Salt lake lithium extraction system and method based on membrane separation

Abstract

The invention relates to the technical field of salt chemical industry, and particularly relates to and discloses a salt lake lithium extraction system based on membrane separation. The system comprises a magnesium removal system, a boron removal system, a lithium carbonate preparation system and a lithium precipitation mother liquor recycling system which are connected in sequence; themagnesium removal system comprises a nano-filtrationmagnesium removal unit; the boron removal system comprises a reverse osmosis boron removal unit and an electrodialysis boron removal concentration unit, which are connected in sequence; the lithium carbonate preparation system comprises an MVR concentration unit and a lithium precipitation unit, which are connected in sequence; and the lithium precipitation mother liquor recycling system comprises lithium absorption resin and a bipolar membrane electrodialysis unit, which are connected in sequence. The invention also discloses a salt lake lithium extraction method based on membrane separation. The method comprises the following steps: 1) deeply removing magnesium; 2) deeply removing boron; 3) preparing lithium carbonate; and 4) recycling the lithium precipitation mother liquor. The salt lake lithium extraction system and method based on membrane separation have the advantages that no extra pollution is generated, the cost is saved, the energy consumption is reduced, the product purity is high, the production cost is low, and the pollution degree is low.

Description

technical field [0001] The invention relates to the technical field of salt chemical industry, in particular to a system and method for extracting lithium from salt lakes based on membrane separation. Background technique [0002] Lithium is widely used in batteries, ceramics, glass, lubricants, refrigerants, nuclear industry, and optoelectronic industries. With the continuous development of electronic products such as computers, digital cameras, mobile phones, and mobile electric tools, the battery industry has become the largest consumer of lithium. In recent years, the application of lithium in the battery field has grown the fastest, rising from 7% in 1997 to 35% in 2013. Now, with the continuous maturity of electric vehicle technology, lithium batteries will also be widely used in the automotive industry. The demand for lithium has grown further. [0003] At the beginning of the 20th century, it was a mainstream way to produce refined lithium ore through pegmatite ore...

AI Technical Summary

Problems solved by technology

[0004] The development techniques of lithium resources in salt lake brine mainly include solvent extraction method, precipitation method, ion exchange adsorption method and membrane separation technology, etc. The above methods can effectively recover lithium resources in salt lake brine, but there are also certain limitations, such as The extraction agent used in the solvent extraction method is an organic solvent. The use of a large amount of organic solvent will not only severely corrode the equipment, but also cause pollution to the surrounding environment; the precipitation method has the advantages of simple operation and low cost, but at the same time The use will introduce new impurities and increase the difficulty of subsequent treatment; the ion exchange method has a better removal or extraction efficiency for a certain ion, but there are still problems such as low adsorption capacity and high cost of the adsorbent; membrane separation technology is an emerging The separation technology is divided into ultrafiltration, nanofiltration, reverse osmosis and other technologies. Nanofiltration can effectively separate monovalent and high-valent salts, and reverse osmosis can achieve high concentration of salt solution and reuse of reclaimed water, but membrane separation technology is still relatively expensive high

Images