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CN-121976254-A - Production method of high-purity electrolytic copper powder

CN121976254ACN 121976254 ACN121976254 ACN 121976254ACN-121976254-A

Abstract

The invention discloses a production method of high-purity electrolytic copper powder, which comprises the steps of preparing an acidic electrolyte by using copper sulfate and sulfuric acid, adding a small amount of chloride ions, and meanwhile, according to the technical requirement of copper powder, adding no or a small amount of auxiliary agents into the solution, ensuring that the total sum of cationic impurities of the electrolyte is less than or equal to 10ppm, enabling a diffusion boundary layer on the surface of a cathode to be extremely thin under the condition that a cathode generates a strong shearing force when rotating at a high speed, and enabling copper ions to be 'flushed' to the surface of the cathode at the extremely high speed, thereby realizing extremely strengthening of mass transfer. The system can operate at a current density far higher than that of the traditional method, so that the preparation from solution to high-quality copper powder is directly finished, the reaction rate is extremely high, and the productivity of equipment is improved. And the powder is stripped from the cathode and coupled in a device, so that the flow is simplified, the tank voltage is reduced, side reactions such as hydrogen gas precipitation and the like are inhibited, the current efficiency is improved, the running cost is reduced, and meanwhile, the consistency and the reliability of products are ensured.

Inventors

  • ZHOU ANBANG
  • SUN FENGLING

Assignees

  • 江苏木林升高新材料有限公司

Dates

Publication Date
20260505
Application Date
20260212

Claims (10)

  1. 1. The production method of the high-purity electrolytic copper powder is characterized by comprising the following steps of: Preparing electrolyte, namely preparing acidic electrolyte by using copper sulfate and sulfuric acid, and adding a small amount of chloride ions, wherein no or a small amount of auxiliary agent is added into the solution according to the technical requirement of copper powder, so that the total cationic impurity of the electrolyte is ensured to be less than or equal to 10ppm; step 2, cyclone liquid inlet, namely, electrolyte enters a cylindrical static pressure steady flow cavity from the upper part of the reactor, wherein an electrolyte inlet is designed to be in a tangential direction, so that the electrolyte generates cyclone in the reactor; Step 3, the cathode rotates at a high speed, and then electrolyte enters a reaction zone between the cathode and the anode in a rotating balance way from the static pressure steady flow cavity; Controlling the current density of the anode within the range of 10-50A/dm < 2 >, carrying out high-current density electrolysis, and when a servo motor drives a rotor to rotate at a high speed, bearing huge centrifugal force (namely supergravity) by electrolyte near the surface of a cathode, wherein a diffusion boundary layer on the surface of the cathode becomes extremely thin under strong shearing force, copper ions can 'rush to' the surface of the cathode at an extremely high speed, so that the intensified mass transfer is realized, and meanwhile, the shortage of ions cannot occur under the action of an electric field; copper powder stripping, namely reducing copper ions into copper powder on the surface of a cathode, separating out hydrogen bubbles at the same time, and performing strong shearing action generated by supergravity, so that not only can the copper powder just generated on the cathode be stripped instantaneously and the separated out hydrogen bubbles, but also the surface of the cathode can be kept in a high-efficiency reaction state all the time; And 6, collecting copper powder, namely, under the conditions of cyclone impact and high gravity and strong shearing, throwing off a cathode at a high speed, collecting copper powder to the center of a reactor, and falling into the bottom of a conical collecting tank, forcibly flowing copper powder out of a reaction area along with electrolyte, and feeding the copper powder into a bag filter for solid-liquid separation, washing the collected copper powder to remove residual electrolyte, and drying to obtain the final high-purity electrolytic copper powder.
  2. 2. The method of producing high purity electrolytic copper powder according to claim 1, wherein in step 1, the prepared electrolyte is fed into a liquid storage tank, a circulation and heat exchange system is started, preheated to 30-50 ℃ and kept at a constant temperature, and purified by a circulation filter and ion exchange resin until the electrolyte meets the process purity requirement.
  3. 3. The method of claim 1, wherein in the step 2, the static pressure and steady flow cavity is made of polypropylene or polytetrafluoroethylene, and has good sulfuric acid corrosion resistance and good insulating property, and a deflector or a spiral flow passage can be arranged in the cavity to further stabilize the rotational flow and avoid the phenomenon of electrolyte short circuit or vortex.
  4. 4. The method of producing high purity electrolytic copper powder according to claim 1, wherein in step 3, the cathode substrate is made of titanium, the specific gravity is controlled to be 1.05-1.1 after the counter weight, and the surface can be subjected to sand blasting or etching treatment to increase microscopic roughness, thereby facilitating nucleation and stripping of copper powder.
  5. 5. The method of producing high purity electrolytic copper powder according to claim 1, wherein in step 3, the upper portion of the cathode is provided with a brush device made of silver-graphite composite material, which ensures stable conduction of current even at high rotation speeds.
  6. 6. The method of producing high purity electrolytic copper powder according to claim 1, wherein in step 3, the anode is cylindrical and is provided with a flange for installation, and the surface is coated with a noble metal catalytic layer having a thickness of about 5-10 μm, thereby improving oxygen evolution efficiency and stability.
  7. 7. The method for producing high-purity electrolytic copper powder according to claim 1, wherein in the step 3, the servo motor is provided with an encoder and a PLC to be linked, so that the accurate control of the rotating speed is realized, the soft start and overload protection functions are realized, meanwhile, the servo motor is connected with a rotor main shaft by a flexible coupling, so that the vibration transmission is reduced, and the running stability is improved.
  8. 8. The method of claim 1, wherein in step 4, heat of the cathode and the anode is carried out of the electrolytic reaction zone by the electrolyte during the reaction process, so as to maintain the temperature of the reaction system stable.
  9. 9. The method of producing high purity electrolytic copper powder according to claim 1, wherein in step 6, the inner wall of the cone collecting tank may be lined with fluoroplastic or rubber to prevent copper powder from adhering, and the bag filter is a polyester or polypropylene filter bag and supports back blowing to remove ash automatically.
  10. 10. The method for producing high-purity electrolytic copper powder according to claim 1, wherein in the step 6, wet copper powder is washed with deionized water and ethanol in sequence, the drying process is performed in vacuum or inert atmosphere at a temperature not higher than 80 ℃ to prevent oxidation and agglomeration, and a pneumatic butterfly valve or plunger valve is arranged at the outlet to realize intermittent or continuous discharging and is connected with a nitrogen protection system to prevent copper powder oxidation.

