Copper recovery from waste printed circuit boards by NH3−(NH4)2S2O8–CuSO4 slurry electrolysis

Chemically Benign Electrometallurgical Treatment of Waste-Printed Circuit Board in Polyethylene Glycol for Metal Recovery

“…31 The use of slurry electrolysis (SE) to recover metals from WEEE has been investigated on various metals, including Cu, Fe, Zn, Pb, Ag, Mn, and Au. 32,33 However, conventional SE practice requires a highly acidic, alkaline, or oxidative environment, such as 4 mol L −1 HCl, 34 190 36 1 mol L −1 (NH 4 ) 2 S 2 O 8 , 37 glycine, 38 and some of the mixed ionic liquid solution being used as the electrolyte (H 2 SO 4 and [MIm]HSO 4 ), 39 to facilitate the metal leaching from WPCB composite and prevent the metal ions from precipitating as electrochemically inert metal (hydro)oxide. Besides strong acids, organic solvent systems were 41 Our group recently reported the use of ethylene glycol (EG) as the main solvent for electrochemical leaching and recovery of metals from powdered WPCBs, 42,43 and He et al also has reported that EG could strengthen the stability of H 2 O 2 , which is better for Cu leaching.…”

“…Ideally, the process should be powered by electrical energy to be integrated with a renewable energy grid potentially . The use of slurry electrolysis (SE) to recover metals from WEEE has been investigated on various metals, including Cu, Fe, Zn, Pb, Ag, Mn, and Au. , However, conventional SE practice requires a highly acidic, alkaline, or oxidative environment, such as 4 mol L –1 HCl, 190 g L –1 H 2 SO 4 , 30 g L –1 H 2 O 2 , 0.25 mol L –1 (NH 4 ) 2 CO 3 , 4 mol L –1 NH 3 ·H 2 O, 1 mol L –1 (NH 4 ) 2 S 2 O 8 , glycine, and some of the mixed ionic liquid solution being used as the electrolyte (H 2 SO 4 and [MIm]­HSO 4 ), to facilitate the metal leaching from WPCB composite and prevent the metal ions from precipitating as electrochemically inert metal (hydro)­oxide. Besides strong acids, organic solvent systems were sometimes employed as a medium to induce metal leaching.…”