High temperature smelting reduction of bauxite residue and a CaCO3-rich bauxite for aluminate slag production and pig iron recovery

An alternative way of producing alumina, called the Pedersen process, is suggested
in the current study. It is a pyro- and hydrometallurgical process, the main
advantage being the valorization of the bauxite residue. In the present research,
the smelting reduction of bauxite residue and a CaCO3-rich bauxite beneficiation
by-product is studied to produce a calcium-aluminate slag and pig iron. Based on
the results, increasing the CaO/Al2O3 ratio in the produced slags, can lead to the
formation of phases that are considered leachable for alumina recovery, as
12CaO.7Al2O3, CaO.Al2O3, 3CaO.Al2O3. An optimum wt%CaO/wt%Al2O3 ratio of 1.5
is defined for the formation of a slag with more leachable phases. Proper slag and
metal separation occurred, indicating the feasibility of producing two valuable byproducts
applying the Pedersen process.