MnO2对硅酸三钙晶粒尺寸及晶型的影响

Influence of MnO2 on Crystal Grain Size and Polymorphisms of Tricalcium Silicate(C3S)

摘要:

以Ca(OH)2，SiO2化学纯为原料，分别掺入不同质量分数的MnO2，制备了不同晶型的硅酸三钙(C3S)，运用相图，XRD（X射线衍射），IR（红外光谱）及MDI jade5.0软件研究MnO2对C3S晶粒尺寸和晶型转变过程的影响.结果表明：MnO2的掺杂降低了C2S及液相的形成温度，进而促使C3S生成.经MnO2掺杂后，C3S晶型转变和晶粒成长均受到影响.随着MnO2掺量的增大，CaO SiO2二元体系中C3S成核速率大于长大速率，导致C3S晶粒尺寸依次减小.同时，由晶面指数和IR分析发现，C3S晶型逐步由TⅢ型向R型转换，当w(MnO2)＜3.0%时，易稳定M型C3S存在，当w(MnO2)≥3.0%时，可稳定R型C3S存在.

Abstract:

Tricalcium silicate(C3S) with different polymorphism were prepared by a calcination method with Ca(OH)2 and SiO2 as raw materials and MnO2 as doping agent. The influences of MnO2 on grains growth and polymorphism transformation of C3S were investigated by phase diagram analysis, XRD, IR and MDI jade5.0 software. The results indicate that from the TGA and phase diagram analyses, the doping of MnO2 will reduce the formation temperature of C2S and liquid phase, resulting in promoting the formation of C3S. The crystal grain size and polymorphisms of C3S are influenced by the addition of MnO2. Crystal grain size of the C3S samples decreases by increasing the doping of MnO2, due to nucleation rate rather than growth rate of C3S in the CaO SiO2 binary system. The results from crystal plane index and IR demonstrate that polymorphism was transformed from TⅢ to R mode due to the addition of MnO2. M mode C3S exists in stable state at w(MnO2)＜3.0%, R mode C3S exists in stable state at w(MnO2)≥3.0%.