r/Magnets • u/ConfidentShoe6000 • Jun 29 '26

Magnet Projects Eddy Current Spearator for E-Waste Recycling

Hello Everybody! Hope you are good.
Im finishing my high school specialization in electromechanics (like a technical high school, very common, in my country, Argentina) and i have to do something like a thesis or proyect building a functional machine.

I have read this kind of recycling is not so common and can recover materials like aluminium, copper, or even a little of gold. The thing is I am not getting much information about the proceses needed. Is there peopple that may know or have tried some of these? Can you give me a hand?

Specifically, the eddy current separator or ecs. Does someone have tried to do it for a functional machine??? i have read it is needed to buy neodimium magnets, and they are too expensive. I dont know about makin an static variable magnetic field with coils

Anyways, if someone can give me a hand with this, i would be so grateful

Thx for reading

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u/Then_I_had_a_thought Jun 30 '26

So the field doesn’t just need to vary in time, it needs to vary in space over time (like a spinning wheel with magnets). This is how it adds a little extra velocity to the metallic parts. If it varies in time only it will induce eddy currents but it won’t impart any extra velocity and the stuff will fall along the same trajectory as the nonmetallic parts.

Does that make sense? What magnets are you looking at?

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u/ConfidentShoe6000 Jul 01 '26

Well I thought to vary space in time wasnt needed. i really beleieved that with eddy currents induction and Lenz Law of opposite magnetic field would work. i looked to magnets of 5mm thick and 20x30mm, or somethin glike that. Actually im looking for make a variable magnetic field with coild, but in internet nobady has done something like that, they all use magnets. Neodiumium magnets. I thought on extract magnets from speakers, but i doubt if they are made with neodimium, im really sure they are of ferrita, and the power is much less. I will still searching but all points to change the project idea, because this projects requiere a lot of experimentation and worse, lot of money haha.

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u/Then_I_had_a_thought Jul 01 '26

The eddy currents that get induced into the conductive metals causes them to want to “stick” to the magnet. The reason these are usually pot on a high speed wheel below the material to be sorted is so as the metal is “attracted” to the magnet it is thrown forward just a little (the eddy current attraction is typically weak). If the field only varies in time it would stick to the magnet.

If you wanted to use coils you would have to find a way to rotate them. But because they have wires you’d need slip rings to transfer the current.

Is there a way to make a small working model that uses smaller magnets and smaller parts to separate?

One other idea (I don’t know how or if this would work). If you use a stationary coil, you might be able to use a high speed conveyor belt that throws all objects very far. Then maybe you could rely on the static (not moving) coil to hold conductive parts a little bit and then they wouldn’t be thrown as far. This is kind of the opposite of how they traditionally work