Process for recovering low-grade copper in semi-autogenous grinding hard rock of copper ore dressing plant

Abstract

The invention discloses a process for recovering low-grade copper in semi-autogenous grinding hard rock of a copper ore dressing plant, which adopts a combined process of high-pressure roller grinding crushing, coarse grain dense medium separation and fine grain Nelson separation, that is, after the semi-autogenous grinding hard rock is crushed by a high-pressure roller grinding, coarse grain materials are fed into a dense medium separator for separation, and fine grain materials are fed into a fine grain separator for separation; and the fine-fraction materials are fed into a Nelson centrifugal separator for separation, dense medium concentrate and concentrate of the Nelson centrifugal separator are combined into copper concentrate, and dense medium separation tailings and separation tailings of the Nelson centrifugal separator are combined into final tailings. The physical beneficiation method is used for enriching the copper ore, compared with a conventional flotation method, the physical beneficiation method is more beneficial to the environment, pollution is reduced, the technological process is simple and easy to operate, cost reduction is more facilitated, and a new reliable way is provided for economic recovery of the copper ore in the semi-autogenous grinding hard rock.

Description

Technical Field

[0001] The invention belongs to the technical field of copper ore dressing, and in particular relates to a process for recovering low-grade copper from semi-autogenous grinding stone in a copper ore dressing plant. Background Art

[0002] One of the key operations in the mineral processing process is grinding. After years of production practice, the traditional grinding process has shown the characteristics of long process flow, multiple equipment types, large consumption of metal balls, high infrastructure investment and production costs; while the semi-autogenous grinding circuit has a simple process flow, simplified two-stage crushing and screening equipment, simple configuration, low investment, and has been used by more and more mines at home and abroad, especially in large copper ore dressing plants.

[0003] With the increasing popularity of the semi-autogenous grinding process in large domestic mines, different mills have adopted different methods to deal with the stubborn stones produced in the semi-autogenous grinding process. The semi-autogenous grinding process is prone to produce stubborn stones in production. The so-called stubborn stones are blocky ores that are difficult to grind finely formed in the semi-autogenous grinding process. The stubborn stones often contain a large amount of target minerals. If they are discarded at will without treatment, it will not only waste mineral resources, but also cause environmental pollution and damage to the surrounding environment.

[0004] At present, the copper grade in the semi-autogenous grinding stone of copper concentrators is low, mainly in the form of primary copper sulfide and secondary copper sulfide. The particle size of useful minerals is uneven and the mineral composition is complex. The traditional flotation process cannot recover the copper minerals well, which is a very difficult to select low-grade copper ore. With the acceleration of the global industrialization process and the continuous growth of demand for mineral resources, the large-scale development and utilization of mineral resources have become an important pillar of the world's economic development today. However, in this process, the resources of easy-to-mine, easy-to-select and high-grade copper ore are decreasing, which makes low-grade and complex and difficult-to-process copper ore gradually become the main resources in the future. Therefore, it is necessary to recycle the low-grade copper in the semi-autogenous grinding stone of copper concentrators. Summary of the invention

[0005] The purpose of the present invention is to address the problem that it is currently difficult to recover low-grade copper from semi-autogenous grinding stone in copper ore dressing plants, and to provide a recovery process for low-grade copper from semi-autogenous grinding stone in copper ore dressing plants with low energy consumption, environmental friendliness and high recovery rate. The process adopts a combined process of high-pressure roller mill crushing-coarse-grained heavy medium separation-fine-grained Nelson separation, which can effectively enrich copper minerals and achieve efficient recovery.

[0006] To achieve the above-mentioned object of the present invention, the present invention provides a process for recovering low-grade copper from semi-autogenous grinding stone in a copper ore dressing plant, which is implemented by the following process and steps:

[0007] S1 High Pressure Roller Mill - Screening

[0008] The semi-autogenous grinding stone of the copper ore dressing plant is fed into a high-pressure roller mill for high-pressure roller grinding. After the grinding, the material is fed into a screening operation with a sieve hole size of 0.5 mm to obtain a coarse particle product with a particle size of ≥0.5 mm and a fine particle product with a particle size of <0.5 mm.

