vudiemphuongchi - 20-4-2019 at 17:56
Hello everyone. I want to make a question that is intriguing me for a while.
So. I bought a pack of saltpeter but it has two components in it: sodium nitrate and potassium nitrate. I suspect that might be a 50:50 mixture or
65:35 based on some data sheets i found in the internet. But I'm not really sure. Ok, so this is the thing, i'm only interested in the potassium
nitrate and i want to convert the remaining sodium nitrate in the mix to KNO3 too, but i'm not sure if my plan is gonna work so i want your opinion.
So, i plan to dissolve all the nitrate in hot water and mix potassium chloride and try to precipitate the KNO3 out by cooling the solution in the
freezer and then filtrating out the KNO3 crystals. But I'm not sure if that is gonna work since i heard that this double displacement reaction can't
occur according to some forums. But I'm not 100% convinced of it.
So, what you guys sugest? I'm not a chemistry expert and don't have access to all chemicals i might need. So i want some suggestion for something i
can do at home with no fancy glassware or inaccessible chemicals.
I know i can buy pure KNO3 but i'm not willing to and i'm interested in using this that i already have. But anyways. Thank for any answers and your
time.
clearly_not_atara - 20-4-2019 at 20:58
The solubility of potassium chloride is not very high. I suggest using a more soluble potassium salt such as K2CO3, or, since that might precipitate
some Na2CO3, KOAc.
Bedlasky - 20-4-2019 at 21:08
Hi.
In my opinion it should work. Solubility (at 0°C) of KNO3 is 133 g/l, NaNO3 730 g/l and KCl 280 g/l. Solubilities will be different of cource because
NaNO3 will decrease solubility of KNO3 (and conversly). If you added some KCl to saturated solution of your KNO3/NaNO3, some KNO3 will be precipitate.
After filtration you can use fractional crystalization and separate some KNO3 from solution.
[Edited on 21-4-2019 by Bedlasky]