Grinding method and system

Abstract

The present application provides a grinding method and system. The method of the present application includes crushing the raw ore to a proportion of -0.074 mm accounting for 20-25% to obtain coarse ore sand; mixing the coarse ore sand and water to form a first grinding pulp, and then adding the first grinding medium and the first grinding pulp into a ball mill for first-stage grinding to obtain a first pulp with a proportion of -0.074 mm accounting for 45-50%; after classifying and separating the first pulp, mixing it with water to form a second grinding pulp, and after hydrocyclone separation, adding the second grinding medium and the second grinding pulp into a ball mill for second-stage grinding, and the obtained pulp is subjected to hydrocyclone separation again to obtain a qualified pulp with a proportion of -0.074 mm greater than 70%. After crushing the raw ore into coarse ore sand, two-stage grinding is carried out to obtain a qualified pulp. The method of the present application uses a special-shaped grinding medium in the shape of a spherical segment, which can effectively reduce the yield of over-ground products, and the two-stage grinding method is used to crush the raw ore, which can effectively crush the raw ore to a qualified particle size, has the characteristics of easy control in the grinding process, and has a larger processing capacity when using the two-stage grinding method.

Description

Technical Field

[0001] This application relates to the technical field of grinding, and particularly to a grinding method and system. Background Art

[0002] The grinding operation is widely used in industries such as mineral processing, metallurgy, chemical engineering, and power. Under the action of the collision between the medium (steel balls, steel rods, gravel, ceramic balls, etc.) and the material to be ground, the grinding operation reduces the particle size in the mill. In the field of mineral processing, the main tasks of the grinding operation are to produce grinding products with qualified sizes and to achieve sufficient dissociation of particles. The particle size composition distribution and the dissociation degree of the grinding products will directly affect the separation effect and the economic benefits of the concentrator; at the same time, the productivity of the concentrator directly depends on the processing capacity of the grinding operation. However, the unreasonable grinding system is an important reason for the low production efficiency. Some existing factories mostly use the method of single-stage grinding for grinding, but this method is not easy to control the grinding process and is extremely likely to lead to low production efficiency. Therefore, it is necessary to develop a grinding method that can grind efficiently. Summary of the Invention

[0003] This application provides a grinding method and system, which can effectively crush the raw ore to solve the problems in the above background art.

[0004] This application provides a grinding method, including the following steps:

[0005] Crush the raw ore to a proportion of -0.074 mm accounting for 20% - 25% to obtain coarse ore sand;

[0006] Mix the coarse ore sand and water to form a first grinding pulp, and then add it together with the first grinding medium into a ball mill for first-stage grinding to obtain a first pulp with a proportion of -0.074 mm accounting for 45% - 50%;

[0007] After classifying and separating the first pulp, mix it with water to form a second grinding pulp, and after hydrocyclone separation, add it together with the second grinding medium into a ball mill for second-stage grinding. The obtained pulp is then subjected to hydrocyclone separation again to obtain a qualified pulp with a proportion of -0.074 mm greater than 70%;

[0008] The shapes of the first grinding medium and the second grinding medium are both solid shapes obtained by cutting off n identical spherical segments with equal intervals on the surface of a spherical grinding medium as the basis;

[0009] When n is not 1, the centers of each cross-sectional circle are distributed on the same circumference with the center of the sphere as the center of the circle.

[0010] The grinding method provided by this application has the following beneficial effects:

[0011] 1) The method of this application uses two-stage grinding to crush the raw ore, which can effectively crush the raw ore to a qualified particle size. This can control the grinding process more effectively compared to single-stage grinding, avoid over-grinding of the ore, and at the same time, the two-stage grinding method has a larger throughput.

[0012] 2) In the method of this application, the particle size of the qualified pulp is controlled such that the proportion of -0.074mm is greater than 70%. This can fully crush the ore particles in the qualified pulp, effectively improve the dissociation rate of the ore, and is beneficial to the subsequent flotation process.

