| 摘要 |
PURPOSE:To produce stably high-purity pig to be used as a raw material for a high-grade spheroidal graphite cast iron, etc. by oxidizing and removing Si and Mn in the molten pig in a preliminary treatment stage then adding an acid or the like and a flux thereto under mechanical stirring in succession to said oxidation and oxidation-refining elements such as P, S, etc. while suppressing decarburization. CONSTITUTION:Si, Mn, etc. in molten pig are oxidized and removed as a preliminary treatment by using a pan 2 to be used exclusively for said treatment of a KR-OB plant shown in the figure. O2 is charged from a lance 3 into the molten pig and a solid acid and flux (e.g.; >=1 kind among quicklime, CaCl2, etc.) are charged thereto from chutes 4,4 under stirring with an impeller in succession to the above-mentioned treatment and P, S and other elements which are liable to remove into basic slag are oxidation-refined while decarburization is suppressed. The high-purity pig contg., respectively by weight %, >4.0 T.C, <=0.09 Mn, <=0.09 P, <=0.005 S, <=0.009 Ti, <=0.005 As, and <=0.020 SIGMAT (total sum of Ti, Cr, V, As, and Sn) is thus obtd. |
