CN114653474A

CN114653474A - Coal slime water deep upgrading process

Info

Publication number: CN114653474A
Application number: CN202210480294.7A
Authority: CN
Inventors: 张志刚; 宋有良; 王世臣; 汪才飞; 周建方; 高军
Original assignee: Shandong Boxuan Mineral Resources Technology Development Co ltd
Current assignee: Shandong Boxuan Mineral Resources Technology Development Co ltd
Priority date: 2022-05-05
Filing date: 2022-05-05
Publication date: 2022-06-24
Anticipated expiration: 2042-05-05
Also published as: CN114653474B

Abstract

A process for deeply upgrading slime water belongs to the technical field of deep dewatering of slime. The cyclone mainly plays a role in concentration and classification in the process, is limited by the structure of the cyclone, and cannot efficiently classify the selected coal slime, so that most fine particle (less than 0.2 mm) materials directly enter a concentration and pressure filtration system to be sold as coal slime products, and the economic benefit of coal cannot be fully exerted. And the flotation process has large construction investment in the earlier stage, large occupied space and high investment cost for later maintenance and medicament use. After the coal slime is separated into coarse grains with the grain size of more than 0.3mm and liquid-phase fine grains with the grain size of less than 0.3mm, the liquid-phase fine grains with the grain size of less than 0.3mm are separated into clean coal with the grain size of more than 0.075mm and liquid-phase fine grains with the grain size of less than 0.075mm through a sedimentation centrifuge; the rotating speed of the sedimentation centrifuge 6 is 1600-1800 rpm, and the size of the screen seam is 0.1 mm. The coal slime with the thickness of more than 0.075mm can be obtained, and the coal recovery rate is greatly improved.

Description

Coal slime water deep upgrading process

Technical Field

A process for deeply upgrading slime water belongs to the technical field of deep dewatering of slime.

Background

Coking coal belongs to a scarce coal variety and is an indispensable nonrenewable resource for forming coke and reducing ores. With the improvement of the coal mining mechanization degree and the change of the mining depth, the coal quality condition and the fine fraction content of the coking coal are continuously changed, so that a new process for recovering and dehydrating the coal slime of the coal is urgently needed for improving the utilization rate of the coking coal, particularly for recovering the fine coal slime, so as to improve the recovery rate of the clean coal.

The feeding of fine coal slime separation equipment in the fine coal slime separation process of a coking coal separation plant is mainly overflow of fuzzy classification equipment, namely a swirler, the swirler is mainly used for concentration classification in the process and is limited by the structure of the swirler, and the selected coal slime cannot be efficiently classified, so that most fine particle (less than 0.2 mm) materials directly enter a concentration and pressure filtration system to be sold as coal slime products or are recovered by a flotation process. The coal slime product cannot be sold as the coal slime product, and the economic benefit of the coal cannot be fully exerted.

In the prior art, a flotation process is adopted for recycling, and two parts of slime water, namely clean slime classification cyclone overflow, stacked screen underflow and gangue classification cyclone overflow, are mixed and enter a flotation link together. The coal slime water and the medicament are uniformly mixed by the ore pulp preprocessor and then enter a flotation column for flotation, the flotation clean coal is dehydrated by an air flow-through water squeezing filter press, and the main cleaning clean coal is uniformly mixed by a disc feeder. A mixer is added on the head of the belt conveyor for feeding the clean coal to the bin, so that the clean coal and the flotation clean coal are uniformly mixed. And (5) feeding the flotation tail coal into a thickener. And performing filter pressing on the concentrated bottom flow, and recycling the filtrate of the clean coal and tail coal filter press and the overflow of the thickener. The process has large construction investment in the early stage, large occupied space and high investment cost for later maintenance and medicament use. Based on the background, the main problem to be solved at present is to find a new process or equipment to replace the flotation process.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the process can further separate fine particles in the coal slime, particularly fine particles below 0.2mm, and is low in construction investment, small in occupied area and simple in later maintenance.