[0013] 3) In this application, the grinding medium is a special-shaped medium based on a sphere. This structure, while retaining the original spherical point-contact grinding of the grinding balls, also increases the surface-contact grinding ability of the medium through the cut surface. Compared with traditional spherical media, this improves the adverse consequences of over-crushing easily caused by point-contact grinding, and this surface-contact crushing method can reduce over-grinding while also making the particle size distribution of the obtained product more concentrated.

[0014] 4) In addition, since the grinding medium of this application is in the shape of a spherical segment obtained by cutting off a part of a sphere, under the same ball diameter, the mass of the grinding medium of this application is smaller, which can reduce the wear of the grinding medium on the inner lining of the mill and also reduce the energy loss of the mill; and when adding the same weight of grinding medium, the number of the grinding medium of this application is more, which is more conducive to crushing ore particles, thereby improving the grinding efficiency.

[0015] 5) In this application, the centers of each cross-sectional circle are distributed on the same circumference with the center of the sphere as the center. This will make the cross-sectional circles distributed on the same circumference, which can fully ensure the rolling property of the grinding medium. And at both ends of the spherical surface separated by the dividing belt formed by the cross-sectional circle on the spherical surface, the original spherical surface structure of the sphere is retained, which can ensure the point-contact grinding characteristics of the spherical surface of the grinding medium.

[0016] Optionally, the concentration of the first grinding pulp is 75 - 80%;

[0017] The concentration of the second grinding pulp is 35 - 45%.

[0018] Optionally, the filling rate of the first grinding medium in the first-stage grinding process is 40 - 45%;

[0019] The filling rate of the second grinding medium in the second-stage grinding process is 35 - 42%.

[0020] Optionally, the material of the first grinding medium and the second grinding medium is one or more of chrome steel, manganese steel, and ceramics.

[0021] Optionally, the distance L from the center of the cross-sectional circle to the center of the sphere takes a value of 0.85R ≤ L ≤ 0.99R, where R is the radius of the sphere;

[0022] 1 ≤ n ≤ 8, and n is an integer.

[0023] Optionally, the replenishment system of the first grinding medium is m(Φ120, n = 3 or 4)∶(Φ100, n = 3 or 4)∶(Φ80, n = 3 or 4)∶(Φ60, n = 3 or 4) = 1∶1∶1∶1;

[0024] The replenishment system of the second grinding medium is m(Φ60, n = 5)∶(Φ40, n = 5) = 1∶(3 - 3.5).

[0025] Optionally, the hardness of the first grinding medium is 60 - 63 HRC;

[0026] The hardness of the second grinding medium is 56 - 60 HRC.

[0027] Optionally, the replenishment period of the first grinding medium is to add 1.8 - 2.0 tons of the first grinding medium for every 2.0 - 2.5 ten thousand tons of raw ore processed;

[0028] The replenishment period of the second grinding medium is to add 1.5 - 1.8 tons of the second grinding medium for every 2.2 - 2.5 ten thousand tons of raw ore processed.

[0029] In a second aspect, the present application provides a grinding system, which is applied to the grinding method of any one of the above first aspects, and includes a first mill, a spiral classifier, a first pulp tank, a hydrocyclone, and a second mill connected in series in sequence;

[0030] The coarse material output end of the spiral classifier is also connected to the feed end of the first mill;

[0031] The first pulp tank is connected to the hydrocyclone through a pulp pump;

[0032] The hydrocyclone is also connected to a magnetic separator and a qualified pulp tank in sequence;

[0033] The first pulp tank is also connected to a water replenishment water tank;

[0034] The water replenishment water tank is also connected to the first mill and the spiral classifier respectively;

[0035] The second mill is also connected to the first pulp tank.

[0036] Optionally, the magnetic field intensity of the magnetic separator is controlled to be 0.8 - 1.0 T.

[0037] The grinding system provided by the present application, through the coordinated use of the above equipment, can fully crush the feed to a qualified particle size and output it. Moreover, the cooperation between the above equipment is close, and it has good processing efficiency. In addition, the above grinding system has a simple operation process and is easy to implement. Description of the Drawings

[0038] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 Schematic three-dimensional structure diagram of the grinding medium provided by an embodiment of the present application;

[0040] Figure 2 Schematic top view structure diagram of the grinding medium provided by an embodiment of the present application;

[0041] Figure 3 Schematic diagram of the grinding system provided by an embodiment of the present application.

