PRELIMINARY ASSESSMENT OF TRICALCIUM ALUMINATE HEXAHYDRATE FLUE GAS DESULPHURISATION

As aluminium is the world’s second most used metal and a large proportion of the energy used for its production is derived from coal-fired power stations, it follows that the alumina industry is a significant contributor to global SO_x emissions. Early attempts to address this issue quickly recognised that the combined Bayer Process residue can be used for flue gas desulphurisation (FGD). However, this waste stream can contain as little as 5.0 wt% reactive components, therefore limiting overall process efficiency and promoting the identifi cation of alternative residue streams better suited to the purpose. One such waste stream is tricalcium aluminate hexahydrate (TCA6). This paper provides data of a preliminary examination of TCA6 as a wet FGD medium with comparisons made with calcium carbonate in both sulphuric acid and simulated flue gas trials. This work supports TCA6 as an efficient and economically viable FGD medium for the alumina industry.