Chemical Grade Alumina (CGA) refers to aluminium oxide (Al₂O₃) produced to chemical purity and physical specifications suitable for applications other than aluminium smelting — the latter using smelter-grade alumina (SGA). Chemical grade alumina is manufactured using the Bayer Process from bauxite ore, but involves additional refining, washing, calcination, and classification steps to achieve the purity and particle characteristics demanded by specialty chemical, industrial, and advanced materials markets. Chemical grade alumina typically has Al₂O₃ purities of 99.5% or greater and closely controlled levels of impurities such as sodium oxide (Na₂O), silica (SiO₂), iron oxide (Fe₂O₃), and titanium dioxide (TiO₂), because even trace contaminants can compromise the performance of end-use products. Major applications of chemical grade alumina include the production of synthetic sapphire and ruby for electronics (LED substrates, watch crystals), refractories for high-temperature industrial furnaces, abrasive media (alumina grinding wheels and sandpaper), polishing compounds for semiconductors and metals, catalysts and catalyst supports in petroleum refining, flame retardants (aluminium trihydrate, ATH), and advanced ceramics for aerospace and medical applications. In bauxite mining operations, the decision to produce chemical grade versus smelter grade alumina depends on bauxite quality, refinery configuration, market demand, and price premiums available in specialty markets. Chemical grade alumina production is a higher-value pathway that leverages bauxite resources more fully and diversifies revenue streams for integrated bauxite and alumina producers.
