A high-clay-content coal gangue valuable component cascade recovery system and process

Abstract

The application discloses a high-clay-content coal gangue valuable component gradient recovery system and process, and belongs to the technical field of coal solid waste resource utilization. The application builds a gradient recovery system composed of a pretreatment unit and a flotation unit, realizes step-by-step efficient recovery of two valuable components, i.e. clean coal and kaolin clay, in the coal gangue through multi-stage crushing, grinding, dissociation, particle size grading and coarse particle pre-enrichment separation, in combination with a switchable preferential floating coal and preferential floating clay double-flotation route, and the tailings after removal of the valuable components can be used as building material raw materials or soil remediation agent raw materials. The application can flexibly switch the production process according to the ash content characteristics of the coal gangue feed, adapt to different quality raw materials, and has the advantages of simple overall process, high equipment integration, embeddability in the existing coal preparation production line, independent processing of gangue mountain solid waste, recyclability of water resources, substantial reduction of processing cost, realization of full-component high-value and harmless utilization of the coal gangue, and high market promotion value.

Description

Technical Field

[0001] This invention relates to the field of coal solid waste resource utilization technology, specifically to a cascade recovery system and process for valuable components of coal gangue with high clay content. Background Technology

[0002] Coal is my country's core energy source at present, and coal washing and processing is a key process to improve coal utilization efficiency and reduce coal combustion pollution. However, the coal washing process generates a large amount of coal gangue solid waste, and traditional treatment methods mainly involve open-air stockpiling, underground backfilling, and rough processing into building materials, which have many technical and environmental drawbacks.

[0003] Among these, open-air stockpiling can easily cause environmental problems such as dust, soil pollution, and groundwater infiltration pollution, and it also occupies a large amount of land resources; underground backfilling is only suitable for coal gangue generated on-site immediately, and cannot handle the solid waste accumulated in existing gangue mountains; conventional building material utilization is constrained by factors such as market supply and demand, transportation radius, and low product added value, resulting in unstable economic benefits and difficulty in large-scale promotion.

[0004] High-clay-content coal gangue contains valuable components not only from residual coal slime but also from clay-based components such as kaolin, giving it dual resource utilization value. However, most existing processing technologies only recover the coal slime component, neglecting the recovery and utilization of kaolin and clay resources, resulting in extremely low utilization rates of valuable components. Furthermore, the lack of targeted grading and sorting processes leads to poor sorting accuracy, high reagent consumption, and high energy consumption due to the mixing of coarse and fine particles, resulting in poor overall resource utilization efficiency.

[0005] In summary, existing technologies suffer from problems such as low resource utilization rate, limited product added value, weak process adaptability, high processing cost, and insufficient environmental protection. There is an urgent need to develop a low-cost, high-efficiency coal gangue treatment process that can recover multiple valuable components in stages, is adaptable to raw materials of different qualities, and is cost-effective. Summary of the Invention

[0006] The present invention aims to solve the above-mentioned technical problems by providing a cascade recovery system and process for valuable components of coal gangue with high clay content.

[0007] To solve the above-mentioned technical problems, the technical solution provided by the present invention is: a cascade recovery system for valuable components of coal gangue with high clay content, including a pretreatment unit and a flotation unit;

[0008] The pretreatment unit is used to dissociate, classify, and sort coal gangue raw materials to produce fine coal slime products and hydrocyclone overflow.

[0009] The flotation unit is used to separate and recover the overflow from the hydrocyclone, producing flotation clean coal, clay products, and tailings. It also produces recyclable sedimentation tank overflow, coal slime plate and frame filter press filtrate, clay plate and frame filter press filtrate, and tailings plate and frame filter press filtrate.

[0010] Preferably, the pretreatment unit includes a jaw crusher, a gyratory crusher, a rod mill, a hydrocyclone, a vibrating arc screen, a spiral separator, and a circulating water tank arranged sequentially along the material flow direction.

[0011] The flotation unit includes a first forced slurry conditioner, a coal slime flotation machine, a coal slime plate and frame filter press, a second forced slurry conditioner, a clay flotation machine, a clay plate and frame filter press, a sedimentation tank, and a tailings plate and frame filter press, arranged in the order of material flow.

[0012] Preferably, the output end of the jaw crusher is connected to the input end of the gyratory crusher, the output end of the gyratory crusher is connected to the input end of the rod mill, the circulating water pool is connected to the input end of the rod mill and provides it with supplementary water, and the output end of the rod mill is connected to the input end of the hydrocyclone.

[0013] The overflow output end of the hydrocyclone is connected to the input ends of the first forced slurry conditioner and the second forced slurry conditioner respectively, and the overflow output end is equipped with a solenoid valve to control all materials to enter the first forced slurry conditioner or the second forced slurry conditioner in one direction.

[0014] The underflow output end of the hydrocyclone is connected to the input end of the vibrating arc screen. The material on the vibrating arc screen is returned to the rod mill, and the material under the screen is connected to the input end of the spiral separator. The tailings of the spiral separator are returned to the rod mill, and the clean coal output end produces clean coal slime product.

[0015] Preferably, the screen aperture of the vibrating arc screen is 2mm, and the grading particle size of the hydrocyclone is 100μm.

[0016] Preferably, the output end of the first forced slurry conditioner is connected to the input end of the coal slime flotation machine, the overflow end of the coal slime flotation machine is connected to the input end of the coal slime plate and frame filter press, and the underflow end of the coal slime flotation machine is equipped with a solenoid valve to control all materials to enter the second forced slurry conditioner or sedimentation tank in one direction; the filtrate of the coal slime plate and frame filter press is returned to the circulating water tank, and the output end of the coal slime plate and frame filter press outputs fine coal slime product.

