燃煤电站典型固废中有毒金属形态分析研究

发布时间：2019-05-03 19:27

【摘要】：重金属广泛存在于自然环境中,且普遍具有较强的生物毒性效应。燃煤电站是重金属的重要排放源之一。燃煤电站副产物的排放量逐年增加,其资源化利用也越来越受到重视。在资源化利用的过程中由于重金属的再释放会造成重金属的二次污染。因此,开展燃煤电站固废中重金属分析研究对进一步评价电厂固废二次利用过程中重金属的环境毒性效应和迁移转化规律具有十分重要的意义。本文通过HNO_3-HF消解体系对11家燃煤电站的入炉煤、粉煤灰、炉渣和石膏样品中砷的含量进行了测定。结果表明,煤中砷含量为2.5-8.0μg/g;粉煤灰中9.39-93.91μg/g;炉渣中2.3-19.7μg/g;脱硫石膏中1.0-3.0μg/g。通过相关性分析得知脱硫石膏中的砷主要来源于脱硫系统对粉煤灰的吸附和吸收。此外,燃煤电站副产物中砷的溶出率较低,但仍具有一定的二次污染风险为了进一步研究固废中砷和汞的存在形态,建立了液相色谱-氢化物发生-原子荧光光谱在线连用分析系统。该系统快速、稳定、准确。使用该分析系统测定了脱离石膏中可溶态砷的赋存形态。结果表明,脱硫石膏中可溶态砷主要以毒性较强的As(III)形式存在。为了测定石膏中汞的存在形态,建立了高温热解-原子荧光光谱连用分析系统。考察了不同形态汞化合物的热解温度,热解温度由低到高依次是HgCl2,黑色HgS,HgO,红色HgS,HgSO4。此外,通过程序升温分离测定了多个脱硫石膏样品中的汞形态,结果显示,脱硫石膏样品中的汞主要以HgS和HgO的形式存在。
[Abstract]:Heavy metals exist widely in natural environment and have strong biotoxic effects. Coal-fired power station is one of the important sources of heavy metal emission. The emission of by-products from coal-fired power stations increases year by year, and its resource utilization has been paid more and more attention. The secondary pollution of heavy metals will be caused by the re-release of heavy metals in the process of resource utilization. Therefore, the analysis of heavy metals in solid waste of coal-fired power plants is of great significance to further evaluate the environmental toxic effects and migration and transformation laws of heavy metals in the secondary utilization of solid waste of coal-fired power plants. The contents of arsenic in coal, fly ash, slag and gypsum samples from 11 coal-fired power stations were determined by HNO_3-HF digestion system. The results show that the arsenic content in coal is 2.5-8.0 渭 g / g, 9.39-93.91 渭 g / g in fly ash, 2.3-19.7 渭 g / g in slag and 1.0-3.0 渭 g / g in desulphurization gypsum. The correlation analysis shows that arsenic in desulphurization gypsum mainly comes from the adsorption and absorption of fly ash by desulphurization system. In addition, the dissolution rate of arsenic in by-products from coal-fired power stations is relatively low, but there is still a certain secondary pollution risk in order to further study the forms of arsenic and mercury in solid waste. An on-line analytical system for liquid chromatography-hydride generation-atomic fluorescence spectrometry (AFS) was established. The system is fast, stable and accurate. The speciation of soluble arsenic in dissociated gypsum has been determined by this analytical system. The results show that the soluble arsenic in desulphurization gypsum is mainly in the form of As (III) with strong toxicity. In order to determine the mercury species in gypsum, a high temperature pyrolysis-atomic fluorescence spectrometry (AFS) analysis system was established. The pyrolysis temperature of different mercury compounds was investigated. From low to high, the pyrolysis temperature was HgCl2, black HgS,HgO, red HgS,HgSO4.. In addition, mercury speciation in several samples of desulphurization gypsum was determined by temperature programmed separation. The results showed that mercury mainly existed in the form of HgS and HgO.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X773

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