Pre-separation method suitable for refractory copper-nickel sulfide ore

Abstract

The invention discloses a pre-separation method suitable for refractory copper-nickel sulfide ore, and belongs to the technical field of mineral processing. The method comprises the following steps: 1) ore washing and grading: separating a-1mm fine fraction and a + 1mm coarse fraction through a roller wiping ore washer and a 1mm screen; (2) coarse grain treatment, wherein coarse grains with the particle size of + 1 mm are subjected to first-section ore grinding classification and then subjected to flotation; 3) fine particle treatment: concentrating and grading fine particles with the particle size of-1 mm, directly floating dissociated minerals, and recycling overflow water; according to the method, the problems that fine particles are over-ground, the energy consumption is high and the water consumption is large in a traditional process are solved, the ore grinding power consumption is reduced by 3-5 kWh / t, the comprehensive recovery rate of copper and nickel is increased to 88-90%, and green and efficient development of the refractory copper-nickel sulfide ore is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of mineral processing, and particularly relates to a pre-sorting method suitable for complex and refractory copper-nickel sulfide ore, especially suitable for optimization and upgrading of the traditional process of 'two-stage one-closed-circuit crushing + two-milling two-selection', which solves the problems of high energy consumption of fine ore, over-grinding of primary fine particles and high energy consumption of grinding by means of 1mm size accurate classification, coarse and fine particle directional treatment and circulating water-saving technology, and realizes green and efficient separation of copper-nickel sulfide ore. BACKGROUND

[0002] Copper-nickel sulfide ore is the core source of strategic metals such as nickel, copper and cobalt, and its beneficiation efficiency directly determines the resource utilization rate and economic benefit of enterprises. With the increase of mining years, two key problems of domestic typical complex and refractory copper-nickel sulfide ore are as follows: The proportion of lean ore increases significantly: the depletion of rich ore resources leads to the proportion of lean ore entering the selection from 30% in the early stage to more than 60%, the gangue mineral content increases, the copper-nickel grade decreases, and the beneficiation difficulty increases significantly; The proportion of fine particle minerals increases: due to the influence of the structure of primary ore and mining process, the proportion of fine particles below 1mm in the raw ore increases from 5% to 10-15%, which has high surface energy and is easy to be slimed, and is difficult to be efficiently separated by traditional process.

[0003] The traditional 'two-milling two-selection' process has obvious defects: 95% of the materials after crushing are below 12mm and enter the ball mill, but the proportion of materials below 5mm is 49% and the proportion of materials below 1mm is 15%; the fine particles below 1mm (Mohs hardness 4-5) need to be ground with coarse particles for two times, which is easy to be slimed and form'slime cover', which hinders the adsorption of flotation reagents, resulting in reduced recovery rate, and the invalid grinding of this part accounts for 3-5% of the total grinding energy consumption, and causes the imbalance problem of 'over-grinding of fine particles and under-grinding of coarse particles'.

[0004] Existing washing technology is mostly used for bauxite, iron oxide ore and the like, and relies on a large amount of water resources and equipment designed for oxidized ore, and the washing wastewater is mostly directly discharged or simply reused; the fine particles below 1mm of refractory copper-nickel sulfide ore contain a large amount of useful metals and need to be recovered by flotation, and cannot be directly discarded. Therefore, the industry urgently needs a new generation of separation method of 'accurate classification - directional treatment - recycling' to fundamentally solve the technical bottleneck of the traditional process. SUMMARY