[0017] Preferably, the output end of the second forced slurry conditioner is connected to the input end of the clay flotation machine, the overflow end of the clay flotation machine is connected to the input end of the clay plate and frame filter press, and the underflow output end of the clay flotation machine is equipped with a solenoid valve to control all materials to enter the sedimentation tank and the first forced slurry conditioner in one direction.

[0018] The filtrate from the clay plate and frame filter press is returned to the circulating water tank, and the clay product is output from the filter solids output end of the clay plate and frame filter press.

[0019] The overflow from the sedimentation tank is returned to the circulating water tank, and the output end of the sedimentation tank is connected to the input end of the tailings plate and frame filter press.

[0020] The filtrate from the tailings plate and frame filter press is returned to the circulating water tank, and the tailings are output from the filter solids output end of the tailings plate and frame filter press.

[0021] This invention also provides a tiered recovery process for valuable components of coal gangue with high clay content, comprising the following steps:

[0022] S1. Valve selection and process route selection: Based on the ash content characteristics of coal gangue feed, select the priority coal floating line or the priority clay floating line by switching the solenoid valves of each piece of equipment.

[0023] S2. Coarse particle pre-enrichment: Through multi-stage crushing, grinding, classification and sorting, the valuable components of coarse particles in coal gangue are recovered, and the fine particles are released for later use.

[0024] S3. Flotation and Classification Recovery: Based on the selected process route, valuable components of fine coal and clay in fine-grained materials are recovered by flotation in stages. The tailings are concentrated and dewatered, and all filtrate water is recycled.

[0025] The selection criteria for the process route in step S1 are as follows: when the overall ash content of the coal gangue raw material is less than 80%, the preferred coal floating line is selected; when the overall ash content of the coal gangue raw material is not less than 80%, the preferred clay floating line is selected.

[0026] In step S1, the valve control method of the priority coal flotation line is as follows: all the overflow material from the hydrocyclone enters the first forced slurry conditioner, all the underflow material from the coal slime flotation machine enters the second forced slurry conditioner, and all the underflow material from the clay flotation machine enters the sedimentation tank.

[0027] The valve control method for the priority floating clay line is as follows: all overflow material from the hydrocyclone enters the second forced slurry conditioner, all underflow material from the coal slime flotation machine enters the sedimentation tank, and all underflow material from the clay flotation machine enters the first forced slurry conditioner.

[0028] Preferably, step S2 specifically includes:

[0029] S201. After being coarsely crushed by a jaw crusher and finely crushed by a gyratory crusher, the coal gangue raw material is fed into a rod mill. The circulating water pool supplies supplementary water to the rod mill to complete the grinding and dissociation of the material.

[0030] S202. The grinding product produced by the rod mill is fed into the hydrocyclone and classified according to the 100μm particle size. The -100μm fine particles are fed into the flotation process with the overflow of the hydrocyclone, and the +100μm coarse particles are fed into the vibrating arc screen with the underflow of the hydrocyclone.

[0031] S203. The vibrating arc screen classifies the particles according to 2mm size. The product on the +2mm screen is returned to the rod mill for secondary grinding, and the product under the -2mm screen is sent to the spiral separator.

[0032] After separation by the spiral separator, low-density coal particles produce clean coal slime, while high-density gangue particles and intergrown tailings are returned to the rod mill for further separation.

[0033] The recovery process for the priority floating coal line in S3 is as follows:

[0034] S301. The overflow material from the hydrocyclone enters the first forced slurry conditioner, and coal slime flotation reagents are added to condition the slurry, preparing coal slime flotation slurry which is then fed into the coal slime flotation machine.

[0035] S302. After flotation by the coal slime flotation machine, the overflow fine coal slurry, i.e. the coal slime flotation overflow, is sent to the coal slime plate and frame filter press for dewatering. The filtered solids are flotation fine coal, and the filtrate from the coal slime plate and frame filter press is returned to the circulating water tank. All the coal slime underflow from the coal slime flotation machine enters the second forced slurry conditioning machine.

[0036] S303, the second forced slurry conditioner adds clay flotation reagents to prepare clay flotation slurry and sends it to the clay flotation machine. The clay flotation overflow is sent to the clay plate and frame filter press for dewatering. The filtered solids are clay products. The filtrate from the clay plate and frame filter press is returned to the circulating water tank.

[0037] S304. The clay flotation tailings of the clay flotation machine are sent to the sedimentation tank for concentration. The overflow of the sedimentation tank is returned to the circulating water tank. The bottom flow of the sedimentation tank is sent to the tailings plate and frame filter press for dewatering. The filtered solids are tailings. The filtrate of the tailings plate and frame filter press is returned to the circulating water tank.

[0038] The recycling process for the preferential floating clay line in step S3 is as follows:

[0039] S301. The overflow material from the hydrocyclone enters the second forced slurry conditioner, where clay flotation reagents are added to condition the slurry and prepare clay flotation slurry, which is then fed into the clay flotation machine.

[0040] S302. After flotation by the clay flotation machine, the clay flotation overflow is sent to the clay plate and frame filter press for dewatering. The filtered solids are clay products. The filtrate from the clay plate and frame filter press is returned to the circulating water tank. The tailings of the clay flotation are all sent to the first forced slurry conditioning machine.

