Method for separating and enriching < 7 > Li isotope through extraction-electromigration coupling

Abstract

The invention discloses a method for separating and enriching < 7 > Li isotope through extraction-electromigration coupling. The method comprises the following steps: uniformly mixing an ionic liquid, a diluent and a crown ether compound to form an extraction organic phase; uniformly mixing the extracted organic phase with a lithium salt solution, extracting, and collecting a lithium-loaded organic phase; the anode, the cathode, the anolyte, the catholyte and the isolating membrane jointly form an electromigration system, wherein the anolyte is the obtained lithium-loaded organic phase, and the isolating membrane is arranged between the anolyte and the catholyte; and finally, electrifying the electromigration system to obtain the cathode solution rich in < 7 > Li. According to the method, under the action of an electric field, the lithium isotope separation effect continuously exists, the enrichment limitation of the front end and the tail end of an ion migration flow does not exist, the isolation membrane is not subjected to saturation capacity limitation, meanwhile, all solution phases can be recycled, and the process is clean and environment-friendly; in addition, the process has no special requirements on temperature, humidity, air and the like, and sealing is not needed.

Description

technical field

[0001] The invention belongs to the technical field of lithium isotope separation and enrichment, and specifically relates to an extraction-electromigration coupled separation and enrichment 7 Li isotope method. Background technique

[0002] High-abundance lithium isotopes play an important role in national economy and national defense security. More than 99.9% abundance 7 LiOH is an acidity regulator for pressurized water reactors, 7 LiBeF is the neutron moderator of the new molten salt reactor. 30%~90% abundance 6 Li is an indispensable raw material for fusion reactors and hydrogen bombs, and is also used in various neutron detectors. With the maturity of molten salt reactor and fusion reactor technology, domestic and foreign markets will demand 7 Li and 6 Li's demand will increase day by day. and 7 Li and 6 The natural abundances of Li are 92.5% and 7.5%, respectively, which cannot be directly applied to the above fields, and must be separated by...

Examples

preparation example Construction

[0051] Further, the preparation method of the lithium-loaded organic phase also includes: obtaining by directly dissolving lithium salt in the extracted organic phase or driving lithium ions into the extracted organic phase by an electric field.

[0052] Further, the concentration of lithium ions in the anolyte is above 0.05mol / L.

[0053] Further, when the concentration of lithium ions in the anolyte is lower than 0.05mol / L, a new anolyte can be replaced.

[0054] Furthermore, the anolyte with a lithium ion concentration lower than 0.05 mol / L can be reused through stripping.

[0055] In some more specific embodiments, the concentration of lithium ions in the anolyte in step (3) is above 0.05 mol / L.

[0056] Further, after step (3), if the concentration of lithium ions in the anolyte is lower than 0.05 mol / L, the anolyte is used as the extracted organic phase and applied to step (2) again.

[0057] In some more specific embodiments, the method also includes: enriching the ob...

Embodiment 1

[0073] (1) Mix N-butyl-N-methylpyrrole bis(trifluorosulfonyl)imide salt and butyl acetate at a volume ratio of 1:1, dissolve fluoro-benzo-12-crown-4, and form an extract The organic phase, wherein the concentration of fluoro-benzo-12-crown-4 is 0.1mol / L, and the preparation of lithium ion concentration is 15mol / L lithium chloride solution;

[0074] (2) Fully mix the extracted organic phase with the lithium chloride solution at a volume ratio of 1:1, and centrifuge to collect the lithium-loaded organic phase after shaking for 1 h;

[0075] (3) The organic phase loaded with lithium is used as the anolyte, the 0.1mol / L ammonium chloride solution is used as the catholyte, the pure copper electrode is used as the anode and the cathode, and the polypropylene film is used as the separator, and the electric field voltage per centimeter is 0.5V, constant Voltage direct current, collecting catholyte from 0h to 0.5h of electrification, 7 The abundance of Li is 92.65%;

[0076](4) The c...

