Abstract:Sticking and glaze in retort is impeding development of magnesium production technology by indirectly heated silicothermic reduction method. At present, it is still unclear to the intrinsic mechanism of fusion and agglomeration when the sticking and glaze occurs during production. There is no reliable solution to control the fusion and agglomeration. Through a large number of thermophysical and chemical experiments, and phase detection and analysis on low-melting-point composite oxides, it was systematically revealed the mechanism of catalytic reaction causing the fusion and agglomeration, i.e., the formation of FeO or Fe2O3 and the composite oxides formed with SiO2 or CaO are the core factors causing fusion and agglomeration problem in the process of magnesium reduction by silicon thermal smelting. The softening degree and bonding degree of slag ball can be effectively controlled by controlling raw material impurities and reduction process so as to reduce content of FeO or SiO2. The scientific and reasonable control indexes of raw material impurity and the corresponding control measures were given. The results can provide basic theoretical guidance for designing the new retort of indirectly heated silicothermic reduction process.