Patent ID: 6506225
Filing Date: 2003-01-14
Classification: C21C

Abstract:
A process for desulfurizing sulfur containing iron melt and converting the desulfurized iron melt to a steel melt, comprising:(a) bringing a desulfurization slag of the following chemical analysis: SiO2 max. 20% by weight Al2O3 max. 50% by weight SiO2+Al2O3+TiO2=5-40% by weight FeO max. 2.0% by weight MnO max. 1.5% by weight CaO+MgO+BaO+Na2O+K2O=25-65% by weight MgO max. 20% by weight Na2O+K2O max. 10% by weight CaF2=0-60% by weight CaO+MgO+BaO+Na2O+K2O+CaF2=50-85% by weight CaO+MgOSiO2+0.5&it;â€ƒ&it;Al2&it;O3&it;min.â€ƒ&it;2Na2&it;O+K2&it;OSiO2&it;max.â€ƒ&it;1â€ƒto a temperature of 1400Â°-1800Â° C., (b) introducing the slag at said temperature along with a sulfur containing iron melt into a desulfurization vessel, the ratio of iron melt to desulfurization slag not exceeding 10:1 parts by weight, (c) separating the desulfurized iron melt from the desulfurization slag, (d) introducing said desulfurized iron melt into a steel making apparatus for producing a steel melt, (e) introducing the produced steel melt into a steel casting ladle together with a partial amount of the desulfurization slag from the desulfurization vessel, (f) discharging the steel melt from the steel casting ladle, and (g) introducing the slag of the steel casting ladle into said desulfurization vessel after the steel melt has been discharged.