| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for achieving a target S concentration in molten pig iron in the shortest treatment time, without excessively desulfurizing the molten pig iron. SOLUTION: The method for desulfurizing the molten pig iron achieves the target S concentration by using 3-7 kg/ton of a desulfurizing agent for 260-300 tons of the molten pig iron which is a target and contains 0.020-0.0050 mass% S, immersing an impeller having the diameter of 1,300-1,700 mm in the upper part of a blade into the molten pig iron, and rotating the immersed impeller at 120-140 rpm. The method includes adjusting a desulfurization treatment time t to be spent from the start of the rotation of the impeller by the end of the rotation, which is set at a range determined by substituting the diameter in the upper part of the blade of the impeller before the start of the desulfurization treatment for r in the expression of 23-0.01×r≤t≤27-0.01×r, in order to finish the desulfurization treatment. The desulfurization method can suppress the variation of the desulfurization rate, and can achieve the target S concentration in the molten pig iron in the shortest treatment time, without excessively desulfurizing the molten pig iron. COPYRIGHT: (C)2010,JPO&INPIT
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