Eddy Current Separator
An Eddy Current Separator (ECS) is a machine that is used to separate and recover non-ferrous metals such as aluminium, copper and brass from non-metallic material in a waste stream[1]. Material is fed onto the conveyor of the separator, which moves it across the magnetic rotor, situated underneath, to cause in separation. The two resultant streams discharge into different bins/compartments with the aid of the splitter which divides the non-ferrous metal from the non-metallic waste such as paper, plastic, wood or auto shredder residue (known as shedder fluff)[2]. This process is usually employed after magnetic separation has removed the bulk ferrous fraction from a scrap material stream[3].
The Magnet Rotor
The key component is the magnetic rotor, which is a series of permanent rare earth magnets mounted on a support plate attached to a shaft. The magnetic rotor is surrounded by, but not attached to, a non-metallic shell which supports the conveyor belt. This allows the rotor to spin independently and at a much higher speed than the non-metallic shell and belt[2].
Benefits
- Very high hit rates
- Very high purity rates
- Compact and flexible
- Removes ranging sizes of non-ferrous materials[1]
The Process
- The waste stream is fed onto the conveyor belt and is transported towards the magnetic rotor end.
- When a piece of non-ferrous metal passes over the magnetic rotor, the magnets inside the shell rotate past the metal at high speed which forms eddy currents to create a magnetic field around the piece of metal.
- The polarity of that magnetic field is the same as the rotating magnet, causing the non-ferrous metal to be repelled away from the magnet.
- This repulsion makes the trajectory of the non-ferrous metal greater than that of the non-metallic, allowing the two material streams to be separated[2].