Preparation method and device of low-oxygen low-sulfur high-purity copper

Abstract

The invention belongs to the field of copper smelting, and particularly relates to a preparation method of low-oxygen low-sulfur high-purity copper, various additives are matched, a protective film is formed outside a cathode in the electrolysis process, other impurities are isolated, and the preparation method is suitable for standard industrial production of the low-oxygen low-sulfur high-purity copper and has the advantages of being low in cost, easy to operate, high in purity and capable of achieving continuous production.

Description

Technical Field

[0001] The invention relates to the field of copper smelting, and in particular to a method and device for preparing low-oxygen, low-sulfur and high-purity copper. Background Art

[0002] Copper has good electrical conductivity, thermal conductivity, weldability, plasticity, ductility and excellent cold working performance, and is non-magnetic. Oxygen-free copper refers to pure copper with very low oxygen content and impurity content. Oxygen-free copper material overcomes the shortcomings of copper containing impurities, such as low yield strength after annealing and poor creep resistance at high temperatures. It has excellent electrical and thermal conductivity, no hydrogen embrittlement, good ductility, corrosion resistance, etc., and is widely used in the field of electronic information transmission.

[0003] With the rapid development of communications, microelectronic chips, integrated circuits, rail transit, new energy vehicles, aerospace, national defense and other fields represented by 5G technology in my country, as well as the implementation of the new infrastructure strategic plan proposed by the central government, higher requirements have been put forward for high-performance copper and copper alloy plates and strips. Many fields require the expansion of ultra-thin copper plates and strips with low thermal resistance, high uniform heat flux, rapid heat diffusion, and light weight. According to incomplete statistics, the demand for copper plates and strips required in these fields is about 20,000 to 30,000 tons / year, and currently high-end ultra-low oxygen copper plates and strips need to be imported from developed countries such as Japan and Germany. The present invention will use electrolytic refining technology to prepare low-sulfur and low-oxygen cathode copper, which can be widely used in communications, electricity, microelectronics, lead frames, 5G, new infrastructure, artificial intelligence and many other fields.

[0004] In the prior art, oxygen-free copper is divided into ordinary oxygen-free copper and high-purity oxygen-free copper. Ordinary oxygen-free copper is smelted in an induction furnace, and the smelting of high-purity oxygen-free copper usually adopts a vacuum smelting process. The entire process is carried out under a vacuum state, which can reduce the interference of external factors in the processing process, and thus is conducive to obtaining high-purity oxygen-free copper with a low total impurity content. These two methods have complex equipment, expensive cost, and very high operating and maintenance costs. Electrolytic refining is the most basic and most commonly used method for preparing high-purity copper. Usually, the anode copper plate is suspended in the electrolyte and made into high-purity copper after electrolysis.

[0005] For example, the invention patent entitled "A Method for Preparing Oxygen-Free Copper" (application number 202211102875.3, hereinafter referred to as Document 1) discloses: the copper raw material is vacuum melted and impurities removed to obtain the expected copper liquid, and then transferred to a refining furnace in a non-vacuum state through a sealed flow channel, the refining furnace comprising an insulating refining chamber formed with a first cavity, and a to-be-casting buffer chamber formed with a second cavity sealed and connected to the first cavity, so that the expected copper liquid is refined and impurities removed in the insulating refining chamber to obtain the refined copper liquid contained in the first cavity, and the refined copper liquid is made to flow out of the first cavity and flow upward under the action of a first external force, and then flow into the second cavity; when the first external force is weakened or removed, the refined copper liquid stops flowing into the second cavity; the refined copper liquid entering the second cavity is made to flow downward and enter the cold zone in the crystallizer in the up and down directions for crystallization, and the oxygen-free copper is pulled out in the up and down directions. This solution can achieve the preparation of high-purity, large-size oxygen-free copper, and can also achieve continuous or intermittent casting, low energy consumption and high efficiency. However, this solution is smelted under vacuum conditions, and the equipment and energy consumption are too high.

