Recovery of gallium from coal fly ash

A study has been made on the extraction of gallium from coal fly ash. A process which includes acid leaching, impurity removal, foam extraction of gallium and its purification has been suggested. The relatively moderate conditions of temperature, acid strength and time should be chosen in acid leaching to obtain the most efficient extraction of gallium. The experiments showed that the major elements in fly ash, such as aluminum, iron, silicon and calcium, can be recovered efficiently via the proposed flowsheet and that secondary environmental pollution can be avoided.