DEPHOSPHORIZATION METHOD OF MOLTEN IRON

• Main Authors: SUGITANI TAKASHI, OTANI SHINYA, NAKASUGA TAKAMITSU
• Format: Patent
• Language: English; Japanese
• Published: 12.04.2018
• 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 provide a dephosphorization method of molten iron in a dephosphorization treatment using a converter type vessel, capable of improving both dephosphorization efficiency and iron yield.SOLUTION: The present invention provides a dephosphorization method of molten iron in which: a converter type vessel 1 is used and refining is performed while stirring the molten iron by blowing oxygen gas from a top blown lance 2, which is equipped at the tip with a Laval nozzle 4 having an outlet diameter De/throat diameter Dt of 1.40 to 1.70 and blowing also a bottom blown gas from the vessel bottom. An oxygen gas flow rate and a ratio of oxygen gas flow rate/bottom blown gas flow rate are kept respectively at predetermined values during desiliconization and dephosphorization periods.SELECTED DRAWING: Figure 1 【課題】転炉型容器を用いた脱りん処理における、脱りん効率と鉄歩留の向上を両立することができる溶銑の脱りん方法の提供。【解決手段】転炉型容器１を用い、出口径De/スロート径Dtが1.40〜1.70のラバールノズル４を先端に備えた上吹ランス２から酸素ガスを吹付け且つ底部から底吹ガスを吹込んで溶銑を攪拌しつつ吹錬を行う溶銑の脱りん方法において、脱珪期、脱りん期において酸素ガス流量、酸素ガス流量/底吹ガス流量比を各々所定の値とする。【選択図】図１