Catalytic oxidation of nitric oxide in molten salt

A catalytic oxidation process is described for oxidizing nitric oxide to a higher oxide of nitrogen such as nitrogen dioxide in which a gaseous steam containing oxygen and nitric oxide is contacted with a molten alkali-metal sulfate salt containing an oxidizing agent of an oxide of vanadium to catalytically oxidize the nitric oxide in the presence of oxygen. The gaseous stream containing the higher oxide of nitrogen is then contacted with an absorbent to remove the nitrogen oxide from the gaseous stream. Preferably the absorbent is an alkali-metal carbonate that is maintained in a molten state of between 300 DEG and 500 DEG C. that reacts with the nitrogen oxide to form an alkali-metal nitrate.