Liberation Characteristics Assessment for Copper Component in PCB Comminution Product by Image Analysis

Abstract

Cu is one of the most valuable metals found in waste printed circuit boards (PCBs). In order to recover the metals from the e-waste, PCB recycling process exploiting physical concentration techniques have widely been applied. Size reduction steps including crushing and grinding are done for liberation of Cu from the non-metallic materials such as glass fiber and epoxy resin. Degree of liberation is an important factor by which liberation performance of comminution process is evaluated. The primary purpose of this study was to investigate liberation characteristics of Cu particles in comminuted PCB by using image analysis method. The analysis procedures include image processing such as noise reduction, edge detection and component discrimination so that a set of images of ground PCB particles provides quantitative information such as Cu grade distribution and degree of Cu liberation. The Cu liberation phenomenon was also discussed in terms of its disassociation behavior from non-metallic material and grindability difference.

Optimal Thermal Treatment for Effective Copper Recovery in Waste Printed Circuit Boards by Physical Separation: Influence of Temperature and Gas

“…Therefore, once liberated, it was comminuted rapidly [39]. Park et al [22] suggested that the comminution of objects consisting of two substances with mutually different ductilities shows the following behavior with a decrease in particle size.…”

“…PCB must be pulverized into particles to effectively liberate and separate Cu [18,21,22]. According to a previous study, it should be comminuted to approximately 150 µm or less (e.g., liberation size) [6,23,24].…”

Determination of Liberation Degree of Mechanically Processed Waste Printed Circuit Boards by Using the Digital Microscope and SEM-EDS Analysis

“…The printed circuit boards (PCBs) present in almost every single piece of electronic equipment, and account for roughly 5 wt% of the entire e-waste currently produced. Nevertheless, they carry the most important share of the valuable and also toxic metals [2,3]. This creates an urgent need for recovering/recycling valuable materials from PCBs.…”