| 摘要: | 本研究以大理石污泥、下水污泥、淨水污泥、轉爐礦泥為研究對象，初步評估其再利用於水泥生料之可行性後，在較高取代量的目的下，利用不同水泥係數與不同取代量計算生料配比燒製環保水泥，探討其可行性與添加污泥對環保水泥品質的影響。 經由實驗結果發現，本研究之四種污泥灰份均有達50%以上，具有一定的再利用性，且重金屬含量不高，屬於一般事業廢棄物，對水泥的燒結反而有正面的幫助，此外，在化學組成與晶相組成方面，也都與水泥原料有一定的相似度，故極具有取代之潛力。另外，本研究發現完全使用大理石污泥取代石灰石時，會因為大理石污泥CaO含量少於石灰石、SiO2高於石灰石，導致熔流點下降，又含有較多雜質助融，造成熟料部分熔融，而使結晶效果不佳，以致28天抗壓強度，只到對照組的20%。在改以50%大理石污泥取代石灰石後，可以避免部份熔融的現象，但其中仍有因CaO不足，而使水泥以C2S為主，其28天抗壓強度只到對照組的40%；而另外有稍多CaO生成C3S之水泥，則因為下水污泥而含有過量SO3，使得部分C3S轉變成C2S，因此28天抗壓強度約為對照組的80%。最後再提高HM後之環保水泥，均有足夠之CaO生成足夠的C3S，以致其中能有28天抗壓強度能超過對照組；而因添加下水污泥有過量SO3之水泥，則同上之理由，28天抗壓強度沒能超過對照組，但也都接近對照組，應有其應用價值。此外，本研究亦發現轉爐礦泥不但能取代鐵渣，且其含有的少量ZnO還能幫助水泥燒結。 This study evaluated preliminarily the feasibility of using marble sludge, sewage sludge, alum sludge, and BOF sludge as raw cement materials by drying sludge and analyzing their physical and chemical characteristics. In addition, to enhance the amounts of sludge used, this study calculated and designed the mix of all kinds of sludge under different cement moduli and sludge usage to produce the ecocement. After that, the kinds of physical and chemical character of cement clinker and cement were analyzed, and the microscopic observation of cement paste was analyzed to discuss the feasibility of ecocement and the effect of sludge addition on the properties of ecocement. According to the experimental results, all of the sludge in this study contained more than 50% of ash, and had low content of heavy metal. Therefore, the sludge did not belong to hazardous waste and had positive effect on sintering cement. Additionally, the sludge and raw cement material had the similarity in chemical and crystalline composition, leading to high potential for the sludge to substitute for cement material. Moreover, because of the content of CaO in marble sludge was less than limestone and SiO2 was more than that, the melting point in sintering cement would decreased when marble sludge replaced limestone completely. The marble sludge contained more impurities which help melt, so melting of clinker occurred partially and caused crystallization poorly. The compressive strength at age of 28 days only reached 20% of that in controlled cement paste. In contrast, the partial melting of clinker could be avoided when 50% of limestone was replaced by marble sludge. However, the content of CaO in clinker was insufficient and leaded C2S to be formed primarily in cement. The compressive strength at age of 28 days reached 40% of that compared to controlled cement paste. Some cement was observed more CaO be transformed into C3S, but a part of C3S would be transformed into C2S duo to exceeding SO3 if using large amounts of sewage sludge. In this case, the compressive strength at age of 28 days reached about 80% of that compared to controlled cement paste.The compressive strength at age of 28 days of cement paste would higher than that of controlled past when enhancing cement modulus of HM. The reason was CaO was enough to form abundant C3S. Similarly, the compressive strength at age of 28 days of cement paste could not exceed that of controlled paste because of SO3 in sewage sludge. Nevertheless, the strength approached the controlled past and should have application values. Finally, this study investigated the BOF sludge not only could replace iron slag, but few content of ZnO in it could help sinter cement. |
