Enhanced bioleaching efficiency of copper from printed circuit boards without iron loss |
Wang, SH (Wang, Shuhua); Chen, LX (Chen, Lixiang); Zhou, XL (Zhou, Xiuli); Yan, WF (Yan, Weifu); Ding, R (Ding, Rui); Chen, BL (Chen, Bilian); Wang, CT (Wang, Chin-Tsan); Zhao, F* (Zhao, Feng) |
To solve the common problem of Cu bioleaching from waste printed circuit boards (PCBs), a slightly modified bioleaching method was used in this work. This method was concentrated on preventing the iron loss, which would promote Cu bioleaching, reduce FeSO4·7H2O consumption from up to 60 g/L and bring cost savings. Herein, we firstly compared the bioleaching performances between 1.5SO42- system and 1.5S0 system. The results showed that 1.5S0 system was practicable to inhibit the production of Fe(III)-precipitates, and the sustaining low pH should be the main factor for the suppression. Then, different initial content of FeSO4·7H2O was combined with multi-stage bioleaching mode under 1.5S0 system. It was found that 0.25 g/L FeSO4·7H2O was sufficient for bioleaching of Cu from 50 g/L PCBs, the increasing Cu2+ content was achieved by the unsuppressed circulation between Fe2+ and Fe3+. Compared to previous reports, the input quantity of FeSO4·7H2O was reduced remarkably (up to 239 times) and the capital cost of bioleaching could be saved by 37–284 USD m-3. Hence, this work significantly promoted the Cu bioleaching performance through controlling the iron loss, which appears very promising for the development of practical applications. Concentrations of Fe2+ (a), Total Fe (b), pH (c) and Cu bioleaching efficiency (d) with respect to time under two bioleaching systems (experimental conditions: pH=1.5; 22g/L FeSO4·7H2O for 1.5SO42-; 8 g/L FeSO4·7H2O for 1.5S0; 10 g/L PCBs). |
Key words:Bioleaching; Electronic wastes; Printed circuit boards; Acidophilic bacteria; Jarosite |
Volume:180 Page:65-71 Journal:HYDROMETALLURGY |
https://doi.org/10.1016/j.hydromet.2018.07.010
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