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

本文研究了低温熔炼对玻璃质量的影响。为了节省制造玻璃产品所需的能源，并抑制化石燃料燃烧产生的二氧化碳的排放，以达到熔池中的高温条件，人们希望采用低温工艺。然而，低温熔炼会抑制玻璃熔体的细化效果，导致玻璃内部含有大量气泡，本研究对玻璃熔体在低于熔化温度200℃的1200~1300℃范围内进行直流电化学处理，并研究了其对玻璃细化的影响。在钠钙硅玻璃熔体上通过铂电极施加1.35DCV，在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的速度高速上升，并在熔体表面形成气泡层。它们还诱导了熔体中的对流。在1h内，含有大量细小气泡(直径0.5 mm)的玻璃熔体上的DCEC使玻璃中的气泡大部分减少，而没有DCEC的玻璃熔体完全不能消除气泡。DCEC还具有控制熔体中过渡金属离子的氧化还原作用。由于金属离子Fe^&lt；2+&gt；→Fe^&lt；3+&gt；的氧化还原位移，使玻璃有效脱色，被认为是一种很有前途的解决熔化温度降低问题的新工艺。

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.