LAUSR

Abstract Although electrochemical characterization has been used to elucidate the species formed during hydrometallurgical processes, it has not been commonly applied to the cyanidation of precious metal tellurides. In this study, voltammetric characterization of the silver telluride (Ag2Te) reaction system in alkaline cyanide solutions (pH 10.9 and 1250 mg/L CN−) was carried out making use of carbon paste electrodes. For this purpose, the electrochemical reactions system of elemental silver and elemental tellurium were first studied by cyclic voltammetry in two aqueous media (i.e., aqueous solution at pH 10.9, and 1250 mg/L CN− at pH 10.9) and, by comparing the cyclic voltammograms obtained with those for Ag2Te, the electrochemical reaction system was elucidated. The results obtained showed that the anodic oxidation of Ag2Te in alkaline cyanide solutions occurred by at least two consecutive steps according to: Step 1 (fast reaction): Ag2Te + 4CN− ↔ Te + 2Ag(CN)2− + 2e−. Step 2 (slow reaction): Te + 3H2O ↔ TeO32− + 6H+ + 4e− while the cathodic reduction of Ag2Te in alkaline cyanide solutions occurred according to: Ag 2 Te + 2 e − ↔ 2 Ag + Te 2 −