[0005] In view of the problems of over-grinding, high consumption and uncoordinated process of the traditional process, the purpose of the present application is to provide a pre-sorting method suitable for refractory sulfide copper-nickel ore, which realizes the goal of "reducing over-grinding, saving water in circulation, improving efficiency and reducing cost" by separating fine particles below 1mm in advance and optimizing the processing path, and improves the comprehensive recovery rate and resource utilization rate of refractory sulfide copper-nickel ore.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is: A pre-sorting method suitable for refractory sulfide copper-nickel ore, comprising the following steps: (1) Washing and grading: the sulfide copper-nickel ore to be ground material with particle size ≤12mm, water content ≤8% and fine particle level below 1mm accounting for 5%-20% after crushing is conveyed to the drum wiping washing machine by the belt conveyor 1; the high-pressure spraying system of the drum wiping washing machine is started, and the material is conveyed by the spiral device in the drum, and is screened by the 1mm standard screen mesh on the drum cylinder, the error of the screen mesh is ±0.1mm, so that the -1mm fine particle level forms a slurry flow into the pump pool below, and the +1mm coarse particle level is discharged from the discharge port to the belt conveyor 2; (2) Directional treatment of +1mm coarse particle level: the +1mm coarse particle level is conveyed to the first-stage ball mill for one-stage grinding by the belt conveyor 2; the grinding product is conveyed to the hydrocyclone 1 for grading by the pump 1, and the overflow 1 with -200 mesh content ≥65% after grading flows into the first-stage flotation tank 1, and the sand 1 flows into the first-stage secondary ball mill; the grinding product of the first-stage secondary ball mill is graded by the hydrocyclone 2, and the overflow 2 with -200 mesh content ≥65% after grading flows into the first-stage flotation tank 1, and the sand 2 returns to the first-stage secondary ball mill to form a closed-circuit grinding; (3) Gradient treatment of -1mm fine particle level: the -1mm slurry in the pump pool is conveyed to the small thickener, and is thickened to a slurry concentration of 35%-45%; the overflow water of the thickener is conveyed to the high-pressure spraying system for recycling by the pump 2; the thickened slurry is conveyed to the hydrocyclone 3 for grading by the pump 3, and the overflow 3 with -200 mesh content ≥65% after grading flows into the first-stage flotation tank 1, and the sand 3 flows into the first-stage secondary ball mill; (4) two-stage grinding and flotation: the tailings of the first-stage flotation tank 1 are pumped into the second-stage ball mill pump tank by pump 4, and then are delivered to the hydrocyclone 4 for classification; the overflow 4 with a -200 mesh content of 85% or more is fed into the second-stage flotation tank 2, and the underflow 4 is fed into the second-stage ball mill; the grinding product of the second-stage ball mill is returned to the hydrocyclone 4 to form a closed-circuit grinding, and the grinding product has a -0.074 mm content of 85% or more; the first-stage flotation concentrate collected from the first-stage flotation tank 1 and the second-stage flotation concentrate collected from the second-stage flotation tank 2 are collected to obtain a copper-nickel comprehensive concentrate; (5) process coordination control: the washing water flow is dynamically adjusted according to the turbidity of the overflow of the small thickener, and the washing water flow is increased by 10%-20% when the turbidity is greater than 500 NTU; the washing water flow, the underflow concentration of the thickener and the grinding fineness are monitored in real time by the PLC control system to realize automatic adjustment of the whole process.

[0007] Preferably, in step (1), the copper-nickel sulfide ore to be ground contains copper-nickel sulfide minerals and gangue minerals, the copper-nickel sulfide minerals are chalcopyrite and pentlandite, the gangue minerals are olivine and pyroxene, and the content of dissociated minerals in the fine fraction is 20%-30%.

[0008] Preferably, in step (1), based on a 5t / h ore processing capacity, the washing water flow of the high-pressure spray system is 3-5m³ / h, preferably 4m³ / h; the scrubbing time of the drum scrubber is 20-40s, and the rotating speed is 18r / min; the residual amount of -1mm particles in the +1mm coarse particles after screening is less than or equal to 5%, and the content of +1mm particles in the -1mm slurry is less than or equal to 3%.

[0009] Preferably, in steps (2) and (3), the flotation conditions of the first-stage flotation tank 1 are as follows: the slurry concentration is 30%-40%, the xanthate collector is added at a dosage of 100-150g / t, and the frother is added at a dosage of 30-50g / t.

[0010] Preferably, in step (3), the concentration of the -1mm slurry before thickening in the small thickener is 12.5%-18.5%.

[0011] Preferably, in steps (1)-(4), the hydrocyclones 1, 2, 3 and 4 are arranged on the same platform above the first-stage flotation tank 1.

[0012] The core technical scheme of the application is "1mm classification as the boundary, coarse and fine particle directional treatment, full-process water circulation + intelligent control", and the technical logic and advantages of each step are as follows: Washing and grading: With 1mm as the particle size threshold, coarse and fine particles are efficiently separated by drum wiping washer + high-pressure spraying + standard screen to avoid fine particles below 1mm entering multi-stage grinding with coarse particles, reducing over-grinding from the source; Coarse particle directional grinding: +1mm coarse particles are only subjected to one-stage grinding and then flotation, reducing grinding amount by 15-20% compared with traditional process, and reducing unit power consumption; Fine particle gradient treatment: -1mm fine particles are subjected to concentration to improve concentration stability, and the dissociated minerals after grading are directly subjected to flotation, reducing reagent consumption and argillaceous interference; Two-stage precise regrinding: Only the tailings (undissociated coarse particles) of one-stage flotation are subjected to regrinding to avoid ineffective grinding and improve comprehensive recovery rate; Circulation and intelligent control: The overflow water of the thickener is reused to reduce water supplement demand by 50%, and the PLC system adjusts parameters in real time to ensure process stability.

