A magnetic levitation combined beneficiation method for enhanced recovery of coarse and fine copper particles from copper tailings

Abstract

This invention discloses a magnetic flotation combined beneficiation method for enhanced recovery of coarse and fine copper particles from copper tailings, belonging to the field of mineral processing technology. The copper tailings are adjusted into a slurry, and 200-260 g / t of lime is added and stirred. The slurry is subjected to pulsed high-gradient magnetic separation using a 1.5 mm rod medium, a magnetic field strength of 17500-18000 Gs, and a pulse frequency of 200-350 rpm. This yields magnetic separation concentrate and magnetic separation tailings, with the middlings from the magnetic separation process incorporated into the concentrate. The tailings from the magnetic separation process are concentrated and then adjusted into a slurry, undergoing a roughing and scavenging flotation process. A modifier and collector are added to the roughing process, and a collector is added to the scavenging process. The concentrate from the scavenging process is returned to the roughing process. The concentrate from the roughing process is incorporated into the concentrate from the magnetic separation process to form a rough concentrate, and the tailings from the scavenging process are the final tailings. The rough concentrate is regrinded and subjected to flotation again. By collecting the froth product in stages, concentrate 1 and concentrate 2 are obtained. This method can enhance the recovery of copper minerals lost in wide-grained copper tailings, and achieve comprehensive resource recovery and utilization.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically relates to a magnetic levitation combined beneficiation method for enhanced recovery of coarse and fine copper particles from copper tailings. Background Technology

[0002] As a major copper importer globally, my country consumes 40% of the world's copper demand, making it highly dependent on external copper resources. With the continuous development of high-grade copper mines in China, the reserves of easily beneficiated, high-grade copper ore are gradually decreasing. The efficient development and utilization of low-grade copper ore, difficult-to-benefit copper ore, and copper tailings have become key directions for alleviating the domestic copper resource supply-demand imbalance and expanding copper resource supply channels, demonstrating broad prospects for industrial development.

[0003] Copper tailings, as a major solid waste generated during copper mining and beneficiation, require efficient and clean utilization. This is not only a core element for the non-ferrous metals industry to reduce solid waste pollution, decrease energy consumption, and implement energy conservation and emission reduction principles, but also a crucial support for promoting the industry's transformation towards green and sustainable development. Simultaneously, the research and application of efficient copper tailings separation technologies can effectively improve the recovery rate of associated copper in tailings, further unlocking resource value and providing a practical technical path for related enterprises to reduce production costs, increase product added value, and enhance economic benefits.

[0004] For large porphyry copper deposits in high-altitude areas, due to the constraints of ore properties and on-site grinding conditions, the grinding fineness of the flotation grinding process in the concentrator is approximately -0.074 mm, with about 63% of the content. This makes it difficult for copper minerals to be fully liberated, resulting in a large amount of coarse copper minerals with low liberation degree being lost into the tailings during the flotation process, causing a loss of copper metal. The effective recovery particle size range of traditional flotation machines and flotation columns is 20~150μm. When the mineral particle size exceeds 150μm, traditional flotation equipment faces a significant bottleneck in the recovery of coarse mineral particles due to factors such as turbulent pulp disturbance, high desorption probability, and limited buoyancy.

[0005] Due to the aforementioned limitations in grinding fineness and flotation particle size, the current actual tailings yield is as high as 98.45%. In the flotation tailings, the copper grade typically fluctuates between 0.05% and 0.07%, resulting in copper metal losses exceeding 5,000 tons per year, causing significant economic losses and resource waste. Therefore, developing a beneficiation method that can enhance the recovery of coarse and fine-grained copper minerals from wide-particle-size copper tailings is of significant practical importance for improving the comprehensive utilization rate of mine resources, extending the service life of mines, and promoting the construction of green mines. Summary of the Invention

[0006] The purpose of this invention is to provide a magnetic levitation combined beneficiation method for enhanced recovery of coarse and fine copper particles from copper tailings.

