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重金属元素在水泥混凝土中的浸出性及固化机理研究

Research on Lixiviation and Solidified Mechanism of Heavy Metals in Cement and Concrete

【作者】 王彩云

【导师】 兰明章;

【作者基本信息】 北京工业大学 , 材料学, 2004, 硕士

【摘要】 摘 要本文根据我国水泥厂利用回转窑焚烧危险废弃物的现状及今后废弃物处理的发展目标确定了三种不同的水泥配料方案。首先从废弃物焚烧量、侵蚀性溶液、混凝土孔结构三个方面对重金属元素在水泥混凝土中的浸出性进行了对比分析。然后运用 X 射线衍射、电子探针、扫描电镜、核磁共振等方法对重金属元素在水泥中的固化机理做了进一步的研究。结合以上两方面研究客观地评价了利用水泥回转窑焚烧危险废弃物同时制备水泥的可行性,不仅实现了水泥的生态化制备,而且为危险废弃物的处理开辟了新的途径。本文研究结果表明,利用水泥回转窑焚烧危险废弃物后制备的水泥应用于混凝土后 99%以上的重金属元素均可以固化在混凝土基体内部。这些微量重金属元素既可以通过水泥水化产物的物理包容、吸附和化学结合的形式固化于硬化浆体内,也可以通过混凝土结构的密实性降低其渗出,达到稳定化、无害化的目的。不同的重金属离子在水泥中的存在形式和分布不同,铅、镍元素以化合物的形式吸附在水泥颗粒表面。铬元素参与水泥水化反应生成类似于单硫型水化硫铝酸盐结构的含铬结晶相。钴、镉元素取代水泥水化产物中的钙离子,不会使原水化产物的结构发生晶格畸变,形成了相应的含钴、镉硅酸盐结晶相和凝胶相。

【Abstract】 Based on the analysis of the actuality and the target in future of the wastedisposal, this paper adopted three kinds of cement clinker system .And analyzed theimpact of the quantity of waste ,the causticity solution and the pore structure on thelixiviation of heavey metals.Using XRD,EPMA,SEM and NMR to determine thecomposition of hydrated production, the distribution of heavy metals, through whichsolidified mechanism is discussed in detail.Accoring to two studies above, thefeasibility of using cement kiln to deal with hazardous waste and produce cementwas evaluated externally.Which not only realized entironment but also exploited annew way to deal with hazardous waste. In this paper , the conclusion showed that more 99%heavy metals could besolidified in concrete by means of denseness,physical pack, adsorption and chemicalcombination.The heavy meatal of Pb,Zn and Ni were adsorbed on surface of thecement grains by means of compounds in the course of hydrating.Cr participated inhydrating reaction and formed new compounds,which was similar with Afm instructure.The heavy metals of Co,Cd can exchanged with Ca in hydrated productionand be trapped in C-S-H,which formed new Co-containing calcium silicates andCd-containing calcium silicates.

  • 【分类号】TU528
  • 【被引频次】12
  • 【下载频次】623
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