Electrolysis with Fibrous Carbon Electrodes in Recovery of Platinum Metals from Mineral and Secondary Raw Materials

Abstract

Electrolytic recovery of platinum metals onto electrodes of fibrous carbon materials from solutions formed by processing of copper–nickel ores, gold- and silver-containing concentrates (gold and silver refining), platinum–rhenium catalysts, and simulated solutions from spent nuclear fuel reprocessing was studied. Combined flowsheets including electrolysis with fibrous carbon electrodes, anodic labilization of platinum metal compounds, extraction, and ion exchange were used. Platinum metals were recovered to low residual concentrations from sulfuric acid, hydrochloric acid, hydrochloric acid + thiourea, ammonia–ammonium, nitric–nitrous acid, and nitric acid solutions. The following processes were used: electrolysis at constant and varied current density, deposition–anodic dissolution, and deposition–dissolution in the short-circuited electrochemical system fibrous carbon material–metal alloy–electrolyte solution. Some processes were successfully trialed on the semicommercial and commercial scales. Trials were performed using semicommercial electrolyzers with fibrous carbon electrodes, developed in cooperation with the special designing bureau of mining and dressing equipment.