[0006] For example, the invention patent entitled "A Method for Preparing High-Purity Oxygen-Free Copper" (application number 202311583988.4, hereinafter referred to as Document 2) discloses: adding cathode copper raw materials to a smelting furnace protected by a reducing atmosphere for smelting, adding different covering agents, and blowing inert gas from the bottom for deoxidation and impurity removal. Finally, the molten copper is poured into the crystallizer and cast through a vertical continuous casting device. The obtained high-purity oxygen-free copper has a purity of more than 99.99% and an oxygen content of 3 to 5 ppm. This scheme does not require the use of a vacuum induction furnace, the process is simple, the production efficiency is improved, and the production cost is reduced. However, although this scheme abolishes the operating conditions for smelting under a vacuum environment, the thickness of both covering agents needs to be 15 to 20 cm, which has high requirements and high consumption, and is only suitable for the preparation of small samples in the laboratory, and cannot be achieved on a large scale.

[0007] Therefore, how to prepare high-purity oxygen-free copper and apply and produce it is a difficult problem that technicians in this field have been working on. Summary of the invention

[0008] The object of the present invention is to provide a method for preparing low-oxygen, low-sulfur and high-purity copper, which has low requirements on equipment and environment and is suitable for application in standardized industrial production.

[0009] To achieve the above object, the technical scheme adopted by the present invention is: a method for preparing low-oxygen, low-sulfur and high-purity copper, using a copper plate with a copper content greater than 99.90% as an anode, a stainless steel plate or a titanium plate as a cathode, and a copper sulfate solution as an electrolyte, at 25 to 45°C and a current density of 100 to 300A / m 2 , electrolysis is carried out under the protection of nitrogen atmosphere; in the copper sulfate solution: Cu 2+ Concentration 30-50g / L, sulfuric acid concentration 100-180g / L;

[0010] During the electrolysis process, hydrochloric acid, additive A, additive B, and additive C are added and continuously replenished to maintain the concentration of hydrochloric acid in the electrolyte at 10-50 mg / L, the concentration of additive A at 3-20 mg / L, the concentration of additive B at 5-10 mg / L, and the concentration of additive C at 5-10 mg / L; after the electrolysis is completed, high-purity cathode copper is obtained;

[0011] Specifically, the additive A is a composite active protein extracted from animals, with a molecular weight of 10-25 kDa and a freezing strength of 100-120; the animal composite protein in this molecular weight range has low viscosity, and forms a thin film on the surface of the cathode plate after dissolution, which can reduce the adhesion of particulate matter and suspended matter in the electrolysis system, and has good crystallinity, which can ensure the quality of cathode copper; in addition, the composite active protein has good buffering properties, which can buffer the concentration of metal ions in the electrolysis system, reduce the diffusion rate of copper ions, and improve the uniformity of copper ion deposition. If the freezing strength of the additive is too small, the surface of the cathode plate will be finely crystallized, and a small amount of electrolyte will be mixed in, which will affect the purity of the cathode copper if it is not cleaned thoroughly later; if the freezing strength of the additive is too large, the surface of the cathode plate will be rough and lack flatness, thus affecting the appearance of the product;

[0012] The additive B is at least one of polyoxypropylene glycol and polytetrahydrofuran diol. The additive B has good acid and high temperature resistance and is not easy to decompose. After being dissolved and added in an appropriate amount and adhering to the cathode surface, the cathode copper has good oxidation resistance.

[0013] The additive C is at least one of polyoxyethylene polyoxypropylene amine ether and polyethylene ether. The additive C does not contain sulfur, which can reduce the content of sulfur as an impurity element in the cathode copper product. At the same time, the adsorption layer on the surface of the plate can prevent the Cu 2+ The disordered and rapid diffusion enhances polarization and refines the grains.

[0014] The above additives can be added once before electrolysis, and then continuously supplemented according to the change of concentration to ensure the concentration of active ingredients.

[0015] The above scheme solves the shortcomings of the existing technology of producing cathode copper with high O and S content and only laboratory test scale scheme. By using a variety of additives, a protective film is formed outside the cathode during the electrolysis process to isolate other impurities, which is suitable for standard industrial production of low-oxygen, low-sulfur high-purity copper, and has the advantages of low cost, easy operation, high purity and continuous production.

