氨基磺磺酸法剥离废印刷线路板表面镀金层的研究

Recovery of Gold on Surface of Waste Printed Circuit Boards by Sulfaminic Acid

含有贵金属金的废弃印刷线路板有较高回收价值。采用氨基磺酸腐蚀法,浸出镀金层下的铜和镍,回收得到金箔。探索氨基磺酸法回收金的最佳工艺条件,研究结果表明:常温条件下,取内存条与氨基磺酸溶液的固液比(g/mL) 1:5,双氧水体积分数15%,氨基磺酸浓度70 g/L,废旧内存条浸出时间120 min (不同类型板因镀层差异剥落时间稍有差异),此工艺条件下金的回收率可以达到96%以上。氨基磺酸腐蚀法对金的回收选择性好,剥离的金箔可直接熔炼,脱金后的线路板可用于回收其他金属和非金属;溶液回收铜镍后,可循环使用,实现回收过程中的闭路循环,减轻环境污染。

Wasted printed circuit boards with precious metal of gold have high recovery value. With the technique of sulfaminic acid etching, copper and nickel undered the gold plate were leached and then the gold foil could be collected. The optimum conditions of sulfaminic acid etching technique were explored. The results show that at room temperature, when the solid-liquid ratio (g/mL) of the wasted memory stick and sulfaminic acid is 1 : 5, the recovery rate of gold may be up to 96% with 15% hydrogen peroxide by volume, 70 g/L sulfaminic acid concentration and 120 min soaking time of wasted memory sticks (the coating flaking time varied slightly due to the type difference of plates). In addition, it has a good selectivity for element Au, the stripped gold can be melted directly while the treated printed circuit boards can be used for recovering other metal or nonmetal, and the solution can also be recycled after recovering copper and nickel, which would realize the closed circulation in recycling process and reduce environmental pollution.