METHOD FOR PRODUCING TUNGSTEN OXIDE AND METHOD FOR PRODUCING TUNGSTEN

PROBLEM TO BE SOLVED: To provide a method for producing tungsten oxide capable of reducing the release amount of a chlorine gas and reducing an environmental load.SOLUTION: The method for producing tungsten oxide comprises: a first step S1 in which tungsten carbide including cobalt is exposed inside a heating atmosphere of a process gas including a chlorine gas to generate cobalt chloride and tungsten chloride; a second step S2 in which the tungsten chloride is separated from the mixed gas including the tungsten chloride and the chlorine gas; a third step S4 in which, after the separation of the tungsten chloride, the tungsten chloride is oxidized to generate tungsten oxide and a chlorine gas; and a fourth steps S5, S6 in which the chlorine gas is separated from the mixed gas including the tungsten oxide and the chlorine gas to obtain tungsten oxide. The chlorine gas separated in the fourth steps S5, S6 is used in the first step S1.