硫铝酸钙在低铁水泥熟料中的二次形成

Secondary formation of C_4A_3$ in low iron cement clinker

主要研究硫铝酸钙(C_4A_3$)在低铁水泥熟料中的二次形成过程,以找到最佳配方及烧成制度,使得硫铝酸钙在低铁水泥体系中得以共存。利用X线衍射(XRD)结合Rietveld定量方法和热重-差示扫描量热(TG-DSC)分析,研究了SO_3含量、烧成制度对硫铝酸钙形成的影响,以及熟料中各物相的形成过程。结果表明:在低铁情况下,C_3S较难形成。由于一次烧成过程中硫的损失以及自身中间相含量低,难以结合硫,故不易形成C_4A_3$。而熟料掺CaSO_4后进行二次热处理可获较好的效果。研究发现硫铝酸钙在低铁水泥体系中的形成温度区间为1 050~1 270℃,温度继续升高将会迅速分解,最佳处理制度是1 250℃保温处理1 h。

In order to obtain the best formulations and sintering process for 3CaO·3Al2O3·CaSO4（ C4A3$） reformation,the reformation process of C4A3$ in the cement clinker with low iron content was explored.The influence of SO3 content and sintering process on the formation of C4A3$,and the evolution of the formation of clinker phases were examined using X-ray diffraction（ XRD） Rietveld quantitative methods and differential scanning calorimetry and thermo-gravimetric（ DSC-TG） analysis.Results showed that in the case of low iron clinker firing,it was difficult to form 3CaO·SiO2（ C3S）.Because of the loss of SO3 during the sintering and few amount of interstitial phases,it was difficult to form C4A3$.But the approach which clinker doped with S with a secondary heat treatment had a good effect.The formation temperature of C4A3$ in the low iron cement was about 1 050-1 270 ℃,beyond which it would rapidly decompose.The best firing system was annealed at 1 250 ℃ for 1 h.