Recycling Technology for Metal Resources: Investigation of Liberation Technology for Tantalum Recovery from Spent Printed Circuit Board

Abstract

An appropriate comminution for liberation of target materials from secondary resources is very important to achieve an energy saving recycling system with high separation efficiency. For tantalum (Ta) recovery from printed circuit boards (PCBs) in waste electric and electronic equipments (WEEEs), parts detachment from PCBs, which means disintegration of parts from the board without pulverization of them, is effective because Ta is generally used in a specific part on the board, that is, “tantalum capacitor”. High Ta concentrate was achieved by comminution using drum-typed agitation mill and chain-type agitator was better than rigid-type agitator. To reveal the mechanism of breakage phenomena in comminution/detachment process of PCBs, computer simulation using discrete element method (DEM) was carried out. Comminution test was conducted using simulant PCBs with solder-mounted capacitors and compared to simulation results in which the shape of simulant PCBs and chain of the agitator was represented using particle-based rigid body model. Simulation results suggested that chain-typed agitator mill promotes inter-action between a board and another board which is most important mechanism for parts detachment from the boards, because the chain could give wide variety of energy to boards due to their deformation.

Graphical Abstract