熟料和水泥水化产物中Mg^2+赋存状态显微分析

Microanalysis on Occurrence State of Mg^2+in Clinker and Cement Hydrates

采用光学显微镜、扫描电镜(SEM)、背散射电子图像(BSE)和X射线能谱分析(EDAX)观察和分析了Mg2+在熟料和水泥水化产物中的赋存状态.结果表明:在生长空间充裕的情况下熟料中的方镁石可形成八面体晶体,受生长空间限制可形成半自形晶或他形晶;熟料中方镁石晶粒尺寸主要分布在1.00~6.50μm,其中2.50~3.00μm晶体最多,最大粒径可达40.00μm;水泥水化后期,Mg(OH)2晶体沿c轴方向生长速度加快,颗粒厚度明显增加;固溶于熟料铝相中的MgO原位水化后形成Mg6Al2CO3(OH)16·4H2O;从熟料中引入的Mg2+可以与Ca2+、Si4+等离子形成水化硅酸钙镁或者吸附于水化硅酸钙表面.

Occurrence state of Mg^2+in clinker and hydrates was observed and analyzed with optical microscope,scanning electron microscopy(SEM),backscattered electron image(BSE)and energy dispersion X-ray analysis(EDAX).The results show that when the growth space is sufficient,the periclase forms octahedron structure,and subhedral or anhedral crystal is formed in limited space in clinker.Grain size of periclase in clinker is mainly in the range of 1.006.50μm,most of the grains size ranges from 2.50 to 3.00μm,and the length of the largest particle is up to 40.00μm.At the later stage of cement hydration,the growth rate of Mg(OH)2 crystal along the c-axis direction is accelerated and the particle thickness is increased notably.MgO dissolved in the clinker aluminum solid phase forms Mg6Al2CO3(OH)16·4H2O after in-situ hydration and carbonization.Mg^2+introduced from clinker can form magnesium calcium silicate hydrate with Ca^2+,Si^4+,etc.,or be absorbed on the surface of calcium silicate hydrate.