高压离子交换排代法富集锂同位素(Ⅰ)——精馏型平衡塔板理论在富集同位素中的应用

ENRICHMENT OF LITHIUM ISOTOPES BY HIGH PRESSURE ION EXCHANGE DISPLACEMENT CHROMATOGRAPHY(Ⅰ) -APPLICATION OF THE EQUILIBRIUM THEORY OF THE DISTILLATION TYPE MODEL

本文根据精馏型平衡塔板理论推导出富集系数很小和有限带长时的同位素稳定谱带理论方程组,并对某些具体情况进行了分析。

Based on the equilibrium plate model of the distillation type a set of the theoretical equations have been drawn for the isotope steady band with very small enrichment factor and the band being of a limited length. That is, we used the parameters , the enrichment factor of a couple of isotopes (ε), the molar fraction of the species to be enriched in the feed (x0) and the adsorption band length expressed by the number of HETP (P) to determine the shape of the isotope steady band, the positions of the tails of the steady band and concentrations of the species to be enriched at the corresponding tails, the total enrichment of the species to be enriched in the isotope steady band,the variation of the total enrichment in the unsteady band due to the increase of the displacement distance and so forth. And some special situations were discussed.These main theoretical expressions are given by the Eqs. (2)-(10) in the paper, where P is the position of some point from x=x_(0) in the steady band;p’, the position of the front of the steady band from x=x0;x, the molar fraction of the species to be enriched at p;xe, the molar fraction of the species to be enriched at P-p’;xd, the molar fraction of the species to be enriched at p’, Eel, the total enrichment of the species to be enriched in the enriched part of the steady band;Edl , the total depletion of the species to be enriched in the dopleted part of the steady band;Ee, the total enrichment of the species to be enriched in the enriched part of the unsteady band after displacing the distance of t numbers of HETP;t, displacing distance and a, an experimentally determined constant.The expressions in this paper bear some analogy to Conrard’s in form, but P is twice that of Conrard’s because of the difference between the chromatographic motion models used.