A method for producing recycled copper by separating low-grade waste copper scrap

Abstract

The application discloses a method for producing regenerated copper by separating low-grade waste copper, which comprises the following steps of pretreatment, magnetic separation, vacuum cracking and post-treatment, and specifically comprises the following steps: crushing material a obtained by performing drum vibration treatment and tin removal treatment on low-grade waste copper to be treated; obtaining magnetic metal particles b and magnetic impurities c by performing magnetic separation on the material a; obtaining enriched metal particles d and impurities e by performing gravity flotation and vortex separation on the magnetic metal particles b; obtaining gaseous product f and solid residue g by performing vacuum cracking on the enriched metal particles d in a vacuum cracking furnace, and recycling the gaseous product f by condensation; obtaining regenerated anode copper by feeding the solid residue g mixed with crude copper produced by copper smelting into an anode furnace for refining and impurity removal, and obtaining anode copper plates after casting; and obtaining regenerated cathode copper and anode sludge by performing electrolytic refining on the anode copper plates, and recycling the anode sludge for precious metals.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial wear-resistant materials, and particularly relates to a method for separating and producing regenerated copper by using low-grade waste copper. BACKGROUND

[0002] With the industrialization and urbanization process, various types of waste electrical and mechanical equipment, electric wires and cables, communication tools, automobiles, household appliances and plastic packaging materials and waste materials are increasing, among which there are recyclable non-ferrous metals, precious metals and other resources, and the utilization value of rich renewable resources is even not inferior to that of original mineral resources. Compared with the development of natural mines, the development of "urban mines" is more environmentally friendly and has more economic value, which can not only save a large amount of original resources and make up for the shortage of original resources, but also recycle scarce resources and alleviate the resource and environmental contradiction. The traditional mechanical method, wet method or fire method low-grade waste copper processing technology has problems such as low efficiency, serious pollution, incomplete separation and the like, and the organic matter contained in the low-grade waste copper is easy to form dioxin and other harmful substances in the processing process. Therefore, it is of great significance to develop a method for separating and producing low-grade regenerated copper which can avoid the generation of dioxin and has high separation efficiency of valuable metals. SUMMARY

[0003] The present application mainly solves the problems of incomplete separation of impurities in the general low-grade waste copper processing method, resulting in serious pollution in the copper refining process, large amount of waste acid generated in the wet treatment of low-grade waste copper, and difficult recovery of valuable and precious metals. In order to solve the above problems, the present application provides a method for separating and producing regenerated copper by using low-grade waste copper, which uses waste circuit boards, gold-plated silver and other metal waste as raw materials, and separates small particle inorganic non-metallic impurities, dust, stains, magnetic impurities, low-density impurities, non-metallic impurities, organic impurities and the like in turn by using a multi-stage combined separation method to form regenerated crude copper with high copper content; the converter-anode furnace is used for synergistic fire refining to form high-grade regenerated anode copper, and finally the anode copper plate is made and the regenerated anode copper is prepared by electrolytic refining; the anode mud after electrolytic refining is rich in gold, silver, ruthenium, rhodium, palladium and other rare and precious metal elements, which can be further extracted by smelting process.

[0004] The present application provides a method for separating and producing regenerated copper by using low-grade waste copper.

[0005] The purpose of the present application is achieved by the method for separating and producing regenerated copper by using low-grade waste copper, which comprises pretreatment, magnetic separation, vacuum cracking and post-treatment steps, and specifically comprises:

[0006] A, pretreatment: the low-grade waste copper to be treated is crushed after being treated by a roller vibration and tin removal to obtain material a;

[0007] B. Magnetic separation: Material a is subjected to magnetic separation in a magnetic field with a strength of 0.2~0.6 Tesla to obtain magnetically separated metal particles b and magnetic impurities c;

[0008] C. Vacuum pyrolysis:

[0009] 1) The magnetically separated metal particles b are subjected to gravity flotation and eddy current separation to obtain enriched metal particles d and impurities e, which are composed of low-density impurities and non-metallic impurities;

[0010] 2) The enriched metal particles d are fed into a vacuum pyrolysis furnace for vacuum pyrolysis to obtain gaseous product f and solid residue g. The gaseous product f is recovered by condensation and can be further utilized as fuel or chemical raw material.

[0011] D. Post-processing: The solid residue g is mixed with crude copper produced by copper smelting at a mass ratio of 1: (8~12) and sent to the anode furnace for refining and impurity removal to obtain recycled anode copper. After casting, anode copper plates are obtained. The anode copper plates are electrolytically refined to obtain recycled cathode copper and anode mud. The anode mud is then used for precious metal recovery.

