CN111250238A

CN111250238A - Limestone fine grinding device

Info

Publication number: CN111250238A
Application number: CN202010054257.0A
Authority: CN
Inventors: 谈志强
Original assignee: Suzhou Tuona Superfine Powder Co ltd
Current assignee: Suzhou Tuona Superfine Powder Co ltd
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2020-06-09

Abstract

The invention relates to a limestone fine grinding device, which relates to the technical field of limestone processing and comprises a primary grinding box, wherein two grinding rollers which are parallel to each other are arranged in the primary grinding box, a first motor is arranged on the outer side wall of the primary grinding box, the driving end of the first motor is connected with the grinding rollers through a driving belt, the limestone fine grinding device further comprises a secondary grinding box and a feeding box, the feeding box is communicated with the primary grinding box and the secondary grinding box, and a screening plate which is used for screening limestone powder with a smaller particle size to the primary grinding box and conveying limestone powder with a larger particle size to the secondary grinding box is obliquely arranged in the feeding box. The limestone powder processing method can directly obtain limestone powder with a single particle size or a mixture of limestone powders with different particle sizes according to actual needs, is convenient and quick to process, avoids the situation that limestone needs to be repeatedly processed to obtain limestone powders with different particle sizes, effectively improves the working efficiency, and ensures the product quality.

Description

Limestone fine grinding device

Technical Field

The invention relates to the technical field of limestone processing, in particular to a limestone fine grinding device.

Background

Limestone is a common non-metal mineral product, has wide application, and is accumulated in the aspects of limestone utilization and deep processing by related enterprises at home and abroad at present. The limestone after physical processing has the following common uses: 1) the most common method is to produce portland cement, and the general limestone can meet the requirements of cement raw materials after crushing and grinding; 2) the coating-grade heavy calcium carbonate product for high-grade papermaking is produced, more than 90 percent of crushed limestone with the grain size smaller than 2um is suitable for a neutral sizing papermaking process, and more than 50 percent of limestone powder mixture with the grain size smaller than 2um is suitable for the filler of coated paper; 3) the mineral powder with the average particle size of 10-15um is used as a coating filler, the mineral powder with the average particle size of less than 10um is used as a filler for plastics, rubber and papermaking, and the mineral powder with the average particle size of less than 5um is used as an ink filler after activation treatment; 4) producing foundry sand for machine manufacturing, wherein the granularity of the foundry sand produced by limestone is 28-75 meshes; 5) the production of the desulfurization absorbent requires that the limestone be crushed to 0-2 um.

Before the limestone is used, the limestone needs to be subjected to crushing and grinding treatment to reduce the particle size of the limestone and reduce the hardness of the limestone, so that the particle size is suitable for different purposes. The existing enterprises generally grind the limestone fragments by using a grinding machine 1 as shown in fig. 1, wherein the grinding machine 1 generally comprises a box body 2, a material conveying port 21 is arranged at the top of the box body 2, a material feeding port 22 is arranged at the bottom of the box body 2, two parallel pressure rollers 23 are arranged in the box body 2, and the end parts of the pressure rollers 23 penetrate through the box body 2 and are connected with a driving motor 24 through a driving belt 25. When in use, the two pressure rollers 23 rotate simultaneously to grind the limestone fragments to be crushed into powder, thereby reducing the particle size of the limestone and enabling the limestone to meet the production requirements of enterprises.

The above prior art solutions have the following drawbacks: the existing grinding machine 1 has single function, only single one-time grinding can be carried out, the particle size of the produced limestone powder is single, if limestone powder with different particle sizes is needed, the produced limestone powder needs to be put into other grinding machines 1 again for multiple processing, so that limestone powder with smaller particle sizes is obtained, the operation is inconvenient, the overall efficiency is low, and the product quality is not high.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a limestone fine grinding device which can effectively grind limestone, can directly produce limestone powder with different particle sizes, effectively improves the working efficiency and ensures the product quality.

