Evaporation Behavior of Components from CaO Treated EAF Dust under Wet Air Stream

摘要

For the recycling or stabilization of steelmaking dusts, the intermediate treatment process acts an essential role to recover zinc and other heavy metals together with the removal of halogens from the dust. The Waelz process is commonly employed worldwide. This process needs to heat the dust twice; first heating at 1200 for 6-8 hrs is to reduce zinc oxide in the dust and collect Zn in the fume, and second heating at 1200 for 2-4 hrs is to remove halogens and halides. Due to such inefficient process, many problems are pointed out from environmental aspects such as CO2 emission and large energy consumption. In order to improve large energy consumption in the Waelz process, the authors have proposed new process for dust treatment1,2) named as “Lime addition process”. In this process, ZnFe2O4 in the EAF dust can be converted to ZnO and Ca2Fe2O5 without carbothermic reduction at lower reaction temperature at 900 to 1100 with the faster reaction rate less than 3hrs3). In addition, steel industry can use Ca2Fe2O5 as a dephosphorization agent or raw material for sintering plant.