[0041] S303. The first forced slurry conditioner adds coal slime flotation reagents to prepare coal slime flotation slurry, which is then fed into the coal slime flotation machine. The overflow clean coal slurry after flotation, i.e. the coal slime flotation overflow, is sent to the coal slime plate and frame filter press for dewatering. The filtered solids are flotation clean coal, and the filtrate from the coal slime plate and frame filter press is returned to the circulating water tank.

[0042] S304. The tailings of the coal slime flotation machine are sent to the sedimentation tank for concentration. The overflow of the sedimentation tank is returned to the circulating water tank. The bottom flow of the sedimentation tank is sent to the tailings plate and frame filter press for dewatering. The filtered solids are tailings. The filtrate of the tailings plate and frame filter press is returned to the circulating water tank.

[0043] By employing the above methods and systems, the present invention has the following advantages:

[0044] 1. This invention achieves low-cost and high-efficiency recovery of two valuable components in coal gangue: coal component and clay component (mainly kaolin component) through a tiered recovery process of particle size control, coarse-grained spiral separation, and fine-grained flotation.

[0045] 2. Through process design, this invention produces three products: clean coal, clay products, and tailings. The clean coal and clay products have good market benefits, while the tailings can be used as building materials or soil remediation raw materials, thus achieving high-efficiency treatment of coal gangue.

[0046] 3. This invention achieves full dissociation and release of valuable components in coal gangue through multi-stage dissociation using jaw crusher, gyratory crusher and rod mill and grading operation of hydrocyclone before the flotation recovery of valuable components, providing a basic premise for the efficient recovery of valuable components in the future.

[0047] 4. This invention adds a vibrating arc screen and a spiral separator to the underflow of a hydrocyclone. Through the grading and separation operation, the vibrating arc screen provides suitable particle size material of 200μm-2mm for the spiral separator, while the spiral separator realizes the recovery of coarse coal slime in coal gangue. This reduces the power consumption of grinding and dissociation, and also reduces the interference with subsequent flotation operations.

[0048] 5. This invention designs two material output routes at the overflow output end of the hydrocyclone, the tail flow output end of the coal slime flotation, and the tail flow output end of the clay flotation, and selects them by solenoid valves. This realizes two processes: priority flotation of coal slime and priority flotation of clay. The selection can be based on the characteristics of the gangue, mainly the ash content, and has a wider range of applicability.

[0049] 6. The present invention has a simple overall process and requires fewer equipment. It is easy to control and can be embedded as a sub-process in the existing coal preparation process or as a separate process to treat gangue piles. The overall construction cost of the project is controllable and it is highly operable. Attached Figure Description

[0050] Figure 1 This is a system schematic diagram of the present invention.

[0051] Figure 2 This is a schematic diagram of the process flow of the present invention.

[0052] Figure 3 This is a schematic diagram of the structure of the slurry equipment of the present invention.

[0053] As shown in the figure: A. Jaw crusher; B. Gyratory crusher; C. Rod mill; D. Hydrocyclone; E. Vibrating arc screen; F. Spiral separator; G. First forced slurry conditioner; H. Coal slime flotation machine; I. Coal slime plate and frame filter press; J. Second forced slurry conditioner; K. Clay flotation machine; L. Clay plate and frame filter press; M. Sedimentation tank; N. Tailings plate and frame filter press; O. Circulating water tank; G1. Agitator shaft; G2. Air injection pipe; G3. Insulation layer; G4. Exhaust pipe; G5. Ultrasonic probe; G6. Dosing pipe; G7. Feed pipe; G8. Discharge pipe; 1. Coal gangue; 2. Make-up water; 3. Coarse crushing product; 4. Fine crushing product; 5. Grinding product; 6. Hydrocyclone underflow; 7. Hydrocyclone overflow; 8. Oversize product; 9. Undersize product; 10. Tailings; 11. Fine coal slime product; 12. Coal slime flotation reagent; 13. Coal slime flotation slurry; 14. Coal slime flotation overflow; 15. Coal slime flotation underflow; 16. Coal slime plate and frame filter press filtrate; 17. Flotation clean coal; 18. Clay flotation reagent; 19. Clay flotation slurry; 20. Clay flotation tailings; 21. Clay flotation overflow; 22. Clay plate and frame filter press filtrate; 23. Clay product; 24. Sedimentation tank overflow; 25. Sedimentation tank underflow; 26. Tailings; 27. Tailings plate and frame filter press filtrate; 28. Hydrocyclone overflow; 29. ​​Clay flotation tailings; 30. Coal slime flotation tailings. Detailed Implementation

[0054] The present invention will now be described in further detail with reference to the full text.

[0055] Combined with appendix Figures 1-3 A cascade recovery system for valuable components of coal gangue with high clay content is disclosed, including a pretreatment unit and a product flotation unit.

[0056] The pretreatment unit is used to dissociate, classify and sort the gangue raw material to obtain clean coal slime and hydrocyclone overflow 7;

[0057] The flotation unit is used to separate and recover the hydrocyclone overflow 7 to obtain flotation clean coal 17, tailings 26, sedimentation tank overflow 24, coal slime plate and frame filter press filtrate 16, clay plate and frame filter press filtrate 22, and tailings plate and frame filter press filtrate 27.

[0058] In specific implementation of this invention, such as Figure 1 and Figure 2 As shown, the pretreatment unit includes a jaw crusher A, a gyratory crusher B, a rod mill C, a hydrocyclone D, a vibrating arc screen E, a spiral separator F, and a circulating water tank O, arranged in the order of material flow.

