Enhanced hydrodesulphurization of cokes deposited on iron ore by air gasification

The influence on air-gasification of cokes deposited on iron ores were studied in under successive desulphurization at 750 °C under atmospheric hydrogen. Gasification promoted by steam (water: 40 μl min^-1) at 350 °C for 125 min gasified 21% of the coke and allowed 25% oxidative desulphurization (based on sulphur in the coke) during the gasification and enhanced the successive hydrodesulphurization level up to 63% giving a total desulphurization of 88%. This level is comparable with that achieved after grinding. Gasification at higher temperatures, which burned more coke, was less effective in enhancing hydrosedulphurization. Gasification increases the access of hydrogen molecules to sulphur atoms in the coke. Gasification, which increases the surface area of the coke and removes the sulphur preferentially, is discussed in terms of reactivity.