Filters

1994 - 19963

More filters

20243
Reset filters

Settings

Author: Nölle, Günther × End date: 1996 ×

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Redox conditions during tlie melting of batch
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1995) Flick, Cornelia; Nölle, Günther
    During the mehing down of glass batches a variety of gases are set free. The redox conditions of the melt can be influenced by these gases, because both the gases and the melt are at the same time in a temperature range of 200 K. For the quantification of this influence batches with different charges of coal were heated in comparison with a batch without additions of coal. The final temperature was 1000°C and the heating rate lOK/min. With the continuous measurement of the oxygen partial pressure and the content of CO in the gas the effect of coal on the reactions of gases during the heating of batches can be described.
  • Thumbnail Image
    Item
    Modeling of the bubble population in glass melts
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1994) Roi, Torsten; Seidel, Olaf; Nölle, Günther; Höhne, Diethard
    Previous studies of refining models have mostly dealt with the mathematical description of the behavior of individual bubbles in glass melts. A further step was the modeling of the ascent and growth of groups of bubbles, including restrictions with respect to the spatial distribution of the individual bubbles. Even though no algorithm was derived in this stage which described the total bubble balance during refining, these investigations have produced important results in the field of bubble growth and ascent. In this study, a general and comprehensive mathematical description of the bubble population during refining shall be given, on the basis of the population balance equation used in chemical engineering. The general balance equation for bubbles during refining is presented together with the corresponding computer model. Several experimental investigations into bubble size distribution are described, together with an analysis of the reduction of the bubble concentration in the pot. The obtained values were used as initial parameters and estimates in computer simulations. Some special results of modeling are shown and discussed.
  • Thumbnail Image
    Item
    Equilibrium constant - determination and influence on redox reactions in soda-lime-silica glass melts
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1996) Ortmann, Lars; Höhne, Diethard; Nölle, Günther
    The iron, arsenic and chromium redox equilibrium in an oxide glass-forming melt has been studied quantitatively The equilibrium constant K(T) and the thermodynamic Standard values were determined for the redox reaction in the melt at temperatures between 1000 and 1450 °C. These values were compared with values from the literature. The equilibrium constant is dependent on the temperature and on the concentration of the polyvalent elements. This dependence applies to the polyvalent elements investigated. For each polyvalent element it is possible to find a step in the funcdon lg([R^y]/[R^x) versus R_aO_b- This seems to be explained by the concentradon dependence of the equilibrium constant of the redox reaction. Possibilities to determine the equilibrium constants of the various polyvalent elements are described.