Recovery of Gallium from Simulated GaAs Waste Etching Solutions by Solvent Extraction

Wei-Sheng Chen, Ko-Wei Tien, Li-Pang Wang, Cheng-Han Lee and Yi-Fan Chung
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Wei-Sheng Chen: Department of Resources Engineering, National Cheng Kung University, Tainan 701, Taiwan
Ko-Wei Tien: Department of Resources Engineering, National Cheng Kung University, Tainan 701, Taiwan
Li-Pang Wang: Institute of Environmental Engineering and Management, National Taipei University of Technology, Taipei 106, Taiwan
Cheng-Han Lee: Department of Resources Engineering, National Cheng Kung University, Tainan 701, Taiwan
Yi-Fan Chung: Department of Resources Engineering, National Cheng Kung University, Tainan 701, Taiwan

Sustainability, 2020, vol. 12, issue 5, 1-10

Abstract: Gallium arsenide is used in semiconductor industries worldwide. Numerous waste etching solutions are produced during the processes of GaAs wafer production. Therefore, a complete and eco-friendly technology should be established to recover gallium as a gallium chloride solution and remove arsenic ion from waste GaAs etching solution. In this study, the gallium trichloride and arsenic trisulfide powders were dissolved in ammonia solutions to prepare the simulated solutions, and the pH value was adjusted to pH 2 by nitric acid. In the extraction step, the GaAs etching solutions were extracted using 0.5 M Cyanex 272 solutions in kerosene at pH 2 and 0.1 O/A ratio for 5 min. The extraction efficiency attained 77.4%, which had an optimal ratio of concentration, and the four steps extraction efficiency attained 99.5%. After extraction, iron sulfate heptahydrates were added into the raffinate, and the arsenic ions were precipitated. The removed rate attained 99.9% when the Fe/As ratio was 10. In the stripping step, the organic phase was stripped with 0.5 M hydrochloric acid at 1 O/A ratio for 3 min, and 97.5% gallium was stripped. Finally, the purity of gallium chloride solution was 99.95% and the gallium was seven times the concentration of the etching solutions.

Keywords: gallium arsenide; Cyanex 272; bis(2,4,4-trimethylpentyl) phosphinic acid; arsenic precipitation (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2020
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