Coal crushing and separating method and separating device

Abstract

The invention relates to the field of screening method coal separation, in particular to a coal crushing and separating method and a separating device.The separating device comprises a box body, a driving mechanism is arranged on the upper surface of the box body, a crushing mechanism is arranged in the box body, a separating mechanism is arranged in the box body, and a grinding mechanism is arranged in the separating mechanism; a turnover mechanism is arranged in the box body; the driving mechanism comprises a rotating rod, a motor is started to drive equipment to operate, then dried coal is put into the equipment to be crushed, coal powder meeting the standard is filtered and discharged, coal powder not meeting the standard is left and ground, and the ground coal powder meeting the standard is filtered and discharged. And the coal powder which does not meet the standard is left, overturned and lifted to the upper part and ground again until all the coal powder meet the standard, so that the processing of the coal powder is simpler, the mixing is avoided, and the influence on the separation of coal by a screening method is avoided.

Description

Technical Field

[0001] The present invention relates to the field of coal separation by screening method, and specifically relates to a coal crushing and separating method and a separating device. Background Art

[0002] The geological structure in Yili area is complex. During the long geological history period, a large amount of plant remains accumulated in a specific sedimentary environment, and gradually formed raw Yili coal through coalification. Its coal-forming environment affected the material composition and structure of the coal, creating unique properties.

[0003] Screening method for coal separation is an important coal separation method. It mainly determines the particle size composition of coal through screening tests and performs separation accordingly. The screening method usually includes two types: coal screening and coal powder screening. For materials larger than 0.5 mm, the large screening method is used to determine their particle size composition; for materials smaller than 0.5 mm, small screening (standard set of sieves) is used to determine the particle size composition of pulverized coal. This method can understand the quality characteristics of products in each particle size grade, and provide basic data and technical basis for mine design, coal preparation plant design, separation effect and economic benefits of the coal preparation process.

[0004] When the existing coal crushing and separating equipment is in use, usually the raw coal is first crushed by a crusher, the crushed coal sample is placed in an oven and completely dried (110°C - 12 h), and the dried coal sample is sieved through a 200-mesh sieve (0.074 mm). The coal sample larger than 0.074 mm is put into a pulverizer and ground for 10 s (to prevent excessive crushing), the coal sample after pulverization is sieved through a 200-mesh sieve again, and this process is repeated until all the coal powder can pass through the sieve after the coal sample is sieved through a 200-mesh sieve for the last time. After the sixth sieve, it can pass through completely. And in this process, the coal powder is divided into multiple portions and transferred multiple times in each machine, making the overall operation process cumbersome and prone to mixing, which is very inconvenient to use. Therefore, it is necessary to propose a coal crushing and separating method and a separating device. Summary of the Invention

[0005] Aiming at the problems in the prior art, the present invention provides a coal crushing and separating method and a separating device.

[0006] The technical solution adopted by the present invention to solve its technical problems is: a coal crushing and separating device, including a box body, a driving mechanism is arranged on the upper surface of the box body, a crushing mechanism is arranged inside the box body, a separating mechanism is arranged inside the box body, a grinding mechanism is arranged inside the separating mechanism, and a flipping mechanism is arranged inside the box body;

[0007] The driving mechanism includes a rotating rod, which is rotatably connected to the upper surface of the box body through a bearing. The upper ends of the rotating rods all extend outside the box body and are fixedly connected with first driven gears. A first motor is fixedly installed on the upper surface of the box body, and the output end of the first motor is fixedly connected with a first driving gear through a coupling. The first driving gear meshes with the first driven gear;

[0008] The crushing mechanism includes a processing cavity, which is opened inside the box body. The lower end of the rotating rod extends into the processing cavity, and a crushing knife is fixedly installed on the rod wall of the rotating rod located inside the processing cavity. A feed pipe is fixedly installed on the upper cavity wall of the processing cavity, and a discharge hole is penetrated through the bottom cavity wall of the processing cavity;

[0009] The separating mechanism includes a filter plate, which is fixedly installed on the cavity wall of the processing cavity. A connecting hole is penetrated through the cavity wall of the processing cavity, and a filter screen cylinder is fixedly installed on the hole wall of the connecting hole. A feed hole is penetrated through the upper end of the filter screen cylinder;

