阅读说明：本技术 一种具有不同研磨区的立磨研磨结构设计方法 (Design method of vertical mill grinding structure with different grinding areas ) 是由 豆海建 何小龙 唐清华 刘畅 秦景平 于涛 于 2021-07-20 设计创作，主要内容包括：本发明公开了一种具有不同研磨区的立磨研磨结构设计方法,立磨研磨结构包括磨盘和磨辊,上述磨辊设计为复合辊,具体结构如下：所述磨辊包括磨辊本体,磨辊本体上套装有辊套,形成胎锥复合辊；辊套的外表面由大径端向小径端包括凸出的曲线型胎辊段和锥辊段,磨盘上设有曲率半径与磨辊一致的沟槽,在沟槽内边缘向磨盘中心设有耐磨衬板；靠近挡料圈侧的耐磨衬板端部设有曲率半径与磨辊一致的曲面；上述磨辊的锥辊段和耐磨衬板、磨盘之间形成研磨区Ⅰ和研磨区Ⅱ,然后确立磨研磨结构的主要参数和计算。上述方案提高了研磨效率,降低了循环负荷；增加了物料脱离磨盘的难度,延长了物料停留在磨盘上的时间,使得物料研磨更加充分；胎锥复合辊的两个研磨区对粗颗粒和细颗粒具有针对性的破碎作用,应用在分级粉磨技术中能够发挥优异的效果。(The invention discloses a design method of a vertical mill grinding structure with different grinding areas, wherein the vertical mill grinding structure comprises a grinding disc and a grinding roller, the grinding roller is designed into a composite roller, and the structure is as follows: the grinding roller comprises a grinding roller body, and a roller sleeve is sleeved on the grinding roller body to form a tire cone composite roller; the outer surface of the roller sleeve comprises a convex curve type tire roller section and a conical roller section from a large diameter end to a small diameter end, a grinding disc is provided with a groove with the curvature radius consistent with that of the grinding roller, and the inner edge of the groove is provided with a wear-resistant lining plate towards the center of the grinding disc; the end part of the wear-resistant lining plate close to the material blocking ring side is provided with a curved surface with the curvature radius consistent with that of the grinding roller; a grinding area I and a grinding area II are formed among the conical roller section, the wear-resistant lining plate and the grinding disc of the grinding roller, and then main parameters and calculation of a grinding structure are determined. The scheme improves the grinding efficiency and reduces the cyclic load; the difficulty of separating the materials from the grinding disc is increased, the time of the materials staying on the grinding disc is prolonged, and the materials are ground more fully; the two grinding areas of the tire cone composite roller have targeted crushing effect on coarse particles and fine particles, and can play an excellent role when being applied to a grading grinding technology.)

1. A design method for a grinding structure of a vertical mill with different grinding areas is characterized in that the grinding structure of the vertical mill comprises a grinding disc and a grinding roller, the grinding roller is designed into a composite roller, and the structure is as follows: the grinding roller comprises a grinding roller body, wherein a roller sleeve is sleeved on the grinding roller body and connected through a fastener to form a tire cone composite roller; the roll sleeve is internally provided with a central hole which is attached to the outer surface of the grinding roll body, and the outer surface of the roll sleeve comprises a convex curve type tire roll section and a conical roll section from a large-diameter end to a small-diameter end; the grinding disc is provided with a wear-resistant lining plate, and the wear-resistant lining plate is divided into a groove with the curvature radius consistent with that of the grinding roller and a flat disc area from the inner edge of the groove to the center of the grinding disc; a grinding area I is formed between the conical roller section of the grinding roller and the flat disc area of the wear-resistant lining plate; a grinding area II is formed between the tyre roller section of the grinding roller and the groove of the grinding disc;

the design method of the vertical mill grinding structure comprises the following steps:

the main parameters of the abrasive structure are first established: the diameter D of the grinding disc and the number n of the grinding rollers; then the diameter D of the grinding roller is calculated in a distributed manner_RWidth of grinding roller B and width of groove disk D₁Width of tyre roller section B₁The curvature radius R of the tire roller; the specific determination and calculation is as follows:

1) number n of grinding rolls

The number of the grinding rollers can be selected to be n-2, 3 and 4 according to the difference of material characteristics and treatment capacity;