[0042] Explanation of reference numerals:

[0043] 1. First mill; 2. Spiral classifier; 3. First pulp tank; 4. Hydrocyclone; 5. Second mill; 30. Make-up water tank; 31. Pulp pump; 41. Magnetic separator; 42. Qualified pulp tank. Specific implementation manners

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following clearly and completely describes the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts also belong to the scope of protection of the present application.

[0045] The present application provides a grinding method, including the following steps:

[0046] Crush the raw ore to a proportion of -0.074 mm accounting for 20 - 25% to obtain coarse ore sand;

[0047] Mix the coarse ore sand and water to form a first grinding pulp, and then add it together with the first grinding medium into a ball mill for first-stage grinding to obtain a first pulp with a proportion of -0.074 mm accounting for 45 - 50%;

[0048] After classifying and separating the first pulp, mix it with water to form a second grinding pulp. After hydrocyclone separation, add it together with the second grinding medium into a ball mill for second-stage grinding. The obtained pulp is then subjected to hydrocyclone separation to obtain a qualified pulp with a proportion of -0.074 mm greater than 70%;

[0049] The shapes of the first grinding medium and the second grinding medium are both solid shapes obtained by cutting off n identical sectional circles at equal intervals on the surface of a spherical grinding medium based on a sphere;

[0050] When n is not 1, the centers of each sectional circle are distributed on the same circumference with the center of the sphere as the center of the circle.

[0051] The grinding method provided by this application has the following beneficial effects:

[0052] 1) In the method of this application, the raw ore is crushed by means of two-stage grinding, which can effectively crush the raw ore to a qualified particle size. This can control the grinding process more effectively compared with single-stage grinding, avoid over-grinding of the ore, and at the same time, the two-stage grinding method has a larger throughput.

[0053] 2) In the method of this application, the particle size of the qualified pulp is controlled so that the proportion of -0.074mm is greater than 70%. This can fully crush the ore particles in the qualified pulp, effectively improve the dissociation rate of the ore, and is beneficial to the subsequent flotation process.

[0054] 3) In this application, the grinding medium is a special-shaped medium based on a sphere. This structure, while retaining the original spherical point-contact grinding of the grinding ball, also increases the surface-contact grinding ability of the medium through the cut surface. Compared with traditional spherical media, this improves the adverse consequences of over-crushing easily caused by point-contact grinding. Moreover, this surface-contact crushing method can reduce over-grinding while making the particle size distribution of the obtained product more concentrated.

[0055] 4) In addition, since the grinding medium of this application is in the shape of a spherical segment obtained by cutting off a part of a sphere, under the same ball diameter, the mass of the grinding medium of this application is smaller, which can reduce the wear of the grinding medium on the inner lining of the mill and also reduce the energy loss of the mill; and when adding the same weight of grinding medium, the number of the grinding medium of this application is more, which is more conducive to crushing ore particles, thereby improving the grinding efficiency.

[0056] 5) In this application, the centers of each sectional circle are distributed on the same circumference with the center of the sphere as the center of the circle, which will make the sectional circles distributed on the same circumference, and can fully ensure the rolling property of the grinding medium. And both ends of the spherical surface separated by the dividing belt formed by the sectional circle on the spherical surface retain the spherical surface structure of the original sphere, which can ensure the point-contact grinding characteristics of the spherical surface of the grinding medium.

[0057] Optionally, the concentration of the first grinding pulp is 75 - 80%;

[0058] The concentration of the second grinding pulp is 35 - 45%.

[0059] In this application, the first-stage grinding is rough grinding. When the pulp concentration is high, i.e., the liquid-solid ratio is small, the amount of solid phase contained in the volumetric pulp is also large, and more materials are hit by the steel balls. At this time, a larger pulp concentration can effectively increase the throughput and also improve the energy efficiency. The second-stage grinding is fine grinding. When the pulp concentration is low, i.e., the liquid-solid ratio is large, the effective specific gravity and activity of the grinding medium are enhanced, and the grinding effect is also enhanced. At this time, a lower grinding concentration is adopted. While crushing the ore particles to finer particles, since the contact between the ore particles and the grinding medium becomes relatively smaller, the phenomenon of over-grinding can be reduced.

