Stephen D Taylor

US Patent:

6811721, Nov 2, 2004

Filed:

May 30, 2003

Appl. No.:

10/448692

Inventors:

Stephen W. Taylor - Chadds Ford PA

Assignee:

E. I. du Pont de Nemours and Company - Wilmington DE

International Classification:

C09K 322

US Classification:

252 881, 252 882

Abstract:

The present invention provides a composition and a method for reducing the production of persistent bio-accumulative and toxic pollutants in solid carbonaceous reduction reactions in carbochlorination processes.

US Patent:

20080105165, May 8, 2008

Filed:

Jun 8, 2007

Appl. No.:

11/811078

Inventors:

Russell Bertrum Diemer - Wilmington DE, US
Alan Roger Eaton - Newark DE, US
Narayanan Sankara Subramanian - Hockessin DE, US
Stephen William Taylor - Chadds Ford PA, US

International Classification:

C09C 1/36

US Classification:

106437, 422158

Abstract:

This disclosure relates to process for producing titanium dioxide (TiO) pigments, comprising the following steps: a) oxidizing a mixture of titanium tetrahalide and a rutile forming agent, such as aluminum halide, present in the vapor phase and in the presence of a nucleant to form a gaseous suspension comprising titanium dioxide particles; b) passing the gaseous suspension to a cooling conduit; c) introducing scouring material into the cooling conduit; wherein the particles of the scouring material have a diameter in the range of about 0.25 mm to about 12.7 mm; d) separating the vapor phase to form a powder comprising the titanium dioxide particles and the scouring material; and e) simultaneously subjecting the powder to substantially uniform heating at a temperature of about 300 C. to about 600 C. and reducing the size of the titanium dioxide particles and the particles of the scouring material in the powder to a mean particle size of about 50 nm to about 1000 nm, whereby the titanium dioxide pigment has a chloride content of less than about 500 ppm. The so treated powder may have a residual free chlorine content of less than about 1 ppm.