[0007] The objective of this invention is achieved as follows: the magnetic levitation combined beneficiation method for enhanced recovery of coarse and fine copper particles from copper tailings includes the following steps: Pretreatment: Adjust the copper tailings into a slurry and add 200~260g / t of lime and stir; Pulsating high-gradient magnetic separation: The pretreated slurry is subjected to pulsed high-gradient magnetic separation. The magnetic separation uses a 1.5mm rod medium, the magnetic field strength is set to 17500~18000Gs, and the pulse frequency is 200~350rpm; magnetic separation concentrate and magnetic separation tailings are obtained, wherein the middlings of the magnetic separation are incorporated into the magnetic separation concentrate. High-concentration flotation: After the tailings from the magnetic separation operation are concentrated and the slurry is adjusted, a roughing and a scavenging flotation operation is carried out; modifiers and collectors are added in the roughing operation, and collectors are added in the scavenging operation; the concentrate from the scavenging operation is returned to the roughing operation; the concentrate from the roughing operation is merged into the concentrate from the magnetic separation operation to become a rough concentrate, and the tailings from the scavenging operation are the final tailings product. Rough concentrate regrinding and flotation: The rough concentrate is regrinded and then subjected to flotation again. Two products, concentrate 1 and concentrate 2, are obtained by collecting the froth products in stages.

[0008] Compared with the prior art, the technical solution described in this invention has the following advantages: 1. This invention addresses the wide particle size distribution of copper tailings, which contains both coarse and fine particles. It employs a combined magnetic separation and flotation process. This process utilizes the weak magnetic properties of chalcopyrite to precisely capture coarse copper minerals exceeding the particle size limit of traditional flotation equipment through high-gradient magnetic separation, thus preventing the loss of coarse-grained resources. Furthermore, it efficiently recovers fine copper minerals through high-concentration flotation of the magnetic tailings, achieving full coverage recovery of copper minerals across all particle sizes.

[0009] 2. By using specific pulsed high-gradient magnetic separation parameters (1.5mm rod medium, magnetic field strength of 17500Gs~18000Gs, pulse frequency of 200~350rpm), the capture efficiency of coarse-grained copper minerals is improved. The magnetization force generated by the high gradient can promote magnetic flocculation or magnetic chaining of weakly magnetic copper-bearing intergrowths; the 1.5mm rod medium is a coarse medium, and when coarse-grained copper-bearing intergrowths pass through the medium pile with the slurry, their large inertia can form eddy current collisions and mechanical interception on the rod surface, improving the capture efficiency; in addition, the pulsed fluid force is used to overcome the adhesive force between gangue and copper minerals, which can effectively disperse the gangue flocs of lean intergrowths; incorporating the magnetically separated ore into the concentrate further improves the recovery rate of magnetic separation.

[0010] 3. The high-concentration flotation stage employs a customized reagent system (a composite modifier of lime and sodium thiosulfate, and a composite collector of hydrocarbon dithiophosphate sulfide esters and emulsified kerosene), enhancing the collection effect on fine-grained copper minerals. The composite modifier has a certain reducing and cleaning effect on the fresh mineral surface exposed after magnetic separation, removing the surface coating layer generated by the strong magnetic field and shear force during high-gradient magnetic separation, thus restoring the floatability of copper minerals. The composite collector has a strong chemical adsorption effect on fine-grained copper minerals and can produce physical adhesion for coarse-grained copper minerals, compensating for the poor adaptability of single reagents to a wide particle size range.

[0011] 4. Subsequent rough concentrate regrinding and flotation operations achieve selective interface liberation of intergrowths by precisely controlling the grinding fineness, which further optimizes the concentrate quality. The product structure is adjusted by using segmented froth product collection. Finally, the two concentrate products are returned to the original flotation process according to the principle of similar grade, which greatly improves the comprehensive utilization rate of mineral resources.

[0012] In summary, this invention provides a magnetic flotation combined beneficiation method for enhanced recovery of coarse and fine-grained copper minerals from wide-grained copper tailings. The proposed method utilizes a specific high-gradient magnetic separation process combined with a specific flotation reagent system and flotation process to enhance the recovery of copper minerals lost in the tailings, achieving comprehensive resource recovery and utilization. Attached Figure Description

[0013] Figure 1 This is a process flow diagram of the magnetic levitation combined mineral processing method described in this invention. Detailed Implementation

[0014] The present invention will be further described below, but this is not intended to limit the invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the scope of protection of the present invention.

[0015] The magnetic levitation combined beneficiation method for enhanced recovery of coarse and fine copper particles from copper tailings according to the present invention includes the following steps: Pretreatment: Adjust the copper tailings into a slurry and add 200~260g / t of lime and stir; Pulsating high-gradient magnetic separation: The pretreated slurry is subjected to pulsed high-gradient magnetic separation. The magnetic separation uses a 1.5mm rod medium, the magnetic field strength is 17500~18000Gs, and the pulse frequency is 200~350rpm; magnetic separation concentrate and magnetic separation tailings are obtained, wherein the middlings of the magnetic separation are incorporated into the magnetic separation concentrate. High-concentration flotation: After the tailings from the magnetic separation operation are concentrated and the slurry is adjusted, a roughing and a scavenging flotation operation is carried out; modifiers and collectors are added in the roughing operation, and collectors are added in the scavenging operation; the concentrate from the scavenging operation is returned to the roughing operation; the concentrate from the roughing operation is merged into the concentrate from the magnetic separation operation to become a rough concentrate, and the tailings from the scavenging operation are the final tailings product. Rough concentrate regrinding and flotation: The rough concentrate is regrinded and then subjected to flotation again. Two products, concentrate 1 and concentrate 2, are obtained by collecting the froth products in stages.

