The Effect of Melting at Low Temperature on the Quality of Glass

本文研究了低温熔制对玻璃质量的影响。为了节省制造玻璃产品的能量，并且为了抑制为在熔融槽中获得高温条件而燃烧化石燃料所产生的二氧化碳的排放，期望低温工艺。本文采用直流电化学处理（DCEC）技术，在比熔化温度低200℃的1200-1300℃下对玻璃熔体进行处理，研究了DCEC对玻璃熔体细化效果的影响。通过铂电极对钠钙硅玻璃熔体施加1.35DCV，导致阳极上连续形成平均直径约为1 mm的大气泡。气泡以约1 mm/min的速度上升，并在熔体表面形成气泡层。它们还诱导了熔体中的对流。在含有大量细小气泡（直径<0.5mm）的玻璃熔体上，DCEC在处理1h内基本上消除了玻璃中的气泡，而不加DCEC的熔体则不能完全消除气泡。DCEC也被发现有过渡金属离子在熔体中的氧化还原控制的效果。由于金属离子的氧化还原反应发生了Fe^<2+> →Fe^<3+>的转变，从而有效地对玻璃进行脱色处理。从这些结果来看，DCEC处理是一种很有前途的新工艺，可以解决由于降低玻璃熔制温度而带来的问题。

This work has been done for the investigation of the effect of the melting at low temperature on the quality of glass. The low temperature process has been desired in order to save the energy for the fabrication of the glass products, and also to suppress the emission of carbon dioxide produced by the combustion of fossil fuels to attain high temperature condition in the melting tank. However, low temperature melting causes the depression of fining effect of the glass melts, resulting the glass containing a large amount of bubbles inside.In this study, the direct current electrochemical treatment (DCEC) has been applied on the glass melts at 1200-1300℃, which is 200℃ lower than the melting temperature, and the effect on the fining of the glass has been investigated. The application of 1.35DCV on soda-lime-silica glass melt through the Pt electrodes caused the continuous formation of bubbles with a large mean diameter about 1mm on anode. The bubbles ascended at a high speed about 1mm/min, and form the bubble layer on the melt surface. They also induced the convection in the melts. DCEC on the glass melts containing a large amount of fine bubbles (diameter<0.5mm) decreased the bubbles in the glass mostly within 1h-treatment, while the melting without DCEC could not remove the bubbles at all. DCEC was also found to have the effect of the redox control of transition metal ions in the melts. It could decolorize the glass effectively clue to the shift of the redox of metal ions, Fe^<2+> →Fe^<3+>, From these results, DCEC treatment was considered to be a promising new process solving the problems which are caused by the lowering of the melting temperature.