DESILICONIZATION AND DEPHOSPHORIZATION METHOD OF HOT METAL IN CONVERTER-TYPE REFINING VESSEL

• Main Author: OTANI SHINYA
• Format: Patent
• Language: English; Japanese
• Published: 16.04.2024
• 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

To provide desiliconization and dephosphorization methods of hot metal in converter-type refining vessels capable of improving yield by suppressing generation of CO gas and reducing slopping generation frequency.SOLUTION: In a method for dephosphorizing hot metal by blowing gaseous oxygen gas into hot metal 2 charged in a converter type refining vessel 1 of an upper bottom blowing system from an upper blowing lance 4 and by injecting an iron oxide source which is solid oxygen from the top, a desiliconization reaction rate constant of the solid oxygen is determined in advance using the stirring power density obtained from a flow rate of the bottom blowing gas, and an amount of gaseous oxygen required for the desiliconization treatment is calculated using the determined desiliconization reaction rate constant and the target concentration [Si] in the hot metal. The gaseous oxygen gas of the calculated amount of gaseous oxygen is blown in from the top blowing lance, and after the [Si] concentration in the hot metal during the desiliconization treatment reaches the target concentration [Si] in the hot metal, the process shifts from the desiliconization treatment to the dephosphorization treatment.SELECTED DRAWING: Figure 1 【課題】COガスの発生を抑制するとともにスロッピング発生頻度を低下させることで、歩留を向上させることができる転炉型精錬容器における溶銑の脱Si処理および脱りん処理方法を提供する。【解決手段】本発明は、上底吹き方式の転炉型精錬容器１に装入された溶銑２に対して上吹きランス４から気体酸素ガスを吹き込むとともに上方から固体酸素である酸化鉄源を投入して脱りん処理を行う溶銑の脱りん方法において、固体酸素の脱Si反応速度定数を底吹きガスの流量から得られる撹拌動力密度を用いて予め求めておき、求めた脱Si反応速度定数と目標となる溶銑中[Si]濃度とを用いて脱Si処理に必要な気体酸素量を算出し、算出した気体酸素量の気体酸素ガスを上吹きランスから吹き込み、脱Si処理中の溶銑中[Si]濃度が目標となる溶銑中[Si]濃度に到達した後に、脱Si処理から脱りん処理へ移行する。【選択図】図１