Fine particulate titanium dioxide, and production process and use thereof

1. A process for producing a fine particulate titanium dioxide, comprising:

a first step of high-temperature oxidizing a titanium tetrachloride-containing gas with use of an oxidative gas to produce a titanium dioxide powder,

a second step of contacting water vapor with the titanium dioxide powder while rolling the powder in a heating furnace, thereby effecting dechlorination and at the same time, increasing the adsorbed water,

a third step of packaging the powder produced in the second step in a resin bag, comprising spraying water droplets having a liquid droplet diameter of 5 to 500 μm onto the powder in the bag, and then closing the bag, and

a fourth step of storing the powder in the bag.

2. The process for producing a fine particulate titanium dioxide according to claim 1 , wherein the oxidative gas is water vapor.

3. The process for producing a fine particulate titanium dioxide according to claim 2 , wherein the amount of water vapor contacted is from 2 to 30 mol per mol of the titanium tetrachloride gas.

4. The process for producing a fine particulate titanium dioxide according to claim 1 , wherein the titanium tetrachloride-containing gas and the oxidative gas supplied to the reaction tube each is preheated at a temperature of 600° C. to less than 1,100° C.

5. The process for producing a fine particulate titanium dioxide according to claim 1 , wherein in the second step, the water vapor and the powder are counter-currently contacted by introducing the water vapor into the heating furnace at a ratio of 1 to 60 mass % based on the titanium dioxide powder.

6. The process for producing a fine particulate titanium dioxide according to claim 1 , wherein in the second step, the water vapor and the powder are counter-currently contacted by introducing the water vapor into the heating furnace at a ratio of 1 to 50 mass % based on the titanium dioxide powder.

7. The process for producing a fine particulate titanium dioxide according to claim 1 , wherein in the second step, the titanium dioxide is heated at 150 to 500° C.

8. The process for producing a fine particulate titanium dioxide according to claim 1 , wherein in the second step, the residence time of the powder in the heating furnace is from 0.5 hours to less than 3 hours.

9. A process for producing a fine particulate titanium dioxide, comprising charging a fine particulate titanium dioxide powder in a resin bag, spraying water droplets having a liquid droplet diameter of 5 to 500 μm onto the powder in the bag, and closing the bag for storing the powder in the bag.