Fe2O3於TFT-LCD廢玻璃混合轉爐石製備絕緣玻璃陶瓷影響之研究

Abstract

本研究以薄膜電晶體液晶顯示器(Thin Film Transistor Liquid Crystal Display, TFT-LCD)廢玻璃及一貫作業煉鋼轉爐石(Basic Oxygen Furnace Slag, BOF slag)為原料，經熔融均質化及燒結緻密化熱處理製成絕緣玻璃陶瓷，探討轉爐石中Fe2O3含量變化對絕緣玻璃陶瓷性質之影響。研究共分三階段，第一階段固定TFT-LCD廢玻璃與轉爐石之比例，額外添加純物質Fe2O3以分析「Fe2O3含量」-「晶相」-「機械、介電特性」之關聯性；第二階段以產出優良機械、介電特性之絕緣玻璃陶瓷為目的，以不同Fe2O3含量之轉爐石進行成分調配，評估TFT-LCD廢玻璃與轉爐石製備絕緣玻璃陶瓷之可行性；第三階段整合一、二階段之結果，研析兩階段中Fe2O3含量對絕緣玻璃陶瓷性質影響之一致性。 結果顯示，Fe2O3可作為成核劑，使晶相在較低熱處理溫度析出且形成較多晶相種類。Fe2O3添加量增加可提升機械性質，使緻密化程度增加、密度上升並增強抗折強度。然而，介電性質並未隨Fe2O3添加量增加而獲得改善。 TFT-LCD廢玻璃與轉爐石混合比例為7：3，其中轉爐石由爐前渣與爐後渣比為5：5所組成，此配比於820℃進行熱處理所得試樣具有良好之機械強度及介電性質。其密度為2.64 g/cm3、抗折強度為110 MPa、介電常數為8.8、逸散因子為0.0043、品質因子為235、介電損失因子為0.037。因此，本研究調整轉爐石之爐前/爐後渣比例以改變配比中Fe2O3含量，確實可提升絕緣玻璃陶瓷性質，同時達到減少物質及能源使用之目標。 兩階段之試驗結果顯示，Fe2O3含量變化對晶相、機械強度及介電特性造成之性質差異具有一致性，故以TFT-LCD廢玻璃及轉爐石為原料製備絕緣玻璃陶瓷，Fe2O3確為主要影響因子之一。

The objective of this research was to use thin film liquid crystal display (TFT-LCD) waste glass and basic oxygen furnace (BOF) slag as recycled materials to produce insulating glass-ceramic by thermal treatment. In addition, the effects of Fe2O3 content in the BOF slag on the insulating glass-ceramic’s crystalline phase, mechanical, dielectric and thermal expansion properties were also experimented and discussed in details. There were three experimental stages conducted in this study. The first stage was to fix the weight ratio of TFT-LCD waste glass to BOF slag by adding pure reagent of Fe2O3 in order to analyze the relevance of Fe2O3 content to the characteristics of the products, such as crystalline phase, mechanical and dielectric properties. The second stage was to adjust the input ingredients of BOF slag which contains various Fe2O3 content to produce insulating glass-ceramic with excellent mechanical and dielectric properties. The third stage was to analyze the consistency of the effects of Fe2O3 on the production of insulating glass-ceramic from the first and second stage. The results indicated that Fe2O3 could act as nucleating agent to promote crystallization at lower thermal treatment temperature and stimulated the formation of a wide variety of crystal types. In addition, increase in Fe2O3 content would enhance glass-ceramic’s mechanical properties including density and flexural strength. However, dielectric properties did not improve with Fe2O3 addition. When TFT-LCD waste glass and BOF slag was blended in the ratio of 7:3 while BOF slag was prepared with pre-BOF slag and post-BOF slag in the ratio of 5:5, under heat treatment temperature of 820℃, the insulating glass-ceramic exhibited satisfactory characteristics with product density (2.64 g/cm3), bending strength (110 MPa), dielectric constant (8.8), dissipation factor (0.0043), quality factor (235), and dielectric loss factor (0.037). The final product of glass-ceramic had good mechanical strength and dielectric properties. Therefore, this research concluded that the adjustment of the pre/post BOF slag ratio would effectively improve insulating glass-ceramic properties and achieve the goal of reducing the use of additional material and energy. According to the results of first and second stage, it demonstrated that the differences of crystalline phase, mechanical and dielectric properties caused by the Fe2O3 content were consistent. Therefore, it is promising to manufacture insulating glass-ceramic from TFT-LCD waste glass and BOF slag, in which Fe2O3 would play one of the main affecting factors.