[0060] Optionally, the filling rate of the first grinding medium during the first-stage grinding is 40 - 45%;

[0061] The filling rate of the second grinding medium during the second-stage grinding is 35 - 42%.

[0062] In this application, because the pulp concentration is high and the ore particles are coarse during the first-stage grinding, a larger filling rate of the medium can effectively crush the pulp. At the same time, it can also reduce the energy loss of the ore mill and improve the energy efficiency.

[0063] Similarly, during the second-stage grinding, the pulp concentration is low and the ore particles are fine. Using a smaller filling rate of the medium can effectively reduce the phenomenon of over-grinding.

[0064] Optionally, the material of the first grinding medium and the second grinding medium is one or more of chrome steel, manganese steel, and ceramics.

[0065] In this application, the grinding medium made of materials such as chrome steel and manganese steel has good strength and wear resistance, which can effectively reduce the wear of the grinding medium. Using ceramics as the grinding medium, it has good hardness and a relatively light mass, which can reduce the specific gravity of the grinding medium, thereby reducing the power consumption of the mill operation.

[0066] Optionally, the distance L from the center of the cross-sectional circle to the center of the sphere ranges from 0.85R ≤ L ≤ 0.99R, where R is the radius of the sphere;

[0067] where 1 ≤ n ≤ 8 and n is an integer.

[0068] In this application Figure 1 and Figure 2 shows the structural schematic diagram of the grinding medium when n = 4.

[0069] In this application, the distance L from the center of the cross-sectional circle to the center of the sphere ranges from 0.85R to 0.99R, where R is the radius of the sphere; 1 ≤ n ≤ 8 and n is an integer. In actual use, when n increases, L should be correspondingly reduced to ensure sufficient spacing between two adjacent cross-sectional circles and avoid the formation of sharp protrusions due to too small a spacing between the two cross-sectional circles, which may lead to easy wear of the grinding media during the grinding process. Moreover, the design of the negative correlation between n and L can reduce the sharp edges and corners in the structure of the grinding media while ensuring the rolling performance of the grinding media.

[0070] Optionally, the replenishment system of the first grinding media is m(Φ120, n = 3 or 4)∶(Φ100, n = 3 or 4)∶(Φ80, n = 3 or 4)∶(Φ60, n = 3 or 4)=1∶1∶1∶1;

[0071] The replenishment system of the second grinding media is m(Φ60, n = 5)∶(Φ40, n = 5)=1∶(3 - 3.5).

[0072] In this application, the first-stage grinding is coarse grinding, so n = 3 or 4 in the first grinding media. This setting can retain more spherical structures. Through the point contact method of spherical grinding in a relatively large number, the raw ore can be more effectively crushed during the coarse grinding process. Similarly, the second-stage grinding is fine grinding. When n = 5, there are more surface contact and peeling grinding methods in the grinding media, with relatively fewer spherical surfaces at this time. At the same time, the surface contact grinding methods such as grinding and peeling by surface contact in planar grinding are increased. The particle size of the products ground by this surface contact grinding method is relatively concentrated, and the over-grinding phenomenon caused by the point contact grinding of spherical surfaces can be effectively reduced.

[0073] Optionally, the hardness of the first grinding media is 60 - 63HRC;

[0074] The hardness of the second grinding media is 56 - 60HRC.

[0075] In this application, within a certain range, the greater the hardness of the grinding media, the easier it is to crush the ore and the finer the target ore can be crushed. The hardness of the first grinding media is 60 - 63HRC, which is higher than the hardness of the second grinding media of 56 - 60HRC. This setting is because the particle size of the coarse ore sand entering the first-stage grinding process is relatively large. If the hardness of the grinding media is too low, on the one hand, it is not conducive to crushing the coarse ore sand to the qualified particle size range, and on the other hand, due to the relatively large particle size of the coarse ore sand, the grinding media is easily damaged during the first-stage grinding process, resulting in a relatively large loss of the grinding media. When fine grinding in the second stage, the ore sand needs to be crushed to a finer particle size. If a grinding media with too large a hardness is used at this time, it is easy to cause over-grinding, which is not conducive to the production of qualified pulp. Therefore, using a grinding media with a smaller hardness in the second-stage grinding can effectively avoid the occurrence of over-grinding.

