TH49470A - Direct smelting process - Google Patents

Abstract

DC60 (July 31, 2012) Direct Smelting Process for Metal Production from Metal-Containing Feeds: This direct smelting process is based on the use of a molten bath, where smelting occurs primarily in the metal layer. Conveying gases/metal-containing/solid carbon-containing feeds are injected into the metal layer through injection/air jet pipes, and oxygen-containing gases are injected into the upper area above the molten bath, and subsequent combustion reaction gases are released from the molten bath. The injection of metal-containing and solid carbon-containing feeds causes the molten material to be released from the molten bath as splashes, drips, and streams, creating a transition area. The process is characterized by the creation of a tube of solid material on the outlet end of at least one injection cylinder as metal-containing and carbon-containing feeds are injected through the injection/air jet pipes, thus extending the effective length of the injection/air jet pipe. This direct smelting process for metal production from metal-containing feeds has been revealed. This is a molten bath process where smelting primarily occurs in the metal layer. A conveying gas/feed containing metallic/solid carbonized material is injected into the metal layer through a blasting cylinder, and oxygen-containing gas is injected into the upper area above the molten bath. Subsequent combustion reaction gases are released from the molten bath. The injection of metallic and solid carbonized feed causes the molten material to be released from the molten bath as splashes, drips, and streams, creating a transition zone. The process is characterized by the formation of a tube of solid material at the outlet of at least one blasting cylinder as the metallic and carbonized feed is injected through the blasting/air jet tube, thus extending the length of the blasting/air jet tube.

Claims (13)

1. Direct smelting process for the production of metals from metal-containing feed materials, consisting of the following steps: (a) creation of a molten bath containing a layer of metal and a layer of slag on top of this metal layer in a metal vessel; (b) injection of conveying gas, metal-containing feed materials, and solid carbon-containing materials into the metal layer through injection pipes/air jets positioned above and extending to the surface of the metal layer, and the molten material being expelled from the molten bath as splashes, drips, and streams to the area above the stationary surface of the molten bath to create a transition zone; (c) smelting of the metal-containing feed material into the metal layer; (d) injection of oxygen-containing gases into the vessel through one or more injection pipes/air jets, and subsequent combustion reaction gases being released from the molten bath, where the subsequent rising and falling of the splashes, drips, and streams of molten material in the transition zone transfers heat to the molten bath, and the transition zone minimizes heat loss from the vessel through the side walls in contact with the transition zone, and this process is characterized by the creation of a tube of solid material on the outlet of at least one injection pipe/air jet. When metallic and carbon-containing feed materials are injected through the injection/air vent pipe for solid material injection, an effective lengthening of the injection/air vent pipe occurs. 2. The process defined in Claim 1, whereby step (d) of the pipe fabrication involves the injection of metallic and/or carbon-containing materials through the injection/air jet tube for solid material injection so that the endothermic nature of these materials creates a boundary around the outlet of the injection/air jet tube for solid material injection that is below the slag solidification temperature. 3. The process defined in claim 1 in which the transported gas in step (b) consists of an oxygen-free gas. 4. The process defined in one of the aforementioned claims, which involves the injection of a metal and/or carbon-containing feed material in step (b) so that each tube is formed as a coaxial expansion and each tube injects/explodes solid material. 5. The process defined in claim 4, which includes mass flow control of metallic and carbon-containing feed materials and/or conveyor gas velocity control of metallic and carbon-containing feed materials. 6. A process defined in one of the aforementioned claims, which involves maintaining the outlet of the injection/air jet pipe for each solid material injection cylinder at a temperature below the slag solidification temperature in order to support the initial solidification of the solid material at the end. 7. A process defined in one of the aforementioned claims, which involves the installation of injection/air venting pipes for the injection of each solid material cylinder, so that the outlet is below the surface of the melting pool and above the metal layer. 8. A vessel for the production of metal from a metal-containing feedstock by a direct smelting process, in which the vessel contains a molten pool with a layer of metal and a layer of slag on top of this metal layer. The vessel consists of: (a) a furnace constructed of refractory material with a base and sides in contact with the molten metal; (b) side walls that extend upwards from the sides of the furnace and in contact with the slag layer; (c) one or more injection/blowout pipes extending downwards into the vessel and injecting oxygen gas into the vessel; (d) injection/blowout pipes for injecting a number of solid materials downwards and into the vessel and injecting conveying gas, metal-containing feedstock, and carbon-containing materials into the metal layer, with the outlet end of at least one injection/blowout pipe positioned above the surface of the metal layer during the operation of the direct smelting process in the vessel, and with a pipe hardened on it of solid material causing the outlet end of the injection pipe; and (e) a pathway for draining the molten metal and molten slag from the vessel. 9. The containers specified in claim paragraph 8, where the outlet of the injection/air vent pipe for the injection of solid material in each cylinder is at least 150 millimeters above the stationary surface of the metal layer. 10. Containers as defined in claim clause 8 or 9, where the outlet of the injection/spray pipe for injecting solid material is located no more than 500 millimeters above the stationary surface of the metal layer. 11. A vessel as defined in any of the claims 8 through 10, in which the injection/air jet pipe for injection of solid material consists of (a) a long, hollow section which provides a central passage for the feed material and has an inlet and outlet end; and (b) an external water-cooled casing. 12. The vessel defined in claim 11, which extends beyond the water-cooled casing at the outlet of each cylinder's injection/air discharge pipe. 13. A vessel as defined in any of the claims 8 through 12, in which the injection/air vent pipe for each solid metallic material cylinder extends downward and is tilted inward at an angle of 30–60 degrees to the vertical.