Removal of harmful substances from gases in uranium processing

Gases from hydrometallurgical uranium processing are treated by absorption through direct contact of the steam-gas mixture with the ore sludge. 40 to 60% of nitrogen oxides are captured. Nitrogen oxide removal from gas proceeds in three stages, viz., condensation and partial absorption, oxidation absorption, chemical or oxidation-regeneration absorption as the final hygiene gas treatment prior to its release into the atmosphere. The final product of absorption is nitric acid and nitrate solutions. Ammonia is converted to ammonium carbonate and ammonium hydrocarbonate using chemical reactions with water and carbon dioxide. Emphasis is laid on regeneration and re-use of chemicals and on the recycling of wastes that do not represent an environmental risk. (M.D.)