Oxygen-free copper production process

Abstract

The invention discloses an oxygen-free copper production process, which relates to the technical field of metallurgy, and comprises the following steps: S1, raw material pretreatment; step S2, preparing electrolytic copper; s3, pretreatment of electrolytic copper; s4, vacuum melting and microwave assistance are carried out; s5, refining and solidification casting; and step S6, performing post-treatment. The oxygen-free copper produced by the oxygen-free copper production process is high in purity, low and stable in oxygen content and excellent in mechanical property.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgy, and in particular to a production process of oxygen-free copper. Background Art

[0002] In modern electronics, power transmission, and other fields, oxygen-free copper is widely used in information, electronics, electricity, automobiles, refrigeration, and military industries due to its high purity, high conductivity, low oxygen content, good processing properties, and excellent corrosion resistance. With the continuous advancement of industrial technology, the international and domestic requirements for oxygen-free copper are becoming increasingly higher, especially the requirements for oxygen content and purity of oxygen-free copper are constantly increasing.

[0003] Traditional oxygen-free copper production processes suffer from drawbacks such as high investment and energy consumption, low yield and production efficiency, unstable product oxygen content, poor surface quality, high internal porosity, a structure dominated by coarse columnar crystals, poor physical and mechanical properties, and low product quality. Commercially available oxygen-free copper also suffers from various technical flaws, including high impurity content, difficult to control oxygen content, uneven structure, low production efficiency, and unstable quality.

[0004] In order to solve the above technical problems, the Chinese invention patent with authorization announcement number CN110029239B discloses an oxygen-free copper production process, which includes the following steps: cleaning the slag on the furnace walls of the melting furnace and the holding furnace, adding copper material into the melting furnace and melting it into copper liquid; introducing the copper liquid in the melting furnace into the holding furnace, heating the holding furnace and the melting furnace to 1180-1250℃ for burning, and then covering the surface of the copper liquid in the holding furnace and the copper liquid in the melting furnace with a layer of charcoal powder and graphite powder; cooling the melting furnace to 1150℃ and then heating the holding furnace to 1250℃. -1200℃, the holding furnace is cooled to 1140-1175℃; carbon rods are inserted into the copper liquid in the melting furnace and the holding furnace respectively to speed up the deoxidation rate; the melting furnace and the holding furnace are both kept warm, and when the phosphorus content is lower than 10ppm, the production of copper ingots begins; the oxygen content of the ingot is detected, and if the oxygen content is not less than 10ppm, the copper liquid is continued to be covered and kept warm for deoxidation, and if the oxygen content is less than 10ppm, the carbon rod in the melting furnace is pulled out, and an electrolytic plate is added to the melting furnace, the carbon rod in the holding furnace is replaced, and the production of copper ingots continues. The oxygen-free copper produced by this method has a short production cycle and saves production costs. However, the purity and mechanical properties of the oxygen-free copper need to be further improved, and the oxygen content needs to be further reduced.

[0005] It can be seen that it is necessary to seek a simpler and more effective production process to produce oxygen-free copper with high purity, low and stable oxygen content and excellent mechanical properties. Summary of the Invention

[0006] The present invention aims to overcome the deficiencies of the prior art and provide a process for producing oxygen-free copper with high purity, low and stable oxygen content and excellent mechanical properties.

[0007] To achieve the above object, the technical solution adopted by the present invention is: an oxygen-free copper production process, comprising the following steps:

[0008] Step S1, raw material pretreatment: After chemical polishing and hydrophilic treatment, the high-purity copper sheet is subjected to sputtering coating in a magnetron sputtering device using a high-purity copper target in an argon atmosphere to form a uniform copper seed layer; the rough copper is subjected to ultrasonic-plasma combined cleaning;

[0009] Step S2, preparing electrolytic copper: using the crude copper treated in step S1 as an anode and the high-purity copper sheet treated in step S1 as a cathode, electrolysis is performed using a square wave pulse current to obtain electrolytic copper; the electrolyte used uses deionized water as a solvent and includes the following components in the following concentrations: 150-200 g / L copper sulfate pentahydrate, 110-140 g / L sulfuric acid, 6-10 mg / L hydroxyethyl hexahydro-s-triazine, 1-4 mg / L glycerylphosphorylcholine, 0.3-0.8 g / L surfactant, 1-3 mg / L tea polyphenols, 0.1-3 mg / L adenosine, and 0.1-0.8 g / L disodium edetate;

[0010] Step S3, pretreatment of electrolytic copper: crush the electrolytic copper into small pieces, place them in an ultrasonic cleaning machine, add a dilute sulfuric acid solution with a mass fraction of 1-5%, and soak them at an ultrasonic frequency of 40kHz and a power of 300W for 15-22 minutes; then rinse them with deionized water until neutral, and finally dry them in a constant temperature drying oven at 80-90°C for 3-4 hours;

[0011] Step S4, vacuum melting and microwave assistance: The pretreated electrolytic copper is placed in a vacuum induction melting furnace, evacuated and continuously introduced with high-purity helium for deoxidation. When the set vacuum degree is reached, the temperature is increased to 1200-1240°C at a heating rate of 6-10°C / min and the temperature is kept for 10-15 minutes for melting. During the melting process, the surface of the copper liquid is covered with flaky graphite and high-purity helium is introduced for protection. The helium flow rate is controlled at 3-5 L / min, and microwave-assisted treatment is performed for 10-15 minutes.