[0059] Specifically, the output end of the jaw crusher A is connected to the input end of the gyratory crusher B, the output end of the gyratory crusher B is connected to the input end of the rod mill C, the circulating water tank O is connected to the input end of the rod mill C, the output end of the rod mill C is connected to the input end of the hydrocyclone D, and the overflow output end of the hydrocyclone D is connected to the input ends of the first forced slurry conditioner G and the second forced slurry conditioner J, respectively.

[0060] Specifically, the overflow output end of the hydrocyclone D has a solenoid valve, which forces the overflow output material flow to enter either the first forced slurry conditioner G or the second forced slurry conditioner J.

[0061] In specific implementation of this invention, such as Figure 1 and Figure 2 As shown, the underflow 6 output end of the hydrocyclone is connected to the input end of the vibrating arc screen E, the upper output end of the vibrating arc screen E is connected to the input end of the rod mill C, the lower output end of the vibrating arc screen E is connected to the input end of the spiral separator F, the tailings 10 output end of the spiral separator F is connected to the input end of the rod mill C, and the clean coal output end of the spiral separator F produces clean coal slime product 11;

[0062] Specifically, the vibrating arc screen E has a screen aperture of 2mm, and the hydrocyclone D is set to a grading particle size of 200μm;

[0063] Furthermore, the flotation unit includes a first forced slurry conditioner G, a coal slime flotation machine H, a coal slime plate and frame filter press I, a second forced slurry conditioner J, a clay flotation machine K, a clay plate and frame filter press L, a sedimentation tank M, and a tailings plate and frame filter press N, arranged in the order of material flow.

[0064] Furthermore, the output end of the first forced slurry conditioner G is connected to the input end of the coal slime flotation machine H, the output end of the coal slime flotation overflow 14 is connected to the input end of the coal slime plate and frame filter press I, the output end of the coal slime flotation underflow is connected to the input end of the second forced slurry conditioner J and the input end of the sedimentation tank M respectively, the output end of the filtrate of the coal slime plate and frame filter press I is connected to the input end of the circulating water tank O, and the output end of the filter solids of the coal slime plate and frame filter press I outputs clean coal slime product 11;

[0065] Specifically, the coal slime flotation underflow output end has a solenoid valve, which forces the entire underflow output material to enter the input end of the second forced slurry conditioner J or the sedimentation tank M.

[0066] In specific implementation of this invention, such as Figure 1 and Figure 2As shown, the second forced slurry conditioner J is connected to the input end of the clay flotation machine K. The overflow output end of the clay flotation machine K is connected to the input end of the clay plate and frame filter press L. The underflow output end of the clay flotation machine K is connected to the input end of the sedimentation tank M and the input end of the first forced slurry conditioner G. The filtrate output end of the clay plate and frame filter press L is connected to the input end of the circulating water tank O. The filter solids output end of the clay plate and frame filter press L outputs clay product 23. The overflow output end 24 of the sedimentation tank is connected to the input end of the circulating water tank O. The underflow output end 25 of the sedimentation tank is connected to the input end of the tailings plate and frame filter press N. The filtrate output end of the tailings plate and frame filter press N is connected to the input end of the circulating water tank O. The filter solids output end of the tailings plate and frame filter press N outputs tailings 26.

[0067] Preferably, the clay flotation machine K has a solenoid valve at the underflow output end, so that the underflow output material can only be forced to enter the sedimentation tank M or the input end of the first forced slurry conditioner G.

[0068] In this embodiment, through process design, three products were produced: clean coal, clay product 23, and tailings 26. Both clean coal and clay product 23 have good market benefits, while tailings 26 can be used as building materials or soil remediation raw materials. Overall, this achieves high-efficiency treatment of coal gangue.

[0069] like Figures 2-3 As shown, this invention also discloses a cascade recovery process for valuable components of high-clay-content coal gangue, employing the aforementioned cascade recovery system for valuable components of high-clay-content coal gangue, the steps of which include:

[0070] Step S1: Selecting the solenoid valve;

[0071] Based on the characteristics of the coal gangue 1 to be selected, a priority coal floating line or a priority clay floating line is selected. When the priority coal and clay floating line is selected, the overflow output of the hydrocyclone 7 selects all the material to enter the first forced slurry adjuster G, the bottom flow output of the coal slime flotation selects all the material to enter the input of the second forced slurry adjuster J, and the bottom flow output of the clay flotation machine K selects all the material to enter the sedimentation tank M.

[0072] When prioritizing the floating of clay, the overflow output of the hydrocyclone 7 selects all the material to enter the second forced slurry conditioner J, the bottom flow output of the coal slime flotation selects all the material to enter the input of the sedimentation tank M, and the bottom flow output of the clay flotation machine K selects all the material to enter the input of the first forced slurry conditioner G.

[0073] Preferably, the flotation route is selected based on the ash content of the coal gangue 1 feed. When the overall ash content of the raw material is less than 80%, the coal-preferred flotation route is selected; otherwise, the clay-preferred flotation route is selected.

[0074] Step S2: Coarse-grain pre-enrichment;

[0075] Jaw crusher A is used for coarse crushing of coal gangue 1. Gyratory crusher B performs fine crushing on the coarse product 3 produced by jaw crusher A. Rod mill C performs grinding and dissociation on the fine product 4 produced by gyratory crusher B. Circulating water tank O adds makeup water 2 to rod mill C. Hydrocyclone D is used for classifying the grinding product 5 of rod mill C, with a classification particle size of 100μm, including coarse material +100μm.