2) grinding roller angle alpha

The angle alpha of the grinding roller is 5-17 DEG

3) Diameter D of grinding roller_R

D_R＝0.5D～0.85D

4) Width B of grinding roller

B＝0.2D_R～0.4D_R

5) Width B of tyre roller section₁

B₁＝0.5B～0.8B

6) Radius of curvature R of tire roller

R＝0.7B₁～1.5B₁。

2. The design method of vertical mill grinding structure with different grinding zones as claimed in claim 1, characterized in that: the surface roughness of the matching surface of the central hole and the grinding roller body is less than or equal to 6.3.

3. The design method of vertical mill grinding structure with different grinding zones as claimed in claim 1, characterized in that: the grinding roller body is made of nodular cast iron QT400-18 or cast steel ZG20 SiMn.

4. The design method of vertical mill grinding structure with different grinding zones as claimed in claim 1, characterized in that: the roller sleeve is divided into a base layer base material and a wear-resistant layer, the base material is cast steel ZG20SiMn, the wear-resistant layer is a surfacing material, and the surfacing thickness is 40-60 mm; the hardness of the overlaying layer is 60 +/-5 HRC.

5. The design method of vertical mill grinding structure with different grinding zones as claimed in claim 1, characterized in that: the wear-resistant lining plate is divided into a base material and a wear-resistant layer, the base material is cast steel ZG20SiMn, the wear-resistant layer is a surfacing material, the surfacing thickness is 40-60 mm, and the hardness of the surfacing layer is 60 +/-5 HRC.

Technical Field

The invention belongs to the technical field of grinding, and particularly relates to a design method of a vertical mill grinding structure with different grinding areas.

Background

A vertical roller mill, called vertical mill for short, is a mill for grinding raw materials such as cement raw materials, cement clinker, slag, coal cinder and the like, and mainly comprises a mill body, a transmission device, a grinding disc and a grinding roller. When the grinder works, the motor drives the grinding disc to rotate through the speed reducer, materials fall in the center of the grinding disc from the feeding hole through the air locking feeder, and meanwhile hot air enters the grinder from the air inlet. The material moves to the edge of the grinding disc under the action of centrifugal force along with the rotation of the grinding disc, is sheared and crushed by the grinding roller when passing through a grinding area at the bottom of the grinding roller, the crushed material continuously moves to the edge of the grinding disc, a material blocking ring which passes over the edge of the grinding disc is taken up by the high-speed airflow of the air ring, coarse particles fall back to the grinding disc for re-grinding, fine particles upwards enter the powder concentrator along with the airflow, the coarse particles separated by the powder concentrator fall to the grinding disc for re-grinding, and qualified fine powder is discharged out of the grinding disc along with the airflow to form a product.

At present, the grinding zone structure adopted by the vertical mill mainly comprises: the device comprises a flat-disc conical roller, a flat-disc column roller, a groove disc tire roller, a sloping cam plate column roller and a sloping cam plate groove roller. The existing grinding area structure has the following defects when grinding materials: (1) the retention time of the materials in the grinding area is too short, the materials pass over the edge of the grinding disc without being fully ground, and the grinding is insufficient; (2) the material to be ground is divided into a powder concentrator return material and a new feed material, the new feed particles are relatively thick, the powder concentrator return material is relatively thin, the thick and thin particles are ground under the same grinding action, and the grinding efficiency is low.

To this end, the applicant has devised a method of designing a vertical mill polishing structure having different polishing zones that solves the above-mentioned problems.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a design method of a vertical mill grinding structure with different grinding areas.

