REMOVAL OF NITROGEN-OXIDES FROM SULFURIC- ACID PRODUCED BY CONTACT METHOD

Several methods of the nitrogen oxides excess removal from sulfuric ac id being produced by the contact method have been tested. Such methods as air stripping and nitrogen oxides reduction with sulfur dioxide, u rea or hydrazine have been applied. Satisfying results were achieved o nly when hydrazine was used. It was found to be the best reducing agen t acting fast and efficiently just in two minutes after adding into th e reaction medium. Final results of the purification are depended on t he primary nitrogen oxides content in acid and on the catalyst concent ration.