| dc.description.abstract | With the advance of semi-conductor industry and 5G communication, the demand for gallium metal is increasing, and a great amount of industrial waste material, such as scraped GaN-containing wafer, has been produced. Due to the shortage of Ga resources and the current lack of ability to recycle Ga metal in Taiwan, a commercial Ga recycling process had been developed in this simulation study.
In this work, extractant-modified resin (D2EHPA/XAD-4) had been used to recycle Ga ions from the electrolyte which containing Ga ions. The Chromatography module of Aspen Plus software was adopted in this research. The isothermal adsorption curve was fitted by extended Langmuir isotherm model while adsorption mass transfer resistance was modeled by Linear Lumped Resistance model. Due to the difference of operating method between isothermal adsorption experiments and ion exchange experiments which may affect the adsorption efficiency, the adsorption correction factor (fads) was estimated by the adsorption capacity difference between two experiments. The simulation of ion exchange experiments of pure Ga3+ solution, pure Al3+ solution, mixture of Ga3+ and Al3+ solution, and real waste dilute solution have been developed and fitted to the experimental data. The mass transfer coefficient and adsorption correction factor could be found by fitting the ion exchange experiments. In order to obtain the higher recovery of Ga, higher concentration of Ga, and lower Al to Ga weight ratio, several variables were discussed to find the best operating conditions in the commercial process. The finial operating conditions are: height of resin layer 78.69 cm, bed diameter 9.98 cm, adsorption time 90.61 min, desorption time 341.62 min, adsorption flow rate 0.058 L/min, and desorption flow rate 0.058 L/min. The simulation results are 89.97% recovery of Ga, 71.53 mg/L concentration of Ga, 7.94% Al to Ga weight ratio, and using 3060 g resin. Finally, we need about 6 beds to process the scraped GaN-containing wafer produced per year in Taiwan. | en_US |