[0016] Furthermore, the high-purity cathode copper obtained by the electrolysis is soaked in dilute hydrochloric acid with a temperature of 50-80° C. and a concentration of 5-15%, and then rinsed with distilled water at 60-80° C. and dried with cold air at 20-40° C.

[0017] The high-purity cathode copper after cold air drying is soaked in an anti-oxidation solution for 20 to 60 minutes, wherein the anti-oxidation solution needs to be kept flowing and stirred. After soaking for 1 to 2 hours, it is vacuum packed to obtain a high-purity cathode copper product;

[0018] The anti-oxidation solution is prepared by mixing urea, one or more of hydrazine and its derivatives, glucose and distilled water in a solid-liquid ratio of 1:1:3:(500-1200). The anti-oxidation solution is prepared by stirring for 1-2 hours at a temperature of 60-80°C and then dissolving. This temperature range is the best dissolution range for anti-oxidation substances. Anti-oxidation substances can be fully dissolved and form a dense anti-oxidation film on the surface of the product.

[0019] During the electrolysis process, a 1um thick polytetrafluoroethylene nanofiltration membrane is coated on the anode. In specific operations, the polytetrafluoroethylene nanofiltration membrane can be used to make a nanofiltration membrane bag that matches the size of the anode, which is placed on the anode and sealed with hot melt edges. Polytetrafluoroethylene is a hydrophilic material that can exist stably in a strong acidic environment without affecting the electrolysis reaction process. It can also play a physical isolation role to prevent anode mud from spilling into the electrolyte system.

[0020] During the electrolysis process, the nitrogen introduction rate is 100-200 ml / min to keep the oxygen content in the electrolyte below 5 mg / L. If the nitrogen introduction rate is less than 100 ml / min, the effect of driving out the residual oxygen in the electrolysis system is poor, and a rate greater than 200 ml / min will cause a waste of nitrogen resources. Considering all factors, this range of rates is the best.

[0021] During the electrolysis process, the electrolyte is deeply impurified and filtered to keep the silver content in the electrolyte below 0.001 mg / L and the suspended matter content below 20 mg / L. It can save acid consumption costs with maximum efficiency and solve the problem of electrolyte open circuit. At the same time, it can expand the output of cathode copper and form electrolytic preparation of 5N cathode copper, which is suitable for industrial-scale mass production. In specific implementation, the purified liquid produced by the electrolyte purification system can be circulated with the electrolyte in the electrolytic cell, that is, the purified liquid is continuously added to the electrolytic cell, so that the electrolyte in the electrolytic cell overflows and is discharged again into the electrolyte purification system, thereby ensuring that the electrolyte meets the requirements.

[0022] During the electrolysis process, when the Cu 2+ When the concentration is greater than 50g / L, 1 / 3 of the electrolyte in the electrolytic cell is replaced with new electrolyte. The replaced electrolyte is placed in an electrolytic cell and electrolytically purified using an oxygen-absorbing resin and a high-purity activated carbon package combined column. The oxygen-absorbing resin carrier is an ethylene-vinyl alcohol copolymer, and the active group is a carbon-carbon double bond, which is suitable for use in a strong acidic system.

[0023] In addition, electrolytic anode mud and electrolytic residual electrodes can be mixed to cast ingots. The main copper grade after casting can still reach 99.00%, and can continue to be used as electrolytic anodes to prepare 5N high-purity copper. The recycling of electrolytic anode mud and electrolytic residual electrode ingots can further reduce raw material costs.

[0024] Another object of the present invention is to provide a device for preparing the above-mentioned low-oxygen, low-sulfur, high-purity copper, comprising an electrolytic cell provided with a warm lining, wherein a vertically arranged partition is provided in the electrolytic cell to divide the electrolytic cell into a first cell cavity and a second cell cavity that are connected at the bottom, a sealing cover is provided above the first cell cavity to form a sealing fit with the upper edge of the first cell cavity, an overflow port is provided at the upper position of the cell wall of the second cell cavity, and an air inlet and an air outlet are respectively provided on opposite sides of the sealing cover.

[0025] The upper edge of the first groove cavity and the edge of the sealing cover form an oblique wedge fit, and a rubber sealing pad is provided on the fitting surface between the two.

