Osram Sylvania Inc.

Robert G Mendenhall

Joel B Christian

Raj P Singh

Tuan A Dang

Diane Seymour

Raj Pal Singh Gaur

A method for the dissolution and purification of tantalum ore and synthetic concentrates is described. The method preferably uses ammonium bifluoride as the fluoride source in place of the hydrofluoric acid used in the conventional methods. Other fluoride compounds such as NaF, KF, and CaFmay be used alone or in combination with ammonium bifluoride. The tantalum concentrate and fluoride source are combined with sulfuric acid to form a solution containing tantalum values and impurities. The tantalum values are then separated from the impurities by solvent extraction.

Tantalum concentrates dissolution and purification method

A tungsten-containing fuel cell catalyst having high electrochemical activity and its method of making are described. The tungsten-containing catalyst may be formed in situ in a fuel cell after the fuel cell is assembled. The catalyst is formed by a low temperature electrochemical activation of a tungsten-containing precursor which has been deposited on a carbon support

Tungsten-containing fuel cell catalyst and method of making same

A high-surface-area heterogenite (HCoO ) material is described for use in making submicron cobalt metal powders. The HCoO material has a surface area of at least about 90 M /g and is preferably produced by dehydrating a cobalt hydroxide precipitate at 110&deg; C.

Heterogenite material for making submicron cobalt powders

A supported tungsten carbide material is provided. The material has a unique structure as defined by its x-ray diffraction pattern and consists of extremely small crystallites on the order of about 15 to about 30 angstroms in size. The tungsten carbide material is supported on a high-surface-area support to allow for a greater number of active sites for catalysis. The support consists preferably of a high-surface-area carbon.

Supported tungsten carbide material

A phosphor paste composition for plasma display panels (PDP) is provided which comprises a phosphor dispersed in an organic paste comprising a solvent, a binder, at least one dispersant comprising stearic acid, and a plasticizer. The paste compositions are very stable and have desirable screen-printing properties. In addition, the phosphor contained in the paste retains a high percentage of its initial brightness following binder burn-out.

Phosphor paste compositions

A high-surface-area heterogenite (HCoO ) material is described for use in making submicron cobalt metal powders. The HCoO material has a surface area of at least about 90 m /g and is preferably produced by dehydrating a cobalt hydroxide precipitate at 110&deg; C.

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Waverly, NY, United States of America

Robert G Mendenhall