Process for removing chloride impurities from TiO.sub.2
AssigneeE. I. Du Pont de Nemours and Company
InventorsGeorge Alan Schurr, Hans-Achim Dietmar Wildt
Life of this patent
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Abstract
A process for removing chloride impurities from TiO.sub.2 by injecting a gas selected from steam, air, nitrogen, or a mixture thereof, at a sonic or a supersonic velocity, a pressure of about 25-600 psi, and a temperature of about 140.degree.-650.degree. C., into the TiO.sub.2 to disperse it, and then separating the TiO.sub.2 from the gas and chlorides.
Claims10
A process for removing chloride impurities from TiO.sub.2 which has been produced by the vapor phase oxidation of TiCl.sub.4 at elevated temperatures, comprising:
- A. feeding the TiO.sub.2 into the treatment chamber
- B. injecting a gas selected from steam, air, and nitrogen or a mixture thereof at a sonic or a supersonic velocity into the treatment chamber directly in the TiO.sub.2 feed stream and directing the gas so that it flows crosscurrently into the TiO.sub.2 such that the gas creates a pressure difference which draws the TiO.sub.2 into the treatment chamber for 0.1 to 5 seconds, whereby the gas causes the TiO.sub.2 to disperse into discrete particles, and causes the chloride impurities to separate from the particles, wherein the initial gas pressure is about 25-600 psi and its temperature is about 140.degree.-650.degree. C., and the weight ratio of gas to TiO.sub.2 is 0.2-6.0, and
- C. separating the TiO.sub.2 from the gas and chlorides using a cyclone or a bag filter.
A process for removing chloride impurities from TiO.sub.2 which has been produced by the vapor phase oxidation of TiCl.sub.4 at elevated temperatures, comprising:
- A. feeding TiO.sub.2 vertically downward into a treatment chamber, wherein the TiO.sub.2 remains for 0.1 to 5 seconds,
- B. injecting a gas selected from steam, air, and nitrogen, or a mixture thereof, at a sonic or a supersonic velocity, into a treatment chamber through a nozzle, such that the end of the nozzle through which the gas is expelled is located in the TiO.sub.2 feed stream and the gas is injected crosscurrent to the flow of TiO.sub.2, whereby the gas causes the TiO.sub.2 to disperse into discrete particles and causes the chloride impurities to separate from the particles, wherein the initial gas pressure is about 25-600 psi and its temperature is about 140.degree.-650.degree. C., and the weight ratio of gas to TiO.sub.2 is 0.2-6.0, and
- C. separating the TiO.sub.2 from the gas and chlorides using a cyclone or a bag filter.
Dependencies are inferred from the claim text.