[0076] Optionally, the replenishment period of the first grinding medium is to add 1.8 - 2.0 tons of the first grinding medium for every 20,000 - 25,000 tons of raw ore processed;

[0077] The replenishment period of the second grinding medium is to add 1.5 - 1.8 tons of the second grinding medium for every 22,000 - 25,000 tons of raw ore processed.

[0078] In this application, during the use of the grinding medium, it will gradually wear. At this time, to ensure the qualified particle size distribution of the ore sand in the pulp, the grinding medium should be replenished in a timely manner. In this application, the replenishment system of the first grinding medium is as described above, that is, m(Φ120, n = 3 or 4)∶(Φ100, n = 3 or 4)∶(Φ80, n = 3 or 4)∶(Φ60, n = 3 or 4)=1∶1∶1∶1. Similarly, the replenishment system of the second grinding medium is m(Φ60, n = 5)∶(Φ40, n = 5)=1∶(3 - 3.5).

[0079] Second, as Figure 3 shown, this application provides a grinding system applied to the grinding method of any item in the first aspect above, including a first grinding mill 1, a spiral classifier 2, a first pulp tank 3, a hydrocyclone 4, and a second grinding mill 5 connected in series in sequence;

[0080] The coarse material output end of the spiral classifier 2 is also connected to the feed end of the first grinding mill 1;

[0081] The first pulp tank 3 is connected to the hydrocyclone 4 through a pulp pump 31;

[0082] The hydrocyclone 4 is also connected to a magnetic separator 41 and a qualified pulp tank 42 in sequence;

[0083] The first pulp tank 3 is also connected to a water replenishment water tank 30;

[0084] The water replenishment water tank 30 is also connected to the first grinding mill 1 and the spiral classifier 2 respectively;

[0085] The second grinding mill 5 is also connected to the first pulp tank 3.

[0086] The grinding system provided by this application can fully crush the feed to a qualified particle size and output it through the coordinated use of the above - mentioned equipment. Moreover, the cooperation between the above - mentioned equipment is close, with good processing efficiency. In addition, the above - mentioned grinding system has a simple operation process and is easy to implement.

[0087] Optionally, the magnetic field intensity of the magnetic separator 41 is controlled to be 0.8 - 1.0 T.

[0088] The magnetic separator 41 set in this application can remove magnetic impurities in the pulp, avoiding interference with the subsequent flotation process.

[0089] A grinding system has the following usage process:

[0090] The crushed ore powder in the round ore bin is conveyed to the feed conveyor belt through an electromagnetic vibrator feeder, and then the ore enters the first mill 1 through the feed conveyor belt for first-stage grinding; at the same time, a certain amount of water is added through the water replenishing tank 30 to adjust the concentration of the pulp to 75-80%. On the one hand, this is to ensure the grinding concentration inside the ball mill, and on the other hand, it is to make the pulp in the ball mill have a certain fluidity so that the pulp can flow out along the outlet of the ball mill; the ground pulp enters the spiral classifier 2 along the chute. The discharge concentration of the ball mill is about 75%-80%. The classifier can only work normally when the classification concentration is 45%-55%. Therefore, a certain amount of supplementary water needs to be added to the spiral classifier 2 through the water replenishing tank 30 so that the pulp particles can settle freely. The coarser ore particles settle relatively faster. After the coarse-grained ore rotates through the spiral classifier 2, it enters the upper chute of the spiral classifier 2 and forms the spiral classifier return sand and enters the first mill 1 again for further grinding. The finer pulp is suspended in the upper layer of the settling area of the spiral classifier 2 and overflows from the overflow weir as the pulp and supplementary water are continuously added. This part is called the classified overflow product. The classified overflow product enters the first pulp tank 3, and a certain amount of water is added to it through the water replenishing tank 30 to adjust the concentration of the pulp to 35-45%. The pulp in the first pulp tank 3 is transferred to the hydrocyclone 4 through the pulp pump 31 and classified by the centrifugal action of water. The pulp with qualified particle size is discharged from the overflow port, and after being magnetically separated by the magnetic separator 41 to remove the magnetic impurities in the pulp, the final product, that is, the qualified pulp, is formed and temporarily stored in the qualified pulp tank 42 and provided for subsequent separation operations. The unqualified pulp is sent to the second mill 5 for grinding, and the obtained pulp is transferred to the first pulp tank 3 for the next round of hydrocyclone separation process.

