Red mud is composed of a mixture of solid and metallic oxides, of which iron oxide is the primary content, accounting for 60 per cent of the mass. Other dominant components include silica, unleached residual aluminium compounds, and titanium oxide. After the extraction of the aluminium component from red mud, the main components are insoluble metallic oxides, the percentage of which depends on the quality and nature of the bauxite ore and the extraction conditions.