Reductive thermal plasma conversion of a spodumene concentrate and impact on lithium extraction

Abstract

The conversion of α-spodumene was performed using two different CO2/CH4 thermal reductive plasma reactors. Using one configuration, particle size was proven to have a major role in lithium extraction. Lithium extraction efficiency decreases if the particles are too large. The third phase γ-spodumene is less reactive than β-spodumene and has a negative effect on lithium extraction. The other configuration showed that thermal plasmas were able to perform spodumene conversion with results close to that of traditional heating methods, electrical heating or gas burners. Thermal plasmas were proven to decrepitate coarse particles into micrometric particles with a lithium content increase in lower sized fractions. The lithium extraction was proven to be possible on plasma converted samples with lithium extraction efficiencies similar to that of classical heating methods for the lower sized fractions. This means that thermal plasmas could be used to replace CO2 and NOx emitting heating methods such as gas burners in spodumene conversion with similar results while consuming harmful gases instead of producing them, reducing the environmental impact of the process.