[0026] Technical effects and advantages of the present invention:

[0027] 1. The present invention solves the problem of easy oxidation of cathode copper by using urea, one or more of hydrazine and its derivatives, glucose and distilled water in combination;

[0028] 2. The present invention can make the cathode copper surface crystallized densely, smooth and flat by using hydrochloric acid, additives A, B and C in combination, and nitrogen is introduced to ensure that the electrolysis is carried out in an oxygen-isolated atmosphere. The oxygen content of the produced 5N cathode copper is less than 3ppm, and the sulfur content is less than 1ppm. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the electrolytic cell of the present invention;

[0030] Figure 2 for Figure 1 Partial enlarged image.

[0031] Figure 3 Schematic diagram of the positional relationship between the anode plate and the cathode plate in the electrolytic cell, wherein a nanofiltration membrane is disposed outside the anode plate. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0033] Example 1

[0034] S1, select 3N cathode copper with main metal copper content greater than 99.90% as electrolytic anode a; titanium plate as electrolytic cathode b, copper sulfate solution as electrolyte (Cu 2+ The concentration of sulfuric acid was controlled at 30 g / L, the concentration of sulfuric acid was controlled at 100 g / L, and the anode and cathode plates were placed in the electrolyte at 25 °C and charged at 100 A / m2 The electrolysis is carried out at a current density of , wherein the electrolysis anode sleeve is a 1um polytetrafluoroethylene hot-melt sealed nanofiltration membrane 60.

[0035] S2, hydrochloric acid, additive A, additive B, and additive C are continuously added during the electrolysis process; wherein, the amount of hydrochloric acid added is 10 mg / L, the amount of additive A added is 3 mg / L, the amount of additive B added is 5 mg / L, and the amount of additive C added is 5 mg / L; hydrochloric acid, additives A, B, and C are added in a continuous, uniform, and continuous manner, and the replenishment frequency is 12 hours / time.

[0036] S3, during the electrolysis process, the electrolytic cell is electrolyzed by introducing a nitrogen atmosphere, and the oxygen isolation treatment is continuously and evenly performed by adjusting the nitrogen introduction rate. The nitrogen introduction rate is 100 ml / min to keep the oxygen content in the electrolyte below 5 mg / L.

[0037] S4, the electrolyte deep impurity removal and precision filtration process is adopted in the electrolysis process, the secondary filter element precision is 1um and 22um respectively, the impurity metal Ag content in the electrolyte is 0.005mg / L, and the suspended matter content is 8mg / L.

[0038] S5, electrolyte Cu 2+ The concentration is 55g / L, and 1 / 3 of the electrolyte is extracted for electrolytic purification;

[0039] S6. The electrolyte precision filtration process is adopted in the electrolytic purification process, the filter element accuracy is 10um, and the suspended matter content in the electrolyte is 3mg / L.

[0040] S7, the cathode copper obtained by the above electrolysis is soaked in dilute hydrochloric acid with a temperature of 60°C and a concentration of 5%, and then rinsed with hot distilled water and dried with cold air to obtain a qualified high-purity copper product; wherein the distilled water rinse water temperature is controlled at 70°C; the cold air drying temperature is 20°C.

[0041] S8. Soak the dried cathode copper product in an anti-oxidation solution for 40 minutes, wherein the anti-oxidation solution needs to be kept flowing and stirred. After soaking for 1 hour, vacuum pack it to obtain a low-oxygen and low-sulfur 5N copper cathode copper product. The anti-oxidation solution is prepared by urea, one or more of hydrazine and its derivatives, glucose and distilled water at a solid-liquid ratio of 1:1:3:500, and the anti-oxidation solution is obtained after stirring at a temperature of 60°C for 1 hour to dissolve.

[0042] Example 2

[0043] S1, select 3N cathode copper with main metal copper content greater than 99.90% as electrolytic anode a; titanium plate as electrolytic cathode b, copper sulfate solution as electrolyte (Cu 2+The concentration was controlled at 40 g / L), the sulfuric acid concentration was controlled at 140 g / L, and the anode and cathode plates were placed in the electrolyte at 35°C and charged at 200 A / m 2 The electrolysis is carried out at a current density of , wherein the electrolysis anode sleeve is a 1um polytetrafluoroethylene hot-melt sealed nanofiltration membrane 60.

