METHOD FOR DEPHOSPHORIZING MOLTEN IRON CONTAINING HIGH MANGANESE REDUCIBILITY

摘要

PURPOSE:To dephosphorize a molten iron with high manganese reducibility by adding a flux added with adequate ratios of CaO and CaF2 and specific ratios of manganese oxide and iron oxide to the molten iron after desiliconization and adding an adequate ratio of a carbonaceous material thereto while subjecting the molten iron to gaseous oxygen blowing. CONSTITUTION:The flux and oxidizing agent are added to the molten iron subjected to the desiliconization treatment and thereafter, the molten iron is dephosphorized by the gaseous oxygen blowing. CaF2 is added to the flux in the above-mentioned method at 30-70% of the weight of the CaO in the flux to adjust the basicity of the flux to 4-8. At the same time, 10-60% of the number of moles of total oxygen in the total oxygen source is supplied as the manganese oxide and 5-50% as the iron oxide to maintain the oxidizing powder of the flux. The balance of the total oxygen source is further subjected to the gaseous oxygen refining and the carbonaceous material such as carbon powder is added at a rate of 2-20kg per ton of the molten iron. The molten iron is thereby stably dephosphorized at a high level and the high manganese reduction and recovery rate is attained.