Recovery of lithium from underground brine by multistage centrifugal extraction using tri-isobutyl phosphate

Abstract

The recovery of lithium from brine is a focus of worldwide due to the increasing demand of lithium in modern energy industry. Multistage centrifugal extraction was used in this work to recover lithium from underground brine. It was found that the centrifugal extraction rate of lithium is low by conventional methods, during which a multimolecular reaction with slow equilibrium time is involved. This problem was successfully solved by using an extraction system containing 80% tri-isobutyl phosphate (TIBP) and 20% sulfonated kerosene in combination with a novel operating method. The recycling of co-extractant (Fe3+) which is one of the bottleneck problems to limit the application of solvent extraction was also solved based on an innovative technical process. The recovery rate of lithium in underground brine reached to 90.05% by five-stage centrifugal extraction at optimized conditions. The stripping rate of lithium in organic phase was almost 100% using a solution containing 1.0 mol/L HCl at R(O/A) = 2:1. Lithium was not only separated from brine but also fourfold concentrated without any washing of the organic phase. This developed method is simple and thus is promising to be applied for the industrialized recovery of lithium from underground brine.