Ore grinding process for nickel sulfide copper ore with high fine ore content

Abstract

The invention provides an ore grinding process for nickel sulfide copper ore with high fine ore content. The process comprises the following steps: firstly, feeding materials in a fine ore bin into a linear vibrating screen; feeding oversize materials of the linear vibrating screen into a first-stage ore grinding process; feeding undersize materials into a second-stage screening high-frequency vibrating screen; feeding oversize materials into a first-stage ore grinding process, feeding oversize materials into a third-stage screening high-frequency vibrating screen, feeding oversize products into a second-stage ore grinding process, and feeding undersize products into a flotation process; according to the method, a pre-screening link is added before first-stage ore grinding, fine-fraction materials meeting the particle size conditions of second-stage ore grinding and flotation feeding are separated out in advance, the situation that the fine-fraction materials enter the mills to cause over-grinding is avoided, and the quality of the fine-fraction materials is improved. In addition, the system treatment capacity is improved, and the ore grinding energy consumption is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of ore dressing, and specifically relates to an improved grinding and classification method for nickel sulfide and copper ore, in particular to a grinding treatment process using a linear vibrating screen and a high-frequency fine screen for pre-screening. Background Art

[0002] In the beneficiation process of nickel-copper sulfide ore, grinding is the last preparation process before the ore is selected. The purpose is to obtain a particle size product that is fully separated from useful minerals and gangue without over-grinding and meets the selection requirements. Taking a large nickel-copper sulfide ore beneficiation process as an example, a two-stage grinding process is adopted. About 14% of the fine-grained minerals in the original ore enter the first grinding and classification process, and are over-grinded after being ground by the mill. Because the existing flotation process structure cannot effectively select this part of the over-ground fine-grained minerals, it affects the stable improvement of the nickel-copper grade and recovery rate, and makes it difficult to control the magnesium oxide in the concentrate. In addition, the fine-grained minerals entering the grinding and classification process increase the mill table time, reduce the system processing capacity, and the grinding energy consumption accounts for more than 70% of the total energy consumption of the beneficiation plant, and the grinding cost remains high.

[0003] In view of the above shortcomings, the present invention provides a grinding process for nickel-copper sulfide minerals with a high powder ore content, which reduces over-grinding and improves the system processing capacity. Summary of the invention

[0004] The purpose of the present invention is to provide a grinding process for nickel-copper sulfide minerals with high powder ore content, which is an improvement on the grinding method of nickel-copper sulfide minerals with high content, and is a grinding and classification process for reducing over-grinding of nickel-copper sulfide minerals and improving the system processing capacity.

[0005] The grinding process of the nickel-copper sulfide ore with high powder ore content of the present invention comprises the following steps (1) First-stage screening: The nickel-copper sulfide ore in the powder ore bin is transported to a double-layer linear vibrating screen through a belt conveyor. The under-screen product is fed to a second-stage screening high-frequency vibrating screen, and the over-screen product is fed to a first-stage ball mill. The first layer of the double-layer linear vibrating screen has a screen size of 5 mm, the second layer has a screen size of 2 mm, and the screen area is 7.3 m 2 ×2; two double-layer linear vibrating screens are provided.

[0006] (2) Two-stage screening: The product under the first-stage screening double-layer linear vibrating screen is fed to the second-stage screening high-frequency vibrating screen for screening, and the product under the screen is fed to the third-stage screening high-frequency vibrating screen, and the product on the screen is fed to the first-stage ball mill; The second-stage screening high-frequency vibrating screen is a five-layer stacked screen with a screen size of 0.3mm-0.45mm and a total screen area of ​​10.45m 2 .

[0007] (3) Three-stage screening: The under-screen product of the second-stage high-frequency vibrating screen is fed into the third-stage high-frequency vibrating screen for screening. The under-screen product is fed into a rough mixing tank for sorting, and the over-screen product is fed into the second-stage ball mill. The three-stage screening high-frequency vibrating screen is a three-layer stacked screen with a screen size of 0.15 mm and a total screen area of ​​6.27 m 2 .

