Effects of Several Parameters on Nickel Extraction from Laterite Ore by Direct Bioelaching using Aspergillus niger and Acid Rock Drainage from Coal Mine as an Organic Substrate

摘要

Aspergillus niger is a prominent fungi that has been used for bioleaching of nickel laterite ore and commercial production of citric acid. Series of shake flask bioleaching assays have been conducted to study the effects of ore type, ore particle size distribution, solid percentage, and substrate volume percentages as well as sulphur addition on the nickel extraction from Indonesian laterite ore. Acid rock drainage (ARD) from local coal mine was used as a substrate for carbon and nutrient sources of the fungus. The results show that saprolite ore exhibits a better leaching with fungal metabolic acids than limonite. The highest nickel extraction of saprolite ore was 43%, which was obtained from the shake flask bioleaching assays with ore particle size distribution of -60+80 mesh, pulp density of 2.5%, and ARD substrate volume percentage of 10%, after 24 days of incubation. For both saprolite and limonite ore samples, coarse particle size ditribution of -60+80 mesh provides a better nickel extraction than the finer ore particle size. The addition of potato dextrose agar and fresh innoculum after 16 incubation days generated a re-increase of nickel extraction, indicating the refreshment of the active fungus. Based on the results, it was found that Aspergilus niger growth can take place with an organic substrate of liquid ARD obtained from coal mining area.