A method is described for isotope enrichment by countercurrent gaseous exchange in a thermal diffusion column. The theory is derived for two cases of interest: diffusion limited and reaction‐rate limited. Solutions of the equations are presented for the over‐all separationSat the steady state as a function of the following: single stage enrichment factor &agr;; diffusion constantDor exchange rate constantk;length of columnZ;and the convective flowL,which in turn depends on pressure, temperature, column dimensions, etc. The results may be expressed in the usual formS=&agr;N. For the diffusion‐limited caseN=4&pgr;Dc¯Z/L,where c¯=moles of gas per cc. For the reaction‐rate limited case the number of theoretical plates per unit length is given by the expressionN/Z=k/v,wherevis the convective velocity.Experiments are described in which C13was concentrated by the exchange reactionC12O2+C13O&rlhar2;C13O2+C12O. The observed dependence of the over‐all separation upon the operational variables is consistent with the theory.
展开▼
