Sciencemadness Discussion Board

Separation of Sodium Acetate and Sodium Nitrate

Dollfin - 13-10-2015 at 07:50

So, I made a big mistake. I was working on my homemade venison jerky, and through a careless sweep of my arm, knocked a bucket of sodium acetate into a bucket of sodium nitrate. Gah.

The recipes I follow require specific measurements of each one, and I know they're both white, crystalline, and water-soluble sodium salts. It's not the end of the world, but if it's possible, I'd really like to separate the two instead of buying new supplies (this error ruined hundreds of dollars worth of the sodium salts, if they're inseparable.) Plus they're roughly the same crystal size, so I can't just sieve out one from the other.

Am I screwed? Is there any way to separate the two? I'll appreciate any answers, cost-effective or not, at least so I know what to do if I make the mistake again. First preventative measure is keeping both buckets on the floor instead of putting one on the shelf. :D

Thanks in advance!

Detonationology - 13-10-2015 at 07:56

Ah shit... Assuming it was only a a few pounds, you're best off by just throwing it out; they are both cheap chemicals.

EDIT:Just now realized you said "hundreds of dollars" worth...

[Edited on 10-13-2015 by Detonationology]

Praxichys - 13-10-2015 at 08:07

That's pretty bad. Separating them and allowing them to remain food-grade is definitely not economical.

If you can determine the original amount of one of the chemicals, you can determine how much of one is in the other. You could then adjust the concentration by adding more of one or the other to get it to the correct mixture used in your recipe.

Dollfin - 13-10-2015 at 08:19

Ooh! I didn't think about that. I was planning to just scoop out the top layer of acetate and run taste tests to see where the nitrate salts begin, but that'd take a lot of taste tests and be pretty imprecise. Since I only run one recipe (for several friends/buyers), and I know how much of each material is in each bucket (thanks, precision scale!), I'll just add in what I need to in order to balance the requirements and mix it evenly, or just make an obscenely large batch of marinade and store it.

It's a shame that the salts can't be easily separated. But, hey, it's a learning experience. Namely, don't put a large, open container of Chemical A directly above a large, open container of Chemical B. Just glad it wasn't an explosive combination.

Thanks, Praxichys!

Upsilon - 13-10-2015 at 09:42

If push comes to shove and you can't find a good way, you can at least convert it all to sodium acetate. Provided you have a suitable heat source, sodium nitrate will decompose into sodium oxide and nitrogen dioxide at around 380C while the sodium acetate will remain stable. After it cools, add an excess of regular vinegar - this will convert the sodium oxide to sodium acetate.

Artemus Gordon - 13-10-2015 at 14:04

This is a purely theoretical idea, but Wiki says Sodium acetate trihydrate "melts" at 58 degC (actually it dissolves into its own water of hydration). I assume Dollfin's Sodium acetate is in fact the trihydrate. Since these are both Sodium salts, the common ion effect should keep most of the Sodium nitrate undissolved, and then you could filter it. You would still probably have some mixing of the two, so Praxichys idea is still the most practical.

Tdep - 13-10-2015 at 15:45

Woah Artemus, I see you haven't tried to filter a molten compound before haha, that could possibly be the messiest idea I've heard in a while. But, pointing out the difference in melting points is very good. Checking the melting point (and it should be super easy to tell given the vast difference) is a much better way to check if you've physically separated the solids rather than a taste test.

Heating the whole mix probably won't seperate the solids and liquid due to density differences but that's still an idea if you're really keen, probably about as messy as hot filtering molten solids

Artemus Gordon - 14-10-2015 at 16:57

True, I have not tried this, but the acetate isn't really molten. You may be right that the acetate stays too viscous to flow through a filter. I do know that dry heated epsom salts becomes quite liquid, but that is a heptahydrate, not a trihydrate.

Oscilllator - 14-10-2015 at 19:09

I've heated Sodium acetate trihydrate before, and it dissolved into a water-like liquid, so the only problem with filtering it would be doing it before the acetate re-solidified.
A heated buchner funnel with vacuum filtration would probably do the job just fine, but somehow I doubt that Dollfin has one. With gravity filtration it may be possible through the use of a heat gun on high and some patience, but I imagine all that would achieve is an even messier situation.

I think the best way to resolve this situation would be to what Praxichys says and add the right amount of one chemical such that the right mixture is achieved. This requires no equipment, and will not result in the loss of any of the chemicals.