| 摘要 |
PURPOSE:To produce molten low phosphorus iron under high Fe yield at low cost, by using slag having the specific composition at the time of producing molten iron by smelt-reducing iron ore in a top and bottom blowing converter. CONSTITUTION:In the converter 1 providing a top blowing lance 3 for blowing oxygen and bottom blowing nozzles 2 for blowing inert gas, the molten low phosphorus iron 4 produced at the previous operation is remaining by little quantity and iron raw material of iron ore, sintering ore, etc., coke for reducing agent and slag making material of lime stone, etc., are added. Oxygen gas is injected from the top blowing lance 3 and also inert gas of N2, etc., is blown from the bottom blowing nozzles 2, and the iron ore, etc., is reduced, to produce the molten iron. In this case, by adjusting the composition of generated molten slag 5 to 1.0-2.0 basicity and 10.0-18.0% Al2O3, 2.0-7.0% total Fe, P in the molten iron 4 is oxidized to P2O5 by FeO, etc., in the molten slag 5 and is dephosphorized as the stable compound with CaO, by basic slag and the molten low phosphorus iron 4 is stably produced at low cost.
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