[0012] The specific steps are as follows:

[0013] 1) Preprocessing

[0014] First, the waste circuit boards undergo drum vibration treatment. The horizontal drum has 10mm diameter holes spaced 20mm apart on its wall for centrifugal removal of sand and gravel impurities. The drum rotates around its central axis at 100-150 rpm. The drum vibrates axially at a frequency of 60-80Hz. This step removes small particles of sand and gravel from the low-grade scrap copper, including the waste circuit boards. Afterward, the low-grade scrap copper, including the waste circuit boards, is washed with water to remove dust and stains, and then air-dried.

[0015] 2) Physical crushing

[0016] First, the waste circuit boards undergo preliminary processing to remove large electronic components such as plug-in capacitors and inductors from their surface. Next, the circuit boards are detinned at 260-280℃ to remove the solder from their surface. Then, the circuit boards are fed into a crusher for coarse crushing. A jaw crusher, with its powerful crushing capacity, can break the waste circuit boards into blocks approximately 5-10 cm in size.

[0017] The coarsely crushed circuit board blocks are then fed into a cone crusher for medium crushing, further reducing their size to 1-5 cm. Finally, an impact crusher is used for fine crushing, yielding circuit board particles with a size between 0.5-1 mm. During the crushing process, parameters such as the crusher's rotational speed and feed rate are controlled to ensure the uniformity of the crushed particles.

[0018] 3) Physical sorting

[0019] The crushed circuit board particles are then subjected to magnetic separation using a magnetic separator to remove ferromagnetic metal impurities such as iron and nickel. The magnetic field strength of the separator is adjusted according to the magnetic properties of the metal particles, typically set between 0.2 and 0.6 Tesla to ensure effective separation of ferromagnetic metals.

[0020] After magnetic separation, the metal particles are further separated by gravity separation equipment, such as a shaking table, based on the density difference between metal and non-metal particles. By adjusting parameters such as the tilt angle and water flow rate of the shaking table, metal and non-metal particles move along different trajectories on the table surface, thus achieving the enrichment of high-purity metal particles.

[0021] 4) Vacuum pyrolysis

[0022] The enriched metal particles (mainly copper and a small amount of other metals) obtained after physical sorting are fed into a vacuum pyrolysis furnace. Under vacuum conditions (vacuum level maintained at 1-10 Pa), the furnace temperature is gradually increased to 500-700℃. During this process, the organic components (such as resins and plastics) in the waste circuit boards undergo pyrolysis reactions, generating gaseous products (such as small molecule hydrocarbons like methane and ethane) and solid residues. The gaseous products are recovered through a condensation device and can be further utilized as fuel or chemical feedstock. The solid residues mainly consist of metal oxides and unreacted metal particles.

[0023] 5) Smelting process

[0024] The product from vacuum pyrolysis is mixed at a 1:10 ratio with crude copper produced by copper smelting and then fed into an anode furnace for refining. The oxidation temperature is 1180-1250℃, allowing impurities in the crude copper to readily oxidize with oxygen. Natural gas is then introduced for reduction, with the reduction temperature maintained at around 1200℃. The refined anode copper is cast into anode copper plates and then electrolytically refined in an electrolytic cell. Copper is deposited at the cathode to form cathode copper sheets with a purity greater than 99.9%, yielding a high-purity recycled copper product. Rare and precious metals such as gold and silver contained in the original scrap copper are electrolyzed to form anode sludge, which is then extracted through displacement and Kaldor furnace treatment.

[0025] The beneficial effects of this invention are as follows:

[0026] 1) High-purity recycled copper: By combining physical sorting with copper smelting processes, especially by using a combination of high-precision sorting equipment in the physical sorting stage and refining processes in the copper smelting process, impurities in waste circuit boards can be effectively removed to obtain high-purity recycled copper, which meets the needs of a variety of high-end industrial applications.

[0027] 2) Comprehensive utilization of resources: During the vacuum pyrolysis process, organic matter in waste circuit boards is effectively recycled and utilized. The generated gaseous products can be used as energy or chemical raw materials, which improves the overall resource utilization rate of the process and reduces waste emissions.

[0028] 3) Environmental friendliness: Compared to traditional chemical methods, this invention reduces the use of hazardous chemicals throughout the entire process, lowering the risk of environmental pollution. Furthermore, the vacuum pyrolysis process is conducted in a vacuum environment, reducing the emission of harmful gases and contributing to environmental protection.

