CN103386355B - A kind of high pressure roller selective molecular attraction of middle coal and method for separating - Google Patents

Abstract

The invention discloses a high-pressure roller selective crushing and sorting method for middling coal, which belongs to the technical field of mineral processing. Follow the steps below: ① crush the raw coal below the upper limit of particle size suitable for the subsequent coal preparation equipment, and deslim the raw coal after desliming into the gravity separation equipment to obtain clean coal I, medium coal I and gangue I; Medium coal Ⅰ is crushed below the upper limit of the crushing particle size suitable for high-pressure roller mills, and ultra-fine crushed by high-pressure roller mills. The ultra-fine crushed products are deslimed, and the deslimed products enter gravity separation equipment to obtain clean coal Ⅱ and medium coal Ⅱ, gangue Ⅱ, and medium coal Ⅱ return to the high-pressure roller mill and merge with medium coal Ⅰ for crushing and separation; ③Coal slime water is flotation after concentration and slurry adjustment to obtain flotation clean coal and flotation tailings . Compared with the traditional medium coal crushing process, the method of the present invention has high product dissociation degree, good follow-up gravity separation effect, can increase the yield of clean coal, fully and reasonably recover and utilize coal resources, and reduce waste of resources.

Description

A high-pressure roller selective crushing and sorting method for medium coal

technical field

The invention relates to a processing technology for washing middling coal, in particular to a high-pressure roller selective crushing and sorting method for middling coal.

Background technique

Coal is the energy resource with the widest distribution and the largest reserves in China, and occupies an extremely important position in my country's national economic and social development. Although my country has abundant coal resources, the distribution of coal types and quantities is extremely unbalanced, and major coking coals such as fat coal, coking coal, and lean coal are scarce. According to statistics, in addition to lignite accounting for 12.7% of the proven reserves, in hard coal, low metamorphic bituminous coal accounted for 42.4% of the total, and lean coal and anthracite accounted for 17.3%. The amount of medium-metamorphic bituminous coal is small, accounting for only 27.6%, and most of them are gas coal, accounting for 46.9% of medium-metamorphic bituminous coal. Fatty coal, coking coal, and lean coal are less, accounting for 13.6%, 24.3%, and 15.1% of the medium-metamorphic bituminous coal. At present, almost all medium coal in my country's main coking coal preparation plants is used as fuel, which is undoubtedly a great waste of scarce coal in our country.

Similarly, steam coal also contains a large amount of gangue coal, and a large amount of medium coal will also be produced after washing. When medium coal is directly used as fuel, it is unfavorable to the operation of the boiler. In addition to the reduction of boiler efficiency, there are also phenomena such as a significant drop in temperature, unstable combustion, and deterioration of liquid slag discharge, which significantly reduces the reliability and economy of boiler operation. , Increase the burning of heavy oil, thereby reducing the efficiency of power generation, increasing the cost of power generation, polluting the environment, and causing a waste of resources. Therefore, the development and research of efficient separation methods and the implementation of medium coal re-selection are of great significance to the rational utilization of coal resources and environmental protection in my country.

High-pressure roller mill is the mainstream in the development of more crushing and less grinding technology and selective crushing technology in the field of mineral processing at home and abroad. The high-pressure roller mill is a new type of crushing equipment designed based on the principle of material layer crushing. The main characteristics of material layer crushing are: the crushing working pressure is high, causing cracks inside the particles, and it has a certain selective crushing effect, which can improve the product’s resolution. degree of separation. Other advantages can be summarized as follows: large processing capacity, up to 3 400t/h; low unit power consumption, about 20%~50% lower than that of cone crushers, jaw crushers, and rod mills; High work rate, etc.

Contents of the invention

In view of the problems existing in the above-mentioned prior art, the present invention provides a high-pressure roller selective crushing and sorting method for medium coal, which can increase the degree of dissociation of pulverized products, improve the selectability of medium coal after crushing, and ensure the clean coal Under the premise of improving the quality of coal, it can increase the yield of clean coal, reduce the energy consumption of pulverization, and achieve the efficient utilization of coal resources.

