A tuyere comprising an inner tube including a lower section having a first diameter, an upper section having a second diameter smaller than the first diameter, and a converging transition section having a converging angle Θ from 30° to 60° connecting the lower section to the upper section, the inner tube terminating in an inner nozzle at a downstream end of the upper section; and an outer tube surrounding the inner tube so as to create an annulus there between, the outer tube including a lower section having a third diameter larger than the first diameter, an upper section having a fourth diameter smaller than the third diameter but larger than the second diameter, and a converging transition section having connecting the lower section to the upper section, the outer tube terminating in an outer nozzle at a downstream end of the upper section.

Methods for controlling the position of a lance supplying oxygen to a furnace containing a bath of molten metal. The methods include the steps of continuously detecting actual conditions associated with the furnace, continuously comparing the actual conditions to target parameters corresponding to the actual conditions, and continuously adjusting the position of the lance with respect to the furnace based on the comparison of the actual conditions to the target parameters.

Smelting metalliferous feed material process forming molten metal in smelting apparatus including smelt cyclone above and communicating with smelting vessel to contain molten metal and slag bath, including: partially reducing and melting feed material in smelt cyclone, allowing the molten partially reduced feed material flow downwardly into vessel, supplying oxygen-containing gas and carbonaceous material to vessel, smelting molten partially reduced feed material in molten metal and slag bath in vessel forming molten metal discharged from vessel and reaction products projected upwardly from molten bath, at least partially combusting combustible materials in reaction products in vessel space above molten bath, supplying oxygen-containing gas to smelt cyclone. Further combusting reaction products in smelt cyclone, discharging from smelt cyclone offgas including reaction products, supplying oxygen-containing gas into offgas duct upstream high temperature section combusting remaining offgas combustible materials while sufficiently hot for safe ignition and avoiding downstream burner-managed incineration.

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.

A tuyere comprising an inner tube including a lower section having a first diameter, an upper section having a second diameter smaller than the first diameter, and a converging transition section having a converging angle from 15 to 35 connecting the lower section to the upper section, the inner tube terminating in an inner nozzle at a downstream end of the upper section; and an outer tube surrounding the inner tube so as to create an annulus there between, the outer tube including a lower section having a third diameter larger than the first diameter, an upper section having a fourth diameter smaller than the third diameter but larger than the second diameter, and a converging transition section having connecting the lower section to the upper section, the outer tube terminating in an outer nozzle at a downstream end of the upper section.

The object of the present invention is to improve the efficiency when operating the melting/refining furnace of the cold iron source using a burners and a lance, or during refining, and the present invention provides a method for operating a melting/refining furnace comprising a through hole so as to penetrate a furnace wall, at least one burners provided in the through hole; and at least one lances installed in an oxidant gas supply hole provided above the through-hole for the burner, wherein an amount of oxygen introduced in the melting step is adjusted to a range calculated based on a the furnace volume.

A smelting apparatus that includes (a) a smelting vessel (4) that is adapted to contain a bath of molten metal and slag and (b) a smelt cyclone (2) for pre-treating a metalliferous feed material positioned above and communicating directly with the smelting vessel The apparatus also includes an oft-gas duct (9) extending from the smelt, cyclone for discharging an off-gas from the smelt cyclone. The off-gas duct has an inlet section (18) that extends upwardly from the smelt cyclone and is formed to cause off-gas to undergo a substantial change of direction as it flows through the inlet section of the off-gas duct.

The present invention relates to a method for pneumatically blowing a powdery substitute reducing agent in a dense flow process, by means of a transport gas, into a gasification reactor, or via a tuyere into a blast furnace. The substitute reducing agent is gasified in a gasification reaction. The transport gas comprises a fuel gas, the constituents of which or the oxidation constituents of which are at least partly involved in the gasification reaction.

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 producing steel by charging a furnace with scrap metal and agglomerated oxy-carbon material into a workspace of a furnace, to reduce specific electricity consumption when melting. Increasing the iron output quantity by inputting electric energy, fuel, a carburizer, a flux and gaseous oxygen, using electric arc melting with decarburization of a metal bath, and releasing metal and slag from the furnace. Prior to melting, a portion of the material is loaded with a first portion of the metal charge into the central zone of the furnace, and the remaining material into the melted charge during melting 0.5-10 kg/min per 1 megavolt-ampere of electric arc transformer power. The oxy-carbon material size is between 5 and 80 millimeters.