[0012] Step S5, refining and solidification casting: When the temperature of the copper liquid remains stable, a refining agent is added, electromagnetic stirring is performed for 10-13 minutes, an ultrasonic probe and an electromagnetic coil are simultaneously inserted into the copper liquid to perform ultrasonic-electromagnetic synergistic treatment, slag is skimmed, and the filtrate is filtered using a ceramic filter. The filtrate is poured into a graphite mold preheated to 300-320°C, and a directional solidification technique is used. A cooling device is provided at the bottom of the mold, and the cooling rate is controlled at 45-55°C / s to solidify the copper liquid from the bottom upward to obtain an oxygen-free copper ingot;

[0013] Step S6, post-processing: heat-treating and hot-rolling the oxygen-free copper ingot in sequence to obtain oxygen-free copper.

[0014] Preferably, the power of the sputtering coating in step S1 is 150-200 W, and the deposition time is 10-15 minutes.

[0015] Preferably, the ultrasonic-plasma combined cleaning in step S1 is specifically as follows: the crude copper is first placed in an ultrasonic cleaning tank, and under the action of 40kHz high-frequency ultrasonic waves, an alkaline cleaning agent is used to remove surface oil stains and loose impurities; then it enters a low-temperature plasma treatment chamber, and is bombarded with argon plasma to remove stubborn oxides and residual impurities, so that the surface cleanliness of the crude copper reaches Ra≤0.8μm.

[0016] Preferably, the forward current density of the square wave pulse current in step S2 is 300-350A / m 2 , pulse frequency is 500-1000Hz, duty cycle is 60%-70%; negative current density is 100-160A / m 2 ; In each pulse cycle, the forward current promotes the deposition of copper ions, and the reverse current eliminates the concentration polarization on the electrode surface and improves the crystal quality of cathode copper.

[0017] Preferably, the electrolysis temperature in step S2 is 50-60°C.

[0018] Preferably, the surfactant in step S2 is a mixture of sodium dodecylbenzenesulfonate and polyethylene glycol 400 in a mass ratio of 1:(1-2).

[0019] Preferably, the purity of the high-purity helium in step S4 is not less than 99.999%.

[0020] Preferably, the vacuum degree set in step S4 is (1-2)×10 -5 Pa.

[0021] Preferably, the thickness of the flaky graphite in step S4 is 90-110 mm.

[0022] Preferably, the frequency of the microwave in step S4 is 2.0-2.8 GHz, and the power is 1000-2000 W.

[0023] Preferably, the mass ratio of the copper liquid to the refining agent in step S5 is 100:(0.005-0.01).

[0024] Preferably, the refining agent in step S5 includes the following components in parts by weight: 0.8-1.2 parts of boron, 0.5-0.8 parts of zirconium, 2-4 parts of titanium, 3-5 parts of aluminum, 1-2 parts of yttrium, 3-5 parts of sodium fluorosilicate, and 4-6 parts of calcium fluoride.

[0025] Preferably, the ultrasonic frequency of the ultrasonic-electromagnetic synergistic treatment in step S5 is 40-80 kHz, the power is 200-400 W, the magnetic field strength generated by the electromagnetic coil is 0.5 T, and the treatment time is 15-20 minutes.

[0026] Preferably, the heat treatment temperature in step S6 is 600-620° C., and the holding time is 1-1.5 h.

[0027] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0028] (1) The production process of oxygen-free copper disclosed in the present invention has a short process flow, high speed, low energy consumption, low dependence on equipment, high preparation efficiency and yield rate, is suitable for continuous large-scale production, and has high promotion and application value.

[0029] (2) The oxygen-free copper production process disclosed in the present invention utilizes magnetron sputtering to plate a nano-scale copper seed crystal layer on the cathode during the raw material pretreatment stage, thereby providing a large number of active sites for copper ion deposition and significantly improving the nucleation and growth rates; ultrasonic-plasma combined cleaning is adopted, combining ultrasonic waves and low-temperature plasma to efficiently remove various impurities on the surface of the crude copper, which can effectively improve the cleanliness of the crude copper surface and provide better conditions for the subsequent electrolytic copper purification process; pulse current electrolysis is adopted to optimize copper ion deposition and eliminate concentration polarization by alternating forward and reverse currents.

[0030] (3) The production process of oxygen-free copper disclosed in the present invention uses an electrolyte with deionized water as a solvent, and includes the following components in the following concentrations: 150-200 g / L of copper sulfate pentahydrate, 110-140 g / L of sulfuric acid, 6-10 mg / L of hydroxyethyl hexahydro-s-triazine, 1-4 mg / L of glycerol phosphorylcholine, 0.3-0.8 g / L of surfactant, 1-3 mg / L of tea polyphenols, 0.1-3 mg / L of adenosine, and 0.1-0.8 g / L of disodium ethylenediaminetetraacetic acid; through the mutual coordination and joint action of the components, the prepared electrolyte has good stability, and the electrolytic copper obtained by electrolysis thereof has low impurity content, high purity, low oxygen content and is stable. Glycerylphosphorylcholine molecules have certain polarity and surface activity and can be adsorbed on the cathode surface, which helps regulate the deposition rate and uniformity of copper ions on the cathode surface, allowing copper ions to be deposited more orderly, thereby refining the copper grains, increasing the density and surface smoothness of the cathode copper, and improving the physical properties and appearance quality of the cathode copper. They can also participate in the charge transfer process on the electrode surface, catalyzing or promoting the reduction reaction of copper ions, reducing the activation energy of the reaction, and allowing copper ions to be efficiently reduced and deposited at a lower overpotential, helping to improve electrolysis efficiency and reduce energy consumption. Glycerylphosphorylcholine can interact with certain impurity ions in the electrolyte to form stable complexes or adsorption layers, thereby reducing the activity of impurity ions on the cathode surface, inhibiting co-deposition of impurity ions and copper ions, and facilitating the improvement of the purity of the cathode copper. Glycerylphosphorylcholine has certain antioxidant and complexing abilities and can react with some unstable components or impurities in the electrolyte, reducing their adverse effects on electrolyte performance, improving the stability and service life of the electrolyte, reducing the frequency of replacement due to electrolyte deterioration, and reducing production costs. Tea polyphenols possess strong antioxidant properties, preventing excessive oxidation of metal ions in the electrolyte and the formation of high-valent metal ion impurities. This helps maintain the stability of the metal ion valence in the electrolyte and ensures the proper electrolysis. Tea polyphenol molecules exhibit a certain surface activity and can adsorb on the electrode surface, altering its wettability and improving contact between the electrolyte and the electrode. This promotes uniform deposition of copper ions on the cathode surface, improving the flatness and density of the cathode copper. They can also complex with certain impurity ions in the electrolyte, immobilizing them and reducing their potential for discharge at the cathode, thereby increasing the purity of the cathode copper. Adenosine molecules, with their specific chemical structure and electron cloud distribution, participate in the charge transfer process on the electrode surface. They act as an electron transfer intermediate, lowering the activation energy of the copper ion reduction reaction, thereby accelerating the rate at which copper ions acquire electrons and deposit on the cathode surface and improving electrolysis efficiency. Adenosine adsorbs on the cathode surface, forming an ordered molecular film.This film guides the deposition of copper ions, allowing them to deposit more evenly on the cathode surface, thereby refining the copper grains. Refined grains improve physical properties such as density, hardness, and toughness of the cathode copper. It also improves surface flatness, reduces surface defects, and enhances product quality and appearance. Impurity ions, such as iron and zinc, are often present in the electrolyte. These ions deposit at the cathode along with copper ions, affecting the purity of the cathode copper. Adenosine complexes with these impurity ions to form stable complexes. The presence of these complexes reduces the activity of the impurity ions on the cathode surface, making it difficult for them to deposit during discharge, thereby improving the purity of the cathode copper.

