Hydrothermal solidification of municipal solid waste incineration bottom ash with slag addition.
Hydrothermal solidification of municipal solid waste incineration (MSWI) bottom ash has been carried out under saturated steam pressure (1.56 MPa) at 200 degrees C for up to 24 h by mixing quartz, slaked lime and water-cooled blast furnace slag (WBFS). The strength enhancement for the WBFS addition was best. The strength development was shown to be due mainly to tobermorite formation, and the tobermorite formation densified matrix, thus promoting the strength development. WBFS seemed to have a higher reactivity than the quartz during the initial hydrothermal process, which provided more silica available to harden the solidified specimens. However, a longer curing time (24 h) was favorable to the quartz dissolution for tobermorite formation, which in turn, enhanced the strength for quartz addition. Curing time affected the crystal morphology evolution, and the stubby plate of tobermorite seemed to result in a high strength enhancement in this study. Laboratory leaching tests were conducted to determine the amount of heavy metals dissolved from the final solidified specimens, and the leaching results showed that after hydrothermal processing the heavy metals dissolved from the solidified specimens were reduced effectively. As such, the hydrothermal processing may have a high potential for recycling/reusing MSWI ash on a large scale.
Jing
Zhenzi
Z
Key Laboratory of the Advanced Civil Engineering Materials, Ministration of Education, Tongji University, 1239 Siping Road, Shanghai 200092, China. zzjing@tongji.edu.cn
Ran
Xianqiang
X
Jin
Fangming
F
Ishida
Emile H
EH
D002244:Carbon / Q000737:chemistry*; D003247:Conservation of Natural Resources / Q000379:methods; D003252:Construction Materials; D004785:Environmental Pollutants / Q000032:analysis / Q000737:chemistry*; D017745:Incineration / Q000379:methods*; D008422:Materials Testing; D055595:Mechanical Phenomena; D019216:Metals, Heavy / Q000032:analysis
D004785:Environmental Pollutants; D019216:Metals, Heavy; D002244:Carbon