Electrochemical Recovery of Cadmium from Simulated Waste Nickel-Cadmium Battery Solutions

摘要

The selective recovery of Cd from simulated spent nickel-cadmium battery solutions was achieved using a Cd working electrode in a laboratory cell with a three-electrode arrangement in hydrochloric, nitric, and sulfuric acids. The latter was selected for further study of the recovery step. Nitrate media were found to be unsuitable for Cd recovery since nitrates are reduced at the required deposition potentials. Cd(II) deposition on Cd electrodes is favored in sulfate or chloride media since it occurs at a potential some 200 mV less negative than that of Ni(II). A good percent Cd recovery (>90%) with high selectivity (approximately 0% Ni) and a reasonably high current efficiency (>80%) can be achieved under appropriate conditions. The irreversible nature of Ni(II) reduction provides the necessary framework to achieve such a selective separation.