中文摘要：

硅酸三钙（C3S）是硅酸盐水泥和阿利特硫铝酸盐水泥熟料中重要的矿物之一.为研究C3S的特性和性能,使用CaSO4和CaF2作为矿化剂,分别在1 350、1 400和1 450℃合成了高纯度的C3S.1 350℃得到的C3S纯度高于95％,而在1 400和1 450℃合成的C3S纯度高于97％.检测结果显示3个不同温度下合成的C3S的游离氧化钙含量均小于1％.样品的化学成分分析表明,1 400和1 450℃合成的C3S中仅有痕量的SO3存在,合成过程中几乎所有的CaSO4均分解为CaO,并且与部分SiO2形成了C3S.对所有样品的X射线衍射分析结果显示,合成的C3S为M1与（或）M3型.扫描电子显微镜分析结果显示,不同温度下合成的C3S的微结构有所不同.通过差热分析对矿化剂作用下的C3S合成过程进行了分析,结果表明该合成方法与通常的C2 S和CaO通过固相反应合成C3S之间存在显著差异,是一个两步合成过程.

英文摘要：

The tricalcium silicate （C3S） phase exists in both ordinary Portland cement （OPC） and alite sulphaluminate cement clinkers.It is necessary to synthesize the pure C3 S for the investigation of the characteristics and performance.Mineralizers like CaF2 and CaSO4 can be used to reduce the sintering temperature in the synthesis of pure C3 S.A high purity of C3 S was synthesized at different temperatures （i.e.,1 350,1 400 and 1 450 ℃.The C3S samples synthesized are PC3S-1 350,PC3S-1 400and PC3S-1 450,respectively.）.The purity of C3S is ＞95％ for sample PC3-1350,and ＞97％ for samples PC3S-1400 and PC3S-1450.The free limes in all the samples were determined to be ＜ 1％.The chemical analysis shows that there is only trace SO3 in the samples PC3S-1400 and PC3S-1450,indicating that almost all CaSO4 is decomposed into CaO to form C3S with a part of SiO2.All the samples were characterized by X-ray diffraction and scanning electron microscopy.The XRD results indicate the presence of monoclinic M1 and/or M3 type C3S polymorph in all the samples.The SEM images show that the microstructures of the samples sintered at different temperatures are varying.The formation process of pure C3 S with the mineralizers was investigated by differential thermal analysis,indicating that the process differs from the formation process of C3 S via the solid reactions between C2S and CaO.