Properties of red mud tailings produced under varying process conditions

The objective of the paper is to investigate the effect of temperature and caustic soda concentration in the bauxite digestion process on the settling behavior and the physical, chemical, and mineralogical characteristics of the derived red mud. The study was carried out on Jamaican bauxite. The results demonstrate the influence of the goethite-hematite conversion on the settling rate of red mud. This iron mineral transformation affects the specific gravity, which is one of the factors that affects the settling rate of the red muds. The iron conversion in turn is mainly affected by the temperature in the digestion step despite the variation of caustic soda concentration. The results also demonstrate that the specific surface area and the settling rate of red muds are inversely proportional and that a positive correlation exists between the amorphous and cryptocrystalline iron (Fe-d) and the settling rate of the Jamaican red muds.