Ore grinding method and system

Abstract

The invention provides an ore grinding method and system.The method comprises the steps that raw ore is crushed till the particle size of-0.074 mm accounts for 20-25%, and coarse ore sand is obtained; the method comprises the following steps: blending coarse ore sand and water into first grinding ore pulp, adding the first grinding ore pulp and a first ore grinding medium into a ball mill, and carrying out first-order ore grinding to obtain first ore pulp of which the particle size is 0.074 mm and the proportion is 45-50%; grading and sorting the first ore pulp, blending the first ore pulp with water to obtain second ground ore pulp, carrying out rotational flow sorting, adding the second ground ore pulp and a second ore grinding medium into the ball mill, carrying out second-order ore grinding, carrying out rotational flow sorting on the obtained ore pulp to obtain qualified ore pulp with the particle size of-0.074 mm being greater than 70%, crushing the raw ore into coarse ore sand, and carrying out second-stage ore grinding to obtain qualified ore pulp, according to the method, the spherical segment-shaped special-shaped ore grinding medium is adopted, the over-grinding yield of products can be effectively reduced, the raw ore is crushed in a two-stage ore grinding mode, the raw ore can be effectively crushed into the qualified particle size, the method has the characteristic that the ore grinding process is easy to control, and the treatment capacity is larger by adopting the two-stage ore grinding mode.

Description

Technical Field

[0001] The present application relates to the field of ore grinding technology, and in particular to an ore grinding method and system. Background Art

[0002] Grinding operations are widely used in industries such as mineral processing, metallurgy, chemical engineering and power. Grinding operations reduce the particle size in the mill under the action of the collision between the medium (steel balls, steel bars, gravel, ceramic balls, etc.) and the material to be ground. The main task of grinding operations in the field of mineral processing is to produce grinding products of qualified sizes and to achieve sufficient dissociation of particles. The particle size composition distribution of the grinding products and the degree of dissociation of the grinding products will directly affect the selection effect and the economic benefits of the mineral processing plant; at the same time, the productivity of the mineral processing plant directly depends on the processing capacity of the grinding operation. The unreasonable grinding system is an important reason for the low production efficiency. Some existing factories mostly use a one-stage grinding method for grinding, but this method is difficult to control the grinding process and easily leads to low production efficiency. Therefore, it is necessary to develop a grinding method that can grind efficiently. Summary of the invention

[0003] The present application provides a grinding method and system, which can effectively crush the raw ore to solve the problems in the above-mentioned background technology.

[0004] The present application provides a grinding method, comprising the following steps: The raw ore is crushed to -0.074mm, accounting for 20-25%, to obtain coarse ore sand; The coarse ore sand and water are mixed into a first grinding slurry, and then added into a ball mill with a first grinding medium for first-stage grinding to obtain a first slurry with a -0.074 mm ratio of 45-50%; The first pulp is classified and sorted, and then mixed with water to form a second grinding pulp. After cyclone sorting, the second grinding medium is added to a ball mill for secondary grinding. The obtained pulp is further cyclone sorted to obtain a qualified pulp with a proportion of -0.074 mm greater than 70%; The shapes of the first grinding medium and the second grinding medium are both based on the spherical grinding medium, and are solid shapes obtained by cutting n equally spaced spherical segments of the same cross-section circle on the surface of the spherical grinding medium; When n is not 1, the center of each cross-sectional circle is distributed on the same circle with the center of the sphere as the center.

[0005] The grinding method provided in this application has the following beneficial effects: 1) The method of the present application uses a two-stage grinding method to crush the raw ore, which can effectively crush the raw ore to a qualified particle size. Compared with a single-stage grinding method, this can more effectively control the grinding process and avoid over-grinding of the ore. At the same time, the two-stage grinding method has a larger processing capacity.

[0006] 2) In the method of the present application, the particle size of the qualified slurry is controlled at -0.074 mm, accounting for more than 70%, which can fully crush the ore particles in the qualified slurry, effectively improve the dissociation rate of the ore, and is beneficial to the subsequent flotation process.

[0007] 3) In the present application, the grinding medium is a spherical-based special-shaped medium. This structure not only retains the original spherical point contact grinding of the grinding ball, but also increases the surface contact grinding ability of the medium through sectioning. Compared with the traditional spherical medium, this improves the adverse consequences of over-crushing caused by point contact grinding. Moreover, this surface contact crushing method can reduce over-crushing while making the particle size distribution of the obtained product more concentrated.

