A method for extracting lithium from salt lake brine using hollow fiber forward osmosis membrane

Abstract

The invention discloses a method for extracting lithium from salt lake brine by using a hollow fiber FO (forward osmosis) membrane. The method comprises the steps as follows: surface activity modification of a hollow fiber base membrane, preparation of the hollow fiber FO membrane through layer-by-layer self-assembly and FO concentration of salt lake brine for lithium enrichment. An assembly is prepared from the hollow fiber FO and applied to multistage processes such as concentration of the salt lake brine for lithium enrichment. The hollow fiber FO membrane prepared with the method has highsalt resistance and higher retention rate. The preparation technology of the base membrane is simple, low in cost, low in consumption of functional layer materials, convenient to operate and easy to control. A membrane polarized layer is high in charge density, wide in applicable brine salinity range and high in concentration multiple. The operation mode that a selection layer faces a low-concentration brine lithium extraction raw material liquid (FO mode) is adopted, old salt lake brine, a salt lake tedded composite salt solution and a concentrated solution at a multistage nanofiltration process section for lithium extraction from the salt lake brine are taken as extraction liquids, the energy consumption and the production cost are low, the lithium loss rate is small, and the membrane isstable in performance, easy to clean and long in service life.

Description

technical field [0001] The invention belongs to the field of membrane preparation and application thereof, and in particular relates to a preparation method using a hollow fiber forward osmosis membrane and a method for extracting lithium in salt lake brine. Background technique [0002] With the development of the new energy industry, lithium resources are increasingly valued as an energy metal in the 21st century. Salt lake brine lithium resources account for 91% of the world's total lithium resources. Extracting lithium from salt lake brine with high efficiency and low cost has gradually become the development of lithium industry at home and abroad. Concerns in the production of lithium salts. At present, the reverse osmosis, nanofiltration and other membrane separation technologies involved in the salt lake brine lithium extraction process are all pressure-driven filtration, which has high energy consumption, serious membrane pollution, high operating costs, and limited ...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the disadvantages of existing hollow fiber forward osmosis membranes, such as complex preparation process, large consumption of raw materials, uncontrollable polarized layer thickness, low charge density, small water flux, high reverse salt flux, etc. In order to solve the current situation of lithium extraction technology in salt lake brine, a production technology of hollow fiber forward osmosis membrane suitable for concentration, enrichment and lithium extraction of high-salt brine was proposed by layer-by-layer self-assembly method.