[0091] In this application, the beneficial effects of using the first grinding medium and the second grinding medium in the grinding system are as follows:

[0092] 1) In this application, the grinding medium is a special-shaped medium based on a sphere. This structure, while retaining the original spherical point-contact grinding of the grinding ball, also increases the surface-contact grinding ability of the medium through the cut surface. Compared with the traditional spherical medium, this improves the adverse consequence of easy over-grinding caused by point-contact grinding. Moreover, this surface-contact grinding method can make the particle size distribution of the obtained product more concentrated while reducing over-grinding.

[0093] 2) In addition, since the grinding medium of the present application is in the shape of a spherical segment obtained by cutting off a part of a sphere, the mass of the grinding medium of the present application is smaller under the same ball diameter, which can reduce the wear of the grinding medium on the mill lining and also reduce the energy loss of the mill; and when the same weight of grinding medium is added, the amount of grinding medium of the present application is greater, which is more conducive to crushing the mineral particles, thereby improving the efficiency of grinding.

[0094] 3) In this application, the centers of each cross-sectional circle are distributed on the same circumference, centered at the center of the sphere. This ensures that the cross-sectional circles are distributed on the same circumference, fully ensuring the rolling properties of the grinding media. Furthermore, the two ends of the sphere, separated by the dividing strip formed by the cross-sectional circles, retain the spherical structure of the original sphere, thus ensuring the point-contact grinding characteristics of the grinding media.

[0095] Experimental example

[0096] Example 1

[0097] A grinding method is implemented by the following steps:

[0098] S101, crush the raw ore to -0.074mm, accounting for 23%, to obtain coarse ore sand.

[0099] S102. Coarse ore sand and water are mixed into a first grinding slurry with a concentration of 78%, and then added into a ball mill for first-stage grinding with the first grinding medium to obtain a first slurry with a proportion of -0.074 mm of 45-50%. The addition system of the first grinding medium is m(Φ120, n=3):(Φ100, n=3):(Φ80, n=3):(Φ60, n=3)=1:1:1:1, and the filling rate of the first grinding medium is 40-45%.

[0100] S103. After grading and sorting the first slurry, mix it with water to form a second grinding slurry with a concentration of 40%. After cyclone sorting, add it and the second grinding medium into a ball mill for secondary grinding. The obtained slurry is further cyclone sorted to obtain a qualified slurry with a -0.074 mm ratio greater than 70%; the addition system of the second grinding medium is m (Φ60, n=5) : (Φ40, n=5) = 1:3.3, and the filling rate of the second grinding medium is 38%.

[0101] Example 2

[0102] A grinding method is implemented by the following steps:

[0103] S201. Crushing the raw ore to -0.074mm (20%) to obtain coarse ore sand.

[0104] S202. Coarse ore sand and water are mixed into a first grinding slurry with a concentration of 75%, and then added into a ball mill for first-stage grinding with the first grinding medium to obtain a first slurry with a proportion of 45-50% of -0.074 mm. The addition system of the first grinding medium is m(Φ120, n=4):(Φ100, n=4):(Φ80, n=4):(Φ60, n=4)=1:1:1:1, and the filling rate of the first grinding medium is 40%.

[0105] S203. After grading and sorting the first slurry, mix it with water to form a second grinding slurry with a concentration of 35-45%. After cyclone sorting, add it and the second grinding medium into a ball mill for secondary grinding. The obtained slurry is further cyclone sorted to obtain a qualified slurry with a -0.074 mm ratio greater than 70%. The addition system of the second grinding medium is m (Φ60, n=5): (Φ40, n=5) = 1:3, and the filling rate of the second grinding medium is 35%.

