| Abstract: | 電弧??鋼集塵灰顆?微細，其成份主要以鐵和鋅為主，重金屬成分則含鉛、鉻、銅、鎳、鎘等，經毒性溶出試驗(TCLP)結果顯示，大多?電弧爐?鋼集塵灰皆超出毒性溶出標準，屬於有害事業廢棄物。若使用電弧爐集塵灰廢棄物為原料製備成輕質骨材，可達到廢棄物資源化，減少天然資源開採的目標。 研究結果顯示，純電弧爐集塵灰無法燒製成輕質骨材，此乃由於試體表面上無法形成玻璃相。由於無法將重金屬包覆於玻璃相內，故其重金屬溶出試驗大多不符合法規標準；但是添加於水庫淤泥、廢棄玻璃粉與大理石粉經高溫燒結後，其重金屬溶出量皆符合TCLP法規標準。 水庫淤泥、廢棄玻璃與電弧爐集塵灰(重量比例：40/40/20)在1150℃與1200℃下燒製兩分鐘，其顆粒密度各為0.95 g/cm3與0.89 g/cm3，皆符合規範，亦達到工業節能之目標。 本實驗所有配比所燒製成之輕質骨材，其吸水率大部分合乎運用於營建工程實用可接受之規範( <12 % )。
EAF dust is very fine in particle size, and its primary compositions are iron and zinc. It contains toxic metals lead, chromium, copper, nickel, cadmium, and others. The toxicity characteristic leaching procedure (TCLP) test shows that EAF dust leaches toxic metals at levels exceeding legal standards. Therefore EAF dust is classified as hazardous industrial waste. If EAF dust waste is used as raw material for preparing lightweight aggregates at elevated temperatures, then not only the waste can be transformed into resources, but also the exploitation of natural resources be reduced. The results show that pure EAF dust is incapable of being turned into lightweight aggregates because the surface of sintered products don’t form glass phase. Further, because the toxic metals can’t be stabilized due to a lack of glass phase, most TCLP concentrations of toxic metals do not meet regulatory standards. However, mixed with sediment, waste glass powder, and marble powder, high-temperature sintering can lead to the results that all toxic metal TCLP concentrations conform to legal limit. For LWAs made from mix of sediment, EAF dust, and waste glass (weight ratio: 40/40/20) at 1150oC and 1200oC for two minutes, their respective particle densities are 0.95 g/cm3 and 0.89 g/cm3, both conforming to practical construction engineering requirement. In fact, such a short sintering time also achieves the goal of less energy demand. In addition, the lightweight aggregates made with all weight ratios in present study meet the requirement in water absorption from the aspects of practical construction engineering application (<12%). |