[0076] After classification, the fine particles (-100μm) that are fully dissociated enter the flotation recovery step with the overflow 7 of the hydrocyclone. The coarse particles (+100μm) are fed into the vibrating arc screen E with the underflow 6 of the hydrocyclone. The vibrating arc screen E classifies the coarse particles in the underflow 6 of the hydrocyclone to a particle size of 2mm. The coarse particles (+2mm) that are screened over are fed back into the rod mill C, while the undersize particles (9-2mm) are fed into the spiral separator F for separation. Low-density coal particles are discharged inside the spiral separator F to become clean coal slime product 11, while the high-density gangue particles are fed back into the rod mill C with the tailings 10 for dissociation.

[0077] In this embodiment, before the flotation recovery of valuable components, the valuable components in coal gangue 1 are fully dissociated and released through multi-stage dissociation by jaw crusher A, gyratory crusher B and rod mill C and grading operation by hydrocyclone D, which provides a basic premise for the efficient recovery of valuable components in the future.

[0078] In this embodiment, by adding a vibrating arc screen E and a spiral separator F to the underflow 6 of the hydrocyclone, the vibrating arc screen E provides suitable particle size material of 200μm-2mm for the spiral separator through the grading-separation operation, while the spiral separator realizes the recovery of coarse coal slime in the coal gangue 1, which reduces the power consumption of grinding and dissociation, and also reduces the interference to subsequent flotation operations.

[0079] Step S3: Flotation recovery.

[0080] When selecting the preferred coal floating line;

[0081] The first forced slurry conditioner G performs slurry conditioning on the overflow 7 of the hydrocyclone, and adds coal slime flotation reagent 12 during the conditioning process. The resulting coal slime flotation slurry 13 enters the coal slime flotation machine H for flotation. The clean coal is discharged with the coal slime flotation overflow 14 and enters the coal slime plate and frame filter press I for dewatering. The resulting filter solids are the flotation clean coal 17, while the filtrate 16 from the coal slime plate and frame filter press re-enters the circulating water tank O. The gangue is fed with the coal slime flotation underflow 15 into the second forced slurry conditioner J for slurry conditioning, where clay flotation reagent 18 is added, and clay flotation slurry 19 is produced. After slurry preparation, the clay flotation slurry 19 enters the clay flotation machine K for flotation. The clay, mainly kaolin, enters the clay plate and frame filter press L with the clay flotation overflow 21 for dewatering. The filter solids are clay product 23, and the filtrate 22 from the clay plate and frame filter press enters the circulating water tank O. Other components enter the sedimentation tank M with the clay flotation tailings 20 for concentration. The sedimentation tank overflow 24 enters the circulating water tank O, and the sedimentation tank underflow 25 enters the tailings plate and frame filter press N for dewatering. The filter solids are tailings 26, and the tailings plate and frame filter press filtrate 27 enters the circulating water tank O.

[0082] When selecting the preferred clay coal line;

[0083] The second forced slurry conditioner J performs slurry conditioning on the overflow '28 of the hydrocyclone, and adds clay flotation reagent 18 during the conditioning process. After conditioning, the resulting clay flotation slurry 19 enters the clay flotation machine K for flotation. The clay is discharged with the clay flotation overflow 21 and enters the clay plate and frame filter press L for dewatering. The resulting filter solid is the clay product 23, while the filtrate 22 from the clay plate and frame filter press re-enters the circulating water tank O. Gangue and coal slime enter the first forced slurry conditioner G with the clay flotation tail '29 for slurry conditioning, and coal slime flotation reagent 12 is added. After conditioning, the coal slime flotation slurry 13 enters the coal slime flotation machine H for flotation. The coal particles, along with the coal slime flotation overflow 14, enter the coal slime plate and frame filter press I for dewatering. The filtered solids are flotation clean coal 17, and the filtrate 16 from the coal slime plate and frame filter press enters the circulating water tank O. Other components, along with the coal slime flotation tailings '30, enter the sedimentation tank M for concentration. The sedimentation tank overflow 24 enters the circulating water tank O, and the sedimentation tank underflow 25 enters the tailings plate and frame filter press N for dewatering. The filtered solids are tailings 26, and the tailings plate and frame filter press filtrate 27 enters the circulating water tank O.

[0084] In this embodiment, a tiered recovery process consisting of particle size control, coarse spiral separation, and fine flotation is used to achieve low-cost and high-efficiency recovery of two valuable components in coal gangue: coal components and clay, mainly kaolin components.

[0085] In this embodiment, two material output routes are designed at the overflow output end of the hydrocyclone, the output end of the coal slime flotation underflow 15, and the output end of the clay flotation tailflow 20, and selected by solenoid valves. This realizes two processes: priority flotation of coal slime and priority flotation of clay. The selection can be made according to the characteristics of the gangue, which is mainly ash content, and has a wider range of applicability.

[0086] In this embodiment, the overall process is simple and requires fewer pieces of equipment, making it easy to control. It can be embedded as a sub-process in the existing coal preparation process or used as a separate process to treat gangue piles. The overall construction cost of the project is controllable and highly operable.

[0087] Example 1: Cascade Recovery System for Valuable Components of High-Clay-Content Coal Gangue

[0088] like Figure 1 As shown, this embodiment provides a cascade recovery system for valuable components of coal gangue with high clay content, including two core modules: a pretreatment unit and a flotation unit. The equipment is connected in an orderly manner according to the material flow direction to form a closed-loop circular production system.

