Printed Circuit Boards Recycling: Characterization of Granulometric Fractions from Shredding Process

Paula C. Oliveira; Marta Cabral; Carlos A. Nogueira; Fernanda Margarido

doi:10.4028/www.scientific.net/MSF.636-637.1434

Paper Titles

Synthesis and Characterization of Biodiesel from Coconut Oil Using Homogeneous Catalyst
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Waste Fibre Reinforced Ecocomposites
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On the Thermal Characterization of Fibers Prepared by Cryogenic Grinding of Scrap Tires
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Characterisation of Cutting Systems on Physical Processing of Spent Batteries
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Printed Circuit Boards Recycling: Characterization of Granulometric Fractions from Shredding Process
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Demonstration of the Robustness of Maximum Likelihood Estimation to Distinguish Mixtures of Two Weibull Populations in Failure Data of Brittle Materials
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Repair Welding Effects on the Bending Fatigue Strength of AISI 4130 Aeronautical Steel Used in a Critical to the Flight-Safety Structure
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Relation between the Mechanical Behaviour of a High Strength Steel and the Microstructure in Gigacycle Fatigue
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Evaluation of the Relationship between Diamond Tool Wear Performance and the Mechanical Properties of the Individual Metallic Binders
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HomeMaterials Science ForumMaterials Science Forum Vols. 636-637Printed Circuit Boards Recycling: Characterization...

Printed Circuit Boards Recycling: Characterization of Granulometric Fractions from Shredding Process

Abstract:

In electronic appliances, printed circuit boards (PCB) represent an important component, containing high grade of valuable metals, besides organic resins and some ceramic materials. Copper is the major metal in PBC’s composition (normally higher than 20% w/w) but many other secondary and minor metal elements, including precious metals, are found in PCB’s. Recycling of PCB´s involves firstly the shredding operation, which is crucial in order to liberate particles from different materials, allowing its further processing by other mechanical, physical and chemical technologies. An efficient shredding operation is difficult to achieve due to the high heterogeneity of these wastes involving materials with different mechanical properties and complex assemblies. This paper presents results from laboratorial studies of shredding of PCB’s and the evaluation of size reduction efficiency as well as the chemical characterization of the obtained shredded fractions. Results showed that an efficient size reduction (characteristic average diameter d50=1.0mm) is obtained using two shredding stages of PCB’s, the first one with a grab shredder and the second one with a cutting mill. Chemical analysis of shredded PCB’s indicated that copper is the principal metal present (28%) followed by Sn, Zn, Pb and Al (3-5%) and many other minor elements. The fine fractions were rich in plastic materials while the metals were essentially present in the intermediate fractions (0.3-1.5 mm). These results can lead to guidelines regarding further design of the physical separation steps in the recycling processes.