Eddy current separation for recovery of non-ferrous metallic particles: A comprehensive review

Abstract Eddy current separation (ECS) is a process used throughout the scrap recycling industry for sorting nonferrous metals from other nonmetallic fluff. The mechanism is based on the principle that a time-varying magnetic field will induce electrical current to flow throughout the body of a conductive particle. This current then reacts to the applied magnetic field by exhibiting a pronounced force of deflection, thereby separating the materials. The process is remarkably efficient and environmentally friendly, making it essential to the growth and sustainability of the metal recycling industry. In this review, we aim to summarize the available literature on eddy current separators for recovery of nonferrous metals. Although several different designs of eddy current separators have been examined through the years, the most common in use today remains the belt-driven rotary drum design. Limitations of the belt-driven rotary drum design are discussed as well as potential new designs and new applications for eddy current separators.

[1]  G. Lohoefer.  Theory of an electromagnetically levitated metal sphere. I - Absorbed power , 1989 .

[2]  D. Fletcher,et al.  Eddy-current separation of non-ferrous conductors and non-conductors: theory and initial experiments , 1991 .

[3]  Patrik Söderholm,et al.  Resolving failures in recycling markets: the role of technological innovation , 2012 .

[4]  P. C. Rem,et al.  Simulation of eddy-current separators , 1998 .

[5]  Z. Schlett,et al.  Eddy-current separator with inclined magnetic disc , 2002 .

[6]  R. Ludwig,et al.  A quantitative analysis of the separation of aluminum cans out of a waste stream based on eddy current induced levitation , 1997 .

[7]  Rolf Widmer,et al.  Scarce metals in conventional passenger vehicles and end-of-life vehicle shredder output. , 2015, Environmental science & technology.

[8]  James R. Nagel,et al.  Induced Eddy Currents in Simple Conductive Geometries: Mathematical Formalism Describes the Excitation of Electrical Eddy Currents in a Time-Varying Magnetic Field , 2018, IEEE Antennas and Propagation Magazine.

[9]  P. Crowson.  Some observations on copper yields and ore grades , 2012 .

[10]  Peter Carlo Rem,et al.  A model for eddy current separation , 1997 .

[11]  Eric Forssberg,et al.  THE CURRENT STATUS OF EDDY CURRENT SEPARATION , 1998 .

[12]  Jie Zheng,et al.  Key factors of eddy current separation for recovering aluminum from crushed e-waste. , 2017, Waste management.

[13]  D. Cohrs,et al.  Forces on Particles in Time-Varying Magnetic Fields , 2018 .

[14]  Eric Forssberg,et al.  Mechanical recycling of waste electric and electronic equipment: a review. , 2003, Journal of hazardous materials.

[15]  J. Oberteuffer,et al.  Magnetic separation: A review of principles, devices, and applications , 1974 .

[16]  R. Qiu,et al.  Environment-Friendly Technology of Recovering Full Resources of Waste Capacitors , 2017 .

[17]  Mihai Lungu,et al.  Vertical drum eddy-current separator with permanent magnets , 2001 .

[18]  Mihai Lungu.  Separation of small nonferrous particles using an angular rotary drum eddy-current separator with permanent magnets , 2005 .

[19]  S. Kawatra,et al.  Coal Desulfurization: High Efficiency Preparation Methods , 2001 .

[20]  C Caizer,et al.  A new wet Eddy-current separator , 2002 .

[21]  Eric Forssberg,et al.  Aluminum recovery from electronic scrap by High-Force® eddy-current separators , 1998 .

[22]  Fabrizio Passarini,et al.  Automotive shredder residue (ASR) characterization for a valuable management. , 2010, Waste management.

[23]  S. A. Kercher,et al.  Scrap processing by eddy current separation techniques , 1982 .

[24]  Eric Forssberg,et al.  Particle trajectory simulation of two-drum eddy current separators , 1999 .

