Engelhard Corporation

Joseph H Wu

John Joseph Steger

Chung-Zong Wan

Shiang Sung

Mitchell J Willis

Zhicheng Hu

Michael G Londo

Rene S Guermonprez

Tracey A Burbank

A catalyst suitable for the treatment of automotive engine exhaust exhibiting enhanced oxygen storage capacity. The catalyst composition contains, in addition to a catalytic material such as one or more of platinum, rhodium and palladium dispersed on an activated alumina support, an oxygen storage component ('OSC') which is an intimately mixed oxide of ceria and praseodymia having a Pr:Ce atomic ratio in the range of about 2:100 to 100:100 and optionally containing one or more other rare earth metal oxides. The OSC is segregated from the catalytic material and may optionally have dispersed thereon a limited amount of a second catalytic metal component, such as platinum, rhodium and/or palladium. The intimately mixed oxide may be formed by co-precipitation by impregnation of bulk ceria particles with a praseodymium precursor, or any other method to form an intimately mixed oxide. The OSC may comprise at least about 5% by weight of the combined weight of the OSC and the catalytic component.

Catalyst composition containing an intimately mixed oxide of cerium and

A method for reducing the abrasion of a silica-containing calcined kaolin pigment by the controlled leaching of silica from the pigment, preferably by the use of a caustic solution to dissolve the silica out of the calcined kaolin. In another aspect of the invention, the brightness, opacity, or both of a calcined kaolin is increased by increasing the fineness of the kaolin feed supplied to the calciner. The combination of these methods results in the production of a calcined kaolin with low abrasion and high brightness and opacity. Another aspect of the invention concerns an improved method of filtration of dilatent materials such as the leached calcined clay.

Low abrasion calcined kaolin pigments and enhanced filtration method

The present invention relates to a zirconium, rare earth containing composition comprising zirconium, cerium, neodymium and praseodymium components and the use of this composition in a catalyst composition useful for the treatment of gases to reduce contaminants contained therein and method process to make the catalyst composition. The catalyst has the capability of substantially simultaneously catalyzing the oxidation of hydrocarbons and carbon monoxide and the reduction of nitrogen oxides.

Catalyst composition containing oxygen storage components

A catalytic material effective for the reduction of NO.sub.x and the oxidation of at least carbon monoxide includes an oxygen storage component that provides superior oxygen storage function. The oxygen storage component includes an intimately combined mixed oxides including cerium, neodymium and zirconium. Typically, the ceria constitutes more than about 30 percent by weight of the ceria plus zirconia in the intimately combined mixed oxide, e.g., from about 32 to 44 weight percent. Preferably, the intimately combined mixed oxide also includes up to about 26 percent neodymia by weight of the ceria, e.g., from 18.6 to 23.5 percent. The intimately combined mixed oxide may be a co-formed material that may be prepared by, e.g., co-precipitating compounds of zirconium and the rare earth metal and calcining the co-precipitate.

Catalyst composition containing an intimately combined cerium-zirconium

A trace amount of a polytetrafluoroethylene resin is incorporated with an abrasive pigment prior to or during the preparation of an aqueous pigment slurry or is applied to dry pigment to reduce the abrasivity of the pigment. The treated pigment can be employed in the manufacture of filled and coated paper.

Use of polytetrafluoroethylene resin particles to reduce the abrasion of

The present invention provides a simple inexpensive means to decrease the abrasivity of abrasive pigments such as calcined kaolin and titania. In accordance with this invention, a trace of a nonionic and/or anionic surfactant is incorporated with abrasion pigment prior to or during the preparation of an aqueous pigment slurry or to dry pigment.

Use of surfactants in processing abrasive pigments

The present invention provides a simple inexpensive means to decrease the abrasivity of abrasive pigments such as calcined kaolin and titania. In accordance with this invention, a trace of a nonionic surfactant of the general formula ##STR1## is incorporated with abrasive pigment prior to or during the preparation of an aqueous pigment slurry or to dry pigment.

Growing community of inventors

Somerset, NJ, United States of America

Joseph H Wu