應用置換法於實廠處理醫療電子印刷電路板硫酸銅廢液

Application of Cementation Technology in Treation Copper-Bearing Waste from Micro-etching Processes of Medical Electronics Printed Circuit Board

本研究針對醫療電子印刷電路板微蝕刻製程所產出的硫酸銅廢液，應用銅-鐵置換技術進行資源化處理，評估初始銅濃度和pH值對反應速率的影響。結果發現銅初始濃度值分別是15、23、30 g/L時，反應循一階動力式進行，但反應速率均隨銅離子的初始濃度增加而遞減。另以四組pH值(pH=1~4)進行試驗，發現pH=4之銅離子置換率較其他3組降低約40%，推測當溶液pH增加時，鐵片表面因氫氧化銅大量沉積而形成鈍化現象，鐵片表面活性面積減少，導致置換反應減緩且因無法有效釋出電子，以離子型態進入電雙層往外擴散，置換率因此受到化學反應所限制。本試驗以三組pH值(pH=1~3)進行質量平衡估算，結果發現總投入量和總產出量之合計相等，符合實驗預期，不過資源轉換率平均值僅58.7%，建議未來應於製程上進行改善，藉由減少置換槽的清洗耗水量或藉由廢水回收再利用於製程中，以提升資源轉換率。

A coper-bearing waste generated from the micro-etching process of medical electronics printed circuit board (PCB) was studied by iron cementation technology in a practical chemical plant. Operation parameters include initial copper ion concentrations (15, 23, 30 g/L) and pH values (pH = 1, 2, 3, 4) were assessed. Results showed that, within the range from 15 to 30 g/L of coper ion concentration, the reaction rate decreased with increasing the initial concentration. In addition, the higher the pH value the slower the copper cementation rate. And at pH= 4, the rate is as low as about 40 %, compared to the other pH values.