Low-quality medium coal upgrading and ash reduction system

Abstract

The utility model provides a low quality medium coal quality upgrading and ash reduction system, including spiral separator, coarse slime separation mechanism, fine slime dewatering mechanism, slime recovery mechanism, spiral separator is used for sorting to low quality medium coal to get spiral separation concentrate and spiral separation tailings, coarse slime separation mechanism is used for screening and centrifugal dewatering to spiral separation tailings and spiral separation concentrate to get under screen water, centrifugal liquid, first high ash medium coal and first low ash medium coal, fine slime dewatering mechanism is used for concentrating, floating and filter pressing treatment to under screen water and centrifugal liquid to get secondary low ash medium coal, one stage thickener overflow and flotation tailings, and slime recovery mechanism is used for concentrating, filter pressing treatment to one stage thickener overflow and flotation tailings to get secondary high ash medium coal, the low quality medium coal quality upgrading and ash reduction system can solve the problems of high ash content of medium coal product and large filter pressing slime water content simultaneously in a set of production system.

Description

Technical Field

[0001] This utility model relates to the field of coal preparation equipment, specifically to a system for upgrading and reducing ash content in low-quality middlings coal. Background Technology

[0002] Coal is typically classified into heavy medium middlings and coarse medium middlings based on its ash content. Heavy medium middlings are of higher quality, with an ash content of approximately 21% and a calorific value of up to 6000 kcal / kg. Coarse medium middlings, on the other hand, are of lower quality, with an ash content of approximately 60% and a calorific value of approximately 2000 kcal / kg. Ash in coal is primarily composed of minerals and is the non-combustible residue after combustion, significantly impacting coal quality and utilization efficiency. High ash content not only reduces the calorific value of coal, increases slagging during combustion, and exacerbates equipment wear, but also increases the ash content of coke in the coking process, thereby affecting blast furnace production efficiency.

[0003] Utility model patent application CN120054756A discloses a coal preparation process and method for activating, upgrading, and reducing ash content in low-quality coal mines. The steps include: crushing and screening high-ash, low-quality anthracite to obtain a crushed product; subjecting the crushed product to two-stage closed-circuit grinding to obtain a ground product; subjecting the ball-milled product to flotation roughing and scavenging to obtain a flotation concentrate; washing the flotation concentrate, followed by heating and activation, and filtration and dewatering to obtain activated clean coal; and subjecting the activated clean coal to flotation fine cleaning to obtain a clean coal product. This coal preparation process and method for activating, upgrading, and reducing ash content in low-ash anthracite products achieves a yield of over 60%, reducing ash content to below 10%, and the closed-circuit middlings recycling design effectively improves resource utilization. All process steps utilize conventional mineral processing equipment, resulting in a simple process, controllable costs, and suitability for large-scale industrial application. However, the steps disclosed in the coal preparation process and method for activating, upgrading and reducing ash content in low-quality coal mines do not simultaneously address the issues of high ash content and low economic benefits in middlings products, as well as the high moisture content in filter press coal slime and the difficulty in selling the products. Summary of the Invention

[0004] In order to solve the problems of high ash content and high moisture content of filter press coal slime in a single production system, the technical solution adopted by this utility model is: a low-quality middling coal upgrading and ash reduction system, including a spiral separator, a coarse coal slime separation mechanism, a fine coal slime dewatering mechanism, and a coal slime recovery mechanism. The spiral separator is used to separate low-quality medium coal to obtain spiral separator concentrate and spiral separator tailings; The coarse coal slime separation mechanism is connected to the rear of the spiral separator and is used to screen and centrifuge the spiral separator tailings to obtain undersize water, centrifugal liquid and primary high-ash middlings; and to screen and centrifuge the spiral separator concentrate to obtain primary low-ash middlings. The fine coal slime dewatering mechanism is connected to the rear of the spiral separator and is used to concentrate, float and filter the screen water and the centrifugal liquid to obtain secondary low-ash middlings, primary thickener overflow and flotation tailings. The coal slime recovery mechanism is connected to the rear of the fine coal slime dewatering mechanism. It is used to concentrate and filter the overflow of the first-stage thickener and the flotation tailings to obtain secondary high-ash middlings.

