Recycled copper, waste copper regeneration method, low-oxygen copper bar and preparation method and application of low-oxygen copper bar

Abstract

The invention belongs to the technical field of waste copper recovery, and particularly relates to regenerated copper, a waste copper regeneration method, a low-oxygen copper bar and a preparation method and application of the low-oxygen copper bar. The waste copper regeneration method comprises the following steps that after waste copper is subjected to impurity removal through a sulfuric acid solution, solids are taken and mixed with nitric acid, and a mixed solution is obtained; the mixed solution is mixed with a copper masking agent and then mixed with an impurity complexing agent; adding an oxidizing agent into the filtrate, and mixing with a copper complexing agent; and the precipitate is taken to be subjected to reduction treatment, and regenerated copper is obtained. According to the waste copper regeneration method provided by the invention, the prepared regenerated copper is high in purity, high in recovery rate and low in oxygen content.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of waste copper recycling, and particularly relates to a method for recycling copper and waste copper, a low-oxygen copper bar and a preparation method and application thereof. BACKGROUND

[0002] Waste copper mainly includes new waste copper and old waste copper. The new waste copper is waste generated in the production, processing and manufacturing process of copper and copper alloy products. The old waste copper refers to copper materials after use, which is the main source of waste copper resources. The main sources of old waste copper include buildings and power facilities, electronics and electrical appliances, industrial equipment, transportation and other daily consumer goods (such as ornaments, musical instruments, hardware, etc.).

[0003] New waste copper is usually clear in composition, clean and easy to recycle, and most of it will be directly recycled in the production system. However, old waste copper is more difficult to recycle because it is mixed with more impurities after use. In particular, low-grade waste copper (copper content below 85%) has a large annual output, but due to the scattered sources of waste copper and the existing complex recovery process, high recovery cost and low economic value, the recovery of low-grade waste copper is still a technical difficulty in recycling copper. SUMMARY

[0004] To solve the above problems, the application provides a method for recycling copper and waste copper, a low-oxygen copper bar and a preparation method and application thereof, to solve at least one aspect of the above technical problems.

[0005] The application is achieved by the following technical solutions: In a first aspect, the application provides a method for recycling waste copper, comprising the following steps: After the waste copper is impurity-removed by a sulfuric acid solution, the solid is mixed with nitric acid to obtain a mixed solution; The mixed solution is mixed with a copper masking agent and then mixed with an impurity complexing agent; The filtrate is added with an oxidizing agent and mixed with a copper complexing agent; The precipitate is subjected to reduction treatment to obtain recycled copper.

[0006] In a second aspect, the application provides recycled copper obtained by the above method for recycling waste copper.

[0007] In a third aspect, the application provides a low-oxygen copper bar, and the raw material comprises the recycled copper.

[0008] In a fourth aspect, the application provides a preparation method of the above low-oxygen copper bar, comprising the following steps: The recycled copper is made into a copper bar matrix.

[0009] The method for recycling waste copper provided by the application has at least the following beneficial technical effects compared with the prior art: The waste copper regeneration method has high purity (more than 99.3%) of the regenerated copper, high recovery rate (more than 98.5%) and low oxygen content (less than 30 ppm).

[0010] Compared with the prior art, the low-oxygen copper bar has at least the following beneficial technical effects: The low-oxygen copper bar has a tensile strength of more than 453 MPa and an electrical conductivity of more than 100% IACS. DETAILED DESCRIPTION

[0011] In order to make the objectives, technical solutions and advantages of the present application clearer, the following describes and explains the present application in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. Based on the embodiments provided by the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0012] Obviously, the following description is only some examples or embodiments of the present application, and for those of ordinary skill in the art, the present application can also be applied to other similar scenarios without creative labor. In addition, it can be understood that although the efforts made in this development process can be complex and lengthy, for those of ordinary skill in the art related to the disclosed content of the present application, some designs, manufacturing or production changes based on the technical content disclosed in the present application are only routine technical means, and should not be understood as insufficient disclosure of the present application.

[0013] However, there may be cases of omitting unnecessary detailed description. For example, there are cases of omitting detailed description of well-known matters, repeated description of practically identical structures. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the following description is provided to enable those skilled in the art to fully understand the present application and is not intended to limit the subject matter recited in the claims.

[0014] If not specifically stated, all embodiments and optional embodiments of the present application can be combined to form new technical solutions, and all technical features and optional technical features of the present application can be combined to form new technical solutions.

[0015] The waste copper recycling method mainly includes two categories: pyrometallurgy and electrolytic refining. The pyrometallurgy can be used for smelting waste copper with extremely low grade to high grade, but for waste copper with low grade and below, the pyrometallurgy will produce a large amount of slag, so that the copper recovery rate is low; in addition, if the waste copper contains nickel, it is difficult to separate the nickel from copper through the pyrometallurgy, so that the purity of the recycled copper is reduced. The electrolytic refining can significantly improve the purity of copper, but it can only refine high-grade waste copper with copper content of 96.5% or above, so that the application range is narrow, the energy consumption is high, the equipment investment is large and the production cycle is long, and it is not suitable for recycling of a large amount of low-grade waste copper.

