Experimental Study on Indium Recovery from Discarded TFT-LCD Panels

Abstract:

With the rapid development of the technology of liquid crystal display, LCDs have become the main stream displays. However, if there are no appropriate ways to recycle the discarded LCDs, the environment will be polluted and the resources will be wasted. TFT-LCD panels mainly consist of the color filter (CF) substrate and the thin film transistor (TFT) substrate which both have a surface covered with indium-tin oxide (ITO). ITO layer contains the metal of indium which is rare, precious and of high value. In view of the difference of the structure and material of the CF substrate and TFT substrate, an efficient and green process has been presented for recycling the indium by means of theoretical analysis and experimental verification. Under heating condition, the sodium hydroxide solution is used to dissolve the color filter of the CF substrate and the ITO layer attached to the color filter can be eliminated quickly and the metal indium can be enriched by filtering solution. By grinding the ITO layer on the TFT substrate with the aid of water-proof sand paper and collecting ITO scraps, indium can also be enriched quickly. The experiments show that the indium content of the CF substrate and TFT substrate are both quite low. Enriching indium on the premise of not dissolving indium is beneficial to the concentrated recovery of indium and is helpful to raise the recycling efficiency and protect the environment.

• Periodical: Applied Mechanics and Materials (Volumes 365-366)
• Pages: 1136-1143
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.365-366.1136
• Online since: August 2013
• Authors: Yu Lin Wang, Fang Qiu Chen, Kai Zhao, Hai Juan Hu, Guang Fu Liu
• Keywords: Indium, ITO, LCD Panel, Recovery, TFT-LCD, TiN

References

[1] Kye-Sung Park, Wakao Sato, Guido Grause, Tomohito Kameda, Toshiaki Yoshioka, Recovery of indium from In2O3 and liquid crystal display powder via a chloride volatilization process using polyvinyl chloride, J. Thermochimica Acta. 493(2009) 105- 108.

DOI: 10.1016/j.tca.2009.03.003

[2] Kunihiko Takahashi, Atsushi Sasaki, Gjergj Dodbiba, Jun Sadaki, Nobuaki Sato and Toyohisa Fujita, Recovering indium from the liquid crystal display of discarded cellular phones by means of chloride-induced vaporization at relatively low temperature, J．Metallurgical and Materials Transactions A. 40 (2009).

DOI: 10.1007/s11661-009-9786-4

[3] Shukai Wang , Indium metallurgical, Press of Metallurgy Industry , Beijing, (2006).

[4] Dongmei Yang, Yuwen Guo, Jingyang Liu. Dissolution characteristics of the main elements of the waste TFT-LCD panel , J. Research of Environmental Sciences, 25(2012)431-435.

[5] Jiaxiang Liu, Yong Gan, Yan Zhang, Use the waste ITO target recycling metal indium, J. Chinese Journal of Rare Metals , 5(2004)947-950.

[6] Zhihong Liu, Yuhu Li, Qihou Li, Kan Ai, Duomo Zhang, Study of separating indium and tin from soak solution of ITO waste target by sulphuration precipitation, J. Mining and Metallurgical Engineering, 5(2005)53-56.

[7] Shukai Wang, Recovery of indium tin from the waste ITO target by mixed acid soaking and vulcanization process, J . China Engineering Science, 9(2009)29-32.

[8] Jinhui Li, Song Gao, Huabo Duan, Lili Liu, Recovery of valuable materials from waste liquid crystal display panel, J. Waste Management, 29(2009)2033- (2039).

DOI: 10.1016/j.wasman.2008.12.013

[9] Jian Chen. Recovery of indium from waste ITO target, J. Chinese Journal of Rare Metals, (2003)101-103.

[10] Kazuo Kondo, Michiaki Matsurmoto, Separation and concentration of indium( III) by an emulsion liquid membrane containing diisostearyphosphoric acid as a mobile carrier, J. Separation and Purification Technology, 13(1998)109-115.

DOI: 10.1016/s1383-5866(97)00064-6

[11] D. Annie, With contain phosphate group of ion exchange phase recovery indium, germanium and gallium method. hydrometallurgy, 2(1989)77-80.

[12] M Masaaki, A Masahiro, Recovery of indium in the sulfuric acid soaking solution of zinc soak residue with chelate resin, J. The Chemical Society of Japan, 9(1990) 976- 981.

[13] Kurita Shigeru, et al, China. Patent JP2001207282. (2001).

[14] Nagata Hidek, China. Patent JP2001169991. ( 2001).

[15] Zhiyuan Shen. TFT-LCD technology: structure, principle and manufacturing technology, Publishing house of electronics industry, Beijing , (2012).

[16] Qungang Ma, Principle and design of TFT-LCD, Electronic Industry Press, Beijing, (2011).

[17] Er Nie, Xingzhang Luo, Zheng Xing, LCD liquid crystal processing and indium recovery technology , J. Environmental Engineering, 9(2008)1251-1254.

[18] Jianli Li, Lianyou Li. From the vertical tank zinc smelting coke and dust recovery of indium process conditions optimization, J. China Nonferrous Metallurgy, 1(2007)112-115.

[19] Shunde Zheng, Recovery of indium and tim from waste ITO target, Central South University, Changsha, (2005).

[20] Dongsheng Xu, Recovery of indium and tim from waste ITO target, Beijing University of Chemical Technology, Beijing, (2008).