Synthesis Process of Titanium Sulfides Suitable for the Manufacturing Process of Titanium via the Thermal Decomposition Process by Controlling Oxygen and Sulfur Partial Pressures in a Dilute Hydrogen Gas Flow

Abstract

Recently, manufacturing of metallic titanium ingots based on a thermal decomposition process using titanium disulfide TiS₂ as the intermediate product with a significantly lower decomposition temperature of approximately 4000 K was reported. However, this process involves a carbothermic reaction for preparing the intermediate product. Carbonic acid gas, a cause of global warming, was generated, and the process is inadequate from the viewpoint of environmental protection. In the present study, a reaction process without the generation of carbonic acid gas was used. Dilute hydrogen-mixed argon gas was used for the synthesis of the intermediate product. The phases of the synthesized intermediate products were investigated using X-ray diffraction and were matched to several titanium sulfide phases, such as TiS, and Ti₂S₃, which have a higher titanium ratio than the product, TiS₂, synthesized by carbothermic reaction. The thermodynamic conditions of the synthesis process, such as the partial pressures of oxygen and sulfur, were also predicted from the product phases.