NH_3-(NH_4)_2SO_4体系浸析PCB污泥中铜的研究

Study on the leaching of copper by the NH_3-(NH_4)_2SO_4 system from sludge produced in PCB industry

利用NH3-(NH4)2SO4体系,对印刷电路板(printed circuit boards,PCB)生产过程中产生大量的含铜污泥中的铜进行浸析。对PCB污泥中重金属的质量分数进行了测定,其中铜在污泥中的质量分数为33.500%,其余金属质量分数较小。重点探讨了氨-硫酸铵浓度及pH、浸析时间、液固比、温度等条件对浸析率的影响。NH3-(NH4)2SO4体系对PCB污泥中铜浸析的最优条件为氨、硫酸铵浓度分别为3.0mol/L和1.5mol/L,液固比为20mL/g,浸析时间为180min,浸析温度为25℃。在最优条件下进行了浸析应用试验,结果表明铜的浸析率可达到97.5%,此方法的相对标准偏差(relative standard deviation,RSD)为0.63%。

Copper sludge is produced during the production of printed circuit boards.The leaching of copper from the sludge by the NH3-（NH4）2SO4 system was studied.First,the mass contents of heavy metals in the sludge were determined.With few contents of other metals,the content of copper was 33.500%.The effect of concentrations of NH3-（NH4）2SO4,pH,leaching time,liquid/solid ratio and temperature were investigated.The optimum leaching conditions were found when the ammonia/ammonium sulfate concentrations were 3.0 mol/L and 1.5 mol/L,the leaching time was 180 min,the liquid/solid ratio was 20 mL/g,and the temperature was 25 ℃.Under these conditions,about 97.5% of the copper was effectively leached,and the relative standard deviation（RSD）was 0.63%.