Study on Carbothermic Reduction of Titanium Dioxide in Vacuum

摘要

The thermodynamic calculation for carbothermic-reduction of titanium dioxide at different system pressure was carried out, the results indicated that TiO2 is reduced by carbon will be easy to produce TiC at the system pressure lower than normal pressure. Low system pressure will conduce reactions to move towards direction increasing gas and Ti will be produced at the temperature higher than 1600K when Psys =10Pa. On the basis of above calculation, carbothermic-reduction process of titanium dioxide was investigated by X-ray diffraction and self-made electric resistance determination device. The results indicated there were TiC、 TiO and Ti2O3 in reduction slag, but no any metal Ti was produced without regardless of molar ratio of TiO2 and C at the reduction temperature higher than 1673K and Psys?10Pa. Carbothermic-reduction process of titanium dioxide should pass the way of TiO2→Ti3O5→Ti2O3→TiO (TiC) with reduction temperature rising. Both diffraction peaks of TiO and those of TiC have somewhat offset maybe implies to have formed continuous solid solution of TiO-TiC. Electric resistivities of reduction slags are remarkably less than that of raw material and the reduction slag produced at lower reduction temperature have better electrical conductivity.