Energy-saving and environmentally-friendly salt lake brine lithium extracting technology

Abstract

The invention discloses an energy-saving and environmentally-friendly salt lake brine lithium extracting technology. The technology comprises the steps of atomizing and forcibly evaporating high-salinity brine through a tower type reinforcing atomizing circulating concentrating and salt separating device, thus realizing high-multiple concentration and salt reducing and lithium enriching of the brine; processing the concentrated lithium-enriched brine by multi-stage high-pressure nanofiltration to realize salt separating and magnesium removing; retuning the primary nanofiltration low-lithium concentrated water to a tower type concentrating liquid inlet part; extracting lithium from the lithium-enriched nanofiltration water in a liquid-liquid extraction manner; returning lithium-containing raffinate water phase and extracting agent regenerating washing liquid to a nanofiltration liquid inlet part, and further recovering lithium; evaporating high-lithium reverse extraction liquid, and recovering acid for regenerating an extraction additive; evaporating to remove acid to obtain solid high-lithium compound salt; performing solid-liquid extraction through ethyl alcohol; volatilizing theobtained lithium chloride ethyl alcohol extracting solution; and recovering ethyl alcohol to obtain high-purity lithium chloride. The technology is obvious in energy saving effect in the whole process, high in lithium recovery rate, low in production cost, safe, environmentally friendly, and applicable to extraction and production of lithium in various types of high-salinity and high-magnesium-lithium-ratio salt lake brine.

Description

technical field [0001] The invention belongs to the technical field of wet extraction of rare and precious metals, in particular to an energy-saving and environment-friendly process for extracting lithium from salt lake brine. Background technique [0002] Salt lake brine is one of the main ways to develop lithium resources. The main methods for extracting lithium from brine include: precipitation method, adsorption method, extraction method, membrane method, etc. However, the existing lithium extraction processes have defects such as high production cost, high energy consumption, and serious secondary pollution. Therefore, under the current national policy trend of highly advocating environmental protection, it is imperative to develop an energy-saving and environmentally friendly lithium extraction process. [0003] At present, the most common method of concentration and separation of brine is to use solar energy to separate part of the monovalent salt through drying in ...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a forced circulation spray concentration desalination lithium rich + high pressure nanofiltration desalination magnesium + The combination process of liquid-liquid extraction of rich lithium + solid-liquid extraction of lithium chloride includes the following steps: high-salinity brine passes through a tower-type heat-intensified spray circulation concentration and salt separation device, and the brine is atomized and forced to evaporate to make sodium, potassium, and magnesium Due to supersaturation, precipitation and crystallization, the chloride and sulfate in the brine can be concentrated at a high rate and reduce salt and enrich lithium; the concentrated lithium-rich brine is separated by multi-stage high-pressure nanofiltration to separate salt and remove magnesium, and the primary nanofiltration low-lithium concentrated water Return to the tower-type concentration inlet to reduce lithium loss; lithium-rich nanofiltration product water liquid-liquid extraction extracts lithium, lithium-containing raffinate aqueous phase and extraction agent regeneration cleaning solution return to nanofiltration inlet to further recover lithium; Recovery of acid by evaporation of lithium stripping solution for regeneration of extraction aid

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