METHOD BY WHICH IRON DUST CAN BE SEPERATED FROM COPPER DUST?
Very easy - use a magnet. However! You should place a sheet of plastic or paper between the dust and the magnet - if you get iron dust stuck on your magnet it's a pain in the a** to get it off!
How involved do you want to get? You could use water you could use gravity you could use magnetism- depends on you options and needs
