Reactivity of coke ash on alumina-carbon blast furnace hearth refractories

Authors

Phillip Drain, University of WollongongFollow
Brian J. Monaghan, University of WollongongFollow
Michael W. Chapman, BlueScope Steel LimitedFollow
Robert J. Nightingale, University of WollongongFollow

RIS ID

103412

Publication Details

Drain, P. Brian., Monaghan, B. Joseph., Chapman, M. Wallace. & Nightingale, R. John. (2015). Reactivity of coke ash on alumina-carbon blast furnace hearth refractories. ISIJ International, 55 (9), 1849-1858.

Abstract

Understanding the degradation of blast furnace hearth refractories by coke ash products is a crucial component in achieving long furnace life. This study has been conducted to determine the reactivity of calcium aluminates (CaO·Al₂O₃, CaO·2Al₂O₃ and CaO·6Al₂O₃) in contact with an alumina-carbon refractory at representative hearth temperatures of 1 450° to 1 550°C. The rate of reaction between the alumina-carbon refractory and calcium aluminates was observed to increase with CaO content. The largest reaction layer was observed in CaO·Al₂O₃ followed by CaO·2Al₂O₃ and CaO·6Al₂O₃. The calcium aluminate (CaO·Al₂O₃, CaO·2Al₂O₃) and alumina-carbon reactions observed in this study were found to be consistent with the logarithmic rate law, with the exception of CaO·6Al₂O₃ where no reaction was observed. Energy dispersive spectroscopy analysis indicated the formation of CaO·2Al₂O₃, CaO·6Al₂O₃, corundum (Al₂O₃), plagioclase (CaO·Al₂O₃·2SiO₂₎ and melilite (2CaO·Al₂O₃·SiO₂) at the reaction interface of the reaction couples. The large volume changes due to the formation of these phases may result in spalling at the hot face of the hearth refractory.