Method for quasi-fractionation extraction and separation of sodium and potassium in lithium sulfate

Abstract

The invention discloses a method for extracting and separating sodium and potassium in lithium sulfate by quasi-fractionation, belonging to the technical field of solvent extraction. The 2N grade lithium sulfate solution after the alkaline earth metal impurities have been separated and removed is used as the feed liquid, t-BAMBP is used as the extractant, sulfonated kerosene is used as the diluent, lithium saponification t-BAMBP is used as the extraction organic phase, and the lithium sulfate feed solution is used for apparent washing Reagent, quasi-fractional extraction method to separate alkali metal impurities sodium and potassium in lithium sulfate. The lithium saponification organic phase enters the quasi-fractionation extraction system from the first stage, the lithium sulfate feed liquid enters the quasi-fractionation extraction system from the junction of the extraction section and the extraction section, and the apparent washing liquid enters from the last stage. Obtain the target product lithium sulfate solution from the first-stage outlet water phase, wherein the concentration of lithium is 1.0M~2.0M, the concentration of sodium is 2.5×10-7M~2.6×10-6M, and the concentration of potassium is 1.1×10-6M 8M~1.0×10‑7M. Concentrate and crystallize the obtained lithium sulfate solution to obtain hydrated lithium sulfate with a purity of 5N-6N. Compared with raw materials, the removal rate of sodium in the separated product is 99.978%-99.9969%, and the removal rate of potassium is 99.9983%-99.99957%.

Description

technical field [0001] The present invention relates to the method for quasi-fractionation extraction and separation of sodium and potassium in lithium sulfate, in particular to a lithium saponification t-BAMBP as the extraction organic phase, lithium sulfate stock solution as apparent detergent, quasi-fractionation extraction method for separating lithium sulfate solution The invention discloses a process method for sodium and potassium as impurities, belonging to the technical field of solvent extraction. Background technique [0002] Lithium functional materials are widely used in high-tech fields such as atomic energy, aerospace, defense industry, and optical instruments. Lithium sulfate with a purity higher than 99.99% is an important raw material for preparing high-performance lithium functional materials, so it is of great practical significance to research and develop a process for preparing lithium sulfate with a purity higher than 99.99%. [0003] The main alkali ...

AI Technical Summary

Problems solved by technology

Using traditional methods to separate alkali metal impurities in lithium sulfate has disadvantages such as high operating environment requirements, high labor intensity, poor separation effect, high production cost, low yield, and the purity of lithium sulfate is lower than 99.999%.

As of today, there are few reports on the preparation of lithium sulfate with a purity of 99.999% to 99.9999%.