Biological Opportunity for Beneficiation of Low-grade Bauxite

Abstract

The ore that contains <50 % of Al2O3 is called low-grade bauxite. It is suitably used for the production of the low-valued refractory materials and abrasives. The scope of its valuable use is curtailed due to the presence of different impurities like alumina-ferrite and alumina-silica. It cannot be used directly as Bayer’s process feed as its high ferrite and silica content reduce the binding energy among the alumina grains, which eventually leads to a decline in the mechanical and physical properties of different aluminum utilities. However, it would be a suitable Bayer’s process feed if the impurities can be removed in a low-cost and ecofriendly way. In this context, the conventional metal beneficiation techniques like gravity or magnetic separation, froth floatation, and reduction roasting can be applied; however, they require the huge plant set up, large amount of chemicals, and high energy input which together elevate the beneficiation cost and is of course not an eco-friendly way. Application of biomaterials in the metal beneficiation technique, especially for the removal of different impurities from the low-grade bauxite, is a suitable alternative to overcome the issues related to the process cost as well as environmental risks in the conventional beneficiation. This review article summarizes the suitability of bio-beneficiation for the low-grade bauxite.