Recovery of rare earth elements and Yttrium from Indonesia coal fly ash using sulphuric acid leaching

Abstract

Rare Earth Element plus Yttrium (REY) is an essential element in the modern industry. Due to its limited supply, REY recovery from alternative sources is needed. Coal fly ash is one of the candidates of REY sources. Coal fly ash taken from the pulverized coal power plant in West Java was used as a raw material in this research. A sequential process of alkaline digestion and acidic leaching was applied for enriching and recovering REY from this coal fly ash. The enriching step using alkaline digestion produced desilicated residue with higher REY concentration than the raw coal fly ash. The sulfuric acid solvent was used for leaching the desilicated residue in this work to investigate its effect on REY recovery. The highest REY recovery obtained in this work was 75.25% which recovery process condition using 1 M H2SO4 concentration, liquid to solid (L/S) ratio of 25 (mL/g) and 30 minutes leaching time.