Patent ID: 6773659
Filing Date: 2004-08-10
Classification: C21C

Abstract:
A lance for injecting a pre-heated oxygen-containing gas into a vessel containing a bath of molten material, the lance including:(a) an elongate gas flow duct extending from a rear to a forward end of the duct from which to discharge gas from the duct, the duct including; (i) inner and outer concentric carbon steel tubes which provide major structural support for the duct, (ii) cooling water supply and return passages 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, (iii) an exterior surface that includes a mechanical device adapted to hold a layer of frozen slag on the duct; (b) a gas inlet for introducing hot gas into the rear end of the duct; (c) a tip joined to the concentric tubes at the forward end of the duct, (d) a protective lining formed from a refractory or other material that is capable of protecting the duct from exposure to gas flow at 800-1400Â° C. through the duct, the lining being a non-metallic material with heat insulating properties when compared to the steel tubes; and (e) a swirl imparting device located in the duct adapted to impart swirl to gas flow through the forward end of the duct.