[0005] Beneficial effects: It can effectively reduce the ash content of coarse and medium coal in deep cone bottom flow, separating it into low-ash and high-ash medium coal, thereby achieving the goal of upgrading and reducing the ash content of low-quality medium coal.

[0006] Based on the above, the coarse coal slime sorting mechanism includes a high-frequency screen, a first centrifuge, a vibrating arc screen, and a second centrifuge. The vibrating arc screen is connected to the rear of the spiral separator and is used to screen the tailings of the spiral separator to obtain undersize water and screened material. The second centrifuge is connected to the rear of the vibrating arc screen and is used to centrifuge the screened material to obtain the centrifuged liquid and the primary high-ash coal. The high-frequency screen is used to screen the spiral separator concentrate. The first centrifuge is connected to the rear of the high-frequency screen and is used to centrifuge the material after screening by the high-frequency screen to obtain the primary low-ash medium coal.

[0007] Based on the above, the fine coal slime dewatering mechanism includes a first-stage thickener, a middlings re-flotation machine, and a plate and frame filter press; The first-stage thickener is used to concentrate the underflow and the centrifuged liquid in one step to obtain a concentrated underflow and the first-stage thickener overflow. The middlings re-flotation machine is used to perform flotation on the first-stage concentrated underflow to obtain flotation concentrate and flotation tailings; The plate and frame filter press is connected to the rear side of the middlings re-selection flotation machine and is used to filter the flotation concentrate to obtain the secondary low-ash middlings.

[0008] Beneficial effects: Through the thickener and middlings re-selection flotation machine in the fine coal slime dewatering mechanism, the underflow and centrifugal liquid can be concentrated and floated, which can improve the recovery rate of secondary low-ash middlings and enable the high-ash coal slime and low-ash coal slime to be fully separated.

[0009] Based on the above, the coal slime recovery mechanism includes a two-stage thickener and a diaphragm filter press; The second-stage thickener is connected to the rear of the middlings re-selection flotation machine and is used to thicken the flotation tailings and the overflow of the first-stage thickener to obtain secondary thickened coal slime. The diaphragm filter press is connected to the rear of the second-stage thickener and is used to filter the secondary thickened coal slime to obtain the secondary high-ash medium coal.

[0010] Beneficial effects: By installing a two-stage thickener and a diaphragm filter press in the coal slime recovery facility, the two-stage thickener can first concentrate the flotation tailings and the overflow from the first-stage thickener, achieving preliminary concentration and dewatering to facilitate subsequent secondary dewatering. Then, the diaphragm filter press performs secondary filtration and dewatering, thereby significantly reducing the moisture content of the secondary high-ash coal and meeting sales requirements.

[0011] Based on the above, the coal slime recycling mechanism also includes a coal slime crusher, which is connected to the rear side of the diaphragm filter press and is used to crush the secondary concentrated coal slime after filtration.

[0012] Beneficial effects: By adding a coal slime crusher, the material after secondary filtration by the diaphragm filter press can be crushed to reduce its particle size and meet the requirements for subsequent sales.

[0013] Based on the above, the two-stage thickener is also connected to a circulating water tank.

[0014] Beneficial effects: By setting up a circulating water tank, the recycling of water resources can be achieved, reducing production costs.

[0015] Based on the above, a spiral concentrate pool is provided between the high-frequency screen and the spiral separator. The spiral concentrate pool is connected to the high-frequency screen through a first pump. The spiral concentrate pool is used to receive the spiral separator concentrate.

[0016] Beneficial effects: By adding a spiral concentrate pool, the spiral concentrate pool can be used to buffer the spiral separation concentrate, which improves the connectivity and adaptability of the processing process and facilitates the screening process of the high-frequency screen.

[0017] Based on the above, a transfer and drainage tank is provided between the second centrifuge and the first-stage thickener. The transfer and drainage tank is connected to the first-stage thickener through a second pump, and the transfer and drainage tank is used to receive the centrifuged liquid.

[0018] Based on the above, coal conveyor belts are respectively installed behind the coarse coal slime sorting mechanism, the fine coal slime dewatering mechanism, and the coal slime recycling mechanism.

