【作者】 张平萍；

【导师】 叶瑛；

【作者基本信息】 浙江大学 ， 矿物学、岩石学、矿床学， 2008， 博士

【摘要】 坡缕石又称为凹凸棒石,是一种具有链层状结构的镁铝硅酸盐矿物,早在19世纪就已被发现。由于坡缕石粘土矿物具有特殊的晶体结构（一维孔道结构）、特殊的物理化学性质（吸附性质、胶体性质、橡塑材料增强性质）、特殊的晶体形态（天然纳米纤维材料）、特殊的成因（与中国东部第三纪玄武岩喷发活动有关的干旱半干旱湖沉积）,因此对此种矿物的研究不仅具有理论意义,还具有应用价值。本论文的研究目的是说明坡缕石在各种条件活化过程中结构和成分的变化;研究不同酸处理条件对坡缕石晶格重建的影响,以及不同金属离子对坡缕石晶格重建的效果;通过三种不同粘土矿物对阳离子吸附、脱吸附性质的比较,以及以坡缕石为原料制备沸石分子筛的研究,扩展坡缕石在纳米材料科学的应用领域并提高其经济价值。本文以江苏盱眙含白云质坡缕石为原料,经提纯后,分别于不同的条件下进行不同方式的活化,酸活化后的样品进一步进行阳离子吸附和脱吸附实验。利用XRD,SEM和TGA分析研究不同活化条件下坡缕石的结构变化,AAS分析研究反应溶液中离子成分的变化。通过研究,取得以下认识:1)在较低温度下（一般小于60℃）,3mol/L浓度以内的盐酸对坡缕石结构破坏不明显;当温度较高时（一般高于70℃）盐酸对坡缕石结构的破坏程度明显加强、加快。2)当坡缕石结构完全被破坏后,即八面体阳离子完全溶出、硅氧四面体的支撑结构完全坍塌,坡缕石结构无法重建;当坡缕石结构被部分破坏后,即部分八面体阳离子被氢离子替代、硅氧四面体还未遭到破坏,坡缕石在水热条件下有晶格发生重建的趋势。3)不同的金属阳离子对坡缕石晶格重建的效果不同,这与阳离子的水化热等有关。4)由于蒙脱石、沸石与坡缕石吸附阳离子的原理不同,吸附金属离子后的不同粘土在一定盐度溶液中的脱吸附率也不同。坡缕石在0.3%浓度的NaCl溶液中脱吸附率要较蒙脱石和沸石低得多。5)碱溶液对坡缕石的作用主要表现在两个方面:a)OH^-对Si—O—Si键的剪切,b)Na⁺对八面体阳离子的交代,其中这种交代具有选择性,置换顺序为:Al³⁺＞Fe³⁺(Fe²⁺)＞Mg²⁺。坡缕石经碱溶处理后可以转变成蒙脱石和方沸石。其中碱浓度的增加有利于蒙脱石的生成,温度的升高则有利于方沸石的生成。更多还原

【Abstract】 Palygorskite is a chain-layer magnesium-aluminum silicate.Since it was discovered in the 19^th century.It’s particles possesses special crystal structure such as one dimension pore structure,special physical-chemical properties such as strong absorbability,colloidal properties,reinforcement in rubber and plastics materials etc.,special crystal morphology such as natural nano-fibre material and special cause of formation,e.g.precipitation in droughty and semi-droughty lake which was related to eruption of tertiary basalts in east China.The study on properties and modification mechanism of palygorskite is important for its performance and prospect in industry.The objectives of the thesis are that explain the transformation of structure and component in different active conditions,investigate the influence of different acid treatment methods on crystal lattice’s reconstruction and effect of various metal cations on crystal lattice’s reconstruction,compare properties of cation adsorption and removal by three different clay minerals and prepare zeolite using palygorskite as raw material.These study would extend the applied field in nano-material science and increase the economic values of palygorskite.Using palygorskite with dolomite from Xuyi,Jiangsu Province as raw material,after purified,treated in different conditions separately.Then do cation adsorption and removal experiment using acid-activated product.The variation of structure with different activated condition was characterized using X-ray diffraction（XRD）,scanning electron microscope（SEM） and thermo gravimetric analysis（TGA）,and the componential variation of ions in solution was obtained by atomic absorption spectrometry（AAS） measurement.Main achievements of the thesis is as follows:1) In lower temperature（commonly less than 60℃）,the structure of palygorskite is destroyed faintly by hydrochloric acid within 3mol/L concentration.When the temperature increase（commonly more than 70℃）,the breakage of structure would strengthen and accelerate distinctly.2) Palygorskite’s structure can’t be restored when the structure was destroyed completely.This time,most of octahedral cations leached and configuration supported by SiO₄ tetrahedron collapsed.When palygorskite’s structure was destroyed partly,that was H⁺ partly substituted for octahedral cations and SiO₄ tetrahedron still retained special construction,the crystal lattice of palygorskite had tendency to be reconstructed.3) The effect of crystal lattice’s reconstruction is related to hydrothermal heat of metal cations.The higher hydrothermal heat’s value is,the better the effect of crystal lattice’s reconstruction is.4) The mechanism of adsorption of cations by montmorillonite,zeolite and palygorskite is various,so there removal ratios vary in certainty salinity solution. The removal ratio of palygorskite is lower than montmorillonite and zeolite’s.5) There are two kinds of processes in the reaction between alkali solution and palygorskite.One is shear stress of OH^- on Si-O-Si bond,another is substitution of Na⁺ for octahedral cations and substitution sequence is Al³⁺＞Fe³⁺ (Fe²⁺)＞Mg²⁺.Palygorskite would transform into montmorillonite and analcime.The higher alkali concentration is favorable for emergence of montmorillonite,while the higher temperature is favorable for emergence of analcime.更多还原