The behavior of capturing sulphur by calcined calcium-based industrial wastes such as red mud and carbide slag was evaluated at fluidized bed boiler temperature and compared with that of limestone. The change of phase and microstructure for these materials during reaction was characterized. The results show that with increase of reaction time the calcium conversion is higher in red mud than in carbide slag

and that in limestone is the smallest under the same conditions. The optimum temperature for sulphur capture is 850－900℃ for red mud and 950－1000℃ for carbide slag. With increase of SO2 concentration the calcium conversion and the rate of sulfuration reaction for red mud increases for the same reaction time

and the effect of particle size on sulfur capture of red mud is not significant. Ca2SiO4 and Ca(OH2 are main calcium compounds in red mud and carbide slag

respectively. The range of pore size for calcined red mud and carbide slag is 5－20 nm that is the most favorable for sulfur capture

while that for calcined limestone is 45－420 nm. These calcium-based industrial wastes are of better performance of capturing sulfur at the fluidized bed boiler temperature because of their suitable pore structure.