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AssigneeSociete Chimique de la Grand e Paroisse
InventorsMichel Senes, Yannick Le Goff, Jean F. Gourdier, Jacques Quibel
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Gaseous effluents polluted by nitrogen oxides are purified by catalytic reduction. The catalytic compositions used contain iron and chromium associated with alumina and optionally at least a promoter selected from rare earth oxides with a content between 0.1 and 1% in relation to the active material and crude platinum metals with a content between 1 and 5 ppm in relation to the active material, the specific surface of the compositions being between 50 and 300 m.sup.2 /g and the dimensions of the pores between 40 and 50,000 A. These compositions are applicable for processes of purification of nitrogen oxides with any content.
A catalytic composition obtained by coprecipitation, used in purification of gaseous effluents polluted by nitrogen oxides, comprising as active elements, iron and chrominum in oxide form associated with alumina and, optionally, a promoter selected from the rare earth oxides, taken separately or in combination, and crude platinum metals, in which the content or rare earth oxides, when present, is between 0.1 and 1% by weight in relation to the active material;
Dependencies are inferred from the claim text.