都市垃圾焚化飛灰石材化之研究

Production of Synthetic Stone From Municipal Solid Waste Incineration Fly Ash.

周富源(Fu-Yuan Chou)

指導教授 ： 施信民

國立臺灣大學/工學院/化學工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.10290

摘要

都市垃圾焚化飛灰的再利用須克服飛灰中高含量的氯鹽以及重金屬溶出的問題。本研究探討以洗滌、燒結的方式克服前述問題而將飛灰製備成石材之可行性。於空氣污染防制設備收集的飛灰分別以去離子水、氫氧化鈉溶液(1-10wt.%)、磷酸溶液(1-10wt.%)洗滌(液固重量比７)，過濾、乾燥後，以5000psi的壓力造粒，再於900℃與1000℃下燒結1小時。
飛灰洗滌後，其氯鹽含量大幅降低。水洗灰與酸洗灰經高溫燒結後，重金屬的溶出量，以酸洗灰較小，但兩者皆不超過台灣溶出毒性事業廢棄物之溶出標準值，而鹼洗灰則否。飛灰以磷酸洗滌會產生磷酸鈣之膠體沈澱，而將重金屬穩定於燒結體中。酸洗灰燒結後，抗壓強度高於水洗灰與鹼洗灰，飛灰以5wt.%與10wt.%磷酸洗滌後之燒結體，長時間置放不會產生崩解的現象，而其抗壓強度(112-305 kgf/cm3)及Vickers硬度在（1.65~5.37GPa）與普通磚及大理石相當，可作為建材使用。

關鍵字

石材化 ； 飛灰

並列摘要

The utilization of municipal solid waste incinerator fly ash has to overcome the problems of high contents of chlorides and leaching of heavy metals. The feasibility of producing artificial aggregates from fly ash by a combined washing and sintering process, in which most alkali chlorides could be removed and heavy metals could be immobilized, has been studied. Fly ash, collected at the air pollution control units, was washed with deionized water, NaOH solutions (1-10 wt.%), and H3PO4 solutions (1-10wt.%), respectively, with a liquid/ solid weight ratio of 7. The dry washed samples were then pelletized with a pressure of 5000 psi. and were sintered at 900 ℃ and 1000 ℃ for 1 hour.
The chlorine content of fly ash was markedly reduced after washing. Leaching tests of fly ash treated by the combined process showed that the amounts of heavy metals dissolved were less than the standard values set for the hazardous industrial wastes in Taiwan, only for fly ash washed with deionized water or with phosphorous acid solutions. However, the immobilization of heavy metals was more pronounced in the later case. In that case, heavy metal ions were immobilized in the matrix of calcium phosphate gel, and subsequently were stabilized in the sintered cylinders. The compressive strengths of sintered cylinders were greater for fly ash washed with phosphorous acid solutions. When 5 wt% and 10 wt% phosphorous acid solutions were used, the sintered cylinders did not disintegrate for a long period of exposure in ambient air; their compressive strengths (112~305 kgf/cm3) and values of Vickers hardness (1.65~5.37GPa) were comparable to that of bricks and marble. Fly ash treated by washing with phosphorous acid solutions and subsequent sintering may be considered suitable to use as a constructive material.

並列關鍵字

Synthetic Stone ； Fly Ash

參考文獻

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