[0029] 4) High recovery rate: The system processing using physical crushing, physical sorting, vacuum pyrolysis and copper smelting can maximize the recovery of copper resources in waste circuit boards, with a copper recovery rate of over 95%, which is significantly improved compared to traditional physical sorting processes. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the process flow of the present invention. Detailed Implementation

[0031] The specific embodiments of the present invention will be further described below with reference to the examples and accompanying drawings. It should be noted that these descriptions of the embodiments are for the purpose of helping to understand the present invention, but do not constitute a limitation of the present invention.

[0032] The method for producing recycled copper from low-grade scrap copper according to the present invention includes pretreatment, magnetic separation, vacuum pyrolysis, and post-treatment steps, specifically including:

[0033] A. Pre-treatment: The low-grade scrap copper to be treated is subjected to drum vibration treatment and detinning treatment, and then crushed to obtain material a;

[0034] B. Magnetic separation: Material a is subjected to magnetic separation in a magnetic field with a strength of 0.2~0.6 Tesla to obtain magnetically separated metal particles b and magnetic impurities c;

[0035] C. Vacuum pyrolysis:

[0036] 1) The magnetically separated metal particles b are subjected to gravity flotation and eddy current separation to obtain enriched metal particles d and impurities e, which are composed of low-density impurities and non-metallic impurities;

[0037] 2) The enriched metal particles d are fed into a vacuum pyrolysis furnace for vacuum pyrolysis to obtain gaseous product f and solid residue g. The gaseous product f is recovered by condensation and can be further utilized as fuel or chemical raw material.

[0038] D. Post-processing: The solid residue g is mixed with crude copper produced by copper smelting at a mass ratio of 1: (8~12) and sent to the anode furnace for refining and impurity removal to obtain recycled anode copper. After casting, anode copper plates are obtained. The anode copper plates are electrolytically refined to obtain recycled cathode copper and anode mud. The anode mud is then used for precious metal recovery.

[0039] The drum vibration treatment described in step A involves using a horizontal drum at a rotation speed of 100-150 r / min and a vibration frequency of 60-80 Hz to remove sand, dust, and stains.

[0040] The detinning process described in step A is carried out at 260~280℃.

[0041] The crushing process described in step A involves first crushing the material into blocks of 5-10cm, then feeding it into a cone crusher for medium crushing to obtain material of 1-5cm, and finally using an impact crusher for fine crushing to obtain particles with a size of 0.5-1mm.

[0042] The vacuum degree of vacuum pyrolysis described in step C (2) is 1~10 Pa.

[0043] The temperature of vacuum pyrolysis described in step 2) is 500~700℃.

[0044] The refining and impurity removal described in step D includes oxidation and reduction reactions.

[0045] The oxidation reaction is carried out at a temperature of 1180~1250℃.

[0046] The reduction reaction is carried out by introducing natural gas.

[0047] The reduction reaction is carried out at a temperature of 1100~1300℃.

[0048] The invention will be further illustrated below with specific implementation examples:

[0049] Example 1

[0050] 1. Pretreatment

[0051] 2000 kg of waste circuit boards were collected. First, the waste circuit boards underwent drum vibration treatment. They were fed into a horizontal drum machine with a set speed of 100 rpm and an axial vibration frequency of 60 Hz to remove small particles such as sand and gravel from the low-grade scrap copper. Afterward, the waste circuit boards and other low-grade scrap copper were washed with water to remove dust and stains, and then air-dried.

[0052] 2. Physical crushing

[0053] First, large electronic components are manually removed from the surface. Then, the circuit board is fed into a jaw crusher with a speed of 150 rpm and a feeding speed of 50 kg / h, and crushed into blocks of about 8 cm.

[0054] The lumps are fed into an impact crusher and crushed at a speed of 1500 rpm to obtain 1800 kg of circuit board particles with a particle size between 0.5-1 mm.

[0055] 3. Physical sorting

[0056] 1800 kg of circuit board particles were fed into a magnetic separator with a magnetic field strength of 0.3 Tesla, removing approximately 50 kg of ferromagnetic metal impurities. The remaining 1750 kg of metal particles were then subjected to gravity separation on a shaking table. The shaking table was tilted at 5° and the water flow rate was 0.5 L / s, resulting in approximately 1000 kg of enriched metal particles.

[0057] 4. Vacuum pyrolysis

[0058] 1000 kg of enriched metal particles were fed into a vacuum pyrolysis furnace, evacuated to 5 Pa, and heated to 600 °C at a rate of 10 °C / min, and held at that temperature for 2 hours. The gaseous products generated by pyrolysis were recovered through a condenser to obtain approximately 200 kg of gaseous mixture that can be used as fuel, and approximately 700 kg of solid residue.

