Image Number 2 for United States Patent #4064221.
The present invention relates to a process for obtaining nitric acid of a concentration higher than the azeotropic concentration by means of the absorption of nitrogen oxides in water or diluted nitric acid and the partial pressure of the nitrogen oxides before absorption is raised partly by compression of the gases that contain the nitrous gases and partly by means of a cycle of diluted nitric acid which is decomposed by the action of the NO contained in the gases, enriching them in NO.sub.2 and which subsequently reform by absorption of NO.sub.2 in water when the partial pressure of the nitrogen oxides is low.
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