[0008] 4) 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 ore particles, thereby improving the efficiency of grinding.

[0009] 5) In the present application, the center of each cross-sectional circle is distributed on the same circumference with the center of the sphere as the center, so that the cross-sectional circles are distributed on the same circumference, which can fully ensure the rolling property of the grinding medium. And the two ends of the spherical surface separated by the separation zone formed by the cross-sectional circles retain the spherical structure of the original sphere, which can ensure the point contact grinding characteristics of the spherical surface of the grinding medium.

[0010] Optionally, the concentration of the first grinding slurry is 75-80%; The concentration of the second grinding slurry is 35~45%.

[0011] Optionally, the first grinding medium filling rate in the first-stage grinding process is 40-45%; The filling rate of the second grinding medium in the second-stage grinding process is 35~42%.

[0012] Optionally, the first grinding medium and the second grinding medium are made of one or more of chrome steel, manganese steel, and ceramic.

[0013] Optionally, 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; 1≤n≤8, and n is an integer.

[0014] Optionally, the addition 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; The addition system of the second grinding medium is m(Φ60, n=5)∶(Φ40, n=5)=1∶(3~3.5).

[0015] Optionally, the hardness of the first grinding medium is 60-63HRC; The hardness of the second grinding medium is 56~60HRC.

[0016] Optionally, the replenishment cycle 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; The replenishment cycle 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.

[0017] In a second aspect, the present application provides a grinding system, which is applied to any one of the grinding methods of the first aspect, comprising a first grinding mill, a spiral classifier, a first slurry pool, a cyclone, and a second grinding mill connected in series in sequence; The coarse material output end of the spiral classifier is also connected to the feed end of the first grinding mill; The first slurry pool is connected to the cyclone through a slurry pump; The cyclone is also connected to the magnetic separator and the qualified slurry pool in turn; The first slurry pool is also connected to the water replenishment tank; The water supply tank is also connected to the first grinding mill and the spiral classifier respectively; The second mill is also connected to the first pulp pool.

[0018] Optionally, the magnetic field strength of the magnetic separator is controlled to be 0.8~1.0T.

[0019] The grinding system provided in the present application can fully crush the feed ore to a qualified particle size for output through the coordinated use of the above-mentioned equipment, and the above-mentioned equipment cooperates closely with each other and has good processing efficiency. In addition, the above-mentioned grinding system has a simple operation process and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A schematic diagram of the three-dimensional structure of a grinding medium provided in one embodiment of the present application; Figure 2 A schematic diagram of a top view of a grinding medium provided in one embodiment of the present application; Figure 3 A schematic diagram of a grinding system provided in accordance with an embodiment of the present application.

[0022] Description of reference numerals: 1. First mill; 2. Spiral classifier; 3. First slurry pool; 4. Cyclone; 5. Second mill; 30. Make-up water tank; 31. Slurry pump; 41. Magnetic separator; 42. Qualified slurry pool. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0024] The present application provides a grinding method, comprising the following steps: The raw ore is crushed to -0.074mm, accounting for 20-25%, to obtain coarse ore sand; The coarse ore sand and water are mixed into a first grinding slurry, and then added into a ball mill with a first grinding medium for first-stage grinding to obtain a first slurry with a -0.074 mm ratio of 45-50%; The first pulp is classified and sorted, and then mixed with water to form a second grinding pulp. After cyclone sorting, the second grinding medium is added to a ball mill for secondary grinding. The obtained pulp is further cyclone sorted to obtain a qualified pulp with a proportion of -0.074 mm greater than 70%; The shapes of the first grinding medium and the second grinding medium are both based on the spherical grinding medium, and are solid shapes obtained by cutting n equally spaced spherical segments of the same cross-section circle on the surface of the spherical grinding medium; When n is not 1, the center of each cross-sectional circle is distributed on the same circle with the center of the sphere as the center.

[0025] The grinding method provided in this application has the following beneficial effects: 1) The method of the present application uses a two-stage grinding method to crush the raw ore, which can effectively crush the raw ore to a qualified particle size. Compared with a single-stage grinding method, this can more effectively control the grinding process and avoid over-grinding of the ore. At the same time, the two-stage grinding method has a larger processing capacity.

