Material port fractal of fragmentation of waste printed circuit boards (WPCBs) by high-voltage pulse

Crushing is the key to recycling waste circuit boards, the precondition of separation. Crushing the metal and nonmetal components of a circuit board allows the separation of the nonmetal components. As the number of electrical pulses rises, the number of particles bigger than 2 mm decreases, and the number of particles smaller than 2 mm increases. The same happens when the number of pulses is invariant but the voltage is increasing. Particles smaller than 2 mm do not allow the possibility of secondary crushing. We propose a model to establish the pulse operational conditions for achieving the optimal rate of copper content distribution (-1.5 + 0.5 mm). Based on fractal theory and particle morphology, a program for calculating the fractal dimensions of WPCB ports is compiled. It is thought that the fractal dimension is related to the complexity of the fractures of the materials and the particle shapes. The more complex the fractures or particle shapes, the bigger is the calculated fractal dimension. (C) 2014 Elsevier B.V. All rights reserved.