微波法制备污泥灰微晶玻璃的工艺及重金属固化效果研究

发布时间：2018-03-25 08:51

  本文选题：污泥灰　切入点：微晶玻璃　出处：《哈尔滨工业大学》2011年硕士论文

【摘要】：城市污泥量随城市化规模的扩大在不断增加,污泥热解技术以其特有的优势成为污泥处理处置的重要途径。污泥热解后会产生一些副产物——污泥灰,如何实现其资源化、无害化成为研究热点。微晶玻璃为一种新型材料,其附加值高,配料范围宽、对重金属固化效果好,得到广泛应用。基于此人们开始利用污泥灰制备微晶玻璃,研究中发现污泥灰利用率不高,集中在20%~60%,其中热处理条件的控制是决定微晶玻璃性能的关键因素,本文在提高污泥灰利用率基础上,对热处理条件进行优化,采用微波法制备出性能优良的微晶玻璃。 本研究以污泥灰为主要原料设计了污泥灰微晶玻璃的配方,污泥灰添加量高达79.05%,对其热处理过程条件进行了优化控制,制备出了性能良好的微晶玻璃。运用XRF分析污泥灰中的化学成分,以微波为热源进行基础玻璃的熔制,确定最佳的熔制工艺条件。对烧制出的基础玻璃进行DTA差热分析测试,确定最佳的热处理制度。因核化阶段对微晶玻璃的晶相形成影响较小,本研究重点对污泥灰微晶玻璃的晶化温度和晶化时间进行了优化,采用XRD和SEM分析试样的析晶种类、形态等微观结构,确定最佳的热处理条件。最后采用TCLP法和Tessier五步连续提取法对污泥灰微晶玻璃的浸出毒性及其重金属的形态分布进行研究,从而表征样品对重金属的固化效果。 试验结果表明:污泥热解后的固体残留物掺加量高达79.05%,相比于已有的污泥灰用量提高了23%,在三层圆柱形刚玉反应器中,以微波为热源,得出制备污泥灰基础玻璃熔制工艺的最佳参数为:以50℃/min的升温速率,升至750℃,保温15min。以污泥灰基础玻璃为原料,重点考察热处理过程中的晶化温度和晶化时间,确定最佳的热处理条件,试验表明当晶化温度为1000℃,晶化时间为2h时,制得的污泥灰基础玻璃结晶度最大,此时晶体的主晶相为钙长石和透辉石的混合晶相,此时的样品体积密度为2.7g/cm~3,吸水率为0.025%,其耐碱性强于耐酸性,显微硬度达8.25GPa,抗弯强度达70.642GPa,制得的样品具有很好的理化性能,得出了制备性能优良的污泥灰微晶玻璃的热处理条件为核化温度820℃,核化时间1h,晶化温度1000℃,晶化时间2h。最后对制得的污泥灰微晶玻璃的重金属固化效果进行了研究,结果表明样品中重金属的浸出量低于国家标准,重金属的形态主要转化成以残渣态形式存在,这种形态在环境中是稳定的,从而证实了污泥灰微晶玻璃的可应用性。
[Abstract]:With the expansion of the scale of urbanization, sludge pyrolysis technology has become an important way of sludge treatment and disposal with its unique advantages. After sludge pyrolysis, some by-products, sludge ash, can be produced, and how to realize the utilization of sludge pyrolysis. The innocuity of glass-ceramics is a new material with high added value, wide range of ingredients, good solidification effect on heavy metals, and has been widely used. Therefore, people began to prepare glass-ceramics with sludge ash. It is found that the utilization ratio of sludge ash is not high, and the sludge ash utilization rate is concentrated at 20%, in which the control of heat treatment conditions is the key factor to determine the properties of glass-ceramics. On the basis of improving the utilization ratio of sludge ash, the heat treatment conditions are optimized in this paper. Glass-ceramics with excellent properties were prepared by microwave method. In this study, the formula of sludge ash glass-ceramics was designed with sludge ash as the main raw material. The amount of sludge ash added was as high as 79.05, and the heat treatment process conditions were optimized and controlled. A kind of glass ceramics with good properties was prepared. The chemical composition of sludge ash was analyzed by XRF, the base glass was melted with microwave as heat source, and the optimum melting process conditions were determined. The DTA differential thermal analysis (DTA) test of the base glass was carried out. Because the nucleation stage has little effect on the crystal phase formation of the glass-ceramics, the crystallization temperature and the crystallization time of the sludge-ash glass-ceramics were optimized in this study. The crystallization types of the samples were analyzed by XRD and SEM. Finally, the leaching toxicity of sludge ash glass-ceramics and the speciation distribution of heavy metals were studied by TCLP method and Tessier five-step continuous extraction method. Thus, the solidification effect of the sample on heavy metals was characterized. The results showed that the amount of solid residue after pyrolysis of sludge was as high as 79.05, and the amount of sludge ash was increased by 23%. Microwave was used as heat source in a three-layer cylindrical corundum reactor. The optimum parameters of the process are as follows: heating rate of 50 鈩，

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