The stripping effect of using high voltage electrical pulses breakage for waste printed circuit boards

In this study, high voltage electrical pulses were utilized to process waste printed circuit boards to cost effectively liberate metal and nonmetal materials. Relative mass omega(i) and particles content eta(i)indexes were defined to assess the stripping effect produced by high voltage electrical pulses breakage. For relative mass level in the 0-10% range, in the -6+3 mm fraction, particles content accounted for 84.84% of the total particles, while the mechanical crushing only occupied 8.84%. Voltage and pulse experiments were carried out to investigate the crushing effect of high voltage electrical pulse breakage for printed circuit boards. It was found that when the voltage and pulse number was at 160 kV and 300, the stripping rate of copper was 98.56% and 92.58% in the -25+13 mm fraction respectively. The measured bending strength of the material revealed the selective crushing effect of high voltage electrical pulses in the different material interfaces. A liberation mechanism was elaborated by using the energy band theory, and a process model was utilized to reveal the mode of crushing. Furthermore, the microscopic appearance of the resulting product confirmed that copper underwent high-temperature melting, while the resin was decomposed during the crushing process. Compared to conventional mechanical crushing process, high voltage electrical pulses can better liberate metal-bearing than mechanical comminution technology. (C) 2018 Elsevier Ltd. All rights reserved.