[0013] The beneficial effects of the present application are: 1. Energy consumption is reduced: grinding amount is reduced by 15-20%, and unit ore grinding power consumption is reduced by 3-5kWh / t.

[0014] 2. Recovery rate is improved: the single mineral dissociation degree of copper-nickel minerals reaches 80-85%, the comprehensive recovery rate is improved to 88-90%, and the one-stage flotation recovery rate is increased by 2-3% compared with traditional process.

[0015] 3. Water saving and reagent reduction: washing water recycling reduces the amount of supplementary water by 50% and the amount of reagent consumption by 15-20%.

[0016] 4. Process optimization: process stability is improved by 40-50%, argillaceous content in flotation foam is reduced by 70%, and separation efficiency is significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a pre-sorting method process flowchart suitable for refractory sulfide copper-nickel ore. DETAILED DESCRIPTION

[0018] The following takes a 5t / h refractory sulfide copper-nickel ore treatment scale as an example to explain the implementation process of the present application in detail: 1. Raw material preparation The material to be treated is the crushed ore bin material to be ground, with particle size ≤12mm, of which the fine particle level below 1mm accounts for 15% and the moisture content is 6%; the material contains chalcopyrite (copper-nickel mineral) and olivine (gangue mineral), and the dissociated mineral in the fine particle level accounts for 25%.

[0019] 2. Washing and grading (1mm precise separation) The material to be ground is sent into the drum scrubber by the belt conveyor 1, and the high-pressure spray system (washing water flow 4 m³ / h) is started. The drum speed is adjusted to 18 r / min, and the material residence time is controlled to 30 s (to ensure sufficient scrubbing), and the material is screened through a 1 mm standard screen. After screening, the -1 mm fine fraction forms a slurry (concentration 15%) that flows into the pump pool, and the +1 mm coarse fraction (-1 mm residue 3%) is transported by the belt conveyor 2 to the first-stage ball mill.

[0020] 3. Directional processing of the +1 mm coarse fraction First-stage primary grinding: After grinding the +1 mm coarse fraction by the first-stage ball mill, the product is transported by pump 1 to the hydrocyclone 1 for classification, and the overflow 1 (-200 mesh fraction 68%) flows into the first-stage flotation tank 1. First-stage secondary grinding: The underflow 1 of the hydrocyclone 1 is fed into the first-stage secondary ball mill, and the ground product is classified by the hydrocyclone 2, with the overflow 2 (-200 mesh fraction 67%) entering the first-stage flotation tank 1, and the underflow 2 returning to the first-stage secondary ball mill to form a closed-circuit grinding circuit. First-stage flotation: The first-stage flotation tank 1 is added with xanthate collector 120 g / t and frother 40 g / t, and the pulp concentration is controlled to 32%, and the first-stage flotation concentrate (copper and nickel grades meet the requirements) is obtained after flotation.

[0021] 4. Gradient processing of the -1 mm fine fraction Thickening: The -1 mm pulp (concentration 15%) in the pump pool is transported to the small thickener, and the concentration is thickened to 40%; the overflow water from the thickener (15% of the total, with a solid content of 1.5%) is transported by pump 2 to the high-pressure spray system for reuse. Classification: After thickening, the pulp is transported by pump 3 to the hydrocyclone 3, and after classification, the overflow 3 (-200 mesh fraction 66%) enters the first-stage flotation tank 1, and the underflow 3 enters the first-stage secondary ball mill. Co-flotation: Overflow 3 is mixed and floated with overflow 1 and 2, and the clay content in the flotation froth is reduced by 72% compared to the traditional process.

[0022] 5. Second-stage grinding and flotation The first-stage flotation tailings (containing undissociated coarse particles) discharged from the first-stage flotation tank 1 flow into the second-stage ball mill pump pool, and are transported by pump 4 to the hydrocyclone 4 for classification. The underflow 4 of the hydrocyclone 4 enters the second-stage ball mill, and the grinding product returns to the hydrocyclone 4 to form a closed-circuit grinding circuit. The overflow 4 (-200 mesh 86%) of the hydrocyclone 4 enters the second-stage flotation tank 2, and the second-stage flotation concentrate is obtained after flotation; the first-stage and second-stage flotation concentrates are combined, and the comprehensive recovery rate of copper and nickel reaches 89%.

[0023] 6. Process coordination control The following parameters are monitored in real time by the PLC control system: washing water flow (stabilized at 4 m³ / h), thickener underflow concentration (40%), and first-stage grinding fineness (-200 mesh 68%); when the thickener overflow turbidity rises to 550 NTU, the washing water flow is automatically increased to 4.6 m³ / h to ensure the classification effect.