The technical scheme adopted by the invention for solving the technical problems is as follows: a coal slime water deep upgrading process is characterized in that: after the coal slime water after the medium is removed from the cleaned coal is selected into coarse grains with the diameter of more than 0.3mm and liquid-phase fine grains with the diameter of less than 0.3mm, the following steps are respectively carried out:

the step a) comprises the following steps: separating the liquid-phase fine particles with the diameter of less than 0.3mm into clean coal with the diameter of more than 0.075mm and liquid-phase fine particles with the diameter of less than 0.075mm by a sedimentation centrifuge; wherein the rotating speed of the sedimentation centrifuge is 1600-1800 rpm, the size of a screen seam is 0.1mm, and the actual intercepted particle size is 0.075 mm;

the step b) comprises the following steps: and separating coarse particles with the diameter of more than 0.3mm into large coarse particles with the diameter of more than 5mm and coal slime with the diameter of 0.3-5 mm, further separating the coarse particles with the diameter of more than 5mm to obtain middlings and middlings, and dehydrating the coal slime with the diameter of 0.3-5 mm to obtain clean coal.

For deep upgrading, a sedimentation centrifuge is introduced, a fine particle outlet of a clean coal cyclone is connected into a system, the sedimentation centrifuge is used for sorting fine particles, namely a dilute phase, which are sorted by the clean coal cyclone once, on one hand, a small amount of coarse particles are inevitably present in the dilute phase at the moment, under the condition that the coarse particles and the fine particles are mixed more complexly at the moment, fine screen gaps are more easily formed in the sedimentation centrifuge, the coarse particles and the fine particles are mutually extruded to form a filter screen under the coordination of the high rotating speed and the mesh aperture of the specific sedimentation centrifuge, the screen gaps are formed among the particles, so that the superfine coal components and water are separated, more and finer high-value coal components are obtained, on the other hand, more coal components can be further recovered from the dilute phase as far as possible, the coal extraction rate is improved, compared with the introduction of a flotation process, the construction investment is smaller, the occupied area is small, only one equipment of the sedimentation centrifuge needs to be maintained at the later stage, the operation cost is low. The coal components and the dilute phase separated by the sedimentation centrifuge respectively pass through a coarse grain outlet and a fine grain outlet to become clean coal or enter a concentration system, and after the dilute phase is concentrated into low-value coal slime by the concentration system, certain product value can be reserved.

In addition, coarse grains with the size of more than 0.3mm obtained from the slime water are further separated by a coarse slime separator, low-density slime is separated to be used as clean coal, a clean coal product is obtained by further dehydration, and middlings are obtained from high-density slime. Through refined separation, the total value of the product can be further improved, and the quality of the clean coal can be improved.

Preferably, the method also comprises a concentration process, and the liquid phase particles with the diameter of less than 0.075mm in the step a) are concentrated into the coal slime product through the concentration process.

The concentration into the coal slime product can further improve the total product value.

Preferably, the coal slime with the diameter of 0.3-5 mm in the step b) is subjected to screen stacking and screening to obtain liquid-phase fine particles with the diameter of less than 0.3mm and coarse particles with the diameter of more than 0.3mm, and the liquid-phase fine particles with the diameter of less than 0.3mm are concentrated into a coal slime product through a concentration process.

In the process of further dehydrating the coal slime with the thickness of 0.3-5 mm, which cannot be completely separated in the process of first separating the coal slime water by 0.3mm, a certain amount of coal particles with the thickness of less than 0.3mm are contained in a liquid phase obtained by the first dehydration, and the part can be concentrated into the coal slime, so that the total product value is improved.

More preferably, the coarse grains with the diameter of more than 0.3mm are dehydrated by a dehydration centrifuge to obtain clean coal.

The solid phase after the screening and sorting is turned into clean coal with the granularity of 0.3-5 mm and low water content, so that a clean coal product can be obtained by completely dehydrating through a dehydrating centrifuge, the liquid phase obtained by the dehydrating centrifuge enters a medium combining barrel in a further optimized mode, the liquid phase can be used for an upstream process after being collected, fine particles circulate in the system, and finally, the fine particles enter overflow in a subsequent link.

Preferably, the concentration process comprises: concentrating by a coal slime thickener, and performing filter pressing by a filter press to obtain a coal slime product.

Preferably, the liquid phase obtained by the overflow of the coal slime thickener is used as circulating clear water, and the underflow can be used as the feeding material of a filter press.

Further preferably, the liquid phase obtained by said filter press is used as recycled clean water.

The liquid phase obtained by filter pressing of the filter press does not contain coal phase basically and can be directly used for upstream processes.