[0016] In order to realize effective recycling and effective utilization of low-grade waste copper, the embodiments of the present application provide a waste copper recycling method, a low-oxygen copper row and a preparation method and application thereof. The characteristics of the main ion components in the waste copper are utilized, the impurities are removed first, then the copper is reduced, and finally the high-purity oxygen-free copper is obtained, and the oxygen-free copper row is made, so that the low-grade waste copper resources are widely and effectively utilized.

[0017] The following is a detailed description of a waste copper recycling method, a low-oxygen copper row and a preparation method and application thereof according to the embodiments of the present application.

[0018] The first aspect of the embodiments of the present application provides a waste copper recycling method, which comprises the following steps: S10. After the waste copper is impurity-removed by a sulfuric acid solution, the solid is mixed with nitric acid to obtain a mixed solution.

[0019] S20. After the mixed solution is mixed with a copper masking agent, the copper masking agent is mixed with an impurity complexing agent.

[0020] S30. The filtrate is mixed with an oxidizing agent, and then mixed with a copper complexing agent.

[0021] S40. The precipitate is subjected to reduction treatment to obtain recycled copper.

[0022] The waste copper recycling method provided by the embodiments of the present application is as follows: the waste copper is impurity-removed by a sulfuric acid solution to remove the metals (such as iron, magnesium and aluminum) which are more active than copper and dissolved in sulfuric acid; then the waste copper is mixed with nitric acid to dissolve copper; after the copper ions are masked by a copper masking agent, an impurity complexing agent is added for further removal of impurity ions; after the oxidizing agent is added to the solution, the copper ions are released, and then the copper complexing agent is mixed to make the copper precipitate in the form of a complex; and the precipitate is subjected to reduction treatment to obtain recycled copper. The elemental copper obtained by the waste copper recycling method provided by the embodiments of the present application has high purity, high recovery rate and low oxygen content.

[0023] In some embodiments, in the above step S10, the copper content in the waste copper is 85% or less.

[0024] In some embodiments, in the above step S10, the particle size D50 of the waste copper is 1mm-10mm.

[0025] In some embodiments, in the step S10, the solid-liquid ratio of the waste copper and the sulfuric acid is 1: (2-3).

[0026] In some embodiments, in the step S10, the concentration of the sulfuric acid solution is 0.5-1 mol / L.

[0027] In some embodiments, in the step S10, the impurity removal of the sulfuric acid solution includes the following steps: S101. The waste copper is placed in the sulfuric acid solution for constant temperature impurity removal under mechanical stirring.

[0028] In some embodiments, in the step S101, the rotating speed of the mechanical stirring is 100-300 rpm.

[0029] In some embodiments, in the step S101, the temperature of the constant temperature impurity removal is 25-35℃. In this case, the reaction between the active metals in the waste copper and the sulfuric acid is an exothermic reaction, which increases the temperature of the reaction system. The increased temperature will lead to the instability of the reaction system and may cause the reaction of part of the copper. It should be noted that the time of the constant temperature impurity removal can be adjusted according to the actual production situation. The time is increased when the impurity content is high. However, the time of the constant temperature impurity removal in the embodiments of the present application is not particularly limited and is 0.5-1 h for illustration.

[0030] In some embodiments, in the step S10, the solid material includes the following steps: S102. The reaction system after the impurity removal by the sulfuric acid solution is filtered, washed and dried to a constant weight.

[0031] In some embodiments, in the step S102, the filtering mode includes suction filtration.

[0032] In some embodiments, in the step S102, the washing includes the following steps: S1021. The filter residue after the filtration is washed with water until the water is neutral.

[0033] In some embodiments, in the step S102, the drying temperature is 80-100℃.

[0034] In some embodiments, in the step S10, the concentration of the nitric acid is 4-8 mol / L.

[0035] In some embodiments, in the step S10, the mixing of the solid material and the nitric acid includes the following steps: S103. The solid material is mixed with the nitric acid under mechanical stirring and constant temperature to obtain a mixed solution.

[0036] The solid is mixed with nitric acid, mechanical stirring promotes the dissolution of the solid, constant temperature can make the reaction of the solid and nitric acid constant, which ensures the dissolution rate of copper and the safety of the reaction system. It should be noted that the amount of nitric acid can be adjusted according to the actual production, and the amount of nitric acid is generally excessive, so that the copper in the solid can be completely dissolved.

[0037] In some embodiments, in the above step S103, the rotating speed of mechanical stirring is 100 rpm-300 rpm.

[0038] In some embodiments, in the above step S103, the constant temperature is 15℃-25℃.

[0039] In some embodiments, in the above step S20, the copper masking agent includes sodium thiosulfate.

[0040] In some embodiments, in the above step S20, mixing the mixed solution with the copper masking agent includes the following steps: S201. After adjusting the pH value of the mixed solution to 7-9, mix with the copper masking agent.

