濕式研磨都市垃圾焚化飛灰程序對鉛之穩定效率及機制探討

A study on the Pb stabilization efficiency and mechanism during the wet ball milling for MSWI fly ash

鄭人豪(Jen-Hao Cheng)

指導教授 ： 高思懷

淡江大學/工學院/水資源及環境工程學系碩士班/碩士(2011年)

https://doi.org/10.6846/TKU.2011.00027

摘要

都市垃圾焚化飛灰具有高鹼度、高氯鹽及大量重金屬的問題，屬於有害事業廢棄物，飛灰中的氯會與重金屬形成易溶出鹽類，因此本研究將水萃程序作為前處理去除大量氯鹽，再以濕式研磨技術穩定重金屬。研究中主要探討飛灰在濕式研磨環境下重金屬穩定效率及機制，並於實驗中添加已知濃度鉛液，觀察重金屬鉛受機械力研磨作用前後相關之變化。由初步水萃灰重金屬溶出結果得知，Pb之TCLP溶出值為9.76 mg/L，逾法規標準，故後續針對Pb討論研磨穩定重金屬。
由實驗結果得知，1:1混合的研磨球粒徑研磨穩定重金屬效果比單一小尺寸研磨球粒徑佳，另外，水萃灰與10 g/L、40 g/L鉛液經8小時研磨程序再以TCLP的方式萃取，Pb穩定效率分別為93 %、82 %，在水萃灰與40 g/L鉛液共同研磨0-20小時，結果顯示長時間研磨Pb的晶相物種難以被鑑定出，由SEM觀察出研磨灰外觀呈固溶狀，使得重金屬鉛穩定於飛灰中；由數學式推算表示，機械力研磨機制可以增加37-40 %的重金屬鉛穩定效益，化學反應形成穩定化合物只有增加12 %穩定效率，鉛形成穩定吸附可增加18 %穩定效率，最後，XRD鑑定Pb經過8小時研磨由易溶出的Pb7O6Cl2型態轉變為較難溶的PbO2穩定型態，證實機械力研磨作用確實能有效降低重金屬鉛的溶出並穩定於飛灰。

關鍵字

飛灰 ； 研磨 ； 重金屬 ； 穩定 ； 機制

並列摘要

Municipal solid waste incinerator (MSWI) fly ash with high alkalinity, high chloride and heavy metals problems. The chlorine and heavy metal will form easily dissolved salts in fly ash. In this study, the water extraction procedure as a pre-treatment to remove plenty of chlorine salts. Then stability of heavy metals with wet ball milling technology. The study is to investigate heavy metal stabilization efficiency and mechanism during the wet ball milling for MSWI fly ash. And adding a known concentration of lead fluid in experimental. Observed the lead by mechano-chemical of change. According to the results of water-extracted fly ash leaching of heavy metals, the lead of the leached concentration was 9.76 mg/L. It was higher than with the USEPA regulatory limit of 5mg/L. Therefore, the future tendency is to discuss Pb stabilization by milling.
According to the experimental results, stabilizing effect of lead using the mixing ratio of milling media 1:1(diameter of milling media is 1 and 5 mm respectively) is better than a single small diameter 1mm milling media. However, the mutual milling of the water-extracted fly ash and concentration 10g/L、40g/L lead fluid was 8 hours and then extractable lead by TCLP. The results show that 93%、82% of lead stabilization efficiency respectively. The water-extracted fly ash and concentration 40g/L lead fluid milled 0-20 hours. The results by XRD analysis showed with the long milled of the lead crystalline particles were hardly to identify. The observation of SEM indicates that milled fly ash to from solid solution which led the lead into fly ash to result in stabilization. According to mathematical projections, mechano-chemical treatment can increase 37-40% stabilization efficiency of heavy metals. Chemical reaction to form a stable compound that only 12% stabilization efficiency of heavy metals. The lead to form a stable adsorption can increase 18% stabilization efficiency of heavy metals. Finally, the results by XRD analysis showed the lead milled 8 hours. The predominant species of lead was identified to be Pb7O6Cl2 into insoluble state PbO2. Confirmed that mechano-chemical treatment can effectively inhibited the elution of lead from fly ash.

並列關鍵字

fly ash ； milling ； heavy metal ； Stabilization ； mechanism

參考文獻

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