Method for producing regenerated copper by separating low-grade scrap copper

Abstract

The invention discloses a method for producing regenerated copper by separating low-grade scrap copper, which comprises the steps of pretreatment, magnetic separation, vacuum cracking and post-treatment, and specifically comprises the following steps: carrying out roller vibration treatment and detinning treatment on to-be-treated low-grade scrap copper, and crushing to obtain a material a; performing magnetic separation on the material a to obtain magnetic separation metal particles b and magnetic impurities c; the magnetic separation metal particles b are subjected to gravity flotation and vortex separation, and enriched metal particles d and impurities e are obtained; the enriched metal particles d are fed into a vacuum cracking furnace to be subjected to vacuum cracking, a gaseous product f and solid residues g are obtained, and the gaseous product f is recycled through condensation; mixing the solid residue g into crude copper produced by copper smelting, feeding the crude copper into an anode furnace for refining and impurity removal to obtain regenerated anode copper, casting to obtain an anode copper plate, performing electrolytic refining on the anode copper plate to obtain regenerated cathode copper and anode mud, and performing precious metal recovery on the anode mud.

Description

Technical Field

[0001] The invention relates to the technical field of industrial wear-resistant materials, and in particular to a method for producing recycled copper by separating low-grade scrap copper. Background Art

[0002] With the progress of industrialization and urbanization, various types of waste electromechanical equipment, wires and cables, communication tools, automobiles, home appliances, plastic packaging and waste materials are increasing, which also contain recyclable non-ferrous metals, precious metals and other resources. The utilization value of rich renewable resources is even no less than that of original mineral resources. Compared with the development of natural mines, the development of "urban mines" is more environmentally friendly and more economically valuable. It can not only save a lot of original resources and make up for the shortage of original resources, but also turn waste into treasure, recycle scarce resources and alleviate resource and environmental contradictions. The traditional mechanical, wet or pyrometallurgical low-grade scrap copper treatment process has problems such as low efficiency, high pollution and incomplete separation. The organic matter contained in low-grade scrap copper is easy to form dioxins and other harmful substances during the treatment process. Therefore, it is of great significance to develop a method for low-grade recycled copper that can avoid the generation of dioxins and has high separation efficiency of valuable metals. Summary of the invention

[0003] The present invention mainly solves the problems that the impurity separation in the general low-grade scrap copper treatment method is not thorough, resulting in large pollution in the refining and copper extraction process, large amount of waste acid generated in the low-grade scrap copper wet treatment, and difficulty in recovering valuable precious metals. In order to solve the above problems, the present invention provides a method for separating and producing recycled copper using low-grade scrap copper, using waste circuit boards, gold-plated silver and other metal wastes as raw materials, and using a multi-stage combined separation method to sequentially separate small particles of inorganic non-metallic impurities, dust, stains, magnetic impurities, low-density impurities, non-metallic impurities, organic impurities, etc., to form recycled crude copper with high copper content; using a converter-anode furnace to coordinate fire refining to form high-grade recycled anode copper, and finally making anode copper plates and preparing recycled anode copper through electrolytic refining; the anode mud after electrolytic refining is rich in rare and precious metal elements such as gold, silver, ruthenium, rhodium, palladium, etc., which can be further extracted through smelting processes.

[0004] The object of the present invention is to provide a method for producing recycled copper by separating low-grade scrap copper.

[0005] The object of the present invention is achieved in that the method for separating and producing recycled copper by using low-grade scrap copper comprises pre-treatment, magnetic separation, vacuum cracking and post-treatment steps, specifically comprising: A. Pretreatment: The low-grade scrap copper to be processed is subjected to roller vibration treatment, detinning treatment, and then crushed to obtain material a; B. Magnetic separation: Material a is subjected to magnetic separation at a magnetic field strength of 0.2-0.6 Tesla to obtain magnetically separated metal particles b and magnetic impurities c; C. Vacuum cracking: 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, wherein the impurities e are composed of low-density impurities and non-metallic impurities; 2) The enriched metal particles d are sent to a vacuum cracking furnace for vacuum cracking to obtain a gaseous product f and a solid residue g. The gaseous product f is recovered by condensation and can be further utilized as a fuel or chemical raw material; D. Post-treatment: 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 regenerated anode copper. After casting, anode copper plates are obtained. The anode copper plates are electrolytically refined to obtain regenerated cathode copper and anode mud, and the anode mud is used to recover precious metals.