[0041] In the above mixing of the mixed solution with the copper masking agent, the pH value of the mixed solution is adjusted to 7-9, so that the copper ions and the copper masking agent fully react to form a soluble copper complex. It should be noted that the amount of copper masking agent can be adjusted according to the actual production, and generally needs to be excessive, and the color of the reaction end solution is generally dark brown purple.

[0042] In some embodiments, in the above step S20, the impurity complexing agent includes A component and B component; The A component includes hydroxyethylidene diphosphonic acid ethyl ester; The B component includes dimethylglyoxime reagent.

[0043] In the above impurity complexing agent, the A component can remove the residual calcium ions, magnesium ions and other impurity metal ions in the mixed solution, and the hydroxyethylidene diphosphonic acid ethyl ester can slow down the coordination reaction rate of calcium ions and magnesium ions, thereby reducing the occurrence of side reactions; The dimethylglyoxime contained in the B component can specifically remove the nickel ions similar to copper, reducing the impurities brought out by subsequent copper precipitation.

[0044] In some embodiments, the preparation of hydroxyethylidene diphosphonic acid ethyl ester includes the following steps: Under the protection of inert gas, hydroxyethylidene diphosphonic acid (HEDP) is mixed with excess triethyl phosphite and then refluxed.

[0045] In the above preparation of hydroxyethylidene diphosphonic acid ethyl ester, the inert protective gas can prevent the reaction from contacting with water, which causes the hydrolysis of triethyl phosphite. The main reaction of the reflux reaction is: HEDP+4(C2H 50)3P→(C2H5O)2P(O)-C(OH)(CH3)-P(O)(OC2H5)2+4C2H5OH, during the reflux reaction, ethanol will be evaporated as a byproduct. The evaporated ethanol can be collected by a fractionating column, which also helps to move the reaction equilibrium to the right and improve the yield.

[0046] In some embodiments, the inert protective gas comprises at least one of helium, argon, and nitrogen.

[0047] In some embodiments, the reflux reaction temperature is 120-140°C. It should be noted that the reflux reaction time is determined by the end of the reaction, which can be adjusted according to the actual preparation, and is not particularly limited in the embodiments of the present application. The end of the reaction is generally when the amount of ethanol distillate reaches or approaches the theoretical calculated amount, i.e., 4 mol of ethanol should be generated when 1 mol of HEDP is completely reacted. When the amount of distillate reaches more than 90% of the theoretical value, and there is no new distillate in unit time, the reaction is considered to be complete.

[0048] In some embodiments, the preparation of ethyl hydroxyethylidene diphosphonate further comprises the following steps: The crude product is obtained and subjected to high-vacuum distillation to obtain ethyl hydroxyethylidene diphosphonate.

[0049] In some embodiments, the step of obtaining the crude product comprises removing excess triethyl phosphite and residual ethanol by vacuum distillation.

[0050] In some embodiments, the butanedione oxime reagent comprises the following components by mass fraction: Butanedione oxime 0.5%-1%, and the balance is ethanol.

[0051] In some embodiments, in the above step S20, the mixing with the impurity complexing agent comprises the following steps: S202. The pH value is maintained at 7-9, and after mixing with component A, the filtrate is mixed with component B.

[0052] In the step of mixing the above mixture with the impurity complexing agent, the pH value is maintained at 7-9 to stabilize the copper complex in the solution, and then the impurity complexing agent is mixed to precipitate the impurity ions. It should be noted that the amount of impurity complexing agent can be adjusted according to the actual production conditions, and generally needs to be excessive to make the impurity ions precipitate as completely as possible. The end of the reaction is generally when no more precipitate is precipitated.

[0053] In some embodiments, in the above step S30, the oxidizing agent comprises ozone. In this case, the oxidation ability of ozone is extremely strong, which can completely destroy the complex and will not introduce new impurities. The reaction byproduct of oxygen and copper sodium thiosulfate is O2 and SO4 2-It should be noted that the amount of oxidizing agent can be adjusted according to the actual production situation, and generally needs to be excessive to completely dissociate copper ions from the complex.

[0054] In some embodiments, in the step S30 described above, the copper complexing agent comprises a precipitant and a flocculant.

[0055] In some embodiments, the precipitant comprises zinc dimethyl dithiocarbamate.

[0056] In some embodiments, the CAS number of zinc dimethyl dithiocarbamate is 137-30-4.

[0057] In some embodiments, the flocculant comprises polydimethyl diallyl ammonium chloride.

[0058] In some embodiments, the CAS number of polydimethyl diallyl ammonium chloride is 26062-79-3.

[0059] In some embodiments, in the step S30 described above, the mixing with the copper complexing agent comprises the following steps: S301. Adjust the pH value to 4.0-6.0, mix and stir the filtrate after oxidation by the oxidizing agent and the precipitant, and then add the flocculant and continue stirring.

[0060] In some embodiments, in the step S301 described above, sulfuric acid is used to adjust the pH value of the filtrate.

[0061] In some embodiments, in the step S301 described above, the stirring speed of mixing and stirring is 150-200 rpm.

[0062] In some embodiments, in the step S301 described above, the mixing and stirring time is 15-30 min.

