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

在先前的项目中，建立了用于水泥熟料表征的EBSD方法。如项目报告所述，EBSD-EDX联用分析首次提供了以空间分辨化学结晶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组成、化学成分(包括微量和微量元素)、结晶度和微晶尺寸。细粒熟料相的微晶尺寸首次能够达到(1-10μm)。在该项目的继续进行中，先前在水泥行业成功建立的EBSD-EDX技术将得到进一步开发，以实现对所有熟料相的高分辨率、统计安全的分析。一种新的、高分辨率的EBSD相机将用于这一目的。目标：在之前的项目中，人们发现贝利特的EBSD图案表明结晶度较低，即使它们是在自形晶体形状下观察到的，也只能检测到非常小的结晶区。借助更灵敏、高分辨率的EBSD相机，波特兰水泥熟料中贝利特的精细结构将在后续项目中进行分析。此外，对气候友好的替代熟料也要进行表征，其中贝利特结晶度的可变性是可疑的。这些熟料是以贝利特硫铝酸钙(BCT)和贝利特发光铁氧体(BYF)为基础的熟料，还没有用EBSD-EDX进行表征。尽管：在项目的第一部分，EBSD-EDX耦合分析已经成功地用于表征各种阿利特改性的化学-晶体组成(相组成、化学成分和晶体尺寸)。利用新的EBSD相机，系统地研究了外来离子对阿利特精细结构和性能的影响。铝酸钙(C3A)和铁氧体相(C4AF)：到目前为止，对这些相的基本化学结晶学分析只能在有限的范围内进行。特别是，微晶尺寸和化学成分的变化对相的反应性的影响仍然是有争议的。在拟议的项目中，C3A和C4AF相的高分辨率化学结晶学表征将得到优化。重点研究了水泥熟料中铁、镁、碱含量变化对C3A和C4AF相结构的影响。所有的表征都将伴随着水化研究，以使获得的数据与材料的反应性相关联。作为该项目的结果，耦合的EBSD-EDX熟料分析将实际应用，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.