A high-pressure roller selective crushing and sorting method for middling coal in the present invention uses a high-pressure roller mill to pulverize the washed coal, and sorts the pulverized products. The steps are as follows:

(1) Crushing the raw coal below the upper limit of the selected particle size suitable for the subsequent coal preparation equipment, entering the desliming screen for desliming, the deslimed coal slime water enters the coal slime water treatment system, and the deslimed raw coal undergoes gravity separation I to obtain Clean coal Ⅰ, medium coal Ⅰ and gangue Ⅰ;

(2) The medium coal I is crushed to be below the upper limit of the crushing particle size suitable for the high-pressure roller mill, and the high-pressure roller mill is ultra-finely crushed. When the high-pressure roller mill is working, the pressure between the rollers is 4~6MPa, and the roller speed is 1~3m/min. The roll gap is 2~30mm, and the ultra-fine crushed products of the high-pressure roller mill shall be sieved with a sieve with a sieve of 25mm, 13mm, 6mm or 3mm. The lower material is deslimed, and the deslimed product is subjected to gravity separation II to obtain clean coal II, medium coal II and gangue II after medium coal crushing and re-selection, medium coal II is returned to the high-pressure roller mill and combined with medium coal I Then crush and sort;

(3) The deslimed coal slime water enters the coal slime water treatment system, first enters the thickener, the overflow of the thickener enters the circulating pool, the bottom flow of the thickener undergoes flotation after slurry pretreatment, and the flotation tailing coal enters the tailing coal thickener , the clean coal enters the clean coal filter press, the filter press product is the flotation clean coal, and the filtrate returns to the slurry tank; the tail coal thickener overflows into the circulating pool, the underflow enters the tail coal filter press, and the tail coal press filtrate enters the Circulating pool, filter press products are tailing coal products.

In the step (1), the upper limit of the selected particle size of the subsequent coal preparation equipment is 50-200 mm.

In the step (1), the raw coal crushing equipment is a double-toothed roller crusher, a jaw crusher, an impact crusher or a ring hammer crusher.

In the step (1), the equipment used in the gravity separation I is a jig separator, an inclined wheel heavy medium separator, a vertical wheel heavy medium separator, a shallow groove dense medium separator or a dense medium cyclone .

In the step (2), the upper limit of the crushing particle size of the high pressure roller mill is 50-100 mm.

In the step (2), the material suitable for re-selection after the medium coal I is pulverized by high-pressure rollers can be returned to the re-selection I for sorting, or can be separately processed for the re-selection II.

In the step (2), the equipment used in the gravity separation II is a dense medium cyclone, a spiral separator, a TBS disturbed bed separator or a countercurrent separator.

In the step (3), a ball mill can be added before the slime flotation to improve the quality and yield of the flotation clean coal.

In described step (3), for the situation that coal slime is not suitable for flotation, the coal slime water after desliming enters concentrator, and concentrator overflow enters circulating pool, and concentrator underflow enters filter press, and filter press filtrate enters circulation Pool and filter press products are slime products.

Compared with the traditional crushing and sorting process of medium coal, the invention has a high-pressure roller selective crushing and separation method for medium coal, which has a high degree of product dissociation, good follow-up gravity separation effect, and improves the separation accuracy of the equipment. Under the premise of ensuring the quality of clean coal, the yield of clean coal can be increased, the cost of coal transportation can be reduced, coal resources can be fully and reasonably recovered and utilized, and resource waste can be reduced.

Description of drawings

Fig. 1 is the technological process schematic diagram of the inventive method;

Fig. 2 is the process flow sheet of the embodiment of the present invention 1,2,4,5;

Fig. 3 is the process flow chart of embodiment 3 of the present invention.

Detailed ways

Example 1

The raw coal is coking coal with an ash content of 18.59%. The coal washing plant is a mine-type coal washing plant with a processing capacity of 4 million t/a. The high-pressure roller mill is used to carry out ultra-fine crushing of medium coal and then sorting. The process steps are as follows:

(1) Raw coal enters a sieve with a sieve hole of 200mm. The material on the sieve is crushed by a double-toothed roller crusher and combined with the material under the sieve, and then enters a desliming sieve with a sieve hole of 0.5mm. The material on the mud sieve enters the vertical wheel heavy-medium separator, and the clean coal I, medium coal I and gangue I are sorted out, and the clean coal I is transported to the clean coal bunker, and the gangue I is transported to the gangue hill;

(2) Midcoal Ⅰ enters a sieve with a sieve hole of 50mm. The material on the sieve is crushed by a jaw crusher and combined with the material under the sieve for ultra-fine crushing by high-pressure roller milling. The pressure between the rollers is 5.0MPa during work, and the roller speed is 1.6m/min, the roll gap is 6mm; the crushed material enters the sieve with a sieve hole of 6mm, and the material on the sieve is combined with the feed of the high-pressure roller mill for ultra-fine crushing by the high-pressure roller mill, and the material under the sieve enters the sieve with a 0.5 mm desliming screen, slime water to the thickener, the material on the screen enters the three-product dense medium cyclone, sorts out clean coal II, medium coal II and gangue II, clean coal II is transported to the clean coal bin, and gangue II is transported Go to the waste rock; after the combination of China Coal II and China Coal I, carry out high-pressure roller mill ultra-fine crushing, and repeat the operation of step (2);