[0008] (4) Primary grinding: The primary screening product and the secondary screening product are fed into a primary ball mill. The pulp concentration is adjusted to 65%-69% by adding water. The discharged ore is fed into a cyclone group through a sand pump for inspection and classification. Steel balls are added into the first stage ball mill, and the filling rate is 34%-36%; two first stage ball mills are arranged.

[0009] (5) Inspection and classification: The discharge from the first and second stage ball mills is fed into the pump pool, where the slurry concentration is adjusted to 66%-67% by adding water, and then fed into the hydrocyclone group for inspection and classification. The overflow from the hydrocyclone group is fed into a rough mixing tank for selection, and the sand is fed into the second stage ball mill; The size of the sand discharge nozzle of the cyclone group is 85mm, and the size of the overflow pipe is 140mm. The feed pressure of the cyclone group during operation is 0.08-0.11Mpa. The overflow concentration of the cyclone group is 33%-39%, and the sand concentration is 78%-82%.

[0010] (6) Second stage grinding: The oversize product from the third stage screening and the sand settling in the cyclone are fed into the second stage ball mill. The slurry concentration is adjusted to 70%-74% by adding water. The discharged ore is fed into the cyclone group for inspection and classification.

[0011] The size of the cast iron section added in the second-stage ball mill is 40×45 mm, and the filling rate is 33%-37%; two second-stage ball mills are provided.

[0012] In summary, the present invention provides a grinding and classification process for reducing over-grinding of nickel-copper sulfide minerals and improving system processing capacity. The beneficial effect is that a pre-screening link is added before the first-stage grinding, and fine-grained materials that meet the second-stage grinding and flotation feed particle size conditions are separated in advance to avoid entering the mill and causing over-grinding. In addition, it is also beneficial to improve the system processing capacity and reduce the energy consumption of grinding. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a process flow chart of ore grinding of the present invention; Figure 2 This is the process flow chart of traditional grinding. DETAILED DESCRIPTION

[0014] The present invention will be further described in detail below in conjunction with specific embodiments and the accompanying drawings. Since the range of pre-screening of raw ore is relatively wide, the implementation methods of the present invention are not limited to the embodiments cited in the present invention.

[0015] Example 1 The ore is a pulp sample from Jinchuan nickel sulfide mine. The content of -0.15mm in the original ore is 9.62%, and the content of -0.28mm~+0.15mm is 4.8%.

[0016] The raw ore is prepared according to the process of the present invention Figure 1 The process shown: (1) First-stage screening: The nickel-copper sulfide ore in the powder ore bin is transported to the high-frequency double-layer linear vibrating screen through a belt conveyor. The under-screen product is fed to the second-stage screening high-frequency vibrating screen through the slurry pipeline, and the over-screen product is fed to the ore separator and then to the first-stage ball mill through a belt conveyor.

[0017] The first layer of double-layer linear vibrating screen has a screen size of 5mm, the second layer has a screen size of 2mm, and the screen area is 7.3m 2 ×2; Two double-layer linear vibrating screens are set up.

[0018] (2) Two-stage screening: The under-screen products of the double-layer linear vibrating screen in the first-stage screening are fed into the second-stage screening high-frequency vibrating screen for screening. The under-screen products are fed into the third-stage screening high-frequency vibrating screen through the slurry pipeline, and the over-screen products are fed into the ore separator and then fed into the first-stage ball mill through the slurry pipeline.

[0019] The mesh size of the second-stage high-frequency vibrating screen is 0.28 mm. The second-stage screening high-frequency vibrating screen is a five-layer stacked screen with a total mesh area of ​​10.45m 2 .

[0020] (3) Three-stage screening: The under-screen product of the second-stage high-frequency vibrating screen is fed into the third-stage high-frequency vibrating screen for screening. The under-screen product is fed into the pump pool through a pipeline, and then into a rough mixing tank through a sand pump for sorting. The over-screen product is fed into the ore separation box and then into the second-stage ball mill through a slurry pipeline.

