Alumina refining (Bayer technology):

The bauxite is blended, crushed and mixed with the recycled caustic soda in the form of solution in the ball mills. The ground slurry is pumped to desilication units and then to digesters. The slurry is heated by steam to facilitate the dissolution of alumina from the bauxite. The supernatant liquor is filtered and passed through plate heat exchangers where it is cooled and the alumina hydrate precipitated. The alumina hydrate is fed to the kiln where it is calcined at a temperature of 1,200 degrees Celsius. The diluted slurry is pumped to settlers, where starch is added to accelerate the settling of the red-mud. The underflow mud is subsequently washed counter-currently in four washers to recover the caustic soda. The last washer mud is then filtered prior to being pumped into the red-mud ponds. On the refinery site there are facilities for producing process steam and compressed air. Electricity for the refining process is supplied by a captive power plant.

Aluminium smelting (Vertical Stud Soderberg technology):

Calcined alumina from the refinery is fed from the storage silos into the electrolytic cells at the smelter. Cryolite is mixed with the alumina and this solution is maintained at a high temperature to carry on the process of electrolytic reduction. This produces aluminium metal over a period of 48 hours. Electricity for the smelter process is supplied by a captive power plant.

GAMI Technology

BALCO's newer 250,000 tpa aluminum smelter uses pre-baked technology from the Guiyang Aluminum Ì Magnesium Design & Research Institute, or GAMI, of China. In this pre-baked process, alumina is converted into primary aluminum through a smelting process using electrolytic reduction. The reduction process takes place in a reduction cell, referred to as the pot, where alumina is reduced to molten aluminum. From the pot-line, the molten aluminum is sent to the fabrication facility.