RECOVERY OF METAL VALUES FROM RED MUD

In processing bauxite for production of alumina by the conventional Bayer process, huge quantities of so called red mud are generated which are disposed of as a waste product. The red mud is normally contains caustic soda and therefore poses pollution hazardous and requires storage in specially made large size ponds. This waste material at present does not find any use, hence, in addition to the pollution hazard, considerable expenditure and wastage of land is involved in disposal of this waste material. Therefore, in view of the increasing problem of waste disposal, it is desirable to recover the oxides of iron, titanium and aluminum from red mud. The process applies to the recovery of alumina, titania and ferric oxide from red mud which comprises the following steps (i) Roasting of red mud in presence of alkali (ii) Extracting the salts produced in step (i), (iii) Precipitation of hydroxide salt and (iv) Converting the hydroxide salt into oxides. Balco's red mud contains 45-47% Fe2O3, 18-20% TiO2 and 16-25% of undigested alumina. Many methods have been tried by others to recover the metal values and it is proposed in the laboratory on bench scale. The present papers provide an alternative and more environmentally acceptable process for the recovery of iron, titanium and aluminum from Balco's red mud.