Further preferably, two coal slime concentrators are connected in parallel.

The alternate operation can effectively improve the efficiency of the concentration process and improve the productivity.

Preferably, the large coarse grains with the diameter of more than 5mm obtained in the step b) pass through a medium gangue cyclone to obtain a solid phase, the solid phase sequentially passes through a sieve bend and a high-frequency sieve to obtain medium coal, and the liquid phase of the sieve bend and the high-frequency sieve is medium gangue.

The quality and the granularity are not in inverse proportion, the granularity is fine and is not necessarily high in quality, under the process condition, the coal with the coarse granularity obtained by the high-frequency sieve can only be used as middlings, the liquid phase of the coal can only be used as middlings, the middlings can circularly enter a middlings cyclone to further recover coal components, and the product recovery value can also be improved.

Further preferably, the liquid phase obtained by the medium gangue cyclone enters a concentration process.

The liquid phase obtained by the medium gangue cyclone contains high-quality coal slime particles with fine granularity, so that the total product quality can be further improved by preparing the coal slime through a concentration process.

Preferably, the rotating speed of the sedimentation centrifuge is 1700 rpm.

Under the optimal rotating speed, the process has better matching effect with the coal slime water deep upgrading process, and by utilizing the particle size composition of specific components contained in liquid-phase fine particles with the particle size of less than 0.3mm, finer screen gaps can be formed at 1700rpm, so that more high-quality coal particles can be kept as far as possible, and simultaneously, moisture is removed, and the recovery rate is improved.

Compared with the prior art, the invention has the beneficial effects that: through specific coal slime particle grading, the specific coal slime particle size composition contained in a dilute phase after separation according to the standard of 0.3mm is matched with a sedimentation centrifuge, the coal slime with the grade of 0.075mm can be obtained by dehydration, the coal slime with the size of more than 0.075mm is obtained, and the coal recovery rate is greatly improved; meanwhile, coarse phases above the 0.3mm standard are further sorted by 5mm, and a large amount of coal slime with the granularity of 0.3-5 mm can be further obtained, so that the quality of clean coal of 0.3-5 mm is improved, and the further sorting of the coarse phases above 5mm is that of middlings and middlings, which is equivalent to the improvement of the quality of the middlings and the middlings, so that the overall quality of all products is improved. The investment of the whole process is small, the occupied area is small, and the main maintenance equipment in the later period is only a sedimentation centrifuge, so that the process is suitable for popularization.

Drawings

FIG. 1 is a schematic diagram of a washing system in a slime water deep upgrading system.

FIG. 2 is a schematic diagram of a concentration system in a slime water deep upgrading system.

FIG. 3 is a schematic diagram of a decanter centrifuge.

Wherein, 1, clean coal swirler; 2. a coarse coal slime separator; 3. stacking and screening; 4. a dewatering centrifuge; 5. a medium mixing barrel; 6. a sedimentation centrifuge; 7. a refined coal barrel; 8. a medium gangue swirler; 9. a curved screen; 10. high-frequency screening; 11. a middle gangue barrel; 12. a medium coal bucket; 13. a coal slime thickener; 14. a filter press; 15. a coal slime barrel; 16. a circulating water tank; 17. a clean water tank; 18. a body; 19. a rotor; 20. a material pushing device; 21. a screen basket; 22. and a feeding pipe.

Detailed Description

The present invention is further illustrated by the following examples, example 1 being the best mode of carrying out the invention.

The following test methods for recovery rate were used: and after the system operates for 1 hour, collecting fine coal slime with the thickness of more than 0.075mm, weighing the fine coal slime as M1, respectively measuring the concentration C and the flow L of the fed coal slime water, and calculating the total mass M = C × L of the fed coal slime. Recovery = M1/M8 × 100%.

The following examples and comparative examples are all defined in terms of the size of coal slurry, and unless otherwise specified, "coarse particles having a diameter of 0.3mm or more" means "coarse particles having a diameter of 0.3mm or more".

