Ammonia Oxidation: Ammonia is mixed with air and passed over a platinum-rhodium catalyst at about 800°C. This results in the formation of nitric oxide (NO) and water: 4 NH₃ + 5 O₂ → 4 NO + 6 H₂O
Nitric Oxide Oxidation: The nitric oxide produced is then cooled and reacts with more oxygen to form nitrogen dioxide (NO₂): 2 NO + O₂ → 2 NO₂
Absorption and Conversion: Finally, nitrogen dioxide is absorbed in water, producing nitric acid and more nitric oxide (which is recycled back into the process): 3 NO₂ + H₂O → 2 HNO₃ + NO