[0016] In the pretreatment process, the slurry concentration is 18-25%; the stirring time is 5-8 minutes.

[0017] In the pulsating high-gradient magnetic separation process, the magnetic field strength is preferably 18000 Gs, the pulsation frequency is preferably 220 rpm, and the slurry flow rate during magnetic separation is 3~5 L / min.

[0018] In the high-concentration flotation process, the pulp concentration is 35-45%; the modifier is composed of lime and sodium thiosulfate in a mass ratio of 1:1-2:1; the dosage is 100-180 g / t; the collector is a mixture of hydrocarbon dithiophosphate thioether esters, emulsified kerosene, and alcohol solvents, wherein the hydrocarbon dithiophosphate thioether esters are 65-85 parts, the emulsified kerosene is 20-24 parts, and the alcohol solvent is 8-12 parts; the dosage for roughing is 20-35 g / t, and for scavenging is 8-12 g / t.

[0019] In the regrinding and flotation process of the rough concentrate, the grinding fineness of the regrinding is controlled to be -0.047mm, accounting for 80.3~82.4%.

[0020] Example 1

[0021] In this embodiment, the ore selected is the tailings after mixed flotation of a large porphyry copper mine in Yunnan. The tailings contain 0.065% copper, and particle size analysis shows that the content of particles larger than 150μm in the tailings is 10.72%.

[0022] A small-scale continuous beneficiation test was conducted using the magnetic levitation combined mineral processing method described in this invention, comprising the following steps: Pretreatment: Adjust the copper tailings to a 20% concentration slurry, add 220g / t of lime and stir for 6 minutes. Pulsating high-gradient magnetic separation: The pretreated slurry is subjected to pulsating high-gradient magnetic separation using a 1.5mm rod medium, with a magnetic field strength of 18000Gs, a pulsation frequency of 220rpm, and a slurry flow rate of 4L / min. The results are magnetic concentrate and non-magnetic tailings, with the middlings from the magnetic separation process incorporated into the magnetic concentrate.

[0023] High-concentration flotation: After the tailings from the magnetic separation operation are concentrated and the slurry is adjusted to a concentration of 43%, a high-concentration roughing and scavenging flotation operation is carried out. A modifier and a collector are added to the roughing operation, and a collector is added to the scavenging operation. The concentrate from the scavenging operation is returned to the roughing operation. The concentrate from the roughing operation is merged into the concentrate from the magnetic separation operation to become a rough concentrate, and the tailings from the scavenging operation are the final tailings product.

[0024] The modifier is composed of lime and sodium thiosulfate in a mass ratio of 1.6:1; the dosage is 115 g / t; the collector is a mixture of hydrocarbon dithiophosphate thioether esters, emulsified kerosene, and alcohol solvents, of which 68 parts are hydrocarbon dithiophosphate thioether esters, 22 parts are emulsified kerosene, and 10 parts are alcohol solvents; the dosage for roughing operation is 25 g / t, and the dosage for scavenging operation is 10 g / t.

[0025] Rough concentrate regrinding and flotation: The rough concentrate is fed into a ball mill for regrinding, and the grinding fineness is controlled to be -0.047mm, accounting for 81.5%. Flotation is carried out again, and two products, concentrate 1 and concentrate 2, are obtained by collecting the froth products in stages.

[0026] Example 2

[0027] The ore selected in this embodiment is the same as in Embodiment 1.

[0028] A small-scale continuous beneficiation test was conducted using the magnetic levitation combined mineral processing method described in this invention, comprising the following steps: Pretreatment: Adjust the copper tailings to a slurry concentration of 25%, add 250g / t of lime and stir for 8 minutes.

[0029] Pulsating high-gradient magnetic separation: The pretreated slurry is subjected to pulsating high-gradient magnetic separation using a 1.5mm rod medium, with a magnetic field strength of 17500Gs, a pulsation frequency of 350rpm, and a slurry flow rate of 3L / min. The results are magnetic concentrate and non-magnetic tailings, with the middlings from the magnetic separation process incorporated into the magnetic concentrate.