[0031] (4) The production process of oxygen-free copper disclosed in the present invention adopts ultrasonic enhanced cleaning in the pretreatment stage of electrolytic copper, vacuum smelting combined with microwave assistance and high-purity helium protection, adding refining agent and coordinating with electromagnetic stirring, ultrasonic-electromagnetic synergistic treatment, and multiple measures synergistically act to make the copper purity of the final product higher, the impurity content lower, the oxygen content lower, and the mechanical properties of the oxygen-free copper produced higher; the application of ultrasonic-electromagnetic synergistic treatment and directional solidification casting technology enables the copper liquid to achieve directional growth during the solidification process, reduces segregation, and the obtained oxygen-free copper ingot has uniform structure and fine grains, thereby improving the mechanical properties and processing performance of the product.

[0032] (5) The oxygen-free copper production process disclosed in the present invention comprises a refining agent comprising the following components, by weight: 0.8-1.2 parts boron, 0.5-0.8 parts zirconium, 2-4 parts titanium, 3-5 parts aluminum, 1-2 parts yttrium, 3-5 parts sodium fluorosilicate, and 4-6 parts calcium fluoride. The combined effects of the refining agent components further deoxidize and remove impurities, improve microstructure and properties, and contribute to enhanced product quality. DETAILED DESCRIPTION

[0033] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0034] Example 1

[0035] A process for producing oxygen-free copper comprises the following steps:

[0036] Step S1, raw material pretreatment: After chemical polishing and hydrophilic treatment, the high-purity copper sheet is subjected to sputtering coating in a magnetron sputtering device using a high-purity copper target in an argon atmosphere to form a uniform copper seed layer; the rough copper is subjected to ultrasonic-plasma combined cleaning;

[0037] Step S2, preparing electrolytic copper: using the crude copper treated in step S1 as an anode and the high-purity copper sheet treated in step S1 as a cathode, electrolysis is performed using a square wave pulse current to obtain electrolytic copper; the electrolyte used uses deionized water as a solvent and includes the following components in the following concentrations: 150 g / L copper sulfate pentahydrate, 110 g / L sulfuric acid, 6 mg / L hydroxyethyl hexahydro-s-triazine, 1 mg / L glycerylphosphorylcholine, 0.3 g / L surfactant, 1 mg / L tea polyphenols, 0.1 mg / L adenosine, and 0.1 g / L disodium edetate;

[0038] Step S3, pretreatment of electrolytic copper: the electrolytic copper was crushed into small pieces, placed in an ultrasonic cleaning machine, added with a 1% by mass dilute sulfuric acid solution, and soaked for 15 minutes at an ultrasonic frequency of 40kHz and a power of 300W; then rinsed with deionized water until neutral, and finally dried in a constant temperature drying oven at 80°C for 3 hours;

[0039] Step S4, vacuum melting and microwave assistance: The pretreated electrolytic copper is placed in a vacuum induction melting furnace, evacuated and continuously introduced with high-purity helium for deoxidation. When the set vacuum degree is reached, the temperature is increased to 1200°C at a heating rate of 6°C / min and the temperature is kept for 10 minutes for melting. During the melting process, the surface of the copper liquid is covered with flaky graphite and high-purity helium is introduced for protection. The helium flow rate is controlled at 3 L / min, and microwave-assisted treatment is performed for 10 minutes.

[0040] Step S5, refining and solidification casting: After the temperature of the copper liquid remains stable, a refining agent is added, electromagnetic stirring is performed for 10 minutes, an ultrasonic probe and an electromagnetic coil are simultaneously inserted into the copper liquid to perform ultrasonic-electromagnetic synergistic treatment, slag is skimmed, and the liquid is filtered using a ceramic filter. The filtrate is poured into a graphite mold preheated to 300°C, and a directional solidification technique is used. A cooling device is provided at the bottom of the mold, and the cooling rate is controlled at 45°C / s. The copper liquid solidifies from the bottom upward to obtain an oxygen-free copper ingot;

[0041] Step S6, post-processing: heat-treating and hot-rolling the oxygen-free copper ingot in sequence to obtain oxygen-free copper.

