Catalytic composition used in purifying gaseous effluents polluted by nitrogen oxides and process for preparing the composition

摘要

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 m2/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.