The Effect of HNO3 Concentration Variations on the Recovery of REEs from Coal Fly Ash Through Hydrometallurgical Process

Abstract

In this study, coal fly ash was used as the primary material for analysis and extraction of REEs contained therein. Coal fly ash is a waste product from coal combustion, commonly used in the power generation sector, which is typically disposed of without furthering processing. Therefore, this study was conducted to utilize this waste, which contains a significant amount of REEs, for use in the metallurgy industry as strategic additives in material engineering. The rare earth metal recovery process involved leaching with strong acid HNO3 at concentrations of 0.6 M, 0.8 M, and 1 M. Analysis using the ICP-OES method on the three variations yielded very low dissolution of REEs. Characterization with XRD of the leaching results showed that the leaching process effectively mobilized and reformed REEs into various new crystalline phases.