电镀酸锡废水中不同金属离子的分离工艺

Separation process of different metal ions in acid tin electroplating wastewater

利用各种金属离子形成氢氧化物沉淀时pH的不同,从而实现电镀酸锡废水中各金属离子的分离与回收。原废水的pH为0.45,其中含锡137.3mg/L、Ni46.1mg/L、Fe11.4mg/L、Co8.6mg/L。先用10%的氢氧化钠溶液调节废水的pH为4.7,废水中的锡元素形成氢氧化亚锡沉淀;分离锡元素后的废水用10%的双氧水把其中的亚铁完全氧化成三价铁,再调节废水的pH至4.1,以除去铁元素;在分离了铁元素的废水中加入10%的次氯酸钠溶液,把其中的二价钴完全转化成三价钴,再调节废水pH为5~6,以分离钴元素;调节除钴后废水的pH为9.5沉淀其中的镍元素。

The separation and reclaiming of various metal ions from acid tin plating wastewater were achieved based on the fact that different metal ions form hydroxide precipitates at different pHs. The influent has a pH of 0.45 and contains Sn 137.3 rag/L, Ni 46.1 mg/L, Fe 11.4 mg/L, and Co 8.6 mg/L. Sn was precipitated as Sn（OH）2 by adjusting the influent pH to 4.7 with 10% NaOH solution. Fe was removed from the Sn-free wastewater via oxidation of Fe（Ⅱ） to Fe（Ⅲ） with 10% H202 followed by adjusting the pH to 4.1. Co was then separated from the wastewater without Sn and Fe after adding 10% NaC10 to oxidize Co（II completely to Co（III） and adjusting the pH to 5-6 successively. Ni was finally precipitated from the wastewater by adiusting the pH to 9.5.