Ore grinding method for reducing excessive grinding and improving ore grinding efficiency of copper-nickel sulfide ore

Abstract

The invention discloses an ore grinding method for reducing excessive grinding and improving ore grinding efficiency of copper-nickel sulfide ore, which comprises the following steps: S1, carrying out primary ore grinding and two-time grading to realize primary closed-circuit ore grinding; s2, first-stage secondary ore grinding: settled sand graded by hydrocyclones X1 and X2 is fed into a first-stage secondary ball mill Q12 for ore grinding, discharged ore is fed into a pump pool B3, the concentration of ore pulp is adjusted to be 65%-68% in the pump pool in a water supplementing mode, the ore pulp is fed into a hydrocyclone group X3 for checking and grading, overflow of the hydrocyclone group X3 is fed into a coarse stirring tank and then enters a first-stage flotation process, and the overflow of the hydrocyclone group X3 enters a second-stage flotation process; settled sand is returned to the first-section secondary ball mill; s3, flotation middlings are reground; and S4, second-stage ore grinding is conducted, specifically, coarse-particle middlings in the step S3 are fed into a second-stage pump pool B5, graded through a second-stage cyclone set X4 and then fed into a second-stage coarse stirring tank in an overflowing mode, and then a second-stage flotation process is conducted.

Description

Technical Field

[0001] The invention relates to the technical field of ore dressing, and in particular to a grinding method for reducing over-grinding and improving grinding efficiency of copper-nickel sulfide ore. Background Art

[0002] As the mining depth of mining resources increases, the proportion of lean ores increases year by year, and the interpenetration relationship of various minerals in lean ores becomes more and more complex. The existing process flow can no longer meet production needs, and production capacity and technical indicators have reached bottlenecks. The original process is more difficult to adapt to the raw materials and recovery rate to complete the plan. It is urgent to transform the process flow of key equipment on site, improve the continuous production guarantee capability, achieve the matching of process flow with ore properties, and improve the recovery and utilization of useful metals.

[0003] Grinding is the last preparation process before ore selection. The purpose is to obtain a particle size product that fully dissociates useful minerals and gangue without over-grinding and meets the selection requirements. Taking the beneficiation process of a large copper-nickel sulfide ore as an example, a two-stage closed-circuit grinding method is adopted, which causes a large amount of over-grinding of the ore after grinding by the mill. The selection of minerals is easily limited by the particle size of the material. The mineral selection operation requires that the target minerals in the grinding product maintain a high monomer dissociation, and at the same time requires less coarse and fine particle size materials, and more intermediate easy-to-select particle size materials, that is, the floating material is required to maintain a uniform particle size. In the actual production process, the minerals that have been dissociated into monomers will continue to return to the grinding, resulting in serious over-grinding of the minerals. Because the existing flotation process structure cannot effectively select this part of the over-grinded fine-grained minerals, it affects the stable improvement of the copper-nickel grade and recovery rate, making it difficult to control the magnesium oxide in the concentrate, resulting in metal waste. In addition, because the flotation fine-grained minerals are returned to the grinding and classification process, the grinding machine time increases and the system processing capacity decreases; the energy consumption of the grinding system accounts for more than 70% of the total energy consumption of the concentrator, resulting in high costs for the grinding system. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a grinding method for copper-nickel sulfide ore which can reduce over-grinding and improve grinding efficiency.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows: A grinding method for reducing over-grinding and improving grinding efficiency of copper-nickel sulfide ore comprises the following steps: S1, one-stage grinding and two-stage classification, realizing one-stage closed-circuit grinding: copper-nickel sulfide minerals are transported to two first-stage ball mills Q11 by belt conveyors, and the pulp concentration is adjusted to 60%-65% by adding water. The discharged ore is fed to cyclones X1 and X2 respectively by sand pumps B1 and B2 for inspection and classification. The overflow of the first stage classification directly enters flotation, and after classification, the sedimentation and mixing enters the second stage ball mill Q12 and classification equipment X3 for further classification; S2, a second grinding: the sand after classification by the hydrocyclones X1 and X2 is fed to the second ball mill Q12 for grinding, and the discharge is fed to the pump pool B3, where the pulp concentration is adjusted to 65%-68% by adding water, and fed to the hydrocyclone group X3 for inspection and classification. The overflow of the hydrocyclone group X3 is fed to a rough stirring tank and then enters a flotation process, and the sand is returned to the second ball mill; S3, re-grinding of flotation ore: After the first flotation process, the coarse particles of ore enter the second grinding stage, and the fine particles of ore are directly transported to the second coarse stirring tank through the sand pump B4 and then undergo the second flotation process; S4, second-stage grinding: the coarse-grained medium ore in step S3 is fed into the second-stage pump pool B5, and after classification by the second-stage cyclone group X4, the overflow is fed into the second coarse stirring tank for the second-stage flotation process, and the sediment is fed into the second-stage ball mill Q2. The grinding slurry concentration is adjusted to 65%-68% by adding water, and the ball mill discharge is directly transported to the second coarse stirring tank through the pump pool B6 for the second-stage flotation process, thus realizing the second-stage open-circuit grinding operation.

