Integrated process for recycling aluminum electrolytic capacitors from waste printed circuit boards: Disassembly, heat treatment and magnetic-eddy current-electrostatic separating

An aluminum electrolytic capacitor (AEC), mounted on a printed circuit board (PCB), is an integral part of any electronic product. Currently, a great many waste AECs are generated from almost all kinds of end-of-life electronic products. The waste AEC is hazardous waste because the electrolyte contained in it is toxic, demanding safe disposal. However, the recycling technology has been poorly developed. This article presented a novel attempt to deal with AECs disassembled from waste PCBs, including heat treatment, crushing, and multistage physical separations. Firstly, the electrolyte contained in waste AECs was removed by heat treatment. Secondly, the residue was crushed to liberate metals (aluminum and iron) from nonmetals, and the pins (iron) were magnetically separated from other substances. Thirdly, the remaining components were sieved, and the particles with the particle size >1.6 mm were subjected to eddy current separation, and the particles with the particle size <1.6 mm were subjected to electrostatic separation. Finally, an integrated recycling process was developed based on the above studies. Under the optimum conditions, the total separation efficiency and the grade of aluminum were 87.9% and 98.25%, respectively. This study provides a feasible method for waste AECs recycling in an efficient and environmentally way. (C) 2017 Elsevier Ltd. All rights reserved.