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

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.

Characterization of biogenic organic matter (BOM)

Biogenic organic matter (BOM) is of ubiquitous relevance in all aquatic systems. This is due to the fundamental function of the natural organic matter in combination with the microbial activity which guarantees the degradation in and the self purification of water in the hydrological cycle. In addition, the refractory part of the widely distributed BOM acts as effective adsorbent for most water constituents, and in case of mobile fractions as active vehicle for pollutants. In contrast to the broad importance of the occurrence and role of BOM, there is a fairly small variety for its analytical characterization. Especially in the field of in-situ measurements and of the determination in the original concentration range of aqueous samples, relatively little data have been collected. This is partly due to the complex structure of BOM, partly to the limited availability of analytical methods suited for that type of investigations. The aim of the paper is to give typical examples for the a) physical/chemical, b) microbiological and c) technologically orientated methods of the analytical characterization of BOM in aqueous solution and to draw conclusions on the function of BOM in aquatic systems and their use for man.