[0089] The core equipment of the pretreatment unit includes a jaw crusher (A), a gyratory crusher (B), a rod mill (C), a hydrocyclone (D), a vibrating arc screen with a 2mm aperture (E), a spiral separator (F), and a circulating water tank (O). After two stages of crushing and rod mill separation, the material is fed into the hydrocyclone (D) for 100μm particle size classification. Fine overflow material (hydrocyclone overflow 7) enters the flotation unit, while coarse underflow material (hydrocyclone underflow 6) undergoes secondary classification via the vibrating arc screen (E). The +2mm overflow product (8) is returned to the rod mill (C) for further grinding, while the -2mm underflow product (9) is processed by the spiral separator (F) to recover coarse coal slime product (11). The tailings (10) are then returned for further separation, maximizing raw material utilization.

[0090] The core equipment of the flotation unit includes a first forced slurry conditioner G, a coal slime flotation machine H, a coal slime plate and frame filter press I, a second forced slurry conditioner J, a clay flotation machine K, a clay plate and frame filter press L, a sedimentation tank M, a tailings plate and frame filter press N, and supporting pipeline solenoid valves. The unidirectional flow of materials is controlled by three core solenoid valves, allowing switching between two flotation process routes to adapt to different ash content raw materials. All filtrate and sedimentation tank overflow 24 generated from all processes are recycled to the circulating water tank O, achieving water resource recycling.

[0091] Example 2: Preferred floating coal line process, raw material ash content <80%.

[0092] For high-clay coal gangue with an ash content of less than 80% and a high coal component content, a priority coal flotation process is adopted, and the specific steps are as follows:

[0093] S1. Process Selection: Through the control of solenoid valves, the overflow of hydrocyclone 7 is all directed into the first forced slurry conditioner G, the underflow of coal slime flotation machine H is all directed into the second forced slurry conditioner J, and the underflow of clay flotation machine K is all directed into the sedimentation tank M, thus locking in the preferred coal flotation route.

[0094] S2. Coarse pre-enrichment: Coal gangue 1 is coarsely crushed by jaw crusher A and finely crushed by gyratory crusher B, and then fed into rod mill C. Circulating water tank O replenishes production water 2 to complete the full separation of materials. Grinding product 5 is classified by hydrocyclone D at 100μm. Fine overflow (hydrocyclone overflow 7) enters the flotation process, while coarse underflow (hydrocyclone underflow 6) is classified by 2mm vibrating arc screen E. Oversize product 8 is returned to rod mill C for secondary grinding, and undersize product 9 is separated by spiral separator F to produce coarse fine coal slime product 11. Tailings 10 are returned for separation.

[0095] S3. Flotation Recovery: The first forced slurry conditioner G adds coal slime flotation reagent 12 to the fine overflow material to prepare a uniform coal slime flotation slurry 13, which is then sent to the coal slime flotation machine H. The overflow clean coal slurry after flotation, i.e., the coal slime flotation overflow 14, is dewatered by the coal slime plate and frame filter press I to obtain a high-purity flotation clean coal product 17. The filtrate 16 from the coal slime plate and frame filter press is recycled. The tailings 15 from the coal slime flotation underflow are sent to the second forced slurry conditioner J, where clay flotation reagent 18 is added to adjust the slurry before it is sent to the clay flotation machine K. The clay flotation overflow 21 is dewatered by the clay plate and frame filter press L to obtain a kaolin clay product 23. The tailings 20 from the clay flotation tailings are sent to the sedimentation tank M for concentration. The sedimentation tank underflow 25 is dewatered by the tailings plate and frame filter press N to obtain a tailings product 26. The sedimentation tank overflow 24 and the tailings plate and frame filter press filtrate 27 are all returned to the circulating water tank O.

[0096] Example 3: Preferred floating clay line process, raw material ash content ≥80%.

[0097] For high-clay coal gangue with an ash content of not less than 80% and a high clay content, a clay-preferential floating process route is adopted, and the specific steps are as follows:

[0098] S1. Process Selection: Through the control of solenoid valves, the overflow of hydrocyclone 7 is all directed into the second forced slurry conditioner J, the underflow of coal slime flotation machine H is all directed into sedimentation tank M, and the underflow of clay flotation machine K is all directed into the first forced slurry conditioner G, thus locking in the priority floating clay route.

[0099] S2. Coarse pre-enrichment: The pretreatment process is exactly the same as in Example 2, completing multi-stage crushing, grinding, classification, and coarse coal slime recovery operations to prepare flotation fine particles.

[0100] S3, Flotation Recovery: The second forced slurry conditioner J adds clay flotation reagent 18 to the fine-particle overflow material, i.e., the hydrocyclone overflow 28, to prepare clay flotation slurry 19, which is then sent to the clay flotation machine K; the clay flotation overflow 21 is dewatered by the clay plate and frame filter press L to obtain kaolin clay product 23, and the filtrate 22 from the clay plate and frame filter press is recycled; the tailings '29 of the clay flotation are sent to the first forced slurry conditioner G, where coal slime flotation reagent 12 is added to adjust the slurry before it is sent to the coal slime flotation machine H; the coal slime flotation overflow 14 is dewatered by the coal slime plate and frame filter press I to obtain flotation clean coal product 17, and the tailings '30 of the coal slime are sent to the sedimentation tank M for concentration; the bottom flow 25 of the sedimentation tank is dewatered by the tailings plate and frame filter press N to obtain tailings product 26, and the sedimentation tank overflow 24 and all filtrates are returned to the circulating water tank O, achieving a closed-loop water resource recycling throughout the entire process.

[0101] Example 4: Equipment Adaptation and Cyclic Control.