[0063] In some embodiments, in the step S301 described above, the continued stirring comprises the following steps: S3011. After stirring at a stirring speed of 150-200 rpm for 2-5 min, adjust the stirring speed to 30-40 rpm and stir for 10-20 min.

[0064] In the above continued stirring, stirring at a stirring speed of 150-200 rpm can promote uniform dispersion of the flocculant; adjusting the stirring speed to 30-40 rpm promotes the growth of alum flowers.

[0065] In some embodiments, in the step S40 described above, the reduction treatment comprises the following steps: S401. After removing impurities from the precipitate, calcine it in a reducing atmosphere.

[0066] In the above reduction treatment, the precipitate is doped, the excess water, nitrate, sulfate, zinc ions and other impurities in the precipitate are removed, and then the copper compound is reduced to elemental copper under a reducing atmosphere.

[0067] In some embodiments, in the above step S401, the doping of the precipitate includes the following steps: S4011. The precipitate is washed with water and then dried at 100-150 DEG C to constant weight.

[0068] In the above doping of the precipitate, the precipitate is washed with water to remove the nitrate, sulfate, zinc ions and other impurities, and then dried at 100-150 DEG C to remove the water.

[0069] In some embodiments, in the above step S401, the reducing atmosphere includes a mixture of hydrogen and helium. In some embodiments, the volume ratio of hydrogen to helium in the mixture is 1: (2-5). In this case, the hydrogen concentration is low and does not contact with oxygen, reducing the risk of hydrogen reduction.

[0070] In some embodiments, in the above step S401, the calcination includes the following steps: S4012. After the first holding at 200-300 DEG C, the temperature is raised to 400-600 DEG C for the second holding.

[0071] In the above calcination, the first holding is performed at 200-300 DEG C. The residual water and solvent in the precipitate are removed, and the preliminary decomposition of the organic matter begins; the second holding is performed at 400-600 DEG C to crack the precipitate and reduce the copper.

[0072] In some embodiments, in the above step S4012, the temperature raising rate to 200-300 DEG C is 5-10 DEG C / min.

[0073] In some embodiments, in the above step S4012, the first holding time is 30-60 min.

[0074] In some embodiments, in the above step S4012, the temperature raising rate to 400-600 DEG C is 5-10 DEG C / min.

[0075] In some embodiments, in the above step S4012, the second holding time is 60-120 min.

[0076] The second aspect of the embodiments of the present application provides a low-oxygen copper bar, which is prepared from the regenerated copper prepared by the above waste copper regeneration method.

[0077] The low-oxygen copper bar provided by the embodiment of the present application contains the regenerated copper prepared by the waste copper regeneration method provided by the embodiment of the present application, and the oxygen content in the low-oxygen copper bar is less than or equal to 30 ppm.

[0078] In some embodiments, the raw material of the low-oxygen copper bar further contains silver and magnesium. In this case, the trace amount of silver is solid-solved in the copper, which can not significantly impair the electrical conductivity and can improve the recrystallization temperature and the anti-creep ability; the magnesium reacts with the free oxygen in the regenerated copper to generate thermodynamically stable in-situ MgO nanoparticles, which can convert the unstable solid-solution oxygen in the regenerated copper into stable and beneficial strengthening phase.

[0079] In some embodiments, the silver content is 5 ppm to 8 ppm.

[0080] In some embodiments, the magnesium content is 30 ppm to 35 ppm.

[0081] The third aspect of the embodiment of the present application provides a preparation method of a low-oxygen copper bar, which comprises the following steps: X10. preparing a copper bar matrix from the regenerated copper.

[0082] The preparation method of the low-oxygen copper bar provided by the embodiment of the present application can obtain the low-oxygen copper bar with very low oxygen content, high tensile strength and high temperature resistance after annealing treatment of the regenerated copper bar prepared into a copper bar matrix.

[0083] In some embodiments, the step X10 of preparing the copper bar matrix from the regenerated copper comprises the following steps: X101. applying a strong static magnetic field and high-temperature holding after the mixed melting of the regenerated copper, silver and magnesium in ultra-high vacuum.

[0084] X102. performing rolling treatment on the copper blank obtained by high-temperature holding to obtain the copper bar matrix.

[0085] In the step of preparing the copper bar matrix from the regenerated copper, the ultra-high vacuum can not only avoid the contact of the regenerated copper with oxygen, but also reduce the melting temperature of the regenerated copper, silver and magnesium, and the magnesium reacts with the oxygen in the regenerated copper to generate MgO during melting; after melting, a strong static magnetic field is applied to the melt to inhibit the diffusion of atoms and the migration of grain boundaries, significantly refine the grain size of the MgO and make the distribution of the MgO extremely uniform, thereby preventing the formation of coarse particles and obtaining the copper bar matrix with fine grains.

[0086] In some embodiments, in the step X101, the vacuum degree of the ultra-high vacuum is less than 10 -3 Pa.

