The microstructure change in the dynamic calcination and sintering of carbide slag is studied at a high temperature of 1200℃ on a tubular electric furnace with X-ray powder diffractometer

mercury intrusion porosimeter and scanning electronic microscope(SEM). It is found that the main crystal composition of raw carbide slag

Ca (OH)2

turns to CaO after calcination at a high temperature. The mean pore diameter of carbide slag increases and the specific surface area decreases all along with increasing experimental time

while the total pore volume firstly increases and then decreases. After intense sintering

the surface of carbide slag is composed of many swelled dumbbell-like CaO particles

similar in particle diameters and arrayed in order.