以高溫熱熔融法處理淘洗焚化飛灰之研究

Treatment of elutriated incinerator fly ashes using a thermal melting process

陳怡如(Chen Yi-Ru)

指導教授 ： 黃國林 ； 郭益銘

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2018年)

https://doi.org/10.6346/THE.NPUST.ESE.032.2018.E02

摘要

本研究以去離子水洗滌出飛灰中高溶解性之物質，探討不同液固比淘洗後飛灰金屬總量，並求得最佳之淘洗配比。利用最佳淘洗過後飛灰之試程進行不同配比助熔劑添加量之熱熔融實驗，檢測熱熔融產物(熔渣)之金屬元素成分、外觀及毒性特性溶出試驗(TCLP)之金屬元素溶出情形，並輔以反應曲面法(RSM)進行參數試驗，藉以評估熔渣後續再利用之可行性。
實驗結果顯示，飛灰經由二次淘洗後，重金屬含量仍有逐漸減少之趨勢，且以液固比10:1為最佳淘洗配比。此淘洗程序可將大量之可溶解性物質洗出，而藉由淘洗次數增加亦可降低淘洗後飛灰與水溶液之重金屬含量。
利用淘洗過後飛灰進行熱熔融試驗所得熔渣，其主要元素為Si、Ca、Fe、Na及Al為主。將熔渣研磨混拌黏土添加劑、玻璃砂及水泥後，製成環保磚，其強度可符合C級磚(4 N/mm2)之需求，其毒性特性溶出值亦低於法令標準，顯示將之製成環保空心磚為具潛力之資源化再利用方式。

關鍵字

焚化飛灰 ； 淘洗 ； 高溫熱熔融法 ； 反應曲面法 ； 環保空心磚

並列摘要

In this study, deionized water was used to elutriate the high soluble components of fly ash at different liquid-solid ratios. The total metal amounts of elutriated fly ash specimens were analyzed to evaluate the best elutriating (liquid-solid) ratio. Then, the best elutriate fly ash specimen was used in thermal melting tests under different amounts of melting-aid additions. The melted products (slags) were examined for metal element compositions and appearances and by the Toxicity Characteristic Leaching Procedure (TCLP) to access the feasibility of subsequent reuse of slags. The parameter test was performed by the Reaction Surface Method (RSM).
The results show that the heavy metal content of doubly elutriated fly ash specimen still gradually decreased, and the best elutriating (liquid-solid) ratio was 10:1. This elutriating process could wash out a large amount of soluble species from fly ash. Moreover, increasing elutriating time reduced the heavy metal content of elutriated fly ash and that in the elutriating solution after elutriation.
Accordingly, the elutriated fly ash was used for thermal melting tests. It was found that the main elements of the slag obtained from the melted fly ash were mainly Si, Ca, Fe, Na, and Al. The pulverized slag was mixed with clay, glassy sand, and cement to make environmentally hollow bricks. The strength of hollow bricks met the standard of C-level brick (4 N/mm2). The metal leaching data also fulfilled the regulatory standards of TCLP, revealing that to recycle the slags as hollow brick is a promising recycling way.

並列關鍵字

Incineration fly ash ； Elutriation ； Thermal melting ； Response Surface Methodology (RSM) ； Environmentally hollow brick

參考文獻

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