带元件废印刷线路板中金的回收工艺

Gold-recovering process from waste printed circuit boards(PCBs) with components

带元件的废印刷线路板多种金属共存,在采用氰化法浸取金的过程中,金的质量浓度随浸取时间的变化呈先升高后降低的曲线特征。如果反应时间控制不当,已经溶解的金就会被废印刷线路板上锌、镍等金属还原。为了提高金的回收率,研究了低氰化物质量浓度、短浸出时间的两次逆流浸金工艺,使金的回收率达到99%以上,废印刷线路板表层残余Au品位在3 g/t以下。

Several kinds of metals exist in waste printed circuit boards（PCBs） with component.So during the recovering process of cyanide leaching aurum from PCBs,aurum concentration increases at first and then decreases as leaching proceeds.If the leaching time is not well controlled,aurum already leached from PCBs will be deoxidized by zinc and nickel on the board.In order to reclaim more aurum,a leaching process with twice refluence at low cyanide concentration and short leaching time was studied.Experimental results showed that leaching rate of aurum could be above 99 % and the aurum in remainder PCB surface was less than 3 g/t.