Reduction Mechanism of Tellurium Species from Copper Electrowinning Solutions

Abstract

The presence of tellurium in copper–nickel sulfide ores results in downstream contamination of leach solutions and electrolytes. Tellurium must be removed from leach solutions before electrowinning to prevent contamination of copper cathodes. Cuprous ion is industrially used as a reductant to remove tellurium ions. However, the reduction kinetics of tellurium ions with cuprous is not well known. In this study, the slow TeVI reduction step with cuprous was identified and a plausible TeVI reduction mechanism was suggested. The rate‐determining step was investigated by studying the kinetics of the coupled reaction of TeVI and TeIV with cuprous. The rate law suggested for the reduction of TeIV with cuprous and the coupled kinetics equation for consecutive reduction reactions of TeIV and TeVI were derived. It was shown that the rate constant of the coupled reaction is very close to the rate constant calculated based on the assumption that TeVI reduction is a rate‐determining step.

Extreme Environments and High-Level Bacterial Tellurite Resistance

“…In gold mines, it can be significantly concentrated (14.8 ppm) [95], and deep-sea hydrothermal vent systems can also be enriched [35]. In recent years, the use of this metalloid in industry has led to an increased environmental presence [13,67,[95][96][97]. Tellurite and tellurate are most common in the biosphere, while in the lithosphere, it is found as tellurides of gold and silver [67] and in copper ores [68,70].…”