Removal of nickel and cadmium from battery waste by a chemical method using ferric sulphate.

The removal of nickel (Ni) and cadmium (Cd) from spent batteries was studied by the chemical method. A novel leaching system using ferric sulphate hydrate was introduced to dissolve heavy metals in batteries. Ni-Cd batteries are classified as hazardous waste because Ni and Cd are suspected carcinogens. More efficient technologies are required to recover metals from spent batteries to minimize capital outlay, environmental impact and to respond to increased demand. The results obtained demonstrate that optimal conditions, including pH, concentration of ferric sulphate, shaking speed and temperature for the metal removal, were 2.5, 60 g/L, 150 rpm and 30 degrees C, respectively. More than 88 (+/- 0.9) and 84 (+/- 2.8)% of nickel and cadmium were recovered, respectively. These results suggest that ferric ion oxidized Ni and Cd present in battery waste. This novel process provides a possibility for recycling waste Ni-Cd batteries in a large industrial scale.