溴 酸 钾-氨水化学退铜

Chemieal Stripping of Cu with KBrO_3-NH_3 H_3O

本文提出了不良铜镀层在KBrO_3作氧化剂的氯溶液中进行氧化还原反应的退除方法。该方法的优点是:溶液组成简单,操作容易,退除效率高(静置退除最高达45μ/cm^2h),成本低(溶解每克铜为0.036元),退除液再生和铜的回收容易。选定最佳工艺条件为:KBrO_3、25-35g/L,NH_3·H_2O(浓)180-250mL/L,NH_4Cl60-100g/L,室温(15-35℃)。铜在该退除液中的溶解过程可以认为分如下三步进行:1)铜被氧化为Cu^I,2)Cu^I或CuO与NH_3作用,形成可溶性无色络合物[Cu(NH_3)_2]^+;3)[Cu(NH_3)_2]^+或Cu^I进一步氧化,生成[Cu(HN_3)_4]^(2+)。此外,本文探讨了这一方法的机理、NH_3与NH_4Cl对铜溶解的作用、溶解反应的热效应与铜溶解时的pH变化。通过实验证明此退铜液对钢铁制品基体无影响,退镀的基体可直接重新复镀而获得结合力良好的镀层。

A method by which rejected Cu plate is stripped through a'redox in an ammonia solution with KBrO_3 as oxidizer. It has advantges of simple composition, easy operation, high effici- ency (static stripping 45/cm^2. h max), low cost (<￥0.036/g. Cu) and easy regeneration of the solution and Cu recovery. The optimum conditions are as fellows: KBrO_3 25-35g/L, NH_3.H_2O (concentrated) 180-250g/L, NH_4Cl 60-100g/L, room temperature. Copper dissolving in the solution can be considered to be performed in three steps: 1)Copper is oxdized to form CuI, 2) CuI and NH_3 are reacted to form [Cu(NH_3)_2]^+, and 3) [Cu(NH_3)_2]^+ is. oxidized to form [Cu(NH_3)_4]^(2+). In addition, the mechanism of the method, the effects of NH_3 and NH_4Cl on Cu dissolving, the heat effect of dissolving reaction on pH change during Cu dissolving are discussed. Expe- riments show that the solution has no effect eu iron and steel substrute. The stripped substrate can be replated with good adhesion. The regeneration of the solution and Cu recovery can be done with (NH_4)_2S or by electrolysis. The shortceming of the method is a little ammonia gas escaping out, which can be minimized by covering or venting.