Hydrometallurgical Recovery of Zinc from Municipal Solid Waste Incineration Fly Ash

Abstract

The recovery of heavy metals from municipal solid waste incinerated fly ash (MSW-IFA) before its final disposal is highly desirable for sustainable waste management and resource recovery. Recycling of zinc via leaching-solvent extraction techniques has been studied, therefore yielding > 90% efficiency of zinc dissolution at a H2SO4 concentration of 1.5 mol/L, a temperature of 90 °C, a S/L ratio of 150 g/L, a time of 2 h, and a stirring speed of 300 rpm. Further, zinc was efficiently extracted using 0.6 mol/L D2EHPA at an equilibrium pH of 2.0 and an organic-to-aqueous phase ratio of 1. Finally, the highly pure zinc solution could be quantitatively stripped in a solution containing 1.5 mol/L H2SO4. This could lead to a circular economy of zinc with MSW-IFA as a possible secondary source.