焚化飛灰磷酸處理資源化技術開發

Production of aggregates from incinerator fly ash with phosphoric acid treatment.

容州谷(Chou-Ku Rong)

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(2008年)

https://doi.org/10.6342/NTU.2008.03165

摘要

垃圾焚化處理產生的飛灰含有高含量的氯鹽及微量的重金屬與毒性氯化有機物，屬於有害廢棄物。本研究探討焚化飛灰以水或磷酸溶液洗滌再經煅燒處理，以去除氯鹽和固定重金屬，製備低氯含量、重金屬安定的石材之可行性以及其最佳操作條件。本研究將於空氣污染防制設備收集的飛灰分別以去離子水和磷酸溶液(1wt%~10wt%)洗滌(液固重量比10)，經過濾、乾燥後，以5000psi的壓力造粒，再於900℃與1000℃下煅燒1小時。
飛灰經水洗或酸洗可以顯著降低固體的氯含量。毒性溶出試驗的結果顯示，經過處理的飛灰，其重金屬溶出量皆遠低於法規限值。飛灰經水洗或酸洗或煅燒可以顯著降低鉛的溶出量，但只些微降低Cr的溶出量，而酸洗會增加Cd的溶出量，酸洗並燒結會增加Cu的溶出量。水洗灰與酸洗灰(磷酸濃度≧5wt%)經造粒與高溫燒結後，其初期抗壓強度(112-760Kgf/cm2)與普通磚及大理石相當，但燒結體長時間置放會風化崩解。

關鍵字

焚化飛灰 ； 廢棄物資源化 ； 磷酸 ； 氯鹽

並列摘要

Fly ash generated from incinerator contains high contents of alkali chlorides and trace amounts of heavy metals and toxic organics, and it belongs to hazardous wastes. This work studies the feasibility of producing artificial aggregates from fly ash by using a process in which the raw fly ash is washed by deionized water or phosphoric acid and then calcined at high temperatures to remove the alkali chlorides and stabilize the heavy metals.
Fly ash, collected from the air pollution control unit, was washed with deionized water and H3PO4 solutions(1wt%~10wt%), respectively, with a liquid/ solid weight ratio of 10. The dry washed samples were pelletized with a pressure of 5000psi, and the pellets were sintered at 900℃ and 1000℃ for 1 hour.
After washing the fly ash, the chlorine content of the fly ash decreased markedly. Leaching tests for the fly ash treated by washing and/or sintering showed that the amounts of heavy metals leached were far less than the regulatory limits in Taiwan. The amount of Pb leached decreased markedly after the fly ash was treated, but the amounts of Cr leached decreased only a little. The amount of of Cd leached increased if the fly ash was washed with H3PO4 solutions, and that of Cu leached increased if the acid-washed ash was sintered.
The sintered cylinders of the fly ash washed with deionized water or with 5 and 10 wt%H3PO4 solutions had initial compressive strengths (112-760Kgf/cm2) comparable to those of bricks and marble. However, the sintered cylinders disintegrated due to weathering.

並列關鍵字

Municipal solid waste incinerator fly ash ； Waste recycling ； Phosphoric acid ； Chloride

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