Qualitative and quantitative chemical-mineralogical characterisation of Portlandcement clinkers by means of scanning electron microscopy techniques

在上一个项目中，建立了表征水泥熟料的EBSD方法。如项目报告所述，EBSD-EDX分析首次提供了以空间分辨化学晶体学方式表征水泥熟料的可能性。这意味着可以确定所有熟料相的分数、化学成分（包括微量元素和痕量元素）、结晶度和微晶尺寸。这是第一次可以获得细粒熟料相的晶粒尺寸（1-10 μm）。在项目的继续过程中，将进一步开发之前在水泥行业成功建立的EBSD-EDX技术，以实现对所有熟料相的高分辨率、统计安全分析。Belit：在之前的项目中，我们发现贝利特的EBSD图谱显示其结晶度较低，即使是在自形晶体形状下观察，也只能检测到非常小的结晶区域。在更灵敏、高分辨率的EBSD相机的帮助下，将在后续项目中分析波特兰水泥熟料中贝利特的精细结构。此外，替代的气候友好型熟料也被表征，其中贝利特结晶度的可变性被怀疑。这些是基于贝利特钙-硫铝酸盐-铁钠石（BCT）和贝利特铁钠石（BYF）的熟料，尚未通过EBSD-EDX进行表征。Alit：在项目的第一部分，耦合EBSD-EDX分析已经成功用于表征各种阿利特变体的化学-晶体学组成（相分数、化学组成和晶体尺寸）。利用新的EBSD照相机，系统地研究了杂质离子对阿利特的精细结构和性能的影响。铝酸钙（C3 A）和α-铁素体相（C4 AF）：对于这些相，基本的化学晶体学分析迄今为止仅在有限的范围内是可能的。特别是，晶粒尺寸和化学组成的变化对相的反应性的影响仍然是有争议的讨论。在拟议的项目中，将优化所含C3 A和C4 AF相的高分辨率化学晶体学表征。特别是研究了水泥熟料中铁、镁和碱含量变化引起的C3 A和C4 AF相结构的变化。所有表征都将伴随着水化研究，以便将获得的数据与材料的反应性相关联。作为该项目的结果，结合EBSD-EDX熟料分析将具有实际应用价值，并将揭示熟料相组成、结晶度和反应性之间的基本关系。

In the previous project, the EBSD method for the characterization of cement clinkers was established. As described in the project report, the coupled EBSD-EDX analysis offers for the first time the possibility to characterize cement clinker in a spatial-resolved chemical-crystallographic manner. This means that for all clinker phases their fraction, chemical composition (including minor and trace element), crystallinity and crystallite sizes can be determined. For the first time crystallite sizes of the fine-grained clinker phases are accessible (1-10 μm).In the continuation of the project, the EBSD-EDX technology, previously successfully established in the cement sector, will be further developed to enable high-resolution, statistically safe analyzes of all clinker phases. A new, high-resolution EBSD camera is to be used for this purpose.Belit: In the previous project, it was found that the EBSD patterns of belite indicate low crystallinity, and that even when they are observed in idiomorphic crystal shape only very small crystalline areas can be detected. With the help of a more sensitive, high-resolution EBSD camera, the fine structure of the belite in Portland cement clinkers is to be analyzed in the follow-up project. In addition, alternative, climate-friendly clinkers are also to be characterized, in which a variability of the belite crystallinity is suspected. These are clinkers based on belite calcium-sulfo-aluminate-ternesite (BCT) and belite ye'elemit ferrite (BYF), which have not yet been characterized by EBSD-EDX.Alit: In the first part of the project, coupled EBSD-EDX analysis has already been successfully used to characterize the chemical-crystallographic composition (phase fraction, chemical composition, and crystal size) of various alite modifications. With the new EBSD camera, the influence of foreign ions on the fine structure and performance of alites is to be investigated systematically.Calcium aluminate (C3A) and - ferrite phases (C4AF): For these phases fundamental chemical-crystallographic analyzes have hitherto only been possible to a limited extent. In particular, the influence of the variation of the crystallite sizes and the chemical composition on the reactivity of the phases is still controversially discussed. In the proposed project, the high-resolution chemico-crystallographic characterization of C3A and C4AF phases contained will be optimized. Especially the structural changes of C3A and C4AF phases induced by variation in iron, magnesium and alkali content of cement clinker will be studied. All characterizations are to be accompanied by hydration studies in order to allow the correlation of the data obtained with the reactivity of the materials.As a result of the project, the coupled EBSD-EDX clinker analysis will be practical applicable and basic relations between clinker phase composition, crystallinity and reactivity will be revealed.