Method and apparatus for producing metal oxide particles

A method for producing decahedral titanium oxide particles, the method comprising:

• combining, in a reaction tube, a preheated titanium tetrachloride-containing gas with a preheated first gas which does not contain the titanium tetrachloride at a first junction to obtain a first combined gas, and
• combining the first combined gas with a preheated second gas which does not contain the titanium tetrachloride, at a second junction which is further downstream of the first junction, to obtain a second combined gas,
• wherein at least one of the titanium tetrachloride-containing gas and the first gas contains oxygen,
• wherein the preheated titanium tetrachloride-containing gas is further heated in a first reaction zone which is a region between the first junction and the second junction by combining the first gas with the titanium tetrachloride-containing gas at the first junction while setting the preheat temperature of the first gas at a temperature higher than the preheat temperature of the titanium tetrachloride-containing gas, and the first combined gas is further heated in a region downstream of the second junction by combining the second gas with the first combined gas at the second junction while setting the preheat temperature of the second gas at a temperature higher than the temperature of the first combined gas,
• the first gas contains one or more gases selected from the group consisting of oxygen gas, nitrogen gas, and argon,
• the second gas contains one or more gases selected from the group consisting of oxygen gas, nitrogen gas, and argon, and
• the preheat temperature of the titanium tetrachloride-containing gas is equal to or higher than 500° C. and equal to or lower than 750° C., wherein an insulating material is provided in a second zone which is a region in which the first combined gas and the preheated second gas are combined to form the second combined gas, and the second combined gas flows through, wherein the insulating material is wound around the outside of the second zone so as to maintain the temperature of the gas in the second zone, and wherein no heating device is provided inside a space surrounded by the insulting material.