【作者】 时海霞；

【导师】 肖汉宁；

【作者基本信息】 湖南大学 ， 材料学， 2005， 硕士

【摘要】 铬渣是一种有毒的固体废渣,不仅危害人们的身体健康,还对生态环境造成严重污染。铬渣污染问题已引起国家环保部门的高度重视,治理铬渣污染的任务迫在眉睫。铬渣中除了含有Cr₂O₃和有毒的水溶性Cr⁶⁺外,还含有大量的钙、镁、铝、硅的氧化物,这些都是制备玻璃的原料,同时Cr₂O₃又是有效的晶核剂,因此,用铬渣制备微晶玻璃是实现铬渣无毒化处理和资源化利用的有效途径。本文以铬渣、高炉渣两种工业废渣以及石英砂、白云石、方解石、滑石等天然矿物为主要原料,SiC作还原剂,采用熔融法制备了矿渣微晶玻璃。探讨了铬渣的用量、不同CaO/MgO比对微晶玻璃熔制、析出主晶相及材料性能的影响,研究了高温下Cr⁶⁺的解毒机理。实验表明:配方中铬渣质量分数为30⁵0%时,熔制的玻璃流动性好,基本没有浮渣,成型后玻璃未失透; 铬渣质量分数达55%时,玻璃熔体上层浮渣较多,且浇铸成型后玻璃失透; 铬渣质量分数为58%时,玻璃熔体上层漂浮一层黄色物质,经XRD分析为K₃Na（CrO₄）₂。将铬渣、高炉渣同时用于玻璃配方中,获得配方设计中所需的CaO/MgO比。玻璃的晶化温度、主晶相种类、析晶活化能、微晶玻璃的密度、抗折强度及显微硬度都随CaO/MgO比的变化而变化。当铬渣质量分数为40%和45%时,所制备的微晶玻璃的主要晶相组成为透辉石（CaMg（SiO₃）₂）和镁铬尖晶石（MgCr₂O₄）; 当铬渣质量分数为50%时,微晶玻璃的主晶相为透辉石和黄长石((Ca_1.53Na_0.51)(Mg_0.39Al_0.41Fe_0.16)（Si₂O₇）)。采用二苯碳酰二胼分光光度法测定样品中残留Cr⁶⁺的含量。结果表明:铬渣质量分数为40%⁵0%时,样品中Cr⁶⁺含量为0⁰.4mg/L,低于国家标准0.5mg/L; 当铬渣含量高于50%时,残留Cr⁶⁺含量则高于国家排放标准。更多还原

【Abstract】 Chromium slag is a kind of poisonous solid waste. It not only does harm to people’s health but also pollutes the ecological environment seriously. The pollution brought by chromium slag is arousing high attention of national environmental protection department, so it is very urgent to deal with the pollution of chromium slag. In addition to Cr₂O₃ and the poisonous water-solubility Cr6+ ion, the chromium slag contains a great deal of calcium oxide, magnesia, alumina and silica, which are useful compositions of glass-ceramics. Furthermore, Cr₂O₃ is an effective nucleating agent in the glass system. So it is a promising method to realize the detoxification and the resourceful utilization of chromium slag to prepare glass-ceramics by using chromium slag. Besides chromium slag and blast-furnace slag （two kind of industrial residue）, quartz, dolomite, calcite, and talcum were also used as raw materials. SiC was used as reductant. The slag glass-ceramics was prepared by melting method. The effects of the content of chromium slag and diffirent CaO/MgO ratio on the melting performance, the major crystalline and the material properties were discussed. The mechanism of Cr6+ detoxification under high temperature was studied. When the content of chromium slag in the batch was 30⁵0wt%, the flowing property of the melted glass was good. There is hardly no scruff and the glass was transparency. When the content of chromium slag was 55%, there was a lot scruff on the melted glass and the glass was opaque after moulding. When the content of chromium slag was 58%, there was yellow matter suspended on the melted glass, which is K₃Na（CrO₄）₂ identified by XRD. In order to obtain the different CaO/MgO ratio, both chromium slag and blast-furnace slag were used in the glasses. With the CaO/MgO ratio changed, the crystallization temperature of glass, the main crystalline, the activation energy, the density, bending strength and microhardness of glass-ceramics were all changed. When the content of chromium slag was 40wt% and 45wt%, the major crystalline of the glass-ceramics was diopside （CaMg（SiO）₃）₂, and magnesiochromite （MgCr₂O₄）; when the content of chromium slag increased to 50wt%, the major crystalline of glass-ceramics was diopside, and melilite（（Ca₁.53Na₀.51）（Mg₀.39Al₀.41Fe₀.16）（Si₂O₇））. The concentration of residual Cr6+ ion in specimens was determined by diphenylcarbazide（DPC） spectrophotom. When the content of chromium slag was between 40⁵0wt%, the concentration of residual Cr6+ ion in the samples was 0⁰.4mg/L, which is lower than the national standard of 0.5mg/L for vent. When the content of chromium slag was above 50wt%, the concentration of residual Cr6+ ion in the sample was higher than the national standard.更多还原