Executive Summary : | Objective: Manganese is a vital element for energy industries as EMD (Electrolytic Manganese Dioxide) and as precursor for LIBs. More than 65% of Indian Mn deposits are low grade, which is difficult to exploit for ferromanganese industry. Currently high temperature reduction followed by leaching is practiced for treating low grade ores. In this regard, reductive acid leaching with SO2 (a toxic waste gas from several industries) having preferential fast Mn dissolution kinetics at ambient conditions while limiting the Fe will be explored for high pure energy applications such as EMD or LIB. Selective Mn leaching using novel bioleaching technique will also be explored Summary: Red mud is a potential source of valuable metal values such as alumina, iron, titania and rare earths. However, the metal recovery processes for red mud developed so far mostly emphasize on recovering a single metal component and the trial to recover two or more metallic components is recently under active way, but it has a disadvantage of consuming much cost and energy. Red mud is found to typically contain 15-18% Al2O3, 54-57% Fe2O3, 1.5-3.7% TiO2, 5-6% SiO2, 4-5% Na2O, 2- 2.5% CaO and minor amount of rare earths (La, Ce, Sc, etc.) of about 200 ppm in total. Therefore, the present project proposal has been aimed at the development of a suitable process for the recovery of alumina, iron, titania and rare earth mix-oxides from red mud so that complete utilization of red mud can be made possible. The processing of red mud will consist of the sequence of recovering iron followed by alumina, rare earth mix-oxides and titania. Initially the dried red mud will be treated for reduction roasting using solid as well as gaseous reductant followed by magnetic separation or straightway melting of the reduced mass to recover iron. Subsequent to recovery of iron, alumina, rare earth mix-oxides and titania will be extracted through hydrometallurgical processing route. Based on the extraction efficiency and ease of operational flexibility and recycling ability of the different process streams, a flowsheet will be developed for the recovery of alumina, rare earth mix-oxides, iron and titania from red mud. The developed flowsheet will be tested in bench scale for its validation, confirming the recovery values and establishment of process parameters. Based on bench scale outcome, material balance will be prepared. |