[0087] In some embodiments, the step of mixing and melting the regenerated copper, silver and magnesium in the step X101 comprises the following steps: X1011. adding the silver and the magnesium respectively after the melting of the regenerated copper.

[0088] In some embodiments, in the above step X101, the magnetic field strength of the strong static magnetic field is 10 T or more.

[0089] In some embodiments, in the above step X101, the magnetic field strength of the strong static magnetic field is 10 T to 20 T.

[0090] In some embodiments, in the above step X101, the temperature of the high-temperature holding is 1150°C to 1200°C.

[0091] In some embodiments, in the above step X101, the time of the high-temperature holding is 1 h to 2 h.

[0092] In some embodiments, in the above step X102, the rolling treatment comprises the following steps: X1021. rolling the copper blank into a copper strip with a preset thickness, and annealing the copper strip at a cooling rate of 1.1 x 10 6 °C / s to 1.3 x 10 6 °C / s to 250°C to 350°C, to obtain a low-oxygen copper bar.

[0093] In the above rolling treatment, the cooling rate is 1.1 x 10 6 °C / s to 1.3 x 10 6 °C / s. At such a high cooling rate, the copper strip can form a supersaturated solid solution and a non-equilibrium microstructure. The low-temperature annealing treatment can release internal stress in the copper strip, promote dislocation recombination, form stable "dislocation wall" substructures, and effectively pin the grain boundaries with nano-oxide particles to inhibit grain growth.

[0094] In some embodiments, in the above step X1021, the rolling temperature is 900°C to 1000°C.

[0095] In some embodiments, in the above step X1021, the thickness of the copper strip is 4 mm to 10 mm.

[0096] In some embodiments, in the above step X1021, in the annealing treatment, the copper strip is cooled to below 150°C by water cooling, air cooling or air cooling.

[0097] The following will be further described with reference to specific embodiments. For the convenience of description, the following embodiments and comparative examples involve: (1) The copper content in the scrap copper is 80% ± 5%, and the particle size D50 of the scrap copper is 8 mm.

[0098] (2) The concentration of the sulfuric acid solution is 0.8 mol / L.

[0099] (3) The concentration of the nitric acid is 6 mol / L.

[0100] (4) The preparation of ethyl hydroxyethylidene diphosphonate is as follows: Under argon protection, anhydrous hydroxyethylidene diphosphonic acid (HEDP) is mixed with excess triethyl phosphite, and then refluxed at 130°C. When the amount of distillate reaches more than 90% of the theoretical value, and no new distillate is produced in unit time, the reaction is terminated.

[0101] The excess triethyl phosphite and residual ethanol are removed by vacuum distillation to obtain a crude product.

[0102] The crude product is subjected to high-vacuum distillation to obtain ethyl hydroxyethylidene diphosphonate.

[0103] (5) The butanedione oxime reagent is composed of the following components by mass fraction: Butanedione oxime 0.5%~1%, and the balance is ethanol.

[0104] Example 1 Example 1 provides a method for regenerating waste copper, which comprises the following steps: E10. Impurity removal with sulfuric acid solution Under mechanical stirring, the waste copper is placed in a sulfuric acid solution for constant-temperature impurity removal. The stirring speed is 200 rpm, the constant-temperature impurity removal temperature is 30°C, and the time is 0.8 h.

[0105] E20. Solid product After the reaction system is filtered after impurity removal with a sulfuric acid solution, the filter residue is washed to neutral with water and then dried to a constant weight. The drying temperature is 100°C.

[0106] E30. Preparation of mixed solution Under mechanical stirring and constant-temperature, the solid product is mixed with nitric acid to obtain a mixed solution. The stirring speed is 200 rpm, and the constant-temperature is 20°C.

[0107] E40. Masking copper ions After adjusting the pH value of the mixed solution to 8, the solution is mixed with sodium thiosulfate to obtain a solution after masking copper ions.

[0108] E50. Mixing with impurity complexing agent After maintaining the pH value at 8, the solution after masking copper ions is mixed with ethyl hydroxyethylidene diphosphonate, and then the filtrate is obtained by suction filtration and mixed with butanedione oxime reagent.

[0109] E60. Oxidation complexing E60-1. The solution system obtained in step E50 is subjected to suction filtration, and the filtrate is obtained.

[0110] E60-2. Excess ozone is introduced into the filtrate for oxidation.

[0111] E60-3. Adjust the pH value to 5.0, add excess zinc dimethyl dithiocarbamate and mix and stir. The mixing and stirring speed is 180 rpm and the time is 20 min.

[0112] E60-4. Add polydimethyl diallyl ammonium chloride, stir at 180 rpm for 3 min, then adjust the stirring speed to 35 rpm and stir for 18 min; obtain the complex precipitate solution.

[0113] E70. Reduction treatment E70-1. Filter the complex precipitate solution to obtain the precipitate.

[0114] E70-2. Wash the precipitate with water and dry at 120°C to constant weight.

[0115] E70-3. In a reducing atmosphere of mixed gas with a volume ratio of hydrogen to helium of 1:3, heat to 250°C at a heating rate of 8°C / min for 40 min, then heat to 500°C at a heating rate of 8°C / min for 80 min; obtain the regenerated copper.