[0044] S2, hydrochloric acid, additive A, additive B, and additive C are continuously added during the electrolysis process; wherein, the amount of hydrochloric acid added is 30 mg / L, the amount of additive A added is 10 mg / L, the amount of additive B added is 7 mg / L, and the amount of additive C added is 8 mg / L; hydrochloric acid, additives A, B, and C are added in a continuous, uniform, and continuous manner, and the replenishment frequency is 12 hours / time.

[0045] S3. During the electrolysis process, the electrolytic cell is electrolyzed by introducing a nitrogen atmosphere, and oxygen isolation treatment is continuously and evenly performed by adjusting the nitrogen introduction rate. The nitrogen introduction rate is 150 ml / min to keep the oxygen content in the electrolyte below 5 mg / L.

[0046] S4, the electrolyte deep impurity removal and precision filtration process is adopted in the electrolysis process, the secondary filter element precision is 10um and 20um respectively, the impurity metal Ag content in the electrolyte is 0.0005mg / L, and the suspended matter content is 7mg / L.

[0047] S5, electrolyte Cu 2+ The concentration is 57g / L, and 1 / 3 of the electrolyte is extracted for electrolytic purification.

[0048] S6. The electrolyte precision filtration process is adopted in the electrolytic purification process, the filter element accuracy is 20um, and the suspended matter content in the electrolyte is 5mg / L.

[0049] S7, the cathode copper obtained by the above electrolysis is soaked in dilute hydrochloric acid with a temperature of 65°C and a concentration of 10%, and then rinsed with hot distilled water and dried with cold air to obtain a qualified high-purity copper product; wherein the distilled water rinse water temperature is controlled at 70°C; the cold air drying temperature is 30°C.

[0050] S8. Soak the dried cathode copper product in an anti-oxidation solution for 40 minutes, wherein the anti-oxidation solution needs to be kept flowing and stirred. After soaking for 1.5 hours, vacuum pack it to obtain a low-oxygen and low-sulfur 5N cathode copper product. The anti-oxidation solution is prepared by urea, one or more of hydrazine and its derivatives, glucose and distilled water at a solid-liquid ratio of 1:1:3:900, and the anti-oxidation solution is obtained after stirring at a temperature of 70°C for 1.5 hours to dissolve.

[0051] Example 3

[0052] S1, select 3N cathode copper with main metal copper content greater than 99.90% as electrolytic anode a; titanium plate as electrolytic cathode b, copper sulfate solution as electrolyte (Cu 2+ The concentration was controlled at 50 g / L), the sulfuric acid concentration was controlled at 180 g / L, and the anode and cathode plates were placed in the electrolyte at 45°C and charged at 300 A / m 2 The electrolysis is carried out at a current density of , wherein the electrolysis anode sleeve is a 1um polytetrafluoroethylene hot-melt sealed nanofiltration membrane 60.

[0053] S2, hydrochloric acid, additive A, additive B, and additive C are continuously added during the electrolysis process; wherein, the amount of hydrochloric acid added is 50 mg / L, the amount of additive A added is 20 mg / L, the amount of additive B added is 10 mg / L, and the amount of additive C added is 8 mg / L; hydrochloric acid, additives A, B, and C are added in a continuous, uniform, and continuous manner, and the replenishment frequency is 12 hours / time.

[0054] S3. During the electrolysis process, the electrolytic cell is electrolyzed by introducing a nitrogen atmosphere, and the oxygen isolation treatment is continuously and evenly performed by adjusting the nitrogen introduction rate. The nitrogen introduction rate is 200 ml / min to keep the oxygen content in the electrolyte below 5 mg / L.

[0055] S4, the electrolyte deep impurity removal and precision filtration process is adopted in the electrolysis process, the secondary filter element precision is 10um and 30um respectively, the impurity metal Ag content in the electrolyte is 0.0005mg / L, and the suspended matter content is 9mg / L.

[0056] S5, electrolyte Cu 2+ The concentration is 59g / L, and 1 / 3 of the electrolyte is extracted for electrolytic purification;

[0057] S6. The electrolyte precision filtration process is adopted in the electrolytic purification process, the filter element accuracy is 30um, and the suspended matter content in the electrolyte is 10mg / L.

