Synthesis of high purity TiO2 powder by fluidized gas hydrolysis method is investigated.To tackle the problem of high Cl content remained in the TiO2 powder

the hydrolysis reaction conditions and subsequently calcination at air

steam and H2 are mainly investigated for dechlorination.The results show that the structure and phase transition of TiO2 are two key factors that affect the efficiency of dechlorination.With the increase of the calcination temperature

the internal structure of TiO2 is changed from porous to dense structure

and the crystalline structure is transformed from anatase to rutile.The structure and phase transition of TiO2 are beneficial to increasing the removal rate of Cl.Compared with the air calcination

the dechlorination efficiency in water vapor atmosphere is obviously improved

which is attributed to the further reaction of water vapor and the multi hydroxyl chloride in the TiO2 particles.Compared with air and steam calcination

the removal rate of Cl can be further improved up to 95% under the atmosphere of hydrogen at 800℃ for 2h

which is mainly attributed to the reduction of TiO2 structure by hydrogen reduction.