Technology for extracting lithium from alkaline bittern

Abstract

The invention discloses a technology for extracting lithium from alkaline bittern. The technology comprises the following steps of supplying an aqueous phase extraction, supplying an organic phase extraction, extracting, washing, reverse extracting and regeneration. The technology adopts an extraction system different from the tradition, and can extract lithium from an alkaline bittern system, meanwhile a complete process comprising the steps of extraction, washing, reverse extraction and regeneration is determined for the first time while not staying at basic researching of an extraction section, technology parameters such as the series of each section, the phase ratio and the concentration of each agent matched with the extraction system are finally determined, and a basic technology route is provided for industrialized expanded production. The technology for extracting lithium from the alkaline bittern is particularly suitable for a system that filter liquid is generated in the preparation process of a lithium carbonate product by using a lithium chloride solution, so that lithium is further extracted from the alkaline filter liquid bittern system where lithium carbonate is saturated, accordingly rear comprehensive cyclic utilization of salt lake bittern can be achieved, and the technology has practical meaning.

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 alkaline brine. 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 aerospace and rockets, and are favored by the military an...

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 FeCl3 as the The co-extraction agent increases the density of the extracted organic phase and reduces the density difference between the two phases. It requires high extraction and separation equipment. The traditional mixing and settling tank is difficult to meet the process requirements. High-efficiency centrifugal extraction equipment must be used, which is expensive; at the same time , after the introduction of FeCl3, 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.

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