Method for producing high-quality copper oxide powder by taking copper sponge as raw material

Abstract

The invention discloses a method for producing high-quality copper oxide powder by taking sponge copper as a raw material, and the copper oxide powder prepared by the method has stable physical and chemical indexes and can be used in industries such as fireworks, glass, enamel, ceramics, paint, printing ink, coatings and the like. The copper oxide powder is high-quality copper oxide powder prepared by taking sponge copper produced by electrolytic copper removal of a nickel electrolyte as a raw material through hot water washing, high-temperature oxygen-enriched normal-pressure leaching, electrolytic impurity removal powder preparation, washing, drying pre-oxidation, calcination crushing and screening. According to the method for preparing the copper oxide powder, resource utilization of high-impurity-content spongy copper is achieved, impurity removal is achieved by strictly controlling the electrolytic current density after cleaning and leaching, copper powder particles with the average particle size of 30 micrometers are produced through electrolysis, and soluble salts and sulfate radicals in the copper powder particles are removed through hot water washing and filtering; and the copper oxide powder with uniform particle size and stable grade is finally produced through low-temperature drying pre-oxidation and subsequent high-temperature calcination.

Description

Technical Field

[0001] The invention belongs to the field of powder metallurgy manufacturing, and specifically relates to a method for producing high-quality copper oxide powder by taking sponge copper as raw material. Background Art

[0002] Copper oxide (CuO) is a black metal oxide of copper, slightly amphoteric and slightly hygroscopic. The density is 6.3~6.9g / cm, and the melting point is 1326℃. It is insoluble in water and ethanol, soluble in acid, ammonium chloride and potassium cyanide solution, slowly dissolved in ammonia solution, and can react with strong alkali. It is mainly used in the production of artificial silk, ceramics, glaze and enamel, batteries, petroleum desulfurizers, pesticides, and also for hydrogen production, catalysts, green glass, etc. It is one of the non-ferrous metal powders with the largest production and consumption in my country.

[0003] Mechanical crushing and liquid phase method are the most commonly used methods for preparing copper oxide powder in laboratories and industries. The mechanical crushing method generally uses copper rice and other single copper particles to form fine copper powder particles after repeated oxidation and crushing. The raw materials of this method are relatively simple and the price is relatively high. The preparation steps of the liquid phase method are to select one or more soluble copper salts, prepare them into solutions according to the material composition, make each element in ionic or molecular state, and then select a suitable precipitant or use evaporation, sublimation, hydrolysis and other operations to make copper ions uniformly precipitate or crystallize. Finally, the precipitation or crystallization is heat treated to obtain copper oxide powder. This method faces huge pressure on wastewater treatment and environmental protection. Summary of the invention

[0004] Aiming at the problems of high raw material cost of existing mechanical crushing method and high wastewater treatment pressure of liquid phase method, this method provides a method for producing high-quality copper oxide powder using sponge copper as raw material. The scheme is electrolytic purification and impurity removal and powder making. In addition to sponge copper, it can be widely used in a variety of solid and liquid copper raw materials. The electrolyte can be reused as leaching liquid, and the washing water can be used to supplement the electrolyte to form a system cycle. The external water discharge is greatly reduced, and the production system operation is more economical and efficient.

[0005] To this end, the present invention adopts the following technical solutions: Step 1: Hot water washing: The sponge copper is washed with high-temperature water slurry to remove the metal impurities such as ionic nickel, and then centrifuged and dried for later use. The washing water temperature is 40-50°C; Step 2: Normal pressure oxygen-enriched leaching: After washing, the sponge copper is added to a dilute sulfuric acid solution with a temperature of 70-90°C and a concentration of 150-180 g / l, and compressed air is introduced into the solution under continuous stirring. The solution is leached under normal pressure to remove Cu 2+ Concentration 70-80 g / l; Step 3: Filtration: Purification filtration. After leaching, the copper sulfate solution is filtered by a plate and frame filter press and a 5-micron pore filter press, and then filtered and clarified for later use; Step 4: Electrolytic purification and powder making. Adjust the current according to the copper metal electrode potential and control the current density at 2000-2200A / ㎡ for electrolytic purification and powder making. After leaching, the copper sulfate solution is slowly and continuously injected into the electrolyte to supplement the copper ions. 2+ Control it at 10-16g / l, brush powder regularly to control the particle size of copper powder, and the particle size is controlled at about 30μm; Step 5: Washing: Pour the copper powder slurry into a special washing equipment, wash it 4-5 times with 50℃ tap water, and then filter it to dry. 2- Content less than 0.05%; Step 6 Drying and pre-oxidation: The washed copper powder particles are dried and oxidized at low temperature by passing oxygen through the filter, and the drying temperature is 300°C; Step 7: Calcination and crushing: The dried pre-oxidized powder is calcined again at high temperature, and the calcination temperature is stabilized at 800°C, and the cuprous oxide content is less than 0.2%; Step 8 Screening and packaging: Screen and grade the copper oxide powder according to demand, and the screening rate of the product should be ≥99% in one inspection.

