| 摘要 |
PURPOSE:To raise the yield of Mn as well as prevent the reversion of P from molten slag in the adjustment of the Mn content of the molten steel by a method in which a Mn oxide and a Fe-Si substance as a reducing agent are added to the molten steel and the basicity of slag formed is adjusted within a specific range. CONSTITUTION:In the addition of Mn to molten steel for adjusting the Mn content of the molten steel, a Mn oxide or a slag generated in the manufacture of a Fe-Mn substance is used as a Mn source. At the same time, a Fe-Si powder is added to the molten steel to reduce MnO2 and MnO present in the Mn ore and Fe-Mn slag. In this case, CaO is concurrently added to adjust the basicity[(CaO+MgO)/SiO2]of slag formed within a range of 1.8-4.0. Since MnO to combine with SiO2 in the slag is replaced with CaO and separated into a free state, the reduction of MnO to Mn by Si is effectively conducted to raise the yield of Mn. At the same time, P2O5 in the slag is fixed by CaO into a stable state in the slag to prevent the reversion of P into the molten steel. |
