Lithium extraction from ß-LiAlSi2O6 structure by thermal reaction with Na2CO3

M. L. GRASSO; J. GONZÁLEZ; F.C. GENNARI

Antofagasta

Workshop; 7th International Workshop on Lithium, Industrial Minerals and Energy; 2020

CICITEM (Centro de Investigación Científica Aplicada a Soluciones Tecnológicas para la Región de Antofagasta)

Lithium is widely used to produce compounds for battery, aerospace, nuclear and pharmaceutical fields. The natural occurrence of this metal are brines and ores such as amblygonite (LiAl[OH,F]PO4), spodumene (LiAlSi2O6), petalite (LiAlSi4O10) and eucryptite (LiAlSiO4). Spodumene is an attractive lithium source due to its Li2O content (6-9wt%). The traditional methods to extract lithium from spodumene consist in lime roasting (CaO), chlorination (CaCl2, Cl2) or acid leaching (HF, H2SO4) [1]. In the application of extraction methods, it usually uses the reactive polymorph of the mineral, -spodumene. On the other hand, Chen et al. [2] reported a novel acid-free method to produce Li2CO3 using aqueous Na2CO3 and -spodumene. The method implies an autoclave process followed an aqueous leaching under CO2 flow to produce LiHCO3 and analcime phase (NaAlSi2O6). Then a precipitation stage allows recover a maximum of 94% Li2CO3. Recently, dos Santos et al. [3] described a solid-state process using a mixture of Na2CO3-NaCl with a maximum lithium conversion of 71% after 2 hours at 650ºC.In this work, we analyze the lithium removal from -LiAlSi2O6 structure using Na2CO3 as extracting agent. Solid state thermal reactivity between -LiAlSi2O6 and Na2CO3 was evaluated at different temperatures, avoiding the use of solvents. The investigation was complemented with a thermodynamic analysis.