Claims

1. A pre-concentration process suitable for refractory copper nickel sulphide ores characterised in that, The method comprises the following steps: (1) washing and grading: the crushed material with particle size of less than or equal to 12 mm, water content of less than or equal to 8%, and fine particle content of 5%-20% below 1 mm is conveyed to the drum wiping washing machine by the belt conveyor 1; the high-pressure spraying system of the drum wiping washing machine is started, and the material is conveyed by the spiral device in the drum; the material is screened by the 1 mm standard screen in the drum body, the screen error is ±0.1 mm, the fine particle level of less than 1 mm is formed into slurry and flows into the pump pool below, and the coarse particle level of more than 1 mm is discharged from the discharge port to the belt conveyor 2; (2) directional treatment of the coarse particle level of more than 1 mm: the coarse particle level of more than 1 mm is conveyed to the first-stage ball mill by the belt conveyor 2 for one-stage grinding; the grinding product is conveyed to the hydrocyclone 1 for grading by the pump 1; the overflow 1 with a content of -200 mesh of more than or equal to 65% after grading flows into the first-stage flotation tank 1, and the sand 1 flows into the first-stage secondary ball mill; the grinding product of the first-stage secondary ball mill is graded by the hydrocyclone 2; the overflow 2 with a content of -200 mesh of more than or equal to 65% after grading flows into the first-stage flotation tank 1, and the sand 2 returns to the first-stage secondary ball mill to form a closed-circuit grinding; (3) gradient treatment of the fine particle level of less than 1 mm: the slurry of less than 1 mm in the pump pool is conveyed to the small thickener, and is thickened to a slurry concentration of 35%-45%; the overflow water of the thickener is conveyed to the high-pressure spraying system for recycling by the pump 2; the thickened slurry is conveyed to the hydrocyclone 3 for grading by the pump 3; the overflow 3 with a content of -200 mesh of more than or equal to 65% after grading flows into the first-stage flotation tank 1, and the sand 3 flows into the first-stage secondary ball mill; (4) second-stage grinding and flotation: the first-stage flotation tailings discharged from the first-stage flotation tank 1 flow into the pump pool of the second-stage ball mill, are conveyed to the hydrocyclone 4 for grading by the pump 4; the overflow 4 with a content of -200 mesh of more than or equal to 85% after grading flows into the second-stage flotation tank 2, and the sand 4 flows into the second-stage ball mill; the grinding product of the second-stage ball mill returns to the hydrocyclone 4 to form a closed-circuit grinding, and the content of -0.074 mm in the grinding product is more than or equal to 85%; the first-stage flotation concentrate of the first-stage flotation tank 1 and the second-stage flotation concentrate of the second-stage flotation tank 2 are collected to obtain a copper-nickel comprehensive concentrate; (5) coordinated control of the process: the washing water flow is dynamically adjusted according to the turbidity of the overflow of the small thickener; when the turbidity is greater than 500 NTU, the washing water flow is increased by 10%-20%; the washing water flow, the thickener underflow concentration and the grinding fineness are monitored in real time by the PLC control system to realize automatic adjustment of the whole process.

2. The method of claim 1, wherein, In step (1), the grinding material of the copper-nickel sulfide ore contains copper-nickel sulfide minerals and gangue minerals; the copper-nickel sulfide minerals are chalcopyrite and pentlandite; the gangue minerals are olivine and augite; and the content of dissociated minerals in the fine particle level is 20%-30%.

3. The method of claim 1, wherein, In step (1), based on the ore processing scale of 5 t / h, the washing water flow rate of the high-pressure spraying system is 3-5 m³ / h, preferably 4 m³ / h; the scrubbing time of the drum scrubbing washer is 20-40 s, and the rotating speed is 18 r / min; the residual amount of -1 mm in +1 mm coarse particles after screening is ≤5%, and the content of +1 mm particles in -1 mm slurry is ≤3%.

4. The method of claim 1, wherein, In steps (2) and (3), the flotation conditions of the first-stage flotation tank 1 are as follows: the slurry concentration is 30%-40%, the addition of xanthate collector is 100-150 g / t, and the addition of foaming agent is 30-50 g / t.

5. The method of claim 1, wherein, In step (3), the concentration of -1 mm slurry before being concentrated by the small thickener is 12.5%-18.5%.

6. The method of claim 1, wherein, In steps (1)-(4), the hydrocyclones 1, 2, 3, and 4 are arranged on the same platform higher than the first-stage flotation tank 1.

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