Making sodium nitrate

[NeighborJ]

I have an extremely limited knowledge of chemistry but I'm attempting a few experiments to try to expand my understanding. I have no reason to make NaNO3 opposed to buying it except to learn.

The equation I've selected is chosen from chemicals already in my collection.

Na2CO3(aq)+Ca(NO3)2(aq)--->CaCO3(s)+2NaNO3(aq) the CaNO3 has a mol wt of 164.088g/mol and I know the NaCO3 is 105.9888g/mol. I am planning on making the sodium carbonate from sodium bicarbonate by driving off the CO and H2O with heat. My first question- can I use the bicarb without driving off the CO and H2O? I do understand this will have a different mol weight.

Another question: Is there a table of solubility somewhere for these chems? And would there be any benefits to adding excess water to my aq solutions to ensure that temperature variations don't force some chems from solution?

[DavidF]

https://en.wikipedia.org/wiki/Solubility_table

 

This is my go to resource for solubility questions. It used to be that you could buy sodium carbonate as washing soda in grocery stores. Your calcium carbonate precipitate would be useful in pyro too. Win win for you.

[NeighborJ]

Thanks David I think I have enough info to get me in trouble. The CaCO3 is one thing I never acquired for pyro so it will be nice to have some home grown stuff. It appears that if my math is correct and I use the minimum amount of water to make my solutions then the resulting NaNO3 solution at 20C should need to be dehydrated by about 71% before It starts to precipitate.

[NeighborJ]

Ive got a few more questions, when i combined the two solutions it gave off an ammonia odor, is this normal or is it a sign of contaminants? Second question, How to dry the decanted NaNO3 solution? Can it be force dried or should i just keep it in my drying box until dried?

[Mumbles]

Ammonia is an odd smell for this reaction, though there are several potential sources. The first would be if you actually have calcium ammonium nitrate, or CAN. Ammonium carbonate can be decomposed into CO2 and ammonia. Alternatively, though less likely, is that there is something around that is reducing the nitrate. You have nitrate plus a pretty strong base. All one would need is a capable reductant. This is the same reaction that can happen between nitrates and certain metals used in pyro.

 

I wouldn't bother trying to make sodium carbonate. It's far too cheap to be worth the bother. If you just mix sodium bicarbonate and calcium nitrate together, it will basically do it for you anyway. Calcium bicarbonate is not a stable solid species. It can be formed to some degree, but is only stable in solution and generally requires CO2 to be added to the solution. It spontaneously dissociates into calcium carbonate, water, and CO2 when the water is removed or the CO2 is driven out of solution.

 

Drying is up to you. There will be a lot of water to be removed, which is an energy intensive process. I'd probably just let it evaporate naturally and dry the solid more thoroughly, but that's just me.

[DavidF]

NeighborJ didn't mention which sodium salt he used. Just pondering, I wonder if the sodium bicarbonate would have less contaminants than 'washing soda' because it is food grade. I have a question for Mumbles too. IF the sodium nitrate is to be used with magnalium, it seems to me that it would be better to end up with a slight excess of calcium nitrate than a slight excess of sodium carbonate, yes? Also, I wonder what simple method might be used to make sure this is the case. pH strips (non-bleeding) come to mind. My guess is that the calcium nitrate would be the main source of impurities if the sodium bicarbonate is used.

[NeighborJ]

David, I tested the sodium nitrate solution before I left for work this evening and found it to be quite hi(ph9). When I get home tomorrow morning I'll add some more CaNO3 to the solution to see if I can get the ph down below 7. The sodium bicarbonate I used was food grade and I cooked it down to soda ash.

[NeighborJ]

An update, I returned home and finished balancing the ph of my nitrate solution. It didn't take much extra CaNO3 to drop the ph to just under 7, no more than 5% of my original nitrate calculations. This doesn't make my original figures wrong because as DavidF pointed out it was likely water weight from its natural hygroscopic tendency. I've also come up with a theory for the ammonia odor at the beginning. The last time I used this mixing tub it was used for storing loose comp containing MgAl, and thou I washed it good, I believe some of the metals were still embedded in the pores of the plastic. This metal reaction would have also thrown off the amount of nitrates needed to complete the reaction.

I will allow the experiment to settle while I sleep and decant the clear solution in the morning.

[NeighborJ]

I have another chemistry question. The method I used to balance the ph just below 7 has undoubtedly left an unknown quantity of CaNO3 in my solution. I'm concerned that this will make an already hygroscopic chem even more so. If I were to complete the ph balance with KNO3 instead then I could mabe avoid ending up with any CaNO3 in my end product. Does KNO3 react with soda ash in the same manner? I can't seem to find an example in any balanced equation. I'd much rather have potassium as the contaminant than calcium.

Never mind about the KCO3 I found it on the solubility chart and it is quite soluble in water so it won't precipitate.