[0006] The specific operations are as follows: 1) Preprocessing First, the waste circuit boards are subjected to drum vibration treatment. There are 10mm diameter holes arranged at intervals of 20mm on the wall of the horizontal drum, which are used to centrifugally discharge sand and gravel impurities. The drum rotates around the central axis at a speed of 100-150 rpm. The drum vibrates along the axial direction at a vibration frequency of 60-80Hz. This step is used to remove small particles of impurities such as sand and gravel contained in low-grade scrap copper such as waste circuit boards. After that, the low-grade scrap copper such as waste circuit boards is washed with water to remove dust and stains, and then dried naturally.

[0007] 2) Physical fragmentation First, the waste circuit boards are preliminarily processed to remove large electronic components on the surface, such as plug-in capacitors and inductors. Then the waste circuit boards are detinned at 260-280℃ to remove the solder on the surface of the circuit boards. The circuit boards are then sent to the crusher for rough crushing. The crushing equipment uses a jaw crusher, which has a strong crushing capacity and can crush the waste circuit boards into blocks of about 5-10 cm in size.

[0008] After the coarse crushing, the circuit board blocks are then sent to the cone crusher for secondary crushing, which further reduces their size to 1-5 cm. Finally, the impact crusher is used for fine crushing to obtain circuit board particles with a particle size of 0.5-1 mm. During the crushing process, the uniformity of the crushed particles is ensured by controlling the crusher's rotation speed, feed speed and other parameters.

[0009] 3) Physical sorting The crushed circuit board particles are subjected to magnetic separation by a magnetic separator to remove ferromagnetic metal impurities such as iron and nickel. The magnetic field strength of the magnetic separator is adjusted according to the magnetic properties of the metal particles, and is generally set between 0.2-0.6 Tesla to ensure the effective separation of ferromagnetic metals.

[0010] After magnetic separation, the metal particles are further separated by gravity sorting equipment, such as a shaking table, according to the density difference between metal particles and non-metal particles. By adjusting the inclination angle of the shaking table, water flow rate and other parameters, the metal particles and non-metal particles move along different trajectories on the bed surface, thus achieving the enrichment of high-purity metal particles.

[0011] 4) Vacuum pyrolysis The enriched metal particles (mainly copper and a small amount of other metals) obtained after physical sorting are sent to a vacuum cracking furnace. Under a vacuum environment (the vacuum degree is maintained at 1-10 Pa), the temperature in the furnace is gradually increased to 500-700°C. In this process, the organic components (such as resins, plastics, etc.) in the waste circuit boards will undergo cracking reactions to generate gaseous products (such as methane, ethane and other small molecular hydrocarbons) and solid residues. The gaseous products are recycled and processed through a condensation device and can be further used as fuel or chemical raw materials. The solid residues are mainly metal oxides and unreacted metal particles.

[0012] 5) Smelting treatment The product after vacuum cracking is mixed with crude copper produced by copper smelting at a ratio of 1:10 and sent to the anode furnace for refining. The oxidation temperature is 1180-1250℃, so that the impurities in the crude copper can smoothly react with oxygen for oxidation, and then natural gas is introduced for reduction. The temperature in the reduction stage is maintained at about 1200℃. The refined anode copper is cast into anode copper plates, and then enters the electrolytic cell for electrolytic refining. Copper is precipitated at the cathode to form cathode copper sheets with a purity greater than 99.9%, and a high-purity recycled copper product is obtained. The rare and precious metal elements such as gold and silver contained in the original scrap copper are electrolyzed to form anode mud, which is extracted through displacement and Kaldo furnace treatment.

[0013] The beneficial effects of the present invention are as follows: 1) High-purity recycled copper: Through the combination of physical sorting and copper smelting technology, especially the combination of a variety of high-precision sorting equipment in the physical sorting stage, and the refining process in the copper smelting process, the impurities in the waste circuit boards can be effectively removed to obtain high-purity recycled copper to meet the needs of a variety of high-end industrial applications.

[0014] 2) Comprehensive utilization of resources: During the vacuum cracking process, the organic matter in the waste circuit boards is effectively recycled and the generated gaseous products can be used as energy or chemical raw materials, which improves the comprehensive utilization rate of resources in the entire process and reduces waste emissions.