[0042] The power of the sputtering coating in step S1 is 150 W, and the deposition time is 10 minutes. The ultrasonic-plasma combined cleaning in step S1 is specifically as follows: the crude copper is first placed in an ultrasonic cleaning tank, and under the action of 40 kHz high-frequency ultrasonic waves, an alkaline cleaning agent is used to remove surface oil and loose impurities; then it enters a low-temperature plasma treatment chamber, and is bombarded with argon plasma to remove stubborn oxides and residual impurities, so that the surface cleanliness of the crude copper reaches Ra ≤ 0.8 μm.

[0043] The forward current density of the square wave pulse current in step S2 is 300A / m 2, the pulse frequency is 500Hz, the duty cycle is 60%; the negative current density is 100A / m 2 ; In each pulse cycle, the forward current promotes the deposition of copper ions, and the reverse current eliminates the concentration polarization on the electrode surface, thereby improving the crystallization quality of the cathode copper; the temperature of the electrolysis in step S2 is 50°C.

[0044] The surfactant in step S2 is a mixture of sodium dodecylbenzenesulfonate and polyethylene glycol 400 in a mass ratio of 1:1; the purity of the high-purity helium in step S4 is not less than 99.999%; the vacuum degree in step S4 is set to 1×10 -5 Pa; the thickness of the flaky graphite in step S4 is 90 mm; the frequency of the microwave in step S4 is 2.0 GHz and the power is 1000 W.

[0045] The mass ratio of the copper liquid and the refining agent in step S5 is 100:0.005; the refining agent in step S5 includes the following components in parts by weight: 0.8 parts of boron, 0.5 parts of zirconium, 2 parts of titanium, 3 parts of aluminum, 1 part of yttrium, 3 parts of sodium fluorosilicate, and 4 parts of calcium fluoride; the ultrasonic frequency of the ultrasonic-electromagnetic synergistic treatment in step S5 is 40 kHz, the power is 200 W, the magnetic field strength generated by the electromagnetic coil is 0.5 T, and the treatment time is 15 minutes; the heat treatment temperature in step S6 is 600° C., and the holding time is 1 hour.

[0046] Example 2

[0047] A process for producing oxygen-free copper comprises the following steps:

[0048] Step S1, raw material pretreatment: After chemical polishing and hydrophilic treatment, the high-purity copper sheet is subjected to sputtering coating in a magnetron sputtering device using a high-purity copper target in an argon atmosphere to form a uniform copper seed layer; the rough copper is subjected to ultrasonic-plasma combined cleaning;

[0049] Step S2, preparing electrolytic copper: using the crude copper treated in step S1 as an anode and the high-purity copper sheet treated in step S1 as a cathode, electrolysis is performed using a square wave pulse current to obtain electrolytic copper; the electrolyte used uses deionized water as a solvent and includes the following components in the following concentrations: 160 g / L copper sulfate pentahydrate, 120 g / L sulfuric acid, 7 mg / L hydroxyethyl hexahydro-s-triazine, 2 mg / L glycerylphosphorylcholine, 0.4 g / L surfactant, 1.5 mg / L tea polyphenols, 1 mg / L adenosine, and 0.2 g / L disodium edetate;

[0050] Step S3, pretreatment of electrolytic copper: the electrolytic copper was crushed into small pieces, placed in an ultrasonic cleaning machine, added with a 2% by mass dilute sulfuric acid solution, and soaked at 40kHz ultrasonic frequency and 300W power for 17 minutes; then rinsed with deionized water until neutral, and finally dried in a constant temperature drying oven at 83°C for 3.2 hours;

[0051] Step S4, vacuum melting and microwave assistance: The pretreated electrolytic copper is placed in a vacuum induction melting furnace, evacuated and continuously introduced with high-purity helium for deoxidation. When the set vacuum degree is reached, the temperature is increased to 1210°C at a heating rate of 7°C / min and the temperature is kept for 12 minutes for melting. During the melting process, the surface of the copper liquid is covered with flaky graphite and high-purity helium is introduced for protection. The helium flow rate is controlled at 3.5 L / min, and microwave-assisted treatment is performed for 12 minutes.

[0052] Step S5, refining and solidification casting: After the temperature of the copper liquid remains stable, a refining agent is added, electromagnetic stirring is performed for 11 minutes, an ultrasonic probe and an electromagnetic coil are simultaneously inserted into the copper liquid to perform ultrasonic-electromagnetic synergistic treatment, slag is skimmed, and the filtrate is filtered using a ceramic filter. The filtrate is poured into a graphite mold preheated to 305°C, and a directional solidification technique is used. A cooling device is provided at the bottom of the mold, and the cooling rate is controlled at 48°C / s. The copper liquid solidifies from the bottom upward to obtain an oxygen-free copper ingot;

[0053] Step S6, post-processing: heat-treating and hot-rolling the oxygen-free copper ingot in sequence to obtain oxygen-free copper.

[0054] The power of the sputtering coating in step S1 is 160 W, and the deposition time is 12 minutes. The ultrasonic-plasma combined cleaning in step S1 is specifically as follows: the crude copper is first placed in an ultrasonic cleaning tank, and under the action of 40 kHz high-frequency ultrasonic waves, an alkaline cleaning agent is used to remove surface oil and loose impurities; then it enters a low-temperature plasma treatment chamber, and is bombarded with argon plasma to remove stubborn oxides and residual impurities, so that the surface cleanliness of the crude copper reaches Ra ≤ 0.8 μm.

[0055] The forward current density of the square wave pulse current in step S2 is 320A / m 2 , the pulse frequency is 700Hz, the duty cycle is 63%; the negative current density is 120A / m 2 ; In each pulse cycle, the forward current promotes the deposition of copper ions, and the reverse current eliminates the concentration polarization on the electrode surface, thereby improving the crystallization quality of the cathode copper; the electrolysis temperature in step S2 is 53°C; the surfactant in step S2 is a mixture of sodium dodecylbenzenesulfonate and polyethylene glycol 400 in a mass ratio of 1:1.3.

