Mechanism of AZS Refractory Corrosion in Barium Soda Lime Potassium Silicate Glass Melt

Abstract

Al2O3 - ZrO2 - SiO2 refractory corrosion in barium soda lime potassium silicate glass melt have been studied. The composition of glass phase of unused AZS and the concentration profiles of the principal oxides in the glass phases of corroded AZS materials were determined. The refractory samples have been taken from the melting parts of a furnace after production termination as well as from the material where the laboratory static corrosion tests have been conducted. SEM and EDX analysis have been provided on the samples located in the part above and below the metal line corrosion.The corrosion mechanism of refractories in glass melt consists of diffusion of alkalis (Na, K, Ca, Ba) from the glass melt into the refractory, dissolution of the Al2O3 and ZrO2 in the glass phase, diffusion of Zr and Al from the refractory into the glass melt, creation and erosion of the boundary layer area.In the part, where the refractory is not in contact with the glass melt, the mechanism is characterized by a dissolution of alumina in refractory glass phase, diffusion of alkalis in glass phase from the refractory part below the glass level into the upper part, condensation and diffusion of evaporated volatile components of glass melt into the refractory material.

Phase diagram study and thermodynamic modeling of the Na2O–Al2O3–ZrO2 system

“…In particular, soda-lime glass contains up to 14 wt.% Na 2 O (+K 2 O). 1 Alkali oxides such as Na 2 O and K 2 O in molten glass can cause severe corrosion of alumina-zirconiasilica (AZS) refractories at high temperatures 2,3 and induce the defects in glasses. 4 To understand the corrosion mechanism of zirconia-based AZS refractory and the formation of defects in glass, accurate information on the phase diagram and chemical reaction within the Na 2 O-Al 2 O 3 -SiO 2 -ZrO 2 system is essential.…”