The Efficient Recovery of Cobalt from Low Grade Refractory Carrollite with Bioleaching Technology

Abstract

Cobalt, having many diverse and critical uses, is an essential metal in today's society. However, the recovery of cobalt is difficult due to its associated mineral characteristics. A biohydrometallurgical process has been developed for cobalt recovery from low grade refractory carrollite. After direct oxidation for 6 days, 96.51 % Co and 26.32 % Cu were extracted from the ore using a pulp density of 10 %. The bioleaching solution contained 22.62 gL-1 ferric iron while the concentration of cobalt was only 0.83 gL-1. Therefore, a goethite deironization process was then conducted. Different conditions, such as pH value, temperature, standing time and oxidant concentration were studied in detail. The results showed that when the pH value was 4.0, oxidation temperature was 70 °C, standing time was 1 h, and oxidant concentration was 8%, then the iron removal and the loss of cobalt were 99.9 % and 0.5 %, respectively. The goethite precipitate had good filterability. The sum recovery of cobalt in the whole extraction process attained more than 95 %. The biohydrometallurgy process for the recovery of cobalt has economic and environmental advantages over the other methods.