(3) After the slime water is treated by the thickener, the overflow of the thickener enters the circulating pool, and the bottom flow of the thickener undergoes flotation after slurry pretreatment, and the flotation tailing coal enters the tailing coal thickener, and the clean coal enters the clean coal filter press , the press filter product is flotation clean coal, and the filtrate is returned to the slurry tank; the tailing coal thickener overflows into the circulating pool, the underflow enters the tailing coal filter press, and the tailing coal press filtrate enters the circulating pool, and the press filter product is the floating Select tailing coal.

The yield of clean coal I is 57.54%, and the ash content is 10.41%; the yield of medium coal I is 7.46%, and the ash content is 24.00%; The yield of gangue II was 1.23%, and the ash content was 66.26%; the yield of flotation clean coal was 20.70%, and the ash content was 10.00%; the yield of flotation tailing coal was 7.12%, The ash content is 31.55%. Compared with the traditional crushing and separation process of China Coal, the yield of Clean Coal II can be increased by 1.57%.

Example 2

The raw coal is coking coal with an ash content of 39.75%. The coal washing plant is a group-type central coal washing plant with a processing capacity of 5 million t/a. The high-pressure roller mill is used to carry out ultra-fine crushing of medium coal and then sorting. The process steps are as follows:

(1) Raw coal enters a sieve with a sieve hole of 50mm. The material on the sieve is crushed by a double-toothed roller crusher and combined with the material under the sieve, and then enters a desliming sieve with a sieve hole of 0.5mm. The material on the mud screen enters the three-product dense medium cyclone, and the clean coal I, medium coal I and gangue I are sorted out, the clean coal I is transported to the clean coal bin, and the gangue I is transported to the gangue hill;

(2) China Coal I carries out high-pressure roller mill ultra-fine crushing, the pressure between the rollers is 4.0MPa, the roller speed is 2.0m/min, and the roller gap is 3mm; the crushed material enters the sieve with a sieve hole of 3mm, and the material on the sieve Combined with the high-pressure roller mill for ultra-fine crushing, the material under the sieve enters the desliming sieve with a sieve hole of 0.5mm, the slime water goes to the thickener, and the material on the sieve enters the TBS interference bed separator Ⅰ for separation Clean coal II and medium coal II are selected, medium coal II enters TBS interference bed separator II, medium coal III and gangue II are separated, clean coal II is transported to the clean coal bin, and gangue II is transported to the gangue hill; After Ⅲ is combined with China Coal Ⅰ, carry out high-pressure roller mill ultra-fine crushing, and repeat the operation of step (2);

(3) After the slime water is treated by the thickener, the overflow of the thickener enters the circulating pool, and the bottom flow of the thickener undergoes flotation after slurry pretreatment, and the flotation tailing coal enters the tailing coal thickener, and the clean coal enters the clean coal filter press , the press filter product is flotation clean coal, and the filtrate is returned to the slurry tank; the tailing coal thickener overflows into the circulating pool, the underflow enters the tailing coal filter press, and the tailing coal press filtrate enters the circulating pool, and the press filter product is the floating Select tailing coal.

The yield of clean coal I is 36.64%, and the ash content is 10.11%; the yield of medium coal I is 21.89%, and the ash content is 39.05%; The yield of gangue II was 8.52%, and the ash content was 65.88%; the yield of flotation clean coal was 14.06%, the ash content was 11.00%, and the yield of flotation tailing coal was 10.43%. The ash content is 34.82%. Compared with the traditional crushing and separation process of China Coal, the yield of Clean Coal II can be increased by 1.06%.

