A molten steel refining method includes throwing a powder to molten steel while heating the powder with a flame formed by combustion of a hydrocarbon gas at the leading end of a top blowing lance. The lance height of the top blowing lance (the distance between the static bath surface of the molten steel and the leading end of the lance) is controlled to 1.0 to 7.0 m, and the dynamic pressure P of a jet flow ejected from the top blowing lance calculated from equation (1) below is controlled to 20.0 kPa or more and 100.0 kPa or less. P=.sub.g U.sup.2/2 . . . (1) wherein P is the dynamic pressure (kPa) of the jet flow at an exit of the top blowing lance, .sub.g the density (kg/Nm.sup.3) of the jet flow, and U the velocity (m/sec) of the jet flow at the exit of the top blowing lance.

A granulated material having an improved size distribution and a method and apparatus for the production of such a granular material where the grain size and grain size distribution is controlled by the use of a rotating distributor. The rotating distributor includes an upper inlet opening, sidewalls, a bottom and at least one row of openings at the lower end of the sidewalls. The openings in the sidewalls have a size of at least 5 mm in the smallest dimension.

A method that, regarding a process of refining molten iron, can increase the thermal margin and the amount of cold iron source to be used. A burner having jetting holes for jetting a fuel and a combustion supporting gas is provided at a leading end part of one lance that top-blows an oxidizing gas to molten iron contained in a converter-type vessel, or at a leading end part of another separate lance. A powdery auxiliary raw material or an auxiliary raw material processed into a powder form that is blown into the molten iron from the one lance or the other lance passes through a flame formed by the burner. This top-blowing lance for a converter is configured to secure a predetermined heating time and powder-fuel ratio. Also, a method for adding an auxiliary raw material and a method for refining of molten iron that use this top-blowing lance.

Provided is a dephosphorizing flux configured to adjust a phosphorous component contained in molten steel, the dephosphorizing flux includes a main material including BaCO.sub.3 and a supplementary material, wherein the supplementary material includes a first material containing either of NaHCO.sub.3 or Na.sub.2CO.sub.3 and a second material containing CaF.sub.2. Thus, in accordance with a dephosphorizing flux and a method for preparing the same of the present disclosure, the plugging of a lower blowing nozzle that blows a carrier gas during dephosphorization may be prevented while improving a dephosphorization ratio. In addition, since environment polluting substances are not used as in conventional arts, environment pollution risk may be reduced, and the cost burden due to the facility for pollution prevention and harmful substance management may be alleviated.

A sulfur additive is added to molten steel. At that time, the yield of sulfur in the molten steel is stabilized and nozzle blockage at the time of continuous casting due to impurities is prevented. A sulfur additive used for molten steel which contains iron sulfide ore particles with a particle size of 5.0 to 37.5 mm in 85 mass % or more with respect to the total mass % of the sulfur additive is used to produce Al deoxidized resulfurized steel containing S: 0.012 to 0.100 mass %.

The present invention relates to a particulate inoculant for treating liquid cast-iron, comprising, on the one hand, support particles made of a fusible material in the liquid cast-iron, and on the other hand, surface particles made of a material that promotes the germination and the growth of graphite, disposed and distributed in a discontinuous manner at the surface of the support particles, the surface particles presenting a grain size distribution such that their diameter d50 is smaller than or equal to one-tenth of the diameter d50 of the support particles.

A multiple chamber material-stirring lance and method used to treat molten metal in a ladle, the lance having a stirring gas chamber, and a plurality of gas permeable ports arranged at a terminal end of the gas chamber, and at least one material chamber positioned parallel to the gas chamber and terminating in a plurality of material ports. In use, the multiple chamber material-stirring lance is lowered into the ladle of molten metal, and gas and material are both introduced into a respective chamber and emitted through their respective ports. Stirring gas emitted through the gas permeable ports under a gas pressure between 40 and 600 cfm causes the stirring gas to create a boiling effect in the molten metal, drawing material into the stirring gas bubbles and away from the lance body, improving material dispersion efficiency and thus impurity extraction from the molten metal.

An electric furnace has a burner directed toward furnace contents. The burner includes a powder-feeding pipe, a jet hole for jetting a fuel, and a jet hole for jetting combustion-supporting gas. Hydrogen gas or a hydrogen-enriched gaseous fuel is jetted as the fuel to form a burner flame. An auxiliary material is jetted through the powder-feeding pipe so that the auxiliary material passes through an inside of the burner flame. According to a steelmaking method, an electric furnace has a burner that includes a jet hole for jetting a fuel and a jet hole for jetting combustion-supporting gas and that jets a flame through the jet holes toward an inside of the electric furnace. Hydrogen gas or a hydrogen-enriched gaseous fuel is used as the fuel of the burner, and an auxiliary material is blown in to pass through an inside of the flame formed by the burner.

A method for desulfurizing molten steel comprising taking a sample out from molten steel after tapping from a converter or during secondary refining and analyzing the sample rapidly with high accuracy by a method comprising a high frequency induction heating step wherein the sample is combusted and oxidized under the high frequency induction heating in an oxygen atmosphere having an oxygen purity of 99.5 vol % or more to convert S in the sample into SO.sub.2 and an analyzing step wherein SO.sub.2-containing gas produced in the high frequency induction heating step is analyzed through an ultraviolet fluorescence method to quantify S concentration of the sample.

A coaxial material-stirring lance (40) and method used to treat molten metal in a ladle, the lance having a stirring gas chamber (48), and a plurality of gas permeable ports (50 52) arranged as upper and lower port arrays along a length of the gas chamber, and at least one material chamber (43) positioned inside and coaxial with the gas chamber and terminating in at least one material ports (60). In another embodiment, a second material chamber is included inside the gas chamber, parallel to and immediately adjacent the material chamber. In use, the coaxial material-stirring lance is lowered into the ladle of molten metal, and gas and material are both introduced into a respective chamber. Gas mixes material through the molten metal, causing impurities to be removed from the metal.