Sciencemadness Discussion Board

How to separate iron oxalate and manganese oxalate

veerendra - 7-2-2014 at 20:04

I have iron oxalate and manganese oxalate in solution of oxalic acid. is there any way to separate Mn Oxalate and Fe Oxalate ?

organichem - 8-2-2014 at 01:35

Fe ions are only soluble in acidic oxalate solutions. Mn ions seem to act in a similar way,
so you could try to adjust the pH value by adding dilute NaOH until precipitation
occurs.
To get the exact pH range you can use a Mn oxalate and a Fe oxalate solution seperately, add NaOH until precipitation and measure pH. If the values are too close
you could try adding a buffer system for this range to faciliate separation (I don't know how precise your ability of pH measurement is).
I once did a separation of ions in oxalatic solution this way, but had to reprecipitate twice to get the iron content under 10 ppm (I as well don't know which purity is desired by you)

veerendra - 9-2-2014 at 19:55

Dear Sir

In this case it will precipitate in the form of Fe-Hydroxides. I want it in the form of oxalate.

Thanks

turd - 10-2-2014 at 04:04

This ain't organic chemistry.

macckone - 10-2-2014 at 08:31

Quote: Originally posted by veerendra  
Dear Sir

In this case it will precipitate in the form of Fe-Hydroxides. I want it in the form of oxalate.

Thanks

Separate the oxalic acid.
Then combine it with pure iron oxide.
manganese and iron oxalate are probably going
to be too similar to separate cleanly.

Choices are fractional crystallization is going to be
very hard due to the low solubility.
But manganese oxalate is 20% more soluble so theoretically
it could be done.

Possibly using a soxhlet extractor where
the manganese oxalate will dissolve more readily than the
ferric oxalate.

blogfast25 - 10-2-2014 at 14:07

Separating Fe and Mn as oxalates is unlikely to work well. Convert the oxalates back to hydroxides and separate these. Then convert back to oxalates.