Tungsten Dissolution from Hutti Goldmine Overburden by Aspergillus niger

Abstract

Tungsten is an important alloying component for the production of different materials. Its efficient extraction from different sustainable resources is necessary to meet the growing demand in the future. In this context, an attempt has been made to recover it from a goldmine overburden sample using the fungal bioleaching technique. The sample contains 0.023% of WO3 in the form of scheelite. The prospect of bioleaching for tungsten recovery from the sample was evaluated by varying pulp density from 1 to 7% (w/v). The leaching rate of tungsten decreased with the increase of pulp density. The maximum tungsten recovery of 86.8% (w/w) could be achieved at the condition of pulp density, 1% (w/v); pH, 6.8; temperature, 32 degrees C; speed, 120 rpm; contact time, 10 days. Growth of the fungal strain Aspergillus niger in terms of organic acids production was evaluated during the bioleaching experiment and found to be maximum at the pulp density of 1% (w/v). The leaching kinetics of tungsten followed the chemical control model.