Method for extracting lithium from magnesium-removal bittern and preparing battery-grade lithium carbonate

Abstract

The invention discloses a method for extracting lithium from magnesium-removal bittern and preparing battery-grade lithium carbonate. The method uses a reaction-separating coupling technology for separating, extracting a lithium resource from magnesium-removal bittern and generating the battery-grade lithium carbonate, a technology comprises the following steps: aluminium salt is added in high sodium bittern after magnesium removal, and steps of nucleation and crystallization are carried out with alkali lye in a colloid grinder to obtain a lithium-aluminium composite metal hydroxide solid, lithium ions are introduced into a solid phase, the sodions stay in a solution, so that lithium ions and sodions are effectively separated. The lithium-aluminium composite metal hydroxide is dissolved by acid to obtain a solution containing lithium ions and aluminum ions, then lithium and aluminium are separated by an electrodialysis apparatus, the separated solution containing aluminium can be recycled, a lithium-rich solution is subjected to a precipitation reaction, and the battery-grade lithium carbonate is obtained. A reaction-separation coupling technology is used, while lithium and sodium are separated, the battery-grade lithium carbonate is prepared, so that high efficiency and high value utilization of the salt lake lithium resource can be realized.

Description

technical field [0001] The invention relates to the field of utilization of brine resources, in particular to a process for separating and extracting lithium resources in salt lake brine after magnesium removal by using reaction-separation coupling technology and producing battery-grade lithium carbonate. Background technique [0002] Salt lakes usually refer to lakes with a salt content greater than 50g·L -1 lakes, which contain a large amount of Cl - , SO 4 2- 、HCO 3 - , CO 3 2- 、Na + 、K + , Mg + , Li + Ions, with a salt content exceeding 24.7‰, are important raw materials for the production of various industrial and agricultural products. As the amount of lithium used in traditional applications continues to grow, people are also continuing to develop new applications, and the demand for lithium resources is also increasing. As a new type of energy and strategic resource, lithium has attracted much attention in the 21st century. China's salt lake lithium reso...

AI Technical Summary

Problems solved by technology

[0005] Chinese Patent Publication No. CN 105152193 A is an industrial method for extracting magnesium and lithium from brine and producing hydrotalcite at the same time. There is no research on the preparation of lithium carbonate. The mother liquor after the preparation of magnesium aluminum hydrotalcite contains various ions, especially high content of sodium ions , cannot be directly used in the production of products such as lithium carbonate

[0006] Chinese Patent Publication No. CN 105036159 A is a method for preparing lithium carbonate from high-lithium salt lake brine, adding additives, complexing agents and precipitating agents when preparing lithium carbonate, wherein the complexing agent is EDTA or tartaric acid, and the additive added is lithium carbonate Crystal, this method increases production cost because of adding lithium carbonate

[0007] Chinese Patent Publication No. CN 105152191 A is a method for preparing lithium carbonate by using high magnesium-lithium ratio salt lake brine. In the mother liquor after preparing magnesium-aluminum hydrotalcite, acid is added to adjust the pH to remove CO in the mother liquor. 3 2- , followed by multi-step operation to add acid to remove CO 3 2- , and finally added carbonate when preparing lithium carbonate, wasting carbonate in the preparation process

Images