Abstract
Addition of an acid waste to an alkaline cyanide waste was investigated for five different combinations of electroplating wastes. At the optimum final ph values of the mixtures, metals and cyanides were almost quantitatively precipitated. No evolution of hydrogen cyanide was detected. By a few additional processing steps, significant amounts of valuable metals were recovered for recycling. The waste-plus-waste step is attractive, because no reagents are required; metals are concentrated, and a relatively harmless effluent that meets most water quality standards for cyanide content is produced.
