| 摘要: | 隨著5G通訊以及半導體產業的蓬勃發展，鎵金屬的需求日益漸增，也因此產生許多含氮化鎵之電子廢棄物，由於國內尚未有回收鎵金屬之成熟技術，且缺乏鎵資源，本模擬研究探討如何從含鎵電解液中回收鎵，並達到商業化之規模。
本研究以萃取劑改質樹脂(D2EHPA/XAD-4)從含鎵電解液中進行離子交換以回收鎵。模擬採用Aspen Plus之Chromatography模組進行研究開發，以extended Langmuir isotherm描述其等溫平衡吸附曲線，再以固相Linear lumped resistance質傳阻力模型描述其吸附質傳阻力。因等溫平衡吸附實驗與連續管柱實驗之操作方式不同，會影響其吸附效率，所以需要用吸附量修正因子(fads)修正兩種實驗之吸附量差異。再以模擬分別驗證純鎵離子溶液、純鋁離子溶液、純鎵離子加純鋁離子混合溶液、及實際浸漬廢料稀釋溶液實驗數據，求得符合程度最佳之各離子吸脫附質傳係數(MTC)與吸附量修正因子(fads)，以確認程式及參數的可靠度。
利用實驗設計分析探討當進料濃度為300 ppm Ga以及30 ppm Al時，填充樹脂高度、塔徑、吸附時間、脫附時間、吸附流量與脫附流量對鎵回收率、出口鎵濃度以及鋁對鎵重量比之影響，研究最適化以及符合商業化規模之操作條件，以回收較多之鎵金屬。變因探討後之最適化操作條件為填充樹脂高度78.69 cm、塔徑9.98 cm、吸附時間90.61 min、脫附時間341.62 min、吸附流量0.058 L/min、脫附流量0.058 L/min，樹脂重量為3060 g。此操作條件下可得鎵回收率89.97%、出口鎵濃度71.53 mg/L以及鋁對鎵重量比7.94%。最後，以上述之最適化操作條件模擬一根管柱每天可處理之鎵進料量，並以我國一年之鎵廢料相比較，計算出大約需要6根管柱，共18.36公斤之樹脂即可處理一年所產出之鎵廢料量。
;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. |
