A lance (1) for blowing oxygen onto a bath of molten steel including a tip (15) provided with first oxygen ejector (16) and a distributor (17) provided with second ejector (18).

The object of the present invention is to provide a melting/refining furnace for cold iron sources and an operation method for a melting/refining furnace that can increase the heating efficiency of the raw material without causing oxidation of the raw material, reduce the amount of power consumption required for melting the raw material, shorten the melting and refining time, improve the productivity, and reduce costs, and the present invention provides a melting/refining furnace including: one or more through-holes (21) provided to penetrate a furnace wall (2A) of an electric furnace (2); and an oxygen burner-lance (3) provided in the through-hole (21), wherein the oxygen burner-lance (3) includes at least one combustion-supporting gas supply pipe (31) and at least one fuel gas supply pipe (32) which have an opening communicating with an inside of the electric furnace (2), and wherein a high-temperature gas generator (10) is provided in any one or more of the combustion-supporting gas supply pipes (31).

A dephosphorization method using a top and bottom blown converter. This method uses a converter charged with molten iron and slag, to blow an oxygen-containing gas from a top-blowing lance, supply the gas from an inlet of a blowing hole, and supply a control gas from an opening toward an axial center. This method has: a slag top-surface position measurement step, with the top surface of the molten iron measured in advance, measuring an arbitrary position in a top surface of the slag; a slag top-surface difference calculation of slag thickness difference between the measured top-surface positions of the molten iron and the slag; and a jetting condition adjustment step of, using the obtained slag thickness, adjusting a jetting condition of the gas jetted from the top-blowing lance into an appropriate range. The top-blown jetting condition is adjusted by comparing the slag thickness and the depth of a surface depression.

In a method for oxygen-blowing refining of molten iron, an oxygen-containing gas as a main supply gas is supplied from an inlet side of a blowing nozzle for the oxygen-containing gas passing through an outer shell of the top-blowing lance and blown from the blowing nozzle while a control gas is jetted toward inside of the blowing nozzle for at least part of a period of the oxygen-blowing refining from a spout arranged in a side face of the nozzle at a site where the cross-sectional area of the nozzle minimum takes the minimum in the axial direction of the nozzle or a neighborhood thereof so that at least part of the spout exists in each space formed by dividing into two portions by an arbitrary plane passing through a central axis of the nozzle.

A telescoping thermal lance assembly including a housing with an oxygen inlet port. An extension tube disposed in the housing. The extension tube having a cylindrical interior cavity. The extension tube configured to slide at least partially out of the housing when pressurized oxygen is channeled into the inlet port. A cylindrical lance tube is located within the interior cavity of the extension tube and slides partially out of the extension tube when pressurized oxygen is channeled into the housing. A slice rod is located within the lance tube. A cap is attached to the top of the extension tube and spaced apart from the tip of the lance tube. A gas turbine assembly attached above the cap and including a turbine and a plurality of blades that rotationally drive the turbine, rotation of the turbine generating a spark in the igniter section.

When the decarburization refining of molten iron is performed by top-blowing oxygen gas from the top blowing lance, the oscillation of molten iron, a bubble burst, and spitting due to the bubble burst are suppressed. A refining method for a converter includes decarburizing molten iron in the converter with a top blowing lance having Laval nozzles disposed at the lower end thereof by blowing oxygen gas on the surface of the molten iron in the converter through the Laval nozzles, in which one or both of an oxygen feeding rate from the top blowing lance and lance height LH are adjusted in such a manner that an oxygen accumulation index S(F) is 40 or less.

A method for treating molten metals (4) and/or slags in metallurgical baths comprises the introduction of a process gas into a melt bath. The process gas is accelerated to supersonic speed and is introduced below the melt bath surface (5) by means of at least one supersonic nozzle (6) with supersonic speed into the liquid phase of the molten metal (4) and/or into the slag and/or into the region of a phase boundary between molten metal and slag. The disclosure further relates to a metallurgical plant for treating molten metals.

In a method for oxygen-blowing refining of molten iron, an oxygen-containing gas as a main supply gas is supplied from an inlet side of a blowing nozzle for the oxygen-containing gas passing through an outer shell of the top-blowing lance and blown from the blowing nozzle while a control gas is jetted toward inside of the blowing nozzle for at least part of a period of the oxygen-blowing refining from a spout arranged in a side face of the nozzle at a site where the cross-sectional area of the nozzle minimum takes the minimum in the axial direction of the nozzle or a neighborhood thereof so that at least part of the spout exists in each space formed by dividing into two portions by an arbitrary plane passing through a central axis of the nozzle.

The invention relates to a process for injecting particulate material into a liquid metal bath wherein the liquid metal bath contains species to be oxidized, wherein the particulate material is carried to the liquid bath by means of a first gas stream. The solids injection rate is controlled such that the liquid bath temperature and/or the evolution of the liquid bath temperature is maintained within a pre-defined temperature range and the penetration depth of the first gas stream into the liquid bath is controlled by adjusting the flow of the first gas stream. At least one second gas stream is injected into the liquid, wherein the first and the second gas streams are an oxidizing gas, in particular oxygen, and the sum of the gas flows of the first and the second gas streams is determined based on the mass of the species to be oxidized and on the desired time for oxidizing the mass of the species.

A blowing lance tip includes a central stirring gas-supply tube, an inner coolant-inlet tube ending, at one end thereof facing the bath, in a second front wall and having a central opening, an outer coolant-outlet tube, a heat exchange space, and a stirring gas-outlet pipe leading from each opening in the front wall, wherein the second front wall has, at the central opening, an edge which is curved in axial cross-section such that a height (H3) is defined between a leading face of said edge and the third front wall, and such that, in the heat exchange space, a predetermined minimum height (H1) is present on the side facing the central opening.