A refining vessel for high-temperature melt includes a refractory for gas blowing nozzle that includes a central refractory embedded with metal tubules, and an outer refractory circumferentially surrounding the central refractory. The refractory for gas blowing nozzle has a horizontal projection on which a minimum radius of an imaginary circle encompassing all the metal tubules embedded in the central refractory is R (mm), wherein the central refractory has an outline that falls between one circle that is concentric with the imaginary circle and has a radius of R+10 mm, and another circle that is concentric with the imaginary circle and has a radius of R+150 mm. The central refractory is formed of a MgOC refractory having a carbon content of 30 to 80 mass %, and the outer refractory is formed of a MgOC refractory having a carbon content of 10 to 25 mass %.

A refining vessel for high-temperature melt includes a refractory for gas blowing nozzle that includes a central refractory embedded with metal tubules, and an outer refractory circumferentially surrounding the central refractory. The refractory for gas blowing nozzle has a horizontal projection on which a minimum radius of an imaginary circle encompassing all the metal tubules embedded in the central refractory is R (mm), wherein the central refractory has an outline that falls between one circle that is concentric with the imaginary circle and has a radius of R+10 mm, and another circle that is concentric with the imaginary circle and has a radius of R+150 mm. The central refractory is formed of a MgOC refractory having a carbon content of 30 to 80 mass %, and the outer refractory is formed of a MgOC refractory having a carbon content of 10 to 25 mass %.

A method of operating a BOF bottom stir tuyere having an inner nozzle surrounded by an annular nozzle, including during a hot metal pour phase and a blow phase, flowing an inert gas through both nozzles; during a tap phase, initiating a flow of a first reactant through the inner nozzle and a flow of a second reactant through the annular nozzle, and ceasing the flow of inert gas through the nozzles, wherein the first and second reactants includes fuel and oxidant, respectively, or vice-versa, such that a flame forms as the fuel and oxidant exit the tuyere; during a slag splash phase, continuing the flows of fuel and oxidant to maintain the flame; and after ending the slag splash phase and commencement of another hot metal pour phase, initiating a flow of inert gas through both nozzles and ceasing the flows of the first and second reactants.

A method of operating a BOF bottom stir tuyere having an inner nozzle surrounded by an annular nozzle, including during a hot metal pour phase and a blow phase, flowing an inert gas through both nozzles; during a tap phase, initiating a flow of a first reactant through the inner nozzle and a flow of a second reactant through the annular nozzle, and ceasing the flow of inert gas through the nozzles, wherein the first and second reactants includes fuel and oxidant, respectively, or vice-versa, such that a flame forms as the fuel and oxidant exit the tuyere; during a slag splash phase, continuing the flows of fuel and oxidant to maintain the flame; and after ending the slag splash phase and commencement of another hot metal pour phase, initiating a flow of inert gas through both nozzles and ceasing the flows of the first and second reactants.

To improve the position of a cylindrical ceramic hollow body the invention relates to a securing device for use with a gas purging brick, where the securing device has the following characteristics in its operational position: A base body which, with its bottom and a circumferential wall, defines a cylindrical space with a corresponding central longitudinal axis, the bottom features an opening whose longitudinal axis aligns with the central longitudinal axis the bottom features a ring-shaped channel which extends concentrically around the opening. at least an inner wall of the channel which is adjacent to the opening consists of a material which is plastically ductile under the application of pressure, a ring-shaped compact whose radial wall cross-section increases in size upwards from a lower free end, so that the inner wall of the channel deforms plastically, thereby reducing the cross section of the opening, after the compact is pressed into the channel.

To improve the position of a cylindrical ceramic hollow body the invention relates to a securing device for use with a gas purging brick, where the securing device has the following characteristics in its operational position: A base body which, with its bottom and a circumferential wall, defines a cylindrical space with a corresponding central longitudinal axis, the bottom features an opening whose longitudinal axis aligns with the central longitudinal axis the bottom features a ring-shaped channel which extends concentrically around the opening. at least an inner wall of the channel which is adjacent to the opening consists of a material which is plastically ductile under the application of pressure, a ring-shaped compact whose radial wall cross-section increases in size upwards from a lower free end, so that the inner wall of the channel deforms plastically, thereby reducing the cross section of the opening, after the compact is pressed into the channel.

A method of detecting an abnormality in a blast furnace, wherein the abnormality causes clogging of a tuyere unit of the blast furnace, the method including capturing an image of a raceway unit through an in-furnace monitor window disposed at the tuyere unit; and determining that the abnormality has occurred when a brightness of the captured image is lower than or equal to a predetermined brightness threshold and a rate of decrease in the brightness is lower than or equal to a predetermined brightness-decrease-rate threshold.

A method of detecting an abnormality in a blast furnace, wherein the abnormality causes clogging of a tuyere unit of the blast furnace, the method including capturing an image of a raceway unit through an in-furnace monitor window disposed at the tuyere unit; and determining that the abnormality has occurred when a brightness of the captured image is lower than or equal to a predetermined brightness threshold and a rate of decrease in the brightness is lower than or equal to a predetermined brightness-decrease-rate threshold.

Gas purging element (10) for metallurgical applications, comprising the following features in its mounted state: a ceramic refractory body (10, 30) with a lower end and an upper end, the upper end features an upper front surface, the lower end features a lower front surface (12), a depression (20) extends from the lower front surface (12) into the lower end of the ceramic refractory body (10), the depression (20) comprises a first part (16, 16, 16) of a detachable, form-fit connection to a gas connection element (50), a fluidic connection for a treating gas through at least one gas permeable section (30) of the ceramic refractory body (10) is provided between the depression (20) and the upper front surface.

Gas purging element (10) for metallurgical applications, comprising the following features in its mounted state: a ceramic refractory body (10, 30) with a lower end and an upper end, the upper end features an upper front surface, the lower end features a lower front surface (12), a depression (20) extends from the lower front surface (12) into the lower end of the ceramic refractory body (10), the depression (20) comprises a first part (16, 16, 16) of a detachable, form-fit connection to a gas connection element (50), a fluidic connection for a treating gas through at least one gas permeable section (30) of the ceramic refractory body (10) is provided between the depression (20) and the upper front surface.