Implementation of Novel Carbon Bonded Filter Materials for Steel Melt Filtration – an Overview

Chr. G. Aneziris, M. Emmel

TU Bergakademie Freiberg Institute of Ceramic, Glass- and Construction Materials Agricolastraße 17, 09599 Freiberg/Germany

Revision 31.05.2014, 23.09.2014

Volume 7, Issue 1, Pages 73 - 82

Abstract

In course of the present work an overview, providing information about the development and characteristic properties of novel active and reactive ceramic foam filter materials for steel melt filtration, is presented. The so-called active filters, based on carbon bonded alumina, are subdivided into an activation due to increased amorphous carbon amounts and an activation due to oxide coatings, whose chemistry equates to that of non-metallic inclusions. These filter types are expected to improve the filtration of especially exogenous, as well as primary and secondary endogenous inclusions. In contrast, the reactive filters, consisting of carbon bonded magnesia, are supposed to decrease the formation of both tertiary and quaternary endogenous inclusions. Here, the carbothermal reduction of the MgO results in gaseous Mg, which reduces the dissolved oxygen in the steel melt. A combination of both filter materials provides the active, as well as the reactive functionality in one filter type. The resulting in situ spinel formation moreover counteracts the shrinkage of the filter material during casting. In collaboration with the industry, testing of a selection of novel filters led to the identification of the influence of the chemistry in filtration processes. Here, alumina coated filters possessed the highest filtration potential.

Keywords

ceramic foam filter, steel melt filtration, carbon bonded oxides

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