Preparation of indium oxide from waste indium tin oxide targets by oxalic acid

Koo, Su-Jin; Ju, Chang-Sik

doi:10.1007/s11814-017-0231-x

Cited by 3 publications

(1 citation statement)

References 8 publications

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“…Reductive leaching of gallium from zinc residue has been reported by Wu et al [23], where quantitative leaching of gallium using SO 2 and H 2 SO 4 as lixiviant has been reported. Furthermore, recovery of indium and (or) gallium through hydrometallurgical technique from thin-film solar panel [24], zinc sulfide concentrate [25], copper indium gallium diselenide [26], Indium Tin Oxide waste target [27] has also been reported.…”

Section: Introductionmentioning

confidence: 99%

Recycling the GaN Waste from LED Industry by Pressurized Leaching Method

Chen

Hsu

Wang

2018

Metals

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In recent years, with the increasing research and development of the light-emitting diode (LED) industry, which contains gallium nitride (GaN), it is expected that there will be a large amount of related wastes in the future. Gallium has an extremely high economic value, therefore, it is necessary to establish a recycling system for the GaN waste. However, GaN is a direct-gap semiconductor and with its high energy gap, high hardness, and high melting point, these make it difficult to recycle. Therefore, this study will analyze the physical characteristics of LED wastes containing GaN and carry out various leaching methods to leach the valuable metals from the waste optimally. Different acids are used to find out the best reagent for gallium leaching. Different experimental parameters are discussed, such as the effect of the different acid agents, concentration, pressure, liquid-solid mass ratio, temperature and time, which influence the leaching efficiency of gallium. Finally, acid leaching under high pressure is preferred to leach the GaN waste, and hydrochloric acid is used as the leaching solution because of its better leaching efficiency of gallium. Optimally, the leaching efficiency of gallium can reach 98%. by other materials/metals, and triggers global competitions to ensure steady supply [7]. According to a recent report published by the united nations environment program (UNEP), less than 1% of end-of-life (EOL) gallium and indium bearing materials are being recycled [2,3]. Gallium is used in a wide variety of products that have microelectronic components containing either gallium arsenide (GaAs) or gallium nitride (GaN) [5]. Due to the low solubility of nitrogen in gallium and the high vapor pressure of nitrogen on GaN, the native substrate of GaN is not available in large quantities. The GaN is a crystal of high bond energy that is equal to 7.72 eV/molecule, which results in higher melting temperature and good thermal stability [8,9]. The value of sales for the GaN power device market was expected to reach $178 million by 2015 at an annual growth rate of nearly 29 percent [10]. In 2012, imports of gallium and GaAs wafers, which were valued at about $32 million, continued to satisfy almost all U.S. demand for gallium. GaAs and GaN electronic components represented about 99 percent of domestic gallium consumption [5]. The value of worldwide GaAs device consumption increased by about 7% to $7.5 billion in 2015 owing to a growing wireless telecommunications infrastructure in Asia; growth of feature-rich, application-intensive, third-and fourth-generation (3G, 4G) "smartphones", which employ up to 10 times the amount of GaAs as standard cellular handsets; and robust use in military radar and communications applications. Cellular applications accounted for approximately 53% of total GaAs device revenue and wireless communications accounted for 27%. Various automotive, consumer, fiber-optic, and military applications accounted for the remaining revenue [11]. By yearend 2016, the GaN radio frequency device mar...

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