A new way to efficient utilization of eggshell waste: As green dephosphorization agent and accelerator for reduction roasting of high-phosphorus oolitic iron ore

Abstract

The cleaning and efficient disposal of eggshell waste presents many challenges. Reduction roasting of high-phosphorus oolitic iron ore (HPOIO) requires the addition of expensive alkali metal compounds to enhance dephosphorization. In this paper, the eggshell waste from the catering industry was used to replace traditional dephosphorization agents, which not only avoided environmental problems caused by mining, but also improved dephosphorization and iron extraction, and reduced production costs. Under suitable conditions, powdery reduced iron (PRI) comprising 93.04% iron and 0.09% phosphorus was produced. PRI is a premium steelmaking feedstock with 93.11% iron recovery. Mechanism research shows that an appropriate eggshell waste dosage inhibited the reduction of apatite in HPOIO, reacted with phosphorus in iron minerals to form apatite, and promoted the metallization of iron. Moreover, compared with blast furnace ironmaking, this process significantly reduced carbon emissions. It provides a new idea for the green utilization of eggshell waste.