2021-3-8 · Alumina is the feedstock to produce aluminum and is mainly extracted from Bauxite ore.[] Bauxites are composed mostly of alumina hydrate minerals and, in a lesser amount, hydrated aluminum silicate, iron, and titanium minerals.[] The common industrial way to produce alumina is the well-known Bayer process,[] in which large amounts of a residue, called bauxite residue (BR), are generated.