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Author: Gebhardt, Franz × End date: 1997 ×

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    Chromic oxide blocks for use in the container glass industry
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1997) Boymanns, Gerda; Gebhardt, Franz; Georenz, Edmund
    Large parts of the tank superstructure of soda - lime - silica glass melters for the production of Hat and container glass are mostly lined with fused-cast AZS blocks today These linings are standind about 8 to 10 years. However, from pracdcal experience it is well-known that certain furnace areas such as doghouse corners, weirs, throat assemblies etc. are prone to progressive corrosion. In order to eliminate these shortcomings by providing cost-effective Solutions, isostatically pressed and sintered chromic oxide blocks were tested successfully for use in soda - lime - silica glass furnaces. Questions concerning the corrosion behaviour, the colouradon of the glass and the formation of Chromate are discussed.
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    Feuerfeste Werkstoffe für den Betrieb von Glasschmelzöfen : Stand der Technik und Ausblick
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1997) Gebhardt, Franz
    [no abstract available]
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    Non-destructive testing of ceramically bonded refractories - Application of ultrasound and microwaves
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1995) Ulizka, Stanislav; Hädrich, Helmut; Gebhardt, Franz
    Quality control on refractory bricks is either mostly destructive or methods are used which require samples with a certain geometry. In a joint project between the University of Erlangen and industry the applicability of non-destructive testing methods for sintered refractory bricks was tested. Various materials with artificial flaws were measured in transmission with ultrasound (500 kc/s) as well as with microwaves (24 to 40 Gc/s) and the results were compared. Despite of good results, the testing with ultrasound proved to be unsuitable for the measurements of greater lots, because the open-pore blocks have to be coupled in water. An excellent alternative is the transmission measurement with microwaves. With both methods structural inhomogeneities as well as density differences or inclusions can be detected.
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    Silica wrecking material as a substitute for glassmaking sand in a container ware batch
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1995) Boymanns, Gerda; Gebhardt, Franz; Schmidt, Dieter; Weiler, Manfred
    Industrial high-temperature processes like steel making, glass melting, cement production etc. need sintered or fused-cast refractory materials. During the operating time the reactions of the fused product and the bricks of the furnaces lead to contaminated refractory materials, which should no longer be disposed of and, therefore, have to be recycled, that means converted to raw materials for different industrial processes. Regarding these conditions the authors have tried to introduce silica bricks from the crown of glass melting furnaces and from the walls of coke ovens into the batch, replacing the glassmaking sand. First in laboratory-scale tests the melting behaviour and the optimum grain size distribution of ground silica bricks were studied. After a successful termination of these laboratory tests the results were transferred to an industrial furnace for melting container ware, replacing step by step the glass making sand without observing any stones or cords in the melted glass.