加速碳化对水化硅酸钙显微结构的影响

发布时间：2018-02-03 14:41

  本文关键词： 水化硅酸钙 加速碳化 显微结构 核磁共振　出处：《硅酸盐学报》2015年08期 　论文类型：期刊论文

【摘要】：废弃水泥石等固体废弃物碳酸化不仅能够永久固碳,还可实现固体废弃物的再利用,减少对环境的污染。水化硅酸钙(C-S-H)是最主要的可碳化成分之一。合成了钙硅(C/S)比为1.50的C-S-H,研究了加速碳化对其显微结构的影响。用Rietveld全谱拟合的方法和热重-质谱联用的方法对碳化产物进行定量分析,用扫描电镜、N2吸附和29Si固体核磁共振对碳化前后的显微结构进行表征。结果表明:在99.9%CO2,0.2 MPa压力下加速碳化2 h之后,生成了3种不同晶型的碳酸钙和硅胶,碳酸钙从300℃开始分解,文石和球霰石具有较低的分解温度,结晶良好的方解石分解温度较高;多孔结构硅胶具有更高的吸附能力,但C-S-H碳化后的平均孔径从10.33 nm减小到6.69 nm,比表面积由85.6 m2/g减小到67.7 m2/g,这是由于大量的结构致密的碳酸钙晶体堆积造成的;C-S-H双层硅氧链之间的Ca O层逐渐脱去与CO2反应,硅氧四面体被质子化或与邻近的硅氧四面体链接,形成了聚合度更高的Q3和Q4结构。
[Abstract]:Carbonation of solid waste, such as waste cement stone, can not only sequester carbon permanently, but also realize the reuse of solid waste. In order to reduce the pollution to the environment, calcium silicate hydrate (C-S-H) is one of the most important carbonable components. C-S-H with a ratio of 1.50% of calcium to silicon (C / S) has been synthesized. The effect of accelerated carbonization on microstructure was studied. The carbonation products were quantitatively analyzed by Rietveld full-spectrum fitting and thermogravimetric mass spectrometry. The microstructure before and after carbonization was characterized by N2 adsorption and 29Si solid nuclear magnetic resonance. The results showed that the carbonization was accelerated at 99.9 and CO _ 2O _ 2 MPa pressure for 2 h. Three different crystal forms of calcium carbonate and silica gel were formed. Calcium carbonate began to decompose at 300 鈩，

本文编号：1487627