Process for recovering and utilizing useful substances from molten metal produced during reduction treatment of steel slag

A process for recovering and utilizing useful substances from a molten metal containing Ti, Si, Mn, V, P, C and the balance essentially iron, which has been produced in the process of manufacturing a steel slag cement from a steel slag discharged from a top-blowing oxygen converter, as the molten metal recovered during a reduction treatment of said steel slag, which comprises the steps of:

• (1) oxidizing said molten metal in an acidic refining furnace lined with an acidic refractory to a primary oxidation treatment by blowing oxygen in contact with said molten metal to oxidize most of the Ti and Si contained in said molten metal into TiO.sub.2 and SiO.sub.2 which form a primary slag on the surface of said molten metal, and discharging said primary slag from said said acidic refining furnace to recover and utilize said primary slag as substitutes for iron sand for a blast furnace burden material;
• then
• (2) following said primary oxidation treatment and said primary slag discharge, oxidizing said molten metal in said acidic refining furnace to a secondary oxidation treatment by blowing additional oxygen in contact with said molten metal to oxidize most of the Mn and V contained in said molten metal into MnO and V.sub.2 O.sub.5, which then form a secondary slag on the surface of said molten metal, and discharging said secondary slag from said acidic refining furnace to recover and utilize said secondary slag as a raw material mainly comprising MnO for manufacturing ferromanganese, a raw material mainly comprising V.sub.2 O.sub.5 for manufacturing ferrovanadium, and a raw material for a phosphoric fertilizer;
• and then
• (3) following said secondary oxidation treatment and said second slag discharge, oxidizing said molten metal in a basic refining furnace lined with a basic refractory to a tertiary oxidation treatment while adding a slag forming agent by blowing oxygen in contact with said molten metal to oxidize most of the C, and P contained in said molten metal into P.sub.2 O.sub.5, which then forms a tertiary slag on the surface of said molten metal, and discharging said tertiary slag from said basic refining furnace to recover and utilize said tertiary slag as a Thomas phosphoric fertilizer or a raw material for manufacturing yellow phosphorus;
• and
• (4) finally obtaining the remaining molten metal as a low-phosphorus high-quality steel.