Issue 17, 2024

Selective lithium extraction from brine via chemical reduction of iron phosphate with aqueous iron compounds

Abstract

Worldwide demand for lithium (Li) is surging due to increased production of Li-ion batteries to meet the needs for increasing numbers of electric vehicles and stationary energy storage systems. Conventional Li+ extraction from Li-bearing ores and brines has drawbacks of high chemical and energy inputs. In this work, chemical redox-driven processes were developed to selectively extract Li+ from brine meant to simulate a geothermal resource. Using additives that modify the redox potential of soluble iron compounds, ethylenediaminetetraacetic acid (EDTA) and citrate, the potential of the solution was shifted lower to drive reduction of a targeted solid electroactive material (FePO4, FP). Li+ from simulated brine sources (with molar ratio Li+ : Na+ of 1 : 78) was extracted into the FP solid without additional energy inputs. The Li+ adsorption capacity for extraction with EDTA–Fe2+ solutions and citrate–Fe2+ solutions were 3.8 mmol Li+ g−1 FP and 2.5 mmol Li+ g−1 FP, respectively, and the selectivity factors for Li+ to Na+ for the two systems were 78 and 350, respectively. Similar extraction outcomes were achieved using a brine that more closely resembled the composition of geothermal fluids from the Salton Sea. This study more broadly provided insight into enhancing Li+ capture selectivity through modification of redox solution compositions.

Graphical abstract: Selective lithium extraction from brine via chemical reduction of iron phosphate with aqueous iron compounds

Supplementary files

Article information

Article type
Paper
Submitted
25 May 2024
Accepted
04 Jul 2024
First published
17 Jul 2024
This article is Open Access
Creative Commons BY license

Sustainable Energy Fuels, 2024,8, 3902-3916

Selective lithium extraction from brine via chemical reduction of iron phosphate with aqueous iron compounds

J. Wang, A. W. Hawkins, A. T. Saasi, C. G. Morin, G. M. Geise and G. M. Koenig, Sustainable Energy Fuels, 2024, 8, 3902 DOI: 10.1039/D4SE00703D

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