| 摘要: | 都市垃圾焚化飛灰的性質複雜，其中重金屬多數超過TCLP溶出標準，所以多半採取固化處理，但仍有再溶出之虞，因此燒結是未來取代固化較好的替代方式。為了促進燒結體的重金屬穩定及降低燒結過程消耗的龐大能量，所以嘗試透過穩定劑的添加以及研磨，降低表面能量，改變焚化飛灰的結構特性並穩定其中的重金屬且提升燒結後的試體強度，以達到燒結資源化之效果。
本研究使用行星式球磨機，用高能濕式球磨的方式搭配穩定劑的添加並以氫氟酸總量消化，來了解重金屬在不同溫度的逸散率變化。並以粒徑分析儀、X-ray粉末繞射儀、掃描式電子顯微鏡等儀器，分析粉體研磨前後之性質差異與變化，以利於粉體後續之使用。
研究結果發現，研磨飛灰的重金屬溶出濃度低於法規標準。而以30％Al2O3取代水萃灰搭配以0.8M磷酸共同球磨，對於含量比較大的重金屬Zn跟Pb來說，在800℃以及1000℃時，對於重金屬Zn能有效的控制其逸散率在20％-30％之間，且在1200℃時，也能將其逸散率控制至41％。對於重金屬Pb的穩定效果上，在800℃時能將逸散率控制在14%左右，而在1000℃及1200℃的逸散率則是控制在22%左右，具有不錯的控制效果。而在強度上，也隨著溫度的提升強度逐漸增加，在1200℃時最高可達343 kg/cm2。
Since municipal solid waste incinerator (MSWI) fly ash contains a lot of heavy metals, which exceed the regulatory limits of hazardous waste usually, and the disposal of fly ash has presented a significant problem. Consequently, the stabilizing and recovering of MSWI fly ash is the majority trend, and sintering is a potentially technology in the future.
In the study, the characteristics of heavy metals volatilities of MSWI fly ash handled by water-extraction and then high energy ball milling with different stabilizers were investigated. The particle size analyzer, X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to exam the properties after milling. The hydrofluoric acid digestion was applied to evaluate the heavy metals volatilities of the ashes.
The results showed that, the addition of 30% Al2O3 with 0.8 M phosphoric acid ball milling, the volatility of Zn and Pb could be controlled within 20-30% in the sintering temperature of 800 and 1,000 oC, which can also control the volatility in 41% and 22%at 1200 oC relatively. The compression strength of regenerated aggregate was increased with the elevation of temperature gradually, reached 344 kg/cm2 at 1,200 oC, which reached the criteria of constructional aggregate.
Key words: MSWI fly ash, high energy ball milling, heavy metals, stabilization, sintering, regenerated aggregate. |
