment in the primary and secondary circulating water sedimentation tank 14 is reused in the water purification equipment, which includes the water-using equipment for the flotation process.

[0032] The flushing water produced by the coal vacuum dewatering machine 7 and the ash vacuum dewatering machine 8 in this invention is tertiary circulating water. It contains a relatively high amount of solid particles and needs to be recycled. Specifically, the water in the tertiary circulating water tank 11 is reused in the flotation process equipment (i.e., the first agitator) for further flotation. The vacuum valve outlet water produced by the coal vacuum dewatering machine 7 and the ash vacuum dewatering machine 8 is secondary circulating water. This secondary circulating water can be reused in the coal vacuum dewatering machine 7 and the ash vacuum dewatering machine 8 as flushing water. After sedimentation treatment in the primary and secondary circulating water sedimentation tanks 14, the solid particle content of the water is extremely low, and it can be reused as clean water in water purification equipment with high water requirements. This reduces the input of external clean water and lowers the cost of clean water usage.

[0033] This invention classifies and categorizes circulating water based on the content of solid particles, the proportion of fine particles, and the type of fine particles. Then, according to different levels and types, the circulating water is reused in different water-using equipment, which can reduce the cost of the flotation process.

[0034] Understandably, the fly ash flotation process is a wet separation method. The first agitator 1 is used to agitate the fly ash into a slurry (fly ash plus water), which is usually the first step, hence the name "first agitator." However, some processes have multiple agitators, each agitating the slurry to different concentrations. The water used in these agitators is selected based on the specific circumstances, using different circulating water.

[0035] In some embodiments, the overflow port of the coal flushing water tank 12 is connected to the tertiary circulating water tank 11; the overflow port of the ash flushing water tank 13 is connected to the primary and secondary circulating water sedimentation tanks 14.

[0036] In this embodiment, excess secondary circulating water is discharged to the tertiary circulating water tank 11 and the primary and secondary circulating water sedimentation tanks 14 for further utilization. This increases the flexibility of the system and avoids the entire system from malfunctioning due to the storage capacity limitations of the coal washing water tank 12 and the ash washing water tank 13.

[0037] In some embodiments, the three circulating water pools in this invention are connected in sequence, and the water flow between the circulating water pools is actively controlled according to the different water consumption of each circulating water device, so as to meet the water demand of each device.

[0038] In some embodiments, the solid content in the tertiary circulating water is >5‰; the solid content in the secondary circulating water is 0.5‰-5‰; and the solid content in the primary circulating water is <0.5‰.

[0039] This embodiment provides a specific grading method. In other embodiments, the grading values ​​can be adjusted according to the specific application scenario.

[0040] In some embodiments, the water purification equipment includes one or more of the following: a slurry mixing tank 2, a collector emulsifier 3, a foaming agent emulsifier 4, a flocculant hydrolysis device 5, a slurry pump 6, a sealing water tank 15 for a coal vacuum dewatering machine, and a water tank 16 for a coal vacuum pump. The sealing water tank 15 for a coal vacuum dewatering machine is used to store the sealing water for the coal vacuum dewatering machine 7 and the ash vacuum dewatering machine 8. The vacuum pump 10 used in the coal vacuum dewatering machine 7 and the ash vacuum dewatering machine 8 is a water ring vacuum pump. The water tank 16 for a coal vacuum pump is used to store the water for the water ring vacuum pump.

[0041] In this embodiment, the slurry preparation tank 2 is used for slurry preparation; the collector emulsifier 3 is used for emulsifying the collector; the foaming agent emulsifier 4 is used for emulsifying the foaming agent; the flocculant hydrolysis device 5 is used for hydrolyzing the flocculant; the ash coal vacuum dewatering machine requires sealing water; the vacuum pump 10 of the ash coal vacuum dewatering machine and each slurry pump 6 require shaft seal water; the above water-using components have high water requirements. In traditional systems, external clean water is usually directly supplied to the above-mentioned clean water equipment, while the present invention uses a sedimentation tank to precipitate the primary and secondary ash-containing circulating water to produce clean water with very low solid particle content for reuse, thereby reducing the cost of clean water use.

[0042] In some embodiments, the three-stage circulating water tank 11 is equipped with a stirring device to prevent the settling of fixed particles.

[0043] This embodiment prevents solid particles from settling in the three-stage circulating water tank 11, thus affecting the recovery of solid particles.

[0044] In some embodiments, the primary and secondary circulating water sedimentation tank 14 is a multi-stage sedimentation tank, and the solid content of its effluent is less than 0.05‰.

[0045] This embodiment improves the quality of sedimentation treatment. Specifically, flow-blocking inclined plates are added to the primary and secondary sedimentation tanks, and a filter plate is added at the inlet of the final sedimentation tank. The final effluent solid content of this multi-stage sedimentation process is less than 0.05‰.

