Indirect carbothermal reduction of alumina for the production of aluminium has been claimed
to be better compared to the existing Hall-Heroult process in-terms of energy usage,
generation of perfluorocarbons and overall greenhouse gas emission. In the process, alumina is
reduced to an intermediate compound which is then further reduced to Al. It has been shown
from the previous thermodynamic study by the authors that high conversion of alumina can be
obtained if it is reduced to Al-chloride, Al-nitride or Al-sulphide. This paper deals with
detailed systematic thermodynamic analysis of the process through carbosulphidation route,
where alumina is first reduced to Al2S3 in the presence of reductant and sulphur source.
Various ratios of carbon to sulphur have been considered in this modelling study. In the
second stage, Aluminium is extracted from the Al2S3 through thermal decomposition,
disproportionation or electrolysis. The different thermodynamic and energy analysis of the
second stage is also discussed in this paper.