The role of arsenic in the homogeneous precipitation of As, Sb and Bi impurities in copper electrolyte

• Published in: Hydrometallurgy Vol. 108; no. 3; pp. 199 - 204
• Main Authors: Wang, Xue-Wen, Chen, Qi-Yuan, Yin, Zhou-Lan, Wang, Ming-Yu, Tang, Fang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.2011; Elsevier
• Subjects: Applied sciences; Arsenato antimonate; Arsenato antimonic acid; Copper electrorefining; Electrolyte purification; Exact sciences and technology; Metals. Metallurgy; Production of metals; Electrolyte purification; Copper electrorefining; Arsenato antimonic acid; Arsenato antimonate; Precipitation; Purification; Impurity; Electrorefining; Microstructure; Hydrometallurgy
• ISSN: 0304-386X; 1879-1158
• DOI: 10.1016/j.hydromet.2011.04.007

The role of arsenic in the homogeneous precipitation of impurities arsenic, antimony and bismuth in copper electrolyte was studied. Experiments found that though the formation of arsenato antimonates is one of the control-steps in the homogeneous precipitation and antimony is absolutely necessarily for arsenato antimonates formation, arsenic played an important role for the homogeneous precipitation as well. Arsenic (V) is not only a reactant of arsenato antimonates formation but also an oxidant of Sb(III) oxidation. Arsenic (V) can oxidize antimony from Sb(III) to Sb(V) in copper electrolyte. If the concentration of arsenic (V) is over 6 g/L and the mole ratio of As(III)/As(V) is less than 0.09, the oxidation can be taken place at room temperature, and the equilibrium value of the φ As(V)/As(III) is about 0.606 in the electrolyte. Under these conditions, the precipitation rate of antimony from the electrolyte can be reached over 97%. Arsenic (III) can promote arsenato antimonates formation and depress floating slimes formation simultaneously. The higher the arsenic (III) concentration is, the easier the formation of arsenato antimonates will be. If arsenic (III) is lack, the copper electrolyte is prone to be over oxidized, which will result in the formation of floating slimes. Floating slimes and arsenato antimonates have a similar chemical composition. To distinguish arsenato antimonates from floating slimes, the most effective way was thermal decomposition. ► Arsenic plays an important role in the homogeneous precipitation of impurities arsenic, antimony and bismuth in copper electrolyte. ► Arsenic (V ) is not only a reactant of arsenato antimonates formation but also an oxidant of Sb(III) oxidation. ► Arsenic (V) can oxidize antimony from Sb(III) to Sb(V) in copper electrolyte. ► Arsenic (III) can promote arsenato antimonates formation and depress the floating slimes formation simultaneously.