[0059] 5. Smelting process

[0060] 700 kg of solid residue was mixed with 7000 kg of crude copper at a ratio of 1:10 and fed into an anode copper furnace for refining. The oxidation process was carried out at a temperature of 1180℃, allowing impurities in the crude copper to react smoothly with oxygen. Natural gas was then introduced for reduction, with the gas supply pressure controlled at around 7 Pa and the reduction stage temperature maintained at around 1200℃. The refined anode copper was cast into anode copper plates at 1150℃ and then fed into an electrolytic cell for electrolytic refining. Copper was deposited at the cathode to form cathode copper sheets with a purity greater than 99.9%, yielding 7500 kg of high-purity recycled copper product. Rare and precious metals such as gold and silver contained in the original scrap copper were electrolyzed to form anode mud, which was then extracted through displacement and Kaldor furnace treatment.

[0061] Example 2

[0062] 1. Pretreatment

[0063] 2000 kg of waste circuit boards were collected. First, the waste circuit boards underwent drum vibration treatment. They were fed into a horizontal drum machine with a set speed of 100 rpm and an axial vibration frequency of 60 Hz to remove small particles such as sand and gravel from the low-grade scrap copper. Afterward, the waste circuit boards and other low-grade scrap copper were washed with water to remove dust and stains, and then air-dried.

[0064] 2. Physical crushing

[0065] First, large electronic components are manually removed from the surface. Then, the circuit boards are fed into a jaw crusher at a speed of 100 rpm and a feed rate of 40 kg / h, crushing them into blocks of approximately 5 cm. These blocks are then fed into a cone crusher to be further crushed into material of approximately 3 cm, and then into an impact crusher at a speed of 1300 rpm, yielding 1700 kg of circuit board particles with a particle size between 0.5 and 1 mm.

[0066] 3. Physical sorting

[0067] 1700 kg of circuit board particles were fed into a magnetic separator with a magnetic field strength of 0.4 Tesla, removing approximately 80 kg of ferromagnetic metal impurities. The remaining 1620 kg of metal particles were then subjected to gravity separation on a shaking table. The shaking table was tilted at 7° and the water flow rate was 0.4 L / s, resulting in approximately 1120 kg of enriched metal particles.

[0068] 4. Vacuum pyrolysis

[0069] 1120 kg of enriched metal particles were fed into a vacuum pyrolysis furnace, evacuated to 8 Pa, and heated to 500 °C at a rate of 8 °C / min, and held at that temperature for 2.5 hours. The gaseous products generated by pyrolysis were recovered through a condenser to obtain approximately 220 kg of gaseous mixture that can be used as fuel, and approximately 730 kg of solid residue.

[0070] 5. Smelting process

[0071] 730 kg of solid residue was mixed with 5840 kg of crude copper at a ratio of 1:8 and fed into an anode copper furnace for refining. The oxidation process was carried out at a temperature of 1250℃, allowing impurities in the crude copper to react smoothly with oxygen. Natural gas was then introduced for reduction, with the gas supply pressure controlled at around 8 Pa and the reduction stage temperature maintained at around 1150℃. The refined anode copper was cast into anode copper plates at 1150℃ and then fed into an electrolytic cell for electrolytic refining. Copper was deposited at the cathode to form cathode copper sheets with a purity greater than 99.9%, yielding 6480 kg of high-purity recycled copper product. Rare and precious metals such as gold and silver contained in the original scrap copper were electrolyzed to form anode mud, which was then extracted through displacement and Kaldor furnace treatment.

[0072] Example 3

[0073] 1. Pretreatment

[0074] 2000 kg of waste circuit boards were collected. First, the waste circuit boards underwent drum vibration treatment. They were fed into a horizontal drum machine with a set speed of 120 rpm and an axial vibration frequency of 70 Hz to remove small particles such as sand and gravel from the low-grade scrap copper. Afterward, the waste circuit boards and other low-grade scrap copper were washed with water to remove dust and stains, and then air-dried.

[0075] 2. Physical crushing

[0076] First, large electronic components are manually removed from the surface. Then, the circuit boards are fed into a jaw crusher at a speed of 120 rpm and a feed rate of 60 kg / h, crushing them into blocks of approximately 6 cm. These blocks are then fed into a cone crusher to be further crushed into material of approximately 2 cm, and then into an impact crusher at a speed of 1600 rpm, yielding 1850 kg of circuit board particles with a particle size between 0.5 and 1 mm.

