Crown Ether Extraction and Separation of Lithium Isotopes

A lithium isotope and extraction technology, applied in the chemical industry, can solve the problems of difficult multi-stage countercurrent and continuous production, no relatively mature production process, and the multi-stage cascade extraction process has not yet been reported.

Active Publication Date: 2020-03-06
SHANGHAI INST OF ORGANIC CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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

Method used

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  • Crown Ether Extraction and Separation of Lithium Isotopes
  • Crown Ether Extraction and Separation of Lithium Isotopes
  • Crown Ether Extraction and Separation of Lithium Isotopes

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0080] Connect the pipelines according to the process diagram, and a total of 20 centrifugal extractors are used in the extraction and separation C1 section and the extraction and separation C2 section. The buffer H1 section contains a liquid storage tank with a volume of 0.025m 3 ;The buffer H2 section contains a liquid storage tank with a volume of 0.002m 3 .

[0081] Organic phase: the extractant is dicyclohexyl 18-crown-6, the diluent is dichlorobenzene, and the separation coefficient of the single-stage extraction of the organic phase is 1.031.

[0082] Lithium-containing feed solution (F): LiI aqueous solution, 2.5mol / L, wherein the abundance of lithium-6 is 7.48%, and the abundance of lithium-7 is 92.52%.

[0083] Through the feeding pump, the organic phase, aqueous phase and feed liquid are continuously added, and the entire extraction process is run. After 65 hours, the system reaches equilibrium, and the enriched product is continuously separated and obtained:

[...

Embodiment 2

[0086] The technical process and the feed liquid all adopt the parameters in Example 1, only changing the volume of the storage tank in the buffer H1 section to 0.050m 3 . Enrichment products that are different from the abundance values ​​in Example 1 can be continuously obtained:

[0087] The lithium-7 abundance value of the lithium-7 enriched product (P1) is 93.27%, and the extraction and separation C1 stage efficiency is 95%; the lithium-6 abundance value of the lithium-6 enriched product (P2) is 10.20% , The extraction and separation C1 stage efficiency is 95%.

Embodiment 3

[0089] Connect the pipelines according to the process diagram, use 25 centrifugal extractors for the extraction and separation C1 section, and 55 centrifugal extractors for the extraction and separation C2 section. The buffer H1 section and the buffer H2 section contain liquid storage tanks and temperature controllers.

[0090] Organic phase: the extractant is 4-tert-butylbenzo-15-crown-5, the diluent is kerosene, and the separation coefficient of the single-stage extraction of the organic phase is 1.032.

[0091] Lithium-containing feed solution (F): LiClO 4 Aqueous solution, 3.0mol / L, in which the abundance of lithium-6 is 7.49%, and the abundance of lithium-7 is 92.51%.

[0092] Through the feeding pump, the organic phase, aqueous phase and feed liquid are continuously added to run the entire extraction process. After the system reaches equilibrium, continuous separation and enrichment products are obtained:

[0093]The lithium-7 abundance value of the lithium-7 enriched ...

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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 ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D59/24
CPCB01D59/24
Inventor 胡金波张伟张丽君
Owner SHANGHAI INST OF ORGANIC CHEM CHINESE ACAD OF SCI
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