(p462) Briquetting and High Temperature Properties of Self-reducing Pellets Containing EAF Dust

摘要

Electric arc furnace dust with a micron particle size is harmful to the environment. In the pyrometallurgical EAF dusttreatment process, the lead and zinc are separated as a crude zinc oxide while the iron is generally reduced tometallic iron. The effect of the briquetting parameters on the green pellet strength was investigated in this paper. Inaddition, Effects of reduction temperature, reduction time and C/O molar ratio on metallization rate of iron oxides,and removal rate of element Zn were checked respectively. The results show that: Effect of different factors on thedrop number is greater than the compressive strength of briquettes. Green ball drop number is more sensitive tomoisture content and bentonite content. The parameters of briquetting for pretreating the EAF dust are optimizedas follows: 8~10% water, 1~2% bentonite, 70 MPa pressure, and C/O molar ratio 1.0~1.1. The drop number of thegreen pellets increases from 1.4 times to 6.4 times by water changed from 4% to 10%, while it drops from 8.2 timesto 3.0 times when the adjunction of 3% bentonite is cancelled. Pyrometallurgical processing of EAF dust withcarbon pellets is fast and effective. After crushing and magnetic separation, metallic iron could be returned to EAF.The iron phases are mainly metallic iron, calcium ferrite and a small amount of ferrous oxide after high temperaturereduction. When reduction temperature, reduction time, C/O molar ratio are 1200 °C, 20 min and 1.1 respectively,direct reduction iron is most concentrated.