METHOD OF TREATMENT OF STEEL IN LADLE Russian patent published in 2003 - IPC

FIELD: metallurgy; treatment of steel in ladle. SUBSTANCE: proposed method includes tapping of steel from steel-making unit, delivery of de-oxidizing agents and slag-forming materials, blowing ladle through oxygen lance , measurement of steel temperature, drawing steel and slag samples. In the course of tapping steel into ladle, aluminum pigs are delivered to ladle at rate of 1.8-2.4 kg/t of steel. After tapping, steel is blown through bottom with argon at flow rate of 0.057-0.115 cu mg/h.t of steel in the course of entire period of treatment, slag surface is blown with oxygen through lance at flow rate of 0.014-0.140 cu mg/min/t of steel. Lance is placed at distance equal to 0.1-30 calibers of lance nozzle from surface of slag. Then, thickness of layer of slag and its amount are determined, after which surface of slag is blown with powder-like calcium-containing material in jet of inert gas at flow rate of 0.03-0.14 cu m/h.t of steel through lance which is placed distance from slag surface equal to 0.1-25 calibers of lance nozzle. Then, wire with filler in form of calcium-containing powder material is fed to ladle; this material contains pure calcium in the amount of 20-60 mass-%. Consumption of calcium-containing material is set within 6-10 kg/t of slag in terms of pure calcium. Consumption of wire is set within 0.18-0.54 kg/t of steel in terms of pure calcium. EFFECT: enhanced efficiency of desulfurization of steel . 3 cl, 1 tbl