Embodiment 2

[0078] (1) Mix 1-propyl-3-methylimidazolium bis(trifluorosulfonyl)imide salt and dichloromethane at a volume ratio of 1:10, dissolve tetraacetyl-benzo-15-crown-5, and form Extracting the organic phase, wherein the concentration of tetraacetyl-benzo-15-crown-5 is 10mol / L, and the concentration of lithium ions is 20mol / L to prepare a lithium bis(trifluoromethanesulfonyl)imide solution;

[0079] (2) Fully mix the extracted organic phase with the lithium bis(trifluoromethanesulfonyl)imide solution at a volume ratio of 1:20, shake for 0.5 h and centrifuge to collect the lithium-loaded organic phase;

[0080] (3) The organic phase loaded with lithium is used as the anolyte, the 0.01mol / L potassium chloride solution is used as the catholyte, the platinum electrode is used as the anode and the cathode, and the polyethylene film is used as the separator. The electric field voltage per centimeter is 4.0V, and the collected Catholyte for 8h ~ 16h, 7 The abundance of Li is 92.60%;

[00...

technical field

[0001] The invention belongs to the technical field of lithium isotope separation and enrichment, and specifically relates to an extraction-electromigration coupled separation and enrichment 7 Li isotope method. Background technique

[0002] High-abundance lithium isotopes play an important role in national economy and national defense security. More than 99.9% abundance 7 LiOH is an acidity regulator for pressurized water reactors, 7 LiBeF is the neutron moderator of the new molten salt reactor. 30%~90% abundance 6 Li is an indispensable raw material for fusion reactors and hydrogen bombs, and is also used in various neutron detectors. With the maturity of molten salt reactor and fusion reactor technology, domestic and foreign markets will demand 7 Li and 6 Li's demand will increase day by day. and 7 Li and 6 The natural abundances of Li are 92.5% and 7.5%, respectively, which cannot be directly applied to the above fields, and must be separated by...

Examples

preparation example Construction

[0051] Further, the preparation method of the lithium-loaded organic phase also includes: obtaining by directly dissolving lithium salt in the extracted organic phase or driving lithium ions into the extracted organic phase by an electric field.

[0052] Further, the concentration of lithium ions in the anolyte is above 0.05mol / L.

[0053] Further, when the concentration of lithium ions in the anolyte is lower than 0.05mol / L, a new anolyte can be replaced.

[0054] Furthermore, the anolyte with a lithium ion concentration lower than 0.05 mol / L can be reused through stripping.

[0055] In some more specific embodiments, the concentration of lithium ions in the anolyte in step (3) is above 0.05 mol / L.

[0056] Further, after step (3), if the concentration of lithium ions in the anolyte is lower than 0.05 mol / L, the anolyte is used as the extracted organic phase and applied to step (2) again.

[0057] In some more specific embodiments, the method also includes: enriching the ob...

Embodiment 1

[0073] (1) Mix N-butyl-N-methylpyrrole bis(trifluorosulfonyl)imide salt and butyl acetate at a volume ratio of 1:1, dissolve fluoro-benzo-12-crown-4, and form an extract The organic phase, wherein the concentration of fluoro-benzo-12-crown-4 is 0.1mol / L, and the preparation of lithium ion concentration is 15mol / L lithium chloride solution;

[0074] (2) Fully mix the extracted organic phase with the lithium chloride solution at a volume ratio of 1:1, and centrifuge to collect the lithium-loaded organic phase after shaking for 1 h;

[0075] (3) The organic phase loaded with lithium is used as the anolyte, the 0.1mol / L ammonium chloride solution is used as the catholyte, the pure copper electrode is used as the anode and the cathode, and the polypropylene film is used as the separator, and the electric field voltage per centimeter is 0.5V, constant Voltage direct current, collecting catholyte from 0h to 0.5h of electrification, 7 The abundance of Li is 92.65%;

[0076](4) The c...

Embodiment 2

[0078] (1) Mix 1-propyl-3-methylimidazolium bis(trifluorosulfonyl)imide salt and dichloromethane at a volume ratio of 1:10, dissolve tetraacetyl-benzo-15-crown-5, and form Extracting the organic phase, wherein the concentration of tetraacetyl-benzo-15-crown-5 is 10mol / L, and the concentration of lithium ions is 20mol / L to prepare a lithium bis(trifluoromethanesulfonyl)imide solution;

[0079] (2) Fully mix the extracted organic phase with the lithium bis(trifluoromethanesulfonyl)imide solution at a volume ratio of 1:20, shake for 0.5 h and centrifuge to collect the lithium-loaded organic phase;

[0080] (3) The organic phase loaded with lithium is used as the anolyte, the 0.01mol / L potassium chloride solution is used as the catholyte, the platinum electrode is used as the anode and the cathode, and the polyethylene film is used as the separator. The electric field voltage per centimeter is 4.0V, and the collected Catholyte for 8h ~ 16h, 7 The abundance of Li is 92.60%;

[00...