Method for extracting lithium from salt lake brine and preparing aluminum hydroxide simultaneously

Abstract

The invention provides a method for extracting lithium from salt lake brine and preparing aluminum hydroxide simultaneously. The method comprises process steps as follows: aluminum salt is added to brine and subjected to a coprecipitation reaction with alkali liquor to obtain MgAl-LDH and lithium-containing brine; the lithium-containing brine is subjected to evaporation concentration, solid aluminum chloride is added to the lithium-containing brine and subjected to a coprecipitation reaction with a sodium hydroxide solution, a lithium-containing layered structure material is prepared and dispersed in deionized water, heating is performed under full stirring, so that lithium ions are removed from solids of the lithium-containing layered structure material to enter an aqueous solution, and the solution is concentrated to reach the lithium carbonate preparation concentration; aluminum is still retained in a solid phase and an aluminum hydroxide product is obtained. Lithium is extracted from the lithium-containing layered structure material, the reaction is mild, the equipment is simple, the lithium loss is low, mass production is easy, and an important way is provided for extraction of the lithium resource. The sodium hydroxide product is coproduced while the lithium is extracted efficiently, and comprehensive utilization of lithium and aluminum resources is realized.

Description

technical field [0001] The invention relates to the field of separation and extraction of lithium resources, in particular to the use of reaction-separation coupling technology to pass lithium-containing layered structure material LiAl from salt lake brine x (OH) 3x Cl mH 2 A method for extracting lithium with O (x=1-10, m=1-10) and simultaneously preparing aluminum hydroxide. Background technique [0002] Lithium-ion secondary batteries have been widely used in mobile phones, notebook computers, new energy vehicles and energy storage fields due to their advantages such as large capacity, long life, no environmental pollution, and safe use. Especially with the increasingly serious global energy crisis, the development of new energy vehicles has become an important part of the national strategy. Benefiting from the full-scale outbreak of the new energy vehicle market, the global lithium demand is gradually increasing. [0003] In 2018, the results of the US Geological Sur...

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Problems solved by technology

The calcination method is a relatively mature method in the lithium extraction technology of salt lake brine, but the energy consumption is high, and the acid mist discharge will cause air pollution; the adsorbent method is a more promising method, because of its simple process and high recovery rate, it is economical and environmentally It is considered that it has greater advantages than other methods, but the problems in the adsorption method include the difficulty in recovering the adsorbent, the reduction of the adsorption capacity due to the blockage of ion channels, and the dissolution of the adsorbent in the acid treatment process; the extraction method uses organic solvents to treat Li + For selective extraction, there are problems such as large equipment volume, serious corrosion, difficult recovery of extractant, and heavy pollution; membrane method is a new technology for extracting lithium from brine, mainly including electrodialysis, nanofiltration and membrane distillation, and the energy cost is relatively low. Low, and has good cation selectivity, but currently lacks high-efficiency separation membrane materials in China, and needs to rely on imports

[0007] The patent (CN 105152193A) discloses a process for efficiently separating Mg and Li in salt lake brine by using reaction / separation coupling technology, and simultaneously producing magnesium aluminum hydrotalcite (MgAl-LDH) and lithium aluminum hydrotalcite (LiAl-LDH), but the preparation The obtained LiAl-LDH cannot directly produce lithium products such as lithium carbonate and lithium hydroxide