Characterization of Indian red mud for catalytic applications

Red mud (Bauxite waste) collected from different aluminium industries in India was characterized for its potential catalytic properties. X-ray diffraction (XRD), inductively coupled plasma analysis (ICP), BET surface area, scanning electron microscopy (SEM) and temperatureprogrammed reduction (TPR) were employed for the characterization. In addition, the effect of acid activation and calcination was investigated on the surface area of the solids. Ferric oxide (Fe 2O 3) was the main component in all samples. The main crystalline phases present were hematite, goethite, gibbsite, boehmite along with other minor forms. Surface area was found to increase after treatments (acid activation and calcination). The highest surface area obtained in activated sample was 172.54 m 2/g while in non-activated sample it was 90.06 m 2/g corresponding to a calcination temperature of 400 °C. The increase in surface area due to calcination was observed till a temperature of 400 °C after which it started declining. Based on the properties, it is proposed that without any major treatment, red mud may be a substitute for the metal oxide catalysts in several reactions.