[0116] Example 2 Example 2 provides a method for regenerating waste copper, which has basically the same steps as Example 1, except that: E60-3. Adjust the pH value to 4.0, add excess zinc dimethyl dithiocarbamate and mix and stir. The mixing and stirring speed is 150 rpm and the time is 15 min.

[0117] E60-4. Add polydimethyl diallyl ammonium chloride, stir at 200 rpm for 2 min, then adjust the stirring speed to 40 rpm and stir for 10 min; obtain the complex precipitate solution.

[0118] E70-3. In a reducing atmosphere of mixed gas with a volume ratio of hydrogen to helium of 1:2, heat to 200°C at a heating rate of 5°C / min for 60 min, then heat to 400°C at a heating rate of 5°C / min for 120 min; obtain the regenerated copper.

[0119] Example 3 Example 3 provides a method for regenerating waste copper, which has basically the same steps as Example 1, except that: E60-3. Adjust the pH value to 6.0, add excess zinc dimethyl dithiocarbamate and mix and stir. The mixing and stirring speed is 200 rpm and the time is 30 min.

[0120] E60-4. After stirring for 5 min at a stirring speed of 150 rpm, the stirring speed was adjusted to 30 rpm and stirring was performed for 20 min; a complexation precipitation liquid was obtained.

[0121] E70-3. After heating to 300°C at a heating rate of 10°C / min and maintaining the temperature for 30 min in a reducing atmosphere of mixed gas with a volume ratio of hydrogen to helium of 1:5, the temperature was increased to 600°C at a heating rate of 10°C / min and the temperature was maintained for 60 min; regenerated copper was obtained.

[0122] Comparative Example 1 Comparative Example 1 provides a method for regenerating waste copper, and the steps are as follows: D10. Preparation of the mixed liquid The waste copper was mixed with nitric acid under mechanical stirring and at a constant temperature to obtain a mixed liquid. The stirring speed was 200 rpm, and the constant temperature was 20°C.

[0123] D20. Masking of copper ions After adjusting the pH value of the mixed liquid to 8, the solution after masking of copper ions was obtained by mixing with sodium thiosulfate.

[0124] D30. Mixing with impurity complexing agent After mixing the solution after masking of copper ions with ethyl hydroxyethylidene diphosphonate at a pH value of 8, the filtrate was obtained by suction filtration, and the filtrate was mixed with dimethylglyoxime reagent.

[0125] D40. Oxidative complexation D40-1. The solution system obtained in step D30 was subjected to suction filtration, and the filtrate was obtained.

[0126] D40-2. The filtrate was oxidized by passing excess ozone.

[0127] D40-3. The pH value was adjusted to 5.0, and excess zinc dimethyl dithiocarbamate was added and mixed. The mixing speed was 180 rpm, and the mixing time was 20 min.

[0128] D40-4. Polydimethyl diallyl ammonium chloride was added, and after stirring for 3 min at a stirring speed of 180 rpm, the stirring speed was adjusted to 35 rpm and stirring was performed for 18 min; a complexation precipitation liquid was obtained.

[0129] D50. Reduction treatment D50-1. The complexation precipitation liquid was subjected to suction filtration to obtain a precipitate.

[0130] D50-2. The precipitate was washed with water and dried at 120°C to a constant weight.

[0131] D50-3. Under the reducing atmosphere of mixed gas of hydrogen and helium with the volume ratio of 1:3, the temperature was raised to 250℃ at the rate of 8℃ / min and kept for 40 min; then the temperature was raised to 500℃ at the rate of 8℃ / min and kept for 80 min; to obtain the regenerated copper.

[0132] Comparative Example 2 Comparative Example 2 provides a method for regenerating waste copper, the steps are as follows: D11. Impurity removal by sulfuric acid solution Under mechanical stirring, the waste copper was placed in the sulfuric acid solution for constant temperature impurity removal. Among them, the stirring speed of the mechanical stirring was 200 rpm, the temperature of the constant temperature impurity removal was 30℃, and the time was 0.8 h.

[0133] D21. Taking solid After filtering the reaction system after impurity removal by sulfuric acid solution, the filter residue was washed to neutral with water and dried to constant weight. Among them, the drying temperature was 100℃.

[0134] D31. Preparation of mixed solution Under mechanical stirring and constant temperature, the solid was mixed with nitric acid to obtain a mixed solution. Among them, the stirring speed of the mechanical stirring was 200 rpm; the constant temperature was 20℃.

[0135] D41. Complexation D41-1. Adjust the pH value to 5.0, add excess zinc dimethyl dithiocarbamate and mix and stir. Among them, the stirring speed of the mixing and stirring was 180 rpm, and the time was 20 min.

[0136] D41-2. Add polydimethyl diallyl ammonium chloride, stir at the stirring speed of 180 rpm for 3 min, then adjust the stirring speed to 35 rpm and stir for 18 min; to obtain a complexation precipitation liquid.

