Abstract: The method of selective catalytic purification of waste gases from nitrogen oxides consists in that the waste gas to be treated is passed, together with gaseous ammonia, through the bed of a catalyst at a temperature of 100.degree.-500.degree. C, a volumetric velocity of the waste gas of 5000 - 100000 hour.sup.-1 and a volumetric ratio of ammonia to nitrogen oxides of 0.7 - 1.5. The catalyst used in the proposed method is actually oxides of vanadium and of manganese that are taken in the weight ratio V.sub.2 O.sub.5 /Mn.sub.2 O.sub.3 of 0.1 - 30, the total quantity of the metal oxides being from 5 to 40 percent with respect to the total weight of the catalyst.

Abstract: The catalyst for selective removal of nitrogen oxides from waste gases is actually vanadium oxide and manganese oxide applied to an inert carrier. Said metal oxides are taken in the weight ratio V.sub.2 O.sub.5 /Mn.sub.2 O.sub.3 of 0.1 - 30:1, the total weight of the metal oxides being 5 - 40 per cent of the total weight of the catalyst.The proposed catalyst is prepared by dissolving ammonium metavanadate or vanadium pentoxide in an aqueous solution of oxalic acid having a concentration of 10 to 360 g/liter. A hydro-soluble salt of manganese is then dissolved in the obtained solution of ammonium oxalate-vanadate or oxalate-vanadic acid, the manganese salt being taken in such a quantity that the weight ratio of ammonium oxalate-vanadium or oxalate-vanadic acid to the manganese salt should be from 0.1 to 30:1 calculating with reference to the ratio of the metal oxides V.sub.2 O.sub.5 /Mn.sub.2 O.sub.3.