The experimental identification of the separation cascade of (18O) in the NO, NO2 — H2O, HNO3 system

Oxygen has three stable isotopes (¹⁶O, ¹⁷O, ¹⁸O) with a ratio of natural concentration of (99.759%, 0.037% and 0.204%). There are lot of applications in which (¹⁸O) is used, so it is necessary to produce it in industrial scale. This isotope can be separated by using various methods, one of them being the chemical exchange between nitrogen oxides (NO_x) and nitric acid (HNO₃). After a short description of the ¹⁸O separation process plant, the paper focuses on the experimental identification of the (¹⁸O) separation cascade, the first order models and the simulation of the cascade behavior.