Characteristics of Bauxite Residue–Limestone Pellets as Feedstock for Fe and Al2O3 Recovery

Experimental research was carried out to produce pellets from bauxite residue for the further extraction of iron and alumina. Bauxite limestone with three different mixture compositions were pelletized experimentally via agglomeration followed by drying sintering at elevated temperatures. X-Ray diffraction (XRD) scanning electron microscopy (SEM) used phase microstructural analysis, respectively. Tumble, abrasion, breaking load tests applied determine strength pellets. For measurement porosity surface area, mercury porosimetry BET area methods applied. It found that 1100 °C temperature, all sintered pellet have a moderate low strength, but reverse result when 1200 temperature Moreover, 1150 high proper porosities obtained. In pellets, present in form brownmillerite (Ca2Fe1.63Al0.36O5), srebrodolskite (Ca2Fe2O5), fayalite (Fe2SiO4), while alumina mostly gehlenite (Ca2Al2SiO7) little fraction mayenite (Ca12Al14O33) phases. The identified phases are same however, variations their quantities. Porosity mechanical properties inversely related both varying composition. more CaCO3 use pelletizing, higher is However, increasing increases due clustering particles, decreases.