Electrochemical Leaching of Cobalt from Cobaltite: Box-Behnken Design and Optimization with Response Surface Methodology

Abstract

Cobalt, a critical metal, is anticipated to increase in market demand in the next couple of decades, particularly as a battery material used in electric vehicle application. To boost the domestic production of cobalt in the United States, an electrochemical process has been developed to recover cobalt from a cobaltite-rich concentrate and produce cobalt- and arsenic-rich leachate. The leaching efficiency of cobalt was optimized with a response surface methodology by modifying the electrochemical parameters. A series of experiments based on the Box-Behnken design of experiments were carried out using ferric iron as an electrochemically generated oxidant to leach metals from the concentrate. Operating parameters, such as electrochemical cell current, iron/arsenic molar ratio, and anolyte acidity, were optimized for maximum cobalt recovery. A predicted 73% cobalt extraction efficiency can be achieved with the electrochemically assisted leaching method within 24 h. Compared to other leaching methods, such as bioleaching, electrochemically assisted leaching shows a promising alternative for extracting metals from mining concentrates, showing higher efficiency in less time and under mild conditions.