[25]  Tilmatine Amar,et al.  Design and development of a low cost technique for sorting household wastes using eddy current separation process , 2016 .

[26]  H. J. Trodahl.  Far-infrared absorption by eddy currents in ultrafine metal particles , 1982 .

[27]  Nawshad Haque,et al.  Energy and greenhouse gas impacts of mining and mineral processing operations , 2010 .

[28]  Zhenming Xu,et al.  Constructing environment-friendly return road of metals from e-waste: Combination of physical separation technologies , 2016 .

[29]  Qian Yiming,et al.  Environment-friendly technology for recovering nonferrous metals from e-waste: Eddy current separation , 2014 .

[30]  Z. Schlett,et al.  A new static separator for metallic particles from metal–plastic mixtures, using eddy currents , 2002 .

[31]  Ernst Schlömann.  Separation of nonmagnetic metals from solid waste by permanent magnets. I. Theory , 1975 .

[32]  Jirang Cui,et al.  Recycling of automotive aluminum , 2010 .

[33]  Peter Carlo Rem,et al.  Modelling the throw of metals and nonmetals in eddy current separations , 2004 .

[34]  Zhenming Xu,et al.  Approaches to improve separation efficiency of eddy current separation for recovering aluminum from waste toner cartridges. , 2012, Environmental science & technology.

[35]  Zhenming Xu,et al.  Eddy current separation technology for recycling printed circuit boards from crushed cell phones , 2017 .

[36]  D. Cohrs,et al.  Eddy Current Separation of Nonferrous Metals Using a Variable-Frequency Electromagnet , 2017 .

[37]  R. Cossu,et al.  Automotive shredder residue (ASR) management: An overview. , 2015, Waste management.

[38]  Reid Lifset,et al.  Dining at the periodic table: metals concentrations as they relate to recycling. , 2007, Environmental science & technology.

[39]  D. Koca,et al.  An assessment of metal supply sustainability as an input to policy: security of supply extraction rates, stocks-in-use, recycling, and risk of scarcity , 2017 .

[40]  Z. Schlett,et al.  A new possibility in Eddy-Current separation , 2002 .

[42]  Y. R. Smith,et al.  Electrodynamic Eddy Current Separation of End-of-Life PV Materials , 2017 .

[43]  Eric Forssberg,et al.  Separation mechanisms and criteria of a rotating eddy-current separator operation , 1999 .

[44]  Sharif Jahanshahi,et al.  Low grade ores – Smelt, leach or concentrate? , 2010 .

[45]  Zhenming Xu,et al.  Hollow Aluminum Particle in Eddy Current Separation of Recovering Waste Toner Cartridges , 2017 .

[46]  Zhenming Xu,et al.  A new model of repulsive force in eddy current separation for recovering waste toner cartridges. , 2011, Journal of hazardous materials.

[47]  Peter Carlo Rem,et al.  Eddy Current Separation of Fine Non-Ferrous Particles from Bulk Streams , 2004 .

[48]  Y. Mitoma,et al.  Sustainable recovery of precious metals from end-of-life vehicles shredder residue by a novel hybrid ball-milling and nanoparticles enabled froth flotation process , 2018 .

[49]  P. Rony.  THE ELECTROMAGNETIC LEVITATION OF METALS , 1964 .

[50]  P. Rem,et al.  Separation of small nonferrous particles using an inclined drum eddy-current separator with permanent magnets , 2002 .

[51]  D. A. Dunnett.  Classical Electrodynamics , 2020, Nature.

[52]  J. Nagel.  An analytic model for eddy current separation , 2018, Minerals Engineering.

[53]  Yanjun Hu,et al.  Recovery of Aluminum Residue from Incineration ofCans in Municipal Solid Waste , 2015 .

[54]  E. Forssberg,et al.  The Investigation of Separability of Particles Smaller Than 5 mm by Eddy Current Separation Technology. Part I: Rotating Type Eddy Current Separators , 1999 .