Example 1

Referring to the attached figures 1-2: the coal slime water deep upgrading system used in the coal slime water deep upgrading process comprises a dehydration system and a concentration system, wherein the dehydration system comprises a clean coal swirler 1, a coarse coal slime separator 2, a stacking sieve 3, a dehydration centrifugal machine 4, a medium combining barrel 5, a sedimentation centrifugal machine 6, a clean coal barrel 7, a medium gangue swirler 8, an arc sieve 9, a high-frequency sieve 10, a medium gangue barrel 11 and a medium coal barrel 12; the bottom of the clean coal swirler 1 is connected with the coarse coal slime separator 2, and the top of the clean coal swirler 1 is connected with the sedimentation centrifuge 6; a fine particle outlet of the coarse coal slime separator 2 is connected with a stacked sieve 3, a coarse particle outlet of the stacked sieve 3 is connected with a dewatering centrifuge 4, a fine particle outlet of the dewatering centrifuge 4 is communicated to a medium combining barrel 5, and coarse particle outlets of the dewatering centrifuge 4 and a sedimentation centrifuge 6 are communicated to a fine coal barrel 7; a coarse grain outlet of the coarse coal slime sorting machine 2 is connected with a medium gangue swirler 8, a coarse grain outlet of the medium gangue swirler 8 is communicated to an arc screen 9, a coarse grain outlet of the arc screen 9 is communicated to a high-frequency screen 10, a coarse grain outlet of the high-frequency screen 10 is communicated to a medium coal bucket 12, and fine grain outlets of the arc screen 9 and the high-frequency screen 10 are communicated to a medium gangue bucket 11. The fine particle outlet of the stacked screen 3, the fine particle outlet of the sedimentation centrifuge 6 and the fine particle outlet of the medium gangue cyclone 8 are communicated to a concentration system.

The concentration system comprises a coal slime thickener 13, a filter press 14, a coal slime barrel 15, a circulating water tank 16 and a clean water tank 17; two coal slime thickeners 13 are arranged in parallel, and one is in a normally closed state and is used as an accident thickener; a coarse grain outlet of the coal slime thickener 13 is communicated with the filter press 14, a coarse grain outlet of the coal slime thickener 13 is communicated with the coal slime barrel 15, a fine grain outlet of the coal slime thickener 13 is communicated with the circulating water tank 16, the circulating water tank 16 is connected with the clean water tank 17, and a fine grain outlet of the filter press 14 is connected with the clean water tank 17.

A process for deeply upgrading coal slime water comprises the steps that after the coal slime water enters a magnetic separator to recover media in a clean coal medium removal screening stage, the tail coal slime water enters a clean coal swirler 1 to be concentrated to obtain coal slime of two parts of overflow and underflow of the swirler, the overflow flows out from a fine particle outlet of the clean coal swirler 1, and the underflow flows out from a coarse particle outlet of the clean coal swirler 1.

Underflow of a clean coal swirler 1, namely coarse particles with the particle size of more than 0.3mm enters a coarse coal slime sorting machine 2 from a coarse particle outlet for sorting, fine particles with the particle size of 0.3-5 mm obtained through sorting of the coarse coal slime sorting machine 2 enter a stacked sieve 3 through a fine particle outlet, the coarse particles with the particle size of more than 0.3mm obtained through sieving of the stacked sieve 3 enter a dewatering centrifuge 4 for dewatering, the coarse particles with the particle size of more than 0.35mm are clean coal and enter a clean coal bucket 7, the fine particles enter a medium combining bucket 5 for circulation in the system, and finally the coarse particles enter overflow in the subsequent link. Wherein, fine particles with the size of less than 0.3mm obtained by the sieve stack 3 enter a concentration system from a fine particle outlet.

The overflow of the clean coal cyclone 1, namely the fine particles with the particle size of less than 0.3mm, enters a sedimentation centrifuge 6 from a fine particle outlet, the coal slurry with the particle size of more than 0.075mm flows out from a coarse particle outlet and enters a clean coal bucket 7 after the sedimentation centrifuge 6 is further separated and dehydrated, and the coal slurry with the particle size of less than 0.075mm enters a concentration system from a fine particle outlet.

