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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 ℃, and the cosolvents are propyl alcohol (NPA) and H2O, the catalyst is HNO3. This sol-gel is burned for 12 hat 1 350-1 450 ℃ 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.
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 hat 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 the 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.