[0006] Wherein, in the step S1, high chromium balls are added into the first stage ball mill, and the high chromium balls with a specification of Ø90 are used, and the filling rate is required to be 34%-38%.

[0007] Wherein, in the step S2, high chromium forging is added into a secondary ball mill, and the high chromium forging with a specification of Ø40×45 is used, and the filling rate is required to be 34%-37%.

[0008] Among them, in the steps S1 and S2, the size of the sand discharge nozzles of the cyclones X1 and X2 is 70 mm, and the size of the overflow pipe is 140 mm; the size of the sand discharge nozzle of the cyclone group X3 is 85 mm, and the size of the overflow pipe is 140 mm.

[0009] Wherein, in step S2, the feed pressure of the cyclone group X3 during operation is 0.08-0.11 MPa, the overflow concentration of the cyclone group X3 is 33%-39%, and the sand concentration thereof is 75%-80%.

[0010] The first stage of grinding is carried out through a closed circuit process to achieve differential grinding; the second stage of grinding adopts an open circuit grinding process.

[0011] Among them, in the step S4, ceramic balls are added into the second-stage ball mill, and nano-composite ceramic balls with specifications of Ø30 and Ø35 are used for grading, and the filling rate is required to be 40%-45%, and the grinding concentration is 65%-68%.

[0012] Among them, the sand discharge nozzle size of the second-stage cyclone group X4 is 70mm, the overflow pipe size is 140mm, the feed pressure of the second-stage cyclone group X4 during operation is 0.09-0.11Mpa, the overflow concentration of the cyclone group X4 is 24%-30%, and the sand concentration is 70%-80%.

[0013] Wherein, in step S2, the slurry concentration is adjusted to 66%-67% by adding water in the pump pool.

[0014] The beneficial effects of the present invention are as follows: the present invention classifies the first stage grinding twice, realizes the first stage closed-circuit grinding, improves the efficiency of the first stage secondary grinding, and at the same time directly transports the fine particles in the flotation ore to the second coarse stirring tank through a sand pump, and the coarse particles are transported to the second stage grinding for re-grinding through a sand pump, and implements the second stage open-circuit grinding, and re-grinds the fine-grained materials whose monomers are fully dissociated and meet the flotation feed particle size conditions, so as to avoid over-grinding caused by entering the mill. In addition, the new grinding medium combined with open-circuit grinding is also beneficial to improving the system processing capacity and reducing the grinding energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described below in conjunction with the accompanying drawings and embodiments: Figure 1 It is a process flow chart of the present invention; DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0017] Example 1 like Figure 1 As shown, a grinding method for copper-nickel sulfide ore to reduce over-grinding and improve grinding efficiency comprises the following steps: S1, one-stage grinding and two-stage classification, realizing one-stage closed-circuit grinding: copper-nickel sulfide minerals are transported to two first-stage ball mills Q11 by belt conveyors, and the pulp concentration is adjusted to 60% by adding water. The discharged ore is fed to cyclones X1 and X2 respectively by sand pumps B1 and B2 for inspection and classification. The overflow of the first stage classification directly enters flotation, and after classification, the sedimentation and mixing enters the second stage ball mill Q12 and classification equipment X3 for further classification; S2, a secondary grinding: the sand after classification by the hydrocyclones X1 and X2 is fed to the secondary ball mill Q12 for grinding, and the discharge is fed to the pump pool B3, where the pulp concentration is adjusted to 65% by adding water, and fed to the hydrocyclone group X3 for inspection and classification. The overflow of the hydrocyclone group X3 is fed to a rough stirring tank and then enters a flotation process, and the sand is returned to the secondary ball mill; S3, re-grinding of flotation ore: After the first flotation process, the coarse particles of ore enter the second grinding stage, and the fine particles of ore are directly transported to the second coarse stirring tank through the sand pump B4 and then undergo the second flotation process; S4, second-stage grinding: the coarse-grained medium ore in step S3 is fed into the second-stage pump pool B5, and after classification by the second-stage cyclone group X4, the overflow is fed into the second coarse stirring tank for the second-stage flotation process, and the sediment is fed into the second-stage ball mill Q2. The grinding slurry concentration is adjusted to 65% by adding water, and the ball mill discharge is directly transported to the second coarse stirring tank through the pump pool B6 for the second-stage flotation process, thus realizing the second-stage open-circuit grinding operation.

