METHOD OF REDUCING MANGANESE OXIDE IN CONVERTER

• Main Authors: IMOTO TAKEO, OGAWA YUJI
• Format: Patent
• Language: English; Japanese
• Published: 23.07.2015
• Subjects: CHEMISTRY; METALLURGY; METALLURGY OF IRON; PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OFWROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS

PROBLEM TO BE SOLVED: To reduce an amount of a used expensive alloy such as ferro-manganese in a secondary refining step, by efficiently conducting addition of manganese oxide for reducing the manganese oxide in a converter, when producing a molten steel from a molten iron having a carbon concentration of not less than 2.5 mass%, and a temperature of not greater than 1,400°C.SOLUTION: When conducting addition operation of a manganese oxide for reducing the manganese oxide during decarburization blowing in a converter, a proper operation condition for reducing the manganese oxide that a carbon concentration in molten iron is not less than 0.1 mass%, and a molten iron temperature is in a range of 1,500°C or more and less than 1,650°C, is secured for not less than 1 minute by decreasing an oxygen-feeding rate to add a large quantity of manganese to molten iron while avoiding production impediment such as high temperature blowing stop by extending a reaction time under a high reactivity condition in which mass transfer of CO gas dose not govern the reaction. 【課題】炭素濃度が2.5mass％以上で温度が1400℃以下の溶銑から溶鋼を製造する際に、転炉内での酸化マンガン還元添加を効率的に実施して、二次精錬工程におけるフェロマンガンなどの高価な合金使用量を削減する。【解決手段】転炉内の脱炭吹錬時のマンガン酸化物還元添加操業に際し、マンガン還元の適正操業条件である、溶鉄中炭素濃度 0.1mass%，溶鉄温度：1500〜1650℃未満にて、送酸速度を低下させ１分以上の適正条件を確保することによって、ＣＯガスの物質移動が反応に律側しない高反応性条件の反応時間延長によって高温吹止などの生産障害を回避しつつ多量のマンガンを溶鉄に添加する。【選択図】図１