To enable the utilization of low-grade and high-sulfur bauxite,the suspension calcination was used to remove the sulfur and the ac-tivate silica minerals,and the calcinated bauxite was subjected to a desilication process in NaOH solution under atmospheric pressure.The des-ulfurization and desilication properties and mineralogical evolution were studied by X-ray diffraction,thermogravimetry-differential thermal analysis,scanning electron microscopy,and FactSage methods.The results demonstrate that the suspension calcination method is efficient for sulfur removal: 84.21％of S was removed after calcination at 1000°C for 2 min.During the calcination process,diaspore and pyrite were trans-ferred to α-Al2O3,magnetite,and hematite.The phase transformation of pyrite follows the order FeS2 → Fe3O4 → Fe2O3,and the iron oxides and silica were converted into iron silicate.In the alkali-soluble desilication process,the optimum condition was an alkali solution concentra-tion of 110 g/L,a reaction time of 20 min,and a reaction temperature of 95°C.The corresponding desilication ratio and alumina loss ratio were 44.9％and 2.4％,respectively,and the alumina-to-silica mass ratio of the concentrate was 7.9.The Al2O3·2SiO2,SiO2,and Al2O3 formed dur-ing the calcination process could react with NaOH solution,and their activity decreased in the order of Al2O3·2SiO2,SiO2,and Al2O3.