Alternative techniques for extracting alumina from coal fly ash

► Acetylacetone can extract up to 17.9% aluminium and sulphuric acid up to 23.5%. ► Aluminium extractions represent 64% and 85% from CFA amorphous phase respectively. ► Flow rate and temperature promote alumina dissolution in the gas-phase technique. ► Temperature and time promote alumina dissolution in the acid leaching method. ► Unreacted acetylacetone from the acetylacetone and CFA reaction is recyclable.