P-D Refractories - Corrosion Behaviour of Refractory Materials

refractories WORLDFORUM 2 (2010) [3] 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 ex- tensive preparation and processing causes a high price. That condition poses the ques- tion, 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 ag- gressive glass melt, which results in a desta- bilisation of the brick's texture. In the last years a few studies were pub- lished 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 Cr 2 O 3 –Al 2 O 3 with chromium oxide content from 15 % up to 95 % for typical fibreglass melts. The corrosion proceeds – superficially re- garded – 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 reac- tion of the penetrating substances from the glass melt, the development of diffu- sion layers and at last • The convection-conditioned erosion of this layer. One must consider that a multiplicity of fac- tors influences the described mechanisms. Therefore an accurate knowledge of the “re- action partners” refractory and glass is ab- solutely 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 fila- ments and on the other hand insulation fi- bres, since they are age- and weather-proof, chemically resistant, non-flammable and they also possess a high modulus of elastic- ity. Traditionally the continuous filament is made of E-glass and is used for glass-fibre reinforced plastic, whereas the insulation fi- bres are produced from basalt glass or C- glass. In Central and Western Europe basalt glass for health reasons was melted no longer. Instead of it so-called basalt-substi- tute 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 ox- Corrosion Behaviour of Refractory Materials in the Systems Cr 2 O 3 and Cr 2 O 3 – Al 2 O 3 against Glass Melts in Subject to their Composition and the Thermal Conditions* M. Freund T raditionally continuous glass filament is made of E-glass and is used for glass-fibre reinforced plastic, whereas the insulation fibres are produced from basalt glass or C-glass. 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 fibreglasses, special refractories based on chromium oxide (mineral name: eskolaite) for the glass tank's lining are needed. So the aim of this paper is to give a review over refractories of the sys- tem Cr 2 O 3 –Al 2 O 3 with chromium oxide content from 15 % up to 95 % for typical fibreglass melts. The first part of the paper is en- gaged in the characteristics of the refractory bricks due to their pro- duction procedure, and also the characteristics of the attacking glass- es, which cause the corrosion, are succinctly discussed. The experi- mental part of the paper depicts the applied corrosion tests, the re- sults of which are discussed and summarized in the last part of this paper. 1 Introduction More and more durable and specific prod- ucts are needed for industrial applications. Therefore the demand on fibre glass as a construction and insulating material explod- ed during the last years. Mareike Freund P-D refractories Dyko Glass Labor 40549 Düsseldorf Germany E-mail :Mareike.Freund@pd-group.com Keywords: corrosion, Cr 2 O 3 refractories, Cr 3 O 3 –Al 2 O 3 refractories, Received: 10.07.2010 *) The paper presents part of results of M. Freunds diploma thesis which is supported by P-D Refractories DYKO Glass

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