[0058] S7, the cathode copper obtained by the above electrolysis is soaked in dilute hydrochloric acid with a temperature of 80°C and a concentration of 15%, and then rinsed with hot distilled water and dried with cold air to obtain a qualified high-purity copper product; wherein the distilled water rinse temperature is controlled at 80°C; the cold air drying temperature is 40°C.

[0059] S8. Soak the dried cathode copper product in an anti-oxidation solution for 60 minutes, wherein the anti-oxidation solution needs to be kept flowing and stirred. After soaking for 2 hours, vacuum pack it to obtain a low-oxygen and low-sulfur 5N cathode copper product. The anti-oxidation solution is prepared by urea, one or more of hydrazine and its derivatives, glucose and distilled water at a solid-liquid ratio of 1:1:3:1200, and the anti-oxidation solution is obtained after stirring at a temperature of 80°C for 2 hours to dissolve.

[0060] The test results of the cathode copper products in Examples 1 to 3 were recorded (YS / T 1043-2015, unit: ppm wt). The data are shown in Table 1.

[0061] Table 1 Chemical composition analysis of the products obtained in the examples

[0062]

[0063]

[0064] Through the above tests, it can be seen that the impurity elements of the prepared high-purity copper are well removed, and the oxygen and flow contents are low. In addition, the above process not only has a short process, but is also suitable for industrial-scale mass production.

[0065] The preparation of the above-mentioned high-purity copper is carried out in an electrolytic cell 10 provided with a warm lining, wherein a vertically arranged partition 20 is provided in the electrolytic cell 10 to divide the electrolytic cell 10 into a first cell cavity 11 and a second cell cavity 12 which are connected at the bottom, a sealing cover 30 is provided above the first cell cavity 11 to form a sealing fit with the upper edge of the first cell cavity, an overflow port 40 is provided at the upper position of the cell wall of the second cell cavity 12, and a nitrogen inlet 31 and a nitrogen outlet 32 ​​are respectively provided on opposite sides of the sealing cover 30.

[0066] The partition 20 divides the electrolytic cell 10 into two cells. The first cell 11 with a larger volume is used for electrolysis operation, and the second cell 40 with a smaller volume is used to set the overflow port 40. In this way, when the electrolyte overflows, a vortex will not be formed around the anode and the cathode to cause electrolyte fluctuations and affect the electrolysis process; and it is only necessary to maintain the nitrogen atmosphere above the first cell 11, and set the overflow port 40 outside the nitrogen atmosphere range, which also avoids the discharge of nitrogen from the overflow port 40, resulting in a large amount of nitrogen escape and waste.

[0067] The upper edge of the first groove cavity 11 and the edge of the sealing cover 30 form an oblique wedge fit, and a rubber sealing pad 50 is provided on the fitting surface between the two. Figure 2 As shown, the sealing cover 30 uses its own weight to compress the rubber sealing pad (polytetrafluoroethylene rubber pad) below to ensure complete sealing and maintain a nitrogen atmosphere above the electrolyte to isolate oxygen, avoid bubbles in the electrolyte that affect the quality of the cathode copper, and blow nitrogen into the electrolytic cell from one side, while the other side exhausts the acid mist generated by electrolysis and the excess nitrogen blown in.

[0068] Since the electrolytic cell 10 is relatively large in size, the sealing cover 30 (which may be made of polytetrafluoroethylene) is also relatively large in size, and lifting or lowering it requires the cooperation of multiple people. Therefore, it is necessary to provide multiple handles on the sealing cover 30 for easy operation.

[0069] The nitrogen inlet pipe can extend inward from the nitrogen inlet port 31, and a plurality of small nitrogen outlets can be provided at the tail section to prevent a large influx of nitrogen gas from causing electrolyte fluctuations and affecting the electrolysis process.

