Ion rectification method for preparing lithium chloride from salt lake brine

Abstract

The invention discloses an ion rectification method for preparing lithium chloride from salt lake brine. According to the method,an ion rectification system is adopted, and the ion rectification system is formed by sequentially laminating a plurality of monovalent and multivalent cation selective membranes and a plurality of monovalent and multivalent anion selective membranes according to the principle that the same kind of membranes is arranged at the same side, and then adding a flow channel separation net and a sealing gasket; chloride ions and lithium ions are selectively screened by the plurality of multivalent anion selective membranes and the multivalent cation selective membranes respectively, impurity anions and cations are selectively blocked at the same time; and finally, through n-stage selective separation, the stage number of the selectivity coefficient among the chloride ions, the lithium ions and the impurity ions is amplified, and therefore, efficient extraction of the lithium chloride is realized in a single electrodialysis membrane assembly. According to the method of the invention, the selectivity coefficient of the lithium ions and the chloride ions is determined by the number of the monovalent and multivalent cation selective membranes and the monovalent and multivalent anion selective membranes which are used in a laminated manner, so that the requirement on the characteristics of a special diaphragm is greatly reduced, and the purity and the quality of a salt lake lithium extraction product are greatly improved.

Description

technical field [0001] The invention belongs to the field of electrically driven membrane separation, in particular to an ion distillation method for preparing lithium chloride from salt lake brine. Background technique [0002] Special ion separation is an important chemical separation technology, which occupies an important position in the field of lithium extraction from salt lakes. Lithium is the lightest metal with extremely strong electrochemical activity. Its metals and compounds have been rapidly developed in the fields of high-energy lithium batteries, nuclear fusion power generation, aerospace, ceramics, lasers, and medicine. From the perspective of economic development and national security, many countries have taken it as a strategic material reserve and carried out applied technology research, and all countries in the world have also attached great importance to the development of lithium resources. The reserves of lithium resources in my country ranks second i...

AI Technical Summary

Problems solved by technology

Therefore, in the selective electrodialysis process, the separation performance of special ions still depends on the screening characteristics of the functional membrane itself, and the unsatisfactory screening performance of the functional membrane also limits the separation efficiency of target ions.

[0006] Similar to the traditional special ion separation process, such as ion exchange, solvent extraction, ion sieve adsorption, etc., the industry needs to achieve the target screening of lithium ions through the coupling and integration of multiple selective electrodialysis units. At this time, selective electrodialysis itself The characteristics of continuous operation cannot be effectively reflected

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