[0010] The grinding mechanism includes a fixing block, and a grinding hole is penetrated through the inside of the fixing block. A fixing frame is fixedly installed at the middle of the grinding hole, and a double-headed driving motor is fixedly installed on the fixing frame. The output end of the double-headed driving motor is fixedly installed with a grinding block through a coupling;

[0011] The flipping mechanism includes an installation groove, which is opened inside the box body on one side of the filter screen cylinder. The outer side wall of the filter screen cylinder is rotatably connected with an installation rod through a bearing. One end of the installation rod extends into the filter screen cylinder and is fixedly connected with the fixing block. The other end of the installation rod extends into the installation groove and is fixedly connected with a second driven gear. A second motor is fixedly installed in the installation groove, and the output end of the second motor is fixedly connected with a second driving gear through a coupling. The second driving gear meshes with the second driven gear.

[0012] Preferably, the connecting hole is arranged in a U shape. The upper hole opening of the connecting hole is communicated with the inner cavity of the processing cavity above the filter plate, and the lower hole opening of the connecting hole is communicated with the inner cavity of the processing cavity below the filter plate.

[0013] Preferably, a storage groove is opened on the grinding block, and both ends of the double-headed driving motor are sleeved in the storage groove.

[0014] Preferably, an installation frame is fixedly installed on the outer side wall of the first motor, and the first motor is fixedly installed on the upper surface of the box body through the installation frame.

[0015] Preferably, the upper end of the feed pipe extends outside the box body, and a feed funnel is fixedly connected to the upper end of the feed pipe.

[0016] Preferably, the feed pipe is arranged above the crushing knife.

[0017] Preferably, the fixing block is arranged in a disc shape and is rotatably connected inside the filter screen cylinder.

[0018] A coal crushing and separating method includes the following steps:

[0019] First step: Select the raw Yili coal, use a hammer crusher to crush the raw Yili coal once, crush it into small pieces of Yili coal with a diameter < 4CM, so as to facilitate drying of the internal moisture. Then put the crushed small pieces of Yili coal into a drying chamber at 80°C and dry for 12h. The dried small pieces of Yili coal will not adhere to the filter plate and the filter screen cylinder during grinding;

[0020] Second step: Start the first motor and the double-headed drive motor. The first motor will drive the first driving gear to rotate. The first driving gear can drive the rotating rod to rotate through meshing with the first driven gear, and the rotating rod will drive the two groups of crushing knives to rotate. The double-headed drive motor will drive the grinding block to rotate;

[0021] Third step: Pour the dried small pieces of Yili coal into the feed hopper. The small pieces of Yili coal in the feed hopper will fall into the processing cavity through the feed pipe. The two groups of crushing knives will crush the small pieces of Yili coal. The crushed coal powder will be filtered by the filter plate with 200 meshes. The coal powder with a particle size < 0.074mm will pass through the filter, and the passed coal powder will fall to the bottom of the processing cavity, and then slide to one side along the slope and be discharged through the discharge hole;

[0022] Fourth step: The coal powder with a particle size > 0.074mm will be left on the filter plate, and then slide along the inclined filter plate. The sliding coal powder will enter the connecting hole, and then enter the filter screen cylinder through the feed hole. The coal powder entering the filter screen cylinder will enter the grinding holes on the fixing block. When the grinding block rotates, it will grind the coal powder in the grinding holes;

[0023] Fifth step: The ground coal powder will fall to the bottom of the filter screen cylinder, and then be filtered by the filter screen cylinder with 200 meshes. The coal powder with a particle size < 0.074mm will pass through the filter, fall to the bottom of the connecting hole, slide to the bottom of the processing cavity, and then slide to one side along the slope and be discharged through the discharge hole;

[0024] Step 6: Coal powder with a particle size > 0.074 mm will be retained inside the filter mesh cylinder and accumulate at the bottom of the grinding holes. At this time, start the second motor, which will drive the second driving gear to rotate. Through the meshing with the second driven gear, the second driving gear can drive the mounting rod to rotate, and the mounting rod drives the fixing block and the grinding holes to turn over, so that the coal powder originally at the bottom of the grinding holes is driven to the top and then slides down into the grinding holes on the fixing block. When the grinding block rotates, it will grind the coal powder in the grinding holes, and the coal powder with a particle size < 0.074 mm will be discharged through the process of Step 5;

[0025] Step 7: After that, the process of Step 6 can be repeated to repeatedly turn over the fixing block and the grinding holes to repeatedly grind the unqualified coal powder until all the coal powder meets the standard of a particle size < 0.074 mm, and then it can be discharged after being ground.

