Abstract: The carbide slag as a calcium-based waste was calcined and used to remove HCl. The effects of HCl removal reaction temperature, HCl volume fraction, particle size and calcination temperature on the dechlorination performance of carbide slag were examined in a calcination/chlorination reactor. The results show that the carbide slag has the highest chlorination conversion at 700 ℃, and has higher chlorination conversions than limestone at the temperature above 650 ℃. It indicates that the carbide slag has a better dechlorination performance at higher temperature. The chlorination conversion of carbide slag rises linearly with the increasing of HCl volume fraction. As the particle size increases, the chlorination conversion decreases slowly. The calcination temperature above 900 ℃ is adverse to the HCl removal by carbide slag. The calcined carbide slag possesses more pores in the range of 2~10 nm. And after chlorination, the volume and area of pores in 2~10 nm drop by 56.2% and 62.2%,respectively. The pores in 2~10 nm may be the dominating area for the calcined carbide slag to absorb HCl.