The Stabilization of Waste Funnel Glass of CRT by SiO 2 Film Coating Technique

Jyh-Herng Chen, Yu-Hao Chang, Chaochin Su and Kai-Chung Hsu
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Jyh-Herng Chen: Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, 1, Section 3, Chung-Hsiao E. Rd., Taipei 10608, Taiwan
Yu-Hao Chang: Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, 1, Section 3, Chung-Hsiao E. Rd., Taipei 10608, Taiwan
Chaochin Su: Department of Molecular Science and Engineering, National Taipei University of Technology, Daan, Taipei 10608, Taiwan
Kai-Chung Hsu: Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, 1, Section 3, Chung-Hsiao E. Rd., Taipei 10608, Taiwan

Sustainability, 2021, vol. 13, issue 16, 1-12

Abstract: The funnel glass of the CRT monitor contains about 22–28% of lead oxide, of which lead is a highly toxic species and hazardous to the environment. This study proposes a process to form a protective layer of SiO 2 film coating on the funnel glass to reduce the hazardous effect of lead leaching to the environment. The film coating benefits from the advantages of the sol–gel method. There are two key procedures of the stabilization technique, including the alkaline treatment and the formation of SiO 2 coating from TEOS. The results show that the funnel glass powder treated with 10 M NaOH can produce a mushy layer on the surface. The mushy layer, which comprises OH − and water, can promote the formation of the SiO 2 film layer on the surface of funnel glass powder. The conditions of the SiO 2 film coating proposed in this study are: alkaline treatment by 10 M NaOH, the addition ratio of TEOS and funnel glass powder 2: 1, reaction temperature 40 °C, and reaction time 1.3 h. The EDS and ESCA results show that the Pb peak intensity on the surface of funnel glass decreases with the film coating. In the TCLP test, the leaching amount for Pb of the SiO 2 film coated funnel glass powders is 0.7 mg/L, which is far lower than the standard in Taiwan EPA. Based on the experimental results, the formation mechanism of the SiO 2 film layer on the surface of waste funnel glass powder is proposed. This study demonstrates that the SiO 2 film coating is a potentially effective method to solve the problem of the waste funnel glass.

Keywords: stabilization; waste funnel glass; lead; SiO 2 film; mushy layer (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2021
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