A study comparing conventional heating and microwave assistance heating to recover metals from Municipal Solid Waste using microwave-assisted leaching technique

Abstract

This study investigates and compares microwave heating radiation with conventional heating. Incinerated Municipal Solid Waste (IMSW) bottom ash (BA) and fly ash (FA) was utilized to to recover various metals including Co, Cr, Cu, Fe, Mn, Zn,Pb, Al, Cd, Ba, Mg and V using various acidleaching agents i.e. HCl, HNO3 and H3PO4were utilized and several parameter were altered in order to determine the most effective conditions. The current study concluded that microwave assisted leaching method is effective to recover most of the metals. In addtion, metals from MSW-BA were much easier to recover in contrast with MSW-FA. 71% of Co, 75.69% of Cr, 56.19% of Cd, 35.23% of Ba and 30.2% of Pbusing 2M of HCland 3M of H3PO4. While 1.48% of Cr, 0.93% of Fe, 1.19% of Mn, and 1.18% of Al were extracting using HCL and H3PO4from MSW-FA. It was also confirmed that higher power and longer contact time had a positive effect on metal recovery. From cost analysis point of view,microwave assisted leaching was fraction of the cost for conventional heating making this method comparatively sustainable, energy efficient and safe.