Electrochemical Methodology Based on Carbon Paste Electroactive Electrodes for Determination of Cyanide-Leachable Silver-Bearing Minerals in Flotation Heads

摘要

Silver metallurgy is one of the more complex of all elements because of the large number of existing silver minerals that have different cyanide leaching properties. Voltammetric measurements have been applied on carbon paste electroactive electrodes (CPEEs), in order to asses if silver-bearing minerals in flotation heads are cyanide teachable. Electrochemical methodology has been applied to seven samples, each one from different Mexican mine sites. This methodology is based in a preliminar oxidation of samples (embedded in carbon paste electrodes) immersed in aqueous medium 0.3 M NaCN, both quiescent and disturbed. Reduction of previously oxidated silver-bearing minerals were identified in voltammogram. Results shown that signal intensity is not proportional to total silver content in each sample. Therefore, observed electrochemical response is associated only to cyanide-leachable silver, which is function of both the silver-bearing minerals and the formation of galvanic interactions between the phases present in flotation heads.