Optimal Mixture Designs for Heavy Metal Encapsulation in Municipal Solid Waste Incineration Fly Ash

Abstract

Mixing municipal solid waste incineration fly ash (MSWIFA) with industrial by-products such as ground granulated blast furnace slag (GGBFS) and ladle furnace slag (LFS) can lead to a hardened system which can encapsulate the heavy metals present in the MSWIFA. The objective of this study is to find optimal mixture designs to effectively encapsulate these heavy metals. The nature of the hydrates and the strength of the mixtures are studied to develop a sustainable and practical construction material incorporating MSWIFA. Heavy metals including Cr, Cu, Zn and Cd are safely encapsulated in several developed mixtures with leachate concentration below EPA drinking water limit. The encapsulation behavior is complex and depends on metal type, age of testing, and hydration products. In general, mixtures containing LFS have more aluminate hydrates, and show greater encapsulation capacity for most heavy metals. However, they also generally show significant Sb leaching. Mixtures which show satisfactory encapsulation for all ions and adequate strength development are identified. Three ideal mixtures, including one containing zero cement, are identified which satisfy both leaching and strength requirements.

Reuse of lead glass sludge in the fabrication of thermally insulating foamed glass with outstanding properties and high Pb-stabilization

“…The exposure of LGS to elevated temperature not only yields foamed materials with highly thermal insulating property but also strongly affects the reduction of free Pb within LGS. Several previously published works (Nikolić et al 2014 ; Wang et al 2020 ; Abdel-Gawwad et al 2020c ; Long et al 2021 ) proved that the Pb-leaching strongly influenced by the compaction and porosity of the hardened materials. The hardened material with the highest compressive strength and lowest porosity exhibits the highest efficiency in Pb-immobilization.…”

Sustainable Chromium Encapsulation: Alkali Activation Route

“…The cementification of heavy metals suffers from certain limitations due to the co-presence of anions, chief among them being chlorides, and the possible excess of water and/or organic and oily substances (Ebert and Kirkelund, 2022). In order to minimize such adverse effects on cement fresh paste or hardened properties, several admixtures of minerals: zeolites (Bagosi and Csetenyi 1999), bagasse ash (Tantawy et al, 2012), metakaolin (Lancellotti et al, 2015), slag (Zhang et al, 2017), fly ash based geopolymer (Kupwade-Patil et al, 2014;Wang et al, 2020) or macromolecules: latexes and acrylic polymers, naphthalene-and chitosan-derivatives have been proposed (Stampino et al, 2009).…”