Desulfurization and dephosphorization during self-reduction of high-basicity coal-bearing iron oxide briquettes

High-basicity coal-bearing iron oxide briquettes with a CaO/SiO₂ of 2.0 and a C/O molar ratio of 1.1 to 1.2, which were produced by BOF steelmaking sludge, BF dedusting ash and pyrite cinder, were self-reduced at temperatures from 1 330 ℃ to 1 380 ℃ to study the phenomena of desulfurization and dephosphorization.During the self-reduction, the desulfurization ratio by evaporating as COS is 20% to 40%.Residual sulphur is attached in slag and it can be separated from iron nuggets.The total desulfurization ratio is more than 97%.Excessive CaO in high-basicity coal-bearing iron oxide briquettes can restrain the reaction of phosphorous pentoxide reduced by carbon.The reduced phosphorous is partially absorbed by nascent metallic iron, and the other escapes from the briquettes.Phosphorous pentoxide attached in gangue which is not yet reduced can be separated from iron nuggets.The total dephosphorization ratio can reach up to 50% to 60%.It is indicated that clean iron nuggets with low sulphur and low phosphorous can be produced by self-reduction of high-basicity coal-bearing iron oxide briquettes