Ravaszová Simona, Dvořák Karel, Boháč Martin, Všianský Dalibor, Jančíková Andrea
Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00 Brno, Czech Republic.
Research Institute for Building Materials, Hněvkovského 30/65, 617 00 Brno, Czech Republic.
Materials (Basel). 2024 Feb 3;17(3):735. doi: 10.3390/ma17030735.
Tricalcium aluminate is an important phase of Portland clinker. In this paper, three polymorphs of CA were prepared by means of the solid-state synthesis method using intensive milling of the raw material mixture which was doped with various amounts of NaO and sintered at a temperature of 1300 °C for 2 h. The final products were evaluated through X-ray diffraction using Rietveld analysis. The effect of the Na dopant content on the change in the crystalline structure of tricalcium aluminate was studied. It was proven that the given preparation procedure, which differed from other studies, was close to the real conditions of the formation of Portland clinker, and it was possible to prepare a mixture of different polymorphs of calcium aluminate. Fundamental changes in the crystal structure occurred in the range of 3-4% Na, when the cubic structure changes to orthorhombic. At a dosage of Na dopant above 4%, the orthorhombic structure changes to a monoclinic structure. There are no clearly defined boundaries for the existence of individual CA phases; these phases arise at the same time and overlap each other in the areas of their formation at different Na doses.
铝酸三钙是波特兰水泥熟料的一个重要相。本文采用固态合成法，通过对掺杂不同量NaO的原料混合物进行强力研磨，并在1300℃下烧结2小时，制备了三种CA多晶型物。最终产物通过使用Rietveld分析的X射线衍射进行评估。研究了Na掺杂剂含量对铝酸三钙晶体结构变化的影响。结果表明，给定的制备过程与其他研究不同，接近波特兰水泥熟料形成的实际条件，并且可以制备不同多晶型的铝酸钙混合物。当立方结构转变为正交晶系时，晶体结构在3-4%Na的范围内发生了根本性变化。当Na掺杂剂的用量高于4%时，正交晶系结构转变为单斜晶系结构。各个CA相的存在没有明确的界限；这些相同时出现，并在不同Na剂量下它们形成的区域相互重叠。
