高濃度酸鹼蝕刻廢液回收處理探討

Copper Recovery and Treatments of High Concentration Acidic and Alkaline Waste Solutions from Printed Circuit Board Industry

張農謙(Jung C.Chang)

指導教授 ： 林勝雄

元智大學/工程學院/化學工程與材料科學學系/碩士(2004年)

摘要

摘 要
目前台灣的PCB生產值僅次於美國日本位居全球第三位，印刷電路板業製程複雜，使用多種化學藥劑及特殊原料，因此排放的廢液污染物質種類繁多，並有高濃度的銅、鉛、鎳等重金屬，其中在蝕刻製程中所產生的酸鹼性蝕刻廢液的處理以往都是由代處理業回收處理。
本論文主要內容有三組實驗，第一組實驗是探討利用最傳統的酸鹼中和沉澱法，利用簡單的回收處理設備，簡單的處理程序，有效的將高濃度蝕刻廢液中的銅離子回收 98 %以上，處理過後的蝕刻廢液，可以再添加氯化銨及氨調配成蝕刻液，重複使用於蝕刻製程。
第二組實驗是將酸性蝕刻液用液鹼控制在不同的 pH 值及溫度，分析在不同 pH 、溫度過濾液體及銅泥中的銅含量及鐵、鉛、鎳等金屬含量。
第三組實驗是利用第一組高濃度酸鹼蝕刻廢液中和，取 pH 在 6 時的上澄液利用第二組實驗的結果，將 pH 控制在12，溫度控制在 95℃，就可回收第一組實驗剩下的銅，並且可以將上澄液的銅含量降低到 1 ppm以下達到排放水的標準。
以上三種回收處理方法雖然僅有簡單的酸鹼及溫度控制，但卻可以因應不同的需求，將高濃度含銅蝕刻廢液做一個妥善的處理，並且減少二次的環境污染。

關鍵字

蝕刻廢液回收

並列摘要

Abstract
Printed circuit board (PCB) production in Taiwan is currently ranked No. 3 worldwide, next only to the US and Japan. The PCB production is complex involves a number of specialty chemicals and materials, leading to many waste solid and liquid pollutants being discarded. Typical waste liquid solutions of a PCB plant from the etching processes contain high concentrations of many heavy metals, including copper, lead, nickel, etc. Disposal of these etching waste solutions is not easy and is usually done out of site by professional agencies.
The purpose of this research is to investigate the feasibility of utilizing the acidic and alkaline etching solutions for copper recovery. Three sets of experimental tests were performed in the present research. The first set was to test the neutralization process using alkaline and acid or acidic solutions. These tests focused on the pH optimization for maximum copper recovery. The test results indicated that very high copper recovery over 98% can be achieved as a solid product. Using ammonium chloride, the residual solution could be properly adjusted for recycle for etching reuse.
In the second test set, acidic etching solution was neutralized using sodium hydroxide at various pHs and temperatures. The recovered copper first appeared as copper hydroxide which was then converted copper oxide.
In the first test set, the residual solution still contained a significant amount of copper. It could be adjusted for ammonium context for recycle as etching agent. However, in the third test set, attempt was made to further recover the remaining copper in the residual solution by utilizing sodium chloride neutralization. Operating under the conditions of pH 12 and 95oC, the copper content in the residual waste solution could be further reduced from about 2,000 mg/l to below 1 mg/l, enabling discharge standard of the treated waste solution.

並列關鍵字

Copper Recovery

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