Beneficiation of lithium materials from pegmatite ores in rukungiri for energy storage applications

Abstract

Lithium, the new gold! Over the past decades, several lithium-based energy storage systems have been studied by various scholars due to the increased demand for this engineering material in the energy sector given its unique properties of high capacitance, energy density, high stability at elevated temperatures etc., supported by discovery of several lithium deposits around the world. This has created a thread of reliable and strong energy storage systems both small and large hence supporting the technological transition in several sectors including the transport industry worldwide. In this study, lithium materials beneficiated and extracted from local pegmatite ore in Rukungiri by leaching and sulfuric acid method respectively and meant for energy storage were investigated for electrochemical properties. Results showed that the pegmatite ore had a UCS of 69MPa, trace lithium content of 0.1ppm and an elemental composition of spodumene with high possibility of crushing for nanoscale disintegration of existing materials. The optimization of the sulfuric acid method realized a 53% lithium recovery at a grade of 54ppm while the non-charged lithium materials exhibited capacitance of 502µF, specific capacitance 13.5mF/g, and energy density (1.74mWh) together with power density per mass of 50W/g. The project was financially viable with NPV, IRR, PI and payback periods all revealing positive results. In conclusion, the Nyabushenyi lithium deposit has trace lithium that can be upgraded given advanced beneficiation techniques yet suitable for hybrid and electric double-layer capacitors energy storage systems that require high charge-discharge frequencies and higher power densities per mass as opposed to the primary energy systems like LIBs that require higher energy densities.