243 Critical Mineral Resources and Recovery in the Americas: Emerging Methods in Exploration and Sustainable Extraction, Part I

This session explores the role of critical minerals in technology and the low-carbon economy, focusing on geological discoveries, sustainable extraction methods, and recycling to support secure, environmentally responsible mineral supply chains in the Americas.

Wednesday, 22 October 2025
8:00 AM - 12:00 PM
HBGCC, 217A

Ion exchange type Direct lithium extraction for Li recovery from sedimentary brines using modified lithium manganese oxide

Paper number: 243-3
Program: Technical Sessions
Time: 8:40 AM – 8:55 AM

Authors

Abstract

Previously unusable lithium (Li) sources, such as sedimentary brines, contain considerable Li reserves, with new exploration methods having identified regions of relatively high Li concentration. However, many of these brines contain high Mg/Li ratios and are therefore unsuitable for Li recovery using conventional solar evaporation/precipitation methods. Ion-exchange type Direct Lithium Extraction (i-DLE) have both high Li selectivity and high adsorption capacity, even in hypersaline brines. Among these, Lithium Manganese Oxide (LMO) can selectively separate Li from the other ions in solution because of its ion sieving capability, enabling rapid transport of Li into the material. One of the major problems with the commercial implementation of LMO is substantial dissolution of Mn2+ during sorbent delithiation with acid. This is primarily caused by reducing agents in the brine such as dissolved organic compounds and H2S. These compounds reduce Mn4+ at the LMO surface and convert it into Mn3+ during sorbent lithiation. Subsequently, disproportionation of the Mn3+ occurs during the Li recovery process in acid, converting Mn3+ into water soluble Mn2+ species, and leading to sorbent loss. In this study, we mitigated the conversion of Mn4+ to Mn3+ during Li adsorption by coating LMO with 7.5 nm of zirconium dioxide to inhibit contact between the reducing agents in the brine and Mn4+ ions at the LMO surface. Results showed that in a hypersaline sedimentary water containing organic compounds and traces of H2S, Li uptake reached 24 mg·g-1 in 1 h. LMO mounted into a polyvinylidene fluoride (PVDF) binder achieved a Li uptake of 20 mg·g-1 in 6 h. Importantly, the Mn loss per cycle, which was as high as 4.5% in the unmodified LMO, decreased by approximately 50% using the 7.5 nm zirconium coating, and by 90% using the PVDF binder. X-ray absorption spectroscopy confirmed that there were no measurable structural changes in the LMO after 16 cycles, supporting a theoretical sorbent recyclability of 200 cycles. These modified LMO type adsorbents may be as competitive as some of the commercially available adsorbents used in DLE for Li recovery from sedimentary brines.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-413235

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