On the decomposition of alite in portland cement clinker

摘要

The decomposition speed and mechanism of alite in Portland cement clinker are studied by means of op- tical microscopy, EPMA, XRD and chemical analysis. The results show that alite in portland cement clinker decompos- es at the maximum speed when the temperature is at 1025 ～1175 deg.c. It takes about 40 hours for the alite in clinker burnt in the rotary kiln to completely decompose at 1175 C, and about 68 hours for the alite burnt in RSP-kiln. The Presence of CaF_2 or CaSO_4 greatly affects the decomposi- Tion speed of alite. The former resists alite to decompose but The latter accelerates it and enables alite to decompose com- Pletely within 6 hours or less.