[0018] Wherein, in the step S1, high chromium balls with a specification of Ø90 are added into the first stage ball mill, and the filling rate is required to be 34%.

[0019] Wherein, in the step S2, high chromium forging is added into a secondary ball mill, and the high chromium forging with a specification of Ø40×45 is used, and the filling rate is required to be 34%.

[0020] Among them, in the steps S1 and S2, the size of the sand discharge nozzles of the cyclones X1 and X2 is 70 mm, and the size of the overflow pipe is 140 mm; the size of the sand discharge nozzle of the cyclone group X3 is 85 mm, and the size of the overflow pipe is 140 mm.

[0021] Wherein, in the step S2, the feed pressure of the cyclone group X3 during operation is 0.08 MPa, the overflow concentration of the cyclone group X3 is 33%, and the sand concentration thereof is 75%.

[0022] The first stage of grinding is carried out through a closed circuit process to achieve differential grinding; the second stage of grinding adopts an open circuit grinding process.

[0023] Among them, in the step S4, ceramic balls are added into the second-stage ball mill, and nano-composite ceramic balls with specifications of Ø30 and Ø35 are used for grading, and the filling rate is required to be 40% and the grinding concentration is 65%.

[0024] Among them, the sand discharge nozzle size of the second-stage cyclone group X4 is 70mm, the overflow pipe size is 140mm, the feed pressure of the second-stage cyclone group X4 when working is 0.09Mpa, the overflow concentration of the cyclone group X4 is 24%, and the sand concentration is 70%.

[0025] Example 2 like Figure 1 As shown, a grinding method for copper-nickel sulfide ore to reduce over-grinding and improve grinding efficiency comprises the following steps: S1, one-stage grinding and two-stage classification, realizing one-stage closed-circuit grinding: copper-nickel sulfide minerals are transported to two first-stage ball mills Q11 by belt conveyors, and the pulp concentration is adjusted to 65% by adding water. The discharged ore is fed to cyclones X1 and X2 respectively by sand pumps B1 and B2 for inspection and classification. The overflow of the first stage classification directly enters flotation, and after classification, the sedimentation and mixing enters the second stage ball mill Q12 and classification equipment X3 for further classification; S2, a secondary grinding: the sand after classification by the hydrocyclones X1 and X2 is fed to the secondary ball mill Q12 for grinding, and the discharge is fed to the pump pool B3, where the pulp concentration is adjusted to 68% by adding water, and fed to the hydrocyclone group X3 for inspection and classification. The overflow of the hydrocyclone group X3 is fed to a rough stirring tank and then enters a flotation process, and the sand is returned to the secondary ball mill; S3, re-grinding of flotation ore: After the first flotation process, the coarse particles of ore enter the second grinding stage, and the fine particles of ore are directly transported to the second coarse stirring tank through the sand pump B4 and then undergo the second flotation process; S4, second-stage grinding: the coarse-grained medium ore in step S3 is fed into the second-stage pump pool B5, and after classification by the second-stage cyclone group X4, the overflow is fed into the second coarse stirring tank for the second-stage flotation process, and the sediment is fed into the second-stage ball mill Q2. The grinding slurry concentration is adjusted to 68% by adding water, and the ball mill discharge is directly transported to the second coarse stirring tank through the pump pool B6 for the second-stage flotation process, thus realizing the second-stage open-circuit grinding operation.

[0026] Wherein, in the step S1, high chromium balls are added into the first stage ball mill, and the high chromium balls with a specification of Ø90 are used, and the filling rate is required to be 38%.

[0027] Wherein, in the step S2, high chromium forging is added into a secondary ball mill, and the high chromium forging with a specification of Ø40×45 is used, and the filling rate is required to be 37%.

