Abstract Different amounts and types of metakaolin were analyzed and applied for the hydrothermal synthesis of 11 A tobermorite. All synthesized samples were investigated by means of powder XRD combined with Rietveld refinement. Al-substituted 11 A tobermorite was successfully synthesized on the basis of a broad range of compounds characterized by a varying content of metakaolin. Katoite was present depending on the amount of supplied Al3+, which was determined by the dosage of metakaolin. Minor crystalline components included in the two types of metakaolin sources varied greatly in their reactivity under hydrothermal conditions. Despite a different degree of purity, the two types of metakaolin showed corresponding effects at moderate dosages but contrary effects at higher dosages as for the synthesis of 11 A tobermorite. The domain morphology of tobermorite could be associated with Al3+ incorporation for low dosages of metakaolin represented by up to 2 wt.-% Al2O3 in the dry mix. By contrast, Al3+ affected tobermorite lattice parameters at equivalent and even at higher dosages with c reaching 22.95 A at 12 wt.-% Al2O3 in the dry mix.

中文翻译：

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11 Å雪硅钙石的水热合成——在碱性化合物中加入偏高岭土的效果

摘要 分析了不同数量和类型的偏高岭土，并将其应用于11 A雪硅钙石的水热合成。所有合成样品均通过粉末 XRD 结合 Rietveld 精修进行研究。基于以不同含量的偏高岭土为特征的多种化合物，成功合成了铝取代的 11 A 雪硅钙石。Katoite 的存在取决于提供的 Al3+ 的量，这由偏高岭土的剂量决定。两种偏高岭土来源中的微量结晶成分在水热条件下的反应性差异很大。尽管纯度不同，两种偏高岭土在中等剂量下表现出相应的效果，但在较高剂量下对 11 A 雪硅钙石的合成效果相反。对于以干混合物中高达 2 wt.-% Al2O3 为代表的低剂量偏高岭土，雪硅钙石的域形态可能与 Al3+ 掺入有关。相比之下，Al3+ 在等效甚至更高剂量下影响雪硅钙石晶格参数，在干混合物中 12 wt.-% Al2O3 时 c 达到 22.95 A。