[0019] Beneficial effect: By setting up a coal conveyor belt, coal slurry can be transported out continuously in a timely manner.

[0020] This utility model has substantial features and advancements compared to existing technologies. Specifically, it provides a low-quality middlings coal upgrading and ash reduction system. By minimizing engineering work and minimizing production disruption, for coarse and middlings coal, the system utilizes a newly added spiral separator, coarse coal slime separation mechanism, fine coal slime dewatering mechanism, and coal slime recovery mechanism. The spiral separator separates the low-quality middlings coal, yielding spiral separator concentrate and spiral separator tailings. The coarse coal slime separation mechanism then screens and centrifuges the spiral separator tailings and concentrate, yielding underflow, centrifugal liquid, primary high-ash middlings coal, and primary low-ash middlings coal. The fine coal slime dewatering mechanism concentrates, flotates, and filters the underflow and centrifugal liquid, yielding secondary low-ash middlings coal, primary thickener overflow, and flotation tailings. The coal slime recovery mechanism concentrates and filters the primary thickener overflow and flotation tailings, yielding secondary high-ash middlings coal.

[0021] Through the above steps, the ash content of coarse and medium coal in the deep cone bottom flow can be effectively reduced, separating it into low-ash and high-ash medium coal, thereby achieving the goal of upgrading and reducing the ash content of low-quality medium coal.

[0022] Furthermore, by installing a two-stage thickener and a diaphragm filter press in the coal slime recovery facility, the two-stage thickener can first concentrate the flotation tailings and the overflow from the first-stage thickener, achieving preliminary concentration and dewatering to facilitate subsequent secondary dewatering. Then, the diaphragm filter press is used for secondary dewatering, thereby significantly reducing the moisture content of the secondary high-ash coal and meeting sales requirements.

[0023] Therefore, this low-quality middlings coal upgrading and ash reduction system can simultaneously solve the problems of high ash content in middlings coal products and high moisture content in filter press slurry within a single production system. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structural connection relationship of a low-quality medium coal upgrading and ash reduction system provided by this utility model.

[0025] In the diagram: 1. High-frequency screen; 2. First centrifuge; 3. First middlings conveyor belt; 4. Spiral separator; 5. Second-stage thickener; 6. Vibrating arc screen; 7. Second centrifuge; 8. High-ash middlings conveyor belt; 9. Transfer drainage tank; 10. One-end thickener; 11. Middlings re-selection flotation machine; 12. Plate and frame filter press; 13. Third middlings conveyor belt; 14. Fourth middlings conveyor belt; 15. Second middlings conveyor belt; 16. Transfer middlings conveyor belt; 17. Coal slime crusher; 18. Diaphragm filter press. Detailed Implementation

[0026] The technical solution of this utility model will be further described in detail below through specific embodiments.

[0027] Example 1 This embodiment provides a system for upgrading and reducing ash content in low-quality medium-grade coal, such as... Figure 1 As shown, it includes a spiral separator 4, a coarse coal slime separation mechanism, a fine coal slime dewatering mechanism, and a coal slime recovery mechanism. The spiral separator 4 is used to separate low-quality middlings coal to obtain spiral separator concentrate and spiral separator tailings.

[0028] The coarse coal slime separation mechanism is connected to the rear of the spiral separator 4 and is used to screen and centrifuge the spiral separator tailings to obtain undersize water, centrifugal liquid and primary high-ash middlings; and to screen and centrifuge the spiral separator concentrate to obtain primary low-ash middlings.

[0029] The fine coal slime dewatering mechanism is connected to the rear of the spiral separator 4 and is used to concentrate, float and filter the screen water and the centrifugal liquid to obtain secondary low-ash middlings, primary thickener overflow and flotation tailings.

[0030] The coal slime recovery mechanism is connected to the rear of the fine coal slime dewatering mechanism. It is used to concentrate and filter the overflow of the first-stage thickener and the flotation tailings to obtain secondary high-ash middlings.