The above object of the present invention is achieved by the following technical solutions:

the utility model provides a lime stone grinder that becomes more meticulous, includes the one-level and grinds the case, the one-level is ground the incasement and is equipped with two grinding rollers that are parallel to each other, the lateral wall that the one-level ground the case is equipped with first motor, the drive end of first motor passes through the drive belt and is connected with grinding roller, still includes second grade grinding case and feeding case, feeding case intercommunication and one-level grinding case and second grade grinding case, the feeding incasement slope is equipped with the screening board that is used for sieving the lime stone powder of fine particle diameter to the one-level grinding case, will carry the lime stone powder of coarser particle diameter to second grade grinding case.

By adopting the technical scheme, after the limestone fragments are put into the feeding box, under the screening of the screening plate, limestone with a smaller particle size in the limestone fragments falls into the primary grinding box, limestone with a larger particle size falls into the secondary grinding box, and the limestone is ground and processed by the primary grinding box and the secondary grinding box so as to obtain limestone powder with different particle sizes. Compared with the prior art, the scheme can directly obtain the limestone powder with different particle sizes, is convenient and quick to process, and avoids the condition that the limestone powder needs to be put into other grinding boxes again to obtain the limestone powder with different particle sizes.

The present invention in a preferred example may be further configured to: a primary discharging pipe communicated with the feeding box is arranged on the side wall of the feeding box, and one end, far away from the feeding box, of the primary discharging pipe is communicated with the secondary grinding box;

the bottom of the feeding box is provided with a primary discharging pipe communicated with the primary grinding box;

rubber springs are arranged on two opposite side walls of the feeding box, one end of each rubber spring is connected to the side wall of the feeding box, and the other end of each rubber spring is connected to the primary grinding box;

the feeding box also comprises a vibration component for driving the feeding box to vibrate.

Through adopting above-mentioned technical scheme, utilize vibrations subassembly drive feeding case to take place vibrations, and then can accelerate the screening board to the screening of lime stone fragment to work efficiency has been improved.

The present invention in a preferred example may be further configured to: the vibration component comprises a vibration motor arranged at the bottom of the feeding box.

Through adopting above-mentioned technical scheme, utilize shock dynamo drive feeding case to take place vibrations to accelerate the screening board to the screening of lime stone fragment, thereby accelerated work efficiency.

The present invention in a preferred example may be further configured to: the discharge end of the second-stage grinding box is communicated with a third-stage grinding box and a fourth-stage grinding box through a conveying device, and the discharge end of the second-stage grinding box is provided with a screening device which is used for screening limestone powder with smaller particle size to the third-stage grinding box and conveying the limestone powder with larger particle size to the fourth-stage grinding box.

By adopting the technical scheme, the limestone powder discharged from the secondary grinding box is conveyed to the tertiary grinding box and the quaternary grinding box through the conveying device, the limestone powder with smaller particle size falls into the tertiary grinding box and the limestone powder with larger particle size falls into the quaternary grinding box by utilizing the screening device, so that the limestone powder is divided into two parts with different particle sizes and then respectively processed, the limestone powder with different particle sizes can be obtained, the condition that the obtained limestone powder needs to be put into the grinding box again for processing is avoided, the operation is simple and rapid, and the quality of products is ensured.

The present invention in a preferred example may be further configured to: the conveying device comprises a conveying pipe communicated with the discharge end of the secondary grinding box, a rotating shaft is arranged in the conveying pipe along the length direction of the conveying pipe, spiral blades are arranged on the peripheral side wall of the rotating shaft, and two ends of the rotating shaft are respectively rotatably connected to two ends of the conveying pipe;

the driving piece is used for driving the rotating shaft to rotate around the axis of the rotating shaft.

Through adopting above-mentioned technical scheme, utilize driving piece drive axis of rotation to drive helical blade and rotate, and then utilize helical blade to promote the limestone flour and remove, thereby can carry the third grade with the limestone flour and grind the incasement with the level four.