[0015] 3) Environmental protection: Compared with the traditional chemical method, the present invention reduces the use of hazardous chemicals in the entire process and reduces the risk of environmental pollution. At the same time, the vacuum cracking process is carried out in a vacuum environment, which reduces the emission of harmful gases and is beneficial to environmental protection.

[0016] 4) High recovery rate: The system treatment of physical crushing, physical sorting, vacuum cracking and copper smelting process can maximize the recovery of copper resources in waste circuit boards. The copper recovery rate can reach more than 95%, which is significantly higher than the traditional physical sorting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0018] The specific embodiments of the present invention are further described below in conjunction with the examples and drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0019] The method for producing recycled copper by separating low-grade scrap copper of the present invention comprises pre-treatment, magnetic separation, vacuum cracking and post-treatment steps, specifically comprising: A. Pretreatment: The low-grade scrap copper to be processed is subjected to roller vibration treatment, detinning treatment, and then crushed to obtain material a; B. Magnetic separation: Material a is subjected to magnetic separation at a magnetic field strength of 0.2-0.6 Tesla to obtain magnetically separated metal particles b and magnetic impurities c; C. Vacuum cracking: 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, wherein the impurities e are composed of low-density impurities and non-metallic impurities; 2) The enriched metal particles d are sent to a vacuum cracking furnace for vacuum cracking to obtain a gaseous product f and a solid residue g. The gaseous product f is recovered by condensation and can be further utilized as a fuel or chemical raw material; D. Post-treatment: 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 regenerated anode copper. After casting, anode copper plates are obtained. The anode copper plates are electrolytically refined to obtain regenerated cathode copper and anode mud, and the anode mud is used to recover precious metals.

[0020] The drum vibration treatment described in step A uses 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.

[0021] The detinning treatment described in step A is carried out at 260-280°C.

[0022] The crushing described in step A is to first crush into 5~10cm blocks, then enter the cone crusher for medium crushing to obtain 1~5cm materials, and finally use the impact crusher for fine crushing to obtain particles with a particle size of 0.5~1mm.

[0023] C. The vacuum degree of the vacuum cracking described in step 2) is 1-10 Pa.

[0024] C. The temperature of the vacuum cracking in step 2) is 500-700°C.

[0025] The refining and impurity removal in step D includes oxidation reaction and reduction reaction.

[0026] The temperature of the oxidation reaction is 1180-1250°C.

[0027] The reduction reaction is carried out by introducing natural gas.

[0028] The temperature of the reduction reaction is 1100-1300°C.

[0029] The present invention is further described below with specific implementation cases: Example 1 1. Preprocessing 2,000 kg of waste circuit boards were collected. First, the waste circuit boards were subjected to drum vibration treatment. The waste circuit boards were sent to the horizontal drum machine, and the speed was set to 100 rpm. The drum vibrated at 60 Hz in the axial direction to remove small particles of impurities such as sand and gravel contained in the waste circuit boards and other low-grade waste copper. After that, the waste circuit boards and other low-grade waste copper were washed with water to remove dust and stains, and then dried naturally.

[0030] 2. Physical crushing First, the large electronic components on the surface are removed manually, and then the circuit boards are fed into a jaw crusher with a set speed of 150 rpm and a feed rate of 50 kg / hour to break them into blocks of about 8 cm.

[0031] The lumps enter the impact crusher and are crushed at a rotation speed of 1500 rpm to obtain 1800 kg of circuit board particles with a particle size between 0.5-1 mm.

[0032] 3. Physical sorting 1800 kg of circuit board particles were fed into a magnetic separator with a magnetic field strength of 0.3 Tesla to remove about 50 kg of ferromagnetic metal impurities. The remaining 1750 kg of metal particles were gravity separated by a shaking table with the shaking table angle adjusted to 5° and the water flow rate to 0.5 L / s to obtain about 1000 kg of enriched metal particles.

[0033] 4. Vacuum pyrolysis 1000 kg of enriched metal particles were fed into a vacuum cracking furnace, evacuated to 5 Pa, heated to 600°C at a rate of 10°C / min, and kept warm for 2 hours. The gaseous products produced by cracking were recovered through a condensation device to obtain about 200 kg of gaseous mixture that can be used as fuel and about 700 kg of solid residue.

