Proposed is a molten iron refining method capable of securing an in-flame staying time period of a heat transfer medium without being influenced by height adjustments of a blowing-purpose oxygen-blowing lance. As far as to a position lower than an upper end inside a converter-type vessel 1, a blowing-purpose oxygen-blowing lance 3 that supplies oxidizing gas and is capable of ascending and descending and at least one burner lance 4 capable of ascending and descending independently of the blowing-purpose oxygen-blowing lance are inserted. From the blowing-purpose oxygen-blowing lance, either oxidizing gas or oxidizing gas and CaO-containing refining agent are blown onto the molten iron. Also, a flame is formed by causing the burner lance to discharge fuel gas and combustion supporting gas. Powder particles discharged from the burner lance are caused to pass through the flame and to be blown onto the molten iron in a heat-transferred state, so that the molten iron is thermally compensated.

A molten metal component estimation device including: an input device configured to receive measurement information about a refining facility including measurement results regarding an optical characteristic; a model database that stores model expressions and model parameters, regarding a blowing process reaction, including a model expression and model parameters representing a relation between the oxygen efficiency in decarburization and a carbon concentration in a molten metal in the refining facility; and a processor configured to: estimate component concentrations of the molten metal including the carbon concentration in the molten metal by using the measurement information, the model expressions and the model parameters; estimate the carbon concentration in the molten metal based on the measurement results; and determine the model expression and the model parameters to be used when estimating the component concentrations of the molten metal, based on the estimation result of the carbon concentration in the molten metal.

A top-blowing lance nozzle is configured to freely switch an adequate expansion condition so as to control an oxygen-blowing amount and a jetting velocity independently of each other without requiring a plurality of lance nozzles or a mechanically movable part. A lance nozzle is configured to blow refining oxygen to molten iron charged in a reaction vessel while a gas is blown from a top-blowing lance to the molten iron. One or more blowing holes for blowing a working gas are on an inner wall side surface of the nozzle, at a site where the lance nozzle has a minimum cross-sectional area in a nozzle axis direction or at a neighboring site of the site.

When supplying oxygen source to molten pig iron inside a converter-type refining furnace and performing desiliconization, dephosphorization, and decarburization refining, one or more of slag removal flow shape, slag removal flow velocity, and slag surface shape while discharging slag through a throat is measured to estimate one or both of a slag removal amount and physical properties of removed slag. When sequentially performing one or both of desiliconization and dephosphorization, an intermediate step of discharging part or all of generated slag through the throat, and the remaining other refining step, in the intermediate step, the method measures one or two of slag removal flow shape, slag removal flow velocity, and slag surface shape, estimates one or both of amount and physical properties of slag removed, estimates remaining slag amount, or remaining slag amount and composition, and determines an auxiliary raw material amount to be fed in the other refining step.

When supplying oxygen source to molten pig iron inside a converter-type refining furnace and performing desiliconization, dephosphorization, and decarburization refining, one or more of slag removal flow shape, slag removal flow velocity, and slag surface shape while discharging slag through a throat is measured to estimate one or both of a slag removal amount and physical properties of removed slag. When sequentially performing one or both of desiliconization and dephosphorization, an intermediate step of discharging part or all of generated slag through the throat, and the remaining other refining step, in the intermediate step, the method measures one or two of slag removal flow shape, slag removal flow velocity, and slag surface shape, estimates one or both of amount and physical properties of slag removed, estimates remaining slag amount, or remaining slag amount and composition, and determines an auxiliary raw material amount to be fed in the other refining step.

A method for refining hot metal in a converter using a top-blowing lance having a refining powder supply channel, a combustion oxidizing gas supply channel, and a refining oxidizing gas supply channel that are separate from each other includes supplying at least one of a lime-based flux, iron oxide, and a combustible material as a refining powder from the refining powder supply channel to a surface of the hot metal using a fuel gas or a mixture of the fuel gas and an inert gas as a carrier gas while supplying a combustion oxidizing gas from the combustion oxidizing gas supply channel to form a flame below a leading end of the top-blowing lance, and supplying a refining oxidizing gas from the refining oxidizing gas supply channel to the surface of the hot metal.

A method for refining hot metal in a converter using a top-blowing lance having a refining powder supply channel, a combustion oxidizing gas supply channel, and a refining oxidizing gas supply channel that are separate from each other includes supplying at least one of a lime-based flux, iron oxide, and a combustible material as a refining powder from the refining powder supply channel to a surface of the hot metal using a fuel gas or a mixture of the fuel gas and an inert gas as a carrier gas while supplying a combustion oxidizing gas from the combustion oxidizing gas supply channel to form a flame below a leading end of the top-blowing lance, and supplying a refining oxidizing gas from the refining oxidizing gas supply channel to the surface of the hot metal.

A converter for the production of steel by a blowing process from a substantially liquid raw material, in particular pig iron, includes several injectors which are dispersed in the sidewall of the converter about the converter inner circumference and directed towards the bath level for refining the pig iron. The injectors are designed as supersonic nozzle, which are surrounded by a ring nozzle forming an enveloping gas jet. The injectors are oriented at an angle of max. 43 in relation to the bath surface, with oxygen being introduced through the supersonic nozzle and a mixture of compressed air and natural gas being introduced through the ring nozzle. The jet pulse for the oxygen jet fed through the supersonic nozzle is dimensioned such that an infiltration of the oxygen jet into the melt bath is ensured.

A converter for the production of steel by a blowing process from a substantially liquid raw material, in particular pig iron, includes several injectors which are dispersed in the sidewall of the converter about the converter inner circumference and directed towards the bath level for refining the pig iron. The injectors are designed as supersonic nozzle, which are surrounded by a ring nozzle forming an enveloping gas jet. The injectors are oriented at an angle of max. 43 in relation to the bath surface, with oxygen being introduced through the supersonic nozzle and a mixture of compressed air and natural gas being introduced through the ring nozzle. The jet pulse for the oxygen jet fed through the supersonic nozzle is dimensioned such that an infiltration of the oxygen jet into the melt bath is ensured.

A furnace slag amount estimation device (1) includes: an input unit (11) configured to receive input data including furnace shape data for a converter, data on components and temperatures of molten metal and slag before start of or during blowing treatment, and slag height data in a furnace of the converter; a slag bulk density calculation unit (13) configured to calculate a slag bulk density after the converter is tilted, using the input data and a model; a slag volume calculation unit (14) configured to calculate a slag volume in the furnace after the converter is tilted, using the slag height data after the converter is tilted, the furnace shape data, and a model; and a slag weight calculation unit (15) configured to calculate a slag weight in the furnace after the converter is tilted and slag is discharged, using the calculated slag bulk density and the calculated slag volume.