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- ItemTemperature dependence of amber color generation in soda-lime-silica glass(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2000) Müller-Simon, HayoRecently, spectroscopic investigations in the UV-VIS range showed that the amber chromophore in soda-lime-silica glass vanishes with increasing temperature. Oxygen balance calculations have been carried out in order to explain this behavior thermodynamically. The calculations yield that, based on the available standard reaction enthalpies and standard reaction entropies, the product of the ferric and sulfide concentrations decreases with increasing temperature.
- ItemTemperature dependence of the redox State of iron and sulfur in amber glass melts(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1997) Müller-Simon, HayoIn industrially melted amber glass the logarithm [Fe²⁺]/[Fe³⁺] shows no linear dependence on the logarithm of oxygen partial pressure. This nonlinearity is due to the interaction between iron and sulfur which can be described by means of a simple oxygen balance model. The change of chemically dissolved oxygen as a function of the oxygen partial pressure depends on the redox State and has a minimum at intermediate oxygen partial pressures. In this region small variations of the reducing additions in the batch cause large variations of the oxygen partial pressure.
- ItemSelenium flow in the melting of flint glass Containers(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1996) Müller-Simon, Hayo; Kirchner, Ulrich[no abstract available]
- ItemOn-line determination of the iron concentration in industrial amber glass melts(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1995) Müller-Simon, Hayo; Mergler, Kurt WilhelmA sensor has been developed in order to measure the concentration of polyvalent elements on-hne in industrial glass melts. The sensor has been tested on iron in an amber glass melt. A method has been developed in order to determine the area of the measuring electrode, which can change due to glass level variation. The accuracy of the iron determination by means of the voltammetric sensor has been found half the accuracy of x-ray fluorescence analysis.
- ItemPractical strength of glass containers. Part 2. Influence of handling(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1994) Wagner, Jörg; Müller-Simon, Hayo; Lenhart, ArminThe practical strength of container glass depends not only on the stress distribution at the surface, but also on the type and distribution of surface defects. After the elimination of the influence of the container shape by means of finite element methods, different types of defect show a different behaviour in the Weibull plot. This behaviour can be used to compare different handling materials. The materials used at the cold end cause no measurable weakening of the strength. A special type of defect could be associated with the transfer conveyour belt. Carbon and brass were compared as deadplate materials without finding a specific influence on the container strength.
- ItemOn the interaction between oxygen, iron and sulfur in industrial glass melts(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1994) Müller-Simon, HayoThe oxidation state of iron in industrially molten glasses has been investigated in the cold glass and related to the oxygen activity in the glass melt. The prediction of the oxidation state of iron in the cold glass from the measured oxygen activity in the glass melt is disturbed in such a way that in oxidized molten glasses the Fe²⁺ content and in amber glasses the Fe³⁺ content increase during cooling. This behavior can be explained by an interaction due to the oxidation reactions of sulfur known from the literature during cooling. The reaction constants result in electrochemical standard potentials which agree with voltammetric studies.
- ItemPractical strength of glass containers : Part 1. Influence of the type of defect(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1994) Müller-Simon, Hayo; Wagner, Jörg; Lenhart, ArminThe practical strength of container glass depends not only on the stress distribution at the surface, but also on the type and distribution of surface defects. After the elimination of the influence of the container shape by means of finite element methods, different types of defect show a different behaviour in the Weibull plot. Especially seeds and blisters are shown to be twice as dangerous as inhomogeneides caused by handling materials. The accuracy of the stress determination is limited, thus, an identification of different types of inhomogeneities from the Weibull plot is not possible under the present conditions.
- ItemRedox behavior of selenium in industrial soda-lime-silica glasses(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2001) Müller-Simon, Hayo; Bauer, Johannes; Baumann, PatrickΑ thermodynamic model for the calculation of the redox distributions of polyvalent elements which is based on the balance of chemically bonded oxygen in glass melts has been applied to the redox reactions of selenium. Α set of reliable thermodynamic data of the selenium oxidation reactions has been derived using results of electrochemical, optical and wet-chemical investigations. Calculation results showed that selenium is reduced during cooling by iron as well as by sulfur. Due to the small selenium/sulfur ratio in selenium-decolorized flint glasses under industrial conditions selenium is completely reduced to the selenide state. Obviously, in industrially melted flint glasses selenium decolorization is not provided by the pink color of elemental selenium as assumed so far but by the amber color of iron selenide, which is supported by the fact that selenium decolorization always causes an additional yellow tint besides the required red tint and a considerable shift of the UV edge to larger wavelengths.
- ItemApplication of oxygen sensors in industrial glass melting tanks(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1996) Baucke, Friedrich G. K.; Werner, Ralf D.; Müller-Simon, Hayo; Mergler, Kurt WilhelmΑ comparative study of electrochemical oxygen sensors for glass melts employing zirconia solid electrolytes developed by Schott Glaswerke and by the HVG is reported. The sensors applied in a feeder Channel of a melting tank producing green glass yielded slightly different but reproducible results despite different constructions. The zirconia reference electrodes achieved more than one year active lifetime at 1200°C. Their potentials directly compared over extended periods agreed within less than 3 mV. The potential differences of the platinum measuring electrodes were traced to temperature gradients. Newly installed platinum electrodes show "induction periods" caused by convectional and diffusional equilibration of adhering surface with bulk melt. Unexpected sudden oxygen inhomogeneities of the melt were detected and explained.
- ItemOxygen balance in sulfur-containing glass melts(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1998) Müller-Simon, HayoIn sulfur-containing glasses the Fe²⁺/Fe³⁺ ratio at a given oxygen partial pressure shows a considerable shift compared to glasses without sulfur. This effect is caused by an electron exchange and governs the redox behavior of industrial glass melts at fming temperature. The electron exchange is formulated by a thermodynamic approach which can quantitatively describe the redox reactions between melting temperature and room temperature in flint glasses. In amber and green glasses this dependence is superimposed by the dissolution of SO₂-containing bubbles, which results in an additional shift of the oxygen partial pressure in the direction of the sulfur solubility minimum during cooling. From this shift the maximum solubility of sulfite in soda-lime-sihca glass melts can be estimated to be about 0.025 wt% SO₃. Resorption curves of sulfite sulfur in the melt describe the refining quahty. They can serve as a tool for improving the secondary refining in sulfur-containing industrial glass melts.