Materials Transactions Online

Materials Transactions, Vol.57 No.12 (2016) pp.2146-2152
© 2016 The Mining and Materials Processing Institute of Japan

Investigation of Part Detachment Process from Printed Circuit Boards for Effective Recycling Using Particle-Based Simulation

Yuki Tsunazawa1, Chiharu Tokoro2, Mitsuaki Matsuoka2, Shuji Owada2, Hiroyuki Tokuichi3, Masamichi Oida4 and Hirobumi Ohta5

1Mineral Resources Research Group, Institute for Geo-Resources and Environment, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8569, Japan
2Department of Resources and Environmental Engineering, Faculty of Science and Engineering, Waseda University, Tokyo 169-8555, Japan
3Miike Smelting Co., Ltd, Omuta 836-0017, Japan
4Copper Business Strategic Division, Mitsui Mining & Smelting Co., Ltd, Tokyo 141-8584, Japan
5Metals & Recycling Division, Metals Sector, Mitsui Mining & Smelting Co., Ltd, Tokyo 141-8584, Japan

For the establishment of appropriate recycling process, the delamination of electric components from printed circuit boards (PCBs), which are major components of e-waste, is expected, because some of useful critical metals are concentrated in specific components. However, the knowledge about the mechanism of the delamination process in a drum typed agitation mill is still limited and uncertain. To better comprehend the mechanism, in this study, the particle-based simulation and comminution tests using handmade PCBs were conducted. The behavior of PCBs and the air flow in the mill having flexible chains was simulated by the discrete element method (DEM) coupled with computational fluid dynamics (CFD). To model the shape of PCBs, the particle based rigid body model was introduced into the DEM. Since this model could not directly simulate the breakage phenomena, collision energy was calculated to qualitatively evaluate the comminution performance. In addition, the simulation results were compared with the experimental comminution tests. This study demonstrated the behavior of PCBs and the air flow in the mill, and the effect of the air to comminution process in the mill. It was also shown that the collision energy related to parts collision was better correlated with the experimental results and this correlation can be assumed using first order rate equation, which suggested part detachment was mainly brought by direct collision to parts in the mill.


(Received 2016/04/20; Accepted 2016/08/26; Published 2016/11/25)

Keywords: discrete element simulation, computational fluid dynamics, recycling, comminution, e-waste

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