| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a technique by which free lime in a slag produced by dephosphorization of molten iron in a converter is drastically reduced and the valuation of a byproduct is drastically improved. SOLUTION: The slag obtained after dephosphorization of the molten iron is adjusted to 0.5-2.0 basicity and 10-50 mass% t.Fe, and after tapping off the molten iron, oxygen is supplied to the slag from a bottom-blown tuyere 2. The free lime in the slag 4 after the supply of the oxygen is formed as calcium- ferrite and FeO, and good slag in which expansion caused by hydration does not occur even after cooling is formed. Furthermore, fluorine concentration in the slag before dephosphorization treatment is adjusted to <1 mass%, and after tapping off the molten iron, silica sand is added to the slag.</p> |
