Dry Beneficiation Studies of Low-Grade Chromite Ore Using Magnetic Separation

In general, chromite ore is beneficiated using gravity separation in multi-stage by using different unit operations along with classifiers. Traditional beneficiation flowsheets comprise key unit operations such as wet gravity separation, magnetic separation, and flotation to enrich low-grade chromite ore. However, the process is wet based, requiring substantial water, making it less environmentally sustainable than processing low-grade chromite ore. So, exploring an alternative flowsheet with the dry option to treat such low-grade ores is possible. Dry beneficiation techniques offer a promising alternative by eliminating the need for water and reducing energy consumption; hence, dry beneficiation has gained significant attention in recent years. The effectiveness of dry beneficiation is influenced by a range of factors like mineralogical composition, particle size distribution and liberation characteristics. In the present investigation, detailed characterization studies of low-grade ore were conducted to understand the mineral assemblage and liberation properties. The low-grade chromite ore was analysed for 26.11% Cr₂O₃ with 20.5% SiO₂, and mineralogical studies indicated the presence of lizardite and chrysotile in association with chromite. Dry beneficiation was employed to upgrade the low-grade chromite ore and dry high-intensity magnetic separators using rare earth-roll magnetic separators. It was possible to upgrade the low-grade ore to >34% Cr₂O₃ and SiO₂ <16%, which was acceptable to the ferrochrome production but otherwise deemed unusable. The results obtained are discussed along with the challenges observed and the scope of further research in enhancing chromite recovery.