Separating KNO3 and NH4NO3

[Rhadon]

I hope to find someone who can help me with the following problem: I want to separate an equal mixture of potassium nitrate and ammonium nitrate - one method would be converting the ammonium nitrate to potassium nitrate by adding KOH, another one would be separating the substances making use of the different solubilities in water. But that's not really what I want. The best solution for me would be separating them without decomposition of any compound.

Thanks in advace
Rhadon

[kingspaz]

why not use the difference of solubilities?...dissolve in the smallest amount of boiling water possible. allow to cool, filter out KNO3. evaporate remaining liquid from which the KNO3 was filtered from. this will leave you AN in your frying pan!!

[Rhadon]

Yes, I know, at first this seems to be a good method, but actually it isn't.
When preparing a hot saturated solution of NH4NO3 and KNO3 and cooling it down the less soluble KNO3 falls out you get some KNO3. But there will always stay a relatively high amount of potassium nitrate in the ammonium nitrate solution.
Separating the two compounds completely is very hard, I know, and it's even harder to find a procedure to do it economically.

[kingspaz]

what about convert the AN to KNO3 with KOH then collect all the KNO3 then convert some of the KNO3 back to AN with ammonium chloride or somthing. its alot of work but and not very economical but i can't think of anything else that could be done.

[Rhadon]

Nice idea, but are you sure KNO3 can be converted to NH4NO3 with NH4Cl?