Papers by Author: Chen Long Duan

Abstract: On the basis of introducing the latest research status of processing methods of waste printed circuit boards, the physical mechanism of eddy current separation was explained, and the component configuration of eddy current separator was described. A series of single-factor and orthogonal experiments were carried out to prove the separation effect of multiple metals with eddy current separator. The result indicates that the separation efficiency of above 92.0% and concentrate grade of above 95.0% can be obtained in the recycling of aluminum and brass with the delivery rate of 20~40%, rotate speed of rotor of 5~15Hz and belt speed of 7~9Hz.

Abstract: Comminution is a key part of the reutilization of discarded circuit board. In order to find out the most appropriate method of crushing, the characteristics of the materials and the mechanical properties of resistance impact of discarded circuit boards were studied. The substrate of circuit boards, slots of ISA and PCI were adopted as the specimen. The scanning electron microscope (SEM) and energy disperse X-ray spectroscopy (EDX) were used to characterize and analyze the combined state of the fracturing materials on the specimen surfaces after comminution. Results showed that the metals and nonmetals in the slots were crushed and dissociated easily.At the same time, the metal and nonmetal combined interfaces in the substrate have a trend to be broken and separated under the impact effect, which means the crushing circuit board has a favorable break effect under impact load.

Abstract: The reutilization of waste Printed Circuit Boards (PCB) is a focused topic in the field of environment protection and resource recycling, and the crushing is the crucial process for recycling waste PCB. A hamper impacting crusher was used to achieve metals crushing liberation from non-metals, the liberation mechanism of PCB can be explained by dispersion liberation accompanied disengaging liberation. The Rosin-Rammler distribution model of crushed PCB particle was put forward. The evaluation indexes show that Rosin-Rammler function can accurately describe size distribution of PCB particles because the convergence property R2 is 0.99694 and fitting error E is 4.80658. The selective crushing is appearance with metals concentrated in coarser fraction and non-metals in finer size during comminution processing. The impact crushing is an effective method to metals liberation of PCB particles.