Coarse grains with the grain size of more than 5mm obtained from a coarse grain outlet of the coarse slime separator 2 enter a middle gangue cyclone 8, the middle gangue cyclone 8 separates the coarse grains with the grain size of more than 0.3mm and fine grains with the grain size of less than 0.3mm to obtain coarse grains with the grain size of more than 0.3mm, the coarse grains enter a sieve bend 9 through a coarse grain outlet to be dehydrated, the fine grains with the grain size of less than 0.35mm obtained by the sieve bend 9 through dehydration enter a middle gangue barrel 11, the coarse grains with the grain size of more than 0.35mm enter a high-frequency sieve 10 from a coarse grain outlet to be dehydrated, the further obtained fine grains with the grain size of less than 0.35mm enter the middle gangue barrel 11 through a fine grain outlet, and the coarse grains with the grain size of more than 0.35mm enter a middle gangue barrel 12 to obtain the middlings.

Coal slime with the particle size of below 0.3mm obtained from a fine particle outlet of the medium gangue cyclone 8 enters a concentration system.

The coal slurry entering the concentration system enters a coal slurry concentrator 13 for concentration, the coal slurry obtained from the coarse grain outlet is subjected to pressure filtration by a pressure filter 14 to obtain a final coal slurry product, a liquid phase discharged from a fine grain outlet of the coal slurry concentrator 13 sequentially enters a circulating water tank 16 and a clean water tank 17 to be used as circulating water for later use, and the liquid phase obtained from the fine grain outlet of the pressure filter 14 can directly enter the clean water tank 17. Two coal slime thickeners 13 are arranged in parallel and alternately concentrate the coal slime.

Wherein, the coarse slime separator 2 is externally connected with spray water, and the clean water tank 17 is externally connected with supplementary water. The coal slime in the middle gangue barrel 11 can be recycled to enter a middle gangue cyclone 8 for further screening to obtain high-moisture fine coal slime or middling coal.

Referring to FIG. 3: the centrifugal speed of the sedimentation centrifuge 6 is 1700rpm, the screen gap size of the screen basket 21 is 0.1mm, and the actual trapped particle size is 0.075 mm. The sedimentation centrifuge 6 comprises a power system, a machine body 18, a rotor 19, a material pushing device 20, a screen basket 21 and a feeding pipe 22, wherein the rotor 19 is arranged in the machine body 18, one end of the rotor is connected with the power system, and the other end of the rotor is connected with the screen basket 21; the feeding pipe 22 is communicated to the screen basket 21; the pushing device 20 comprises a push rod and a push plate, the push rod is arranged in the center of the rotor 19, one end of the push rod is connected with the bottom of the push plate, the other end of the push rod is connected with a hydraulic device, and the push plate is arranged in the screen basket 21.

The power system directly transmits the power to the screen basket 21 through the rotor 19 without a speed reduction process, so that the rotating speed is greatly improved, the power system is matched with a dilute phase at a fine grain outlet of the clean coal cyclone 1, the requirement on consistency is reduced, and meanwhile, the pushing device 20 is pushed by a hydraulic device, so that solid materials screened in the screen basket 21 can be pushed out. The dilute phase from the fine particle outlet of the clean coal cyclone 1 is guided into the screen basket 21 through the feeding pipe 22, the screen basket 21 rotates at a high speed, coal particles in the dilute phase cover the wall of the screen basket 21 under the action of centrifugal force to form a tiny screen gap, water passes through the screen gap, the coal particles are retained in the screen basket 21, and due to the fact that an overflow part from the clean coal cyclone 1 still contains part of coarse particles and is matched with the fine particles, a fine screen gap can be formed quickly at a high rotating speed, and most of coal components are retained.

In the above steps, the non-illustrated medium coal slime recovery system, concentration and filter pressing, circulating water, water replenishing, detecting, controlling, electrical and other systems are conventional technologies.

By adopting the scheme, a sedimentation centrifuge 6 at 1700rpm is additionally arranged aiming at the fine-grained coal slime difficult to recover, the fine grains obtained by concentration cyclone are directly separated, the coal products with the grain size of more than 0.075mm can be further separated by utilizing the sedimentation centrifuge with the 1700rpm high rotating speed, the separated coarse-grained coal slime can obtain clean coal products, and the water-containing fine grains are subjected to concentration and filter pressing to be used as coal slime products.

And (3) performance test results: and (3) carrying out heavy planting on the fed coal slurry at a concentration C of 107g/L and a flow L of 124M/h, and calculating to obtain the total mass M = C × L =13.268t/h of the fed coal slurry. When the system runs for 1 hour, the recovery rate of collecting fine coal slurry M1 with the thickness of more than 0.075mm is 5.34t, and the recovery rate is = M1/M8 = 100% =5.34 ÷ 13.268 = 100% = 40.25%.

