Technology for extracting lithium from lithium-containing alkaline brine based on mixer settlers

Abstract

The invention discloses a technology for extracting lithium from lithium-containing alkaline brine based on mixer settlers. The technology includes the following steps that an extraction water phase is provided; an extraction organic phase is provided; extraction is conducted; washing is conducted; back extraction is conducted; and regeneration is conducted. According to the technology, a brand new extraction system is adopted, the lithium is extracted from a lithium-containing alkaline brine system, in addition, an extraction-washing-back extraction-regeneration total-process technology basedon the mixer settlers is determined for the first time, people not only rest on the fundamental research of an extraction section, finally, technological parameters matched with the extraction systemare determined, and an industrial production technological path based on the mixer settlers is provided, wherein the technological parameters include the stage number of each section, the flow ratioand the concentration of all reagents. The technology for extracting the lithium from the lithium-containing alkaline brine is particularly suitable for a filter liquid system generated in the processthat a lithium chloride solution is used for preparing a lithium carbonate product, so that the lithium is further extracted from the filter liquid system, true comprehensive recycling of salt lake brine is achieved, and the practical significance is achieved.

Description

technical field [0001] The invention belongs to the technical field of salt lake chemical industry, and specifically relates to a process for extracting lithium from lithium-containing alkaline brine based on a mixing and settling tank. Background technique [0002] Lithium is the lightest metal in nature and has extremely strong electrochemical activity. Its metals and compounds are widely used in glass, ceramics, aluminum smelting, organic chemical industry, aerospace, nuclear fusion and other industries and fields as thermonuclear fusion (hydrogen bomb) explosives, high-performance propellant for aircraft, rockets and missiles, and shielding materials for nuclear reactors. Lithium batteries have 4 to 30 times higher energy storage than ordinary batteries and have good performance. They have long been used as propulsion for torpedoes, submarines, and spacecraft. Lithium-aluminum and lithium-magnesium alloys are high-strength and light-weight, and are good materials for ae...

AI Technical Summary

Problems solved by technology

[0003] At present, effective methods for extracting lithium from salt lake brine include solvent extraction, and solvent extraction inevitably uses FeCl 3 As a co-extraction agent, the density of the extracted organic phase is increased, and the density difference between the two phases is reduced, which requires higher extraction and separation equipment; at the same time, the introduction of FeCl 3 Finally, it is very difficult to regenerate the extractant with alkali, and very precise flow control is required, otherwise it will cause problems such as a decrease in extraction rate or emulsification failure of the extractant

In addition, since the organic phase contains co-extractant FeCl 3 , this requires that the extraction material (brine) must be kept weakly acidic, otherwise Fe will be hydrolyzed, and the brine entering the extraction section must be acidified. Lithium and boron generally exist together in Qinghai Salt Lake, and boric acid must be precipitated during the acidification process. Filtration is required, so it is not suitable for the extraction of lithium in alkaline systems

Moreover, most of the extraction agents currently used for lithium can only achieve the separation of lithium and magnesium, and the extraction effect for alkali metal systems is very poor.

In short, due to the existence of the co-extraction agent FeCl3, the process flow is more complicated, the process control is very difficult, and the investment in equipment is large.

[0004] At the same time, among the extraction equipment currently used in the solvent extraction industry, although the centrifugal extractor has the advantages of compact equipment, high mass transfer efficiency, small solute retention, short extraction process equilibrium time, less material retention, rapid phase separation, and parameter adjustment There are many advantages such as rapid response and easy automation, but it also has disadvantages such as high cost, difficult operation, and difficult maintenance; while the mixing and settling tank has the advantages of simple operation and low equipment cost, which can be used to overcome the shortcomings of the above-mentioned centrifugal extractor

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