The present invention in a preferred example may be further configured to: the driving piece comprises a second motor arranged at one end of the conveying pipe, a plugging plate is arranged at one end of the conveying pipe close to the second-stage grinding box, and one end of the rotating shaft penetrates through the plugging plate and is connected to the driving end of the second motor;

and the peripheral side wall of the conveying pipe is provided with a branch pipe communicated with the three-stage grinding box and the four-stage grinding box.

Through adopting above-mentioned technical scheme, utilize the second motor drive axis of rotation to rotate, and then can carry the limestone flour to tertiary grinding case and level four grinding incasement.

The present invention in a preferred example may be further configured to: the screening device comprises a screening cylinder which is coaxial with the rotating shaft and is positioned in the conveying pipe, and the rotating shaft and the helical blades are both positioned in the screening cylinder;

and a mounting ring for mounting the screening cylinder is arranged in the conveying pipe.

By adopting the technical scheme, the limestone powder with smaller particle size falls into the three-stage grinding box and the limestone powder with larger particle size falls into the four-stage grinding box by utilizing the screening cylinder, so that the limestone powder with different particle sizes is ground and processed respectively, the limestone powder with different particle sizes can be obtained, the working efficiency is effectively improved, and the product quality is ensured.

The present invention in a preferred example may be further configured to: the screening drum comprises a mounting ring, a driven gear ring and a driving gear, wherein the mounting ring is rotatably connected with the two ends of the screening drum;

and a third motor is installed on the outer side wall of the conveying pipe, and the driving end of the third motor is connected to the driving shaft.

Through adopting above-mentioned technical scheme, utilize the third motor drive driving gear to rotate, and then drive driven gear ring and rotate to drive the rotation of screening section of thick bamboo, and then can accelerate the screening section of thick bamboo to the screening of limestone flour, effectively improved work efficiency, ensured product quality.

The present invention in a preferred example may be further configured to: the first-stage grinding box is communicated with a first-stage discharging pipe, the third-stage grinding box is communicated with a third-stage discharging pipe, and the fourth-stage grinding box is communicated with a fourth-stage discharging pipe;

the one-level discharging pipe is equipped with the one-level communicating pipe that communicates with tertiary discharging pipe, tertiary discharging pipe is equipped with the tertiary communicating pipe that communicates with the level four discharging pipe, one-level discharging pipe and one-level communicating pipe all are equipped with first valve, tertiary discharging pipe and tertiary communicating pipe all are equipped with the third valve.

By adopting the technical scheme, the opening and closing of the first valve and the third valve are controlled, so that the limestone powder discharged from the first-stage grinding box, the third-stage grinding box and the fourth-stage grinding box can be mixed according to enterprise requirements, and the produced limestone powder is suitable for different application requirements.

In summary, the invention includes at least one of the following beneficial technical effects:

1. by arranging the first-stage grinding box, the second-stage grinding box, the third-stage grinding box and the fourth-stage grinding box, the limestone powder can be ground to different degrees, so that the limestone powder with different particle sizes can be directly obtained, the operation that the limestone powder needs to be put into the grinding boxes again for processing is avoided, the working efficiency is effectively improved, and the product quality is ensured;

2. through setting up screening board and screening section of thick bamboo for the limestone powder of finer particle size and the limestone powder of coarser particle size alternate segregation to grind respectively the limestone powder and process, thereby obtain the limestone powder of different particle sizes, and then satisfy the different production requirements of enterprise.

Drawings

FIG. 1 is a schematic view showing a structure of a grinding machine in the prior art;

FIG. 2 is a schematic view of a limestone refining grinding apparatus according to an embodiment;

FIG. 3 is a cross-sectional view of a limestone refining mill in accordance with one embodiment;

FIG. 4 is a schematic structural view of a feed tank and a primary grinding tank in the example;

FIG. 5 is a schematic view showing the structure of a feed pipe and a classifying cylinder in the embodiment.