[0028] Among them, in the steps S1 and S2, the size of the sand discharge nozzles of the cyclones X1 and X2 is 70 mm, and the size of the overflow pipe is 140 mm; the size of the sand discharge nozzle of the cyclone group X3 is 85 mm, and the size of the overflow pipe is 140 mm.

[0029] Wherein, in step S2, the feed pressure of the cyclone group X3 during operation is 0.11 MPa, the overflow concentration of the cyclone group X3 is 39%, and the sand concentration thereof is 80%.

[0030] The first stage of grinding is carried out through a closed circuit process to achieve differential grinding; the second stage of grinding adopts an open circuit grinding process.

[0031] Among them, in the step S4, ceramic balls are added into the second-stage ball mill, and nano-composite ceramic balls with specifications of Ø30 and Ø35 are used for grading, and the filling rate is required to be 45% and the grinding concentration is 68%.

[0032] Among them, the sand discharge nozzle size of the second-stage cyclone group X4 is 70mm, the overflow pipe size is 140mm, the feed pressure of the second-stage cyclone group X4 when working is 0.11Mpa, the overflow concentration of the cyclone group X4 is 30%, and the sand concentration is 80%.

[0033] Example 3 like Figure 1 As shown, a grinding method for copper-nickel sulfide ore to reduce over-grinding and improve grinding efficiency comprises the following steps: S1, one-stage grinding and two-stage classification, realizing one-stage closed-circuit grinding: copper-nickel sulfide minerals are transported to two first-stage ball mills Q11 by belt conveyors, and the pulp concentration is adjusted to 60% by adding water. The discharged ore is fed to cyclones X1 and X2 respectively by sand pumps B1 and B2 for inspection and classification. The overflow of the first stage classification directly enters flotation, and after classification, the sedimentation and mixing enters the second stage ball mill Q12 and classification equipment X3 for further classification; S2, a secondary grinding: the sand after classification by the hydrocyclones X1 and X2 is fed to the secondary ball mill Q12 for grinding, and the discharge is fed to the pump pool B3, in which the pulp concentration is adjusted to 66% by adding water, and fed to the hydrocyclone group X3 for inspection and classification. The overflow of the hydrocyclone group X3 is fed to a rough stirring tank and then enters a flotation process, and the sand is returned to the secondary ball mill; S3, re-grinding of flotation ore: After the first flotation process, the coarse particles of ore enter the second grinding stage, and the fine particles of ore are directly transported to the second coarse stirring tank through the sand pump B4 and then undergo the second flotation process; S4, second-stage grinding: the coarse-grained medium ore in step S3 is fed into the second-stage pump pool B5, and after classification by the second-stage cyclone group X4, the overflow is fed into the second coarse stirring tank for the second-stage flotation process, and the sediment is fed into the second-stage ball mill Q2. The grinding slurry concentration is adjusted to 65% by adding water, and the ball mill discharge is directly transported to the second coarse stirring tank through the pump pool B6 for the second-stage flotation process, thus realizing the second-stage open-circuit grinding operation.

[0034] Wherein, in the step S1, high chromium balls with a specification of Ø90 are added into the first stage ball mill, and the filling rate is required to be 34%.

[0035] Wherein, in the step S2, high chromium forging is added into a secondary ball mill, and the high chromium forging with a specification of Ø40×45 is used, and the filling rate is required to be 34%.

[0036] Among them, in the steps S1 and S2, the size of the sand discharge nozzles of the cyclones X1 and X2 is 70 mm, and the size of the overflow pipe is 140 mm; the size of the sand discharge nozzle of the cyclone group X3 is 85 mm, and the size of the overflow pipe is 140 mm.

[0037] Wherein, in the step S2, the feed pressure of the cyclone group X3 during operation is 0.08 MPa, the overflow concentration of the cyclone group X3 is 33%, and the sand concentration thereof is 75%.

[0038] The first stage of grinding is carried out through a closed circuit process to achieve differential grinding; the second stage of grinding adopts an open circuit grinding process.

[0039] Among them, in the step S4, ceramic balls are added into the second-stage ball mill, and nano-composite ceramic balls with specifications of Ø30 and Ø35 are used for grading, and the filling rate is required to be 40% and the grinding concentration is 65%.

[0040] Among them, the sand discharge nozzle size of the second-stage cyclone group X4 is 70mm, the overflow pipe size is 140mm, the feed pressure of the second-stage cyclone group X4 when working is 0.09Mpa, the overflow concentration of the cyclone group X4 is 24%, and the sand concentration is 70%.

