Synergistic Effect of C12A7 and CA on Alumina Leaching Property Under Low Calcium/Aluminum Ratio

High calcium/aluminum ratio (C/A=12:7) is one of the main problems which inhibit the development of lime sinter process. Decrease the C/A of clinker is studied in this paper. 12CaO•7Al2O3 (C12A7) and CaO•Al2O3 (CA) were synthesized at 1350 °C by analytical pure reagents. The phase composition of sinters was analyzed by XRD and the alumina leaching experiments were carried out. The results show that the optimal alumina leaching ratio of C12A7 and CA are 93.40% and 73.18%. The leaching experiments of the mixture of C12A7 and CA with different proportions were carried out. The alumina leaching ratio of the mixture reaches 91.12% when the content of C12A7 is 40% (in mass). Above this proportion, the alumina leaching ratio increases little. The results show that the existence of C12A7 can promote the leaching property of CA.