Lithium extraction from the mineral zinnwaldite: Part II: Lithium carbonate recovery by direct carbonation of sintered zinnwaldite concentrate. (15th August 2017)

• Record Type: Journal Article
• Authors: Martin, G.; Schneider, A.; Voigt, W.; Bertau, M.
• Is Part Of: Minerals engineering. Volume 110(2017)
• Page Start: 75
• Page End: 81
• Publication Date: 2017-08-15
• Subjects: Zinnwaldite -- Lithium -- Lithium carbonate -- Thermal treatment -- Supercritical carbon dioxide; Mines and mineral resources -- Periodicals; Ressources minérales -- Périodiques; Mines and mineral resources; Periodicals; Electronic journals; 622
• DOI: 10.1016/j.mineng.2017.04.009
• Languages: English
• ISSNs: 0892-6875

Abstract

Highlights: Process for production of Li2 CO3 from sintered zinnwaldite concentrate. Direct carbonation process enables Li mobilisation rates up to 75%. Efficient and gentle concentration of LiHCO3 containing solution by electrodialysis. Product purities of ≥99.0% due to high Li-selectivity of CO2 treatment. Abstract: Based on decomposition studies of zinnwaldite in Part I, a process for lithium carbonate production by supercritical carbon dioxide ( sc -CO2 ) treatment was developed and optimised to high lithium yields. Sintered and ground zinnwaldite concentrate was subjected to CO2 /water treatment at elevated pressure (100 bar) and moderate heating (230 °C). Mobilisation rates of over 70% were attained. The filtered lithium bicarbonate containing solution was concentrated by electrodialysis up to a lithium content of 8.5 g/L. Precipitation of lithium carbonate was achieved by CO2 elimination at 90–95 °C. A high selectivity of CO2 treatment for alkali metals, specifically for lithium, enables lithium carbonate product purities of ≥99.0% without additional rinsing.