Method of reducing NO.sub.x present in an exhaust to harmless N.sub.2
AssigneeNippon Kokan Kabushiki Kaisha
InventorsSanseki Moriguchi, Hiroshi Abe, Joichi Takenaka, Hideyuki Yoshikoshi, Osamu Komatsu
Life of this patent
Estimating the term…
Abstract
A method for reducing NO.sub.x gas contained in an exhaust gas to harmless N.sub.2 gas with NH.sub.3 gas using an iron oxide catalyst, characterized in that said iron oxide catalyst comprises a substance consisting essentially of hematite crystals (.alpha.-Fe.sub.2 O.sub.3), and the peak intensity of X-rays diffracted on the (110) plane of the lattice of said crystal has a ratio of 0.6 to about 1.0 to that of X-rays diffracted on the (104) plane of said crystal lattice.
Claims2
In the method for reducing NO.sub.x gas contained in an exhaust gas to N.sub.2 gas wherein the exhaust gas is contacted with NH.sub.3 gas and an iron oxide catalyst, the improvement wherein the catalyst consists essentially of a hematite iron ore modified from a goethite iron ore by preheating the goethite iron ore at a temperature of from 300.degree. to 900.degree. C., and having a ratio defined by the peak intensity of X-rays diffracted on the (110) plane of the lattice of the hematite crystals therein to that of X-rays diffracted on the (104) plane of said crystal lattice of from 0.6 to about 1.0.
Dependencies are inferred from the claim text.