UTILIZATION OF MICROBIAL INTERACTIONS FOR MOBILIZATION OF VANADIUM FROM STEEL SLAG

摘要

Production of high grade steel generates vast amounts of slag. Some, e.g. LD-slag, are potential sources of valuable elements such as vanadium. To recover vanadium with a minimum of added chemicals and energy, bioleaching of LD-slag with naturally occurring heterotrophic microorganisms in combination with a cheap and readily available carbon source (wood chips) are tested. Reactors holding 1 m~3 each were loaded with LD-slag and wood chips and kept at field capacity during three years. By mixing LD-slag and wood chips the initial vanadium content in leachates was approximately 5 mg L~(-1). With wood chips covering the LD-slag the leachates contained less than 0.5 mg L~(-1). However, after one year both reactors produced leachates containing 4-5 mg L~(-1) vanadium. With prolonged leaching and extended sampling intervals the content of vanadium in the leachates decreased to some 1-2 mg L~(-1). This indicates that a reducing environment is necessary for a high mobilization of vanadium.