To recover a valuable metal in a molten steel at a small energy cost by adding a stainless steel scale and an A1 dross in the case of melting the steel, and recovering the valuable metal in the stainless steel scale while utilizing the heat generation caused by the thermit reaction of the A1 dross.
Valuable metal oxides (NiO, Fe3O3, Cr2O3) in a stainless steel scale are reacted with A1 in the slag or in the molten steel and recovered in a metal, and A1 of the stoichiometric quantity is consumed. The recovery ratio of Cr is increased by keeping the alkalinity of the slag at a specified value. The slag alkalinity is 0.8-1.5, preferably 0.9-1.1. The addition of the stainless steel scale and the A1 dross is, by weight, ≤5% of the total charge of the iron source, preferably ≤2.5%. The ratio A1/A1* is ≥0.7, preferably ≥1.0 when the A1 quantity necessary for stoichiometrically reducing the valuable metallic oxides contained in the stainless steel scales is defined as A1*.
HONJO NORIO
TSUNO MASAHIDE
ARAGAI HAJIME
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