1.introduction. bauxite residue (br) (or red mud) is the primary byproduct of the bayer process in which bauxite ores are digested in caustics under elevated temperature (e.g., 140–250 c) to extract alumina (power et al., 2011).for every ton of alumina production, around 0.8–1.5 tons of bauxite residue is produced during the extraction process, depending on quality of the bauxite ores.