Executive Summary : | Objective: To develop a process for the recovery of alumina from spent Bayer liquor of low alumina/caustic ratio; To test the recyclability of the spent liquor generated from the proposed process for the leaching of Bauxite; To validate the developed process through bench scale testing at processing 20 L spent Bayer liquor for improved liquor productivity and higher recovery of alumina Summary: The liquor productivity at precipitation in Bayer process, particularly in Indian alumina refineries, is limited to 55-70 g/L alumina because of which a significant amount of alumina present in spent liquor remains unrecovered and is sent through the leaching circuit. The present proposal is aimed at recovering an additional amount of alumina from spent liquor by treating it through an electrochemical process to enhance alumina to caustic ratio of the liquor followed by further processing of the liquor through seeded precipitation route which will result in improving the alumina productivity to a level of 100 g/L or more. The liquor generated after recovery of additional amount of alumina from spent liquor will be recycled for leaching of Bauxite and it is noteworthy to mention here that the liquor productivity at leaching will also be improved in contrast to the conventional practice. The developed process will be then validated through bench scale testing at processing 20 L spent Bayer liquor for improved liquor productivity and higher recovery of alumina.
CSIR-IMMT has vast experience in processing various resources such as Bauxite, fly ash, aluminium dross, etc. for the recovery of alumina and other valuable products. In addition, this group of CSIR-IMMT, Bhubaneswar has completed a number of projects sponsored by different organizations in the field of extraction of metal values from ores, concentrates including low and complex grade ores. The expertise of the division is related to leaching, electrochemical processing, purification by solvent extraction, precipitation, cementation and ion exchange, electro winning, waste water treatment, calcination, etc. |
