Extraction of alumina from pulverised fly ash: Hwange power station

The authors describe experimental work done to establish the feasibility of extracting aluminum from pulverized fly ash (PFA) produced at the Hwange thermal power station in Zimbabwe. The results show that Al can be extracted in either acid or alkaline media. In acid, iron is co-dissolved, necessitating a subsequent separation stage. In alkaline solution only Al is extracted to yield 55% recovery as compared with 30% recovery in the acid system. The dissolution of Al is time/concentration dependent.