In this study, desulfurization efficiencies of metallurgical dust (MD), ZnO, and Fe2O3 at neutrality, reduction, and oxidation atmospheres are studied and their sulfur capacities are calculated. Experimental results show that MD's sulfur capacity increases with increasing temperature within the tested range of 50 to 650degreesC at any atmosphere and approaches, even equals, the theoretical value when the temperature is higher than 500degreesC. Reduction and oxidation atmospheres have various degrees of negative effect on MDs, exerting its desulfurization ability at a temperature range of higher than 350degreesC; this means that MD is more effective at neutral atmosphere. Breakthrough curves of ZnO and Fe2O3 are similar to those of MD, but the complexity of MD's composition determines that there is still some difference existing among them. However, comparison of absolute values of sulfur capacities of MD, ZnO, and Fe2O3 shows that it is definitely feasible to use MD as a sulfur absorbent in the FGD process.