Example 2

A coal slime water deep upgrading process is characterized in that on the basis of an embodiment 1, the rotating speed of a sedimentation centrifuge 6 is set to 1600rpm, and other conditions are the same as those of the embodiment 1.

And (3) performance test results: and (3) carrying out cultivation/h on the fed coal slurry with the concentration C of 102g/L and the flow L of 131M, and calculating to obtain the total mass M = C × L =13.362t/h of the fed coal slurry. When the system runs for 1 hour, the recovery rate of 4.67t of the fine coal slurry M1 with the size of more than 0.075mm is collected, namely, the recovery rate = M1/M8 × 100% =4.67 ÷ 13.362 × 100% = 34.95%.

Example 3

A coal slime water deep upgrading process is characterized in that on the basis of an embodiment 1, the rotating speed of a sedimentation centrifuge 6 is set to be 1800rpm, and other conditions are the same as those of the embodiment 1.

And (3) performance test results: and (3) carrying out cultivation/h on the fed coal slurry with the concentration C of 112g/L and the flow L of 126M, and calculating to obtain the total mass M = C × L =14.112t/h of the fed coal slurry. When the system runs for 1 hour and the collected fine coal slurry M1 with the diameter of more than 0.075mm is 5.01t, the recovery rate = M1/M8 × 100% =5.01 ÷ 14.112 × 100% = 35.50%.

Comparative example 1

A coal slime water deep upgrading process is characterized in that on the basis of an embodiment 1, the rotating speed of a sedimentation centrifuge 6 is set to be 1500rpm, and other conditions are the same as those of the embodiment 1.

And (3) performance test results: and (3) carrying out 134M cultivation/h on the fed coal slurry water at a concentration C of 98g/L and a flow L, and calculating to obtain the total mass M = C = L =13.132t/h of the fed coal slurry. When the system runs for 1 hour, the recovery rate of 3.62t of the fine coal slurry M1 with the size of more than 0.075mm is collected, namely, the recovery rate = M1/M8 × 100% =3.62 ÷ 13.132 × 100% = 27.57%.

Comparative example 2

A coal slime water deep upgrading process is characterized in that on the basis of an embodiment 1, a clean coal cyclone 1 is replaced by a two-stage concentration cyclone, coarse particles with the size of more than 0.2mm and fine particles with the size of less than 0.2mm are finally separated, and other conditions are the same as those of the embodiment 1.

And (3) performance test results: and (3) carrying out harvest/h on the fed coal slurry with the concentration C of 117g/L and the flow L of 123M, and calculating to obtain the total mass M = C × L =14.391t/h of the fed coal slurry. When the system runs for 1 hour, the recovery rate of 4.28t of the fine coal slurry M1 with the size of more than 0.075mm is collected, namely, the recovery rate = M1/M8 × 100% =4.28 ÷ 14.391 × 100% = 29.74%.

Because the coal slime size standard of first step separation is too thin, 6 operation in-process of sedimentation centrifuge, the cooperation effect is not good between the inside different granularity granule of liquid phase fine grain, can not form fine screen gap at 6 inner walls of sedimentation centrifuge, consequently, clean coal recovery effect is not good, simultaneously, the coarse grain more than 0.2mm gets into coarse coal slime sorter 2, fold and sieve 3 after will cause a large amount of fine grain coal particles of 0.2mm ~0.3mm to be taken away along with the dilute phase, lead to clean coal particle further loss, finally lead to the clean coal recovery effect unsatisfactory.

Comparative example 3

A coal slime water deep upgrading process is characterized in that on the basis of an embodiment 1, a clean coal cyclone 1 is replaced by a two-stage concentration cyclone, and finally coarse particles with the size of more than 0.45mm and fine particles with the size of less than 0.45mm are separated, and other conditions are the same as those of the embodiment 1.

And (3) performance test results: and (3) carrying out cultivation/h on the fed coal slurry with the concentration C of 109g/L and the flow L of 115M, and calculating to obtain the total mass M = C × L =12.535t/h of the fed coal slurry. When the system runs for 1 hour, the recovery rate of 3.18t of the fine coal slurry M1 with the size of more than 0.075mm is collected, namely, the recovery rate = M1/M8 × 100% =3.18 ÷ 12.535 × 100% = 25.37%.