The invention is realized in this way, a vertical mill grinding structure design method with different grinding areas, which is characterized in that the vertical mill grinding structure comprises a grinding disc and a grinding roller, the grinding roller is designed as a composite roller, and the specific structure is as follows: the grinding roller comprises a grinding roller body, wherein a roller sleeve is sleeved on the grinding roller body and connected through a fastener to form a tire cone composite roller; the roll sleeve is internally provided with a central hole which is attached to the outer surface of the grinding roll body, and the outer surface of the roll sleeve comprises a convex curve type tire roll section and a conical roll section from a large-diameter end to a small-diameter end; the grinding disc is provided with a wear-resistant lining plate, and the wear-resistant lining plate is divided into a groove with the curvature radius consistent with that of the grinding roller and a flat disc area (a horizontal straight section or a downward inclined straight section) from the inner edge of the groove to the center of the grinding disc; a grinding area I is formed between the conical roller section of the grinding roller and the flat disc area of the wear-resistant lining plate; a grinding area II is formed between the tyre roller section of the grinding roller and the groove of the grinding disc;

the design method of the vertical mill grinding structure comprises the following steps:

the main parameters of the abrasive structure are first established: the diameter D of the grinding disc and the number n of the grinding rollers; then the diameter D of the grinding roller is calculated in a distributed manner_RWidth of grinding roller B and width of groove disk D₁Width of tyre roller section B₁The curvature radius R of the tire roller; the specific determination and calculation is as follows:

1) number n of grinding rolls

The number of the grinding rollers can be selected to be n-2, 3 and 4 according to the difference of material characteristics and treatment capacity;

2) grinding roller angle alpha

The angle alpha of the grinding roller is 5-17 DEG

3) Diameter D of grinding roller_R

D_R＝0.5D～0.85D

4) Width B of grinding roller

B＝0.2D_R～0.4D_R

5) Width B of tyre roller section₁

B₁＝0.5B～0.8B

6) Radius of curvature R of tire roller

R＝0.7B₁～1.5B₁。

Preferably, the surface roughness of the matching surface of the central hole and the grinding roller body is less than or equal to 6.3.

Preferably, the grinding roller body material is nodular cast iron QT400-18 or cast steel ZG20 SiMn.

Preferably, the roller sleeve is divided into a base layer base material and a wear-resistant layer, the base material is cast steel ZG20SiMn, the wear-resistant layer is a surfacing material, and the surfacing thickness is 40-60 mm; the hardness of the overlaying layer is 60 +/-5 HRC.

Preferably, the wear-resistant lining plate is divided into a base material and a wear-resistant layer, the base material is cast steel ZG20SiMn, the wear-resistant layer is a surfacing material, the surfacing thickness is 40-60 mm, and the hardness of the surfacing layer is 60 +/-5 HRC.

The invention has the beneficial effects that: because the grinding structure formed by the tire cone composite grinding roller is adopted, the invention has the following advantages:

(1) two grinding areas with different stress forms are formed between the grinding disc and the grinding roller, the flat disc conical roller area mainly crushes materials through the extrusion action, thicker particles can be crushed quickly, and the groove disc tire roller area has the double functions of extrusion and shearing, so that the effective crushing of the thinner particles in the materials is facilitated. The comprehensive grinding effect of the two grinding areas improves the grinding efficiency and reduces the cyclic load;

(2) the structure of the groove disc tire roller area increases the difficulty of separating materials from the grinding disc, prolongs the time of the materials staying on the grinding disc and enables the materials to be ground more fully;

(3) the two grinding areas of the tire cone composite roller have targeted crushing effect on coarse particles and fine particles, and can play an excellent role when being applied to a grading grinding technology.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a graph of EDEM simulation calculations for the milling process;

FIG. 3 is a schematic diagram of the classification grinding principle of the present invention;

FIG. 4 is a grinding roll and disc process map;

FIG. 5 is a graph comparing EDEM simulation results for different polishing zone configurations under the same conditions;

FIG. 6 is a graph showing the variation of the mass of particles having a particle size of less than 2mm after grinding;

FIG. 7 is a graph showing the variation of the mass of particles having a particle size of less than 1mm after grinding;

FIG. 8 is a graph of the reduction ratio for different abrasive zone configurations;

FIG. 9 is a graph of power consumption of a host machine for different polishing configurations;

fig. 10 is a power consumption curve of the main machine for different grinding structures and grinding modes.

