Corrosion Behaviour of Refractory Materials in the Systems Cr2O3 and Cr2O3 – Al2O3 against Glass Melts in Subject to their Composition and the Thermal Conditions*

1 ide (mineral name: eskolaite) for the glass tank's lining. Due to its low solubility in the glass melt, the corrosion resistance of the fireproof material is remarkably improved. Though, a high commodity price and an extensive preparation and processing causes a high price. That condition poses the question, how high or low the eskolaite content has to be, depending on its position in the glass tank, to achieve the best results. At the same time it's also necessary to examine the corundum content. It is known, that the binder phase is foremost attacked by the aggressive glass melt, which results in a destabilisation of the brick's texture. In the last years a few studies were published about this subject, but there was, to our knowledge, no diversified publication. So the aim of this paper is to give a review over refractories of the system Cr2O3–Al2O3 with chromium oxide content from 15 % up to 95 % for typical fibreglass melts. The corrosion proceeds – superficially regarded – in different stages: • The so-called starting reaction, which is accompanied with the soaking of the pores of the refractory by the attacking glass melt • The following diffusion-conditioned reaction of the penetrating substances from the glass melt, the development of diffusion layers and at last • The convection-conditioned erosion of this layer. One must consider that a multiplicity of factors influences the described mechanisms. Therefore an accurate knowledge of the “reaction partners” refractory and glass is absolutely necessary. For this reason the author would like to go a little bit in detail on the analyzed refractories and glasses. So the first Nowadays the most important types of fibre glass are on the one hand continuous filaments and on the other hand insulation fibres, since they are ageand weather-proof, chemically resistant, non-flammable and they also possess a high modulus of elasticity. Traditionally the continuous filament is made of E-glass and is used for glass-fibre reinforced plastic, whereas the insulation fibres are produced from basalt glass or Cglass. In Central and Western Europe basalt glass for health reasons was melted no longer. Instead of it so-called basalt-substitute glasses are produced. It concerns here short glasses with high ferric oxide content. In order to melt these fibre-glasses, you need special refractories based on chromium oxCorrosion Behaviour of Refractory Materials in the Systems Cr2O3 and Cr2O3 – Al2O3 against Glass Melts in Subject to their Composition and the Thermal Conditions*