[0009] S2 Screen Coarse Grain Product Heavy Medium Separation

[0010] The coarse particle size product obtained in step S1 is fed into a heavy medium separation operation, wherein the heavy medium separation operation adopts a one-coarse and one-sweep process to obtain a heavy medium separation copper concentrate 1 and a heavy medium separation copper concentrate 2, respectively, and discharge the heavy medium separation and scavenging tailings; the separation equipment used in the heavy medium separation operation is a heavy medium cyclone;

[0011] S3 undersize fine particle product centrifugal gravity separation

[0012] The undersize fine-particle product obtained in step S1 is fed into a centrifugal gravity separation process, wherein the centrifugal gravity separation process adopts a one-roughing and one-sweeping process to obtain centrifugal gravity separation copper concentrate 3 and centrifugal gravity separation copper concentrate 4, respectively, and discharge the centrifugal gravity separation and scavenging tailings; the centrifugal gravity separation process adopts a Nelson centrifugal concentrator as the separation equipment;

[0013] S4 combines the heavy medium separation copper concentrate 1 and the heavy medium separation copper concentrate 2 obtained in step S2 and the centrifugal gravity separation copper concentrate 3 and the centrifugal gravity separation copper concentrate 4 obtained in step S3 into the final copper concentrate; combines the heavy medium separation scavenging tailings discharged from step S2 and the centrifugal gravity separation scavenging tailings discharged from step S3 into the final total tailings.

[0014] Preferably, in step S1, the crushing particle size of the high pressure roller mill is set to 3-5 mm, preferably 3 mm.

[0015] Preferably, in step S2, the heavy medium separation operation uses a heavy medium powder and water, wherein the heavy medium powder is a kind of ferrosilicon or magnetite that is ground into powder, and the particle size is less than 0.045 mm, and the mass content of the particle size is in the range of 80% to 90%; The heavy medium separation operation uses a heavy medium powder and water, wherein the heavy medium powder is a kind of ferrosilicon or magnetite that is ground into powder, and the particle size is less than 0.045 mm, and the mass content of the particle size is in the range of 80% to 90%;

[0016] Preferably, in step S3, the centrifugal force strength of the Nelson centrifugal concentrator is controlled within the range of 40 to 70 g, preferably within the range of 50 to 60 g, and the flushing water flow rate is between 3 and 8 L / min, preferably between 4 and 6 L / min.

[0017] The centrifugal force intensity described in the present invention refers to the ratio of the centrifugal speed to the gravity speed.

[0018] Compared with the prior art, the process for recovering low-grade copper from semi-autogenous grinding stone in a copper ore dressing plant of the present invention has the following advantages:

[0019] (1) The present invention adopts a combined process of high-pressure roller mill crushing-coarse-grained heavy medium separation-fine-grained Nelson separation. The semi-autogenous grinding stone uses a high-pressure roller mill to replace medium and fine crushing and coarse grinding, thereby achieving more crushing and less grinding and reducing energy consumption. The coarse-grained grade is separated by heavy medium separation, and the fine-grained grade is separated by Nelson concentrator. The combination of heavy medium and Nelson concentrator fully guarantees the recovery of useful minerals in each particle size.

[0020] (2) The present invention uses a physical beneficiation method to enrich copper ore, which is more beneficial to the environment and reduces pollution compared to conventional flotation methods. The process is simple and easy to operate, which is more conducive to reducing costs and provides a new way to achieve economic recovery of copper minerals in semi-autogenous grinding stone.

[0021] (3) Compared with the traditional flotation process, the copper grade in the copper concentrate is increased by more than 1.2 percentage points and the copper recovery rate is increased by more than 8 percentage points after adopting the process of the present invention, achieving a significant increase in both the grade of the iron concentrate and the copper recovery rate, and reducing the operating cost by more than 35%, with a very significant effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a principle process flow chart of a process for recovering low-grade copper from semi-autogenous grinding stone in a copper ore dressing plant. DETAILED DESCRIPTION

[0023] To further describe the present invention, a process for recovering low-grade copper from semi-autogenous grinding stone in a copper ore dressing plant of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be noted that any modification, equivalent replacement, improvement, etc. made within the technical ideas and principles of the present invention should be included in the protection scope of the present invention.

