Selective Recovery of Bismuth in Copper Electrolyte Through Coprecipitation Method and Its Mechanism

Bismuth (Bi) is a scarce and valuable metal, which is associated with copper minerals and condensed in copper electrolyte during electrorefining process. Therefore, the recovery of Bi from the copper electrolyte is of great significance. In this work, barium carbonate (BaCO 3 ) was used to in situ form barium sulfate (BaSO 4 ) and recover Bi(III) from copper electrolyte selectively through coprecipitation method. The concentrations of coexisting ions, such as Cu 2+ , Ni 2+ , Sb(III, V), and As(III, V), are relatively stable during the coprecipitation process, indicating a certain selectivity for Bi(III). One-step desorption method was used to extract Bi from the precipitate. The results show that Bi(III) exists in the coprecipitation in two forms; dissolved into the lattice and adsorbed on the surface of BaSO 4 . The optimized parameters of the coprecipitation process are 25 g L −1 BaCO 3, 700 rpm stirring rates, 1000 mg L −1 initial Bi(III) concentration at 60 °C, and the precipitation efficiency of Bi(III) reaches up to 90.4 pct. Besides, the recovery efficiency of Bi(III) reaches up to 99.25 pct under the optimized conditions of 0.5 M HCl solution at 90 °C. Importantly, with the help of a Na 2 CO 3 solution, the recycling of BaCO 3 from BaSO 4 can be perfectly realized, with a regeneration efficiency of up to 92.53 pct. This work not only clarifies the coprecipitate mechanism of Bi(III) but also provides an effective method to recover Bi from copper electrolyte.