Sheng Peter P, Etsell Thomas H
Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada.
Waste Manag Res. 2007 Aug;25(4):380-3. doi: 10.1177/0734242X07076946.
Computer circuit board scrap was first treated with one part concentrated nitric acid and two parts water at 70 degrees C for 1 h. This step dissolved the base metals, thereby liberating the chips from the boards. After solid-liquid separation, the chips, intermixed with some metallic flakes and tin oxide precipitate, were mechanically crushed to liberate the base and precious metals contained within the protective plastic or ceramic chip cases. The base metals in this crushed product were dissolved by leaching again with the same type of nitric acid-water solution. The remaining solid constituents, crushed chips and resin, plus solid particles of gold, were leached with aqua regia at various times and temperatures. Gold was precipitated from the leachate with ferrous sulphate.
计算机电路板废料首先在70摄氏度下用一份浓硝酸和两份水进行处理1小时。这一步溶解了贱金属，从而将芯片从电路板上分离出来。固液分离后，与一些金属薄片和氧化锡沉淀物混合的芯片被机械粉碎，以释放保护塑料或陶瓷芯片外壳内所含的贱金属和贵金属。该粉碎产物中的贱金属通过再次用相同类型的硝酸-水溶液浸出而溶解。剩余的固体成分，粉碎的芯片和树脂，加上金的固体颗粒，在不同的时间和温度下用王水浸出。金从浸出液中用硫酸亚铁沉淀出来。
