The conversion of high-sulfur iron ore to a quality product is important, since numerous Russian fields that are already operational or are planned for development (Lebedinsky, Kostomuksha, Toyozhnoye, Desovskoye, etc.) consist of skarn and quartzite with a high sulfide content. The optimal agglomeration method is usually pelletization, especially for sources that are far from steel mills. The induration of pellets permits their desulfurization by the transfer of sulfur to the gas phase (as SO2 and SO3), with subsequent capture of harmful components in the gas treatment department. In this technology, heating of the pellets by means of synthetic gas (syngas) derived from coal is of interest. The proposition considered in the present work is that the use of syngas instead of natural gas impairs pellet desulfurization. With a moderate sulfur content in the unfluxed material (no more than 0.3%), no significant difference in the desulfurization when using syngas and natural gas is seen, even though the gas entering the pellet bed contains 1–2% less oxygen (since the consumption and excess of air are lower). However, with a higher sulfur content in the initial material, the use of syngas rather than natural gas results in greater residual sulfur content in the final pellets. The use of syngas when the sulfur content in the ore is 0.5% leads to increase in the pellet’s sulfur content by 0.0028% and on fluxing by 0.0026% (in absolute terms). With decrease in productivity and increase in desulfurization time, the residual sulfur content in the pellets declines. However, in this case, heating by natural gas reduces the pellets’ sulfur content relative to syngas by 0.0048% and 0.0168% (again in absolute terms) for fluxed pellets. In terms of heat consumption, the use of syngas offers a small benefit: a relative decrease in unit heat consumption by 12 ± 3%. That is associated with the smaller air volume employed.
Bersenev et al. (Sun,) studied this question.