In the figure, 1, a grinder; 2. a box body; 21. a material conveying port; 22. a feed port; 23. a pressure roller; 24. a drive motor; 25. a transmission belt; 3. a feeding box; 31. a feed inlet; 32. a discharge port; 321. a primary discharge pipe; 33. a screening plate; 34. a side outlet; 35. a primary discharge pipe; 36. mounting a plate; 37. a rubber spring; 38. vibrating a motor; 4. a primary grinding box; 40. a support pillar; 41. a first-stage feeding pipe; 42. a primary discharge pipe; 421. a first valve; 43. a grinding roller; 44. a first motor; 45. a first-stage communicating pipe; 5. a secondary grinding box; 51. a second-stage discharge pipe; 52. a secondary branch pipe; 53. a second valve; 6. a delivery pipe; 61. a first feed delivery pipe; 611. a mounting ring; 62. a second delivery pipe; 63. a rotating shaft; 631. a plugging plate; 632. a second motor; 64. a helical blade; 65. a branch pipe; 651. a first branch pipe; 652. a second branch pipe; 66. a driven gear ring; 67. a driving gear; 671. a drive shaft; 672. a third motor; 68. a screening drum; 681. screening holes; 7. a third-stage grinding box; 71. a three-stage discharge pipe; 72. a third valve; 73. a third-level communicating pipe; 8. a four-stage grinding box; 81. a four-stage discharge pipe.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Referring to fig. 2, the limestone fine grinding device disclosed by the invention comprises a square feeding box 3, and referring to fig. 4, a feeding hole 31 is formed in the top end of the feeding box 3, a discharging hole 32 is formed in the bottom end of the feeding box 3, and the discharging hole 32 is communicated with a funnel-shaped primary discharging pipe 321. Elementary row material pipe 321 intercommunication has one-level to grind case 4, and the top of one-level grinding case 4 is equipped with one-level inlet pipe 41, and elementary row material pipe 321 is kept away from the one end of feed box 3 and is stretched into one-level inlet pipe 41 in, and the bottom of one-level grinding case 4 is equipped with one-level discharging pipe 42. A square screening plate 33 is obliquely arranged in the feeding box 3, a side outlet 34 is formed in the side wall of the feeding box 3, the side outlet 34 is communicated with a primary discharging pipe 35, and one side edge of the screening plate 33 is flush with one side of the side outlet 34 close to the discharging hole 32. The distance between one side edge of the screening plate 33 close to the side outlet 34 and the feed inlet 31 is larger than the distance between one side edge of the screening plate 33 far away from the side outlet 34 and the feed inlet 31, so that after the limestone fragments are fed, limestone powder with smaller particle size can fall into the primary grinding box 4 through the screening plate 33, and the screening plate 33 with larger particle size can be discharged into the primary discharge pipe 35.

Referring to fig. 4, two opposite side walls of the feeding box 3 are provided with two square mounting plates 36 close to the discharge port 32, the first-stage grinding box 4 is provided with four support columns 40, and the four support columns 40 correspond to the four mounting plates 36 one by one. The end of each support column 40 remote from the primary grinding box 4 is provided with a rubber spring 37, and the end of the rubber spring 37 remote from the support column 40 is connected to the mounting plate 36. The bottom of the feeding box 3 is provided with a vibration motor 38, and when the vibration motor 38 is started, the feeding box 3 can be driven to vibrate, so that the limestone screening by the screening plate 33 is accelerated.

Referring to fig. 4, the primary grinding tank 4 is provided with two parallel grinding rollers 43, both ends of the grinding rollers 43 are rotatably connected to the side walls of the primary grinding tank 4, respectively, and the limestone falling into the primary grinding tank 4 is ground by the grinding rollers 43. One end of the grinding roller 43 penetrates through the side wall of the primary grinding box 4, two opposite side walls of the primary grinding box 4 are provided with a first motor 44, and the first motor 44 is connected to the grinding roller 43 through a transmission belt 25 so as to drive the grinding roller 43 to rotate through the first motor 44.

