重选—磨细—酸浸联合工艺回收PCB中金属的研究

Study on Recycling Metal in PCB by Heavy Medium Selection—Selectivity Milling—Acid Lixiviating Process

采用重介质分选选择性磨细酸浸联合工艺,利用磁铁矿重介质悬浮液,对粗碎后的PCB进行分选,再利用PCB中不同塑料可磨性的不同,将其进行选择性磨细,使PCB中所含金属成分与其他组分有效分离,采用酸浸工艺将各种金属成分转移到液相中,实现金属成分的高效回收。结果表明,在PCB的粒度小于等于2.5mm时,可使PCB中约55.26%的金属得到富集;86.08%的Au和89.21%的Ag被富集到磨细的粉末中,产品中的各种金属含量分别为:Au0.68kg/t,Ag0.91kg/t,Cu120.8kg/t,Al2.98kg/t,Sn28.02kg/t。当采用350mL浓H2SO4、浸出时间为8h,浸出温度为100℃条件下,对50g分选后的重组分进行酸浸时,可以使Au的回收率达到89.8%,Ag的回收率达到90.2%。与其他传统工艺相比,该工艺具有回收效率高、低污染、低能耗等特点,可以作为PCBs资源化的有效手段。

This paper used heavy medium selection-selectivity milling-acid lixiviating process to recycle metal in PCBs.It used magnetite as the heavy medium,selected PCB after the coarse fragmentation,selectivity milled the PCB according to the different milling characteristics to separate the metal from other component,then,by acid lixiviating to transfer the metal into liquid phase,recycled the metal efficiently.As a result,separate efficiency could reach 55.26％ when the PCB′s granularity was less than or equal to 2.5 mm; 86.08％ of Au,89.21％ of Ag were enriched into the powder after the selectivity milling process,and the contents of metals in the powder were Au 0.68 kg/t,Ag 0.91 kg/t,Cu120.8 kg/t,Al2.98 kg/t and Sn28.02 kg/t,respectively.Under the conditions of oil of vitriol350 mL,lixiviated time 8 h,lixiviated temperature 100 ℃,the recycle ratios of Au and Ag in 50g selected heavier part were 89.8％ and 90.2％,respectively.Compared with traditional processes,the heavy medium selection-selectivity milling-acid lixiviating process had the characteristics of high recycle ratio,low pollution,low energy consumption,etc.,which could realize PCBs reclamation.