【作者】 王公领；

【导师】 丁浩；

【作者基本信息】 中国地质大学（北京） ， 岩石矿物材料学， 2009， 硕士

【摘要】 绢云母是一种重要的工业矿物原料,具有优良的物理化学性能,广泛应用于造纸、陶瓷、涂料、塑料、橡胶、化妆品等工业领域。聚合物/绢云母纳米复合材料不仅能够最大程度地发挥绢云母优良特性,而且能够附加新的功能,是提高绢云母价值和实现高档次应用的重要手段。但是绢云母结构非常稳定,难以直接用于制备聚合物/层状硅酸盐（PLS）纳米复合材料。本论文以热活化绢云母为对象,研究了硝酸处理对绢云母结构中铝溶出和层间剩余电荷量的影响,再对酸处理绢云母进行钠化修饰以获得层间阳离子交换性。经正交实验和单因素实验得到了酸处理和钠离子交换的最佳处理工艺。对酸处理和钠化修饰产物进行了表征,对过程机理进行了探讨。热活化绢云母经硝酸处理,结构中Al³⁺离子有较大量溶出。在硝酸溶液浓度5mol/L,反应温度95℃,搅拌时间4h,固液比3%的优化条件下,Al³⁺离子溶出量高达30mg/g左右。XRD分析表明,绢云母的晶体结构有一定程度的畸变,部分层间域出现扩张现象,但其晶体结构总体上依然完整。27Al NMR分析表明绢云母结构中四配位铝和六配位铝均被溶出。化学分析结果表明绢云母结构层中和层间的阳离子均被溶出,导致其结构单元负电荷从1.00降低到0.78,绢云母硝酸处理前后的Zeta电位测定结果证明了该结论。钠化修饰后绢云母形成了一定的阳离子交换能力。最佳实验条件为NaCl溶液浓度6mol/L,反应温度95℃,搅拌时间1h,重复3次。制备得到的绢云母的阳离子交换容量（CEC）最高达29.07mmol/100g。钠离子交换绢云母的晶体结构畸变程度变得更大,但仍然保持完整。对正交实验和单因素实验工艺条件的研究表明,硝酸处理及钠离子交换反应过程属于离子交换反应。获得足够高活化能的H⁺离子越多,溶出的Al³⁺离子及其它阳离子的量越高。Na⁺离子水化能低,交换性好,溶液中Na⁺离子的浓度越高,能够有效交换层间K⁺离子的部分越多,从而钠化产物的CEC值越大。更多还原

【Abstract】 Sericite is a kind of important industrial mineral raw materials with excellent physical and chemical properties. It has been widely applied in industrial fields such as paper making, ceramics, coatings, rubber, plastics and cosmetics. Polymer/sericite nanocomposites can not only farthest exert outstanding characteristics of sericite but also add new functions. So the preparation of polymer-layered silicate （PLS） nanocomposite based on sericite is an important means to improve the application values of sericite and realize high-level utilizations. However, the structure of sericite is firmly stabilized, it is hard to directly prepare PLS nanocomposite.Sericite raw material was calcined beforehand and its structure was activated to some extent. Then it was further modified through acid treatment and Na-exchange treatment. Influences of acid treatment on aluminum dissolution and interlayer negative charge of sericite structure were studied. Cation exchangeability was obtained by Na-exchange treatment. Optimum process conditions were determined by orthogonal experiments and single-factor experiments. The products were characterized and the action mechanisms were discussed.Relatively large amount of Al³⁺ cations were dissolved from heat-treated sericite using nitric acid. The dissolution amount reached around 30mg/g at the optimal processing conditions of concentration of nitric acid solution 5mol/L, reaction temperature 95℃, agitation speed 4h and solid-liquid ratio 3%. Results of XRD analyses show that the structure of sericite was distorted but not collapsed, and part of interlayer spacing was expanded. Results of ²⁷Al NMR analyses indicate that both 4-fold and 6-fold aluminum in the structure were dissolved. Because the cations in interlayer and layer were dissolved, the net negative charge reduced from 1.00 to 0.78. And this was proved by the Zeta potentials of sericite before and after acid-treated.Certain cation exchangeability was gained by Na-exchange treatment of acid-treated sericite. Optimum process conditions were determined: concentration of NaCl solution 6mol/L, reaction temperature 95℃, agitation time 1h and repeated for 3 times. Optimal CEC value reached 29.07mmol/100g. The distortion degree was larger than that of acid-treated sericite, but the structure of sericite was still integrated.Researches on the processing conditions by orthogonal and single-factor experiments indicate that acid treatment and Na-exchange treatment are ion exchange reaction. The dissolution amount of Al³⁺ cations and other cations increased with increasing H⁺ cations with enough activation energy. The hydration energy of Na⁺ cations are relatively low and its exchangeability is excellent. The CEC value of Na-exchanged products increased with increasing concentration of Na⁺ cations that can efficiently exchange K⁺ cations in the solution.更多还原