Sythesis And Research On Properties Of Nano-cement Clinker Minerals

Nano tricalcium silicate(C3S), dicalcium silicate(C2S), tricalcium aluminate(C3A) andtetracalcium aluminoferrite(C4AF) were synthesized via a combustion method with urea asfuel. The effects of stoichiometric ratio and ignition temperature on the content of f-CaO inthe synthesized samples were investigated. The phase composition，microstructure andparticle size distribution of samples were characterized by X-ray diffractometer(XRD)，Field emission scanning electron microscope (FESEM)，Zeta potential/submicron sizeanalyzer. And the hydration heat was tested by Digital display calorimeter. And themicrostructure of hydration products at different ages was observed by FESEM. Theeffects of naphthalene and polycarboxylate superplasticizer on the dispersing performanceof C3S and C2S were investigated by testing Zeta potential of dispersion system. And thecompressive strengths of the two minerals at different ages were tested.The content of f-CaO in synthesized samples decreased firstly and increasedsubsequently with the raise of stoichiometric ratio and ignition temperature. And thecontent of f-CaO in the sample reached the least value under the synthesized condition ofstoichiometric ratio at0.24(synthesing C3S),0.45(synthesing C2S with silica fume assilicon source),0.38(synthesing C2S with silica sol as silicon source),0.71(synthesingC3A and C4AF) and the ignition temperature at700℃.The average size of synthesized C3S and C2S with silica fume as silicon source were292nm and241nm, and the average size were226nm and177nm with silica fume assilicon source. And the value of synthesized C3A and C4AF were265nm and350nm.Synthesized four kinds of clinker minerals showed high hydration activity. During thehydration process of C3S, only one exothermic peak occurred. And during the process ofC2S, two exothermic peaks were tested, and the induction period was greatly reduced andthe second peak appeared early. And the compressive strengths at different ages of thesetwo kinds of minerals didn’t vary much and were lower than Portland cement.