Classification of Non-ferrous Metals using Magnetic Induction Spectroscopy
Journal: IEEE Transactions on Industrial Informatics
Publication Date: 25 December, 2017
Department of: Electrical and Electronic Engineering
A new sensor to help recycle valuable non-ferrous metals such as copper, aluminium and brass.
Global demand and resource volatility has intensified the need for a circular economy, where waste becomes feedstock for the new.
Vehicles, electronics and other consumer products often contain large quantities of recyclable non-ferrous metals such as copper and aluminium. As these metals are non-magnetic however, they can be difficult to separate and sort. Often, this fraction is exported to low-wage economies to be separated by hand; a laborious process which leaves vast quantities of small fragments for landfill. A better solution is needed.
Researchers at the University of Manchester have discovered a new method to identify non-ferrous metals using multi-frequency induction. Their solution uses knowledge of how eddy currents circulate in metal fragments – specifically how currents tend towards the fragment’s surface as frequency increases – to determine the electrical conductivity of metal pieces, irrespective of the differences in size and shapes of the pieces which usually convolutes measurement.
They have created a new multi-frequency induction sensor using this method to sort non-ferrous metals moving on a high speed conveyor belt. The sensor achieved 92% recovery and purity rates in laboratory trials.
The technology is attracting the focus of industry, and is a candidate for commercialisation – creating a new, cost-effective metal classification solution born of original university research.