- 學位論文
焚化飛灰去除氯鹽及重金屬之研究
A Study on Removal Soluble Salts and Heavy Metals from Incinerator Fly Ash
摘要
國內廢棄物之處理早期大多以衛生掩埋做最終處置，由於台灣人口密度高，及受土地容量限制，因此國內廢棄物逐漸以焚化為主要處理方式，以達到廢棄物減量之目的。然而焚化的過程中產生之衍生物為底渣及飛灰。根據環保署統計，2012年而焚化後所衍生之灰渣產量約為134萬噸；其中底渣為106萬噸，飛灰(包括反應生成物)為28萬噸，因此焚化灰渣的處理亦是另一個重要議題。目前底渣再利用率為81%，焚化飛灰則是較少再利用，其主要因素在於焚化飛灰具高重金屬、水溶性鹽類和有機物質，所以一直以來被主管機關認定為有害事業廢棄物，因此若能有效去除內部之危害物質，則可作為再利用之材料，同時亦降低環境之污染。 本研究採用省水、省時之擦洗技術，去除焚化飛灰重金屬及水溶性氯離子，進而達成TCLP溶出試驗限定標準值。擦洗為選礦工程常用之方法，藉由礦粒間的碰撞作用，其可分離附著於表面之雜質、黏土塊及氧化物薄膜等。研究結果顯示，以液固比率，先高後低之二階段擦洗試驗進行處理，可將焚化飛灰中重金屬毒性溶出值降至法規限定值以下，水溶性氯離子去除率也可達95.2%。此外，擦洗處理之用水量較少，節省成本。擦洗後之焚化飛灰製成無機聚合物，經TCLP試驗，皆未偵測出其重金屬毒性溶出值。由此可知經擦洗試驗後，焚化飛灰具有資源化之潛力。
並列摘要
In early stage, landfill was a major treatment way for municipal solid waste (MSW) in Taiwan. However, incineration has become a significant method for MSW treatment, because of the rising difficulty to find suitable sites for traditional landfill. According to EPA of Taiwan, there were 289157 tons incinerator fly ashes produced in 2012. With growing public concerns and rigorous regulatory requirements, the hazardous wastes need further treatment for reutilization. In this study, attrition scrubbing technology was used to achieve the standard limitation of Toxicity Characteristic Leaching Procedure (TCLP) tests, removal water-soluble chloride and heavy metals from incinerator fly ashes. Attrition scrubbing is a mineral processing method. Throughout the collisions within mineral particles, the impurities, clay blocks and the oxide film attached on the surface of mineral particles could be removed. The experiment results show that the washed fly ash can be passed the TCLP test and the water-soluble chloride can be removed 95.2% by two-step attrition process. These washed materials show great potential for engineering applications.