Facile and Cost-Effective Approach for Copper Recovery from Waste Printed Circuit Boards via a Sequential Mechanochemical/Leaching/Recrystallization Process

The recovery of copper (Cu-0) from waste printed circuit boards (WPCBs) is a great challenge as a result of its heterogeneous structural properties, with a mixture metals, epoxy resin, and fiberglass. In this study, a three-step sequential sequential process, including mechanochemical processing, water leaching, and recrystallization, for Cu-0 recovery from WPCB powder is reported. Potassium persulfate (K2S2O8), instead of acid/alkali reagents, was employed as the sole reagent in the cupric sulfate (CuSO4) regeneration process. Complete oxidation of Cu-0 in the WPCBs to copper oxide (CuO) and CuSO4 was first achieved during mechanochemical processing with K2S2O8 as the solid oxidant, and the K2S2O8 was simultaneously converted to sulfate compounds [K3H(SO4)(2)] via a solid solid reaction with epoxy resin (CnHmOy),) as the hydrogen donator under mechanical force. The rapid leaching of Cu species in the forms of CuO and CuSO4 was therefore easily realized with pure water as a nontoxic leaching reagent. The kinetics of the leaching process of Cu species was confirmed to follow the shrinking nucleus model controlled by solid-film diffusion. Finally, CuSO4 center dot 5H(2)O was successfully separated by cooling crystallization of the hot saturated solution of sulfate salt [K2Cu(SO4)(2)center dot 5H(2)O]. An efficient conversion of Cu-0 to CuSO4 center dot 5H(2)O product, for WPCB recycling, was therefore established.