Bioleaching of Cuban nickeliferous serpentinite.

摘要

Non-sulphide ore can be treated by fungi. In this case the metal extraction is due to the production of organic acids excreted into the environment. In the present work the effect of 6 organic acids in the leaching of nickel and cobalt present in serpentine from Moa mine (Cuba) was studied. The best result was obtained with 0,5 M citric acid (90% of nickel and 80% of cobalt). More over a screening from fungus strains was done according to the organic acid production by paper paper chromatography and employing different organic acids as standard. Aspergillus niger O-5 was chosen among 15 fungus strains. This strain produced 23 g/L of citric acid from sugar cane as carbon source with Y P/B= 92% in 8 days. And their chromatogram showed only one spot at level of citric acid. In the bioleaching process with 5% pulp density 59% of cobalt and 23.2% of nickel were extracted.