Method for lithium recovery by extraction-stripping separation and purification

Patent metadata

Field	Value
Publication number	US-12480179-B2
Application number	US-202017773593-A
Country	US
Kind code	B2
Filing date	Oct 29, 2020
Priority date	Nov 1, 2019
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

The present disclosure relates to a method for lithium recovery by extraction-stripping separation and purification, including: (1) performing an extraction on a lithium-containing solution using an extraction system including a composite extractant at a pH in a range of 10-13 and separating to obtain a lithium-loaded organic phase; (2) subjecting the lithium-loaded organic phase obtained in step (1) to a gas-liquid-liquid three-phase stripping to obtain a lithium-loaded stripping solution; and (3) subjecting the stripping solution obtained in step (2) to a thermal treatment and separating to obtain a lithium product and a separated mother liquor.

First claim

What is claimed is:

1 . A method for lithium recovery by extraction-stripping separation and purification, comprising:
(1) performing an extraction on a lithium-containing solution using an extraction system comprising a composite extractant at a pH in a range of 10-13 and separating to obtain a lithium-loaded organic phase; (2) subjecting the lithium-loaded organic phase obtained in step (1) to a gas-liquid-liquid three-phase stripping to obtain a lithium-loaded stripping solution; and (3) subjecting the stripping solution obtained in step (2) to a thermal treatment and separating to obtain a lithium product and a separated mother liquor; wherein the gas-liquid-liquid three-phase comprises a gas phase, a first liquid phase, and a second liquid phrase; in step (2), the gas-liquid-liquid three-phase stripping is controlled at a pH in a range of 6-9; and in step (2), the gas phase comprises an acid gas, and the acid gas is introduced continuously; wherein in step (2), the gas-liquid-liquid three-phase stripping is operated in a multi-stage continuous countercurrent mode; an equipment for the gas-liquid-liquid three-phase stripping comprises any one of a continuous mixing clarification tank, an extraction tower or a centrifugal extractor; a stage number of the gas-liquid-liquid three-phase stripping is adjustable between 1 and 10; and in step (2), a concentration of lithium in the stripping solution is more than 5 g/L.

2 . The method according to claim 1 , wherein in step (1), the composite extractant comprises a neutral extractant and a chelating extractant, and the extraction system comprises the composite extractant and a diluent;
the neutral extractant comprises any one or a combination of at least two selected from the group consisting of tributyl phosphate, di (1-methylheptyl) methyl phosphonate, trioctylphosphine oxide, trioctyl/trihexyl phosphine oxide, and N,N-di (1-methyl heptyl) acetamide; and the chelating extractant comprises any one or a combination of at least two selected from the group consisting of 2-hydroxy-5-nonylacetophenone oxime, dodecyl phenyl-methyl-β-diketone, and 2-hydroxy-5-nonylbenzaldehyde oxime.

3 . The method according to claim 2 , wherein a volume ratio of the neutral extractant to the chelating extractant is in a range of 0.2:1-2:1.

4 . The method according to claim 1 , wherein the extraction system further comprises a phase modifier.

5 . The method according to claim 4 , wherein the extraction system comprises a composite extractant, a phase modifier and a diluent; a volume percentage of the composite extractant in the extraction system is in a range of 5-30%, and a volume percentage of the phase modifier is in a range of 0-10%.

6 . The method according to claim 1 , wherein in step (1), the lithium-containing solution comprises any one or a combination of at least two selected from the group consisting of lithium ore leaching solution, lithium-precipitated mother liquor, lithium battery waste leaching solution and salt lake brine;
a concentration of lithium in the lithium-containing solution is in a range of 0.25-5 g/L; concentrations of main impurity elements of sodium, potassium and boron in the lithium-containing solution are independently in ranges of 10-150 g/L, 0-50 g/L and 0-10 g/L, respectively; the lithium-containing solution further comprises metal ions, and the metal ions are selected from the group consisting of rubidium ions, aluminum ions, magnesium ions, cesium ions and calcium ions; wherein a volume ratio of the lithium-containing solution to the organic phase of the extraction system is in a range of 0.2:1-5:1; and in step (1), a concentration of lithium in the lithium-loaded organic phase is in a range of 0.5-3 g/L.

7 . The method according to claim 1 , wherein step (1) further comprises washing the lithium-loaded organic phase; and wherein a washing solution is water and/or a lithium-containing solution.

8 . The method according to claim 1 , wherein the acid gas in the gas phase comprises any one or a combination of at least two selected from the group consisting of SO 2 , SO 3 , CO 2 and Cl 2 .

9 . The method according to claim 8 , wherein the acid gas in the gas phase is SO 2 and/or CO 2 .

10 . The method according to claim 1 , wherein the first liquid phase comprises water.

11 . The method according to claim 1 , wherein the second liquid phase comprises the lithium-loaded organic phase.

12 . The method according to claim 1 , wherein a volume ratio of the first liquid phase to the second liquid phase is in a range of 0.05:1-2:1.

13 . The method according to claim 1 , wherein in step (3), the thermal treatment is performed by any one or a combination of at least two selected from the group consisting of oxidation, evaporative crystallization and thermal decomposition;
the thermal treatment is performed at a temperature in a range of 60-90° C.; the thermal treatment is performed for 0.5-2 h; an oxidant used in the oxidation comprises air, oxygen and ozone gas; the evaporative crystallization is performed by MVR or multi-effect evaporation; and the thermal decomposition is performed in a closed or semi-closed container.

14 . The method according to claim 1 , wherein in step (3), the separation is performed by any one or a combination of at least two selected from the group consisting of filtration, suction filtration and centrifugation.

15 . The method according to claim 1 , wherein the lithium product comprises lithium sulfate, lithium chloride or lithium carbonate, and the product has a purity of higher than 96%.

16 . The method according to claim 1 , wherein in step (3), the separated mother liquor is returned to step (1) and/or the first liquid phase in step (2).

Assignees

• Inst Process Eng Cas
• Shanghai Yiding New Material Tech Co Ltd

Inventors

• Qi Tao
• Zhu Zhaowu
• Zhang Jian
• Lin Daoyong

Classifications

• C22B3/04

  by leaching (C22B3/18 takes precedence) · CPC title

• C22B3/37 Primary

  containing boron, silicon, selenium or tellurium · CPC title

• C22B26/12 Primary

  Obtaining lithium · CPC title

• C22B7/006 Primary

  Wet processes · CPC title

• C22B3/40

  Mixtures · CPC title