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

在之前的项目中，建立了水泥熟料的EBSD表征方法。正如项目报告中所述，EBSD-EDX耦合分析首次提供了以空间分辨的化学晶体学方式表征水泥熟料的可能性。这意味着对于所有熟料相，它们的分数、化学组成（包括微量元素和微量元素）、结晶度和结晶尺寸都可以确定。首次获得了细粒熟料相的晶粒尺寸（1 ~ 10 μm）。在该项目的后续工作中，EBSD-EDX技术将得到进一步发展，以实现对所有熟料阶段的高分辨率、统计安全分析。为此，将使用一种新的高分辨率EBSD相机。Belit：在之前的项目中，我们发现belite的EBSD模式表明结晶度较低，即使在自晶形态中观察到belite，也只能检测到非常小的结晶区域。在后续项目中，将借助更灵敏、高分辨率的EBSD相机，对波特兰水泥熟料中白石的精细结构进行分析。此外，还将对其他气候友好型熟料进行表征，其中怀疑白石结晶度的可变性。这些熟料是基于白石钙-亚硫铝酸盐（BCT）和白石铁素体（BYF）的熟料，尚未用EBSD-EDX进行表征。Alit：在项目的第一部分，耦合EBSD-EDX分析已经成功地用于表征各种alite改性的化学晶体组成（相分数、化学组成和晶体尺寸）。利用新型EBSD相机，系统地研究了外源离子对铝的精细结构和性能的影响。铝酸钙（C3A）和-铁氧体相（C4AF）：迄今为止，对这些相的基本化学晶体学分析只在有限的范围内可行。特别是晶体尺寸和化学成分的变化对相反应性的影响仍存在争议。在本项目中，将优化C3A和C4AF相的高分辨率化学晶体学表征。重点研究了水泥熟料中铁、镁、碱含量变化对C3A、C4AF相结构的影响。所有的表征都必须伴随着水化研究，以便使所获得的数据与材料的反应性相关联。通过该项目，EBSD-EDX耦合熟料分析将具有实际应用价值，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.