Gas phase oxidation
Use dry oxygen for gas phase oxidation at 923K-1023K:
TiCl4+O2=TiO2+2Cl2
Sulfuric acid method
First, use finely ground ilmenite and sulfuric acid (concentration ≥80%, temperature 343K-353K) to react under continuous air and stirring conditions to obtain soluble sulfate:
FeTiO3+H2SO4=TiOSO4+FeSO4+2H2O
Since this reaction is exothermic, the temperature can reach 473K when the reaction is violent.
When preparing titanium dioxide, the key step is to hydrolyze the titanium liquid:
TiOSO4+2H2O=TiO2·H2O↓+H2SO4
The concentration and acidity of the titanium solution will affect the progress of the hydrolysis reaction. The smaller the concentration, the lower the acidity and the higher the temperature, the easier the reaction will occur. In order to increase the temperature, the reaction is often carried out under pressure, which can also make the precipitated particles closer and give the product better physical properties.