[0024] Example

[0025] The low-grade copper ore used in this embodiment is a semi-autogenous grinding product of a copper mine in Tibet, with a particle size of -30mm, a main valuable element Cu content of 0.356%, copper minerals are mainly chalcopyrite and chalcocite, followed by bornite, arsenic copper ore, covellite, etc., and non-metallic minerals are mainly quartz, plagioclase, potassium feldspar, etc. Copper minerals mainly exist in the form of primary copper sulfide, accounting for 58.59% of the total copper ratio, followed by secondary copper sulfide, accounting for 25.35% of the total copper, combined with oxidized copper accounting for 8.17% of the total copper, and free oxidized copper accounting for 7.89%; primary copper sulfide is mainly chalcopyrite, secondary copper sulfide minerals are mainly chalcocite and a small amount of bornite, covellite, arsenic copper ore, and also contain very small amounts of malachite, azurite and other oxidized copper minerals. The main copper mineral chalcopyrite is mostly in irregular granular form and intergrows with pyrite and gangue minerals. Some chalcopyrite is replaced by chalcocite or bornite to form copper sulfide mineral aggregates. Copper sulfide is mainly inlaid with fine and micro-fine particles, mainly distributed at -0.07mm, with a distribution rate of 79.63%, and the distribution rate of micro-fine particles at -0.01mm is 16.30%.

[0026] In the embodiment, the process for recovering low-grade copper from semi-autogenous grinding stone in a copper ore dressing plant of the present invention is implemented according to the following process steps:

[0027] (1) crushing the -30 mm semi-autogenous stone medium-crushed product to -3 mm by high-pressure roller mill;

[0028] (2) Screening with a 0.5 mm vibrating screen to obtain coarse-grained materials of -3 + 0.5 mm and fine-grained materials of less than 0.5 mm;

[0029] (3) feeding the coarse-grained material of -3+0.5 mm into a heavy medium cyclone for primary heavy medium separation, wherein the heavy suspension used for the heavy medium separation is prepared by mixing ferrosilicon with water after grinding, and its particle size is -0.045 mm with a mass content of 90%, thereby obtaining a heavy medium separation copper concentrate 1 and a primary heavy medium separation tailing; feeding the primary heavy medium separation tailing into a secondary heavy medium separation operation, thereby obtaining a heavy medium separation copper concentrate 2 and a secondary heavy medium separation tailing; and the secondary heavy medium separation operation also uses a heavy medium cyclone;

[0030] (4) feeding the -0.5 mm fine-grained material into a Nelson centrifugal concentrator for primary separation, with a centrifugal force strength of 60 g and a flushing water flow rate of 5 L / min, to obtain a centrifugal gravity separation copper concentrate 3 and a primary centrifugal gravity separation tailing; feeding the primary centrifugal gravity separation tailing into a Nelson concentrator for secondary centrifugal gravity separation, to obtain a centrifugal gravity separation copper concentrate 4 and a secondary centrifugal gravity separation tailing;

[0031] (5) The heavy medium separation copper concentrate 1, the heavy medium separation copper concentrate 2, the centrifugal gravity separation copper concentrate 3, and the centrifugal gravity separation copper concentrate 4 are combined into copper concentrate; the secondary heavy medium separation tailings and the secondary heavy medium separation tailings are combined into the total tailings. The test results are shown in Table 1.

[0032] Comparative Example

[0033] The comparative example adopts the traditional flotation method for mineral processing. The -30mm semi-autogenous stone medium crushing product is crushed to -2mm by jaw crusher and roller crusher, and then enters the ball mill to grind to -0.074mm, accounting for 87%, and then floated. The flotation process is one roughing and two scavenging. Lime is used as the adjusting agent, butyl xanthate is used as the collecting agent, and pine oil is used as the frother. The amount of roughing adjusting agent is 6000g / t, the collecting agent is 100g / t, and the frother is 20g / t. The amount of scavenging agent is reduced accordingly. The test results are shown in Table 1.

[0034] Table 1 Comparison of test results of the present invention and traditional flotation method

[0035]

[0036] As can be seen from Table 1, compared with the traditional flotation process, the copper grade in the copper concentrate after the process of the present invention is increased from 4.742% to 5.993%, an increase of 26.38%, and the copper recovery rate is increased from 58.93% to 67.30%, achieving a significant increase in both the grade of the iron concentrate and the copper recovery rate, and reducing the operating cost by more than 35%, achieving unexpected technical and economic effects. In particular, the high-pressure roller mill crushing-coarse-grained heavy medium separation-fine-grained Nelson separation combined process adopted by the present invention is a green and clean process, which is very friendly to the environment.

