Beneficiation and Extraction of Strategic Scandium (Sc) from Aluminium Industry Waste Residue

Bauxite residue is generated during Bayer’s process, which produces alumina from bauxite. In accordance with available land space, the residue is typically disposed of at an industrial site in man-made mud ponds. REEs are present in significant amounts in bauxite residue, and India generates a sizable amount of it (>10 MT). As a result, they contain enormous amounts of REEs that can serve as a valuable secondary source for these elements. REEs are rarely found in concentrated deposits, so their primary production is constrained. Scandium is the most strategically important and national priority among the various REEs. There are no known scandium deposits with concentrations higher than 100 mg/kg. As a result, materials like Bauxite residue with a scandium content of 50 mg/kg or higher can be regarded as ore. A list of 12 essential minerals that could be crucial for the fulfillment of the “Make in India” program and the sustainable development of the Indian economy was released by the Council on Energy, Environment, and Water. With more than 90% of the global market’s supply of rare earth oxide (REO), China is the world's top supplier. Less than 2% of the world's REO is produced in India. The development of different processing techniques for the extraction of REEs from this residue has been identified as key to this issue. The developed process will aid in the handling of such a significant amount of waste, thereby minimizing statutory and regulatory scrutiny over waste treatment. Physical beneficiation and process know-how for the successful separation and recovery of REEs from bauxite residue are presented in this study.