PROCESS FOR PURIFYING A SOLUTION CONTAINING METALS AND FORREMOVING SAME THERFROM AND SYSTEM FOR CARRYING OUT SUCH PROCESS PROCESSO PARA A PURIFICACAO DE UMA SOLUCAO CONTENDO METAISE PARA A EXTRACCAO DOS MESMOS E SISTEMA PARA A SUA APLICACAO

摘要

Trace metals such as copper and cadmium are removed from a solution such as a zinc sulphate electrolyte by electrolysis using a particulate bed cathode or a reticulate cathode. Electrolysis is carried out to deposit a relatively electronegative metal which is then used to cement out a less electronegative metal from solution. Usually, the more electronegative metal is a contaminant of a co-deposited less electronegative metal and in this case the cementation stage serves to purify the deposit of less-electronegative metal by dissolution of the more-electronegative metal with a simultaneous further reduction of the concentration of the less electronegative metal in solution.