CHARACTERIZATION AND RISK ASSESSMENT OF RED MUD DERIVED FROM THE SINTERING ALUMINA PROCESS

Red mud is a major waste residue of bauxite processing for alumina production using different methods. The chemical and mineralogical composition of red mud obtained from the sintering alumina process is significantly different from that of Bayer Process red mud. In order to minimize the negative effect of red mud, there are more and more investigations focusing on the utilization of red mud, such as using these wastes as raw materials in the production of building materials. However, no universal technique of full utilization of red mud has yet been developed. In this paper, red mud obtained from the sintering alumina process was characterized. Chemical and mineralogical analyses of the red mud were performed by EDX and XRD techniques, respectively. Radioactivity and toxicity characterization of the samples were also measured with gamma spectroscopy and TCLP test. It was observed that the amounts of the radioactive elements present in the red mud are within safe limits. TCLP leaching tests also showed that red mud was not hazardous and an environmentally compatible material. Therefore, if the red mud derived from sintering alumina process could be utilized as building material, it can be considered to be safe to environment and human health.