[0031] Specifically, the coarse coal slime separation mechanism includes a high-frequency screen 1, a first centrifuge 2, a vibrating arc screen 6, and a second centrifuge 7. The vibrating arc screen 6 is connected to the rear of the spiral separator 4 and is used to screen the tailings of the spiral separator to obtain underflow and screened material. The second centrifuge 7 is connected to the rear of the vibrating arc screen 6 and is used to centrifuge the screened material to obtain the centrifuged liquid and the primary high-ash middlings.

[0032] The high-frequency screen 1 is used to screen the spiral separator concentrate. The first centrifuge 2 is connected to the rear of the high-frequency screen 1 and is used to centrifuge the material after screening by the high-frequency screen to obtain the primary low-ash medium coal.

[0033] The fine coal slime dewatering mechanism includes a primary thickener 10, a middlings re-flotation machine 11, and a plate and frame filter press 12. The primary thickener 10 is used to concentrate the underflow and centrifuged liquid to obtain a primary thickened underflow and a primary thickener overflow. The middlings re-flotation machine 11 is used to perform flotation on the primary thickened underflow to obtain flotation concentrate and flotation tailings.

[0034] The plate and frame filter press 12 is connected to the rear side of the middlings re-selection flotation machine and is used to filter the flotation concentrate to obtain the secondary low-ash middlings.

[0035] Specifically, the coal slime recovery mechanism includes a two-stage thickener 5 and a diaphragm filter press 18. The two-stage thickener 5 is connected downstream of the middlings re-selection flotation machine 11 and is used to thicken the flotation tailings and the overflow from the first-stage thickener to obtain secondary thickened coal slime. The diaphragm filter press 18 is connected downstream of the two-stage thickener 5 and is used to filter the secondary thickened coal slime to obtain secondary high-ash middlings.

[0036] Example 2 This embodiment provides a low-quality medium coal upgrading and ash reduction system. The main difference from Embodiment 1 is that in this embodiment, the coal slime recovery mechanism further includes a coal slime crusher 17, which is connected to the rear side of the diaphragm filter press 18 and is used to crush the secondary concentrated coal slime after filter pressing.

[0037] Example 3 This embodiment provides a low-quality medium-grade coal upgrading and ash reduction system. The main difference from Embodiment 1 is that in this embodiment, the two-stage thickener 5 is also connected to a circulating water tank. A spiral concentrate tank is provided between the high-frequency screen 1 and the spiral separator 4. The spiral concentrate tank is connected to the high-frequency screen 1 via a first pump, and is used to receive the spiral separator concentrate. By adding the spiral concentrate tank, the spiral separator concentrate can be buffered, improving the connectivity and adaptability of the processing, and facilitating the high-frequency screen's screening process.

[0038] A transfer drain tank 9 is provided between the second centrifuge 7 and the first-stage thickener 10. The transfer drain tank 9 is connected to the first-stage thickener 10 through a second pump. The transfer drain tank is used to receive the centrifuged liquid.

[0039] Example 4 This embodiment provides a low-quality medium coal upgrading and ash reduction system. The main difference from Embodiment 1 is that in this embodiment, coal conveyor belts are respectively installed behind the coarse coal slime sorting mechanism, the fine coal slime dewatering mechanism, and the coal slime recycling mechanism.

[0040] Specifically, based on their installation location, coal conveyor belts can be divided into the following types as shown in the diagram: First middlings conveyor belt 3, High-ash middlings conveyor belt 8, Third middlings conveyor belt 13, Fourth middlings conveyor belt 14, Second middlings conveyor belt 15, and Transfer middlings conveyor belt 16.

[0041] Actual production verification: Comparison of coal and coal slime products before and after the renovation As shown in Tables 1 and 2, it is evident that the low-quality middlings coal upgrading and ash reduction system provided by this invention can significantly increase the calorific value of low-ash middlings coal. The calorific value formula is: Calorific value ≈ 8200 - 100 × Ad - 10 × Mt (kcal / kg).

[0042] Table 1. Balance Sheet of Coal and Coal Slurry Products Before Modification .

[0043] Table 2 Balance Sheet of Mid-coal and Coal Slurry Products After Modification .

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.