Example 3

The raw coal is coking coal with an ash content of 19.40%. The coal washing plant is a mine-type coal washing plant with a processing capacity of 3 million t/a. The high-pressure roller mill is used to carry out ultra-fine crushing of medium coal and then sorting. The process steps are as follows:

(1) Raw coal enters a sieve with a sieve hole of 50 mm. The material on the screen is crushed by a double-toothed roller crusher and combined with the material under the screen to enter the jig separator to separate clean coal I, medium coal I and gangue Ⅰ, clean coal Ⅰ is transported to the clean coal bunker, and gangue Ⅰ is transported to the gangue hill;

(2) China Coal I carries out high-pressure roller mill ultra-fine crushing, the pressure between the rollers is 6.0MPa, the roller speed is 1.0m/min, and the roller gap is 13mm; the crushed material enters the sieve with a sieve hole of 13mm, and the material on the sieve Combined with the high-pressure roller mill, the high-pressure roller mill is used for ultra-fine crushing. The material under the sieve enters the desliming screen with a sieve hole of 0.5mm, the slime water goes to the thickener, and the material on the sieve enters the spiral separator to separate the fine Coal II, medium coal II and gangue II, clean coal II are transported to the clean coal bin, gangue II is transported to the gangue hill; medium coal II and medium coal I are combined for ultra-fine crushing by high-pressure roller mills, and the operation of step (2) is repeated;

(3) After the slime water is treated by the thickener, the overflow of the thickener enters the circulating pool, and the bottom flow of the thickener undergoes flotation after slurry pretreatment, and the flotation tailing coal enters the tailing coal thickener, and the clean coal enters the clean coal filter press , the press filter product is flotation clean coal, and the filtrate is returned to the slurry tank; the tailing coal thickener overflows into the circulating pool, the underflow enters the tailing coal filter press, and the tailing coal press filtrate enters the circulating pool, and the press filter product is the floating Select tailing coal.

The yield of clean coal I is 57.44%, and the ash content is 9.92%; the yield of medium coal I is 10.90%, and the ash content is 21.84%; The yield of gangue II was 1.72%, and the ash content was 62.13%; the yield of flotation clean coal was 16.31%, and the ash content was 10.00%; the yield of flotation tailing coal was 9.32%, The ash content is 30.49%. Compared with the traditional crushing and separation process of China Coal, the yield of Clean Coal II can be increased by 1.38%.

Example 4

The raw coal is coking coal with an ash content of 37.99%. The coal washing plant is a mine-type coal washing plant with a processing capacity of 3 million t/a. The high-pressure roller mill is used to carry out ultra-fine crushing of medium coal and then sorting. The process steps are as follows:

(1) Raw coal enters a sieve with a sieve hole of 50mm. The material on the sieve is crushed by a double-toothed roller crusher and combined with the material under the sieve, and then enters a desliming sieve with a sieve hole of 0.5mm. The material on the mud sieve enters the slanted wheel heavy-medium separator to separate clean coal I, medium coal I and gangue I, clean coal I is transported to the clean coal bunker, and gangue I is transported to the gangue hill;

(2) China Coal I carries out high-pressure roller mill ultra-fine crushing, the pressure between the rollers is 5.0MPa during work, the roller speed is 3.0m/min, and the roller gap is 3mm; the crushed materials enter the sieve with a sieve hole of 3mm, and the materials on the sieve Combined with the high-pressure roller mill feeding materials for high-pressure roller mill ultra-fine crushing, the material under the sieve enters the desliming sieve with a sieve hole of 0.5mm, the slime water goes to the thickener, and the material on the sieve enters the three-product dense medium cyclone for separation Select clean coal II, medium coal II and gangue II, clean coal II is transported to the clean coal bin, and gangue II is transported to the gangue hill; medium coal II and medium coal I are combined and then subjected to high-pressure roller milling for ultra-fine crushing, repeating step (2) operation;

(3) After the coal slime water is treated by the thickener, the overflow of the thickener enters the circulating pool, and the bottom flow of the thickener enters the ball mill for grinding after the slurry pretreatment, and the ground product undergoes flotation after the slurry treatment. The tailing coal enters the tailing coal thickener, the clean coal enters the clean coal filter press, and the filter press product is flotation clean coal, and the filtrate returns to the slurry tank; the tail coal thickener overflows into the circulating pool, and the underflow enters the tailing coal filter press , the tailing coal press filter filtrate enters the circulating pool, and the press filter product is the flotation tailing coal.

The yield of clean coal I is 42.32%, and the ash content is 8.43%; the yield of medium coal I is 12.64%, and the ash content is 26.03%; The yield of gangue II was 2.92%, and the ash content was 8.78%. The yield of gangue II was 2.52%, and the ash content was 67.48%. The yield of flotation clean coal was 13.05%, and the ash content was 8.42%. The ash content is 34.66%. Compared with the traditional crushing and separation process of China Coal, the yield of Clean Coal II can be increased by 1.15%.