[0034] 5. Smelting treatment 700 kg of solid residue is mixed with 7000 kg of crude copper at a ratio of 1:10 and sent to the anode copper furnace for refining. The temperature of the oxidation process is 1180°C, so that the impurities in the crude copper can smoothly react with oxygen for oxidation, and then natural gas is introduced for reduction. The gas supply pressure is controlled at about 7Pa, and the temperature in the reduction stage is maintained at about 1200°C. The refined anode copper is cast into anode copper plates at 1150°C, and then enters the electrolytic cell for electrolytic refining. Copper is precipitated at the cathode to form cathode copper sheets with a purity greater than 99.9%, and 7500 kg of high-purity recycled copper products are obtained. The rare and precious metal elements such as gold and silver contained in the original scrap copper are electrolyzed to form anode mud, which is extracted through displacement and Kaldo furnace treatment.

[0035] Example 2 1. Preprocessing 2,000 kg of waste circuit boards were collected. First, the waste circuit boards were subjected to drum vibration treatment. The waste circuit boards were sent to the horizontal drum machine, and the speed was set to 100 rpm. The drum vibrated at 60 Hz in the axial direction to remove small particles of impurities such as sand and gravel contained in the waste circuit boards and other low-grade waste copper. After that, the waste circuit boards and other low-grade waste copper were washed with water to remove dust and stains, and then dried naturally.

[0036] 2. Physical crushing First, the large electronic components on the surface are manually removed, and then the circuit board is sent to the jaw crusher, set at a speed of 100 rpm and a feed rate of 40 kg / hour to break into blocks of about 5 cm. The blocks enter the cone crusher to get materials of about 3 cm, and then enter the impact crusher to break at a speed of 1300 rpm to get 1700 kg of circuit board particles with a particle size between 0.5-1 mm.

[0037] 3. Physical sorting 1700 kg of circuit board particles were fed into a magnetic separator with a magnetic field strength of 0.4 Tesla to remove about 80 kg of ferromagnetic metal impurities. The remaining 1620 kg of metal particles were gravity separated by a shaking table with the shaking table angle adjusted to 7° and the water flow rate to 0.4 L / s, yielding about 1120 kg of enriched metal particles.

[0038] 4. Vacuum pyrolysis 1120 kg of enriched metal particles were fed into a vacuum cracking furnace, evacuated to 8 Pa, heated to 500°C at a rate of 8°C / min, and kept warm for 2.5 hours. The gaseous products produced by cracking were recovered through a condensation device to obtain about 220 kg of a gaseous mixture that can be used as fuel and about 730 kg of solid residue.

[0039] 5. Smelting treatment 730 kg of solid residue was mixed with 5840 kg of crude copper at a ratio of 1:8 and sent to the anode copper furnace for refining. The temperature of the oxidation process was 1250°C, so that the impurities in the crude copper could smoothly react with oxygen for oxidation. Natural gas was then introduced for reduction. The gas supply pressure was controlled at about 8 Pa, and the temperature in the reduction stage was maintained at about 1150°C. The refined anode copper was cast into anode copper plates at 1150°C, and then entered the electrolytic cell for electrolytic refining. Copper was precipitated at the cathode to form cathode copper sheets with a purity greater than 99.9%, and 6480 kg of high-purity recycled copper products were obtained. The rare and precious metal elements such as gold and silver contained in the original scrap copper were electrolyzed to form anode mud, which was then extracted through displacement and Kaldo furnace treatment.

[0040] Example 3 1. Preprocessing 2,000 kg of waste circuit boards were collected. First, the waste circuit boards were subjected to drum vibration treatment. The waste circuit boards were sent to the horizontal drum machine, and the speed was set to 120 rpm. The drum vibrated at 70 Hz in the axial direction to remove small particles of impurities such as sand and gravel contained in the waste circuit boards and other low-grade waste copper. After that, the waste circuit boards and other low-grade waste copper were washed with water to remove dust and stains, and then dried naturally.

[0041] 2. Physical crushing First, the large electronic components on the surface are manually removed, and then the circuit board is sent to the jaw crusher, set at a speed of 120 rpm and a feed rate of 60 kg / hour to break into blocks of about 6 cm. The blocks enter the cone crusher to get materials of about 2 cm, and then enter the impact crusher to break at a speed of 1600 rpm to get 1850 kg of circuit board particles with a particle size between 0.5-1 mm.

