Activity calculation for the components in CaO-Al2O3 and CaO-SiO2-Al2O3 slags

Calculation model for activities of the components in CaO-Al2O3 and CaO-SiO2-Al2O3 slags was established according to the molecule and ion coexistence theory. The activities of the components in CaO-Al2O3 and CaO-SiO2-Al2O3 slags were calculated, and the influence of w(CaO) on the activities of the components was discussed. The results show that when the w(CaO)in CaO-Al2O3 slag is less than 45%, with increasing the w(CaO), the activities of 3CaO·Al2O3 and 12CaO·7Al2O3 in slag increase, however, the activity of CaO·Al2O3 changes little. When the w(CaO)in CaO-Al2O3 slag is more than 45%, with increasing the w(CaO), the activities of CaO·Al2O3 and 12CaO·7Al2O3 in slag decrease, however, the activity of 3CaO·Al2O3 increases slightly. In the CaO-SiO2-Al2O3 slag, the activity of 12CaO·7Al2O3 is lower than that in the CaO-Al2O3 slag, with increasing the w(CaO), the activities of CaO and 3CaO·Al2O3 increase, and the activity of 2CaO·SiO2 decreases, however, the activity of CaO·Al2O3 increases at first and then decreases.