Example 5

The raw coal is thermal coal with an ash content of 26.81%. The type of coal washing plant is a mine-type coal washing plant with a processing capacity of 16 million t/a. The high-pressure roller mill is used to carry out ultra-fine crushing of medium coal and then sorting. The process steps are as follows:

(1) Raw coal enters a sieve with a sieve hole of 200mm. The material on the sieve is crushed by a double-toothed roller crusher and combined with the material under the sieve, and then enters a desliming sieve with a sieve hole of 0.5mm. The material on the mud screen enters the three-product dense medium cyclone, and the clean coal I, medium coal I and gangue I are sorted out, the clean coal I is transported to the clean coal bin, and the gangue I is transported to the gangue hill;

(2) Midcoal I enters a sieve with a sieve hole of 100mm. The material on the sieve is crushed by a jaw crusher and combined with the material under the sieve for ultra-fine crushing by high-pressure roller milling. The pressure between the rollers is 5.5MPa during work, and the roller speed is 2.0m/min, the roll gap is 25mm; the crushed material enters a sieve with a sieve hole of 25mm, the material on the sieve is combined with the feed of the high-pressure roller mill for ultra-fine crushing by the high-pressure roller mill, and the material under the sieve enters the sieve with a 0.5 mm desliming screen, slime water to the thickener, the material on the screen enters the three-product dense medium cyclone, sorts out clean coal II, medium coal II and gangue II, clean coal II is transported to the clean coal bin, and gangue II is transported Go to the waste rock; after the combination of China Coal II and China Coal I, carry out high-pressure roller mill ultra-fine crushing, and repeat the operation of step (2);

(3) After the slime water is treated by the concentrator, the overflow of the concentrator enters the circulating pool, the underflow of the concentrator enters the filter press, and the filter press filtrate enters the circulating pool, and the filter press product is a coal slime product.

The yield of clean coal I is 43.06%, and the ash content is 8.39%; the yield of medium coal I is 29.74%, and the ash content is 24.86%; The yield of gangue II was 10.21%, and the ash content was 8.56%; the yield of gangue II was 3.37%, and the ash content was 78.32%; the yield of coal slime was 29.27%, and the ash content was 27.62%. Compared with the traditional crushing and separation process of China Coal, the yield of Clean Coal II can be increased by 2.45%.

Claims (1)

1. the high pressure roller selective molecular attraction of coal and a method for separating in, carry out according to following steps:

(1) raw coal is crushed to below the feed particle size upper limit being suitable for follow-up cleaning unit, enter desliming screen and carry out desliming, the black water after desliming enters slurry circulating system, and the raw coal after desliming carries out gravity treatment I, obtains cleaned coal I, middle coal I and spoil I; Wherein, the feed particle size upper limit of follow-up cleaning unit is 50 ~ 200mm; Wherein bi-fluted roller type disintegrating machine, jaw crusher, impact breaker or ring hammer disintegrating machine selected by raw coal disintegrating apparatus; The equipment that gravity treatment I adopts is jigging separator, tiltedly takes turns dense media separator, vertical wheel dense media separator or shallow slot dense media separator;

It is characterized in that :

(2) in coal I be crushed to be suitable for high-pressure roller mill the grinding particle size upper limit below, carry out high pressure roller mill ultrafine grinding, during high-pressure roller mill work, roll gap pressure is 4 ~ 6MPa, roller speed is 1 ~ 3m/min, roll gap is 2 ~ 30mm, products application sieve aperture after high pressure roller mill ultrafine grinding is 25mm, 13mm, the sieve of 6mm or 3mm sieves, on-the-sieve material returns high-pressure roller mill and new feed and merges and pulverize, undersize material carries out desliming, product after desliming carries out gravity treatment II, obtain the cleaned coal II after the broken choosing again of coal dust, middle coal II and spoil II, middle coal II returns high-pressure roller mill and middle coal I and is merged together and carries out pulverizing and sorting again, wherein, the grinding particle size upper limit of high-pressure roller mill is 50 ~ 100mm, the material that wherein middle coal I is suitable for gravity treatment after high pressure roller is pulverized can turn back to gravity treatment I and carry out sorting, also can carry out separately gravity treatment II process, the equipment that gravity treatment II adopts is heavy medium cyclone, spiral, TBS hindered bed separator or adverse current separator,

(3) black water after desliming enters slurry circulating system, first thickener is entered, thickener overflow enters circulating water pool, thickener underflow carries out flotation after pretreatment of sizing mixing, floating tail-coal enters tail coal thickener, cleaned coal enters clean coal pressur filter, and press filtration product is floatation clean coal, and filtrate returns mixing cirtern; Tail coal thickener overflow enters circulating water pool, and underflow enters tail coal filter press, and tail coal press filtration filtrate enters circulating water pool, and press filtration product is tail coal product.