Aqueous Recovery of Zinc and Lead from Coal Fly Ashes of a Colombian Thermoelectric Plant

A hydrometallurgical treatment under ambient conditions was proposed in order to eliminate and recover the lead zinc contained a sample of thermal coal fly ash used produce energy. By using leaching solutions with conventional inorganic acids (HCl, HNO3, H2SO4), ferric chloride, sodium citrate, more than 90% approximately 40% were obtained. The most favorable set at 0,5 M, pH value 8 for citrate. Two stages necessary optimize metal recovery: first nitric acid extraction second one citrate lead. sulfur phases metals limited complete extraction.