Effect of Impurity Ions and Additives in Solution of Copper Electrorefining on the Passivation Behavior of Low-Grade Copper Anode

Kohei Mori, Yuta Yamakawa, Satoshi Oue, Yu Ki Taninouchi, Hiroaki Nakano

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Cu electrorefining using a low-grade copper anode is desirable from the standpoint of electric power savings. Cu electrolysis was carried out in an unagitated sulfate solution with a low-grade copper anode, and the effect of impurity ions and additives in the solution on the passivation of the anode was investigated. The time when anode passivation firstly occurs shortened significantly in a solution containing 0.596 mol·dm13 of Ni2+ ions as impurity and shortened somewhat in a solution containing As5+(0.053 mol·dm13) or Bi3+(0.0005 mol·dm13) ions. Sn2+(0.0004 mol·dm13) and As3+(0.053 mol·dm13) ions slightly decreased the time to passivation, but Sb3+(0.004 mol·dm13) ions did not. The viscosity coefficient of the solution increased when the 0.596 mol·dm13 of Ni2+ ions were added to the solution, while the diffusion coefficient of Cu2+ ions decreased. The compound of the AsSbO or AsBiO system was formed in anode slime when the As5+(0.053 mol·dm13) or Bi3+(0.0005 mol·dm13) ions were added to the solution, which seemed to increase the compactness of slime. The time to passivation was slightly longer in thiourea-free solution but shortened when the concentration of thiourea was increased from 0.525 to 2.24 mmol·dm13. The time to passivation was constant in solutions containing 0 to 1.13 mmol·dm13 of Cl1 ions, but significantly decreased as the concentration of Cl1 ions increased above 1.13 mmol·dm13. Cl1 ions formed CuCl at the upper area of anode slime, which increased the compactness of slime and promoted the passivation.

Original languageEnglish
Pages (from-to)242-251
Number of pages10
JournalMaterials Transactions
Volume64
Issue number1
DOIs
Publication statusPublished - 2023

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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