[0056] The purity of the high-purity helium in step S4 is not less than 99.999%; the vacuum degree in step S4 is set to 1.3×10-5 Pa; the thickness of the flaky graphite in step S4 is 95 mm; the frequency of the microwave in step S4 is 2.2 GHz, and the power is 1300 W; the mass ratio of the copper liquid to the refining agent in step S5 is 100:0.007; the refining agent in step S5 comprises the following components in parts by weight: 0.9 parts of boron, 0.6 parts of zirconium, 2.5 parts of titanium, 3.5 parts of aluminum, 1.2 parts of yttrium, 3.5 parts of sodium fluorosilicate, and 4.5 parts of calcium fluoride; the ultrasonic frequency of the ultrasonic-electromagnetic synergistic treatment in step S5 is 50 kHz, the power is 250 W, the magnetic field strength generated by the electromagnetic coil is 0.5 T, and the treatment time is 17 minutes; the temperature of the heat treatment in step S6 is 605° C., and the holding time is 1 hour.

[0057] Example 3

[0058] A process for producing oxygen-free copper comprises the following steps:

[0059] Step S1, raw material pretreatment: After chemical polishing and hydrophilic treatment, the high-purity copper sheet is subjected to sputtering coating in a magnetron sputtering device using a high-purity copper target in an argon atmosphere to form a uniform copper seed layer; the rough copper is subjected to ultrasonic-plasma combined cleaning;

[0060] Step S2, preparation of electrolytic copper: using the crude copper treated in step S1 as an anode and the high-purity copper sheet treated in step S1 as a cathode, electrolysis is performed using a square wave pulse current to obtain electrolytic copper; the electrolyte used uses deionized water as a solvent and includes the following components in the following concentrations: 180 g / L copper sulfate pentahydrate, 125 g / L sulfuric acid, 8 mg / L hydroxyethyl hexahydro-s-triazine, 2.5 mg / L glycerylphosphorylcholine, 0.6 g / L surfactant, 2 mg / L tea polyphenols, 1.5 mg / L adenosine, and 0.5 g / L disodium edetate;

[0061] Step S3, pretreatment of electrolytic copper: the electrolytic copper was crushed into small pieces, placed in an ultrasonic cleaning machine, added with a 3.5% by mass dilute sulfuric acid solution, and soaked for 19 minutes at an ultrasonic frequency of 40kHz and a power of 300W; then rinsed with deionized water until neutral, and finally dried in a constant temperature drying oven at 85°C for 3.5 hours;

[0062] Step S4, vacuum melting and microwave assistance: The pretreated electrolytic copper is placed in a vacuum induction melting furnace, evacuated and continuously introduced with high-purity helium for deoxidation. When the set vacuum degree is reached, the temperature is increased to 1220°C at a heating rate of 8°C / min and the temperature is kept for 13 minutes for melting. During the melting process, the surface of the copper liquid is covered with flaky graphite and high-purity helium is introduced for protection. The helium flow rate is controlled at 4 L / min, and microwave-assisted treatment is performed for 13 minutes.

[0063] Step S5, refining and solidification casting: After the temperature of the copper liquid remains stable, a refining agent is added, electromagnetic stirring is performed for 12 minutes, an ultrasonic probe and an electromagnetic coil are simultaneously inserted into the copper liquid to perform ultrasonic-electromagnetic synergistic treatment, slag is skimmed, and the filtrate is filtered using a ceramic filter. The filtrate is poured into a graphite mold preheated to 310°C, and a directional solidification technique is used. A cooling device is provided at the bottom of the mold, and the cooling rate is controlled at 50°C / s. The copper liquid is solidified from the bottom upward to obtain an oxygen-free copper ingot;

[0064] Step S6, post-processing: heat-treating and hot-rolling the oxygen-free copper ingot in sequence to obtain oxygen-free copper.

[0065] The power of the sputtering coating in step S1 is 180W, and the deposition time is 13 minutes. The ultrasonic-plasma combined cleaning in step S1 is specifically as follows: the crude copper is first placed in an ultrasonic cleaning tank, and under the action of 40kHz high-frequency ultrasonic waves, an alkaline cleaning agent is used to remove surface oil and loose impurities; then it enters a low-temperature plasma treatment chamber, and is bombarded with argon plasma to remove stubborn oxides and residual impurities, so that the surface cleanliness of the crude copper reaches Ra≤0.8μm; the forward current density of the square wave pulse current in step S2 is 330A / m 2 , the pulse frequency is 800Hz, the duty cycle is 65%; the negative current density is 130A / m 2 ; In each pulse cycle, the forward current promotes the deposition of copper ions, and the reverse current eliminates the concentration polarization on the electrode surface, thereby improving the crystallization quality of the cathode copper; the electrolysis temperature in step S2 is 55°C; the surfactant in step S2 is a mixture of sodium dodecylbenzenesulfonate and polyethylene glycol 400 in a mass ratio of 1:1.5.

[0066] The purity of the high-purity helium in step S4 is not less than 99.999%; the vacuum degree in step S4 is set to 1.5×10 -5 Pa; the thickness of the flaky graphite in step S4 is 100 mm; the frequency of the microwave in step S4 is 2.5 GHz, and the power is 1500 W; the mass ratio of the copper liquid to the refining agent in step S5 is 100:0.008; the refining agent in step S5 comprises the following components in parts by weight: 1 part boron, 0.65 part zirconium, 3 parts titanium, 4 parts aluminum, 1.5 parts yttrium, 4 parts sodium fluorosilicate, and 5 parts calcium fluoride; the ultrasonic frequency of the ultrasonic-electromagnetic synergistic treatment in step S5 is 60 kHz, the power is 300 W, the magnetic field strength generated by the electromagnetic coil is 0.5 T, and the treatment time is 18 minutes; the temperature of the heat treatment in step S6 is 610° C., and the holding time is 1 hour.