Description

Production method of high-purity electrolytic copper powder Technical Field The invention relates to the technical field of electrolytic copper powder processing, in particular to a production method of high-purity electrolytic copper powder. Background The traditional copper powder production method generally adopts an electrolytic deposition method, namely, copper ions are reduced and deposited on the surface of a cathode to form copper powder by the action of direct current in an electrolytic tank, and the copper powder production method has a plurality of inherent limitations: The electrolytic cell structure and the electrochemical principle limit the current efficiency is generally low, a considerable part of electric energy is consumed in side reactions such as decomposition and hydrogen evolution of water and the like and the system heats in the electrolytic process, but is not effectively used for copper deposition, so that the energy consumption is high, meanwhile, sulfuric acid mist volatilized in the electrolytic process seriously corrodes workshop equipment, and the long-term exposure can harm the respiratory system of operators, so that a powerful ventilation and waste gas purification device is required to be matched, the energy consumption is further increased, the anode mud generated in the anodic dissolution process is complex in composition and often contains toxic heavy metals such as arsenic, antimony and bismuth, the method belongs to dangerous solid waste, the treatment process is complex, and the environment leakage risk exists. The electrolytic reaction rate is limited by the ion mass transfer speed, the deposition period is long, intermittent stripping of cathode copper powder is often required, the copper powder yield per unit equipment volume is low, the production efficiency is limited, and if the electrolyte is not thoroughly purified, impurity elements in the anode can be co-deposited along with copper ions, so that the purity of the copper powder is reduced, and the subsequent application performance is affected. The traditional electrolytic copper powder is in a dendritic structure, is favorable for compression molding, but has low loose density and poor fluidity, so that the application in a precise molding process is limited, meanwhile, the powder particle size distribution is wide, the proportion of fine powder to coarse powder is difficult to precisely regulate and control, and the consistency and reliability of the product are difficult to ensure. Therefore, a production method of high-purity electrolytic copper powder is provided to solve the problem. Disclosure of Invention The invention aims to provide a production method of high-purity electrolytic copper powder, which solves the problems that a large amount of circulating cooling water is needed in the traditional electrolytic copper powder production process, the electric energy operation cost is high, toxic and harmful waste gas substances are generated, and the consistency and reliability of products are difficult to ensure. In order to achieve the purpose, the invention provides the following technical scheme that the production method of the high-purity electrolytic copper powder comprises the following steps: Preparing electrolyte, namely preparing acidic electrolyte by using copper sulfate and sulfuric acid, and adding a small amount of chloride ions, wherein no or a small amount of auxiliary agent is added into the solution according to the technical requirement of copper powder, so that the total cationic impurity of the electrolyte is ensured to be less than or equal to 10ppm; step 2, cyclone liquid inlet, namely, electrolyte enters a cylindrical static pressure steady flow cavity from the upper part of the reactor, wherein an electrolyte inlet is designed to be in a tangential direction, so that the electrolyte generates cyclone in the reactor; Step 3, the cathode rotates at a high speed, and then electrolyte enters a reaction zone between the cathode and the anode in a rotating balance way from the static pressure steady flow cavity; Controlling the current density of the anode within the range of 10-50A/dm < 2 >, carrying out high-current density electrolysis, and when a servo motor drives a rotor to rotate at a high speed, bearing huge centrifugal force (namely supergravity) by electrolyte near the surface of a cathode, wherein a diffusion boundary layer on the surface of the cathode becomes extremely thin under strong shearing force, copper ions can 'rush to' the surface of the cathode at an extremely high speed, so that the intensified mass transfer is realized, and meanwhile, the shortage of ions cannot occur under the action of an electric field; copper powder stripping, namely reducing copper ions into copper powder on the surface of a cathode, separating out hydrogen bubbles at the same time, and performing strong shearing action generated by supergravity, so that not only can the copper powder j