[0030] High-concentration flotation: After the tailings from the magnetic separation operation are concentrated and the slurry is adjusted to a concentration of 35%, a high-concentration roughing and scavenging flotation operation is carried out. A modifier and a collector are added to the roughing operation, and a collector is added to the scavenging operation. The concentrate from the scavenging operation is returned to the roughing operation. The concentrate from the roughing operation is merged into the concentrate from the magnetic separation operation to become a rough concentrate, and the tailings from the scavenging operation are the final tailings product.

[0031] The modifier is composed of lime and sodium thiosulfate in a mass ratio of 1:1; the dosage is 175 g / t; the collector is a mixture of hydrocarbon dithiophosphate sulfide esters, emulsified kerosene, and alcohol solvents, wherein the hydrocarbon dithiophosphate sulfide esters are 80 parts, the emulsified kerosene is 24 parts, and the alcohol solvent is 12 parts; the dosage for roughing operation is 32 g / t, and the dosage for scavenging operation is 12 g / t.

[0032] Rough concentrate regrinding and flotation: The rough concentrate is fed into a ball mill for regrinding, and the grinding fineness is controlled to be -0.047mm, accounting for 82.1%. Flotation is carried out again, and two products, concentrate 1 and concentrate 2, are obtained by collecting the froth products in stages.

[0033] Example 3

[0034] The ore selected in this embodiment is the same as in Embodiment 1.

[0035] A small-scale continuous beneficiation test was conducted using the magnetic levitation combined mineral processing method described in this invention, comprising the following steps: Pretreatment: Adjust the copper tailings to a slurry concentration of 18%, add 200g / t of lime and stir for 5 minutes.

[0036] Pulsating high-gradient magnetic separation: The pretreated slurry is subjected to pulsating high-gradient magnetic separation using a 1.5mm rod medium, with a magnetic field strength of 18000Gs, a pulsation frequency of 300rpm, and a slurry flow rate of 5L / min. The resulting concentrate (magnetic concentrate) and tailings (non-magnetic tailings) are obtained, with the middlings from the magnetic separation process incorporated into the concentrate.

[0037] High-concentration flotation: After the tailings from the magnetic separation operation are concentrated and the slurry is adjusted to a concentration of 40%, a high-concentration roughing and scavenging flotation operation is carried out. A modifier and a collector are added to the roughing operation, and a collector is added to the scavenging operation. The concentrate from the scavenging operation is returned to the roughing operation. The concentrate from the roughing operation is merged into the concentrate from the magnetic separation operation to become a rough concentrate, and the tailings from the scavenging operation are the final tailings product.

[0038] The modifier is composed of lime and sodium thiosulfate in a mass ratio of 2:1; the dosage is 100g / t; the collector is a mixture of hydrocarbon dithiophosphate thioether esters, emulsified kerosene, and alcohol solvents, wherein the hydrocarbon dithiophosphate thioether esters are 70 parts, the emulsified kerosene is 20 parts, and the alcohol solvent is 8 parts; the dosage for roughing operation is 20g / t, and the dosage for scavenging operation is 8g / t.

[0039] Rough concentrate regrinding and flotation: The rough concentrate is fed into a ball mill for regrinding, and the grinding fineness is controlled to be -0.047mm, accounting for 80.7%. Flotation is carried out again, and two products, concentrate 1 and concentrate 2, are obtained by collecting the froth products in stages.

[0040] Example 4

[0041] —Comparative Example The ore selected in this comparative example is the same as that in Example 1.

[0042] The difference between this mineral processing method and the one of the present invention is that it does not use a high-gradient magnetic separation process, but uses a traditional "one roughing, one concentrate regrinding, one finishing, one scavenging" process, the specific steps of which are as follows: After the tailings are concentrated, the slurry is adjusted to a concentration of 43% for high-concentration roughing flotation. A modifier and a collector are added during the roughing operation. The modifier is composed of lime and sodium thiosulfate in a mass ratio of 1.6:1, with a dosage of 200 g / t. The collector is a mixture of hydrocarbon dithiophosphate thioether esters, emulsified kerosene, and alcohol solvents, with 68 parts hydrocarbon dithiophosphate thioether esters, 22 parts emulsified kerosene, and 10 parts alcohol solvents, with a dosage of 35 g / t.