[0067] Example 4

[0068] A process for producing oxygen-free copper comprises the following steps:

[0069] Step S1, raw material pretreatment: After chemical polishing and hydrophilic treatment, the high-purity copper sheet is subjected to sputtering coating in a magnetron sputtering device using a high-purity copper target in an argon atmosphere to form a uniform copper seed layer; the rough copper is subjected to ultrasonic-plasma combined cleaning;

[0070] Step S2, preparation of electrolytic copper: using the crude copper treated in step S1 as an anode and the high-purity copper sheet treated in step S1 as a cathode, electrolysis is performed using a square wave pulse current to obtain electrolytic copper; the electrolyte used uses deionized water as a solvent and includes the following components in the following concentrations: 190 g / L copper sulfate pentahydrate, 135 g / L sulfuric acid, 9.5 mg / L hydroxyethyl hexahydro-s-triazine, 3.5 mg / L glycerylphosphorylcholine, 0.7 g / L surfactant, 2.5 mg / L tea polyphenols, 2.5 mg / L adenosine, and 0.7 g / L disodium edetate;

[0071] Step S3, pretreatment of electrolytic copper: the electrolytic copper was crushed into small pieces, placed in an ultrasonic cleaning machine, added with a 4% by mass dilute sulfuric acid solution, and soaked at 40kHz ultrasonic frequency and 300W power for 21 minutes; then rinsed with deionized water until neutral, and finally dried in a constant temperature drying oven at 88°C for 3.8 hours;

[0072] Step S4, vacuum melting and microwave-assisted melting: The pretreated electrolytic copper is placed in a vacuum induction melting furnace, evacuated, and high-purity helium is continuously introduced for deoxidation. When the set vacuum degree is reached, the temperature is increased to 1235°C at a heating rate of 9.5°C / min and kept at this temperature for 14 minutes for melting. During the melting process, the surface of the copper liquid is covered with flaky graphite and high-purity helium is introduced for protection. The helium flow rate is controlled at 4.5 L / min, and microwave-assisted treatment is performed for 14 minutes.

[0073] Step S5, refining and solidification casting: After the temperature of the copper liquid remains stable, a refining agent is added, electromagnetic stirring is performed for 12.5 minutes, an ultrasonic probe and an electromagnetic coil are simultaneously inserted into the copper liquid to perform ultrasonic-electromagnetic synergistic treatment, slag is skimmed, and the filtrate is filtered using a ceramic filter. The filtrate is poured into a graphite mold preheated to 315°C, and a directional solidification technique is used. A cooling device is provided at the bottom of the mold, and the cooling rate is controlled at 53°C / s to solidify the copper liquid from the bottom upward to obtain an oxygen-free copper ingot;

[0074] Step S6, post-processing: heat-treating and hot-rolling the oxygen-free copper ingot in sequence to obtain oxygen-free copper.

[0075] The power of the sputtering coating in step S1 is 190W, and the deposition time is 14 minutes. The ultrasonic-plasma combined cleaning in step S1 is specifically as follows: the crude copper is first placed in an ultrasonic cleaning tank, and under the action of 40kHz high-frequency ultrasonic waves, an alkaline cleaning agent is used to remove surface oil and loose impurities; then it enters a low-temperature plasma treatment chamber, and is bombarded with argon plasma to remove stubborn oxides and residual impurities, so that the surface cleanliness of the crude copper reaches Ra≤0.8μm; the forward current density of the square wave pulse current in step S2 is 340A / m 2 , the pulse frequency is 900Hz, the duty cycle is 68%; the negative current density is 150A / m 2 ; In each pulse cycle, the forward current promotes the deposition of copper ions, and the reverse current eliminates the concentration polarization on the electrode surface, thereby improving the crystallization quality of the cathode copper; the electrolysis temperature in step S2 is 58°C; the surfactant in step S2 is a mixture of sodium dodecylbenzenesulfonate and polyethylene glycol 400 in a mass ratio of 1:1.8.

[0076] The purity of the high-purity helium in step S4 is not less than 99.999%; the vacuum degree in step S4 is set to 1.8×10 -5 Pa; the thickness of the flaky graphite in step S4 is 105 mm; the frequency of the microwave in step S4 is 2.7 GHz, and the power is 1900 W; the mass ratio of the copper liquid to the refining agent in step S5 is 100:0.009; the refining agent in step S5 comprises the following components in parts by weight: 1.1 parts of boron, 0.75 parts of zirconium, 3.5 parts of titanium, 4.5 parts of aluminum, 1.8 parts of yttrium, 4.5 parts of sodium fluorosilicate, and 5.5 parts of calcium fluoride; the ultrasonic frequency of the ultrasonic-electromagnetic synergistic treatment in step S5 is 75 kHz, the power is 350 W, the magnetic field strength generated by the electromagnetic coil is 0.5 T, and the treatment time is 19 minutes; the temperature of the heat treatment in step S6 is 615° C., and the holding time is 1 hour.