The size standard of the coal slime separated in the first step is too coarse, and a large amount of coal components with the particle size of less than 0.45mm enter a sedimentation centrifuge 6, so that formed screen gaps are too large, so that finer particles are lost from the screen gaps, and clean coal is lost; in the coarse coal slime sorter 2 and the large-particle dehydration device of the stack sieve 3, because of the lack of the coal particle supplement screen gaps of 0.3-0.45 mm, part of small-particle coal can be lost, clean coal is further lost, and therefore the recovery efficiency is poor.

Because the size standard of the coal slime separated in the first step is too coarse, in the operation process of the sedimentation centrifuge 6, the matching effect between different particle size particles in liquid phase fine particles is poor, screen gaps formed on the inner wall of the sedimentation centrifuge 6 are too coarse, a large amount of fine coal slime penetrates through the screen gaps to enter dilute phase and finally flows into coal slime products, the recovery yield of clean coal is lost, and the total product value is reduced.

The main advantages of the recovery process are as follows from the examples and comparative examples: different from a flotation process, the method has the advantages of large investment in the early stage, large occupied area, complex process, difficult later maintenance, high cost of materials such as reagents and the like. The process is simple, the investment is small, the occupied area is small, and the later maintenance and the input materials are few. And coarse grain products are further recovered, a specific primary separation standard is utilized, and the specific sedimentation centrifuge 6 condition is matched, so that the coal slime with the particle size of more than 0.075mm is reserved, the recovery rate of coal components is improved, the initial degree of circulating water is improved, and the product value is effectively improved.

The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Claims

1. A coal slime water deep upgrading process is characterized in that: after the coal slime water after the medium is removed from the cleaned coal is selected into coarse grains with the diameter of more than 0.3mm and liquid-phase fine grains with the diameter of less than 0.3mm, the following steps are respectively carried out:

the step a) comprises the following steps: sorting the liquid-phase fine particles with the particle size of less than 0.3mm into clean coal with the particle size of more than 0.075mm and liquid-phase fine particles with the particle size of less than 0.075mm by a sedimentation centrifuge (6); wherein the rotating speed of the sedimentation centrifuge (6) is 1600-1800 rpm, and the size of the screen seam is 0.1 mm;

2. The coal slime water deep upgrading process according to claim 1, characterized in that: the method also comprises a concentration process, wherein in the step a), liquid-phase particles with the particle size of less than 0.075mm are concentrated into a coal slime product through the concentration process.

3. The coal slime water deep upgrading process according to claim 2, characterized in that: and b) separating the coal slime with the diameter of 0.3-5 mm into liquid-phase fine particles with the diameter of less than 0.3mm and coarse particles with the diameter of more than 0.3mm through a stack sieve (3), and concentrating the liquid-phase fine particles with the diameter of less than 0.3mm into a coal slime product through a concentration process.

4. The coal slime water deep upgrading process according to claim 3, characterized in that: and dehydrating the coarse grains with the diameter of more than 0.3mm by a dehydrating centrifuge (4) to obtain the clean coal.

5. The coal slime water deep upgrading process according to claim 2, characterized in that: the concentration process comprises the following steps: the coal slime thickener (13) concentrates and the filter press (14) presses to obtain a coal slime product.

6. The coal slime water deep upgrading process of claim 5, characterized in that: and the liquid phase obtained by the coal slime thickener (13) is used as circulating clear water.

7. The coal slime water deep upgrading process of claim 5, characterized in that: the liquid phase obtained by the filter press (14) is used as clean water.

8. The coal slime water deep upgrading process of claim 6, characterized in that: two coal slime thickeners (13) are arranged in parallel.

9. The coal slime water deep upgrading process of claim 6, characterized in that: and b) passing the large coarse particles with the diameter of more than 5mm through a medium gangue cyclone (8) to obtain a solid phase, sequentially passing the solid phase through an arc screen (9) and a high-frequency screen (10) to obtain medium coal, and taking the liquid phase of the arc screen (9) and the high-frequency screen (10) as medium gangue.

10. The coal slime water deep upgrading process according to claim 1, characterized in that: the rotating speed of the sedimentation centrifuge (6) is 1700 rpm.