[0026] Advantages of the present invention: For the coal crushing and separation method and separation device described in the present invention, when in use, first start the motor to drive the equipment to run, and then put the dried coal into the equipment for crushing. The qualified coal powder is filtered and discharged, the unqualified coal powder is left for grinding, and the qualified coal powder after grinding is filtered and discharged. The unqualified coal powder is left, turned over and lifted to the upper part and ground again until all meet the standards, making the processing of coal powder simpler and without mixing, thus avoiding affecting the separation of coal by the screening method. Description of the Drawings

[0027] The present invention will be further described below with reference to the drawings and embodiments.

[0028] Figure 1 It is a front view structural schematic diagram of a coal crushing and separation method and separation device provided by the present invention;

[0029] Figure 2 It is a Figure 1 top view schematic diagram at A - A of the coal crushing and separation method and separation device provided by the present invention;

[0030] Figure 3 It is a Figure 1 top view internal schematic diagram at B - B of the coal crushing and separation method and separation device provided by the present invention;

[0031] Figure 4 It is a rear view internal schematic diagram of a coal crushing and separation method and separation device provided by the present invention;

[0032] Figure 5 It is a flipped - state structural schematic diagram of a coal crushing and separation method and separation device provided by the present invention;

[0033] Figure 6 Schematic diagram of the internal structure of the box body after removing the fixing block for a coal crushing and separation method and separation device provided by the present invention;

[0034] Figure 7 Schematic diagram of the internal structure of the fixing block for a coal crushing and separation method and separation device provided by the present invention.

[0035] In the figure: 1, box body; 21, rotating rod; 22, first driven gear; 23, first motor; 24, first driving gear; 25, mounting frame; 31, processing chamber; 32, crushing knife; 33, feed pipe; 34, feed funnel; 35, discharge hole; 41, filter plate; 42, connecting hole; 43, filter net cylinder; 44, feed hole; 51, fixing block; 52, grinding hole; 53, fixing frame; 54, double-headed driving motor; 55, grinding block; 56, storage groove; 61, mounting groove; 62, mounting rod; 63, second driven gear; 64, second motor; 65, second driving gear. Specific embodiments

[0036] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0037] As Figures 1-7 shown, a coal crushing and separation device according to the present invention includes a box body 1, a driving mechanism is arranged on the upper surface of the box body 1, a crushing mechanism is arranged inside the box body 1, a separation mechanism is arranged inside the box body 1, a grinding mechanism is arranged inside the separation mechanism, and a flipping mechanism is arranged inside the box body 1;

[0038] The driving mechanism includes a rotating rod 21, the rotating rod 21 is rotatably connected to the upper surface of the box body 1 through a bearing, the upper ends of the rotating rod 21 all extend outside the box body 1 and are fixedly connected with first driven gears 22, a first motor 23 is fixedly installed on the upper surface of the box body 1, and the output end of the first motor 23 is fixedly connected with a first driving gear 24 through a coupling, and the first driving gear 24 meshes with the first driven gear 22;

[0039] The crushing mechanism includes a processing chamber 31, the processing chamber 31 is opened inside the box body 1, the lower end of the rotating rod 21 extends into the processing chamber 31, and a crushing knife 32 is fixedly installed on the rod wall of the rotating rod 21 located inside the processing chamber 31, a feed pipe 33 is fixedly installed on the upper end wall of the processing chamber 31, and a discharge hole 35 is penetrated through the bottom end wall of the processing chamber 31;

[0040] The separating mechanism includes a filter plate 41 which is fixedly installed on the cavity wall of the processing cavity 31. A connecting hole 42 is penetrated and opened on the cavity wall of the processing cavity 31. A filter net cylinder 43 is fixedly installed on the hole wall of the connecting hole 42. A feed hole 44 is penetrated and opened at the upper end of the filter net cylinder 43;