[0046] Example 2

[0047] This embodiment provides a method for recycling water and reagents in a fly ash flotation production line, including: identifying the source of circulating water at each point during the fly ash flotation process;

[0048] The circulating water is classified into different grades based on the content of solid particles, the proportion of fine particles, and the type of fine particles.

[0049] Different types of circulating water require different treatments to ensure the rational utilization of each part of the circulating water.

[0050] This invention classifies and categorizes circulating water based on the content of solid particles, the proportion of fine particles, and the type of fine particles. Then, according to different levels and types, the circulating water is reused in different water-using equipment, which can reduce the cost of the flotation process.

[0051] In some embodiments, the circulating water is classified as follows: water with a solid-liquid ratio of <0.5‰ is primary circulating water, water with a solid-liquid ratio of 0.5‰ to 5‰ is secondary circulating water, and water with a solid-liquid ratio of >5‰ is tertiary circulating water.

[0052] This embodiment provides a specific grading method. In other embodiments, the grading values ​​can be adjusted according to the specific application scenario.

[0053] In some embodiments, the tertiary circulating water is reused in the flotation process water equipment to fully recover the solid particles therein. The primary and secondary circulating water are further divided into primary and secondary circulating water with coal particles and primary and secondary circulating water with ash particles according to the different types of fine particles. The primary and secondary circulating water with coal particles is circulated to the coal vacuum dewatering machine 7 as flushing water for reuse. The primary and secondary circulating water with ash particles is circulated to the ash vacuum dewatering machine 8 as flushing water for reuse and discharged to the primary and secondary circulating water sedimentation tank 14 for sedimentation treatment.

[0054] The purified water obtained from sedimentation treatment in the primary and secondary circulating water sedimentation tanks 14 is reused in the water purification equipment.

[0055] See the water and reagent recycling system for the fly ash flotation production line provided in Example 1.

[0056] The embodiments of the present invention possess all the advantages described in Embodiment 1 above, and will not be repeated here.

[0057] Explanation of the principle:

[0058] During the use of circulating water in a flotation production line, fine particles often accumulate. These particles have a large specific surface area and easily adsorb flotation reagents, leading to a decrease in the effective concentration of reagents, weakened hydrophobicity of carbon particles, and reduced collection efficiency. Fine particles interfere with the gas-liquid interface, making the froth layer brittle or overly stable, affecting the transport efficiency of mineralization bubbles. Hydrophilic fine particles cause premature froth breakage, while hydrophobic fine particles carry impurities into the concentrate. Fine particle accumulation significantly increases pulp viscosity, hindering the collision and adhesion efficiency between bubbles and particles, reducing the flotation rate. High viscosity also affects the agitation and aeration effects of the flotation machine, leading to increased energy consumption. Fine particles are easily carried into the froth layer by rising bubbles, even if they are not hydrophobic themselves. This leads to an increase in ash content in the concentrate and a decrease in the grade of carbon products. Fine particles in the circulating water may repeatedly circulate within the flotation column, forming "malignant enrichment," further deteriorating the separation selectivity.

[0059] Frothing agents are crucial reagents in the flotation process. They significantly reduce the surface tension of water, making it easier for air to disperse into microbubbles in the slurry and maintaining foam stability. Some frothers can also enhance particle hydrophobicity, promoting their adhesion to bubbles. Approximately 30%–60% of the frother is fixed to the bubble surface through physical adsorption or chemical action, participating in the formation and stabilization of the foam layer. The frother enters the concentrate product with the foam layer, but most remains in the liquid phase (released back into the slurry after foam collapse). Approximately 5%–15% of the frother adheres to the surface of concentrate particles through mechanical entrainment. In closed-loop circulating water systems, dissolved frothers gradually accumulate. Over time, the frother gradually becomes ineffective or decomposes.

[0060] Based on the above-mentioned mechanisms by which flotation circulating water affects flotation efficiency, and considering the content of solid particles, the proportion of fine particles, and the type of fine particles, the following analysis is made: circulating water containing a large amount of fine coal particles can be recycled; vacuum filtration water and overflow water from ash slurry thickening equipment containing a large amount of fine ash particles need to be treated by sedimentation before they can be reused; and filter cloth rinsing water from vacuum dewatering machine for ash coal with a moderate amount of fine particles can also be directly recycled.

[0061] After classifying and using the circulating water as described above, not only are settling costs reduced, but the circulating water circulation time is also shortened. However, frothers have a limited effective time during flotation; large-volume sedimentation tanks and other water purification devices can cause the reagent in the circulating water to exceed its effective time or separate out of the circulating water. With the circulation time shortened, the residual frother in the circulating water significantly reduces the dosage required for subsequent use, allowing the reagent usage in continuous flotation processes to reach less than 50% of the normal dosage.

[0062] Furthermore, after a month of continuous monitoring of the flotation effect, the flotation effect remained stable using the system and method provided by this invention, without the need for further treatment and monitoring of the circulating water.