[0041] Example 4 like Figure 1 As shown, a grinding method for copper-nickel sulfide ore to reduce over-grinding and improve grinding efficiency comprises the following steps: S1, one-stage grinding and two-stage classification, realizing one-stage closed-circuit grinding: copper-nickel sulfide minerals are transported to two first-stage ball mills Q11 by belt conveyors, and the pulp concentration is adjusted to 65% by adding water. The discharged ore is fed to cyclones X1 and X2 respectively by sand pumps B1 and B2 for inspection and classification. The overflow of the first stage classification directly enters flotation, and after classification, the sedimentation and mixing enters the second stage ball mill Q12 and classification equipment X3 for further classification; S2, a secondary grinding: the sand after classification by the hydrocyclones X1 and X2 is fed to the secondary ball mill Q12 for grinding, and the discharge is fed to the pump pool B3, where the pulp concentration is adjusted to 67% by adding water, and fed to the hydrocyclone group X3 for inspection and classification. The overflow of the hydrocyclone group X3 is fed to a rough stirring tank and then enters a flotation process, and the sand is returned to the secondary ball mill; S3, re-grinding of flotation ore: After the first flotation process, the coarse particles of ore enter the second grinding stage, and the fine particles of ore are directly transported to the second coarse stirring tank through the sand pump B4 and then undergo the second flotation process; S4, second-stage grinding: the coarse-grained medium ore in step S3 is fed into the second-stage pump pool B5, and after classification by the second-stage cyclone group X4, the overflow is fed into the second coarse stirring tank for the second-stage flotation process, and the sediment is fed into the second-stage ball mill Q2. The grinding slurry concentration is adjusted to 68% by adding water, and the ball mill discharge is directly transported to the second coarse stirring tank through the pump pool B6 for the second-stage flotation process, thus realizing the second-stage open-circuit grinding operation.

[0042] Wherein, in the step S1, high chromium balls are added into the first stage ball mill, and the high chromium balls with a specification of Ø90 are used, and the filling rate is required to be 38%.

[0043] Wherein, in the step S2, high chromium forging is added into a secondary ball mill, and the high chromium forging with a specification of Ø40×45 is used, and the filling rate is required to be 37%.

[0044] Among them, in the steps S1 and S2, the size of the sand discharge nozzles of the cyclones X1 and X2 is 70 mm, and the size of the overflow pipe is 140 mm; the size of the sand discharge nozzle of the cyclone group X3 is 85 mm, and the size of the overflow pipe is 140 mm.

[0045] Wherein, in step S2, the feed pressure of the cyclone group X3 during operation is 0.11 MPa, the overflow concentration of the cyclone group X3 is 39%, and the sand concentration thereof is 80%.

[0046] The first stage of grinding is carried out through a closed circuit process to achieve differential grinding; the second stage of grinding adopts an open circuit grinding process.

[0047] Among them, in the step S4, ceramic balls are added into the second-stage ball mill, and nano-composite ceramic balls with specifications of Ø30 and Ø35 are used for grading, and the filling rate is required to be 45% and the grinding concentration is 68%.

[0048] Among them, the sand discharge nozzle size of the second-stage cyclone group X4 is 70mm, the overflow pipe size is 140mm, the feed pressure of the second-stage cyclone group X4 when working is 0.11Mpa, the overflow concentration of the cyclone group X4 is 30%, and the sand concentration is 80%.

[0049] Among them, in Examples 3 and 4, the daily ore processing capacity of the two one-stage ball mill systems was increased from 3000t / d to 3250t / d, the one-stage grinding had two classification processes, and high chromium balls were selected as grinding media, which effectively reduced the proportion of materials below -10μm (over-grinded part) in the first-stage grinding product by 8.77%, the second stage used open-circuit grinding, and after matching with new grinding media ceramic balls, the proportion of materials below -10μm (over-grinded part) in the second-stage grinding product was reduced by 28%, the second stage used open-circuit grinding, the power consumption was reduced from 2.1kwh / t to 1.47kwh / t, the reduction was 53.25%, the cyclone group classification efficiency was increased by 21.11%, the classification quality efficiency was increased by 20.56%, the classification return sand ratio was reduced by 35.88%, the one-stage closed-circuit grinding and the grinding circuit secondary classification process improved the grinding efficiency, increased the grinding fineness, reduced the over-crushing of the grinding product, and made the grinding product particle size distribution more reasonable. The second-stage grinding effectively reduces the over-grinding problem of ore in the original process by directly flotating the fine particles in the flotation ore and open-circuit grinding the coarse particles.

