Physical and chemical characterization of El Kriymat boiler ash to optimize the leachability of some valuable elements

Abstract

Boiler ash is characterized by the presence of vast aggregates of both economic and strategic elements which reflect the importance for their recovering. A petroleum ash sample was collected from the boiler of El Kriymat steam electric station located in south Cairo, Egypt. Chemical analysis of this petroleum ash sample revealed that V and Ni are present as major elements while the minor elements are represented by Fe and S. Trace elements include Ti, Ca, K, Cl, Si, Ba, Zr, Y, Sr, As, Zn, Cr, Mn, Th and U. The present work aims to investigate the nature of this sample either mineralogically and chemically on the one hand, and the possibilities of extracting such valuable elements on the other.The obtained results revealed the possibility of saving both reagents and time, about 98% leaching efficiency upon the summation valuable metals fractions (0.05–1) amperes (A) by applying the optimum conditions 180 g/l H2SO4 acid, 6% MnO2 (solid/solid ratio) as oxidant agent, 80 °C temperatures, 6 h, 1/10 (S/L) ratio and -200 mesh grain sizes. While, 150 g/l H2SO4 acid at fixed the other parameters (6% of MnO2, 80 °C temperatures, 6 h, 1/10 (S/L) and -200 mesh grain size) upon totality fractions (1–3) amps was sufficient for dissolving more than 98% of the exciting valuable metals.