[0077] Example 5

[0078] A process for producing oxygen-free copper comprises the following steps:

[0079] Step S1, raw material pretreatment: After chemical polishing and hydrophilic treatment, the high-purity copper sheet is subjected to sputtering coating in a magnetron sputtering device using a high-purity copper target in an argon atmosphere to form a uniform copper seed layer; the rough copper is subjected to ultrasonic-plasma combined cleaning;

[0080] Step S2, preparation of electrolytic copper: using the crude copper treated in step S1 as an anode and the high-purity copper sheet treated in step S1 as a cathode, electrolysis is performed using a square wave pulse current to obtain electrolytic copper; the electrolyte used uses deionized water as a solvent and includes the following components in the following concentrations: 200 g / L copper sulfate pentahydrate, 140 g / L sulfuric acid, 10 mg / L hydroxyethyl hexahydro-s-triazine, 4 mg / L glycerylphosphorylcholine, 0.8 g / L surfactant, 3 mg / L tea polyphenols, 3 mg / L adenosine, and 0.8 g / L disodium edetate;

[0081] Step S3, pretreatment of electrolytic copper: the electrolytic copper was crushed into small pieces, placed in an ultrasonic cleaning machine, added with a 5% by mass dilute sulfuric acid solution, and soaked at 40kHz ultrasonic frequency and 300W power for 22 minutes; then rinsed with deionized water until neutral, and finally dried in a constant temperature drying oven at 90°C for 4 hours;

[0082] Step S4, vacuum melting and microwave assistance: The pretreated electrolytic copper is placed in a vacuum induction melting furnace, evacuated and continuously introduced with high-purity helium for deoxidation. When the set vacuum degree is reached, the temperature is increased to 1240°C at a heating rate of 10°C / min and the temperature is kept for 15 minutes for melting. During the melting process, the surface of the copper liquid is covered with flaky graphite and high-purity helium is introduced for protection. The helium flow rate is controlled at 5 L / min, and microwave-assisted treatment is performed for 15 minutes.

[0083] Step S5, refining and solidification casting: After the temperature of the copper liquid remains stable, a refining agent is added, electromagnetic stirring is performed for 13 minutes, an ultrasonic probe and an electromagnetic coil are simultaneously inserted into the copper liquid to perform ultrasonic-electromagnetic synergistic treatment, slag is skimmed, and the filtrate is filtered using a ceramic filter. The filtrate is poured into a graphite mold preheated to 320°C, and a directional solidification technique is used. A cooling device is provided at the bottom of the mold, and the cooling rate is controlled at 55°C / s to solidify the copper liquid from the bottom upward to obtain an oxygen-free copper ingot;

[0084] Step S6, post-processing: heat-treating and hot-rolling the oxygen-free copper ingot in sequence to obtain oxygen-free copper.

[0085] The power of the sputtering coating in step S1 is 200W, and the deposition time is 15 minutes. The ultrasonic-plasma combined cleaning in step S1 is specifically as follows: the crude copper is first placed in an ultrasonic cleaning tank, and under the action of 40kHz high-frequency ultrasonic waves, an alkaline cleaning agent is used to remove surface oil and loose impurities; then it enters a low-temperature plasma treatment chamber, and is bombarded with argon plasma to remove stubborn oxides and residual impurities, so that the surface cleanliness of the crude copper reaches Ra≤0.8μm; the forward current density of the square wave pulse current in step S2 is 350A / m 2 , the pulse frequency is 1000Hz, the duty cycle is 70%; the negative current density is 160A / m2 ; In each pulse cycle, the forward current promotes the deposition of copper ions, and the reverse current eliminates the concentration polarization on the electrode surface, thereby improving the crystallization quality of the cathode copper; the electrolysis temperature in step S2 is 60°C; the surfactant in step S2 is a mixture of sodium dodecylbenzenesulfonate and polyethylene glycol 400 in a mass ratio of 1:2.

[0086] The purity of the high-purity helium in step S4 is not less than 99.999%; the vacuum degree in step S4 is set to 2×10 -5 Pa; the thickness of the flaky graphite in step S4 is 110 mm; the frequency of the microwave in step S4 is 2.8 GHz, and the power is 2000 W; the mass ratio of the copper liquid to the refining agent in step S5 is 100:0.01; the refining agent in step S5 comprises the following components in parts by weight: 1.2 parts of boron, 0.8 parts of zirconium, 4 parts of titanium, 5 parts of aluminum, 2 parts of yttrium, 5 parts of sodium fluorosilicate, and 6 parts of calcium fluoride; the ultrasonic frequency of the ultrasonic-electromagnetic synergistic treatment in step S5 is 80 kHz, the power is 400 W, the magnetic field strength generated by the electromagnetic coil is 0.5 T, and the treatment time is 20 minutes; the temperature of the heat treatment in step S6 is 620° C., and the holding time is 1 hour.

[0087] Comparative Example 1

[0088] This example provides an oxygen-free copper production process, which is basically the same as Example 1, except that glycerolphosphorylcholine and zirconium are not added.

[0089] Comparative Example 2

[0090] This example provides an oxygen-free copper production process, which is basically the same as Example 1, except that adenosine and titanium are not added.

[0091] Comparative Example 3

[0092] This example provides an oxygen-free copper production process, which is basically the same as Example 1, except that there is no sputtering coating and microwave-assisted step, and the current density is 250A / m 2 The current replaces the square wave pulse current.

[0093] In order to further illustrate the beneficial technical effects of the oxygen-free copper production process involved in each embodiment of the present invention, the oxygen-free copper produced by the oxygen-free copper production process involved in Examples 1-5 and Comparative Examples 1-3 was subjected to composition analysis, and its tensile properties were tested in accordance with GB / T228.1-2021 "Tensile Test of Metal Materials Part 1: Room Temperature Test Method". The results are shown in Table 1.

[0094] Table 1

[0095]

[0096] As can be seen from the above table, the oxygen-free copper produced by the oxygen-free copper production process involved in each embodiment of the present invention has higher purity, tensile strength and lower oxygen content than the comparative example product. The combined use of glycerol phosphorylcholine, zirconium, adenosine, titanium, sputtering coating, microwave assistance, and square wave pulse current is beneficial to improving purity and mechanical properties and reducing oxygen content.

