Development of Value-added Lucent: Transparent Glass Using Hazardous MSWI Fly Ash

2. Department of Safety, Health and Environmental Engineering, National United University, Taiwan, ROC

Abstract: Municipal solid waste incineration (MSWI) fly ash (FA) containing hazardous metals (especially Pb and/or Cd), high water-soluble chloride (Cl–), and other complex constituents bring on a traditional treatment of solidification/stabilization (S/S) and landfill disposal in most countries. In this paper, a MSWI FA sampled from M Plant was studied for developing an innovative method of fabricating value-added lucent/transparent glass. The analysis of MSWI FA shows that TCLP-Pb was 36.0 mg/L exceeding regulatory limit (5.0 mg/L) and Cl– content was 32.84%. Composition analysis of MSWI FA illustrates that total chloride (ClT) of 35.39% was the largerest constituent and Cl–, occupying nearly 93%, is the majority of ClT. Other abundant constituents were Ca (25.17%), Na (7.07%), K (5.01%) and Pb (2.68%) etc., revealing the possibility of fabricating glass. Unfortunately, Fe content in FA was 0.6%, larger than 0.1%, which may display green color in glass. Pre-experiments of fabricating glass using MSWI FA, silica sand (SiO2) and flux (Na2CO3) concluded that 30%: 40%: 30% and 1,300°C firing temperature was the optimal fabrication condition but a green glass was also generated. Further efforts including pre-treating FA by magnetic removal of iron constituents and adding decolorizer (CaF2) were explored. Finally, a lucent/transparent glass fabricated by the combination of pre-treatment of FA and adding 10% of CaF2 was obtained. Further application of this simple and quick method, replacing the traditional S/S and landfill disposal, to fabricate value-added glass and achieve circular economy is highly expected.