[0026] 2) In the method of the present application, the particle size of the qualified slurry is controlled at -0.074 mm, accounting for more than 70%, which can fully crush the ore particles in the qualified slurry, effectively improve the dissociation rate of the ore, and is beneficial to the subsequent flotation process.

[0027] 3) In the present application, the grinding medium is a spherical-based special-shaped medium. This structure not only retains the original spherical point contact grinding of the grinding ball, but also increases the surface contact grinding ability of the medium through sectioning. Compared with the traditional spherical medium, this improves the adverse consequences of over-crushing caused by point contact grinding. Moreover, this surface contact crushing method can reduce over-crushing while making the particle size distribution of the obtained product more concentrated.

[0028] 4) 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 ore particles, thereby improving the efficiency of grinding.

[0029] 5) In the present application, the center of each cross-sectional circle is distributed on the same circumference with the center of the sphere as the center, so that the cross-sectional circles are distributed on the same circumference, which can fully ensure the rolling property of the grinding medium. And the two ends of the spherical surface separated by the separation zone formed by the cross-sectional circles retain the spherical structure of the original sphere, which can ensure the point contact grinding characteristics of the spherical surface of the grinding medium.

[0030] Optionally, the concentration of the first grinding slurry is 75-80%; The concentration of the second grinding slurry is 35~45%.

[0031] In this application, the first-stage grinding is coarse grinding, the slurry concentration is high, that is, the liquid-solid ratio is low, the volume of solid phase contained in the slurry is also high, and the material hit by the steel balls is also high. At this time, a larger slurry concentration can effectively increase the processing capacity and also increase energy efficiency. The second-stage grinding is fine grinding, the slurry concentration is low, that is, the liquid-solid ratio is high, 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 used. While crushing the ore particles into finer particles, the contact between the ore particles and the grinding medium is relatively reduced, thereby reducing the occurrence of over-grinding.

[0032] Optionally, the first grinding medium filling rate in the first-stage grinding process is 40-45%; The filling rate of the second grinding medium in the second-stage grinding process is 35~42%.

[0033] In the present application, since the slurry concentration is high and the ore particles are coarse during the first-stage grinding process, a larger medium filling rate can be adopted to effectively crush the slurry. At the same time, it can also reduce the energy loss of the mining machine and improve energy efficiency.

[0034] Similarly, in the second-stage grinding process, the slurry concentration is low and the ore particles are fine, and a smaller media filling rate can effectively reduce the occurrence of over-grinding.

[0035] Optionally, the first grinding medium and the second grinding medium are made of one or more of chrome steel, manganese steel, and ceramic.

[0036] In this application, the grinding medium made of chrome steel, manganese steel and other materials has good strength and wear resistance, which can effectively reduce the wear of the grinding medium; ceramics are selected as the grinding medium, which has good hardness and light weight, and can reduce the specific gravity of the grinding medium, thereby reducing the power consumption of the mill operation.

[0037] Optionally, 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; Where 1≤n≤8, and n is an integer.

[0038] In this application Figure 1 and Figure 2 The schematic diagram of the structure of the grinding medium when n=4 is shown.

[0039] In the present application, 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. In actual use, when n increases, L should be reduced accordingly to ensure that there is enough space between two adjacent cross-sectional circles, so as to avoid the formation of sharp protrusions due to the small spacing between the two cross-sectional circles, which leads to the adverse consequence of easy wear of the grinding medium during the grinding process. Moreover, the above-mentioned design of the negative correlation between n and L can ensure the rolling property of the grinding medium while reducing the sharp edges and corners in the structure of the grinding medium.

[0040] Optionally, the addition 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; The addition system of the second grinding medium is m(Φ60, n=5)∶(Φ40, n=5)=1∶(3~3.5).

[0041] In the present application, the first-stage grinding is coarse grinding, and thus n=3 or 4 in the first grinding medium. This setting can retain more spherical structures, and through more point contact of spherical grinding, the original ore can be more effectively crushed during the coarse grinding process; similarly, the second-stage grinding is fine grinding, and when n=5, there are more surface contact and peeling grinding methods in the grinding medium. At this time, there are relatively fewer spherical surfaces, and at the same time, surface contact grinding, peeling grinding and other methods of plane grinding are added. The particle size of the product obtained by this surface contact grinding method is relatively concentrated, and can effectively reduce the over-grinding phenomenon caused by the point contact of the spherical surface during the grinding process.