[0106] Example 3

[0107] A grinding method is implemented by the following steps:

[0108] S301, crush the raw ore to -0.074mm, accounting for 25%, to obtain coarse ore sand.

[0109] S302. Coarse ore sand and water are mixed into a first grinding slurry with a concentration of 80%, and then added into a ball mill for first-stage grinding with the first grinding medium to obtain a first slurry with a proportion of -0.074 mm of 50%. The addition system of the first grinding medium is m(Φ120, n=4):(Φ100, n=4):(Φ80, n=4):(Φ60, n=4)=1:1:1:1, and the filling rate of the first grinding medium is 45%.

[0110] S303. After grading and sorting the first slurry, mix it with water to form a second grinding slurry with a concentration of 45%. After cyclone sorting, add it and the second grinding medium into a ball mill for secondary grinding. The obtained slurry is further cyclone sorted to obtain a qualified slurry with a -0.074 mm ratio greater than 70%. The addition system of the second grinding medium is m (Φ60, n=5): (Φ40, n=5) = 1:3.5, and the filling rate of the second grinding medium is 42%.

[0111] Example 4

[0112] A grinding method is implemented by the following steps:

[0113] S401, crush the raw ore to -0.074mm, accounting for 23%, to obtain coarse ore sand.

[0114] S102. Coarse ore sand and water are mixed into a first grinding slurry with a concentration of 78%, and then added into a ball mill for first-stage grinding with the first grinding medium to obtain a first slurry with a proportion of -0.074 mm of 47%. The addition system of the first grinding medium is m(Φ120, n=4):(Φ100, n=4):(Φ80, n=4):(Φ60, n=4)=1:1:1:1, and the filling rate of the first grinding medium is 43%.

[0115] S403. After classification and sorting, the first slurry is mixed with water to form a second grinding slurry with a concentration of 37%. After cyclone sorting, the second grinding slurry and the second grinding medium are added to a ball mill for secondary grinding. The obtained slurry is further cyclone sorted to obtain a qualified slurry with a -0.074 mm ratio greater than 70%. The addition system of the second grinding medium is m (Φ60, n=5) : (Φ40, n=5) = 1 : (3.3), and the filling rate of the second grinding medium is 40%.

[0116] In the above embodiment, the shapes of the first grinding medium and the second grinding medium are both based on a spherical grinding medium, and are solid shapes obtained by cutting out n equally spaced spherical segments of the same cross-sectional circle from the surface of the spherical grinding medium; the distance L from the center of the cross-sectional circle to the center of the sphere is 0.85R≤L≤0.99R, where R is the radius of the sphere; wherein 1≤n≤8, and n is an integer; when n is not 1, the center of each cross-sectional circle is distributed on the same circumference with the center of the sphere as the center.

[0117] In the above embodiment, when n=3, the value of L is 0.90R; when n=4, the value of L is 0.92R; when n=5, the value of L is 0.95R.

[0118] Comparative Example 1

[0119] The remaining operations are the same as those in Example 4, except that grinding balls of the same size are used as the grinding media.

[0120] Experimental example

[0121] The experimental materials were copper-molybdenum ore from a certain place in Inner Mongolia. The ore was ground according to the methods provided in Examples 1 to 4 and Comparative Example 1. To ensure the uniformity of the raw materials, the feed amount for each group was 100 kg, and all of them came from the same batch of coarse ore sand with a particle size of -0.074 mm accounting for 23%.

[0122] The experimental materials were subjected to product particle size composition analysis according to the qualified ore pulp obtained in the above Examples 1 to 4 and Comparative Example 1. The results are shown in Table 1.

[0123] Table 1

[0124]

[0125] As can be seen from the results in Table 1, the yield of the qualified pulp obtained by the method of the present application with a particle size less than 10 μm (i.e., the -10 μm particle size, which is used to represent the yield of over-grinding) accounts for less than 7%, significantly lower than the result of 7.90% in Comparative Example 1. And the higher the proportion of this particle size, the more severely the material is over-ground. Through the above comparison, it shows that the method of the present application can reduce the yield of over-grinding.