Claims

1. A low-quality middlings upgrading and ash reduction system, characterized in that: This includes a spiral separator, a coarse coal slime separation mechanism, a fine coal slime dewatering mechanism, and a coal slime recovery mechanism; The spiral separator is used to separate low-quality medium coal to obtain spiral separator concentrate and spiral separator tailings; The coarse coal slime separation mechanism is connected to the rear of the spiral separator and is used to screen and centrifuge the spiral separator tailings to obtain undersize water, centrifugal liquid and primary high-ash middlings; and to screen and centrifuge the spiral separator concentrate to obtain primary low-ash middlings. The fine coal slime dewatering mechanism is connected to the rear of the spiral separator and is used to concentrate, float and filter the screen water and the centrifugal liquid to obtain secondary low-ash middlings, primary thickener overflow and flotation tailings. The coal slime recovery mechanism is connected to the rear of the fine coal slime dewatering mechanism. It is used to concentrate and filter the overflow of the first-stage thickener and the flotation tailings to obtain secondary high-ash middlings.

2. The low-quality middlings upgrading and ash reducing system according to claim 1, characterized in that: The coarse coal slime sorting mechanism includes a high-frequency screen, a first centrifuge, a vibrating arc screen, and a second centrifuge. The vibrating arc screen is connected to the rear of the spiral separator and is used to screen the tailings of the spiral separator to obtain undersize water and screened material. The second centrifuge is connected to the rear of the vibrating arc screen and is used to centrifuge the screened material to obtain the centrifuged liquid and the primary high-ash coal. The high-frequency screen is used to screen the spiral separator concentrate. The first centrifuge is connected to the rear of the high-frequency screen and is used to centrifuge the material after screening by the high-frequency screen to obtain the primary low-ash medium coal.

3. The low-quality middlings upgrading and ash reducing system according to claim 2, characterized in that: The fine coal slime dewatering mechanism includes a first-stage thickener, a middlings re-flotation machine, and a plate and frame filter press. The first-stage thickener is used to concentrate the underflow and the centrifuged liquid in one step to obtain a concentrated underflow and the first-stage thickener overflow. The middlings re-flotation machine is used to perform flotation on the first-stage concentrated underflow to obtain flotation concentrate and flotation tailings; The plate and frame filter press is connected to the rear side of the middlings re-selection flotation machine and is used to filter the flotation concentrate to obtain the secondary low-ash middlings.

4. The low-quality middlings upgrading and ash reducing system according to claim 3, characterized in that: The coal slime recovery mechanism includes a two-stage thickener and a diaphragm filter press. The second-stage thickener is connected to the rear of the middlings re-selection flotation machine and is used to thicken the flotation tailings and the overflow of the first-stage thickener to obtain secondary thickened coal slime. The diaphragm filter press is connected to the rear of the second-stage thickener and is used to filter the secondary thickened coal slime to obtain the secondary high-ash medium coal.

5. The low-quality middlings upgrading and ash reducing system according to claim 4, characterized in that: The coal slime recycling mechanism also includes a coal slime crusher, which is connected to the rear side of the diaphragm filter press and is used to crush the secondary concentrated coal slime after filtration.

6. The low-quality middlings upgrading and ash reducing system according to claim 4 or 5, characterized in that: The two-stage thickener is also connected to a circulating water tank.

7. The low-quality middlings upgrading and ash reducing system according to any one of claims 2 to 5, characterized in that: A spiral concentrate pool is provided between the high-frequency screen and the spiral separator. The spiral concentrate pool is connected to the high-frequency screen through a first pump. The spiral concentrate pool is used to receive the spiral separator concentrate.

8. The low-quality middlings upgrading and ash reducing system according to claim 3 or 4 or 5, characterized in that: A transfer tank is provided between the second centrifuge and the first-stage thickener. The transfer tank is connected to the first-stage thickener via a second pump and is used to receive the centrifuged liquid.

9. The low-quality middlings upgrading and ash reducing system according to any one of claims 1-5, characterized in that: Coal conveyor belts are respectively installed behind the coarse coal slime sorting mechanism, the fine coal slime dewatering mechanism, and the coal slime recycling mechanism.

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