化學置換法是由氯化銅蝕刻廢液中回收金屬銅最經濟有效的技術，反應後之回收液，亦可進一步製成混凝劑。本研究依據實際氯化銅廢液之性質，並以金屬鋁為犧牲金屬，進行批次實驗，再以操作反應溫度變化、銅回收率和反應時間、銅粉純度及回收液品質為評估指標，建立合適之操作方式。 研究發現，以鋁為犧牲金屬之置換反應，在一次添加足量鋁金屬時，初始銅離子濃度越高，回收速率越快，但會造成溫度於反應5分鐘內超過95℃，影響操作上的安全性，尤以初始銅離子濃度大於60g/L以上時，最為顯著。因此，若要避免操作上的危險性，使銅離子完全置換，勢必將足量鋁金屬，採取分批添加的方式。此外本研究發現，增加犧牲金屬鋁劑量(Al/Cu0莫耳比)及縮小鋁片尺寸大小，均有助於提升置換反應速率，但亦增加了旁反應對鋁金屬的消耗率，且旁反應對鋁之消耗量，將高於主反應。 綜合研究評估結果顯示，當初始銅離子濃度(Cu0)分別介於30~50及50~60g/L之間，且鋁總劑量Al/Cu0莫耳比分別為1.0及1.33時，採分批添加方式，經75分鐘反應時間，均可達到99％以上銅回收率，銅粉純度約為95~99%。 Cementation is one of effective and economic techniques for recovery of metal copper from wasted etching liquid containing copper chloride. Also, after solid/liquid separation, the supernatant can be recovered and reused as coagulant. In this study, batch operation of cementation was employed to test the feasibility of copper recovery from real wasted etching liquid using wasted material of aluminum sheet as the sacrificed metal. Several indicators, such as temperature variation, copper recovery rate and reaction time, purity of copper powder, and quality of the recovered supernatant, were used to evaluate the performance of cementation operation. Experimental results showed that once adding enough amounts of sacrificed metal aluminum, the copper recovery rate increased with the increase of initial copper concentration presented in etching liquid. However, this also resulted in raising temperature over 95℃ at the first 5 min of reaction time and affecting the safety of operation, especially, in the case of copper ion concentration was greater than 60 g/L. In order to avoid the danger of operation, sequencing replenishment of metal aluminum is preferable. This study also found that increase the molar ratio of Al/Cu0 or decrease the sheet size of metal aluminum added could enhance the cementation rate, but the side reaction would consume more aluminum than main reaction did. Based on the results of overall performance evaluation, when the initial copper concentration (Cu0) was in the range of 30~50 or 50~60 g/L and the total sequencing replenishment of aluminum added at Al/Cu0 molar ratio was 1.0 or 1.3, respectively, over 99% copper was recovered from solution and 95 to 99% purity of copper powder were obtained in 75 minutes of reaction time.
