Influence of minor oxides on formation and decomposition of mineral calcium sulfoaluminate (3CaO·3Al_2O_3·CaSO_4)

摘要

In the forming process of the mineral 3CaO-3Al_2O_3·CaSO_4, transitional phase CA and C_(12)A_7 begin to form at about 900℃; CaF_2 and Fe_2O_3 can promote the forming of CA and C_(12)A_7; mineral 3CaO3Al_2O_3CaSO_4 largely forms at around 1150℃; and almost pure 3CaO-3Al_2O_3CaSO_4 is made along with the vanishing of the transitional phase CA and C_(12)A_7 at 1300℃. CaF_2 and Fe_2O_3 can promote the forming of the mineral 3CaO3Al_2O_3·CaSO_4, but TiO_2, ZnO and Cr_2O_3 can stabilise the phase CA and restrain the forming of 3CaO_3Al_2O_3·CaSO_4. At 1400℃, mineral 3CaO·3Al_2O_3·CaSO_4 decomposes, and Cr_2O_3, ZnO and CaF_2 promote the decomposition of 3CaO·3Al_2O_3·CaSO_4; and Cr_2O_3 and Fe_2O_3 can decrease the decomposition temperature of 3CaO·3Al_2O_3·CaSO_4.