Abstract:
A method of analyzing particles of a material which include a constituent is disclosed. The method comprises the steps of exposing particles of the material to x radiation having a range of x-radiation energies, detecting x-radiation intensities at two different energy levels transmitted through the particles, and determining the concentration of the constituent in particles from the detected intensities.
Abstract:
A steelmaking process is disclosed. The process includes producing molten steel and molten steelmaking slag in a steelmaking process, the steelmaking slag including iron units and flux units, and thereafter producing molten iron in a molten bath based direct smelting process using a substantial portion of the steelmaking slag as part of the feed material requirements for the direct smelting process. A direct smelting process is also disclosed. The process includes pre-treating ferrous material including steelmaking slag and thereafter direct smelting molten iron using the pretreated ferrous material as part of the feed material for the process.
Abstract:
A lance for injecting a pre-heated oxygen-containing gas into a vessel containing a bath of molten material is disclosed. The lance (26) includes an elongate gas flow duct (31) from which to discharge gas from the duct. The duct includes (i) inner and outer concentric carbon steel tubes (37, 39) which provide major structural support for the duct, (ii) cooling water supply and return passage means (43, 44) extending through the duct wall from the rear end to the forward end of the duct for supply and return of cooling water to the forward end of the duct, and (iii) a mechanical means in the form of lands (136) on the exterior surface of the duct adapted to hold a layer of frozen slag on the duct. The lance also includes a gas inlet (32) for introducing hot gas into the rear end of the duct. The lance also includes a tip means (36) joined to the concentric tubes at the forward end of the duct. The lance also includes a protective lining formed from a refractory or other material that is capable of protecting the duct from exposure to gas flow at 800-1400 DEG C through the duct. The lining is a non-metallic material with heat insulating properties when compared to the steel tubes. The lance also includes a swirl means (34) located in the duct for imparting swirl to gas flow through the forward end of the duct.
Abstract:
A process for direct smelting metalliferous feed material is disclosed. Iron oxides are partially reduced in a solid state in a pre-reduction vessel. The partially reduced iron oxides are smelted to molten iron in a direct smelting vessel which contains a molten bath of iron and slag and is supplied with a solid carbonaceous material as a source of reductant and energy and with an oxygen containing gas for post-combusting carbon monoxide and hydrogen generated in the vessel. The direct smelting step generates an off-gas that contains sulphur and the off-gas is released from the direct smelting vessel. Part only of the off-gas released from the direct smelting vessel is used in the pre-reduction step to pre-reduce iron oxides in the pre-reduction vessel. Part only of the off-gas is used in the pre-reduction step in order to control the amount of sulphur that is returned with the partially reduced iron oxides to the direct smelting vessel.
Abstract:
A direct smelting process for producing metals from a metalliferous feed material is disclosed. The process includes forming a molten bath having a metal layer (15) and a slag layer (16) on the metal layer in a metallurgical vessel, injecting metalliferous feed material and solid carbonaceous material into the metal layer via a plurality of lances/tuyeres (11), and smelting metalliferous material to metal in the metal layer. The process also includes causing molten material to be projected as splashes, droplets, and streams into a top space above a nominal quiescent surface of the molten bath to form a transition zone (23). The process also includes injecting an oxygen-containing gas into the vessel via one or more than one lance/tuyere (13) to post-combust reaction gases released from the molten bath, whereby the ascending and thereafter descending splashes, droplets and streams of molten material in the transition zone facilitate heat transfer to the molten bath, and whereby the transition zone minimises heat loss from the vessel via the side walls in contact with the transition zone. The process is characterised by controlling the process by maintaining a high slag inventory.
Abstract:
A method of producing metals and metal alloys from metal oxides is disclosed. The method comprises the steps of partially pre-reducing the metal oxides to a pre-reduction degree of at least 60 % in one or more pre-reduction stages. Thereafter, the method comprises completely reducing the metal oxides and melting the metal in a smelt reduction stage. The method is further characterised by carrying out at least one of the pre-reduction stages with one or more of natural gas, reformed natural gas, and partially reformed natural gas as a source of reductant.