[0050] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A method for grinding copper-nickel sulfide ore to reduce over-grinding and improve grinding efficiency, characterized in that: The following steps are involved: S1, one-stage grinding and two-stage classification, realizing one-stage closed-circuit grinding: copper-nickel sulfide minerals are transported to two first-stage ball mills Q11 by belt conveyors, and the pulp concentration is adjusted to 60%-65% by adding water. The discharged ore is fed to cyclones X1 and X2 respectively by sand pumps B1 and B2 for inspection and classification. The overflow of the first stage classification directly enters flotation, and after classification, the sedimentation and mixing enters the second stage ball mill Q12 and classification equipment X3 for further classification; S2, a second grinding: the sand after classification by the hydrocyclones X1 and X2 is fed to the second ball mill Q12 for grinding, and the discharge is fed to the pump pool B3, where the pulp concentration is adjusted to 65%-68% by adding water, and fed to the hydrocyclone group X3 for inspection and classification. The overflow of the hydrocyclone group X3 is fed to a rough stirring tank and then enters a flotation process, and the sand is returned to the second ball mill; S3, re-grinding of flotation ore: After the first flotation process, the coarse particles of ore enter the second grinding stage, and the fine particles of ore are directly transported to the second coarse stirring tank through the sand pump B4 and then undergo the second flotation process; S4, second-stage grinding: the coarse-grained medium ore in step S3 is fed into the second-stage pump pool B5, and after classification by the second-stage cyclone group X4, the overflow is fed into the second coarse stirring tank for the second-stage flotation process, and the sediment is fed into the second-stage ball mill Q2. The grinding slurry concentration is adjusted to 65%-68% by adding water, and the ball mill discharge is directly transported to the second coarse stirring tank through the pump pool B6 for the second-stage flotation process, thus realizing the second-stage open-circuit grinding operation.

2. A grinding method for reducing over-grinding and improving grinding efficiency of copper-nickel sulfide ore according to claim 1, characterized in that: In the step S1, high chromium balls with a specification of Ø90 are added into a first-stage ball mill, and the filling rate is required to be 34%-38%.

3. The grinding method for reducing over-grinding and improving grinding efficiency of copper-nickel sulfide ore according to claim 1, characterized in that: In the step S2, high chromium forging is added into a secondary ball mill, and the high chromium forging with a specification of Ø40×45 is used, and the filling rate is required to be 34%-37%.

4. The method for reducing over-grinding and improving grinding efficiency of copper-nickel sulfide ore according to claim 1, characterized in that: In the steps S1 and S2, the size of the sand discharge nozzles of the cyclones X1 and X2 is 70 mm, and the size of the overflow pipe is 140 mm; the size of the sand discharge nozzle of the cyclone group X3 is 85 mm, and the size of the overflow pipe is 140 mm.

5. The grinding method for reducing over-grinding and improving grinding efficiency of copper-nickel sulfide ore according to claim 1, characterized in that: In the step S2, the feed pressure of the cyclone group X3 during operation is 0.08-0.11 MPa, the overflow concentration of the cyclone group X3 is 33%-39%, and the sand concentration thereof is 75%-80%.

6. The method for reducing over-grinding and improving grinding efficiency of copper-nickel sulfide ore according to claim 1, characterized in that: The first stage grinding realizes differential grinding through a closed circuit process; the second stage grinding adopts an open circuit grinding process.

7. The grinding method for reducing over-grinding and improving grinding efficiency of copper-nickel sulfide ore according to claim 1, characterized in that: In step S4, ceramic balls are added into the second-stage ball mill, and nano-composite ceramic balls with specifications of Ø30 and Ø35 are used for grading, with a required filling rate of 40%-45% and a grinding concentration of 65%-68%.

8. The method for reducing over-grinding and improving grinding efficiency of copper-nickel sulfide ore according to claim 1, characterized in that: The size of the sand discharge nozzle of the second-stage cyclone group X4 is 70mm, the size of the overflow pipe is 140mm, the feed pressure of the second-stage cyclone group X4 during operation is 0.09-0.11Mpa, the overflow concentration of the cyclone group X4 is 24%-30%, and the sand concentration is 70%-80%.

9. A grinding method for reducing over-grinding and improving grinding efficiency of copper-nickel sulfide ore according to claim 1, characterized in that: In step S2, the slurry concentration is adjusted to 66%-67% by adding water in the pump pool.

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