基於「灰渣熔融」與「固化掩埋」終非垃圾焚化飛灰的最佳處理方式,甚至於難於符合「零廢棄」目標,開發一種新的低耗能低碳排放的飛灰資源化處理技術,使飛灰的再利用能符合綠色製程的「永續產品」,因此本研究承昔已有的成果基礎,將焚化飛灰與反應灰以1:1等比例混和,再利用直接加熱式酸解法、鹽析與中和等處理飛灰的有害性,在實驗設計與條件選擇下(改變加溫、酸解時間等),再以原子火焰吸收光譜儀測其萃取液中重金屬含量,使其皆合乎法規標準,期能同時削減飛灰中重金屬(以鉛為主),並同時控制飛灰中氯離子含量,降低飛灰(含反應生成灰)的有害性,使其無害化。 本研究可獲知焚化飛灰有害物質及氯離子含量之削減成效如下列重要結論: 1. 利用直接加熱式酸解及鹽析中和處理後,飛灰的主要化學性質發生了明顯改變,如氧化矽由23.21wt%降為20.38wt%,氧化鐵由2.05wt%降為0.74wt%,氧化鋁由4.70wt%降為1.86wt%,氧化鈣由25.95wt%降為8.34wt%,而這些物質極有可能形成與原氧化物不同的氫氧化物,或流失至酸液中。 2. 由相關實驗結果發現,Pb-TCLP削減成效約在63%~74%之間,氯全含量削減率約在15%~45%之間,若原飛灰(混合物)之TCLP值在控制40mg/L以內則可處理至法規要求5mg/L以下。
MSWI fly ash reutilitation is an issue of concern in the world. Because landfill disposal or thermal malting treatment does not meeting the reguirement of low GHG and energy-saving. The thermal degradation with salting precipitation studied in this work will be a promising technology to reduce Pb-metal and chloride in the MSWI fly ash. According to this study, it shows that the reduction of hazardous substances from Fly ash and the content of Chlorine : 1. After direct heating of the acid solution and salting processing, main chemical properties of fly ash has been significantly changed, such as SiO2 by 23.21wt % reduced 20.38 wt % , Fe2O3from 2.05wt % to 0.74wt % , Al2O3 from 4.70wt % to 1.86wt % , CaO from 25.95wt % to 8.34wt % , this substances probably formation the other hydroxide or loss in acid. 2. Found by experimental results, Pb-TCLP Reduction effectiveness between 63%~74%, the content of Chlorine Reduction effectiveness between 15%~45%, If TCLP value of the original fly ash under controlled 40mg / L, it can deal with regulation states 5mg / L