Chemical Recovery in mineral processing refers to the collection, treatment, reconcentration, and reuse of chemical reagents — particularly expensive, hazardous, or environmentally regulated substances — from process streams, spent solutions, or waste materials to reduce reagent costs, minimize environmental discharge, and support sustainable operations. Across bauxite, iron ore, gold, and diamond mining, chemical recovery is both an economic necessity and a regulatory requirement. In alumina refineries using the Bayer Process, caustic soda (NaOH) recovery is the most critical chemical recovery operation. Spent Bayer liquor, which still contains significant dissolved sodium hydroxide and sodium aluminate after aluminium hydroxide precipitation, is reconcentrated through multi-effect evaporation to restore caustic concentration and remove excess water before being returned to the digestion circuit. In gold mining operations using cyanidation, the recovery and detoxification of residual cyanide is mandated under frameworks such as the International Cyanide Management Code (ICMC). The SART (Sulfidization, Acidification, Recycling, and Thickening) process is used to recover free cyanide from copper-cyanide complexes in pregnant leach solutions and return it to the leach circuit, significantly reducing cyanide consumption and operating costs. Activated carbon used in carbon-in-pulp (CIP) or carbon-in-leach (CIL) circuits is regenerated (reactivated in kilns) after gold elution and reused multiple times. In iron ore flotation, flotation reagents in process water are partially recovered through tailings water reclaim systems. Chemical recovery programs reduce the consumption of fresh reagents, lower treatment costs for effluent discharge, and decrease the environmental footprint of mining operations.
