In this study a simple and environmentally benign method for conversion of technical purity Al into high-purity alumina isdescribed. The method is based on hydrothermal oxidation of aluminium and subsequent high temperature purification ofaluminium oxide. Deep purification is achieved by high-temperature vacuum treatment of aluminium oxide at temperatureof 1600-1750 oC. Structure and chemical composition of reaction products obtained at experimental conditions at differentsteps of method are examined in presented work. It has been shown that by proposed method the Al powder of technical purity(99.8 wt.%) can be converted into high-purity alumina (99.997 wt.%). Molecular mechanics simulation of impuritiessegregation to the (0001) surface of alumina crystal has been carried out. The simulation revealed a correlation between thestrength of segregation and the efficiency of impurities removal from alumina during high-temperature vacuum treatment.

Keywords: Alumina, High purity, Hydrothermal oxidation, Boehmite, Vacuum heat treatment