Method for extracting lithium from salt lake brine by extraction method

Abstract

The invention relates to a method for extracting lithium from salt lake brine by an extraction method. The method is suitable for a production process that lithium carbonate and lithium chloride are prepared from high magnesium-lithium ratio salt lake brine and concentrated old brine which contains lithium of salt pan. Co-extraction agent FeCl3, extraction agent and diluent are adopted to carry out lithium extraction, wherein the extraction agent is mixture of neutral phosphorus oxide compound A and phase modifier B, the phase modifier B is organic compound which can generate protonation reaction with the neutral phosphorus oxide compound A in an extraction reaction process, an extraction complex composition obtained after the extraction agent is used for lithium extraction is xLiFeCl4.yHCl.aA.bB, and the extraction complex can be easily dissolved in diluent; an extraction system has good phase splitting performance and reverse extraction and regeneration performance, and the lithium extraction technology of the extraction method is further optimized. The method has a low requirement on equipment, the adopted organic compound is cheap and can be easily obtained, and therefore, the method is suitable for industrial application.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a method for extracting lithium from salt lake brine by an extraction method. Background technique [0002] Lithium has various excellent properties, and is known as "the energy metal of the 21st century", "industrial monosodium glutamate", "tomorrow's aerospace alloy", and has a significant strategic position. Salt lake brine is an important resource of lithium. my country has abundant lithium resources of salt lake brine, and its reserves rank among the top in the world. Lithium extraction from brine produced abroad is limited to brine with low magnesium concentration, and the ratio of magnesium to lithium is less than 6:1. For the so-called "high-magnesium-lithium" salt lakes containing high-concentration magnesium and low-concentration lithium, such as my country's Qaidam Basin salt lake Separation and extraction of lithium from brine is a recognized worldwide techn...

AI Technical Summary

Problems solved by technology

The phase-inversion regeneration process of the organic phase of the extraction system is to shake the empty organic phase after hydrochloric acid back-extraction with quantitative sodium hydroxide, neutralize the acid in the organic phase, and then contact the raffinate to extract iron into the water phase. into the organic phase to make HFeCl 4 Converted to NaFeCl 4 , Mg(FeCl4) 2 , so that the extraction agent recovers the ability to extract lithium to complete the phase inversion process. During the phase inversion process, the amount of alkali added must be precisely controlled. If the amount of alkali added is too low, it will seriously affect the extraction capacity of the regenerated organic phase lithium. If the amount of alkali added is too high, the load Excessive alkali in the organic phase cannot be completely neutralized by the acid in the brine, which will seriously affect the phase separation effect and put forward high requirements for the control level of industrial production

On the whole, the existing salt lake brine extraction method still has complex process flow, high price of extraction reagents, high anti-corrosion requirements for extraction equipment, large investment, and high overall production cost.

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