[0041] The grinding mechanism includes a fixed block 51. A grinding hole 52 is penetrated and opened inside the fixed block 51. A fixed frame 53 is fixedly installed at the middle of the grinding hole 52. A double-headed driving motor 54 is fixedly installed on the fixed frame 53. The output end of the double-headed driving motor 54 is fixedly installed with a grinding block 55 through a coupling;

[0042] The flipping mechanism includes an installation groove 61 which is opened inside the box body 1 on one side of the filter net cylinder 43. The outer side wall of the filter net cylinder 43 is rotationally connected with an installation rod 62 through a bearing. One end of the installation rod 62 extends into the filter net cylinder 43 and is fixedly connected with the fixed block 51. The other end of the installation rod 62 extends into the installation groove 61 and is fixedly connected with a second driven gear 63. A second motor 64 is fixedly installed inside the installation groove 61. The output end of the second motor 64 is fixedly connected with a second driving gear 65 through a coupling. The second driving gear 65 meshes with the second driven gear 63.

[0043] Among them, the connecting hole 42 is arranged in a U shape. The upper hole opening of the connecting hole 42 is communicated with the inner cavity of the processing cavity 31 above the filter plate 41, and the lower hole opening of the connecting hole 42 is communicated with the inner cavity of the processing cavity 31 below the filter plate 41. A storage groove 56 is opened on the grinding block 55. Both ends of the double-headed driving motor 54 are sleeved inside the storage groove 56. An installation frame 25 is fixedly installed on the outer side wall of the first motor 23. The first motor 23 is fixedly installed on the upper surface of the box body 1 through the installation frame 25. The upper end of the feed pipe 33 extends outside the box body 1. The upper end of the feed pipe 33 is fixedly connected with a feed funnel 34. The feed pipe 33 is arranged above the crushing knife 32. The fixed block 51 is arranged in a disc shape and is rotationally connected inside the filter net cylinder 43.

[0044] A coal crushing and separating method includes the following steps:

[0045] The first step: Select the raw Yili coal. Use a hammer crusher to crush the raw Yili coal once to crush it into small pieces of Yili coal with a diameter < 4CM, so as to facilitate the drying of the internal moisture. Then put the crushed small pieces of Yili coal into a drying room at 80 °C and dry for 12h. The dried small pieces of Yili coal will not adhere to the filter plate 41 and the filter net cylinder 43 during grinding;

[0046] Step 2: Start the first motor 23 and the double-headed drive motor 54. The first motor 23 will drive the first driving gear 24 to rotate. The first driving gear 24 can drive the rotating rod 21 to rotate through meshing with the first driven gear 22. The rotating rod 21 will drive the two groups of crushing knives 32 to rotate. The double-headed drive motor 54 will drive the grinding block 55 to rotate;

[0047] Step 3: Pour the dried small pieces of Ili coal into the feeding funnel 34. The small pieces of Ili coal in the feeding funnel 34 will fall into the processing chamber 31 through the feeding pipe 33. The two groups of crushing knives 32 will crush the small pieces of Ili coal. The crushed coal powder will be filtered through the filter plate 41 of the 200-mesh sieve. The coal powder with a particle size < 0.074 mm will pass through the filter. The passed coal powder will fall to the bottom of the processing chamber 31, and then slide to one side along the slope and be discharged through the discharge hole 35;

[0048] Step 4: The coal powder with a particle size > 0.074 mm will be left on the filter plate 41, and then slide along the inclined filter plate 41. The sliding coal powder will enter the connecting hole 42, and then enter the filter mesh cylinder 43 through the feeding hole 44. The coal powder entering the filter mesh cylinder 43 will enter the grinding hole 52 on the fixed block 51. When the grinding block 55 rotates, it will grind the coal powder in the grinding hole 52;

[0049] Step 5: The ground coal powder will fall to the bottom of the filter mesh cylinder 43, and then be filtered through the filter mesh cylinder 43 of the 200-mesh sieve. The coal powder with a particle size < 0.074 mm will pass through the filter, fall to the bottom of the connecting hole 42, slide to the bottom of the processing chamber 31, and then slide to one side along the slope and be discharged through the discharge hole 35;