In the figure, 1, a grinding disc; 1-1, a groove; 1-2, wear-resistant lining boards; 2. grinding the roller; 2-1, grinding roller body; 2-2, roller sleeves; 2-20, central hole; 2-21, a tyre roller section; 2-22, conical roller sections; 3. a rocker arm; 4. a hydraulic cylinder; 5. a drive device; 6. a central feed pipe; 7. the powder concentrator returns a material feeding pipe.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Please refer to fig. 1 and fig. 2; a design method for a grinding structure of a vertical mill with different grinding areas is characterized in that the grinding structure of the vertical mill comprises a grinding disc 1 and a grinding roller 2, the grinding roller is designed into a composite roller, and the structure is as follows: the grinding roller comprises a grinding roller body 2-1, and a roller sleeve 2-2 is sleeved on the grinding roller body and connected through a fastener to form a tire cone composite roller; a central hole 2-20 which is attached to the outer surface of the grinding roller body is arranged in the roller sleeve, and the surface roughness of the matching surface of the central hole 2-20 and the grinding roller body is less than or equal to 6.3; the grinding roller body is made of nodular cast iron QT400-18 or cast steel ZG20 SiMn; the outer surface of the roller sleeve comprises a convex curve type tire roller section 2-21 and a conical roller section 2-22 from a large diameter end to a small diameter end; the roller sleeve comprises a base layer base material and a wear-resistant layer, the base material is cast steel ZG20SiMn, the wear-resistant layer is a surfacing material, the surfacing thickness is 40-60 mm, and the hardness of a surfacing layer (2-21 and 2-22) is 60 +/-5 HRC; the grinding disc 1 is provided with a wear-resistant lining plate, the wear-resistant lining plate is divided into a groove section with the curvature radius consistent with that of the grinding roller and a flat section 1-2 from the inner edge of the groove 1-1 to the center of the grinding disc, and the flat section can be a horizontal straight section; it can also be a straight section inclined downwards; the wear-resistant lining plate comprises a base layer base material and a wear-resistant layer, wherein the base material is nodular cast iron QT400-18 or cast steel ZG20SiMn, the wear-resistant layer is a surfacing material, the surfacing thickness is 40-60 mm, and the hardness of the surfacing layer is 60 +/-5 HRC.

A grinding area I is formed between the conical roller section of the grinding roller and the flat section of the lining plate; and a grinding area II is formed between the tyre roller section of the grinding roller and the groove of the grinding disc.

According to the working principle of the invention, a material to be ground is fed to the center of a wear-resistant lining plate 1 on a grinding disc, the grinding disc 1 and the wear-resistant lining plate 1 rotate under the action of a driving device 5, the material at the center of the wear-resistant lining plate 1 moves towards the edge of the grinding disc under the action of centrifugal force and firstly enters a grinding area I between a conical roller area 2B and a flat area 1B; in the grinding area I, the material is mainly crushed under the extrusion action, and coarse particles are more easily crushed under the extrusion action of the grinding area I; after the particles are crushed in the grinding area I, the particles continue to move towards the edge of the wear-resistant lining plate 1 to a grinding area II between the tire roller area 2A and the groove area 1A under the action of centrifugal force; in the grinding zone II, the material is crushed under the double action of extrusion and shearing. On the one hand, the shearing action in the grinding zone II is favorable for crushing fine particles, and on the other hand, the particles cross the groove zone 1A and need to overcome gravity besides the friction force, so that the retention time of the particles in the grinding zone II is prolonged, and the materials can be sufficiently ground. The grinding roller 1 is connected to a rocker arm 3, to which pressure is applied by means of a hydraulic cylinder 4.

Further, the tire cone composite roller has a more excellent effect when being applied to graded grinding because the tire cone composite roller has two grinding areas with different stress forms, and fig. 3 is a schematic diagram of a graded grinding principle. The working principle of applying the tire-cone composite roller to carry out graded grinding is as follows: the material to be ground is divided into returned material of the powder concentrator and new feed material, the returned material of the powder concentrator has relatively fine granularity, and the new feed material has relatively coarse granularity. The returned material of the powder concentrator is directly sent to the front of the tire roller section of the grinding roller through an independent returned material feeding pipe 7 of the powder concentrator, the fine particles are effectively ground by utilizing the shearing action of the tire roller area of the groove disk, the new material is still fed to the center of the grinding disk through the central feeding pipe 6, moves to the edge of the grinding disk under the action of centrifugal force and is sheared and crushed by the grinding roller when passing through the grinding area at the bottom of the grinding roller.

