Mechanism of Precipitate Removal of Antimony and Bismuth Impurities from Copper Electrolyte by Arsenic
This paper investigates the mechanism of removal of Sb and Bi from copper electrolyte under the function of arsenic. The precipitation reactions were carried out from a synthetic electrolyte containing 185g/L sulfuric acid and 45g/LCu2+ in the presence of As (III, V), Sb(III, V) and Bi(III) under the temperature 65°C and stirring rate of 300r/min. The structure, morphology and component of the precipitate were clarified by methods of chemical analysis, SEM, XRD, TEM, EDAX and IR spectroscopy. A kind of white precipitate has irregular shape and mainly consists of As, Sb, Bi and O elements forms in this electrolyte. The characteristic bands in the IR spectra of the precipitate are O-H, As-OH, As-O-Sb, Sb-OY (Y=As, Sb, Bi), and O-As-O. The precipitate is a mixture of microcrystalline of (Sb,As)2O3, BiSb2O7, SbAsO4 and amorphous phases by XRD and electronic diffraction. The removal rate of Sb and Bi reaches 43% and 64%, respectively from copper electrolytes by a 4g/L arsenic solution owing to these precipitate.