Foeskes - 2-10-2018 at 16:04
So I tried to extract neodymium out of some old neodymium magnets, I tried dissolving it in dilute H2SO4 first but switched to HCl and I mixed the two
and added oxalic acid hydrogen peroxide and potassium hydroxide, this makes the solution bright green and formed a precipitate. I filtered and washed
the precipitate and it has a light tan color in fluorescent lighting and pretty much the same color in sunlight. It's still damp but I don't think it
would change the color by much. What could this be?
The magnets are definitely neodymium iron boron magnets, judging from the color of the acid solution(green) it shouldn't have any Cobalt.
fusso - 3-10-2018 at 03:17
Did you put enough oxalic acid to keep Fe3+ in solution?
Foeskes - 3-10-2018 at 07:06
I added a excess of oxalic acid. I washed it with 35% HCl and water and now it's white, let's see how it will look.
It the contaminant seems to be resistant to oxalic acid and potassium oxalate washes.
Jackson - 3-10-2018 at 08:21
I know that neodymium magnets can have other rare earth metal contaiminates. Maybe that is changing the color?