Abstract：The effects of P and Al mixture on crystal transformation and phase composition of pure C2S were investigated. The main mineral compositions and phase composition at equilibrium state for roasted samples of P2O5 and Al2O3 doped C2S were analyzed by X-ray diffractomete and FactSage thermodynamic analysis software. The study has found that doping of P2O5 can inhibit the transformation of C2S crystal from β-C2S to γ-C2S. When the doping mass fraction of P2O5 is higher than 0.5%, the inhibition effect is obvious. When Al2O3 is doped in C2S, Al3+ in Al2O3 replaces Si4+ in β-C2S to form oxygen atom vacancy, improve the activation energy of C2S. Aluminate can replace silicate tetrahedron to form low melting point material, improve the stability of C2S and reduce the melting point. Therefore, P and Al mixed with C2S can not only inhibit the volume expansion caused by transformation of C2S crystal form from β-C2S to γ-C2S, improve the stability of Portland cement, but also reduce the fusibility temperature of C2S, and save the firing cost of Portland cement.
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HAO Shuai, LUO Guo-ping, CHEN Yin-sheng, CHAI Yi-fan, SONG Wei, AN Sheng-li. Effect of P and Al mixture on crystal transformation of C2S[J]. China Metallurgy, 2022, 32(9): 126-133.
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2022, Vol. 32 
