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

Cu electrorefining using a low-grade copper anode is desirable from the standpoint of electric power savings. electrolysis was carried out in an unagitated sulfate solution with anode, and effect impurity ions additives on passivation investigated. The time when firstly occurs shortened significantly containing 0.596 mol·dm−3 Ni2+ as somewhat As5+(0.053 mol·dm−3) or Bi3+(0.0005 ions. Sn2+(0.0004 As3+(0.053 slightly decreased to passivation, but Sb3+(0.004 did not. viscosity coefficient increased were added solution, while diffusion Cu2+ decreased. compound As–Sb–O As–Bi–O system formed slime which seemed increase compactness slime. longer thiourea-free concentration thiourea 0.525 2.24 mmol·dm−3. constant solutions 0 1.13 mmol·dm−3 Cl− ions, above Cu–Cl at upper area slime, promoted passivation.