Highly Efficient Lithium Recovery from Pre-Synthesized Chlorine-Ion-Intercalated LiAl-Layered Double Hydroxides via a Mild Solution Chemistry Process

Abstract

Lithium extraction from salt lake brine is critical for satisfying the increasing demand of a variety of lithium products. We report lithium recovery from pre-synthesized LiAl-layered double hydroxides (LDHs) via a mild solution reaction. Lithium ions were released from solid LiAl-LDHs to obtain a lithium-bearing solution. The LiAl-LDHs phase was gradually transformed into a predominantly Al(OH)3 phase with lithium recovery to the aqueous solution. The lithium recovery percentage and the concentration of the lithium-bearing solution were dependent on the crystallinity of LiAl-LDHs, the initial concentration of the LiAl-LDHs-1 slurry, the reaction temperature, and the reaction time. Under optimized conditions, the lithium recovery reached 86.2% and the Li+ concentration in the filtrate is 141.6 mg/L. Interestingly, no aluminum ions were detected in the filtrate after solid–liquid separation with high crystallinity LiAl-LDHs, which indicated the complete separation of lithium and aluminum in the liquid and solid phases, respectively. The 27Al NMR spectra of the solid products indicate that lithium recovery from the lattice vacancies of LiAl-LDHs affects the AlO6 coordination in an octahedral configuration of the ordered Al(OH)3 phase. The XPS O 1s spectra show that the Oad peak intensity increased and the OL peak intensity decreased with the increasing lithium recovery, which indicated that the Al-OH bond was gradually formed and the metal–oxygen–metal bond was broken.

Recent Advances in the Lithium Recovery from Water Resources: From Passive to Electrochemical Methods

“…[116] A similar idea was investigated by Xiang and co-workers first to remove Mg from brines with a high Mg:Li ratio and then to recover lithium directly from the brine through the nucleation and successive crystallization of LDHs. [117,118] In the first case AlCl 3 hexahydrate was added to the brine solution and was mixed with an alkaline solution in a colloid mill in order to start the nucleation process. The slurry was then transferred into a crystallization reactor and afterwards was filtered, washed, and dried to perform the solid-liquid separation.…”

“…Reproduced under the terms of the CC‐BY license. [ 118 ] Copyright 2019, The Authors, published by MDPI.…”

“…The LiAl-LDHs were then dispersed in deionized Reproduced under the terms of the CC-BY license. [118] Copyright 2019, The Authors, published by MDPI. [47] Copyright 2016, Elsevier.…”

“…Figure 5. a) Front view and b) top view of LDHs.Reproduced under the terms of the CC-BY license [118]. Copyright 2019, The Authors, published by MDPI.…”

Highly Efficient Lithium Extraction from Brine with a High Sodium Content by Adsorption-Coupled Electrochemical Technology

“…In our previous work, based on the lattice selectivity principle of layered double hydroxides (LDHs), a reaction-coupled separation technology was proposed for magnesium and lithium separation using MgAl-LDHs. The magnesium ions are selectively reacted to form solid MgAl-LDHs, whereas lithium ions cannot enter LDHs and are kept in the solution, which makes Mg/Li separation highly efficient. − However, a large amount of sodium ions is introduced after separating magnesium from lithium ions to form brine with a high sodium/lithium ratio. The monovalent feature and similar chemical properties of Na + and Li + make lithium extraction difficult from such brine.…”