[0126] In the results of Table 1, the yield of the particle size greater than 74 μm (i.e., the +74 μm particle size, which is used to represent the yield of under-grinding) in each example and Comparative Example 1 is similar but less than that in Comparative Example 1. This shows that the grinding medium adopted in the solution of the present application crushes the material by point contact on the spherical surface, and at the same time, it has the pulverizing effect of plane contact. Therefore, the fine grinding ability shows a better result compared with the complete ball milling effect.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A grinding method, characterized in that, It includes the following steps: Crush the raw ore to a proportion of -0.074mm accounting for 20 - 25% to obtain coarse ore sand; Mix the coarse ore sand and water to form a first grinding pulp, then add it together with the first grinding medium into a ball mill for first-stage grinding to obtain a first pulp with a proportion of -0.074mm accounting for 45 - 50%. The filling rate of the first grinding medium during the first-stage grinding is 40 - 45%; After classifying and separating the first pulp, mix it with water to form a second grinding pulp. After hydrocyclone separation, add it together with the second grinding medium into a ball mill for second-stage grinding. The obtained pulp is then hydrocyclone separated to obtain a qualified pulp with a proportion of -0.074mm greater than 70%. The filling rate of the second grinding medium during the second-stage grinding is 35 - 42%; The shapes of the first grinding medium and the second grinding medium are both solid shapes obtained by cutting off n identical spherical segments with equal intervals on the surface of a spherical grinding medium; When n is not 1, the centers of each cross-sectional circle are distributed on the same circumference with the center of the sphere as the center. The distance L from the center of the cross-sectional circle to the center of the sphere ranges from 0.85R ≤ L ≤ 0.99R, where R is the radius of the sphere; 1 ≤ n ≤ 8, and n is an integer; The replenishment system of the first grinding medium is m1∶m2∶m3∶m4 = 1∶1∶1∶1, where m1 is a spherical segment with Φ120 and n = 3 or 4; m2 is a spherical segment with Φ100 and n = 3 or 4; m3 is a spherical segment with Φ80 and n = 3 or 4; m4 is a spherical segment with Φ60 and n = 3 or 4. The replenishment system of the second grinding medium is m5∶m6 = 1∶(3 - 3.5), where m5 is a spherical segment with Φ60 and n = 5; m6 is a spherical segment with Φ40 and n = 5; The hardness of the first grinding medium is 60 - 63HRC; The hardness of the second grinding medium is 56 - 60HRC; The replenishment period of the first grinding medium is to add 1.8 - 2.0 tons of the first grinding medium for every 2.0 - 2.5 ten thousand tons of raw ore processed; the replenishment period of the second grinding medium is to add 1.5 - 1.8 tons of the second grinding medium for every 2.2 - 2.5 ten thousand tons of raw ore processed.

2. The grinding method according to claim 1, characterized in that, The concentration of the first grinding pulp is 75 - 80%; The concentration of the second grinding pulp is 35 - 45%.

3. The grinding method according to claim 1, wherein The materials of the first grinding medium and the second grinding medium are one or more of chrome steel, manganese steel, and ceramics.

4. A grinding system, characterized in that, Applied to the grinding method described in any one of claims 1 - 3 above, it includes a first mill (1), a spiral classifier (2), a first pulp tank (3), a hydrocyclone (4), and a second mill (5) connected in series in sequence; The coarse material output end of the spiral classifier (2) is also connected to the feed end of the first mill (1); The first pulp tank (3) is connected to the hydrocyclone (4) through a pulp pump (31); The hydrocyclone (4) is also connected to a magnetic separator (41) and a qualified pulp tank (42) in sequence; The first pulp tank (3) is also connected to a water replenishment tank (30); The water replenishment tank (30) is also connected to the first mill (1) and the spiral classifier (2) respectively; The second mill (5) is also connected to the first pulp tank (3).

5. The grinding system according to claim 4, wherein The magnetic field intensity of the magnetic separator (41) is controlled to be 0.8 to 1.0 T.

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