Leaching of copper converter slag withAspergillus niger culture filtrate

Leaching of copper converter slag of M/s Hindustan Copper Ltd, Ghatshila (Bihar, India) was carried out usingAspergillus niger culture filtrate. The effects of the duration of leaching, temperature, pulp density and the addition of hydrochloric acid were studied.A. niger culture filtrate solubilized metals from the converter slag at levels of 18.70% copper, 7.40% nickel and 4.00% cobalt. Addition of hydrochloric acid was found to improve copper, nickel and cobalt solubilization to 46.52, 27.90 and 37.96%, respectively. HPLC analysis of the fungal culture filtrate revealed the presence of succinic and citric acids. Therefore, leaching of the slag was also carried out with matching concentrations of these organic acids individually as well as with both mixed together. Results are discussed.