| Sulfur Redox Equilibrium in Mixed Alkali Silicate Glass Melts |
| Ki-Dong Kim, Jong-Hee Hwang1 |
Department of Materials Science and Engineering, Kunsan National University
1Korea Institute of Ceramic Engineering & Technology |
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| ABSTRACT |
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The dependence of sulfur redox behavior and its diffusivity on temperature and composition was studied in mixed alkali silicate melts by means of square wave voltammetry (SWV) at different frequencies in a temperature range of $1000^{circ}C$ to $1400^{circ}C$. The voltammograms showed two reduction peaks at high frequency but only one peak at low frequency. Irrespective of $K_2O/(Na_2O+K_2O)$, each peak potential due to reduction of $S^{6+}$ to $S^{4+}$ and $S^{4+}$ to $S^0$ moved toward a negative direction with temperature decrease, and the peak current showed a strong dependence on frequency at a constant temperature. However, the compositional dependence of the peak potential showed an inconsistent behavior with an increase of $K_2O$. The mixed alkali effect was not observed in sulfur diffusion. This inconsistency of both peak potential and diffusion for compositional dependence may be derived from the strong volatilization of sulfur in melts. |
| Key words:
Sulfur, Redox equilibrium, Diffusion, Voltammogram |
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