[0102] The forced slurry conditioning equipment G and J used in this invention are equipped with a housing. Inside the housing, there is a stirring shaft G1 driven by a motor, and an ultrasonic probe G5 and a heat insulation layer G3 are installed inside. The outer side of the housing is connected to an air injection pipe G2, an exhaust pipe G4, a chemical dosing pipe G6, a feed pipe G7, and a discharge pipe G8, which facilitates the operation of the equipment such as feeding, chemical dosing, exhaust, and air injection.

[0103] It can achieve precise mixing of reagents and uniform modulation of slurry, thereby improving the flotation reaction efficiency; all solenoid valves adopt one-button switching control, making process switching convenient and highly automated; the water circulation system has no wastewater discharge and the recycling rate can reach more than 95%, which greatly reduces production and operating costs.

[0104] The present invention and its embodiments have been described above. This description is not restrictive, and the embodiments shown throughout are only one of the embodiments of the present invention. The actual structure is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A cascade recovery system for valuable components of high-clay-content coal gangue, characterized in that, Includes a pretreatment unit and a flotation unit; The pretreatment unit is used to dissociate, classify and sort the coal gangue (1) raw material to produce fine coal slime product (11) and hydrocyclone overflow (7). The flotation unit is used to sort and recover the hydrocyclone overflow (7) to produce flotation clean coal (17), clay products (23), and tailings (26), while also producing recyclable sedimentation tank overflow (24), coal slime plate and frame filter press filtrate (16), clay plate and frame filter press filtrate (22), and tailings plate and frame filter press filtrate (27).

2. The cascade recovery system for valuable components of high-clay-content coal gangue according to claim 1, characterized in that: The pretreatment unit includes a jaw crusher (A), a gyratory crusher (B), a rod mill (C), a hydrocyclone (D), a vibrating arc screen (E), a spiral separator (F), and a circulating water tank (O), arranged sequentially along the material flow direction. The flotation unit includes a first forced slurry conditioner (G), a coal slime flotation machine (H), a coal slime plate and frame filter press (I), a second forced slurry conditioner (J), a clay flotation machine (K), a clay plate and frame filter press (L), a sedimentation tank (M), and a tailings plate and frame filter press (N), arranged in the order of material flow.

3. The cascade recovery system for valuable components of high-clay-content coal gangue according to claim 2, characterized in that: The output end of the jaw crusher (A) is connected to the input end of the gyratory crusher (B), the output end of the gyratory crusher (B) is connected to the input end of the rod mill (C), the circulating water tank (O) is connected to the input end of the rod mill (C) and provides it with supplementary water, and the output end of the rod mill (C) is connected to the input end of the hydrocyclone (D). The overflow output end of the hydrocyclone (D) is connected to the input ends of the first forced slurry conditioner (G) and the second forced slurry conditioner (J), respectively, and the overflow output end is equipped with a solenoid valve to control all materials to enter the first forced slurry conditioner (G) or the second forced slurry conditioner (J) in one direction. The underflow output end of the hydrocyclone (D) is connected to the input end of the vibrating arc screen (E). The material on the vibrating arc screen (E) is returned to the rod mill (C), and the material under the screen is connected to the input end of the spiral separator (F). The tailings of the spiral separator (F) are returned to the rod mill (C), and the clean coal output end produces clean coal slime product (11).

4. The cascade recovery system for valuable components of high-clay-content coal gangue according to claim 3, characterized in that: The vibrating arc screen (E) has a screen aperture of 2 mm, and the hydrocyclone (D) has a grading particle size of 100 μm.

5. The cascade recovery system for valuable components of high-clay-content coal gangue according to claim 3, characterized in that: The output end of the first forced slurry conditioner (G) is connected to the input end of the coal slime flotation machine (H). The overflow end of the coal slime flotation machine (H) is connected to the input end of the coal slime plate and frame filter press (I). The underflow end of the coal slime flotation machine (H) is equipped with a solenoid valve to control all materials to enter the second forced slurry conditioner (J) or sedimentation tank (M) in one direction. The filtrate of the coal slime plate and frame filter press (I) is returned to the circulating water tank (O). The output end of the coal slime plate and frame filter press (I) outputs fine coal slime product (17).

6. The cascade recovery system for valuable components of high-clay-content coal gangue according to claim 3, characterized in that: The output end of the second forced slurry conditioner (J) is connected to the input end of the clay flotation machine (K). The overflow end of the clay flotation machine (K) is connected to the input end of the clay plate and frame filter press (L). The underflow output end of the clay flotation machine (K) is equipped with a solenoid valve to control all materials to enter the sedimentation tank (M) and the first forced slurry conditioner (G) in one direction. The filtrate from the clay plate and frame filter press (L) is returned to the circulating water tank (O), and the clay product (23) is output from the filter solids output end of the clay plate and frame filter press (L). The overflow of the sedimentation tank (M) is returned to the circulating water tank (O), and the output end of the sedimentation tank (M) is connected to the input end of the tailings plate and frame filter press (N); The filtrate from the tailings plate and frame filter press (N) is returned to the circulating water tank (O), and the tailings plate and frame filter press (N) outputs tailings (26) from the filter solids output end.

7. A cascade recovery process for valuable components of high-clay-content coal gangue, characterized in that: Includes the following steps: S1. Valve selection and process route selection: Based on the ash content characteristics of coal gangue feed, select the priority coal floating line or the priority clay floating line by switching the solenoid valves of each piece of equipment. S2. Coarse particle pre-enrichment: Through multi-stage crushing, grinding, classification and sorting, the valuable components of coarse particles in coal gangue are recovered, and the fine particles are released for later use. S3. Flotation and Classification Recovery: Based on the selected process route, valuable components of fine coal and clay in fine-grained materials are recovered by flotation in stages. The tailings are concentrated and dewatered, and all filtrate water is recycled.