Referring to fig. 2, the primary discharging pipe 35 is communicated with the secondary grinding box 5, a secondary discharging pipe 51 is arranged at the bottom end of the secondary grinding box 5, and a feeding pipe 6 is communicated with one end, far away from the secondary grinding box 5, of the secondary discharging pipe 51. Referring to fig. 5, a cylindrical rotating shaft 63 is provided in the feed delivery pipe 6 along the length direction of the feed delivery pipe 6, both ends of the rotating shaft 63 are rotatably connected to the feed delivery pipe 6, respectively, and helical blades 64 are provided on the outer peripheral side wall of the rotating shaft 63. Both ends of the feed delivery pipe 6 are provided with plugging plates 631 to plug the orifice of the feed delivery pipe 6. One end of the rotating shaft 63 close to the secondary discharging pipe 51 penetrates through the blocking plate 631 and is connected with a second motor 632, and the second motor 632 is started to drive the rotating shaft 63 to rotate, so that the helical blades 64 are used for pushing the limestone powder to move along the length direction of the feeding pipe 6.

Referring to fig. 5, a cylindrical hollow screening cylinder 68 is arranged in the feed delivery pipe 6, two hollow mounting rings 611 for mounting the screening cylinder 68 are arranged in the feed delivery pipe 6, the screening cylinder 68 penetrates through the mounting rings 611, the screening cylinder 68 is rotatably connected with the mounting rings 611, the rotating shaft 63 and the helical blades 64 are both positioned in the screening cylinder 68, and the feed delivery pipe 6 is provided with a branch pipe 65. The feed delivery pipe 6 comprises a first feed delivery pipe 61 and a second feed delivery pipe 62, the branch pipe 65 comprises a funnel-shaped first branch pipe 651 and a funnel-shaped second branch pipe 652, the first branch pipe 651 is communicated with the first feed delivery pipe 61, the second branch pipe 652 is communicated with the second feed delivery pipe 62, and one end of the screening cylinder 68 penetrates through the first feed delivery pipe 61 and extends into the second feed delivery pipe 62. The part of the screening cylinder 68 located in the first feed delivery pipe 61 is provided with a plurality of screening holes 681 along the radial direction of the screening cylinder 68. A driven gear ring 66 is sleeved on the screening cylinder 68, the driven gear ring 66 is located between the first conveying pipe 61 and the second conveying pipe 62, a driving gear 67 is meshed with the driven gear ring 66, a driving shaft 671 is coaxially arranged on the driving gear 67, a third motor 672 is arranged on the outer side wall of the first conveying pipe 61, and the driving end of the third motor 672 is connected to the driving shaft 671. The electric motor is started, the driving gear 67 can be driven to rotate, the driving gear 67 drives the driven gear ring 66 to rotate, the screening cylinder 68 is driven to rotate, screening of limestone powder by the screening cylinder 68 is accelerated, the limestone powder with smaller particle size falls into the first branch pipe 651 through the screening cylinder 68, and the limestone powder with larger particle size is pushed by the spiral blades 64 to be discharged into the second branch pipe 652.

Referring to fig. 3, the first branch pipe 651 is communicated with the tertiary grinding tank 7, the discharge end of the tertiary grinding tank 7 is communicated with a tertiary discharge pipe 71, and the tertiary discharge pipe 71 is provided with a third valve 72. The second branch pipe 652 is communicated with a four-stage grinding box 8, and the discharge end of the four-stage grinding box 8 is communicated with a four-stage discharge pipe 81. The same as the first-stage grinding box 4, two grinding rollers 43 parallel to each other are arranged in the second-stage grinding box 5, the third-stage grinding box 7 and the fourth-stage grinding box 8, and are connected with a first motor 44 through a transmission belt 25, and the first motor 44 is started to drive the grinding rollers 43 to rotate, so that limestone powder is ground.