[0063] The present invention has the following effects:

[0064] 1. Solve the problem of needing additional water for flotation auxiliary equipment.

[0065] Compared to systems and methods not provided by this invention, each piece of equipment (slurry pump 6, vacuum dewatering machine, etc.) processes one ton of fly ash per ton, reducing water consumption by 1.2 t / h.

[0066] 2. Reduce the amount of reagents used in the flotation process.

[0067] The amount of foaming agent used is reduced by more than 50%.

[0068] 3. Reduce the impact of circulating water carrying away some materials during dehydration, concentration, etc.

[0069] Previously, due to incomplete dehydration and concentration, a large amount of sludge, approximately 2%-5% of the total output, remained in the circulating water tank. This sludge often needed to be cleaned and discharged as waste. With the utilization of circulating water in this invention, the amount of sludge in the circulating water tank is reduced to approximately 1‰.

[0070] 4. Reduce the floor space occupied by the circulating sedimentation tank.

[0071] Compared to previous sedimentation tanks, the water tanks of this invention require only 1 / 3 of the land area of ​​the original sedimentation tanks, and some equipment (such as ash washing water tank 13, coal washing water tank 12, ash coal vacuum dewatering machine sealing water tank 15, and ash coal vacuum pump water tank 16) can be stacked to further utilize space.

[0072] 5. Reduce the frequency of sedimentation tank cleaning.

[0073] The amount of fly ash in the sedimentation tank has been greatly reduced to less than 1 / 10 of the original amount, significantly reducing the frequency of sedimentation tank cleaning.

[0074] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A water and reagent recycling system for use in a fly ash flotation production line, characterized in that: It comprises: a tertiary circulating water pool, a coal vacuum dewatering machine, an ash vacuum dewatering machine, a coal washing water tank, an ash washing water tank, a primary and secondary circulating water sedimentation tank and an ash slurry concentration device; the washing water produced by the coal vacuum dewatering machine and the ash vacuum dewatering machine is tertiary circulating water and is discharged into the tertiary circulating water pool for use, the tertiary circulating water stored in the tertiary circulating water pool is recycled to the water using device of the flotation process to fully recover the solid particles therein, the vacuum valve outlet water produced by the coal vacuum dewatering machine is discharged into the coal washing water tank for storage, the vacuum valve outlet water produced by the ash vacuum dewatering machine is discharged into the ash washing water tank for storage, the circulating water stored in the coal washing water tank is recycled to the coal vacuum dewatering machine as washing water, the circulating water stored in the ash washing water tank is recycled to the ash vacuum dewatering machine as washing water, the overflow water of the ash slurry concentration device is discharged into the primary and secondary circulating water sedimentation tank for sedimentation treatment, and the discharged water after the sedimentation treatment of the primary and secondary circulating water sedimentation tank is used for recycling to the clear water using device; the vacuum valve outlet water produced by the coal vacuum dewatering machine and the ash vacuum dewatering machine is secondary circulating water; the solid content in the tertiary circulating water is > 5 ‰, and the solid content in the secondary circulating water is 0.5 ‰-5 ‰; the overflow port of the coal washing water tank is communicated with the tertiary circulating water pool, the overflow port of the ash washing water tank is communicated with the primary and secondary circulating water sedimentation tank, and the clear water using device comprises a slurry preparation barrel, a collector emulsifier, a foaming agent emulsifier, a flocculant hydrolysis device, a slurry pump, an ash and coal vacuum dewatering machine sealing water tank and an ash and coal vacuum pump water tank.

2. The water and reagent recycling system for use in a fly ash flotation production line according to claim 1, characterized in that: The ash and coal vacuum dewatering machine sealing water tank is used for storing the sealing water of the coal vacuum dewatering machine and the ash vacuum dewatering machine, the vacuum pump used in the coal vacuum dewatering machine and the ash vacuum dewatering machine is a water ring vacuum pump, and the ash and coal vacuum pump water tank is used for storing the water of the water ring vacuum pump.

3. The water and reagent recycling system for use in a fly ash flotation production line according to claim 1, characterized in that: A stirring device is arranged in the tertiary circulating water pool to prevent the sedimentation of solid particles.

4. The water and reagent recycling system for use in a fly ash flotation production line according to claim 1, characterized in that: The primary and secondary circulating water sedimentation tank is a multi-stage sedimentation tank, and the solid content of the outlet water thereof is lower than 0.05 ‰.

5. A method for recycling water and reagents in a fly ash flotation production line, characterized in that: The water and reagent recycling system for a fly ash flotation production line is used to perform the following steps: clearly determining the sources of the circulating water at each position in the fly ash flotation process; classifying the circulating water according to the content of the solid particles, the proportion of fine particles and the types of fine particles; performing different treatments on different circulating water to reasonably utilize each part of the circulating water.

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