Method for extracting lithium isotope

Abstract

The present invention provides a method for extracting and separating lithium isotopes 7Li and 6Li. The method comprises the steps of: preparing a first organic phase: evenly mixing a hydrophobic ionic liquid and a diluent in the volume ratio of 1-15:1-10 by stirring under closed condition; then adding an extractant to form a first organic phase; preparing a first aqueous phase of an aqueous solution of lithium salt with lithium ion concentration of 0.2-5.0mol / L; mixing the first aqueous phase and the first organic phase in the volume ratio of the 1-2:1-4 to form a first extraction system; severely shocking for 5-60 min, and enriching 7Li in the aqueous phase; and then conducting reextraction to obtain 6Li enriched in the organic phase. Compared with the crown ethers and pure ionic liquid system of the prior art, the system has the advantages of low operating costs and strong industry adaptability.

Description

technical field [0001] The invention relates to the technical field of extraction and separation, especially the separation of lithium isotopes. Background technique [0002] At present, there are many separation methods for lithium isotopes at home and abroad, mainly including lithium amalgam method, extraction method, ion exchange chromatography, fractional crystallization and fractional precipitation, electromagnetic method, molten salt electrolysis, electron migration, molecular distillation and Laser separation, etc. So far, the only lithium amalgam method that can industrially produce and separate lithium isotopes in the world, and most other lithium isotope methods are only in the laboratory research stage. However, a large amount of mercury is used in the process of separating lithium isotopes by lithium amalgam method, which poses a serious threat to human beings and the environment, which greatly limits the prospect of lithium amalgam method as a source of lithium...

AI Technical Summary

Problems solved by technology

[0004] The research on the separation of lithium isotopes by liquid-liquid extraction includes: Fang Shengqiang’s “4-methylbenzo-15-crown-5’s ability to separate lithium isotopes” and “4-tert-butylbenzo- 15-crown-5 liquid-liquid extraction method for the separation of lithium isotopes is involved, but its experimental data show that the distribution coefficients are very low (far less than 1), which means that its single-stage extraction efficiency will also be very small, Not conducive to extraction and separation

[0005] Chinese patent CN1186506A discloses a method for preparing a water-soluble polymer, which involves a water-soluble polymer grafted with 15-crown-5 ether on polyvinyl alcohol, and the side-hanging 15-crown-5 structure is not Contains a benzene ring as a power supply group, and its lithium isotope separation ability is relatively weak

[0007] However, the above-mentioned system method has a low single-stage extraction rate and a large amount of organic solvents, which increases the industrialization cost of separating lithium isotopes by liquid-liquid extraction and causes certain environmental pollution problems.

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