China Nonferrous Metallurgy

Aiming at the problems of complex process， high cost and difficulty in large-scale production of existing high-purity copper preparation methods （recycled copper smelting process and vacuum distillation process）， this paper adopts the method of wrapping filter screen on cathode plates proposed by the research group to prepare highpurity copper. Numerical simulation of the copper electrolytic refining process is carried out using COMSOL Multiphysics software， and verification experiments are conducted based on the simulation results. The simulation results show that after wrapping filter screen cloth on the cathode plate， the overall distribution of Cu2 ? concentration in the electrolytic cell is relatively uniform， with a slightly higher concentration at the tank bottom； the copper depletion zone is no longer limited to the cathode surface， but extends to the entire area between the filter screen and the cathode plate； the region between the filter screen and the cathode plate is not affected by forced convection， and a clockwise circulation upward along the cathode plate and downward along the inner side of the filter screen is formed driven by the density gradient of the electrolyte； the current density on the cathode plate surface varies greatly， with the current density at the bottom increased by 156% compared with that at the top. Dendritic nodules appear on the surface of electrolytic cathode copper at a current density of 186 A/m2， and the appropriate current density is 93 A/m2. The verification experiments show that conventional electrolysis under the conditions of 1 μm filter screen pore size and 93 A/m2 current density can significantly improve the purity of cathode copper； the concentration of impurity particles in the top area of the cathode copper plate surface is lower than that in the bottom area （except for Mo element）； by comparing the composition results of the top area of the prepared cathode copper plate with the national standard for High-Purity Copper， only the Ag element content is higher than the upper limit of the national standard， and the purity reaches 99. 99958356%. In the future， pulse current or periodic reverse current electrolysis， or the addition of leveling agents can be attempted to obtain a flatter deposition layer； an appropriate amount of hydrochloric acid can be added to the electrolyte in advance to remove Ag， so as to further improve the purity of cathode copper. The research results can provide theoretical and technical references for the large-scale production of high-purity copper.