Effect of Adding Mode of Iron Oxide on Dephosphorization Behavior with the Recycling of Decarburization Slag

Abstract

The recycling of decarburization slag can considerably decrease the slag generation. However, the effect of recycling of decarburization slag, especially the adding mode of iron oxide on dephosphorization process has not been given more consideration. In this research, the effect of adding mode of iron oxide on dephosphorization behavior with the recycling of decarburization slag has been studied. The results indicate that the main phase of dephosphorization slag at different times under two adding modes is composed of FeO, 2CaO · SiO2, 2CaO · SiO2–3CaO · P2O5, Ca3Mg(SiO4)2, and Ca3Fe2O5. But, the content of each phase, especially FeO, 2CaO · SiO2, 2CaO · SiO2–3CaO · P2O5, varies greatly, and the dephosphorization behaviors are significantly different. In the case of initial lump‐sum addition of iron oxide (Pattern A), the dephosphorization is mainly completed in the first 5 min. On the other hand, the dephosphorization is mainly completed from 5 to 10 min in the case of divided addition of iron oxide (Pattern B). The reason for this is the interfacial oxygen potential under the Pattern A is as high as about 1.64 × 10−11 atm, which is about two times higher than that of the Pattern B. And the slag formation path is significantly different between the two adding modes.