Electrochemical characterization of the effects of impurities and organic additives in lead electrowinning from fluoborate electrolyte

The effects of glue and calcium lignin sulfonate additives, and chloride an d antimony impurities on the lead electrowinning process, using a fluoborat e electrolyte, were studied. Short-term deposition tests, voltammetry, elec trochemical impedance spectroscopy (EIS) and SEM techniques were used for t he evaluation. The interactions among additives and impurities were also ev aluated. The presence of antimony or chloride ion in the range of 50 to 200 mg/L was shown to cause a more dendritic and powdery lead deposit. Additio ns of glue and calcium lignin sulfonate at selected concentrations helped t o level the deposit and counteracted the detrimental effects of chloride an d antimony. The voltammetry and EIS characteristics obtained with additions of glue and calcium lignin sulfonate to the electrolyte indicated the role s of these components in modifying the lead deposition mechanisms and the d eposit morphology. (C) 2001 Elsevier Science BN. All rights reserved.