Method for preparing lithium carbonate through salt lake brine with high ratio of magnesium to lithium

Abstract

The invention relates to the field of salt lake resource comprehensive utilization, in particular to a method for preparing lithium carbonate through salt lake brine with the high ratio of magnesium to lithium. The salt lake brine with the high ratio of magnesium to lithium serves as a raw material, a certain amount of soluble trivalent metal salt is added, the ratio of magnesium to lithium in the salt lake brine is reduced by synthesizing magnesium-based stratified functional materials, magnesium and lithium in the salt lake brine with the high ratio of magnesium to lithium are separated, and then lithium carbonate is prepared through hydrotalcite mother liquor with the low ratio of magnesium to lithium. The technical problems that an existing method is complex in process, cost is high, and the magnesium and lithium separation effect is not ideal can be effectively solved through magnesium and lithium separation and lithium carbonate preparation methods, the lithium carbonate preparation process is simplified, cost is reduced, waste magnesium resources are fully utilized, and meanwhile the cost of the magnesium-based functional materials is reduced; high-valued and comprehensive utilization of salt lake magnesium, lithium and boron resources is achieved, and good industrialization prospects are achieved.

Description

technical field [0001] The invention relates to the field of comprehensive utilization of salt lake resources. Specifically, the invention relates to a method for preparing lithium carbonate from salt lake brine with a high magnesium-lithium ratio. Method for Lithium Preparation. Background technique [0002] Lithium is the lightest metal, known as "the energy metal that promotes the progress of the world". It has unique physical and chemical properties, and is a strategic resource of great significance in national economy and national defense construction. In nature, lithium resources mainly occur in solid ore and liquid brine. In the past, my country did not pay enough attention to lithium extraction from salt lake brine. Over the years, my country's lithium salt production is still dominated by lithium-containing ores such as spodumene and lepidolite. Because the extraction of lithium from salt lake brine has the advantages of large resources and low cost, and with the...

AI Technical Summary

Problems solved by technology

But this method produces hydrogen chloride gas in the production process, which is easy to corrode equipment, and the amount of evaporated water is large, high energy consumption, and high cost

Multi-stage membrane separation technology, in the reverse osmosis concentration process, the membrane is prone to clogging or damage, and the cost of using the membrane is relatively high

The key to the adsorption method is the adsorbent. Lithium-ion sieve-type manganese oxide and titanium oxide materials have been paid attention to, but their actual adsorption capacity is low, their permeability is poor, and there are problems of dissolution loss and granulation.

[0005] Chinese Patent Publication No. CN1579937A used salt lake brine to prepare nano-magnesium-aluminum hydrotalcite, and did not study the ratio of magnesium to lithium in salt lake brine and the preparation of lithium carbonate. The mother liquor after preparing nano-magnesium-aluminum hydrotalcite was alkaline and contained CO 3 2- , cannot be directly used in the production of products such as lithium carbonate, and the SO present in the mother liquor 4 2- and B are also not conducive to the enrichment of lithium and the preparation of lithium hydroxide

Chinese Patent Publication No. CN102602966A, adding recycled organic magnesium precipitating agent to salt lake brine, reacting crystallization to remove magnesium and enrich lithium to realize magnesium and lithium separation; magnesium chloride precipitating agent is recycled through separation and regeneration; impurity removal agent is added to the solution after magnesium removal , carry out deep impurity removal; finally, add carbonate to the lithium-rich solution after deep impurity removal, and precipitate lithium carbonate crystals. This method wastes magnesium resources, uses organic magnesium precipitants, pollutes salt lake resources, and increases cost

This method can obtain easily filterable magnesium hydroxide by adding seed crystals, controlling reaction conditions, etc., but requires a large amount of sodium hydroxide raw material