A novel method for rapid and highly selective removal of arsenic from copper electrolyte using zirconium salts

Abstract

Copper electrolytes generally contain high concentrations of arsenic (As), which is very harmful in copper electrolytic production. In this paper, a zirconium salt, which selectively precipitated arsenic, was added to the electrolyte to realize rapid and efficient arsenic removal. The effects of zirconium salt addition, the reaction temperature, reaction time and different electrolytes on arsenic removal were systematically investigated, the concentration equilibrium curves for As and Zr were established at different temperatures, the effects of residual zirconium ions on copper electrolysis were evaluated, and a theoretical study of the arsenic removal process was carried out. The results showed that with the optimal conditions for arsenic precipitation, 85.41 % of the As was removed from the industrial electrolyte, and the As concentration in the electrolyte was decreased to 1.41 g/L. Regeneration of the precipitates was achieved in NaOH solutions, and the regenerated precipitates exhibited efficient As removal. The As–Zr reactions followed a third-order kinetics model, and the apparent activation energy was 36.42 kJ/mol. Furthermore, the As–Zr reaction pathway, transition state structure and microscopic valence bonding changes were investigated with density functional theory (DFT). This research provides a promising method for processing copper electrolyte with high contents of As.