| 摘要: | 都市垃圾焚化飛灰主要成分有可溶性鹽類(K2O、Na2O)和SiO2、Al2O3、CaO等，以及高含量重金屬，通常認定為有害廢棄物。由於可溶性鹽類會對後續再利用上有安全的疑慮，而水洗程序是有效預處理方法之一，同時也將大量的重金屬一併洗除。坡縷石是一種多孔性的天然黏土礦物，具有價格低廉和高吸附量等優點，吸附焚化飛灰水洗液，其總重金屬去除效果極佳；再配合機械化學研磨， TCLP重金屬溶出顯著減少。
本研究分為兩組實驗，首先都是將原飛灰經過液固比5一次水洗。再依照水洗灰及活化後之坡縷石重量比10 : 0至10 : 7摻配比，並以液固比9進行濕式研磨穩定處理。其中第一組水洗係用純水，而第二組是將第一組的研磨後的分離液回用於水洗，探討研磨液迴流的可行性。
研究結果顯示，水洗灰和活化後之坡縷石混合研磨後，第二組實驗在研磨程序中各個配比重金屬溶出皆有下降之趨勢且比第一組實驗下降更多，其中又以重金屬鉛最為明顯。說明簡化水洗次數為一次且在經研磨過後，各配比研磨灰中重金屬皆具良好穩定效果，且研磨液回用並不會干擾重金屬穩定機制。經XRD晶相分析研磨灰發現有Ca4(Ca6(OH)1.2O0.5Cl0.32) (SiO4)2(SO4)2(Si0.5S0.5O4)2結晶產生，判斷係重金屬穩定之原因。水洗灰與活化後坡縷石摻配比10 : 3即能使重金屬(Cd、Cu、Pb、Zn與Cr)TCLP溶出分別降低達到0 % ~ 7.42 %，顯示此操作具有良好的穩定效果。
The components of municipal solid waste incinerator (MSWI) fly ash include SiO2, Al2O3, CaO, soluble salts and high concentration of heavy metals, usually be categorized as hazardous waste. The soluble salts will be the interference during the recovery, while washing is an effective pretreatment operation, which can also remove a lot of heavy metals. Polygorskite is a porous natural clay mineral, with low cost and high adsorption ability, which can decrease the heavy metals in the wastewater of MSWI fly ash washing effectively, followed by the mechanical chemical stabilization, TCLP concentration of heavy metals reduced dramatically.
This study was divided into two tests, both of then proceeded the wet milling stabilization with the combination of washed ash and activated polygorskite with ratio 10:0 to 10:7 (w/w), and liquid/solid ratio of 9; nevertheless, the washing of fly ash of test I used pure water, while test II recovered the separated liquid after milling operation of test I, to wash the fly ash.
The results showed that, after milling, the TCLP of heavy metals decreased evidently in the test II, compared to test I, especially for Pb; it showed the washing operation only once is enough, and the reuse of the separated liquid from the milling stabilization will not interfere the stabilization effect of heavy metals. The XRD analysis of milling stabilized sample found the crystal of Ca4(Ca6(OH)1.2O0.5Cl0.32)(SiO4)2 (SO4)2(Si0.5S0.5O4)2 produced, that might be the mechanism of heavy metal stabilization. Washed ash and activated polygorskite blending ratio 10:3 can make the dissolution of TCLP heavy metals (Cd, Cu, Pb, and Zn and Cr) decreased to 0 - 7.42 %, it showed a perfect stabilizing effect. |
