Treatment of Iron and Steelmaking Dust by Reducing Pellet Process

The mechanism of volatilization removing of Pb and Zn from electric furnace dust by reducing pellet process was clarified and the behavior of volatilization of Cl and F was studied. When the dust pellets without carbon were roasted in air or water vapor atmospher, Pb in the dust was changed to PbCl2 by coexisting NaCl and was volatilized above 90% at 1000°C. Pb compound, Pb (OH) Cl in the dust was decomposed to PbO and PbCl2 at lower temperature, then PbCl2 was removed. But, when NaCl content, was a little, sintering phenomena of the pellets by decomposition products PbO were observed and the fraction of volatilization of Pb was reduced at 1000°C. Cl-bearing compound was completely removed at 1100°Cin either roasting atmospher, but Zn was showed the fraction of volatilization of less than 20%. On the reducing treatment of pellets with carbon, Pb, Cl and Zn were entirely volatilized from the pellets above 1000°C. Iron contents in the pellets roasted above 1100°C were greater than 55% and it makes clear to use these pellets as iron ore.