High temperature calcination is an important stage in the production of titanium dioxide by sul-furic acid method.Zinc salt treatment can reduce the temperature of polymorphic transition.But the in-ternal mechanism is still unclear.Using metatitanic acid and zinc sulfate as raw materials and salt treat-ment agents,the calcination is performed in a muffle furnace at 600 to 900 ℃.The effect of Zn2+on polymorphic transition and doping mechanism were discussed by XRD,HRTEM and XPS.The results show that the concentration of Zn2+and the calcination temperature significantly affect the doping mecha-nism and existence state of Zn2+in the polymorphic transition.When the concentration of Zn2+is less than 1％,Zn2+is incorporated into the TiO2 lattice in substitution mode,replacing Ti4+,increasing the cell pa-rameters and forming oxygen vacancies.And with the increase of Zn2+concentration,excessive Zn2+forms ZnTiO3 on the surface of TiO2.Substitutional doping and ZnTiO3 can reduce the phase transition tempera-ture and promote polymorphic transition from anatase to rutile through different doping mechanisms.
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