[0037] The above are embodiments of the present invention, but the above examples are only used to help understand the method and core ideas of the present invention, and are not equivalent to the specific embodiments described above. For those skilled in the art, making some improvements, modifications or changes to the present invention, and combining the above technical features in an appropriate manner, these improvements, modifications, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, should be regarded as the protection scope of the present invention.

[0038] It should be noted that the technical solution of the present invention may seem simple, but it is the best, most reliable, stable and environmentally friendly process for recovering low-grade copper from semi-autogenous grinding stone in copper ore concentrators so far, and it solves the technical problem that has not been successfully solved for many years in the recovery of low-grade copper from semi-autogenous grinding stone in copper ore concentrators.

Claims

1. A process for recovering low-grade copper from semi-autogenous grinding stone in a copper ore dressing plant, characterized in that The following steps are involved: S1 High Pressure Roller Mill - Screening The semi-autogenous grinding stone of the copper ore dressing plant is fed into a high-pressure roller mill for high-pressure roller grinding. After the grinding, the material is fed into a screening operation with a sieve hole size of 0.5 mm to obtain a coarse particle product with a particle size of ≥0.5 mm and a fine particle product with a particle size of <0.5 mm. S2 Screen Coarse Grain Product Heavy Medium Separation The coarse particle size product obtained in step S1 is fed into a heavy medium separation operation, wherein the heavy medium separation operation adopts a one-coarse and one-sweep process to obtain a heavy medium separation copper concentrate 1 and a heavy medium separation copper concentrate 2, respectively, and discharge the heavy medium separation and scavenging tailings; the separation equipment used in the heavy medium separation operation is a heavy medium cyclone; S3 undersize fine particle product centrifugal gravity separation The undersize fine-particle product obtained in step S1 is fed into a centrifugal gravity separation process, wherein the centrifugal gravity separation process adopts a one-roughing and one-sweeping process to obtain centrifugal gravity separation copper concentrate 3 and centrifugal gravity separation copper concentrate 4, respectively, and discharge the centrifugal gravity separation and scavenging tailings; the centrifugal gravity separation process adopts a Nelson centrifugal concentrator as the separation equipment; S4 combines the heavy medium separation copper concentrate 1 and the heavy medium separation copper concentrate 2 obtained in step S2 and the centrifugal gravity separation copper concentrate 3 and the centrifugal gravity separation copper concentrate 4 obtained in step S3 into a final copper concentrate; The heavy medium separation tailings discharged from step S2 and the centrifugal gravity separation tailings discharged from step S3 are combined into the final total tailings.

2. A process for recovering low-grade copper from semi-autogenous grinding stone in a copper ore dressing plant as claimed in claim 1, characterized in that: In step S1, the crushing particle size of the high pressure roller mill is set to 3-5 mm.

3. The process for recovering low-grade copper from semi-autogenous grinding stone in a copper ore dressing plant according to claim 1, characterized in that: In step S2, the heavy suspension used in the heavy medium separation operation is prepared from heavy medium powder and water. The heavy medium powder is made by grinding one of ferrosilicon and magnetite, and the particle size is <0.045mm and the mass content of the particle size is in the range of 80% to 90%.

4. A process for recovering low-grade copper from semi-autogenous grinding stone in a copper ore dressing plant as claimed in claim 1, 2 or 3, characterized in that: In step S3, the centrifugal force intensity of the Nelson centrifugal concentrator is controlled within the range of 40 to 70 g, and the flushing water flow rate is between 3 and 8 L / min.

5. A process for recovering low-grade copper from semi-autogenous grinding stone in a copper ore dressing plant as claimed in claim 2, characterized in that: In step S2, the heavy suspension used in the heavy medium sorting operation is prepared from heavy medium powder and water, wherein the heavy medium powder is made by grinding one of ferrosilicon and magnetite, and has a particle size of <0.045 mm and a particle mass content in the range of 80% to 90%; in step S3, the centrifugal force strength of the Nielsen centrifugal concentrator is controlled in the range of 50 to 60 g, and the flushing water flow rate is between 4 and 6 L / min.

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