[0006] The beneficial effects of the present invention are: high-quality copper oxide powder is produced from impure sponge copper raw materials, soluble salt impurities are removed by washing, copper is precipitated into fine copper powder particles by adjusting the electrode potential in an electrolytic manner, and stable copper oxide powder is formed by drying, oxidizing and roasting. Microbubble high-temperature and normal-pressure leaching effectively avoids the risk of introducing impurities by adding strong oxidants, and the drying pre-oxidation method avoids the difficulty of subsequent treatment caused by sintering of materials during the roasting process. DETAILED DESCRIPTION

[0007] The following specific examples further illustrate the production process of high-quality copper oxide powder: Example 1 Step 1: Take 200kg of sponge copper and add it to the slurry tank, inject tap water and heat it to 40℃, start stirring and slurrying for 1 hour, use a centrifuge to separate the solid and liquid, filter and wash it again with clean tap water for 3 minutes, release the material and set it aside, and the washing liquid can be reused for slurrying; Step 2: Add the washed sponge copper into the copper dissolver, inject 168g / l dilute sulfuric acid solution, heat to 85℃, continue to introduce microbubble compressed air, stir and leach for 8 hours until Cu 2+ Concentration 73g / l, turn off steam, compressed air and stirring and let the solution stand to clarify; Step 3: The clarified solution is filtered through a plate and frame filter press and a precision filter, and transferred to a storage tank for standby use; Step 4: Slowly and continuously inject the filtered copper sulfate solution into the electrolysis system for electrolytic purification and impurity removal. 2+Concentration 12.4g / l, current density 2000 A / ㎡, de-powdering cycle 30min; Step 5: The copper powder produced by electrolysis is transferred to a special powder washing equipment and washed 5 times with 50℃ tap water, with a solid-liquid ratio of 1:5. After washing, the copper powder SO4 2- Content 0.019%; Step 6: The washed copper powder is evenly arranged in a belt drying furnace for ventilation and drying and pre-oxidation at a drying temperature of 300°C for 3 hours; Step 7: After drying and pre-oxidation, the copper oxide powder is added into a dynamic calcining furnace for oxidation roasting. The roasting temperature is 800°C and the roasting time is 12 hours. The cuprous oxide content of the material after roasting is 0.1%; Step 8: After roasting, the material is sieved through a 200-mesh sieve, and the screening rate is 99.5% after one inspection. Table 1- Main technical indicators of copper oxide powder Example 2 Step 1: Take 200kg of sponge copper and add it to the slurry tank, inject tap water and heat it to 50℃, start stirring and slurrying for 1 hour, use a centrifuge to separate the solid and liquid, filter and wash it again with clean tap water for 3 minutes, release the material and set it aside, and the washing liquid can be reused for slurrying; Step 2: Add the washed sponge copper into the copper dissolver, inject 173g / l dilute sulfuric acid solution, heat to 82℃, continue to introduce microbubble compressed air, stir and leach for 8 hours until Cu 2+ Concentration 79g / l, turn off steam, compressed air and stirring and let the solution stand to clarify; Step 3: The clarified solution is filtered through a plate and frame filter press and a precision filter, and transferred to a storage tank for standby use; Step 4: Slowly and continuously inject the filtered copper sulfate solution into the electrolysis system for electrolytic purification and impurity removal. 2+ Concentration 11.7g / l, current density 2000 A / ㎡, de-powdering cycle 30min; Step 5: The copper powder produced by electrolysis is transferred to a special powder washing equipment and washed 5 times with 46°C tap water, with a solid-liquid ratio of 1:5. After washing, the copper powder SO4 2- Content 0.021%; Step 6: The washed copper powder is evenly arranged in a belt drying furnace for ventilation and drying and pre-oxidation at a drying temperature of 300°C for 3 hours; Step 7: After drying and pre-oxidation, the copper oxide powder is added into a dynamic calcining furnace for oxidation roasting. The roasting temperature is 800°C and the roasting time is 12 hours. The cuprous oxide content of the material after roasting is 0.1%; Step 8: After roasting, the material is sieved through a 200-mesh sieve, and the screening rate is 99.5% after one inspection. Table 2- Main technical indicators of copper oxide powder Example 3 Step 1: Take 250kg of sponge copper and add it to the slurry tank, inject tap water and heat it to 43°C, start stirring and slurrying for 1 hour, use a centrifuge to separate the solid and liquid, filter and wash it again with clean tap water for 3 minutes, release the material and set it aside, and the washing liquid can be reused for slurrying; Step 2: Add the washed sponge copper into the copper dissolver, inject 154g / l dilute sulfuric acid solution, heat to 85℃, continue to introduce microbubble compressed air, stir and leach for 9 hours until Cu 2+ Concentration 71g / l, turn off steam, compressed air and stirring and let the solution stand to clarify; Step 3: The clarified solution is filtered through a plate and frame filter press and a precision filter, and transferred to a storage tank for standby use; Step 4: Slowly and continuously inject the filtered copper sulfate solution into the electrolysis system for electrolytic purification and impurity removal. 2+ Concentration 14.1g / l, current density 2000 A / ㎡, de-powdering cycle 30min; Step 5: The copper powder produced by electrolysis is transferred to a special powder washing equipment and washed 5 times with 46°C tap water, with a solid-liquid ratio of 1:5. After washing, the copper powder SO4 2- Content 0.017%; Step 6: The washed copper powder is evenly arranged in a belt drying furnace for ventilation and drying and pre-oxidation at a drying temperature of 300°C for 3 hours; Step 7: After drying and pre-oxidation, the copper oxide powder is added into a dynamic calcining furnace for oxidation roasting. The roasting temperature is 800°C and the roasting time is 12 hours. The cuprous oxide content of the material after roasting is 0.1%; Step 8: The calcined material is sieved through a 200-mesh sieve, and the screening rate is 99.1% after one inspection. Table 3- Main technical indicators of copper oxide powder

