Investigation of the usability of bioleaching method in nickel recovery from lateritic nickel ores

In this study, the applicability of bioleaching method for nickel recovery from laterite nickel ore was investigated. Acidithiobacillus ferrooxidans, a natural isolate coded 3A isolated from activated sludge, was used in the bioleaching of limonite and nontronite type ores taken from Gördes lateritic nickel deposit. In order to determine the optimum bioleaching conditions, the effects of pulp density, particle size, initial pH and temperature on bioleaching efficiency were investigated. Maximum nickel dissolution (75%) in the nontronite ore sample was achieved at 300C temperature, 1,5% pulp density, initial pH 2,5 and -0,038 mm particle size. Maximum nickel dissolution (62%) in limonite ore was achieved at 250C temperature, 1,5% pulp density, initial pH 2,0 and -0,038 mm particle size. Acidithiobacillus ferrooxidans showed optimum activity at 250C The dissolved nickel was precipitated by hydroxide precipitation method (>98%). Dissolved nickel hydroxide was precipitated by precipitation method (>98%). The nickel ratio in the precipitate obtained from nontronite type ore was determined as 82% and the nickel ratio in the precipitate obtained from limonite type ore was determined as 69%. According to the data obtained from this study; it was concluded that nickel dissolution can be done from Gördes laterite nickel ore by indirect bioleaching of chemolithotrophic bacteria. Due to the potential environmental pollution that may occur with chemical leaching and the negativities such as high cost; the use of biotechnological methods in the industry is an important advantage. Keywords: Acidithiobacillus ferrooxidans, Bioleach, Laterite, Nickel