Referring to fig. 3, the primary tapping pipe 42 is provided with a first valve 421. The secondary discharge pipe 51 is connected to a secondary branch pipe 52, the secondary discharge pipe 51 is provided with a second valve 53, and one end of the secondary branch pipe 52 connected to the secondary discharge pipe 51 is located between the second valve 53 and the secondary grinding tank 5. The secondary branch pipe 52 is also provided with a second valve 53. The first-stage discharge pipe 42 is provided with a first-stage communicating pipe 45, and one end of the first-stage communicating pipe 45, which is far away from the first-stage discharge pipe 42, is communicated with the third-stage discharge pipe 71 and the second-stage branch pipe 52 is communicated with the first-stage communicating pipe 45. The first communicating pipe 45 is also provided with a first valve 421 at one end close to the first discharging pipe 42. The third-level discharge pipe 71 is provided with a third valve 72, the third-level discharge pipe 71 is provided with a third communicating pipe 73 communicated with the fourth-level discharge pipe 81, and one end of the third communicating pipe 73 close to the third-level discharge pipe 71 is also provided with the third valve 72. By controlling the opening and closing of the first valve 421, the second valve 53 and the third valve 72, the discharging conditions of different grinding boxes can be flexibly adjusted, and the mixture of limestone powder with different particle sizes can be obtained, so that the method is better suitable for the production requirements of customers.

The implementation principle of the embodiment is as follows: after the limestone powder is put into the feeding box 3, the vibration motor 38 is started to drive the feeding box 3 to vibrate, so that the screening of the limestone powder by the screening plate 33 is accelerated, the limestone powder with smaller particle size falls into the first-stage grinding box 4, the limestone powder with larger particle size falls into the second-stage grinding box 5, and the limestone powder is ground and processed by the first-stage grinding box 4 and the second-stage grinding box 5 respectively, so that the limestone powder with different particle sizes is obtained.

The second motor 632 is started to move the limestone powder toward the second feed conveyor 62 by the action of the helical blade 64. The third motor 672 is started to drive the screening cylinder 68 to rotate, so that the screening of the screening cylinder 68 on the limestone powder is accelerated, the limestone powder with smaller particle size falls into the third-stage grinding box 7, the limestone powder with larger particle size falls into the fourth-stage grinding box 8, and the limestone is ground and processed by the third-stage grinding box 7 and the fourth-stage grinding box 8 respectively, so that the limestone powder with finer particle size is obtained.

In addition, by controlling the opening and closing of the first valve 421, the second valve 53 and the third valve 72, limestone powder with a single particle size or a mixture of limestone powders with different particle sizes can be obtained, so that the production requirements of enterprises can be better met, and the product quality is ensured.

Compared with the prior art, the limestone powder grinding device has the advantages that limestone powder with a single particle size or a mixture of limestone powder with different particle sizes can be directly obtained according to actual needs, the processing is convenient and rapid, the condition that the limestone powder needs to be put into the grinding box again to obtain the limestone powder with different particle sizes is avoided, the working efficiency is effectively improved, and the product quality is ensured.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.

Claims

1. A limestone refining grinding device comprises a primary grinding box (4), two grinding rollers (43) which are parallel to each other are arranged in the primary grinding box (4), a first motor (44) is arranged on the outer side wall of the primary grinding box (4), the driving end of the first motor (44) is connected with the grinding rollers (43) through a transmission belt (25), and the limestone refining grinding device is characterized in that: the limestone powder grinding device is characterized by further comprising a second-stage grinding box (5) and a feeding box (3), wherein the feeding box (3) is communicated with the first-stage grinding box (4) and the second-stage grinding box (5), and a screening plate (33) used for screening limestone powder with a smaller particle size to the first-stage grinding box (4) and conveying limestone powder with a larger particle size to the second-stage grinding box (5) is obliquely arranged in the feeding box (3).

