chapter  7
16 Pages

Stabilization of Cadmium in Waste Incineration Residues by Aluminum/Iron-Rich Materials

Toxic metals enriched in the incineration residues of municipal solid waste (MSW) and sewage sludge are a substantial threat to ecosystems and human health. One example is cadmium, a toxic metal reported at concentrations ranging from 10 to 2100 mg/kg in y ash. Various sorbents (e.g., bauxite, alumina, and calcium oxide) are usually injected into thermal treatment processes to immobilize toxic metals. However, this method has certain disadvantages including the agglomeration of sorbents, the clogging of sorption sites, and the need for additional ash stabilization. Solidication/stabilization (S/S) technologies are an alternative which aim to use physical and/or chemical mechanisms to prevent metal leaching from waste incineration residues. Common S/S technologies use sorption or cementation to immobilize metals but may not reliably control metal leaching in a variety of acidic environments. The development of a novel, economical, and reliable technology to stabilize toxic metals, such as cadmium, in waste incineration residues is a timely and important need. Gamma-alumina (γ-Al2O3) and hematite (α-Fe2O3) are common, low-cost

Abstract .......................................................................................................................................... 239 7.1 Introduction ..........................................................................................................................240