The Pyrolysis Behavior of Ferrous Sulfide Under CO-H 2 Mixed Atmosphere

The pyrolysis behavior of FeS in the blast furnace process is of vital importance to control the gaseous sulfide species and emissions of the blast furnace gas and the sulfur content in the molten iron. This work presents an experimental study on the pyrolysis behavior of FeS under CO-H 2 atmosphere from 200 °C to 900 °C by thermal-gravimetric and mass spectrometry (TG-MS). Besides, thermodynamic theoretical calculations were conducted to further understand the pyrolysis process. The results showed that only trace amounts of FeS was reduced to elemental Fe in any CO-H 2 atmospheres studied. H 2 S and COS were the main gaseous sulfides generated by the pyrolysis reactions of FeS in CO-H 2 atmosphere. Increasing the proportion of H 2 in the reducing atmosphere reduced the pyrolysis reaction temperature of FeS, which was beneficial to the decomposition of total sulfides and promoted the conversion of sulfides to H 2 S. On the other hand, CO promoted the conversion of sulfides to COS. The appearance order of the gas product as increasing the temperature under the strong reducing atmosphere (CO-H 2 ) was by H 2 S → COS → CS 2 → S 2 → S.