优化混合菌培养及废电路板添加促进铜的浸提

Optimization of Mixed Bacteria Culture and Addition of Waste Printed Circuit Board to Promote Copper Recovery

以嗜酸氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)和氧化硫硫杆菌(Acidithiobacillus thiooxidans)为出发菌株,优化混合菌培养及废弃印刷线路板(PCBs)粉末添加方式提高铜浸提效率。首先考察2种菌接种量对混合菌生长的影响;其次响应面优化混合菌培养液pH,硫酸亚铁(FeSO4·7H2O)和单质硫(S)浓度;最后采取多点添加策略提高PCBs添加量和铜浸取率。结果表明,混合菌培养最佳条件:嗜酸氧化亚铁硫杆菌与氧化硫硫杆菌接种量之比为1∶2,pH 1.56,FeSO4·7H2O和S为16.88和5.44 g/L;多点添加PCBs策略为:48 h添加量6.4 g/L,96 h添加量9.6 g/L,144 h添加量12.8 g/L。混合菌在此工艺条件下培养240 h后,铜浸取率高达92.6%。

This paper aimed to optimize mixed culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans and addition times and amounts of waste printed circuit boards(PCBs) powder for maximizing copper leaching percentage.Initially, influences of inoculums ratio between two acidophiles on their cells growth were studied by using hemocytometer counting method. Then, initial medium pH value and concentrations of FeSO4·7H2O and elemental sulfur(S) were optimized by response surface methodology(RSM). Finally, multiple-point PCBs addition was tested to determine maximal amounts.Optimal mixed culture conditions were initial inoculums ratio(A. ferrooxidans∶A. thiooxidans) 1∶2, culture medium pH 1.56,FeSO4·7H2O and S at 16.88 and 5.44 g/L. Multiple points of PCBs powder addition amounts and times were 6.4 g/L at 48 h,9.6 g/L at 96 h and 12.8 g/L at 144 h. Under optimal mixed culture condition, with PCBs addition 28.8 g/L in total, copper recovery reached 92.6% after 240 h cultivation.