2. The apparatus of claim 1, wherein said means for refining said limestone comprises: a primary discharging pipe (35) communicated with the feeding box (3) is arranged on the side wall of the feeding box (3), and one end, far away from the feeding box (3), of the primary discharging pipe (35) is communicated with the secondary grinding box (5);

a primary discharging pipe (321) communicated with the primary grinding box (4) is arranged at the bottom of the feeding box (3);

two opposite side walls of the feeding box (3) are respectively provided with a rubber spring (37), one end of each rubber spring (37) is connected to the side wall of the feeding box (3), and the other end of each rubber spring (37) is connected to the primary grinding box (4);

the feeding box also comprises a vibration component for driving the feeding box (3) to vibrate.

3. The apparatus for limestone-refining grinding of claim 2 wherein: the vibration component comprises a vibration motor (38) arranged at the bottom of the feeding box (3).

4. The apparatus of claim 1, wherein said means for refining said limestone comprises: the discharge end of the second-stage grinding box (5) is communicated with a third-stage grinding box (7) and a fourth-stage grinding box (8) through a conveying device, and the discharge end of the second-stage grinding box (5) is provided with a screening device which is used for screening limestone powder with a smaller particle size to the third-stage grinding box (7) and conveying limestone powder with a larger particle size to the fourth-stage grinding box (8).

5. The apparatus for limestone refining grinding of claim 4 wherein: the conveying device comprises a conveying pipe (6) communicated with the discharge end of the secondary grinding box (5), a rotating shaft (63) is arranged in the conveying pipe (6) along the length direction of the conveying pipe (6), spiral blades (64) are arranged on the peripheral side wall of the rotating shaft (63), and two ends of the rotating shaft (63) are respectively rotatably connected to two ends of the conveying pipe (6);

the device also comprises a driving piece for driving the rotating shaft (63) to rotate around the axis of the rotating shaft (63).

6. The apparatus for limestone refining grinding of claim 5 wherein: the driving piece comprises a second motor (632) arranged at one end of the material conveying pipe (6), a blocking plate (631) is arranged at one end, close to the secondary grinding box (5), of the material conveying pipe (6), and one end of the rotating shaft (63) penetrates through the blocking plate (631) and is connected to the driving end of the second motor (632);

and a branch pipe (65) communicated with the three-stage grinding box (7) and the four-stage grinding box (8) is arranged on the peripheral side wall of the conveying pipe (6).

7. The apparatus for limestone refining grinding of claim 6 wherein: the screening device comprises a screening cylinder (68) which is coaxial with the rotating shaft (63) and is positioned in the conveying pipe (6), and the rotating shaft (63) and the helical blade (64) are both positioned in the screening cylinder (68);

and a mounting ring (611) for mounting the screening cylinder (68) is arranged in the feed delivery pipe (6).

8. The apparatus for limestone refining grinding of claim 7 wherein: both ends of the screening cylinder (68) are rotatably connected with the mounting ring (611), the screening cylinder (68) is coaxially sleeved with a driven gear ring (66), the screening cylinder further comprises a driving gear (67) which is meshed with the driven gear ring (66), and the driving gear (67) is coaxially provided with a driving shaft (671);

and a third motor (672) is installed on the outer side wall of the conveying pipe (6), and the driving end of the third motor (672) is connected to the driving shaft (671).

9. The apparatus of claim 1, wherein said means for refining said limestone comprises: the first-stage grinding box (4) is communicated with a first-stage discharge pipe (42), the third-stage grinding box (7) is communicated with a third-stage discharge pipe (71), and the fourth-stage grinding box (8) is communicated with a fourth-stage discharge pipe;

one-level discharging pipe (42) are equipped with one-level communicating pipe (45) with tertiary discharging pipe (71) intercommunication, tertiary discharging pipe (71) are equipped with tertiary communicating pipe (73) with level four discharging pipe intercommunication, one-level discharging pipe (42) and one-level communicating pipe (45) all are equipped with first valve (421), tertiary discharging pipe (71) and tertiary communicating pipe (73) all are equipped with third valve (72).