| 摘要: | 本研究將以焚化灰渣、大理石污泥、下水污泥進行環保水泥之燒製，尤其對高氯含量之灰渣，除預先除氯外，亦考慮在燒製過程嘗試使其形成氯鋁酸鈣固定與熟料中，而成為環保水泥之一部分，以解決氯鹽之干擾。 原料前處理研磨後，利用水泥配料係數計算配比之環保水泥生料，再以實驗室高溫爐燒結處理，燒成兩系列六組不同配比之環保水泥熟料，進行各項物化特性分析以及工程性質與水化反應行為之探討。實驗結果如下：實驗燒製之兩系列六組環保水泥熟料，其游離石灰量皆小於1，且製程燒失量介於25% -30%間，符合實廠窯燒水泥之品管規範。其重金屬溶出濃度均符合法規標準值，後續資源化利用作為土木工程材料深具潛力。研究中所燒製各組環保水泥熟料與波特蘭水泥成份類似，其單礦物組成除了含有C3S、C2S、C3A及C4AF，還有環保水泥特有的C11A7CaCl2等晶相物種。OEC系列環保水 泥漿體部分初終凝時間與OPC比較有略微的提早的現象，但差異並不大且也符合規範；REC系列環保水泥漿體部分初終凝時間明顯的提前許多。環保水泥漿體抗壓部分跟初終凝有正向的關係，在OEC系列環保水泥漿體與OPC強度發展類似，而REC系列環保水泥漿體則有早強的現象發生，這也是含氯環保水泥的特性。由XRD之物種分析得知，環保水泥漿體主要產物為CH、C-S-H膠體，並無明顯差異。此外，環保水泥漿體會產生部分之Mg(OH)2，這是利用大理石污泥取代石灰石的原因。由FTIR分析結果顯示，隨齡期發展均可發現，環保水泥漿體矽酸鈣水化產物C-S-H膠體則具有強的Si-O伸縮振動頻帶；碳酸鹽物種為C-O鍵結；此外，CH為-OH伸縮振動頻帶。由核磁共振(NMR) 技術以29Si為核種進行分析結果顯示，環保水泥漿體之水化產物Q0 峰會隨齡期增加逐漸轉移至Q1與Q2峰，且水化程度與聚矽陰離子皆有隨齡期而增加之趨勢。 The high chlorine content in the incinerator ash has limited the use of it as part of the raw material for producing ecocement. It is possible, however, to calcine chlorine-containing raw meal into calcium chloroaluminate, one cement hydrate mineral, which can not only fix the chlorine in it but also function just like the other cement clinker minerals. This study investigated the feasibility of producing ecocement, using chlorine-containing incinerator ash, marble sludge, and sewage sludge as raw materials, and the hydration characteristics of the resulting cement clinkers. In the design of the raw materials incorporated the tested wastes, a computational model was established on the basis of cement modulus to formulate possible range of the compositions of raw meals with tested chlorine contents in the raw materials verifying from 1.5-37.8 %(w/w). The calcination of raw materials into cement clinker minerals were examined and the hydration characteristics of the resultant ecocements and the engineering properties of their pastes were studied including the compressive strength, speciation and the degree of hydration, as compared to those of ASTM type I ordinary Portland cement (OPC).In this study, the amount of free CaO decreased to less than 1 %(w/w) and the LOI for all tested meals met the eco-cement criteria. In conclusion, the formation of major cement clinker minerals such as C3S, C2S, C3A, C4AF and C11A7CaCl2 were confirmed in all the eco clinkers. Ecocement produced with was washed incinerator ash, marble sludge, and sewage sludge as raw meal (referred to as ordinary ecocement, OEC) showed both the initial and the final setting times were slightly shortened or similar to those of OPC. However, ecocement produced using chlorine-containing incinerator ash, marble sludge, and sewage sludge as raw meal (referred to as chlorine-containing ecocement, REC) exhibited both the initial and the final setting times were significantly shortened with the increasing chlorine content in the RECs. On the other hand, the compressive strength development of OEC samples showed slightly decreased as compared to that of OPC samples, whereas the REC samples showed a reversed trend. The development of compressive strength outperformed those of OPC samples during the early 28 days, showing the contribution by the hydration of the C11A7CaCl2 which characterizes the rapid setting and strength development of the REC samples. The results of XRD analysis confirmed that OPC, OEC and REC showed common hydration products of CH and CSH gel, the OEC and REC exhibited the presence of hydration product, (Mg(OH)2), which were supposed contributed by the use of marble sludge in the raw meals. The FTIR analysis of the OEC and REC pastes cured at 90 days containes three wavenumbers: the first wavenumber was mainly due to the Si-O bonds of calcium silicate hydrates (CSH); the second wavelength represents the C-O bonds of the calcium carbonate (CaCO3); and the third wavelength the decomposition of calcium hydroxide (Ca(OH)2). The results indicate the hydration products of the tested OEC and REC samples. The hydration products of both OEC and REC pastes, as analyzed by 29Si NMR techniques showed that Q0 peak decreased and O1 peake increased with increasing curing age. And the hydration degree and length of the linear polysilicate anions, as estimated on the basis of the Q0 and Q1 peaks, showed the increasing trend with increasing age. |
