title: Production of lightweight aggregates from mining residues, heavy metal sludge, and incinerator fly ash.
abstract: 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.
authors.affiliation: Department of Atomic Science, National Tsing Hua University, 101, Sec. 2, Kuang Fu Road, Hsinchu 300, Taiwan, ROC.
authors.forename: Su-Chen
authors.initials: SC
authors.lastname: Huang
authors.forename: Fang-Chih
authors.initials: FC
authors.lastname: Chang
authors.forename: Shang-Lien
authors.initials: SL
authors.lastname: Lo
authors.forename: Ming-Yu
authors.initials: MY
authors.lastname: Lee
authors.forename: Chu-Fang
authors.initials: CF
authors.lastname: Wang
authors.forename: Jyh-Dong
authors.initials: JD
authors.lastname: Lin
mesh_terms: 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
chemical_list: D000538:Aluminum Silicates; D060729:Coal Ash; D007220:Industrial Waste; D019216:Metals, Heavy; D052638:Particulate Matter; D012722:Sewage; D001546:Bentonite; D002244:Carbon; D000077215:Clay