Improving Lithium Extraction from Claystone: Maximizing Efficiency and Sustainability with Integrated Beneficiation and Sulfuric Acid Leaching
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Authors
Arthur, Sabinus Essel
Issue Date
2025
Type
Thesis
Language
en_US
Keywords
Attrition , Chemical Dispersion , Gravity Concentration , Leaching , Life Cycle Assessment , Lithium
Alternative Title
Abstract
The fast paced electric vehicle (EV) adoption and the expansion of renewable energy storage systems has led to a resurgence in demand for Li, with domestic demand outpacing its production by more than 25% since 2019. Sedimentary claystones in Nevada are a new type of resource for lithium. The current industrial approach to extract lithium from these resources mostly employs direct sulfuric acid leaching and does not involve beneficiation to remove gangue minerals such as carbonates. This not only results in the excessive use of sulfuric acid but the generation of carbon dioxide as a byproduct of the leaching reaction. To improve the economics and sustainability of lithium extraction, it is desirable to incorporate a beneficiation step prior to the hydrometallurgical operation. In this study, a smectitic claystone was beneficiated using a previously developed method and subsequently leached using sulfuric acid. Response surface methodology (RSM) was employed to study the effects of acid concentration, leaching temperature and time, and solid-liquid ratio on the lithium extraction from the beneficiated claystone. The results showed that the beneficiation was able to recover 91% of lithium while rejecting 86% of calcium. The beneficiated claystone yielded a high lithium recovery of 89.18% after leaching at optimum conditions of 1.31 M acid concentration, leaching temperature of 80 °C, leaching time of 1.93 hours, and 26% solid-liquid ratio generated by response surface methodology (RSM). Compared with the industrial approach, the leaching process incorporating the beneficiation stage reduces the acid consumption from 106 g/g lithium to 23 g/g lithium and the environmental impact expressed in terms CO2 emissions from 4.26E-01 kg CO2eq/g lithium to 1.51E-01 kg CO2eq /g lithium.