|About this Abstract
||Part C-3: Processing of Critical Metals
||Revisiting the Traditional Process of Spodumene Conversion and Impact on Lithium Extraction
||Colin Dessemond, Francis Lajoie-Leroux, Gervais Soucy, Nicolas Laroche, Jean-François Magnan
|On-Site Speaker (Planned)
Since the middle of the twentieth century, the traditional process has been dominating the production of lithium compounds from spodumene ores to sustain the ever-growing lithium market, both due to an economic viability and the need for technical grade (99.5 % purity) product. This process includes thermal conversion of spodumene, acid roasting of converted spodumene and lithium leaching. However, this process has not been challenged since and very few studies tried to explain the limitation of 90 % to 95 % lithium yield extraction or optimize the thermal treatment of spodumene ores. Here, spodumene conversion and lithium extraction were carried out into a rotary kiln using a 2 mm to 2 cm spodumene concentrate instead of a micrometric one using traditional conditions such as 1050°C, 30 min conversion treatment or 250°C, 30 min, 30 % sulphuric acid excess lithium extraction treatment. X-Ray Diffraction analyses were performed on the converted material to determine the rate of conversion of the concentrate by Rietveld analysis. It was observed that the α-spodumene particles fractured and divided during the thermal treatment while the impurity particles were not affected. A sifting was performed on the converted concentrate and it was determined that 65 % of the initial mass became finer than 180 µm. the sifting size was fixed at 180 µm because it is the average size of a flotation spodumene concentrate. X-Ray diffraction analyses and lithium content measurement were performed on both fractions and it was determined that the coarser fraction contained most of the impurities and that the finer fraction had a very high lithium content of 3.24 wt%. Lithium extractions were performed on both fractions separately and it was determined that while the coarser fraction’s lithium yield was only of 61 % the finer fraction’s lithium yield went up to 99 % without any additional treatment. These observations may open more economical ways for the traditional process by potentially bypassing two third of costly and energy demanding steps such as grinding or flotation.
||Planned: At-meeting proceedings