Sequential Leaching of Vanadium from Heavy Fuel Oil Fly Ash Generated from Saudi Arabia Thermal Power Plants

The leaching characteristics of vanadium (V), iron (Fe) and nickel (Ni) from fly ash (FA) waste of power station in Saudi Arabia were studied. The kinetics and thermodynamic characteristics of V leaching from FA using a series of leaching agents (H2O, NH4OH, HCl, H2SO4) were studied. The rate of leaching of V was fast; reached equilibrium in a short time and followed a first-order rate equation with an overall rate constant k of 0.076 min-1. The thermodynamic parameters of V leaching in different leaching agents were critically investigated. The negative values of ∆H and ∆G were interpreted as the exothermic and spontaneous reaction of V leaching onto the leaching solution. Sequential proposed scheme for V leaching is also included.