The SCRATA Process for the Fumeless Decarburization of Steel by Oxide Injection

THE process which has been developed by the Steel Castings Research and Trade Association, Sheffield, consists of injecting a powdered metal oxide directly into the liquid steel-bath in order to promote a vigorous carbon boil without the emission of brown fume which is normally associated with oxygen lancing. The powder used can be any type of iron oxide; usually crushed millscale, ore concen-trates or fines from sinter plant are used depending on the cost and availability. Additionally, powders con-taining an oxide of a metal which is an alloying element in the steel can be used (e.g. nickel or molybdenum oxides) to achieve simultaneous decarburization and alloying. The carrier gas used is normally compressed air and the powder is injected into the bath through a cons-umable lance, as when using oxygen, although the lance consumption is very much lower.