Materialization Study on Transformation of Insulated Glass-Ceramic from Mixing TFT-LCD Waste Glass and Basic Oxygen Furnace Slag by Thermal Treatment
Date Issued
2010
Date
2010
Author(s)
Lin, Tung-Hung
Abstract
The objective of this study was to use thin film liquid crystal display (TFT-LCD) waste glasses from optoelectronic industry and basic oxygen furnace (BOF) slags from integrated steel plant as reused materials to produce insulated glass ceramic materials that have superior dielectic and mechanical properties with low coefficient of thermal expansion . This study selected the ratio of TFT-LCD waste glass to BOF slag as 6：4 and 7：3 by weight based on quenched vitreous slag composition which has the feasibility to initiate good insulating properties of MgO-Al2O3-SiO2 (MAS) glass ceramic system.
The vertification of MAS glass-ceramic system was conducted by addition of 10-20 % MgO (w/w)、15-20 % Al2O3 (w/w) and 10 % TiO2 (w/w) , and analysed the effect of addition of modifier on crystal phases and thermal treatment temperature. In addition,regarding property analysis corresponding to the ratio of TFT-LCD waste glass to BOF slag as 7：3 (w/w) with various proportions of modifier, the effect of temperature on thermal properties and mechanical properties as well as the assessment of potentiality of material reultilized from mixing TFT-LCD waste glass and BOF slag which formed the insulating glass-ceramics were investigated .
The results showed that the ratios were precipitated crystalline via heat treatment when TFT-LCD waste glass and BOF slag in the ratio of 7：3 with addition of 20 % MgO and 15-20 % Al2O3 (w/w) , which contained anorthite and wollastonite in the CaO-Al2O3-SiO2 (CAS) , forsterite and cristobalite in the MgO-Al2O3-SiO2 (MAS) system. The above crystalline phases in glass-ceramic systems are consequently suitable for thermal shock resistant and insulation.
Besides the production of crystalline phases in lower temperature, it also contributed to phase separation and crystal growth due to addition of TiO2. But TiO2 addition resulted in the decrease of phase relative intensity of forsterite in MgO-Al2O3-SiO2 (MAS) system,it also indirected affected the specimens on thermal and mechanical properties.
The optimal operational conditions to reutilize wastes as insulating glass ceramics could be found as follows. (1)TFT-LCD waste glass and BOF slag in the ratio of 7：3 with MgO addition of 15-20 % and Al2O3 addition of 20 %. (2)The resulted low coefficient of thermal expansion similar to microchip’s which could be applied to electronic ceramic package.(3)One-step sintering and heat treatment at 980 ℃ for 0.5h could be employed to obtain glass-ceramics with flexural strength up to about 257.6 MPa and compressive strength up to about 732 MPa.
Mechanical properties will influence the yield on glass-ceramic process in pratical operation, and the sintered materials could meet the required properties in the range between 860 ℃and 900 ℃.
Subjects
TFT-LCD Waste Glass
Basic Oxygen Furnace Slag
MAS glass-ceramic system
Insulated Glass-Ceramic
Mechanical Properties
Thermal Properties
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-99-R97541128-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):901046da922b4d52c9851b7187c76cd5