[0042] Optionally, the hardness of the first grinding medium is 60-63HRC; The hardness of the second grinding medium is 56~60HRC.

[0043] In this application, within a certain range, the greater the hardness of the grinding medium, the easier it is to crush the ore, and the target ore can be crushed into finer particles. The hardness of the first grinding medium is 60~63HRC, which is higher than the hardness of the second grinding medium of 56~60HRC. This setting is because the coarse ore sand entering the first-stage grinding process has a larger particle size. If the hardness of the grinding medium is low, it is not conducive to crushing the coarse ore sand into a qualified particle size range. Secondly, due to the large particle size of the coarse ore sand, it is easy to cause the damage of the grinding medium during the first-stage grinding process, resulting in a large loss of the grinding medium. In the second-stage grinding, the ore sand needs to be crushed into a finer particle size. If a grinding medium with a relatively large hardness is used at this time, it is easy to cause over-grinding, which is not conducive to the production of qualified ore pulp. Therefore, the use of a grinding medium with a smaller hardness in the second-stage grinding can effectively avoid the occurrence of over-grinding.

[0044] Optionally, the replenishment cycle 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; The replenishment cycle 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.

[0045] In the present application, the grinding medium will gradually wear out during use. At this time, in order to ensure the distribution of qualified particle size of ore sand in the slurry, the grinding medium should be added in time. In the present application, the addition 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 addition system of the second grinding medium is m (Φ60, n=5): (Φ40, n=5) = 1: (3~3.5).

[0046] Second, as Figure 3 As shown, the present application provides a grinding system, which is applied to the grinding method of any one of the first aspects above, comprising a first grinding mill 1, a spiral classifier 2, a first slurry pool 3, a cyclone 4, and a second grinding 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 slurry pool 3 is connected to the cyclone 4 via a slurry pump 31; The cyclone 4 is also connected to the magnetic separator 41 and the qualified slurry pool 42 in sequence; The first slurry pool 3 is also connected to the water replenishment tank 30; The water supply tank 30 is also connected to the first grinding mill 1 and the spiral classifier 2 respectively; The second mill 5 is also connected to the first pulp pool 3 .

[0047] The grinding system provided in the present application can fully crush the feed ore to a qualified particle size for output through the coordinated use of the above-mentioned equipment, and the above-mentioned equipment cooperates closely with each other and has good processing efficiency. In addition, the above-mentioned grinding system has a simple operation process and is easy to implement.

[0048] Optionally, the magnetic field strength of the magnetic separator 41 is controlled to be 0.8-1.0T.

[0049] The magnetic separator 41 provided in the present application can remove magnetic impurities in the ore pulp to prevent them from interfering with the subsequent flotation process.

[0050] The use process of a grinding system is as follows: The crushed ore powder in the round ore bin is transported to the feeding conveyor belt through the electric vibrating feeder, and the ore enters the first mill 1 through the feeding conveyor belt for first-stage grinding; at the same time, a certain amount of water is added through the water tank 30 to adjust the concentration of the slurry to 75%-80%. This is to ensure the grinding concentration inside the ball mill on the one hand, and to make the slurry in the ball mill have a certain fluidity on the other hand, so that the slurry can be discharged from the ball mill outlet; the ground slurry enters the spiral classifier 2 along the chute, and the ball mill discharge concentration is about 75%-80%. The classifier can only The classification concentration can work normally only when it is between 45% and 55%. Therefore, a certain amount of supplementary water needs to be added to the spiral classifier 2 through the water tank 30 so that the slurry particles can settle freely. The coarser ore particles settle relatively quickly. After the rotation of the spiral classifier 2, the coarse ore particles enter the upper chute of the spiral classifier 2 to form the spiral classifier return sand and enter the first mill 1 for further grinding. The finer slurry is suspended in the upper layer of the settling area of ​​the spiral classifier 2 and overflows from the overflow weir as the slurry and supplementary water are continuously added. This part is called the classification overflow product. The classified overflow product is put into the first pulp pool 3, and a certain amount of water is added into it through the water tank 30 to adjust the concentration of the pulp to 35-45%. The pulp in the first pulp pool 3 is transferred to the cyclone 4 through the pulp pump 31, and is classified by the centrifugal effect of water. The pulp with qualified particle size is discharged from the overflow port, and the magnetic impurities in the pulp are removed by magnetic separation in the magnetic separator 41 to form the final product, that is, qualified pulp, and temporarily stored in the qualified pulp pool 42 for subsequent sorting operations. The unqualified pulp is sent to the second mill 5 for grinding, and the obtained pulp is transferred to the first pulp pool 3 for the next round of cyclone separation process.