Claims

1. A method for producing high-quality copper oxide powder using sponge copper as raw material, characterized in that: The following steps are involved: Step 1: Hot water washing: After the sponge copper is slurried, it is washed with hot water and centrifuged to remove the residual ionic nickel and some water-soluble substances in the sponge copper; Step 2: atmospheric pressure oxygen-enriched leaching: the washed sponge copper is added into a heated dilute sulfuric acid solution, and oxygen is passed through the stirring leaching process to make the concentration of the copper sulfate solution reach the target concentration; Step 3: Filtration: Filter the leached copper sulfate solution to remove solid particles and other insoluble substances; Step 4: Electrolysis and impurity removal: the filtered solution is added into the electrolysis system according to the flow rate, and the current density is controlled according to the process requirements to produce copper powder and remove impurities; Step 5: washing: washing the produced electrolytic copper powder particles with water in a washing device, and filtering out the water after washing; Step 6 Drying and pre-oxidation: The electrolytic copper powder particles after washing and filtration are dried and pre-oxidized using air from a belt drying furnace; Step 7: Calcination and crushing: The dried copper powder particles are calcined and crushed again at high temperature to form copper oxide powder particles; Step 8 Screening and packaging: The calcined copper oxide powder is screened and packaged as required.

2. The method for producing high-quality copper oxide powder using sponge copper as raw material according to claim 1, characterized in that: In step 1, the washing water temperature is adjusted, and the stirring time of the sponge copper slurry is controlled to ensure that the nickel-containing salts and soluble substances contained in the lumps and agglomerated particles are dissolved in the washing water. The washing water temperature is within the range of 40 to 50° C., and the water content of the material after slurry washing and filtration is ≤12%.

3. The method for producing high-quality copper oxide powder using sponge copper as raw material according to claim 1, characterized in that: In step 2, the washed sponge copper is leached in dilute sulfuric acid under normal pressure, oxygen-rich and high temperature conditions, the concentration of dilute sulfuric acid is 150-180 g / l, the leaching temperature is 70-90° C., and microbubble compressed air is continuously introduced during the leaching process to ensure its oxidation leaching efficiency, and slag is discharged every 3-4 leaching cycles.

4. The method for producing high-quality copper oxide powder using sponge copper as raw material according to claim 1, characterized in that: In step 3, the sponge copper leaching solution is filtered by a plate and frame filter press and a precision filter, the pore size of the filter membrane tube is ≤5 μm, and after filtration, it is buffered and allowed to settle again before being used for the next process.

5. The method for producing high-quality copper oxide powder using sponge copper as raw material according to claim 1, characterized in that: In step 4, according to the different principles of different metal electrode potentials, the electrolyte Cu 2+ and acid concentration, Cu 2+ The concentration is 10-16 g / l. The current density is controlled to 2000-2200 A / ㎡ according to the size of the anode and cathode plates. The copper ions in the electrolyte are electrolyzed and converted into single copper particles to achieve effective separation from other metal impurities. During the electrolysis process, the copper powder particles are regularly separated from the cathode plate surface and the particle size of the copper powder particles is controlled to be 25-35 μm.

6. The method for producing high-quality copper oxide powder using sponge copper as raw material according to claim 1, characterized in that: In step 5, the copper powder particles produced by electrolysis are washed and filtered with 45-55°C tap water. After washing and filtering, SO4 2- The content is less than 0.05% and the moisture content is less than 10%.

7. The method for producing high-quality copper oxide powder using sponge copper as raw material according to claim 1, characterized in that: In step 6, the washed and filtered copper powder particles are dried and pre-oxidized by passing compressed air at a temperature of 280 to 320° C. in a belt drying furnace to prevent subsequent sintering of the single copper powder particles.

8. The method for producing high-quality copper oxide powder using sponge copper as raw material according to claim 1, characterized in that: In step 7, the dried pre-oxidized copper powder is calcined at a high temperature of 750-850° C. to control the cuprous content therein to less than 0.1%.

9. The method for producing high-quality copper oxide powder using sponge copper as raw material according to claim 1, characterized in that: In step 8, the calcined and oxidized copper oxide powder is graded and output as products using a screening machine according to demand, and the screening rate of the product is ≥99% in one inspection.

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