The synthetic CaO/Ca₃Al₂O₆ (prepared from carbide slag, aluminum nitrate enneahydrate, and glycerol water solution by combustion synthesis) as a CO₂ sorbent discharged from the CO₂ capture cycles using the calcium looping was used to remove HCl after a series of carbonation/calcination cycles. The effects of chlorination temperature, HCl concentration, presence of CO₂, and cycle number on the HCl absorption by the CaO/Ca₃Al₂O₆ sorbent after the repetitive carbonation/calcination cycles for CO₂ capture were discussed. In addition, the HCl absorption capacities of the CaO/Ca₃Al₂O₆ sorbent and the carbide slag were compared. The chlorination products of the CaO/Ca₃Al₂O₆ sorbent after 1 h HCl absorption are CaClOH, CaO, and Ca₃Al₂O₆ detected by XRD analysis. Among 600–800 °C, the CaO/Ca₃Al₂O₆ sorbent from the carbonation/calcination cycles achieves the highest HCl absorption capacity at 700 °C. The HCl absorption capacity of the cycled CaO/Ca₃Al₂O₆ sorbent rises as HCl concentration increases. CO₂ is adverse to the HCl absorption by the cycled CaO/Ca₃Al₂O₆ sorbent in the chlorination process. With the carbonation/calcination cycle number increasing from 0 to 50, the CaO/Ca₃Al₂O₆ sorbent after 5 cycles exhibits the highest HCl absorption capacity. HCl absorption capacities of the cycled CaO/Ca₃Al₂O₆ sorbent after 20 and 50 cycles were 0.18 and 0.13 g/g, which were 2.3 and 2.6 times as high as those of the cycled carbide slag after the same cycles, respectively.