[0042] 3. Physical sorting 1850 kg of circuit board particles were fed into a magnetic separator with a magnetic field strength of 0.5 Tesla to remove about 40 kg of ferromagnetic metal impurities. The remaining 1810 kg of metal particles were gravity separated by a shaking table with an inclination of 4° and a water flow rate of 0.6 L / s to obtain about 1450 kg of enriched metal particles.

[0043] 4. Vacuum pyrolysis 1450 kg of enriched metal particles were fed into a vacuum cracking furnace, evacuated to 4 Pa, heated to 700°C at a rate of 15°C / min, and kept warm for 1.5 hours. The gaseous products produced by cracking were recovered through a condensation device to obtain about 320 kg of a gaseous mixture that can be used as fuel and about 910 kg of solid residue.

[0044] 5. Smelting treatment 910 kg of solid residue was mixed with 10,920 kg of crude copper at a ratio of 1:12 and sent to the anode copper furnace for refining. The oxidation process temperature was 1200°C, so that the impurities in the crude copper could smoothly react with oxygen for oxidation, and then natural gas was introduced for reduction. The gas supply pressure was controlled at about 6 Pa, and the temperature in the reduction stage was maintained at about 1300°C. The refined anode copper was cast into anode copper plates at 1200°C, and then entered the electrolytic cell for electrolytic refining. Copper was precipitated at the cathode to form cathode copper sheets with a purity greater than 99.9%, and 10,980 kg of recycled copper products with higher purity were obtained. The rare and precious metal elements such as gold and silver contained in the original scrap copper were electrolyzed to form anode mud, which was extracted through displacement and Kaldo furnace treatment.

Claims

1. A method for producing recycled copper by separating low-grade scrap copper, characterized in that: The method for separating and producing recycled copper by using low-grade scrap copper includes pre-treatment, magnetic separation, vacuum cracking and post-treatment steps, specifically including: A. Pretreatment: The low-grade scrap copper to be processed is subjected to roller vibration treatment, detinning treatment, and then crushed to obtain material a; B. Magnetic separation: Material a is subjected to magnetic separation at a magnetic field strength of 0.2-0.6 Tesla to obtain magnetically separated metal particles b and magnetic impurities c; C. Vacuum cracking: 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, wherein the impurities e are composed of low-density impurities and non-metallic impurities; 2) The enriched metal particles d are sent to a vacuum cracking furnace for vacuum cracking to obtain a gaseous product f and a solid residue g. The gaseous product f is recovered by condensation and can be further utilized as a fuel or chemical raw material; D. Post-treatment: 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 regenerated anode copper. After casting, anode copper plates are obtained. The anode copper plates are electrolytically refined to obtain regenerated cathode copper and anode mud, and the anode mud is used to recover precious metals.

2. The method for producing recycled copper by separating low-grade scrap copper according to claim 1, characterized in that: The drum vibration treatment described in step A uses 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 by separating low-grade scrap copper according to claim 1, characterized in that: The detinning treatment described in step A is carried out at 260-280°C.

4. The method for producing recycled copper by separating low-grade scrap copper according to claim 1, characterized in that: The crushing described in step A is to first crush into 5~10cm blocks, then enter the cone crusher for medium crushing to obtain 1~5cm materials, and finally use the impact crusher for fine crushing to obtain particles with a particle size of 0.5~1mm.

5. The method for producing recycled copper by separating low-grade scrap copper according to claim 1, characterized in that: C. The vacuum degree of the vacuum cracking described in step 2) is 1-10 Pa.

6. The method for producing recycled copper by separating low-grade scrap copper according to claim 1, characterized in that: C. The temperature of the vacuum cracking in step 2) is 500-700°C.

7. The method for producing recycled copper by separating low-grade scrap copper according to claim 1, characterized in that: The refining and impurity removal in step D includes oxidation reaction and reduction reaction.

8. The method for producing recycled copper by separating low-grade scrap copper according to claim 7, characterized in that: The temperature of the oxidation reaction is 1180-1250°C.

9. The method for producing recycled copper by separating low-grade scrap copper according to claim 7, characterized in that: The reduction reaction is carried out by introducing natural gas.

10. The method for producing recycled copper by separating low-grade scrap copper according to claim 7 or 9, characterized in that: The temperature of the reduction reaction is 1100-1300°C.

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