外来离子对硅酸三钙原位高温结构相变及性能的影响研究

我国水泥产量连续20多年稳居世界第一。硅酸三钙(C3S)的固溶体阿利特是硅酸盐水泥熟料的最主要胶凝相，粗略估算仅2012年C3S量就达11亿吨。不同晶型C3S胶凝性能存在差异，并显著影响熟料强度性能。因此，研究掺杂C3S相变过程及性能，对提高熟料性能，实现水泥工业节能减排具有重要意义。近来，申请人发现外来离子对C3S多晶态稳定作用依离子化学结构变化存在规律性，并推测离子对C3S相变过程影响同样存在规律性。但目前，离子对C3S相变过程影响尚不明确，且掺量达晶型转变点时C3S高活性现象，也尚未被理解。本项目针对传统研究方法的不足，采用本室拥有的18kW高温衍射仪结合Rietveld方法等，研究不同离子对结构相变的影响规律及机制，探讨离子固溶、结构相变，C3S晶体结构与性能间相互影响关系，确立获得高胶凝C3S的方法。研究成果有助于丰富水泥熟料化学应用基础理论，为提高水泥熟料强度性能提供理论基础。

The total amount of bulk cement in China has consecutively ranked first in the world over the past 20 years. The tricalcium silicate (C3S) solid solutions known as alites are the principle phase of clinker, responsible for strength development. The content of C3S is approximately to 110 million tons in 2012. Therefore, it is important to study the effect of foreign ions doping on the phase transition and property of C3S for the production of hydraulically favorable polymorphs. This is the key to improve the hydraulic property of clinker and realize energy conservation and emission reduction. In our recent study, the stabilization rule of different C3S polymorphs by the incorporation of foreign ions has been established. It is believed that some rule can also be extracted from the effect of foreign ions on the phase transitions. However, the effect of foreign ions on the phase transitions is unclear. Interestingly, maxima reactivity had been reported to be approached corresponding approximately to phase transitions point, which is also not fully understood. In view of the limitation of traditional research methods on experimental techniques and evaluation, in this project, the structural phase transition of C3S and its solid solutions will be studied by real time in-situ technique. The structural changes will be mainly monitored by the in-situ high temperature x-ray diffraction (18kW) we owned, and analysed using Rietveld method. An attempt will be made to study the regular effect of foreign ions on the phase transition and superstructure. The relationship between foreign ions doping,structural phase transition, polymorphism and the property of C3S will be discussed. The method to product hydraulically favorable polymorphs will be established. The results can enrich the basic theory of cement clinker chemistry, and lay a theoretical foundation for improving the quality control of Portland cement clinker production.