Based on the vertical grinding with different grinding areasThe design method of the grinding structure comprises the following steps of firstly, determining main parameters of the grinding structure: the diameter D of the grinding disc and the number n of the grinding rollers; then the diameter D of the grinding roller is calculated in a distributed manner_RWidth of grinding roller B and width of groove disk D₁Width of tyre roller section B₁The curvature radius R of the tire roller; the specific determination and calculation is as follows:

1) number n of grinding rolls

The number of the grinding rollers can be selected to be n-2, 3 and 4 according to the difference of material characteristics and treatment capacity;

2) grinding roller angle alpha

The angle alpha of the grinding roller is 5-17 DEG

3) Diameter D of grinding roller_R

D_R＝0.5D～0.85D

4) Width B of grinding roller

B＝0.2D_R～0.4D_R

5) Width B of tyre roller section₁

B₁＝0.5B～0.8B

6) Radius of curvature R of tire roller

R＝0.7B₁～1.5B₁。

By means of EDEM simulation, the traditional conical roller, the traditional tire cone composite roller A and the traditional tire cone composite roller B are calculated and researched, and the crushing effect simulation of 3 kinds of grinding rollers is shown in figure 5: wherein the curvature radius of the tread of the tire cone composite roller A is R80mm, the curvature radius of the tread of the tire cone composite roller B is R110mm, and the middle diameter D of the traditional cone roller_RMiddle diameter D of same-tire-cone composite roller_REqual, 458mm each.

In the simulation, the particle size of the material fed into the mill is set to be 5mm and 10mm, and for analyzing the grinding efficiency of different structures, the particles with the particle size less than 1mm and less than 2mm in the ground material are respectively counted to obtain the comparison curves shown in fig. 6 and 7. According to the curve, compared with a flat-disc conical roller, the material ground by the tire-cone composite roller has more particles with the particle sizes of less than 1mm and less than 2mm, and the increasing speed is higher, so that the grinding efficiency of the tire-cone composite roller is obviously higher than that of the flat-disc conical roller.

In order to compare the crushing efficiency of different grinding zone structures, the concept of the crushing ratio (the ratio of the mass of particles < 3.6mm in the ground material to the total mass of the particles) was defined, and the data were processed according to the calculation formula of the crushing ratio, and the results are shown in fig. 8 and table 1.

TABLE 1 crushing ratio of different grinding zone structures under the same conditions

	Mass of < 3.6mm granules (kg)	Total mass (kg)	Crushing ratio
				Tire cone composite roller A	0.605	1.105	0.548
Tire cone composite roller B	0.732	1.126	0.650
				Conical roller	0.327	1.269	0.258

As can be seen from the results of fig. 8 and table 1, the crushing ratio of the tread cone composite roll was larger than that of the flat-cone roll under the same conditions, regardless of the average crushing ratio or the crushing ratio with time.

In order to verify the actual effect of the tire-cone composite roller, tianjin institute has carried out grinding test research on the traditional cone roller, the tire-cone composite roller a and the tire-cone composite roller B by taking cement clinker as a raw material, and the test results are shown in fig. 9 and table 2.

Table 2 comparison of grinding effect of different grinding structures

As can be seen from fig. 9 and table 2: with a specific surface area of 3200cm²The power consumption of the tire cone composite roller is about 2.7kWh/t lower than that of a flat-disc cone roller, which is consistent with the result of EDEM simulation calculation.

Further, in order to verify the effect of the tire-cone composite roller for graded grinding, tianjin institute conducted grinding test research by using cement clinker as a raw material, and the test results are shown in fig. 10 and table 3.

TABLE 3 comparison of grinding effects of different grinding structures and grinding modes

As can be seen from fig. 10 and table 3: with a specific surface area of 3200cm²The power consumption of the stepped grinding of the tire-cone composite roller is reduced by 1.8-2.0 kWh/t and the amplitude is reduced by 10% compared with that of mixed grinding, and the power consumption of the tire-cone composite roller is reduced by about 2.7kWh/t and the amplitude is reduced by 10.8% compared with that of a flat-disc cone roller; compared with the traditional flat-disc conical roller mixed grinding, the stepped grinding of the tire-cone composite roller reduces the power consumption by 5.7kWh/t and the amplitude by 22.9 percent.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.