An extraction system for extracting lithium isotopes

Abstract

The invention provides an extraction system for extracting lithium isotope. The system comprises an extracting agent, a hydrophobic ionic liquid and a diluent. The hydrophobic ionic liquid and the diluent are in the volume ratio of 1-15:1-10; the extracting agent has concentration in an extraction organic phase of 0.05-2.5mol / L; the extracting agent is at least one of benzo-15-crown-5 and a derivative thereof, or benzo-14-crown-4 and a derivative thereof. 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...

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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" published in "Nuclear Chemistry and Radiation Chemistry" 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 CN 1186506A discloses a preparation method of 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 Does not contain a benzene ring as a donor 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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