Production of lightweight aggregates from mining residues, heavy metal sludge, and incinerator fly ash.
In this study, artificial lightweight aggregate (LWA) manufactured from recycled resources was investigated. Residues from mining, fly ash from an incinerator and heavy metal sludge from an electronic waste water plant were mixed into raw aggregate pellets and fed into a tunnel kiln to be sintered and finally cooled rapidly. Various feeding and sintering temperatures were employed to examine their impact on the extent of vitrification on the aggregate surface. Microstructural analysis and toxicity characteristic leaching procedure (TCLP) were also performed. The results show that the optimum condition of LWA fabrication is sintering at 1150 degrees C for 15 min with raw aggregate pellets fed at 750 degrees C. The rapidly vitrified surface envelops the gas produced with the increase in internal temperature and cooling by spraying water prevents the aggregates from binding together, thus forming LWA with specific gravity of 0.6. LWA produced by sintering in tunnel kiln shows good vitrified surface, low water absorption rate below 5%, and low cylindrical compressive strength of 4.3 MPa. In addition, only trace amounts of heavy metals were detected, making the LWA non-hazardous for construction use.
Huang
Su-Chen
SC
Department of Atomic Science, National Tsing Hua University, 101, Sec. 2, Kuang Fu Road, Hsinchu 300, Taiwan, ROC.
Chang
Fang-Chih
FC
Lo
Shang-Lien
SL
Lee
Ming-Yu
MY
Wang
Chu-Fang
CF
Lin
Jyh-Dong
JD
D000538:Aluminum Silicates; D001546:Bentonite; D002244:Carbon; D000077215:Clay; D060729:Coal Ash; D003247:Conservation of Natural Resources; D003252:Construction Materials; D004581:Electronics; D006358:Hot Temperature; D017745:Incineration; D007220:Industrial Waste; D019216:Metals, Heavy / Q000032:analysis; D008906:Mining; D052638:Particulate Matter; D012722:Sewage; D018505:Waste Management / Q000379:methods
D000538:Aluminum Silicates; D060729:Coal Ash; D007220:Industrial Waste; D019216:Metals, Heavy; D052638:Particulate Matter; D012722:Sewage; D001546:Bentonite; D002244:Carbon; D000077215:Clay