Synthesis of C₃S by sol-gel technique and its features

Abstract

Sol-gel method is a technique to synthesize inorganic materials based on wet-chemical reaction theory. The results have shown that reactants tetraethyl orthosilicate (TEOS) and Ca(NO₃)₂·4H₂O can form sol and gel in solution at 50–60 °C, and the cosolvents are propyl alcohol (NPA) and H₂O, the catalyst is HNO₃. This sol-gel is burned for 12 h at 1 350–1 450 °C so that the organic matter, free water (moisture) in sol-gel system are removed and a solid reaction has taken place to form the resulting product. The product has been confirmed to be C₃S by XRD, SEM and ²⁹Si MAS NMR, as well as free lime content of the product which is less than 0.2% was determined by propanetriol-ethanol-method. The analysis determined by EDXA has indicated that the n(Ca)/n(Si) ratio in corresponding to micro-region is close to theoretical value of 3:1. This resulting product is C₃S with Si sites of Q⁰ polymerization, and has higher purity and hydraulic activities at earlier age of hydration.

Keywords

sol-gel technique / synthesization / purity / tricalcium silicate / morphology / ²⁹Si MAS NMR

References

[1] Taylor H. F. W. Cement Chemistry[M], 1997 Second Edition London Thoma Telford Services Ltd. 1-13.

[2] bensted J., Barnes P. Structure and Performance of Cements [M], 2002 Second Edition London and New York Spon Press 57-73.

[3] Stephan D., Maleki H., Knofel D., . Influence of Cr, Ni, and Zn on the Properties of Pure Clinker Phases Part I C3S [J]. Cement and Concrete Research, 1999, 29: 545-552.

[4] Haoxuan L., Agrawal D. K., Jiping C. Formation and Hydration of C3S Prepared by Microwave and Conventional Sintering[J]. Cement and Concrete Research, 1999, 29: 1 611-1 617.

[5] Lu Z., Xu X., Xiao Xiangqi. Effect of Grain Size of CaCO₃ and SiO₂ on The Formation of C₃S under Different Conditions[J]. Journal of Wuhan University of Technology-Mater. Sci. Ed., 2007, 22(3): 533-536.

[6] Yang N., Yu Guiyu. Brief Summary of Sol-gel Method, Part I, Basic Priciple and Processes of Sol-gel Method[J]. Bulletin of the Chinese Ceramic Society, 1992, 2: 56-63.

[7] Chen H., Wang Peiming. Preparation of C₂S Powders by Sol-gel Method[J]. Materials Science & Engineering, 2000, 7(18): 53-56.

[8] Feng Xiuping. Early Hydration of β-C₂S Synthesized by Sol-gel Technique[J]. Journal of Hohai University, 2000, 3(28): 82-85.

[9] Gu Y., Gu H., Xu H., . Semi-empirical Studies on Hydrolysis Process of TEOS[J]. Chinese Journal of Inorganic Chemistry, 2003, 12(19): 1 301-1 306.

[10] Huo Y., Zhai Y., Tong Huanan. Influence of Three Cosolvents on Hydrolysis Tetraethyl-orthosilicate[J]. Journal of Northeastern University-Natrue Science Ed., 2004, 2(25): 133-135.

[11] Lippmaa E., Magi Samoson A., . Structural Studies of Silicates by Solid-state Higher Resolution ²⁹Si NMR[J]. J. Am. Chem. Soc., 1980, 102: 4 889-4 893.

[12] Grimmer R. Colombet P., Grimmer A.-R. Structural Investigation of Calcium Silicates from 29Si Chemical Shift Measurements[M], 1994 London Application of NMR Spectroscopy to Cement Science, Gordon and Breach 113-151.

[13] Hamid S. A. The Crystal Structure of the 11 &OA Natural Tobermorite[ J]. Zeit Kristall., 1981, 154: 189-198.

[14] Tsuji M., komarneni S., Malla P. Substituted Tobermorite: ²⁷Al and ²⁹Si MAS NMR, Cation Exchange, and Water Sorption Studies[J]. J. Am. Cer. Soc., 1991, 74: 274-279.

[15] Taylor H. F. W. Tobermorite, Jennite, and Cement Gel[J]. Zeit. Kristall., 1992, 202: 41-50.