【作者】 杨阳；

【导师】 李政一；

【作者基本信息】 北京工商大学 ， 环境工程， 2010， 硕士

【摘要】 膨胀蛭石是一种优良的保温耐火、吸音隔热、耐冻蚀的环保节能材料,应用领域十分广泛。我国蛭石矿产资源丰富,但膨胀机理不明确,没有相应的膨胀率测定方法,开发利用与国外相比存在着产品品种少、膨胀工艺简单、细粒蛭石的利用率低等问题。为了研究膨胀机理,以河北灵寿县工业蛭石为实验样品,分别进行了X射线能谱分析、红外光谱分析以及X射线衍射分析,研究了该矿蛭石的结构特征以及膨胀特性,发现样品中主要含有蛭石和水黑云母成分,随着温度升高逐渐失水,500℃时蛭石完全脱去层间水,整个结构成为“滑石层”的形式,蛭石的体积发生明显的膨胀。但温度过高达到900℃时,蛭石中的Si-O四面体结构被破坏,反而影响蛭石的膨胀性能。利用X射线能谱仪分析了工业蛭石所含的阳离子类型,并采用氯化铵-乙醇法测定了蛭石的阳离子交换容量为55.6mmol/100g。分别采用不同浓度的硫酸、碳酸钠和十六烷基三甲基溴化铵对蛭石精矿进行了改性,发现酸化、钠化和有机改性后蛭石样品的阳离子交换容量分别提高到了73.5mmol/100g,60.2mmol/100g和68.8mmol/100g。针对我国对蛭石膨胀率的测定没有统一标准的现状,分别从单片蛭石的体积膨胀率和集合膨胀率两方面对蛭石膨胀率的测定方法进行了探讨,对比分析了现有测定蛭石膨胀率方法的优势和局限性。最后提出从蛭石的微观形貌来表征膨胀蛭石的品质,通过比表面积及孔隙分析仪测定蛭石的比表面积及孔径来确定蛭石的膨胀率。传统的蛭石膨胀工艺是燃料加热法和电加热法,随着蛭石膨胀工艺发展,目前主要还有微波膨胀和化学膨胀等方法。本文研究了片径、加热温度、加热时间和改性条件等单因素对蛭石膨胀率的影响,正交实验结果表明,片径为1-2mm,20%的双氧水改性,700℃下加热时间60s,是蛭石膨胀的最佳工艺条件。随着对蛭石膨胀工艺的深入研究,可进一步促进蛭石环保节能材料的开发与应用。更多还原

【Abstract】 Exfoliated vermiculite is an excellent thermal and acoustic insulated environment-friendly and energy-saving material, with the characters of fire-resistant, corrosion-resistant and freeze-resistant, which can be applied very widely. There’s abundant of vermiculite mineral resources in our country, but the expansion mechanism of vermiculite is not clear, without a corresponding expansion rate determination, the development and utilization has many problems such as less product variety, simple rough expansion process, low utilization of fine particle vermiculite compared with foreign countries.To study the mechanism of expansion, using the industrial vermiculite from lingshou of hebei as experimental material, characterized it with X-ray spectrum analysis, infrared spectroscopy and X-ray diffraction analysis, and studied the structural feature and expansion characteristics of vermiculite. It revealed that the raw material mainly composed of vermiculite and hydrobiotite, dehydrating as the temperature increases gradually. Vermiculite lost interlayer water forming a“talc layer”structure till 500℃, and the volume of vermiculite expanded apparently. However, when the temperature reached 900℃, the Si-O tetrahedron structure was destroyed, thereby affecting the expansion property of vermiculite.Analyzing the tapies of cation in industrial vermiculite by X-ray energy dispersive spectrometer, the cation exchange capacity(CEC) of vermiculite was 55.6mmol/100g measured by ammonium chloride-ethanol method. The vermiculite was modified by different concentrations of sulfuric acid, sodium carbonate, and hexadecyl trimethyl ammonium bromide. The results indicated that the CEC of acidized vermiculite、Na-modified vermiculite、organo-intercalated vermiculite increased to 73.5mmol/100g,60.2mmol/100g and 68.8mmol/100g, respectively.Aiming at the current situation that there is no uniform standard for the determination of vermiculite expansion ratio, the measuring methods were discussed respectively from individual and cumulative volume expansion ratios, according to the comparison and analysis, we got the advantages and limitations of existing measuring methods of vermiculite expansion ratio. Finally, based on microstructure of vermiculite, this paper put forward a new method to characterize quality of expanded vermiculite, using the BET specific area and pore radius of vermiculite tested by Accelerated Surface Area and Porosimetry (ASAP) to ascertained the vermiculite expansion ratio.The traditional vermiculite expansion process was thermal exfoliated by fuel or electricity. With the development of vermiculite technology, the main process at present was microwave exfoliated and chemical exfoliated. The main factors affecting vermiculite expansion ratio were size, heating temperature, heating time and modified condition, the orthogonal experiment indicated that the optimum processing conditions were: the size was 1-2mm, hydrogen peroxide was 20%, heating temperature was 700℃, heating time was 60s. It could further accelerate the exploitation and application of the environment-friendly and energy-saving materials with the in-depth study of vermiculite processing.更多还原