title: Recycling steel-manufacturing slag and harbor sediment into construction materials.
abstract: Mixtures consisting of harbor sediment and slag waste from steel industry containing toxic components are fired to produce non-hazardous construction materials. The fired pellets become lighter as firing temperature increases. At a sintering temperature of ≦1050°C, the fired pellets are in a form of brick-like product, while at 1100°C, they become lightweight aggregates. Calcium silicate, kyanite, and cristobalite are newly formed in the pellets after firing, demonstrating that calcium oxide acts as a flux component and chemically reacted with Si- and/or Al-containing components to promote sintering. Dioxin/furan content present in the pure slag is 0.003ng I-TEQg(-1) and, for the fired pellet consisting of slag and sediment, the content appears to be destructed and diminishes to 0.0003ng I-TEQg(-1) after 950°C-firing; while it is 0.002ng I-TEQg(-1) after firing at 1100°C, suggesting that dioxins/furans in the 950°C-fired pellets have a greater chance to escape to atmosphere due to a slower sintering reaction and/or that construction of dioxins/furans from molten chloride salts co-exists with their destruction. Multiple toxicity characteristic leaching procedure extracts Cu, Cr, Zn, Se, Cd, Pb, Ba, As, and Hg from all fired products at negligible levels.
authors.affiliation: Department of Environmental Science and Engineering, Tunghai University, Taichung City 407, Taiwan. Electronic address: yulin@thu.edu.tw.
authors.forename: Yu-Ling
authors.initials: YL
authors.lastname: Wei
authors.affiliation: Department of Environmental Science and Engineering, Tunghai University, Taichung City 407, Taiwan.
authors.forename: Chang-Yuan
authors.initials: CY
authors.lastname: Lin
authors.affiliation: Department of Environmental Science and Engineering, Tunghai University, Taichung City 407, Taiwan.
authors.forename: Shao-Hsiang
authors.initials: SH
authors.lastname: Cheng
authors.affiliation: Department of Environmental Engineering, National Cheng-Kung University, Tainan City 701, Taiwan.
authors.forename: H Paul
authors.initials: HP
authors.lastname: Wang
mesh_terms: D001151:Arsenic / Q000032:analysis; D003252:Construction Materials; D004147:Dioxins / Q000032:analysis; D004785:Environmental Pollutants / Q000032:analysis*; D005663:Furans / Q000032:analysis; D019015:Geologic Sediments / Q000032:analysis; D006358:Hot Temperature; D007220:Industrial Waste / Q000032:analysis; D008670:Metals / Q000032:analysis; D059027:Recycling; D013232:Steel; D018505:Waste Management / Q000379:methods*
chemical_list: D004147:Dioxins; D004785:Environmental Pollutants; D005663:Furans; D007220:Industrial Waste; D008670:Metals; D013232:Steel; D001151:Arsenic
keywords: Calcium silicate; Construction material; Lightweight aggregate; Sediment; Slag