[0051] In the present application, the beneficial effects of using the first grinding medium and the second grinding medium in the grinding system are as follows: 1) In the present application, the grinding medium is a spherical-based special-shaped medium. This structure retains the original spherical point contact grinding of the grinding ball and increases the surface contact grinding ability of the medium through sectioning. Compared with the traditional spherical medium, this improves the adverse consequences of over-crushing caused by point contact grinding. Moreover, this surface contact crushing method can reduce over-crushing while making the particle size distribution of the obtained product more concentrated.

[0052] 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 ore particles, thereby improving the efficiency of grinding.

[0053] 3) In the present application, the center of each cross-sectional circle is distributed on the same circumference with the center of the sphere as the center, so that the cross-sectional circles are distributed on the same circumference, which can fully ensure the rolling property of the grinding medium. And the two ends of the spherical surface separated by the separation zone formed by the cross-sectional circles retain the spherical structure of the original sphere, which can ensure the point contact grinding characteristics of the spherical surface of the grinding medium.

[0054] Experimental example Example 1 A grinding method is implemented by the following steps: S101, crush the raw ore to -0.074mm, accounting for 23%, to obtain coarse ore sand.

[0055] 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 together with the first grinding medium for first-stage grinding to obtain a first slurry with a -0.074 mm ratio of 45-50%. The first grinding medium addition system is m(Φ120, n=3):(Φ100, n=3):(Φ80, n=3):(Φ60, n=3)=1:1:1:1, and the first grinding medium filling rate is 40-45%.

[0056] S103, after grading and sorting the first slurry, mix it with water to form a second grinding slurry with a concentration of 40%, add it into a ball mill with the second grinding medium after cyclone sorting for secondary grinding, and then obtain the slurry after cyclone sorting to obtain a qualified slurry with a proportion of -0.074 mm 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%.

[0057] Example 2 A grinding method is implemented by the following steps: S201, crush the raw ore to -0.074mm, accounting for 20%, to obtain coarse ore sand.

[0058] 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 together with the first grinding medium for first-stage grinding to obtain a first slurry with a -0.074 mm ratio of 45-50%. 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 40%.

[0059] S203, after grading and sorting the first slurry, mix it with water to form a second grinding slurry with a concentration of 35-45%, add it and the second grinding medium into a ball mill for secondary grinding after cyclone sorting, and obtain the slurry after cyclone sorting to obtain a qualified slurry with a proportion of -0.074 mm 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%.

[0060] Example 3 A grinding method is implemented by the following steps: S301, crush the raw ore to -0.074mm, accounting for 25%, to obtain coarse ore sand.

[0061] 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 together with the first grinding medium for first-stage grinding to obtain a first slurry with a -0.074 mm ratio 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%.

[0062] S303, after grading and sorting the first slurry, mix it with water to form a second grinding slurry with a concentration of 45%, add it and the second grinding medium into a ball mill for secondary grinding after cyclone sorting, and then obtain the slurry after cyclone sorting to obtain a qualified slurry with a proportion of -0.074mm 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%.

[0063] Example 4 A grinding method is implemented by the following steps: S401, crush the raw ore to -0.074mm, accounting for 23%, to obtain coarse ore sand.

[0064] 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 together with the first grinding medium for first-stage grinding to obtain a first slurry with a -0.074 mm ratio 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%.

[0065] S403, after grading and sorting the first slurry, mix it with water to form a second grinding slurry with a concentration of 37%, add it and the second grinding medium into a ball mill for secondary grinding after cyclone sorting, and then obtain the slurry after cyclone sorting to obtain a qualified slurry with a proportion of -0.074 mm 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%.

