| 摘要: | 都市垃圾焚化飛灰是一種性質複雜且不易處理之有害廢棄物，因此焚化飛灰的回收再利用已成為未來的趨勢，其中將飛灰取代部分水泥製成環保水泥是最具有資源化的潛力，但是飛灰中有氯鹽、重金屬及硫酸鹽等問題，因此處理飛灰中有害物質為再利用前的首要考量。
本研究利用水萃、研磨、磷酸穩定搭配研磨等程序處理焚化飛灰。將處理後飛灰取代部分水泥，製成水泥漿體，以強度及健度等測試來觀察經過處理之後的粉體對於取代水泥後的影響，再以XRD及SEM來觀察卜作嵐反應及水化發展。
由實驗結果得知，飛灰經由水萃程序後，能萃出大量氯鹽、重金屬及硫酸鹽，降低飛灰中硫酸鹽含量及重金屬TCLP之溶出濃度，而鍋爐灰經水萃後仍有13.49 %的SO3，導致取代後漿體膨脹，因此不適用於取代部份水泥。濕式球磨10分鐘內即可降低粒徑至10μm以下，添加10 %能使強度提升6~24 %，健度增加18 %，但是長時間研磨卻會生成CaCO3，對水泥造成傷害。水萃後磷酸穩定搭配研磨10分鐘後能使TCLP低於法規標準，雖然對水泥強度略有影響，但仍優於市售水泥，而且健度能提升11~22 %，因此能真正達到無害化再利用。
Municipal solid waste incinerator (MSWI) fly ashes (reaction fly ash and boiler fly ash) are hazardous wastes that contained complex compositions cause difficult treating. Recycling of the fly ash will be a future tendency in many countries. Fly ash displaced part of cement as a structure material is a potential technique. However, fly ash contains some adverse materials during recycling process, such as chloride, heavy metals, and sulfur, must be removed or stabilized in the fly ash before recycling.
In this study, water extraction and phosphoric acid stabilization with wet ball milling process were used to treat the MSWI fly ash. The water extraction could extract a great quantity of chloride. The phosphoric acid stabilization with wet ball milling process can reduce the particle size of fly ash and stabilize the heavy metals in the fly ash. The analytic methods were used to test the characteristic of the paste as following: the compress strength test and soundness test used to understand the effect of the stabilized finer particles filled the pore of cement paste when the fly ash displaced a part of cement. The XRD and SEM analysis were used to observe the pozzolanic reaction and the hydration development.
From the results of the experiment, after the water extraction process, the chloride, heavy metals, and sulfur could be removed from the fly ash. The TCLP concentrations of heavy metals were reduced at the same time. The boiler fly ash still remains 13.49% of SO3 after the water extraction, which brings on the expansion of the paste, it is not suitable for displaced the cement. The 10 minutes of the milling could reduce the particle size below 10μm. 10% additive of treated fly ash could raise 6~24 % and 18% of the compress strength and soundness, respectively. But the long terms of milling, the CaCO3 would be produced and have an adverse effect on the hydration developing. The reaction fly ash through the water extraction, phosphoric acid stabilization, and 10 minutes milling processes, the TCLP concentration can meet the regulatory limit and the soundness could be raise 11-22%, which can reach the aim of non hazardous and recycling. |
