# Energy cost during neodymium magnet production?

Pretty straight forward. Whats the amount of energy needed to create a neodymium magnet? What's the cost ratio? These magnets are expensive, but is the amount of energy needed to create them very high (2Kw)? Or is it still pretty reasonable? Does anyone have a link with accurate estimations?

Simon Bridge
Homework Helper
Welcome to PF.
People asking questions like that are usually thinking of a magnet as having some sort of energy store that can get used up over time in various clever devices. Is that what you are thinking of?

Anyway - neodynium magnets are expensive because they are made out of a rare earth. It's rare. If you made a magnet out of diamonds you'd expect it to be expensive too right?

To make these magnets, you don't start out with a block of Nd2Fe14B and then magnetize it - what you do is get a whole load of grains of the stuff, align them, and then smelt them into a block. Or something like that. Rotating all those little grains can't be all that hard ... but I imagine the actual field strengths used in production will be protected information.

The furnace will be the largest energy cost.
http://en.wikipedia.org/wiki/Neodymium_magnet#Production

Don't know what you mean by "cost ratio" ... ratio of what?

Hi Simon,

Actually, the reason I am asking is because I know that magnets can, over time, lose their magnetic properties. I am building a device which will utilize magnets for energy generation. I'm curious what the energy expenditure is for neodymium magnets in production to calculate whether the device is more energy efficient than other energy creation methods.

For instance, coal provides a net positive energy source because the mining operations used to acquire coal take a fraction of the energy the coal itself can provide. On the flip side, oxyhydrogen generation is a net negative energy source because the energy required for electrolysis exceeds the energy ultimately released by oxyhydrogen (HHO) combustion.

Simon Bridge
Homework Helper
I am building a device which will utilize magnets for energy generation.
That's what I figured.

You can pretty much figure the energy cost is factored into the price - recalling that actual production details are likely to be classed as trade secrets, you are unlikely to be able to know how much energy goes into a particular brand of magnet. What you really need to know is how long they last.

Generally the energy cost to make a magnet, even these exotic ones, would be in the small side of your examples. Particularly compared with their strength - it's part of what makes them so attractive.

To compare yours with other generators, you really just need the efficiency.