RedMud: A Secondary Resource for Rare Earth Elements

Abstract

Red mud is a solid waste of the Bayer process and is considered to be a harmful waste when it is stock piled in huge amounts. By the year of 2015, the alumina industry is estimated to produce 4 billion tons red mud worldwide at its current production rate. In India, alumina plants have 1.692 million tons of annual capacity with aluminum metal production of 0.6 million ton per annum and generate about 2 million tons of red mud every year. Disposal of red mud brings an environmental risk taking into consideration of the huge quantity. On the other hand, scattered efforts have been put worldwide for extraction of signicant amounts of REEs such as La, Ce, Y, Sc. It is difficult to directly recover REEs from red mud due to its low levels and presence of major minerals of Fe, Al, Ti. This article elicits a comprehensive review on the presence of REEs in red mud, their mineralogical characterization and its association. Also would be presented the recent first of its kind results on extraction of these rare earth elements from red mud