Abstract: Preparation of titanium dioxide(TiO₂) by solid-phase digestion of ilmenite in sulfuric acid has a high acidolysis rate.Since Ethylene Diamine Tetraacetic Acid(EDTA) is a widely used complexing agent,appropriate amount of EDTA added during hydrolysis of titaniferous solution can be beneficial to the separation of titanium and iron.The mechanical and cavitation effects of ultrasound can contribute to further remove a trace amount of impurity ions.The effects of EDTA and ultrasound on TiO₂ are analyzed by the X-ray fluorescence energy disperse spectroscopy,BET specific surface area analyzer,porosity analyzer,and scanning electron microscope.DeNOXperformances of SCR catalysts taking different TiO₂ as carriers are tested.The results show that the addition of EDTA can restrain the hydrolysis of Fe³⁺,thus shorten the whole process and improve TiO₂ purity; ultrasound is helpful to remove impurity ions,and can reduce the particle sizes of TiO₂ and optimize their dispersion properties at the same time.The SCR catalyst utilizing the optimized TiO₂ as a carrier presents better catalytic activity.