[0097] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A process for producing oxygen-free copper, characterized in that: The steps include: Step S1, raw material pretreatment: After chemical polishing and hydrophilic treatment, the high-purity copper sheet is subjected to sputtering coating in a magnetron sputtering device using a high-purity copper target in an argon atmosphere to form a uniform copper seed layer; the rough copper is subjected to ultrasonic-plasma combined cleaning; Step S2, preparation of electrolytic copper: using the crude copper treated in step S1 as an anode and the high-purity copper sheet treated in step S1 as a cathode, electrolysis is performed using a square wave pulse current to obtain electrolytic copper; Step S3, pretreatment of electrolytic copper: crushing the electrolytic copper into small pieces and then pretreatment; Step S4, vacuum melting and microwave assistance: The pretreated electrolytic copper is placed in a vacuum induction melting furnace, evacuated and continuously introduced with high-purity helium for deoxidation. When the set vacuum degree is reached, the temperature is increased to 1200-1240°C at a heating rate of 6-10°C / min and the temperature is kept for 10-15 minutes for melting. During the melting process, the surface of the copper liquid is covered with flaky graphite and high-purity helium is introduced for protection. The helium flow rate is controlled at 3-5 L / min, and microwave-assisted treatment is performed for 10-15 minutes. Step S5, refining and solidification casting: When the temperature of the copper liquid remains stable, a refining agent is added, electromagnetic stirring is performed for 10-13 minutes, an ultrasonic probe and an electromagnetic coil are simultaneously inserted into the copper liquid to perform ultrasonic-electromagnetic synergistic treatment, slag is skimmed, and the filtrate is filtered using a ceramic filter. The filtrate is poured into a graphite mold preheated to 300-320°C, and a directional solidification technique is used. A cooling device is provided at the bottom of the mold, and the cooling rate is controlled at 45-55°C / s to solidify the copper liquid from the bottom upward to obtain an oxygen-free copper ingot; Step S6, post-processing: heat-treating and hot-rolling the oxygen-free copper ingot in sequence to obtain oxygen-free copper.

2. The oxygen-free copper production process according to claim 1, characterized in that: The power of the sputtering coating in step S1 is 150-200W, and the deposition time is 10-15 minutes. The ultrasonic-plasma combined cleaning in step S1 is specifically as follows: the crude copper is first placed in an ultrasonic cleaning tank, and under the action of 40kHz high-frequency ultrasonic waves, an alkaline cleaning agent is used to remove surface oil and loose impurities; then it enters a low-temperature plasma treatment chamber, and is bombarded with argon plasma to remove stubborn oxides and residual impurities, so that the surface cleanliness of the crude copper reaches Ra≤0.8μm.

3. The oxygen-free copper production process according to claim 1, characterized in that: The electrolyte used in the electrolysis in step S2 uses deionized water as a solvent and includes the following components in the following concentrations: 150-200 g / L of copper sulfate pentahydrate, 110-140 g / L of sulfuric acid, 6-10 mg / L of hydroxyethyl hexahydro-s-triazine, 1-4 mg / L of glycerol phosphorylcholine, 0.3-0.8 g / L of surfactant, 1-3 mg / L of tea polyphenols, 0.1-3 mg / L of adenosine, and 0.1-0.8 g / L of disodium edetate; the surfactant is a mixture of sodium dodecylbenzenesulfonate and polyethylene glycol 400 in a mass ratio of 1:(1-2).

4. The oxygen-free copper production process according to claim 1, characterized in that: The forward current density of the square wave pulse current in step S2 is 300-350A / m 2 , pulse frequency is 500-1000Hz, duty cycle is 60%-70%; negative current density is 100-160A / m 2 ; In each pulse cycle, the forward current promotes the deposition of copper ions, and the reverse current eliminates the concentration polarization on the electrode surface, thereby improving the crystallization quality of the cathode copper; the temperature of the electrolysis in step S2 is 50-60°C.

5. The oxygen-free copper production process according to claim 1, characterized in that: The pretreatment in step S3 is specifically as follows: placing the electrolytic copper pieces in an ultrasonic cleaning machine, adding a dilute sulfuric acid solution with a mass fraction of 1-5%, and soaking them at an ultrasonic frequency of 40kHz and a power of 300W for 15-22 minutes; then rinsing them with deionized water until neutral, and finally drying them in a constant temperature drying oven at 80-90°C for 3-4 hours.

6. The oxygen-free copper production process according to claim 1, characterized in that: The purity of the high-purity helium gas in step S4 is not less than 99.999%; the vacuum degree set in step S4 is (1-2)×10-5Pa.

7. The oxygen-free copper production process according to claim 1, characterized in that: The thickness of the flaky graphite in step S4 is 90-110 mm; the frequency of the microwave in step S4 is 2.0-2.8 GHz, and the power is 1000-2000 W.

8. The oxygen-free copper production process according to claim 1, characterized in that: The mass ratio of the copper liquid and the refining agent in step S5 is 100:(0.005-0.01); the refining agent in step S5 includes the following components in parts by weight: 0.8-1.2 parts of boron, 0.5-0.8 parts of zirconium, 2-4 parts of titanium, 3-5 parts of aluminum, 1-2 parts of yttrium, 3-5 parts of sodium fluorosilicate, and 4-6 parts of calcium fluoride.

9. The oxygen-free copper production process according to claim 1, characterized in that: The ultrasonic-electromagnetic synergistic treatment in step S5 has an ultrasonic frequency of 40-80 kHz, a power of 200-400 W, a magnetic field strength of 0.5 T generated by the electromagnetic coil, and a treatment time of 15-20 minutes.

10. The oxygen-free copper production process according to claim 1, characterized in that: The heat treatment temperature in step S6 is 600-620° C., and the holding time is 1-1.5 hours.

Images