[0077] 3. Physical sorting

[0078] 1850 kg of circuit board particles were fed into a magnetic separator with a magnetic field strength of 0.5 Tesla, removing approximately 40 kg of ferromagnetic metal impurities. The remaining 1810 kg of metal particles were then subjected to gravity separation on a shaking table with the tilt angle adjusted to 4° and the water flow rate set to 0.6 L / s, yielding approximately 1450 kg of enriched metal particles.

[0079] 4. Vacuum pyrolysis

[0080] 1450 kg of enriched metal particles were fed into a vacuum pyrolysis furnace, evacuated to 4 Pa, and heated to 700 °C at a rate of 15 °C / min, and held at that temperature for 1.5 hours. The gaseous products generated by pyrolysis were recovered through a condenser to obtain approximately 320 kg of gaseous mixture that can be used as fuel, and approximately 910 kg of solid residue.

[0081] 5. Smelting process

[0082] 910 kg of solid residue was mixed with 10920 kg of crude copper at a ratio of 1:12 and fed into an anode copper furnace for refining. The oxidation process was carried out at 1200℃ to ensure that impurities in the crude copper could react smoothly with oxygen. Natural gas was then introduced for reduction, with the gas supply pressure controlled at around 6 Pa and the reduction temperature maintained at around 1300℃. The refined anode copper was cast into anode copper plates at 1200℃ and then fed into an electrolytic cell for electrolytic refining. Copper was deposited at the cathode to form cathode copper sheets with a purity greater than 99.9%, yielding 10980 kg of high-purity recycled copper product. Rare and precious metals such as gold and silver contained in the original scrap copper were formed into anode mud through electrolysis, which was then extracted through displacement and Kaldor furnace treatment.

Claims

1. A method for separating and producing recycled copper from low-grade scrap copper, characterized in that, The method for separating and producing recycled copper from low-grade scrap copper includes pretreatment, magnetic separation, vacuum pyrolysis, and post-treatment steps, specifically including: A. Pre-treatment: The low-grade scrap copper to be treated is subjected to drum vibration treatment and detinning treatment, and then crushed to obtain material a; B. Magnetic separation: Material a is subjected to magnetic separation in a magnetic field with a strength of 0.2~0.6 Tesla to obtain magnetically separated metal particles b and magnetic impurities c; C. Vacuum pyrolysis: 1) The magnetically separated metal particles b are subjected to gravity flotation and eddy current separation to obtain enriched metal particles d and impurities e, which are composed of low-density impurities and non-metallic impurities; 2) The enriched metal particles d are fed into a vacuum pyrolysis furnace for vacuum pyrolysis to obtain gaseous product f and solid residue g. The gaseous product f is recovered by condensation and further utilized as fuel or chemical raw material. D. Post-processing: The solid residue g is mixed with crude copper produced by copper smelting at a mass ratio of 1: (8~12) and sent to the anode furnace for refining and impurity removal to obtain recycled anode copper. After casting, anode copper plates are obtained. The anode copper plates are electrolytically refined to obtain recycled cathode copper and anode mud. The anode mud is used for precious metal recovery. The method for producing recycled copper from low-grade scrap copper is characterized in that the vacuum degree of the vacuum pyrolysis in step C2) is 1~10 Pa; The method for producing recycled copper from low-grade scrap copper is characterized in that the temperature of vacuum pyrolysis in step C2) is 500~700℃. The method for producing recycled copper from low-grade scrap copper is characterized in that the refining and impurity removal in step D includes oxidation and reduction reactions.

2. The method for producing recycled copper from low-grade scrap copper according to claim 1, characterized in that, The drum vibration treatment described in step A involves using a horizontal drum at a rotation speed of 100-150 r / min and a vibration frequency of 60-80 Hz to remove sand, dust, and stains.

3. The method for producing recycled copper from low-grade scrap copper according to claim 1, characterized in that, The detinning process described in step A is carried out at 260~280℃.

4. The method for producing recycled copper from low-grade scrap copper according to claim 1, characterized in that, The crushing process described in step A involves first crushing the material into blocks of 5-10cm, then feeding it into a cone crusher for medium crushing to obtain material of 1-5cm, and finally using an impact crusher for fine crushing to obtain particles with a size of 0.5-1mm.

5. The method for producing recycled copper from low-grade scrap copper according to claim 1, characterized in that, The oxidation reaction is carried out at a temperature of 1180~1250℃.

6. The method for producing recycled copper from low-grade scrap copper according to claim 1, characterized in that, The reduction reaction is carried out by introducing natural gas.

7. The method for producing recycled copper from low-grade scrap copper according to claim 1 or 6, characterized in that, The reduction reaction is carried out at a temperature of 1100~1300℃.

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