Worldwide, about 120 million tons of highly alkaline bauxite residue (pH ~12) are generated every year, with about 2.7 billion tons already stockpiled. Long-term storage of this production waste from aluminum production is a major issue, especially due to the hazards associated with potential soil, air, and groundwater pollution by leaking holding ponds.
Thus, remediation of bauxite residue stockpiles and options for further utilization of newly produced bauxite residue is an urgent need. Currently, no large volume applications of bauxite residue are in production besides minor used in the cement and ceramic production.
Notably, bauxite residue is a potential source for various base metal oxides (e.g. Al, Fe, Ti, Si, Ca, Na and Mg) and other rather valuable elements (e.g. rare earth elements, V, Ga, Mn, Cu).