[0066] In the above embodiments, the shapes of the first grinding medium and the second grinding medium are both based on the spherical grinding medium, and are solid shapes obtained by cutting out n equally spaced spherical segments of the same cross-sectional circle from its surface; 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.

[0067] 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.

[0068] Comparative Example 1 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.

[0069] Experimental example The experimental materials were selected from copper-molybdenum ore 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 and a proportion of 23%.

[0070] The experimental materials were subjected to product particle size composition analysis according to the qualified ore pulp obtained according to the above-mentioned Examples 1 to 4 and Comparative Example 1. The results are shown in Table 1.

[0071] Table 1 It can be seen from the results in Table 1 that the yield of the particle size less than 10 μm (i.e., the -10 μm particle size, which is used to indicate the over-grinding yield) in the qualified ore pulp obtained by the method of the present application is less than 7%, which is significantly lower than the result of 7.90% in Comparative Example 1. The higher the proportion of this particle size, the more serious the over-grinding of the material. Through the above comparison, this shows that the method of the present application can reduce the over-grinding yield.

[0072] In the results of Table 1, the yield of the particle size larger than 74 μm (i.e., the particle size of +74 μm, which is used to indicate the yield of the particle size that is not finely ground) is similar to the results of the embodiments and comparative example 1, but is less than the result of comparative example 1. This indicates that the grinding medium used in the scheme of the present application can crush the material with point contact of the spherical surface while having the pulverizing effect of plane contact, thus showing a better fine grinding ability than the complete ball milling effect.

[0073] 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 it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A grinding method, characterized in that: The steps include: The raw ore is crushed to -0.074mm, accounting for 20-25%, to obtain coarse ore sand; The coarse ore sand and water are mixed into a first grinding slurry, and then added into a ball mill with a first grinding medium for first-stage grinding to obtain a first slurry with a -0.074 mm ratio of 45-50%; The first pulp is classified and sorted, and then mixed with water to form a second grinding pulp. After cyclone sorting, the second grinding medium is added to a ball mill for secondary grinding. The obtained pulp is further cyclone sorted to obtain a qualified pulp with a proportion of -0.074 mm greater than 70%; The shapes of the first grinding medium and the second grinding medium are both based on the spherical grinding medium, and are solid shapes obtained by cutting n equally spaced spherical segments of the same cross-section circle on the surface of the spherical grinding medium; 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.

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

3. The grinding method according to claim 1, characterized in that: The filling rate of the first grinding medium in the first-stage grinding process is 40-45%; The filling rate of the second grinding medium in the second-stage grinding process is 35-42%.

4. The grinding method according to claim 1, characterized in that: The first grinding medium and the second grinding medium are made of one or more of chrome steel, manganese steel, and ceramic.

5. The grinding method according to claim 1, characterized in that: The distance L from the center of the cross-section circle to the center of the sphere is 0.85R≤L≤0.99R, where R is the radius of the sphere; 1≤n≤8, and n is an integer.

6. The grinding method according to claim 1, characterized in that: The addition 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; The addition system of the second grinding medium is m(Φ60, n=5)∶(Φ40, n=5)=1∶(3~3.5).

7. The grinding method according to claim 1, characterized in that: The hardness of the first grinding medium is 60~63HRC; The hardness of the second grinding medium is 56~60HRC.

8. The grinding method according to claim 1, characterized in that: The replenishment cycle 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; The replenishment cycle of the second grinding medium is to add 1.5 to 1.8 tons of the second grinding medium for every 22,000 to 25,000 tons of raw ore processed.

9. A grinding system, characterized in that: The grinding method applied to any one of claims 1 to 8, comprising a first grinding mill (1), a spiral classifier (2), a first slurry pool (3), a cyclone (4), and a second grinding 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 slurry pool (3) is connected to the cyclone (4) via a slurry pump (31); The cyclone (4) is also connected in sequence to the magnetic separator (41) and the qualified slurry pool (42); The first slurry pool (3) is also connected to a water replenishment tank (30); The water replenishment tank (30) is also connected to the first grinding mill (1) and the spiral classifier (2) respectively; The second mill (5) is also connected to the first pulp pool (3).

10. The grinding system according to claim 9, characterized in that: The magnetic field strength of the magnetic separator (41) is controlled to be 0.8-1.0T.

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