Claims

1. A method for preparing low-oxygen, low-sulfur, high-purity copper, characterized in that: A copper plate with a copper content greater than 99.90% is used as the anode, a stainless steel plate or a titanium plate is used as the cathode, and a copper sulfate solution is used as the electrolyte. The current density is 100 to 300 A / m at 25 to 45 °C. 2 , electrolysis is carried out under the protection of nitrogen atmosphere; in the copper sulfate solution: Cu 2+ Concentration 30-50g / L, sulfuric acid concentration 100-180g / L; During the electrolysis process, hydrochloric acid, additive A, additive B, and additive C are added and continuously replenished to maintain the concentration of hydrochloric acid in the electrolyte at 10-50 mg / L, the concentration of additive A at 3-20 mg / L, the concentration of additive B at 5-10 mg / L, and the concentration of additive C at 5-10 mg / L; after the electrolysis is completed, high-purity cathode copper is obtained; The additive A is a composite active protein extracted from animals, with a molecular weight of 10-25 kDa and a freezing strength of 100-120; The additive B is at least one of polyoxypropylene glycol and polytetrahydrofuran diol; The additive C is at least one of polyoxyethylene polyoxypropylene amine ether and polyethylene ether.

2. The method for preparing low-oxygen, low-sulfur, high-purity copper according to claim 1, characterized in that: The high-purity cathode copper obtained by the electrolysis is soaked in dilute hydrochloric acid with a temperature of 50-80°C and a concentration of 5-15%, and then rinsed with distilled water at 60-80°C and dried with cold air at 20-40°C.

3. The method for preparing low-oxygen, low-sulfur, high-purity copper according to claim 2, characterized in that: The high-purity cathode copper after cold air drying is soaked in an anti-oxidation solution for 20 to 60 minutes, wherein the anti-oxidation solution needs to be kept flowing and stirred. After soaking for 1 to 2 hours, it is vacuum packed to obtain a high-purity cathode copper product; The anti-oxidation solution comprises urea, one or more of hydrazine and its derivatives, glucose and distilled water in a solid-liquid ratio of 1:1:3:(500-1200).

4. The method for preparing low-oxygen, low-sulfur, high-purity copper according to claim 1, characterized in that: During the electrolysis process, a 1um thick polytetrafluoroethylene nanofiltration membrane is coated on the outside of the anode.

5. The method for preparing low-oxygen, low-sulfur, high-purity copper according to claim 1, characterized in that: During the electrolysis process, the nitrogen introduction rate is 100-200 ml / min to keep the oxygen content in the electrolyte below 5 mg / L.

6. The method for preparing low-oxygen, low-sulfur, high-purity copper according to claim 1, characterized in that: During the electrolysis process, when the Cu 2+ When the concentration is greater than 50g / L, replace 1 / 3 of the electrolyte in the electrolytic cell with new electrolyte.

7. The method for preparing low-oxygen, low-sulfur, high-purity copper according to claim 6, characterized in that: The replaced electrolyte is placed in an electrolytic cell and electrolytically purified using an oxygen absorbing resin and a high-purity activated carbon packaged composite column, wherein the oxygen absorbing resin carrier is an ethylene-vinyl alcohol copolymer.

8. The method for preparing low-oxygen, low-sulfur, high-purity copper according to claim 1, characterized in that: During the electrolysis process, the electrolyte is deeply cleaned and filtered to keep the silver content in the electrolyte below 0.001 mg / L and the suspended matter content below 20 mg / L.

9. A device for preparing the low-oxygen, low-sulfur, high-purity copper according to any one of claims 1 to 7, characterized in that: The invention comprises an electrolytic cell (10) provided with a warm lining, wherein a vertically arranged partition (20) is provided in the electrolytic cell (10) to divide the electrolytic cell (10) into a first cell cavity (11) and a second cell cavity (12) which are connected at the bottom, a sealing cover (30) is provided above the first cell cavity (11) to form a sealing fit with the upper edge of the first cell cavity, an overflow port (40) is provided at the upper position of the cell wall of the second cell cavity (12), and a nitrogen inlet (31) and a nitrogen outlet (32) are respectively provided on opposite sides of the sealing cover (30).

10. The device for preparing low-oxygen, low-sulfur, high-purity copper according to claim 9, characterized in that: The upper edge of the first groove cavity (11) and the edge of the sealing cover (30) form an oblique wedge fit, and a rubber sealing pad (50) is provided on the fitting surface between the two.

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