储碳固废（核素及飞灰）型水泥材料的理论及实验研究

发布时间：2018-03-19 12:40

本文选题：有害废弃物　切入点：水泥固化　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着人类社会现代化水平逐渐提升,工业日益发达,城市生活水平日新月异,人们的幸福感也不断提高。但是随之而来的环境问题不容忽视,温室气体的排放造成全球气候变暖,核工业废弃的放射性废料需妥善安置,城市生活垃圾处理困难导致许多城市上演垃圾围城,随着环境的恶化,环保已经成为当今社会的核心议题之一。本文将着眼以上提及的热门环保问题,探讨利用水泥固化技术固化核废料和垃圾焚烧灰,并用超临界碳化技术将二氧化碳气体储存于固化体中,形成储碳固废的新型水泥材料。混凝土的碳化一直被认为是钢混结构的主要病害之一,但是对于无需配筋的水泥材料,碳化可改良其微观结构,降低其孔隙率,提高其密实度,这些都是有益于材料性能的良性变化。水泥材料放置在超临界二氧化碳环境时,可在数个小时完成自然条件下数年甚至十数年才能完成的碳化过程,因此将超临界碳化技术应用于水泥基材料有其可开发利用的前景。如今国内外对水泥材料固化危险废弃物和污染物的研究越来越多,水泥固化技术以其技术成熟、固化性能稳定安全的优势已成为目前应用最广泛的废弃物固化手段。本文将结合超临界碳化和水泥固化技术,深入研究固化体安全性能以及碳化对其性能的影响。研究过程采用实验和数模相结合的方式进行。数模过程中通过引入参数Cmax提高了原有碳化模型的适用范围,同时在模型中首次考虑了碳化对固化体内离子化学浸出活性的影响,提高了结合模型的精度和适用性。实验中制作了含有非放射性核素同位素和垃圾焚烧飞灰的水泥固化体,对固化剂进行了直接浸出和碳化后浸出的浸出实验,观测浸出过程中浸出率的变化,对比碳化前后的结果,研究碳化对固化体浸出性能的影响。根据数值模型理论和已有参数在多物理场耦合有限元软件COMSOL中建立了碳化和浸出的结合模型,模拟了固化体碳化和浸出的实验过程。综上,理论、实验和模拟三位一体,共同验证了碳化对固化体浸出性能的影响以及数值模型的适用性。
[Abstract]:With the gradual improvement of the level of human society's modernization, the development of industry, the rapid development of urban living standards, and the improvement of people's happiness, however, the environmental problems that follow can not be ignored. Greenhouse gas emissions cause global warming, radioactive waste from the nuclear industry needs to be properly disposed of, and difficulties in disposing of municipal domestic waste have led to garbage besieging in many cities, as the environment deteriorates. Environmental protection has become one of the core issues in today's society. This paper will focus on the hot environmental problems mentioned above, and discuss the use of cement curing technology to cure nuclear waste and waste incineration ash. The carbon dioxide gas is stored in the solidified body with supercritical carbonization technology to form a new cement material for carbon storage and solid waste. The carbonation of concrete has always been considered as one of the main diseases of steel and concrete structure, but for cement materials without reinforcement, Carbonation can improve its microstructure, reduce its porosity and increase its compactness, which is beneficial to the good change of material properties. When the cement material is placed in supercritical carbon dioxide environment, A carbonation process that can be completed in hours for years or even more than a decade under natural conditions, Therefore, the application of supercritical carbonization technology to cement based materials has a promising prospect. Nowadays, more and more researches on cement curing hazardous wastes and pollutants are carried out at home and abroad, and cement curing technology is mature with its technology. The advantage of stability and safety of curing performance has become the most widely used waste curing method. In this paper, supercritical carbonization and cement curing technology will be combined. The safety performance of solidified body and the influence of carbonization on its performance are studied in depth. The research process is carried out by the combination of experiment and digital simulation. In the process of digital simulation, the application range of the original carbonization model is improved by introducing the parameter Cmax. At the same time, the influence of carbonation on the ion leaching activity in the solidified body was considered for the first time, and the accuracy and applicability of the combined model were improved. In the experiment, the cement solidified body containing non-radionuclide isotope and waste incineration fly ash was prepared. The experiments of direct leaching of curing agent and leaching after carbonization were carried out, the change of leaching rate during leaching process was observed, and the results before and after carbonization were compared. The influence of carbonization on the leaching performance of solidified body is studied. Based on the numerical model theory and the existing parameters, the combined model of carbonization and leaching is established in the multi-physical field coupled finite element software COMSOL, and the experimental process of carbonation and leaching of the solidified body is simulated. The influence of carbonation on the leaching properties of the solidified body and the applicability of the numerical model are verified by the trinity of theory, experiment and simulation.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ172.1;X705

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