| 摘要 |
A process for the preparation of nitric acid of different concentrations, and preferably of a concentration below 75 percent (weak acid) and of about 98 percent (highly concentrated acid) comprising oxidizing catalytically ammonia and air under pressure to form nitrous gas, oxidizing the NO contained in the gas in a first oxidation step with subsequent chemical absorption of the oxidized NO into a nitric acid obtained in a preceding covering step, whereby a weak nitric acid is formed, and oxidizing the NO remaining in the nitrous gas in a second oxidation step completely to NO2, removing the NO2 from the gas by physical absorption into highly concentrated nitric acid, separating the NO2 from the nitric acid, liquefying the NO2 and oxidizing the liquefied NO2 with aqueous nitric acid to obtain highly concentrated nitric acid.
|
