- 學位論文
以具分散反萃取相支撐式液膜分離回收廢液晶面板內銦(In3+)離子之研究
Separation and Recovery of In3+ Ions from discarded LCD by Supported Liquid Membrane with Strip Dispersion
摘要
摘要 本研究使用具分散反萃取相支撐式液膜（Supported Liquid Membrane with Strip Dispersion，SLMSD），利用中空纖維膜（hollow fiber module）以兩步驟程序回收與純 化濃縮廢液晶面板內之銦金屬。近年來液晶顯示器（Liquid Crystal Display，LCD）具有 重量輕、厚度薄、體積小且解析度高等優點，因此廣泛應用在各類光電產品中。銦錫氧 化物（Indium Tin oxide，ITO）為鍍濺於液晶面板表層之透明電極，其中稀有金屬銦之 價格近年來波動劇烈，且隨著廢棄液晶顯示器日益增多，故銦金屬之回收與純化濃縮所 帶來的經濟效益不容小覷。 根據全量分析結果顯示，廢液晶面板之銦金屬含量約 0.35-0.38mg In/g LCD，酸浸 結果受粒徑大小、固液比、酸液濃度與酸浸漬時間影響；實驗結果顯示，以粒徑 100 μm、 3N HCl 酸浸漬液、固液比 25g LCD/50 ml HCL 與反應時間 30 分鐘可以獲得最佳酸浸漬 結果，酸浸溶蝕效率約 70%。根據批次實驗結果，當萃取劑（D 2 EHPA）濃度由 0.05 M 上升至 0.25 M，銦離子的萃取效率由 50%上升至 98%，此外 2N HCl 可以有效將銦離子 從 D 2 EHPA 中與其他離子分離並反萃取至水相溶液中，整體回收率約 85%，濃縮程度約 4.5 倍。 本研究根據批次實驗結果設定 SLMSD 之最佳操作參數，酸浸漬液中的銦離子濃度 為140.9mg In/L，相當於0.28mg In/g LCD；銦離子回收濃度與回收效率隨反應時間上升， 但純度隨時間增加而下降。反應時間 5 分鐘至 60 分鐘，銦離子自酸浸漬液中的回收濃 度由 273.6mg In/L 提升至 709.8mg In/L，之後再下降至 614mg In/L、回收效率由 58.9% 上升至 98.7%，濃縮程度為 1.9 倍到 5 倍之間；銦離子之純度介於 71%至 21.2%之間。 在此操作條件下，本研究綜合銦離子之回收純度、濃縮程度以及回收效率，以操作 10 分鐘為最佳模場操作時間，回收純度為 71%、濃縮程度為 4 倍、回收效率為 81.3%。
並列摘要
Abstract As a consequence of economically important and limited resource, material recovery has received a great attention from researcher. This paper describes the feasibility to separate and recover indium from different fraction of discarded LCD manufacture by a supported liquid membrane with strip dispersion (SLMSD) technique. The experiments were divided into 3 steps as follows: (i) Optimization of the operating parameters i.e. pH, contact time, particle size and solid-liquid ratio (S/L) for solid extraction (leaching study). (ii) Liquid-liquid batch extraction where the effects of acid extractant (di-ethylhexyl phosphoric acid; D 2 EHPA), organic solvents Isopar-L and commercial diluent modified 1 –dodecanol were investigated for the extraction performance of indium. (iii) Operation of the supported liquid membrane with strip dispersion (SLMSD). The results indicate that the maximum indium contained in the LCD was around 0.35-0.38 mg In/g solid. The performance of solid extraction was related to the particle size, S/L ratio, acid concentration and contact time. The highest yield of indium extracted from LCD was 207 mg/L with the particle size of 100 um, S/L of 1 g of solid per 2 ml of 3NHCl under extraction time of 60 min. In the liquid-liquid extraction, indium extraction was strongly dependent on the concentration of D 2 EHPA as increasing its concentration from 0.025 to 0.25 M, indium extraction increased from 50% to 98%. At the concentration beyond this level, the extraction efficiency remained constant. In addition, HCl was very efficient to separate indium from D 2 EHPA phase. The operation of SLMSD was performed under the optimum condition obtained from the batch experiment. The results indicate the indium contained in the feed was efficient to extract in the hollow fiber membrane. The Indium in the recovery efficiency achieved 81.3%、the concentration ratio achieved around 4 and the impurity less than 30% in 10 minutes operation time. The results obtained from this experiment were in good agreement with the batch study. This demonstrates the SLMSD has a potential use for material recovery.