[0137] D51. Reduction treatment D51-1. The complexation precipitation liquid was filtered to obtain the precipitate.

[0138] D51-2. The precipitate was washed with water and dried to constant weight at 120℃.

[0139] D51-3. Under the reducing atmosphere of mixed gas of hydrogen and helium with the volume ratio of 1:3, the temperature was raised to 250℃ at the rate of 8℃ / min and kept for 40 min; then the temperature was raised to 500℃ at the rate of 8℃ / min and kept for 80 min; to obtain the regenerated copper.

[0140] Comparative Example 3 Comparative Example 3 provides a method for regenerating waste copper, the steps are basically the same as those of Example 1, except that: In step E40, the pH value of the mixed solution is adjusted to 11.

[0141] Comparative Example 4 Comparative Example 4 provides a waste copper regeneration method, the steps of which are basically the same as those of Example 1, except that: In step E60-2, the oxidizing agent is potassium permanganate.

[0142] Example 4 Example 4 provides a low-oxygen copper bar, the raw material of which is composed of the following components in mass fraction: 7 ppm of silver, 32 ppm of magnesium, and the rest being regenerated copper; The regenerated copper is prepared by the waste copper regeneration method of Example 1.

[0143] This example also provides a method for preparing a low-oxygen copper bar, the steps of which are as follows: F10. Melting After the regenerated copper is melted in an ultra-high vacuum, silver and magnesium are added, respectively. After melting, a strong static magnetic field is applied and high-temperature holding is performed. The vacuum degree of the ultra-high vacuum is < 10 -3 Pa; the magnetic field strength of the strong static magnetic field is 15 T; the temperature of the high-temperature holding is 1180℃, and the time is 1.5 h.

[0144] F20. Rolling treatment The copper blank is rolled into a copper strip with a preset thickness, and cooled to 300℃ at a cooling rate of 1.1×10 6 ℃ / s, and then air-cooled to below 150℃ to obtain the low-oxygen copper bar of this example. The rolling temperature is 950℃.

[0145] Example 5 Example 5 provides a low-oxygen copper bar, the raw material of which is composed of the following components in mass fraction: 5 ppm of silver, 30 ppm of magnesium, and the rest being regenerated copper; The regenerated copper is prepared by the waste copper regeneration method of Example 2.

[0146] This example also provides a method for preparing a low-oxygen copper bar, the steps of which are basically the same as those of Example 4, except that the regenerated copper is prepared by the waste copper regeneration method of Example 2.

[0147] Example 6 Example 6 provides a low-oxygen copper bar, the raw material of which is composed of the following components in mass fraction: 8 ppm of silver, 35 ppm of magnesium, and the rest being regenerated copper; The regenerated copper is prepared by the waste copper regeneration method of Example 3.

[0148] The embodiment also provides a preparation method of the low-oxygen copper bar, and the steps are basically the same as those of the embodiment 4, except that the recycled copper is prepared by the waste copper recycling method of the embodiment 3.

[0149] Comparative example 5 The comparative example 5 provides a copper bar, and the raw materials are composed of the following components with mass fractions: 7 ppm of silver, and the rest is recycled copper; The recycled copper is prepared by the waste copper recycling method of the embodiment 1.

[0150] The comparative example also provides a preparation method of the above-mentioned copper bar, and the steps are basically the same as those of the embodiment 4, except that: In the melting of the step F10, only the recycled copper and the silver are melted.

[0151] Comparative example 6 The comparative example 6 provides a preparation method of a copper bar, and the steps are basically the same as those of the embodiment 4, except that: In the melting of the step F10, the magnetic field strength of the strong static magnetic field is 5 T.

[0152] In order to verify the progressiveness of the waste copper recycling method, the low-oxygen copper bar and the preparation method thereof provided by the embodiment, the oxygen content, the recovery rate and the purity of the recycled copper prepared by the embodiment and the comparative examples are detected, and the results are shown in Table 1 below. The tensile strength and the electrical conductivity of the copper bars prepared by the embodiment and the comparative examples are detected, and the results are shown in Table 2 below.

[0153] Table 1

[0154] Table 2

[0155] From the above table, the following conclusions can be drawn: (1) The waste copper recycling method provided by the embodiment removes the metals (such as iron, magnesium and aluminum) that are more active than copper and dissolved in sulfuric acid through the sulfuric acid solution; then dissolves the copper in the mixed nitric acid, masks the copper ions by using a copper masking agent, and further removes the impurity ions by adding an impurity complexing agent; takes the solution, adds an oxidizing agent, releases the copper ions, and then mixes with a copper complexing agent to make the copper precipitate in the form of a complex; takes the precipitate, and reduces it to obtain recycled copper; the oxygen content of the prepared recycled copper is 30 ppm or less; the purity is 99.3% or more, reaching the standard of high-grade copper; and the recovery rate is 98.5% or more, fully realizing the recycling of low-grade waste copper resources.

[0156] (2) The low-oxygen copper plate provided by the embodiment of the present application adds silver and magnesium, and the preparation method of the embodiment of the present application is combined, so that the tensile strength of the low-oxygen copper plate of the embodiment of the present application is above 453MPa, and the electrical conductivity is above 100%IACS.

