| 英文摘要 |
According to the on-site investigation to the upstream, midstream and downstream of the domestic solar power industry, this project has investigated interrelated institutions. According to material flow analysis, the import of Solar Cells was 124,856 kg/y in 2007. The Solar Cells in Taiwan were 782,456 kg/y, and 10% of which was sold domestically. Consequently, 201,146 kg/y of Solar Panels assembly plants have put to Taiwan in 2007. The imported Solar Panels were 47,868 kg/y in 2007 and the self-assembled Solar Panels were 4,779,646 kg/y. Deducting from the waste and export volume in 2007, there were totally 3,998,295 kg/y of Solar Panels circulated in domestic market. Based on material flow estimated in 2007, it shows that domestic Solar Cells and Solar Panels wastes were about 19,561 kg/y and 191,186 kg/y, respectively.
Silicon solar cells can be recycled to obtain high purity silicon (99.17%) by a recycling process consisting of dissembling, caustic treatment and acid leaching. After dissembling, the silicon solar cell contains organic material (PMMA 51.56~60.18%, EVA 31.68~32.22%) and inorganic material (metal 1.6~4.39%, silicon 5.85~11.82%). For silicon wafer with connecting wire pattern, the metal content is about 6.31~10.6% with 9.75% of copper, 10.93% of silver and 79.32% of aluminum, respectively. From TGA analysis, it was found that after one hour heating at 400 ℃, the weight loss reached 42.15%, and no further weight loss was observed for further heating up to 8 hours, For solvent treatment process, the chloroform solubility experiments showed that after three hours of chloroform soaking, more than 70% of EVA, and 100% of PMMA can be dissolved. For caustic treatment, 34.5% connecting wire can be recovered. After acid pickling, the remained metal component can be further recovered. The optimum operating parameters for silver metal are: solid-liquid ratio of 0.2g/100 ml, a concentration of 10% aqua regia in the room temperature. The final purity of thus treated single crystal silicon can reach as high as 99.1~99.7% purity.
Meanwhile, based on the point of material flow analysis of LCD panels in Taiwan, the LCD flow between input and output in 2007 has been inventoried. Totally 12,933 tons of glasses, 2,130 tons of plastic, 19.7 tons liquid crystal and 29 tons of ITO had been stored in Taiwan. The waste panels from the LCD manufacturer have all gone to landfill. In other words, there are 6721.3 tons of glasses, 1146.6 tons of plastic, 0.1 tons liquid crystal and 0.2 tons of ITO potentially.
The main purpose of this project is to separate and recover the components of glass substrate, polarizing film, color filter, liquid crystal and indium from scrap LCD panel. Various methods of (1) supersonic washing by ethyl alcohol; (2) high temperature roasting; (3) liquid nitrogen soaking; (4) grinding; (5) pressing by normal pressure; (6) pressing by roll crusher; (7) leaching are adopted to treat the collected scrap LCD panel were carry out in this study. The result of this study reveals that the collected scrap LCD panel has a density of 1.99 g/cm3, a water content of 0.39% and an ash content of 78.43%. It also reveals that the LCD panel contains 0.03% indium, 76.95% glass substrate, 21.63% polarizing film and 0.92% liquid crystal. Among the testing methods, the leaching method was the best method which could 100% separated the liquid crystal, polarizing film, color filter and indium from glass substrate.
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