[0050] Step 6: The coal powder with a particle size > 0.074 mm will be left in the filter mesh cylinder 43 and gather at the bottom of the grinding hole 52. At this time, start the second motor 64. The second motor 64 will drive the second driving gear 65 to rotate. The second driving gear 65 can drive the mounting rod 62 to rotate through meshing with the second driven gear 63. The mounting rod 62 drives the fixed block 51 and the grinding hole 52 to flip, so that the coal powder originally at the bottom of the grinding hole 52 is driven to the top and slides down into the grinding hole 52 on the fixed block 51. When the grinding block 55 rotates, it will grind the coal powder in the grinding hole 52. The coal powder with a particle size < 0.074 mm will be discharged through the process of Step 5;

[0051] Step 7: After that, the sixth-step process can be repeated, the fixing block 51 and the grinding hole 52 can be repeatedly flipped, the unqualified coal powder can be repeatedly ground, and until all the coal powder meets the standard of powder particle size < 0.074mm, it can be discharged after being ground.

[0052] Table 1 shows the internal microscopic component distribution of small pieces of Yili coal after drying:

[0053]

[0054] Table 2 shows the Raman spectrum fitting parameters of microscopic components of coal powder at different particle sizes:

[0055]

[0056] Table 3 shows the microscopic component distribution of Yili coal at different crushing particle sizes:

[0057]

[0058] Table 4 shows the microscopic component distribution of coal rock of Yili coal at different grinding times:

[0059]

[0060] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope claimed by the present invention. The scope claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A coal crushing and separating device, comprising a box body (1), characterized in that, A driving mechanism is provided on the upper surface of the box body (1), a crushing mechanism is provided inside the box body (1), a separating mechanism is provided inside the box body (1), a grinding mechanism is provided inside the separating mechanism, and a flipping mechanism is provided inside the box body (1); The driving mechanism includes a rotating rod (21); The crushing mechanism includes a processing cavity (31) which is opened inside the box body (1). The lower end of the rotating rod (21) extends into the processing cavity (31), and a crushing knife (32) is fixedly installed on the rod wall of the rotating rod (21) inside the processing cavity (31); The separating mechanism includes a filter plate (41) which is fixedly installed on the cavity wall of the processing cavity (31). A connecting hole (42) is penetrated through the cavity wall of the processing cavity (31), a filter screen cylinder (43) is fixedly installed on the hole wall of the connecting hole (42), and a feeding hole (44) is penetrated through the upper end of the filter screen cylinder (43); The grinding mechanism includes a fixed block (51). A grinding hole (52) is penetrated through the fixed block (51). A fixed frame (53) is fixedly installed in the middle of the grinding hole (52). A double-headed driving motor (54) is fixedly installed on the fixed frame (53), and a grinding block (55) is fixedly installed at the output end of the double-headed driving motor (54) through a coupling; The flipping mechanism includes an installation groove (61) which is opened inside the box body (1) on one side of the filter screen cylinder (43). The outer side wall of the filter screen cylinder (43) is rotationally connected with an installation rod (62) through a bearing. One end of the installation rod (62) extends into the filter screen cylinder (43) and is fixedly connected with the fixed block (51).

2. The coal crushing and separating device according to claim 1, wherein: The connecting hole (42) is arranged in a U shape. The upper end hole of the connecting hole (42) is communicated with the inner cavity of the processing cavity (31) above the filter plate (41), and the lower end hole of the connecting hole (42) is communicated with the inner cavity of the processing cavity (31) below the filter plate (41).

3. A coal crushing and separating device according to claim 1, characterized in that: A receiving groove (56) is opened on the grinding block (55). Both ends of the double-headed driving motor (54) are sleeved in the receiving groove (56). The fixed block (51) is arranged in a disc shape and is rotationally connected inside the filter screen cylinder (43).

4. A coal crushing and separating device according to claim 1, characterized in that: The rotating rod (21) is rotationally connected to the upper surface of the box body (1) through a bearing. The upper ends of the rotating rods (21) all extend outside the box body (1) and are fixedly connected with first driven gears (22). A first motor (23) is fixedly installed on the upper surface of the box body (1). The output end of the first motor (23) is fixedly connected with a first driving gear (24) through a coupling. The first driving gear (24) is meshed with the first driven gear (22).