[0157] It should be noted that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and embodiments having substantially the same configuration and exerting the same effects as the technical idea within the scope of the technical solutions of the present application are all included in the technical scope of the present application. Furthermore, within the scope of the gist of the present application, various modifications that can be thought of by those skilled in the art are applied to the embodiments, and other modes constructed by combining part of the constituent elements of the embodiments are also included in the scope of the present application.

Claims

1. A method for recycling waste copper, characterized in that, Includes the following steps: After impurities are removed from the waste copper with sulfuric acid solution, the solid is mixed with nitric acid to obtain a mixed solution. The mixture is mixed with the copper masking agent and then with the impurity complexing agent; After adding the oxidizing agent to the filtrate, mix it with the copper complexing agent; The precipitate was subjected to reduction treatment to obtain recycled copper.

2. The waste copper recycling method according to claim 1, characterized in that, It satisfies at least one of the following characteristics (1) to (9): (1) The copper content in the scrap copper is below 85%; (2) The particle size D50 of the scrap copper is 1mm~10mm; (3) The solid-liquid ratio of the waste copper to sulfuric acid is 1:2~3; (4) The concentration of the sulfuric acid solution is 0.5 mol / L to 1 mol / L; (5) The concentration of the nitric acid is 4 mol / L to 8 mol / L; (6) The copper masking agent includes sodium thiosulfate; (7) The impurity complexing agent comprises component A and component B; Component A includes ethyl hydroxyethylidene diphosphonate; Component B includes dimethylglyoxime reagent; (8) The oxidant includes ozone; (9) The copper complexing agent includes a precipitant and a flocculant; The precipitant includes zinc dimethyl dithiocarbamate; The flocculant includes polydimethyldiallylammonium chloride.

3. The waste copper recycling method according to claim 1 or 2, characterized in that, It satisfies at least one of the following characteristics (1) to (7): (1) The purification of the sulfuric acid solution includes the following steps: The waste copper was placed in the sulfuric acid solution under mechanical stirring for constant temperature impurity removal; (2) The process of taking solid objects includes the following steps: The reaction system, after being purified with sulfuric acid solution, was filtered, washed, and dried to constant weight. (3) The mixing of the solid with nitric acid includes the following steps: Under mechanical stirring and constant temperature conditions, the solid was mixed with nitric acid to obtain a mixture. (4) The mixing of the mixture with the copper masking agent includes the following steps: After adjusting the pH of the mixture to 7-9, it is mixed with the copper masking agent; (5) The mixing with the impurity complexing agent includes the following steps: Maintain the pH value at 7-9, mix with component A, and then mix the filtrate with component B. (6) The mixing with the copper complexing agent includes the following steps: Adjust the pH value to 4.0~6.0, mix the filtrate after oxidation with the precipitant and stir, then add the flocculant and continue stirring; (7) The reduction process includes the following steps: After removing impurities from the precipitate, it was calcined under a reducing atmosphere.

4. Recycled copper obtained by the waste copper recycling method according to any one of claims 1 to 3.

5. A low-oxygen copper busbar, characterized in that, The raw material comprises the recycled copper as described in claim 4.

6. The low-oxygen copper busbar according to claim 5, characterized in that, The raw materials for the low-oxygen copper busbar also include silver and magnesium.

7. The low-oxygen copper busbar according to claim 6, characterized in that, It satisfies at least one of the following characteristics (1) to (2): (1) The silver content is 5ppm~8ppm; (2) The magnesium content is 30ppm~35ppm.

8. A method for preparing a low-oxygen copper busbar as described in any one of claims 5 to 7, characterized in that, Includes the following steps: The recycled copper is used to make a copper busbar matrix.

9. The method for preparing low-oxygen copper busbars according to claim 8, characterized in that, The process of making copper busbar matrix from recycled copper includes the following steps: In an ultra-high vacuum, recycled copper, silver and magnesium are mixed and melted, then subjected to a strong static magnetic field and kept at high temperature. The copper billet obtained by high-temperature heat preservation is rolled to obtain the copper busbar matrix.

10. The method for preparing low-oxygen copper busbars according to claim 9, characterized in that, It satisfies at least one of the following characteristics (1) to (6): (1) The vacuum degree of the ultra-high vacuum is <10 -3 Pa; (2) The process of mixing and melting recycled copper, silver and magnesium includes the following steps: Silver and magnesium are added separately after the recycled copper is melted; (3) The magnetic field strength of the strong static magnetic field is above 10T; (4) The temperature of the high-temperature insulation is 1150℃~1200℃; (5) The high-temperature heat preservation time is 1h~2h; (6) The rolling process includes the following steps: The copper billet is rolled into a copper strip of a predetermined thickness, and then rolled at 1.1 × 10⁻⁶ mm. 6 ℃ / s ~1.3×10 6 After cooling to 250℃~350℃ at a cooling rate of ℃ / s, annealing is performed to obtain low-oxygen copper busbars.

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