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Reduction Mechanism of Tellurium Species from Copper Electrowinning Solutions
Author(s) -
Mokmeli Mohammad,
Dreisinger David B.,
Wassink Berend,
Difley Bryce
Publication year - 2016
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.20983
Subject(s) - tellurium , chemistry , electrowinning , copper , inorganic chemistry , kinetics , reaction rate constant , electrolyte , sulfide , ion , indium , redox , electrode , organic chemistry , physics , quantum mechanics
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 Te VI reduction step with cuprous was identified and a plausible Te VI reduction mechanism was suggested. The rate‐determining step was investigated by studying the kinetics of the coupled reaction of Te VI and Te IV with cuprous. The rate law suggested for the reduction of Te IV with cuprous and the coupled kinetics equation for consecutive reduction reactions of Te IV and Te VI 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 Te VI reduction is a rate‐determining step.