Isotope separation by the ''nitric acid'' method. Phase and isotope equilibrium in a system consisting of nitrogen oxides and nitric acid

This paper discusses a method proposed in 1955 by Taylor and Spindel and used today in all countries producing N 15. This exchange process method is carried out by using 10 mole/liter aqueous solutions of HNO3 at room temperature and atmospheric pressure. This paper discusses the optimization of this isotope separation process. The solution of problems connected with the process of separation of nitrogen isotopes by the nitric acid method can be carried out at a different level of knowledge of the equilibrium composition of the liquid phase. For engineering calculations related to the determination of flows in an isotope-exchange column, for the investigation and processing of experimental data according to the hydrodynamic and mass-exchange characteristics of sedimentation columns, it is sufficient to know the total amount of nitrogen due to the dissolution of nitrogen oxides in the liquid phase without regard to its chemical forms