[0043] The tailings from the roughing process enter a primary scavenging process, where a collector of 20 g / t is added. The collector is a mixture of hydrocarbon dithiophosphate sulfide esters, emulsified kerosene, and alcohol solvents, comprising 68 parts hydrocarbon dithiophosphate sulfide esters, 22 parts emulsified kerosene, and 10 parts alcohol solvent. The concentrate obtained from the scavenging process is returned to the roughing process, and the resulting tailings are the final tailings.

[0044] The concentrate from the roughing process is regrinded in a ball mill, with the grinding fineness controlled at -0.047mm (81.5%). Then, a cleaning process is performed, and the tailings from the cleaning process are returned to the roughing process. The resulting concentrate is the final concentrate product.

[0045] Table 1 Comparison of indicators between Example 1 and the comparative example

[0046]

[0047] Table 2 Comparison of particle size distribution of final tailings after separation in Example 1 and the comparative example. As can be seen from the comparison in Table 1, according to the process flow and reagent system of the present invention, the copper grade of the obtained concentrate 1 increases by 3.17% compared with that of single high-concentration flotation. It can be directly used as the rough concentrate of the original mixed flotation process and enter the cleaning operation. The tailings grade is reduced from 0.065% to 0.042%, effectively recovering copper minerals in the tailings. Based on the original process tailings yield of 98%, the tailings discharge can be reduced by 1.58%.

[0048] As can be seen from the comparison in Table 2, according to the process flow of the present invention, coarse-grained copper minerals in the tailings are effectively recovered.

Claims

1. A method for enhanced recovery of coarse and fine particles of copper from copper tailings by magnetic levitation combined beneficiation, characterized in that, The process comprises the following steps: Pre-treatment: adjust the copper tailings into a slurry, add lime 200-260 g / t and stir; Pulsating high gradient magnetic separation: the pre-treated slurry is subjected to pulsating high gradient magnetic separation, the magnetic separation uses 1.5 mm rod medium, the magnetic field strength is 17500-18000 Gs, and the pulsating pulse frequency is 200-350 rpm; a magnetic separation operation concentrate and a magnetic separation operation tailings are obtained, wherein the middlings in the magnetic separation operation are combined into the magnetic separation concentrate; High concentration flotation: the magnetic separation operation tailings are concentrated and then adjusted into a slurry, and a one-roughing-one-scavenging flotation operation is performed; the roughing operation adds an adjusting agent and a collector, and the scavenging operation adds a collector; the concentrate of the scavenging operation is returned to the roughing operation; the concentrate of the roughing operation is combined into the magnetic separation concentrate to become a rough concentrate, and the tailings of the scavenging operation are the final tailings product; Rough concentrate regrinding flotation: the rough concentrate is regrinded and then subjected to a flotation operation again, and two products, a concentrate 1 and a concentrate 2, are obtained by segmentally collecting the froth products.

2. The magnetic levitation combined beneficiation method according to claim 1, characterized in that, In the pre-treatment process, the slurry concentration is 18-25%.

3. The magnetic levitation combined beneficiation method according to claim 1, characterized in that, In the pre-treatment process, the stirring time is 5-8 min.

4. The magnetic levitation combined beneficiation method according to claim 1, characterized in that, In the pulsating high gradient magnetic separation process, the magnetic field strength of the magnetic separation is 18000 Gs, and the pulsating pulse frequency is 220 rpm.

5. The magnetic levitation combined beneficiation method according to claim 1, characterized in that, In the pulsating high gradient magnetic separation process, the slurry flow rate during the magnetic separation is 3-5 L / min.

6. The magnetic levitation combined beneficiation method according to claim 1, characterized in that, In the high concentration flotation process, the adjusted slurry concentration is 35-45%.

7. The magnetic levitation combined beneficiation method according to claim 1, characterized in that, In the high concentration flotation process, the adjusting agent is composed of lime and sodium thiosulfate in a mass ratio of 1:1-2:1; the amount used is 100-180 g / t.

8. The magnetic levitation combined beneficiation method according to claim 1, characterized in that, In the high concentration flotation process, the collector is a mixture of hydrocarbyl dithiophosphoric sulfide ester, emulsified kerosene and alcohol solvent, wherein the hydrocarbyl dithiophosphoric sulfide ester is 65-85 parts, the emulsified kerosene is 20-24 parts, and the alcohol solvent is 8-12 parts; the amount used in the roughing operation is 20-35 g / t, and the amount used in the scavenging operation is 8-12 g / t.

9. The magnetic levitation combined beneficiation method according to claim 1, characterized in that, In the rough concentrate regrinding flotation process, the grinding fineness of the regrinding is controlled to be 80.3-82.4% of -0.047 mm.

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