Abstract: An immersion nozzle which comprises a twisted tape-shaped part (1) for allowing a flow of molten steel to swirl in the nozzle. This part is applicable to both of straight pipe type and double port type immersion nozzles, and a double port type immersion nozzle (12) is constructed to be bottomless to eliminate a problem associated with inclusions that may attached to bottom surface. Further, in the immersion nozzle, an inner wall surface of a discharge port is shaped to be arcuately divergent in longitudinal cross section, whereby the quality of cast pieces are further enhanced. When the immersion nozzle additionally includes a construction (15) for blowing a gas into a flow of molten steel which is made by the twisted tape-shaped part to swirl, effects of catching, carrying and floating inclusions are further enhanced.

Abstract: In a process for the gasification of solid carbonaceous material such as coal, powdered coal is top-blown onto a molten iron bath stored in a furnace through a non-submerged lance toward a hot spot formed by means of a jet of oxygen and steam top-blown through a non-submerged lance, coal being blown by means of a carrier gas, and flux is optionally added into the furnace by the lump or blown toward the hot spot, thereby the coal being gasified. The ratio L/L.sub.o of the depression depth L of the molten iron bath to the molten iron bath depth L.sub.o is maintained from 0.05 to 0.15, and the blowing velocity of the solid carbonaceous material is maintained from 50 to 300 m/sec so as to suppress the forming of an adhered mass in the furnace. A stirring gas is blown through a bottom nozzle to stir the molten iron bath.

Abstract: A process for making carbon steel and low-alloy steel in a basic oxygen furnace is disclosed, which comprises preparing a molten metal suitable for producing the steel in said basic oxygen furnace, carrying out the top-blowing of oxygen gas and bottom-blowing of carbon dioxide gas and then tapping the resulting molten steel. The top-blowing oxygen gas is injected through a lance onto the molten metal at an outlet velocity of Mach 0.8-2.0.

Abstract: A method of producing carbon steel and low-alloy steel in a basic oxygen furnace is disclosed, in which a blow of the bottom-blowing gas predominantly comprised of carbon dioxide is introduced into a molten metal through at least one nozzle provided in the bottom or side wall of said basic oxygen furnace at least partly during the period of time from the beginning of blowing to the tapping of the melt, and the flow rate of the bottom-blowing gas is 1/200 - 9/100 the rate of oxygen impinged upon the melt through a lance.

Abstract: In the treating of waste slags produced in the desulfurization and/or dephosphorization of molten pig iron with alkali carbonates, the alkali is recovered by extracting said waste slags with hot water while feeding carbon dioxide gas to form an extraction solution having a pH of 9.0-11.5 and recovering alkali carbonates from said extraction solution. The extraction solution contains little sulphur and silicates, from which alkali carbonates can be easily recovered with high yield therefrom.

Abstract: In an automatic molding apparatus, a Doppler speed meter is used to detect the rising speed of molten metal within a mold, and a nozzle stopper attached to a ladle in which the molten metal is contained is actuated in response to a difference between a detected speed signal and a speed pattern signal to control the opening of the nozzle of the ladle whereby the rising speed of the molten metal fed from the ladle to the mold through the nozzle can be controlled in accordance with an optimum molding velocity pattern.