Abstract
The metal-containing sludge generated from the printed circuit boards (PCBs) manufacturing has been recycled as a secondary resource of copper (Cu) rather than being treated as a hazardous solid waste. However, it should consider the complexity of processing and using of oxidizing or precipitation agents to dissolve and separate Cu from other impurities, especially iron (Fe). This study has combined the dissolution and separation step in one stage by integrated acid leaching and electrodeposition to simplify the recovery process, while maintaining the high efficiency of separation. The chemistry of acid leaching and electrodeposition of the metals demonstrated that the metals (Cu and Fe) in the sludge sample were dissolved in the H2SO4 electrolyte, and Cu could be selectively deposited on the cathode based on the different potential conditions to reduce it on the cathode. The important factors affecting the deposition of Cu were investigated, finding the optimal conditions (current density 15 mA/cm2, H2SO4 100 g/L, Cu 20 g/L, at 45 °C, and for 6 h) which could completely recover Cu from the electrolyte in a selective manner. The obtained copper product possessed a high purity of >99% with adequately uniform morphology and an acceptable consumption of energy (1.7 kWh/kg). It is an effective and simple approach to reclaim the value metal copper from the industrial waste in one single stage of integrated extraction and refining.
Highlights
The manufacturing of printed circuit boards (PCBs) involves a multi-stage process using a variety of organic and inorganic reagents, which releases a large amount of heavy metal-containing sludge from waste water and spent solutions after neutralization and sedimentation [1]
The sludge generated from PCBs manufacturing contains the major components such as copper (Cu) and iron (Fe)
The results show that the copper in the waste sludge is in the form of Cu(OH)2 and Cu metal, while Fe mainly presents as Fe(OH)3 and a minor amount of Fe(OH)2 [27]
Summary
The manufacturing of printed circuit boards (PCBs) involves a multi-stage process using a variety of organic and inorganic reagents, which releases a large amount of heavy metal-containing sludge from waste water and spent solutions after neutralization and sedimentation [1]. Hydrometallurgical processes are alternative methods to recover copper from Cu-bearing sludge by dissolution in a wide range of acid media such as HCl, HClO4, HNO3, or H2SO4 [6,7,8,9,10,11] These processes are not selective, as these strong acids dissolve several metals including the Cu and Fe contained in the sludge. Hydrometallurgical methods can ensure high efficiency of selective Cu recovery from the Cu-bearing sludge This approach appears to be complicated and is found to consume more chemicals due to the necessity of multi-stage leaching, in addition to adding oxidizing or precipitation agents. The integrated dissolution and the selective separation of Cu from Fe are described, along with the optimization of process parameters for Cu-electrodeposition the variation of current density, temperature, H2SO4, and total copper concentration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
