Chemistry of inorganic compounds – Oxygen or compound thereof – Metal containing
Reexamination Certificate
2005-09-16
2010-12-21
Bos, Steven (Department: 1793)
Chemistry of inorganic compounds
Oxygen or compound thereof
Metal containing
C106S437000
Reexamination Certificate
active
07854917
ABSTRACT:
A process for manufacturing titanium dioxide by the chloride process is provided. In one embodiment, a particle size control agent comprising an ionizing agent such as potassium chloride is introduced into the reaction zone of the oxidation reactor to control the particle size of the titanium dioxide. In a first aspect, the effectiveness of the particle size control agent in controlling the particle size of the titanium dioxide is improved by adding the particle size control agent to at least one of the reactant streams at a sufficient distance upstream of the oxidization reactor to allow the ionizing agent to efficiently ionize and the particle size control agent to thoroughly admix with the stream(s) prior to entering the reaction zone. In a second aspect, the particle size control agent comprises an ionizing agent and fumed silica. In another embodiment, the amount of alumina added to the reaction zone of the oxidization reactor is increased in order to control the particle size of the titanium dioxide.
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Flynn Harry E.
Giles Jeffrey W.
Martin Robert O.
Natalie Charles A.
Bos Steven
McAfee & Taft
Tronox LLC
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