Digestion Efficiency Improvement of Gibbsite-Boehmite Bauxite

Bayer digestionBayer digestion performance of gibbsiteGibbsite-boehmiteBoehmite bauxiteBauxite is studied in this paper. The chemical and mineral compositions of a gibbsiteGibbsite-boehmiteBoehmite bauxiteBauxite from Australia are analyzed and tested by XRF, XRD, and SEMScanning electron microscopy (SEM). Test results show that the bauxiteBauxite contains ≥ 50% of aluminaAlumina (gibbsiteGibbsite and boehmiteBoehmite) and 9% of silica (kaoliniteKaolinite and quartz). Its digestion efficiencyDigestion efficiency is studied in detail with various digestion conditions such as temperatures, holding timesHolding time and additivesAdditive. A medium temperatureMedium temperature digestion technology has been developed based on the study results and industrial tests in Chinese refineries: boehmiteBoehmite in the bauxiteBauxite will be totally digested in just a few minutes with bits of lime addition for a high aluminaAlumina recoveryRecovery efficiencyEfficiency and most of the unreactive silica minerals in the bauxiteBauxite are at a stable state with caustic consumptionCaustic consumption reduced by over 10%, aluminaAlumina recoveryRecovery efficiencyEfficiency increased by 2–3% compared with traditional digestion technologies. There is a great application prospect with this medium temperatureMedium temperature digestion technology for the Australian bauxiteBauxite.