鋁材表面處理廢液回收再利用之研究

Treatment of Waste Acid Liquid from Aluminum Surface Processing for Reuse

羅睦昌(Mu-Chang Lo)

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(1996年)

摘要

本研究之目的為利用離子交換薄膜透析及晶析法，針對鋁材表面處
理完之廢酸液進行處理以利回收再利用之研究；其回收之目的，主要在於
改善傳統中和處理排放法，回收硫酸，減少污泥產量，並可降低經營成本
。傳統的廢酸處理為利用液鹼、碳酸鈉或石灰石中和後，再排放澄清液，
此法造成大量污泥再予以掩埋。而污泥內殘存了大量的鋁酸鈉，不但增添
垃圾場負荷，污染地下水源，亦浪費相當的資源。擴散透析為利用Donna
現象，採用陰離子交換膜，藉離子強度和濃度差異分離電解質的作業，晶
析法是廢酸液於低溫情況下，添加氨水，造成溶液過飽和現象，致溶液內
之鋁離子與氨水合成為銨鋁明礬結晶。以上二法均為去除廢酸液內之鋁離
子，以使硫酸循環再使。本研究考慮各項實驗變數，以求得操作條件最佳
化。並以透析法處理過之脫酸液，再行結晶以降低液中之鋁離子及酸濃度
，本法與透析法結合併用，可降低末端脫酸液中和藥品費用69%，並可得
副產品銨鋁明礬90 g/l。

關鍵字

廢酸 ； 擴散透析 ； 晶析 ； 鋁離子 ； 銨鋁明礬 ； 回收再利用

並列摘要

Waste acid solution is produced in anodizing oxidation or
electroetchingoperation in the processing of aluminum products.
The conventional methodfor dealing with this waste acid is
simple neutralization. Such a processnot only still retains
certain adverse environmental impact, but wastesresource
matreials. The purpose of this research attempts to use ion
exchange diffusion dialysis and crystallization techniques in
recoveringsulfuric acid and other materials for possible reuse.
Diffusion dialysis isa relatively new technique based the
principle of Donna equilibrium. Ttuse ion exchange membranes to
separate electrolytes from the waste acid solution based on the
gradient and ionic strengthof the solution. Experimentswere
conducted to investigate the effects of numerous variables,
includingwaste acid and water flow rates, temperature, initial
acid and aluminumcontents, membrane surface area, number of
membrane assembly, etc., on thesystem performances. On the basis
of test results, optinal operating conditionswere determined and
recommended. The waste acid solution contains sufficientamount
of aluminum which can be recovered by the crystallization
process.Ammonium hydroxide was added to the waste acid solution.
When the temperatureof the mixture was become sufficiently low
and in the presence of very finealum seeds, alum crystals of
various size were formed rapidly and separated from solution.
Test runs were performed to examine the effects of
operationvariables on the crystal yields and compared with that
of commerical product.The pruity has been found to be extremely
high.

並列關鍵字

Waste acid ； Diffusion Dialysis ； Crystallization ； Aluminum Ion ； Aluminum Ammonium Sulfate ； Recovery for Reuse