[0021] The three-stage high-frequency vibrating screen is a three-layer stacked screen with a screen size of 0.15mm and a total screen area of ​​6.27m 2 The content of the product under the three-stage high-frequency vibrating screen -0.15mm is 83.56%.

[0022] (4) First-stage grinding: The first-stage screening product and the second-stage screening product are fed into a first-stage ball mill. The slurry concentration is adjusted to 67% by adding water. The discharged ore is fed into the pump pool through the slurry pipeline and enters the cyclone group through the sand pump for inspection and classification.

[0023] Among them, two first-stage ball mills are set up, and the grinding efficiency of the two first-stage ball mills is 62.5 tons / hour, and the system processing capacity is 3400 tons / day. The size ratio of the steel balls added in the filling rate of the first-stage ball mill is Ф80:Ф90=1:3, and the filling rate is 35%. The content of -0.074mm in the discharge of the two first-stage ball mills is 35.75% and 36.13%, and the content of -0.28mm~+0.074mm is 34.9% and 34.64%, respectively.

[0024] (5) Inspection and classification: The discharge from the first and second stage ball mills is fed into the pump pool. The slurry concentration is adjusted to 66% by adding water in the pump pool. The slurry is fed into the cyclone group through a sand pump and its working pressure is adjusted to 0.09-0.10 MPa for inspection and classification. The overflow from the cyclone group is fed into a coarse mixing tank through a slurry pipeline for selection. The settled sand is fed into the second stage ball mill through a slurry pipeline.

[0025] Among them, the size of the cyclone group sand discharge nozzle is 85mm, and the overflow pipe size is 140mm. The overflow concentration of the cyclone group is 34%, and the sediment concentration is 76%. The content of -0.074mm in the sediment of the cyclone group is 12.35%, and the content of -0.28mm~+0.074mm is 49.5%; the content of -0.074mm in the overflow is 63.35%.

[0026] (6) Second stage grinding: The oversize product from the third stage screening and the sand from the cyclone are fed into the second stage ball mill. The slurry concentration is adjusted to 71% by adding water. The discharged ore is fed into the pump pool through the slurry pipeline and then into the cyclone group through the sand pump for inspection and classification.

[0027] Two second-stage ball mills are set up, and the size of the cast iron section added in the second-stage ball mill is 40×45mm, and the filling rate is 35%. The content of -0.074mm in the discharge of the second-stage ball mill is 24.4%, and the content of -0.28mm~+0.074mm is 50.5% respectively.

[0028] Comparative Example The original ore is processed according to the traditional process Figure 2 The process shown: 1. First-stage grinding: The raw ore in the powder ore bin is conveyed into the first-stage ball mill (65 tons / hour) through a belt conveyor. The pulp concentration is adjusted to 68% by adding water, and the filling rate is adjusted to 35% by adding steel balls with a size ratio of Ф80:Ф90=1:1. The discharged ore is fed into the cyclone group through a sand pump for inspection and classification. 2. Inspection and classification: The discharge from the first and second stage ball mills is fed into the pump pool. The slurry concentration is adjusted to 65% by adding water in the pump pool and fed into the cyclone group. The working pressure is adjusted to 0.09-0.10Mpa for inspection and classification (the size of the cyclone sand discharge nozzle is 85mm, and the size of the overflow pipe is 140mm). The overflow of the cyclone group is fed into a rough mixing tank for selection operation, and the sand settling B3 is fed into the second stage grinding mill. 3. Second stage grinding: The sand from the cyclone is fed into the second stage ball mill. The slurry concentration is adjusted to 70% by adding water. The discharged ore is fed into the cyclone group through a sand pump for inspection and classification.

[0029] From the data comparison in Table 1, it can be seen that after adopting the process of Example 1 of this scheme, the system processing capacity is increased by 300 tons / day, the content of -0.074mm~+0.010mm (intermediate particle size) in the product particle size increases by 14.09%, and -0.010mm (over-grinding part) decreases by 14.42%.

