Clarification is a solid-liquid separation process used in mining and mineral processing to remove fine suspended particles from a liquid stream, producing a clear or clarified overflow liquor and a thickened underflow slurry. In bauxite refining (the Bayer Process), clarification is a critical step in which the digested slurry — containing dissolved aluminate liquor and insoluble red mud residue — is separated in large settling tanks or thickeners called clarifiers. The clarified sodium aluminate liquor is then directed to precipitation circuits for aluminium hydroxide crystallization. In gold mining, clarification is used to remove fine clays and gangue minerals from leach slurries and pregnant leach solutions (PLS) before adsorption or precipitation steps, improving reagent efficiency and product quality. In iron ore processing, clarification of wash water and process effluents removes fine iron particles and clay minerals before water is recycled or discharged. In diamond processing, clarification of water circuits removes suspended kimberlite fines, maintaining process efficiency. Clarification efficiency is influenced by particle size and density, flocculent type and dosage, liquor temperature and viscosity, and thickener design parameters such as unit area loading. Flocculants — typically polyacrylamide-based polymers — are dosed to agglomerate fine particles and accelerate settling rates.
