Abstract
Due to depletion of high grade ore deposits and reinforcement of environmental regulations, many mines have resorted to use mine waste as a secondary source of metals. This minimises waste disposal and at the same time generates revenues. Vanadium slag is one of the by-products of steelmaking operations and between 25 000 and 30 000 tons are produced annually by the South African industry. This calls for alternative vanadium recovery from the slag that would be efficient and environmentally less hazardous. Bioleaching is a viable and sustainable method that will meet these requirements. This study focuses on the recovering of vanadium from the slags us! ing the microorganisms and on the reaction mechanisms. The bioleaching process was mimicked by leaching with acids under a temperature of 25oC, 2% percent solids, concentration of 150mM and an agitation of 150rev/min for 120minutes. It was found that the dissolution of vanadium from the raw slag while leaching with gluconic, citric and oxalic acid was 2.5, 3.4 and 6.1% respectively. Further studies will include choosing bacteria that produces oxalic acid, investigate the leaching process and the reaction mechanisms.