[0030] Example 2 The ore is a pulp sample from Jinchuan nickel sulfide mine. The content of -0.15mm in the original ore is 9.62%, and the content of -0.425mm~+0.15mm is 5.96%.

[0031] The raw ore is prepared according to the process of the present invention Figure 1 The process shown: (1) First-stage screening: The nickel-copper sulfide ore in the powder ore bin is transported to the high-frequency double-layer linear vibrating screen through a belt conveyor. The under-screen product is fed to the second-stage screening high-frequency vibrating screen through the slurry pipeline, and the over-screen product is fed to the ore separator and then to the first-stage ball mill through a belt conveyor.

[0032] The first layer of double-layer linear vibrating screen has a screen size of 5mm, the second layer has a screen size of 2mm, and the screen area is 7.3m 2 ×2; Two double-layer linear vibrating screens are set up.

[0033] (2) Two-stage screening: The under-screen products of the double-layer linear vibrating screen in the first-stage screening are fed into the second-stage screening high-frequency vibrating screen for screening. The under-screen products are fed into the third-stage screening high-frequency vibrating screen through the slurry pipeline, and the over-screen products are fed into the ore separator and then fed into the first-stage ball mill through the slurry pipeline.

[0034] The mesh size of the second-stage high-frequency vibrating screen is 0.425 mm. The second-stage screening high-frequency vibrating screen is a five-layer stacked screen with a total mesh area of ​​10.45m 2 .

[0035] (3) Three-stage screening: The under-screen product of the second-stage high-frequency vibrating screen is fed into the third-stage high-frequency vibrating screen for screening. The under-screen product is fed into the pump pool through a pipeline, and then into a rough mixing tank through a sand pump for sorting. The over-screen product is fed into the ore separation box and then into the second-stage ball mill through a slurry pipeline.

[0036] The three-stage high-frequency vibrating screen is a three-layer stacked screen with a screen size of 0.15mm and a total screen area of ​​6.27m 2 The content of the product under the three-stage high-frequency vibrating screen -0.15mm is 84.17%.

[0037] (4) First-stage grinding: The first-stage screening product and the second-stage screening product are fed into a first-stage ball mill. The slurry concentration is adjusted to 67% by adding water. The discharged ore is fed into the pump pool through the slurry pipeline and enters the cyclone group through the sand pump for inspection and classification.

[0038] Among them, two first-stage ball mills are set up, and the grinding efficiency of the two first-stage ball mills is 62.5 tons / hour, and the system processing capacity is 3450 tons / day. The size of the steel balls added in the filling rate of the first-stage ball mill is Ф90, and the filling rate is 35%. The content of -0.074mm in the discharge of the two first-stage ball mills is 36.45% and 35.96%, and the content of -0.425mm~+0.074mm is 34.78% and 35.1% respectively.

[0039] 5. Inspection and grading: The discharge from the first-stage ball mill and the second-stage ball mill is fed into the pump pool. The slurry concentration is adjusted to 67% by adding water in the pump pool. It is fed into the cyclone group through a sand pump and its working pressure is adjusted to 0.09-0.10Mpa for inspection and grading. The overflow of the cyclone group is fed into a rough mixing tank through a slurry pipeline to enter the selection operation, and the settled sand is fed into the second-stage ball mill through a slurry pipeline.

[0040] Among them, the size of the cyclone group sand discharge nozzle is 85mm, and the overflow pipe size is 140mm. The overflow concentration of the cyclone group is 34%, and the sediment concentration is 77%. The content of -0.074mm in the sediment of the cyclone group is 12.35%, and the content of -0.425mm to +0.074mm is 52.23%; the content of -0.074mm in the overflow is 63.28%.

[0041] 6. Second stage grinding: The overscreen products from the third stage screening and the cyclone sand are fed into the second stage ball mill. The slurry concentration is adjusted to 71% by adding water. The discharged ore is fed into the pump pool through the slurry pipeline and enters the cyclone group through the sand pump for inspection and classification.