8. The cascade recovery process for valuable components of high-clay-content coal gangue according to claim 7, characterized in that: The selection criteria for the process route in step S1 are as follows: when the overall ash content of the coal gangue raw material is less than 80%, the preferred coal floating line is selected; when the overall ash content of the coal gangue raw material is not less than 80%, the preferred clay floating line is selected.

9. The cascade recovery process for valuable components of high-clay-content coal gangue according to claim 7, characterized in that: In step S1, the valve control method of the priority coal flotation line is as follows: the overflow material of the hydrocyclone (7) enters the first forced slurry conditioner (G), the underflow material of the coal slime flotation machine (H) enters the second forced slurry conditioner (J), and the underflow material of the clay flotation machine (K) enters the sedimentation tank (M). The valve control method for the priority floating clay line is as follows: the overflow material of the hydrocyclone (7) all enters the second forced slurry conditioner (J), the underflow material of the coal slime flotation machine (H) all enters the sedimentation tank (M), and the underflow material of the clay flotation machine (K) all enters the first forced slurry conditioner (G).

10. The cascade recovery process for valuable components of high-clay-content coal gangue according to claim 9, characterized in that: Step S2 specifically includes: S201. Coal gangue (1) raw material is coarsely crushed by jaw crusher (A) and finely crushed by gyratory crusher (B), and then fed into rod mill (C). The circulating water pool (O) supplies supplementary water (2) to rod mill (C) to complete the grinding and dissociation of materials. S202. The grinding product (5) produced by the rod mill (C) is fed into the hydrocyclone (D) and classified according to the 100μm particle size. The -100μm fine particles are fed into the flotation process with the overflow (7) of the hydrocyclone, and the +100μm coarse particles are fed into the vibrating arc screen (E) with the underflow (6) of the hydrocyclone. S203. The vibrating arc screen (E) is classified according to the particle size of 2mm. The product (8) on the +2mm screen is returned to the rod mill (C) for secondary grinding, and the product (9) under the -2mm screen is sent to the spiral separator (F). S204. After separation by the spiral separator (F), the low-density coal particles produce clean coal slime product (11), while the high-density gangue particles and intergrown tailings (10) are returned to the rod mill (C) for further separation. The recovery process for the priority floating coal line in S3 is as follows: S301, the overflow (7) material from the hydrocyclone enters the first forced slurry conditioner (G), coal slime flotation reagent (12) is added to condition the slurry, coal slime flotation slurry (13) is prepared and sent to the coal slime flotation machine (H); S302. After flotation by the coal slime flotation machine (H), the overflow fine coal slurry, i.e., the coal slime flotation overflow (14), is sent to the coal slime plate and frame filter press (I) for dewatering. The filtered solids are flotation fine coal (17), and the filtrate (16) of the coal slime plate and frame filter press is returned to the circulating water tank (O). All the coal slime flotation underflow (15) of the coal slime flotation machine (H) enters the second forced slurry conditioning machine (J). S303, the second forced slurry conditioner (J) adds clay flotation reagent (18) to condition the slurry, prepares clay flotation slurry (19) and sends it to the clay flotation machine (K), the clay flotation overflow (21) is sent to the clay plate and frame filter press (L) for dewatering, the filtered solid is clay product (23), and the filtrate (22) of the clay plate and frame filter press is returned to the circulating water tank (O); S304, the clay flotation tailings (20) of the clay flotation machine (K) are sent to the sedimentation tank (M) for concentration, the overflow (24) of the sedimentation tank is returned to the circulating water tank (O), the bottom flow (25) of the sedimentation tank is sent to the tailings plate and frame filter press (N) for dewatering, the filtered solids are tailings (26), and the filtrate (27) of the tailings plate and frame filter press is returned to the circulating water tank (O). The recycling process for the preferential floating clay line in step S3 is as follows: S301, the overflow (28) material from the hydrocyclone enters the second forced slurry conditioner (J), and clay flotation reagent (18) is added to condition the slurry, and clay flotation slurry (19) is prepared and sent to the clay flotation machine (K). S302, After the clay flotation machine (K) floats, the clay flotation overflow (21) is sent to the clay plate and frame filter press (L) for dewatering, and the filtered solids are clay products (23). The filtrate (22) of the clay plate and frame filter press is returned to the circulating water tank (O); the clay flotation tailings (29) all enter the first forced slurry conditioning machine (G). S303, The first forced slurry conditioner (G) adds coal slime flotation reagent (12) to condition the slurry, prepares coal slime flotation slurry (13), and sends it to the coal slime flotation machine (H). The overflow clean coal slurry after flotation, namely the coal slime flotation overflow (14), is sent to the coal slime plate and frame filter press (I) for dewatering. The filtered solid is flotation clean coal (17), and the filtrate (16) of the coal slime plate and frame filter press is returned to the circulating water tank (O). S304, The tailings of the coal slime flotation machine (H) (30) are sent to the sedimentation tank (M) for concentration. The overflow (24) of the sedimentation tank is returned to the circulating water tank (O). The bottom flow (25) of the sedimentation tank is sent to the tailings plate and frame filter press (N) for dewatering. The filtered solids are tailings (26). The filtrate (27) of the tailings plate and frame filter press is returned to the circulating water tank (O).

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