5. A coal crushing and separating device according to claim 4, characterized in that: An installation frame (25) is fixedly installed on the outer side wall of the first motor (23). The first motor (23) is fixedly installed on the upper surface of the box body (1) through the installation frame (25).

6. The coal crushing and separating device according to claim 1, wherein: A feed pipe (33) is fixedly installed on the upper cavity wall of the processing cavity (31). A discharge hole (35) is penetrated and opened on the bottom cavity wall of the processing cavity (31). The upper end of the feed pipe (33) extends outside the box body (1). The upper end of the feed pipe (33) is fixedly connected with a feed hopper (34). The feed pipe (33) is arranged above the crushing knife (32).

7. A coal crushing and separating device according to claim 1, characterized in that: The other end of the mounting rod (62) extends into the mounting groove (61) and is fixedly connected with a second driven gear (63). A second motor (64) is fixedly installed in the mounting groove (61). The output end of the second motor (64) is fixedly connected with a second driving gear (65) through a coupling. The second driving gear (65) is meshed with the second driven gear (63).

8. A coal crushing and separation method according to any one of claims 1-7, characterized in that, Including the following steps: The first step: Select the raw Yili coal. Use a hammer crusher to crush the raw Yili coal for the first time to crush it into small pieces of Yili coal with a diameter < 4CM, so as to facilitate the drying of the internal moisture. Then put the crushed small pieces of Yili coal into a drying room at 80°C and dry for 12h. The dried small pieces of Yili coal will not adhere to the filter plate (41) and the filter mesh cylinder (43) during grinding; The second step: Start the first motor (23) and the double-headed driving motor (54). The first motor (23) will drive the first driving gear (24) to rotate. The first driving gear (24) can drive the rotating rod (21) to rotate through the meshing with the first driven gear (22). The rotating rod (21) will drive the two groups of crushing knives (32) to rotate. The double-headed driving motor (54) will drive the grinding block (55) to rotate; The third step: Pour the dried small pieces of Yili coal into the feed hopper (34). The small pieces of Yili coal in the feed hopper (34) fall into the processing cavity (31) through the feed pipe (33). The two groups of crushing knives (32) will crush the small pieces of Yili coal. The crushed coal powder will be filtered by the filter plate (41) with 200 meshes. The coal powder with a particle size < 0.074mm will pass through the filter. The passed coal powder will fall to the bottom of the processing cavity (31), and then slide to one side along the slope and be discharged through the discharge hole (35); The fourth step: The coal powder with a particle size > 0.074mm will be left on the filter plate (41), and then slide along the inclined filter plate (41). The sliding coal powder will enter the connecting hole (42), and then enter the filter mesh cylinder (43) through the feed hole (44). The coal powder entering the filter mesh cylinder (43) will enter the grinding hole (52) on the fixed block (51). When the grinding block (55) rotates, it will grind the coal powder in the grinding hole (52); Step 5: The ground coal powder will fall to the bottom of the filter screen cylinder (43), and then pass through the filter screen of the 200-mesh filter screen cylinder (43). The coal powder with a particle size < 0.074 mm will pass through the filter and fall to the bottom of the connecting hole (42), and then slide to the bottom of the processing chamber (31), and then slide to one side along the slope and be discharged through the discharge hole (35); Step 6: The coal powder with a particle size > 0.074 mm will be left in the filter screen cylinder (43) and gather at the bottom of the grinding hole (52). At this time, start the second motor (64). The second motor (64) will drive the second driving gear (65) to rotate. The second driving gear (65) can drive the mounting rod (62) to rotate through meshing with the second driven gear (63). The mounting rod (62) drives the fixing block (51) and the grinding hole (52) to turn over, so that the coal powder originally located at the bottom of the grinding hole (52) is driven to the top and slides down into the grinding hole (52) on the fixing block (51). When the grinding block (55) rotates, it will grind the coal powder in the grinding hole (52). The coal powder with a particle size < 0.074 mm will be discharged through the process of Step 5; Step 7: After that, the process of Step 6 can be repeated, and the fixing block (51) and the grinding hole (52) are repeatedly turned over to repeatedly grind the unqualified coal powder until all the coal powder meets the standard of a particle size < 0.074 mm, and then it can be discharged after being ground.

Images