Development of a Physical Separation Route for the Concentration of Base Metals from Old Wasted Printed Circuit Boards

Pedro Jorge Walburga Keglevich De Buzin,Carlos Hoffmann Sampaio,Rejane Maria Candiota Tubino,Weslei Monteiro Ambrós,Irineu Antônio Schadach De Brum,Josep Oliva Moncunill

doi:10.3390/min11091014

Pedro Jorge Walburga Keglevich De Buzin, Carlos Hoffmann Sampaio + Show 4 more

Open Access

https://doi.org/10.3390/min11091014

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Abstract

Wastes from old electronic devices represent a significant part of the electronic scrap generated in developing countries, being commonly sold by collectors as low-value material to recycling hubs abroad. Upgrading the quality of this waste type could drive the revenue of recyclers, and thus, boost the recycling market. On this basis, this study investigated the possibility of concentrating metals from old wasted printed circuit boards through a physical separation-based route. Preparation of samples comprised fragmentation, size classification, density, and magnetic separation steps, followed by chemical and macro composition analysis. Cu, Al, Fe, and Sn constituted the major metals encountered in the scraps, including some peak concentrations of Zn, Sb, Pb, Ba, and Mn. Four distinct concentrate products could be obtained after suitable processing: (a) a light fraction composed of plastics and resins; (b) an aluminum concentrate; (c) a magnetic material concentrate, containing mainly iron; (d) a final concentrate containing more than 50% in mass of copper and enriched with nonferrous metals. Preliminary evidence showed that further processes, like the separation of copper wires through drumming, can potentially improve the effectiveness of the proposed processing circuit and should guide future works.

Highlights

The growing global demand for metals stands in contrast to the current scenario of decreasing ore grades, more complex mineralogy, and more intense environmental concerns related to the extractive sector
Development and improvement of physical separation operations for wastes from electrical and electronic equipment (WEEE) recycling, Within the context above, and as part of an ongoing project concerned with the this paper aims to examine the feasibility of recovering metals and generating metal development and improvement of physical separation operations for WEEE recycling, concentrates through the application of physical separation techniques in wasted printed this paper aims to examine the feasibility of recovering metals and generating metal circuit boards assemblies (PCBAs)
Electronic wastes from old devices, such as TV boards and stereos, generally have fewer valuable metals when compared to new ones, so that its recycling has been little addressed in the literature

Summary

Introduction

The growing global demand for metals stands in contrast to the current scenario of decreasing ore grades, more complex mineralogy, and more intense environmental concerns related to the extractive sector. Expected advances in sustainable energy technologies and the boom of automation leveraged by the industry 4.0 transition should increase even more both the demand for metals and the generation of their respective waste products. In this context, the term “urban mining” [1]. Has emerged as a concept that goes beyond recycling as a mere ecological activity, but rather as a necessity aimed at maximizing the use of non-renewable resources such as metals through technologies that minimize environmental impacts Because they include non-ferrous and precious metals such as gold, copper, cobalt, and rare earths in their composition, wastes from electrical and electronic equipment (WEEE) are among the main targets of urban mining. For instance, recycles only about 4% of its total solid waste generated [4]

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