Crown Ether Extraction and Separation of Lithium Isotopes

Abstract

The invention provides a process for extracting and separating lithium isotopes by crown ether. Specifically, a crown ether extraction agent is taken as an organic phase, an organic phase and a waterphase are operated continuously and adversely, the lithium isotopes are extracted and separated on extraction and separation sections C1 and C2, and mass transfer and phase inversion of lithium elements are achieved by upper and lower phase inversion sections. Buffering sections H1 and H2 are adopted, so that abundance of lithium-6 enriched products P1 and lithium-7 enriched products P2 can be adjusted conveniently, and the lithium-6 enriched products and the lithium-7 enriched products can be obtained at the same time. The process has the advantages of high separation coefficient of an extraction system, concise procedure, convenience in operation, capability of buffering and controlling flow fluctuation effectively, and high efficiency in separation and enrichment of the lithium isotopes.

Description

technical field [0001] The invention relates to isotope separation in the chemical industry, in particular to a process for extracting and separating lithium isotopes by using crown ether as an extraction agent. Background technique [0002] Natural stable isotopes of lithium include 7 Li (lithium-7) and 6 Li (lithium-6), the abundances are 92.48% and 7.52%, respectively. These two isotopes have important different uses in the field of nuclear materials after separation, enrichment and concentration. In a thorium-based molten salt reactor, 7 Li is an essential molten salt coolant due to 6 The thermal neutron absorption cross section of Li is very high, reaching 941barns, while 7 Li is only 0.033barns, so the molten salt reactor is 7 The isotopic abundance of Li is required to be >99.995%. At the same time, high-purity 7 Li is often used to adjust the pH value of the primary coolant in pressurized water reactors, and in fusion reactors 7 Li is also used as a heat ...

AI Technical Summary

Problems solved by technology

The liquid-solid extraction separation method is difficult for multi-stage countercurrent and continuous production, and the equilibration time is long, and there is no relatively mature production process at present

In principle, the liquid-liquid extraction method has the advantages of easy countercurrent cascading, low cost of extraction agent, and easy large-flow production. However, the current research reports are limited to single-stage liquid-liquid extraction, and the process of multi-stage cascade extraction has not yet been developed. There are reports

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