Mechanism of Alumina Deposition on Alumina Graphite Immersion Nozzle in Continuous Caster

Abstract

Alumina graphite rods were immersed in liquid iron to clarify the mechanism whereby continuous caster immersion nozzles made of alumina graphite were clogged. Even when aluminum was not contained in the iron melt, alumina formed and deposited on the surface of the alumina graphite rod in contact with the iron melt. This experimental result suggests that alumina in the alumina graphite nozzle is reduced by graphite to suboxide gas, and the suboxide gas diffuses to the contact interface with molten steel and is reoxidized into alumina at the interface. This reaction is accelerated by silica in the alumina graphite nozzle. © 1992, The Iron and Steel Institute of Japan. All rights reserved.