[0042] Two second-stage ball mills are set up, and the size of the cast iron section added in the second-stage ball mill is 40×45mm, and the filling rate is 35%. The content of -0.074mm in the discharge of the second-stage ball mill is 25.15%, and the content of -0.425mm~+0.074mm is 52.6%.

[0043] From the data comparison in Table 2, it can be seen that after adopting this solution, the system processing capacity increased by 350 tons / day, the content of -0.074mm~+0.005mm (intermediate particle size) in the product particle size increased by 14.63%, and the content of -0.010mm (over-grinding part) decreased by 15.2%.

Claims

1. A grinding process for nickel-copper sulfide ore with high powder ore content, comprising the following steps: (1) First-stage screening: The nickel-copper sulfide ore in the powder ore bin is transported to a double-layer linear vibrating screen through a belt conveyor. The under-screen product is fed to a second-stage screening high-frequency vibrating screen, and the over-screen product is fed to a first-stage ball mill. (2) Two-stage screening: The product under the first-stage screening double-layer linear vibrating screen is fed to the second-stage screening high-frequency vibrating screen for screening, and the product under the screen is fed to the third-stage screening high-frequency vibrating screen, and the product on the screen is fed to the first-stage ball mill; (3) Three-stage screening: The under-screen product of the second-stage high-frequency vibrating screen is fed into the third-stage high-frequency vibrating screen for screening. The under-screen product is fed into a rough mixing tank for sorting, and the over-screen product is fed into the second-stage ball mill. (4) Primary grinding: The primary screening product and the secondary screening product are fed into a primary ball mill. The pulp concentration is adjusted to 65%-69% by adding water. The discharged ore is fed into a cyclone group through a sand pump for inspection and classification. (5) Inspection and classification: The discharge from the first and second stage ball mills is fed into the pump pool, where the slurry concentration is adjusted to 66%-67% by adding water, and then fed into the hydrocyclone group for inspection and classification. The overflow from the hydrocyclone group is fed into a rough mixing tank for selection, and the sand is fed into the second stage ball mill; (6) Second stage grinding: The oversize product from the third stage screening and the cyclone sand are fed into the second stage ball mill. The slurry concentration is adjusted to 70%-74% by adding water. The discharged ore is fed into the cyclone group for inspection and classification.

2. The grinding process of nickel-copper sulfide ore with high powder ore content according to claim 1, characterized in that: The first layer of the double-layer linear vibrating screen has a screen size of 5 mm, the second layer has a screen size of 2 mm, and the screen area is 7.3 m 2 ×2; two double-layer linear vibrating screens are provided.

3. The grinding process of nickel-copper sulfide ore with high powder ore content according to claim 1, characterized in that: The second-stage screening high-frequency vibrating screen is a five-layer stacked screen with a screen size of 0.3mm-0.45mm and a total screen area of ​​10.45m 2 .

4. The grinding process of nickel-copper sulfide ore with high powder ore content according to claim 1, characterized in that: The three-stage screening high-frequency vibrating screen is a three-layer stacked screen with a screen size of 0.15 mm and a total screen area of ​​6.27 m 2 .

5. The grinding process of nickel-copper sulfide ore with high powder ore content according to claim 1, characterized in that: Steel balls are added into the first stage ball mill, and the filling rate is 34%-36%; two first stage ball mills are arranged.

6. The grinding process of nickel-copper sulfide ore with high powder ore content according to claim 1, characterized in that: The size of the sand discharge nozzle of the cyclone group is 85mm, and the size of the overflow pipe is 140mm.

7. The grinding process of nickel-copper sulfide ore with high powder ore content according to claim 1, characterized in that: The feed pressure of the cyclone group when working is 0.08-0.11Mpa.

8. The grinding process of nickel-copper sulfide ore with high powder ore content according to claim 1, characterized in that: The overflow concentration of the cyclone group is 33%-39%, and the sand concentration is 78%-82%.

9. The grinding process of nickel-copper sulfide ore with high powder ore content according to claim 1, characterized in that: The size of the cast iron section added in the second-stage ball mill is 40×45 mm, and the filling rate is 33%-37%; two second-stage ball mills are provided.

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