| 摘要 |
PURPOSE:To remove P and S inexpensively and effectively and to produce molten iron contg. low P and S by blowing powder fluxes consisting essentially of CaO to molten iron contg. low Si and performing dephosphorization which is oxidation reaction and desulfurization which is reduction reaction separately. CONSTITUTION:Powder fluxes consisting essentially of CaO are first blown together with gaseous oxygen to low Si molten iron of <=0.10% Si obtd. by a preliminary desulfurization, whereby the molten iron is subjected to refining consisting essentially of dephosphorization. The fluxes are blown together with inert gases in succession, whereby the molten iron is subjected to refining consisting essentially of desufurization. In the stage of refining consisting essentially of said dephosphorization, a flux compounded by controlling the content of fluxes such as CaF2 to <=5-50% is used in the refining stage consisting essentially of said dephosphorization and a flux compounded with <=30% solvents is preferably used in the refining stage consisting essentially of desulfurization. The preferable grain sizes of said fluxes are about 0.01-0.3mm. and the depth at which a lance for blowing the fluxes is immersed is preferably about >=1m. |
