Method for extracting lithium from salt lake brine

Abstract

The invention provides a method for extracting lithium from salt lake brine. The method comprises the following steps: 1) preparing extract organic phases which comprise a composite extracting agent and a diluent, wherein the composite extracting agent is prepared by mixing tributyl phosphate with N,N-bis(2-ethylhexyl)-3-butanone acetamide according to a volume percent ratio of 50% to 50%; the diluent is sulfonated kerosene; 2) preparing an extract water phase which is an LiCl-MgCl2-H2O system; 3) adding HCl and FeCl3.6H2O to the extract water phase, wherein the ratio of amount of substances of iron and lithium is controlled to be 1.3 to 1, the acid concentration is 0.5mol/L, and the lithium concentration is 1-3g/L; 4) standing after fully mixing the extract water phase obtained in the step 3) with the extract organic phases obtained in the step 1) in a volume ratio of 1 to 2, and then separating a liquid phase. By adopting the method, the problems that the corrosivity of high-concentration tributyl phosphate towards extraction equipment is stronger and the dissolution loss of the extracting agent in water is serious in long-term operation are solved, and the lithium extraction efficiency of the prior art is achieved. The extraction method is simple and reliable to operate.

Description

technical field [0001] The invention belongs to the technical fields of extraction chemistry and chemical industry, and in particular relates to a method for separating lithium from a salt lake brine solution by using a composite extractant. Background technique [0002] my country is rich in salt lake resources, and the salt lake brine is rich in various minerals, which is also an important source of lithium. The reserves of lithium resources in brine in my country rank among the top in the world. However, salt lake brine contains a variety of metal ions, how to separate and extract lithium from it is an important topic of current research. [0003] Lithium not only has important applications in the defense industry, but also has become increasingly important in the national economy, especially in the energy field: 6 Li and 7 Li is an important material for fuel in future nuclear fusion reactors and for nuclear fission reactions, respectively; it is also in increasing dem...

AI Technical Summary

Problems solved by technology

However, this system needs to use high concentration of tributyl phosphate, which is highly corrosive to the extraction equipment, and the extraction agent is not only severely dissolved in water during long-term operation, but also in acidic medium, tributyl phosphate is prone to degradation , especially its severe swelling effect on the materials used to make extraction equipment limits its large-scale industrial application