Hygroscopicity-driven spontaneous sustainable direct lithium extraction

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Current lithium extraction methods are energy, chemical, and water-intensive due to non-spontaneous separation processes.
• There is a critical need for sustainable and efficient lithium extraction techniques to meet growing demand.

Purpose of the Study:

• To develop a spontaneous, hygroscopicity-driven direct lithium extraction method.
• To leverage the deliquescent behavior of lithium chloride hydrate (LHT) for lithium enrichment from solid deposits.
• To minimize environmental impact by reducing energy, chemical, and freshwater consumption.

Main Methods:

• Utilized controlled relative humidities (12-30% RH) to induce selective water adsorption by crystalline LHT.
• Exploited phase-selective deliquescence for rapid solid-liquid separation without external water, reagents, or heating.
• Optimized humidity and moisture flux for efficient lithium recovery and concentration.

Main Results:

• Achieved rapid lithium recovery up to 96% with concentrations reaching 97,000 ppm.
• Demonstrated selective lithium enrichment, leaving co-occurring salts in the solid phase.
• Validated method robustness across various mixtures and actual mining slag samples under diverse conditions.

Conclusions:

• The hygroscopicity-driven method offers a sustainable, low-impact alternative for lithium extraction.
• This ambient-temperature, modular process minimizes resource consumption and enhances mining waste valorization.
• The technique shows competitive performance and broad resource tolerance, with significantly reduced extraction times.