Evaluation of leaching characteristic and kinetic study of lithium from lithium aluminum silicate glass-ceramics by NaOH

The behavior and mechanism of Li leaching from lithium aluminum silicate glass-ceramics which can be used as a secondary source of Li using aqueous NaOH solution was investigated. The Li leaching efficiency is increased with increasing concentration of NaOH, specific surface area, and reaction temperature. When leached under optimum conditions, 2 mol/L NaOH, 53 mu m particle undersize, 1:10 solid/liquid ratio, 250 r/min stirring speed, 100 degrees C reaction temperature, 12 hr, the Li leaching efficiency was approximately 70%. However, when the leaching experiment was performed for 48 hr, the concentration of Li+ ions contained in the leach liquor decreased from 1160 to 236 mg/L. To investigate the origin of this phenomenon, the obtained leach residue was analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. These analyses show that zeolite was formed around the lithium aluminum silicate glass-ceramics, which affected the leaching of by adsorbing Li+ ions. In addition, using the shrinking-core model and the Arrhenius equation, the leaching reaction with NaOH was found to depends on the chemical reaction of the two reactants, with a higher than 41.84 kJ/mol of the activation energy. (c) 2021 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

Automated summary

The study investigated the behavior and mechanism of Li leaching from lithium aluminum silicate glass-ceramics using aqueous NaOH solution. The efficiency of Li leaching was found to increase with higher NaOH concentration, specific surface area, and reaction temperature. However, prolonged leaching time may result in a decrease in Li leached due to the formation of zeolite around the glass-ceramics.