Removing nitrous gases from waste - esp. from nitric acid prodn., by oxidn., and absorption in water and in magnesia suspension

摘要

Nitrous gases are removed from waste gases, esp. from nitric acid prodn., by (a) prolonged oxidn., (b) absorption of part of the oxidised gases in the large amt. of water needed for nitric acid prodn., with recycling of these absorbed gases into the process, and (c) absorption of a large part of the remaining gases in an aq. suspension of MgO in a wash-tower. The conc. soln. of Mg nitrite-Mg nitrate obtd. can be sold as a fertiliser. The remaining gas can be vented to the atmos. and contamination is avoided. Blocking of the plant, as occurs when Ca(OH)2 is used, is avoided.