Chemical and physical properties of plasma slags containing various amorphous volume fractions.
In this study, municipal solid waste incinerator fly ash was vitrified using a plasma torch. The fly ash contained rich Ca, causing a high basicity of 2.43. Pure quartz was used as an additive to adjust the basicity. BET surface area analysis, X-ray diffraction analysis, and a scanning electron microscope were used to examine the physical properties of slags. The chemical stability and the acid resistance of slags were evaluated using the toxicity characteristics leaching procedure and tests of acid bathing. The results indicate that the plasma torch effectively vitrified the fly ash. Anthropogenic metals with low boiling points, such as Cd, Pb, and Zn, were predominately vaporized into flue gas. Most of the metals with high boiling points, such as Cr, Cu, and Mn, remained in the slag. After the vitrification, hazardous metals were noticeably immobilized in all slags. However, the slags with higher amorphous volume fractions were more effective in metal immobilization and in resisting acid corrosion. This indicates that SiO(2) enhanced the formation of the glassy amorphous phase and improved the resistance of acid corrosion and the immobilization of hazardous metals.
Department of Safety Health and Environmental Engineering, Chung Hwa University of Medical Technology,Taiwan, Republic of China.
Yi-Ming
YM
Kuo
Chih-Ta
CT
Wang
Cheng-Hsien
CH
Tsai
Lin-Chi
LC
Wang
D000465:Algorithms; D002118:Calcium / Q000032:analysis; D002244:Carbon / Q000032:analysis*; D060729:Coal Ash; D003460:Crystallization; D015386:Hazardous Substances / Q000032:analysis; D017745:Incineration; D008670:Metals / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D052638:Particulate Matter / Q000032:analysis*; D011791:Quartz; D012037:Refuse Disposal / Q000379:methods*; D012995:Solubility; D013624:Taiwan; D014961:X-Ray Diffraction
D060729:Coal Ash; D015386:Hazardous Substances; D008670:Metals; D052638:Particulate Matter; D011791:Quartz; D002244:Carbon; D002118:Calcium