The mineralogy changes in red mud after reaction with S02

Abstract

An incentive to investigate the mineralogy of red mud after the reaction with SO2 was carried out in this study to identify whether that the chemical properties of red mud are suitable for use as a sorbent in the flue gas desulphurisa-tion process. The main purpose of this study is to evaluate how SO2 gas affects the minerals in solid and liquid phase of the red mud at different contact time. Red mud samples from Worsley Alumina Pty. Ltd(WAPL), Western Australia were used in this study and were examined using XRD, XRF and ICP analysis to identify the changes in the red mud composition. From the XRD analysis, WAPL red mud prior to reaction with S02 implied that it was mainly composed of goethite, hematite, aluminium silicate, potassium magnesium hydrogen aluminium silicate hydrate, and sodium titanium silicate. However, after the reaction between red mud and SO* it is observed that goethite is the dominant mineral while other minerals were fluctuates over time. This scenario is different for the XRF analysis whereby main constituent of the treated red mud is hematite. This is followed by alumina, quartz, and anatase while the rest of elements present comprise < 1.0%. However, the ICP analysis of treated red mud at different contact time implies that there are six main elements (Na, Al, S, K, Ca, P) which are most highly concentrated in the liquid phase of red mud, while other elements (Co, Cu, Fe, Go, Mg, Mn, Ti, Zn) disappeared into the solid phase, explaining why only trace amounts of them were detected in the liquor.