Abstract:
Bauxite residue is a highly alkaline waste emanating from the alumina refineries. Despite comprising of valuable elements like Fe, Al, Ti, Si, Ca, Na and certain rare earths, the utilization of bauxite residue is very limited owing to its high alkalinity and the presence of toxic elements like heavy metals and radio nuclides. Hence most of the applications employing the bauxite residue require the removal of alkaline constituents. HCl, HNO3, H2SO4 and certain organic acids have been employed to neutralize the bauxite residue. In this work, various concentrations of phosphoric acid (1M, 3M, 5M and 8M) have been used to neutralize the bauxite residue. The constituents of the calcined residue and leach liquor have been studied. In addition, the possibility of utilising the bauxite residue in solid oxide fuel cells is explored.