Edited January 5, 2017 by NeighborJ

[NeighborJ]

This little chemistry experiment has proven to be a lot of fun. I've made a batch of 600g NaNO3 and have another 5# batch in the drier. I think I will have enough to do everything I want for quite a while and will post some video of the stars once they are made.

[NeighborJ]

If anyone is curious the first batch of sodium nitrate was expected to yield 600g but thru filtering and the small amount which got left behind in the castings the yield was more like 552g. So it wasnt that wastefull and at a cost of only $1.26 per lb it is only slightly cheaper than i can buy it.

[Differential]

If you want to go one step further, try making your own nitrates with a "nitre bed" - basically a compost pile loaded with plenty of nitrogen. In the past, they would have used layers of manure and straw, and kept the pile damp, often with urine. The important thing is to give the nitrifying bacteria a warm, sheltered place to grow with plenty of air. Then you could mix in soda ash or wood ash, rinse and filter, and recover the nitrates. Takes about a year.

 

Probably not a great idea if you have a small yard or live in an apartment, though.

[NeighborJ]

Diff I'm not sure if I have the patience for the nitre bed but the thought has occurred to try to harvest it from the bat crap in some nearby limestone caves. I bet it would be a shitty experience but you never can be too prepared for the Zombie Apocalypse.

[WSM]

If you want to go one step further, try making your own nitrates with a "nitre bed" - basically a compost pile loaded with plenty of nitrogen. In the past, they would have used layers of manure and straw, and kept the pile damp, often with urine. The important thing is to give the nitrifying bacteria a warm, sheltered place to grow with plenty of air. Then you could mix in soda ash or wood ash, rinse and filter, and recover the nitrates. Takes about a year.

Probably not a great idea if you have a small yard or live in an apartment, though.

 

Eeeww!

 

Neighbors can be so intolerant at times.

 

WSM

 

PS - Which is why I never considered a nitre bed.

[NeighborJ]

Hehe, now that we've got the nitrates covered I think we can move on to sulfer. If only there was a volcano in western PA. Those zombies wouldn't stand a chance.

Back to reality, I assume the purpose of the wood ash filtering is to react the nitrates with the potassium hydroxide contained within? To make KNO3.

I am planning to try this with some of the NaNO3 I've made. I've never even researched about how to make lye. But it sounds more fun than digging up bat shut.

[Differential]

The nitrifying process tends to lower the pH, so adding ash helps to raise the pH (the bacteria like a mildly alkaline environment) and produce the KNO3. I'm using veggie waste from the kitchen and grass clippings, and there's no odor as long as the mix is light and fluffy. It's about half done, I'll see what kind of yield I get in the spring!

 

The upsides of living in Kansas is the land is cheap so I have a pretty big yard, and if there's any smell it'll be unnoticeable compared to the local feed lots.

[NeighborJ]

Diff,are you sure the nitre bed makes KNO3 or is it making NHNO3? The reason I ask is because I researched the possibility of converting the NaNO3 into KNO3 with KOH and it has no reaction, but it does work with the ammonium nitrate. So it would make more sense if the bed made the ammonia solution then was reacted thru the lye ashes and in the process raises the ph. The other possibility is the KNO3 made by the bed will likely have some NHNO3 contaminants and the lye reacts with those to create a purer product.

[OldMarine]

I watched a video of one of those prepper guys making his own nitrate for BP and after analysis he had mostly urea nitrate with most of the remainder being KNO3. It doesn't surprise me because he kept his bed wetted with urine.

Didn't sound like something I'd want to do here in the burbs.

[lloyd]

Patrick,

I always heard that any guy who 'wets the bed' after about age 12 has some real serious emotional problems!

 

Lloyd

[NeighborJ]

LOL, must be a burb thing.

[OldMarine]

I was referring to a nitre bed children!

[NeighborJ]

My 10# batch of sodium nitrate is finally dry. BUT there are issues. During the last two days of the drying process I noticed a sudden strong ammonia odor. I have suspicions that my CaNO3 had some ammonium nitrate contamination. So I decided to do a second recrystalization.

When I added the water to the tub, most of the nitrate quickly dissolved, however there was about 100g of clear crystals which never dissolved. The ph was also hi so I balanced it with a small amount of CaNO3. After filtering the solution I took those crystals and tried to dissolve them in fresh water with no luck.

I don't notice the ammonia odor at all in the second crystallization and it is drying way faster than the first time. Does anyone have ideas as to what these insoluble crystals are?

[MrB]

Hehe, now that we've got the nitrates covered I think we can move on to sulfer. If only there was a volcano in western PA.

 

Not exactly sure how, but i think your going to be stuck scavenging for sulfur. Car batteries comes to mind, but that is where the "how?" part comes in. The forklift has a leaking battery, which produces some obvious sulfur, so it IS possible, but purifying it, and making "lots" over short time... No idea.

 

Also, isn't there biological reactions that produce sulfur? Perhaps that could be exploited.

 

Guess we are getting of topic. Sorry.

B!

[Differential]

Diff,are you sure the nitre bed makes KNO3 or is it making NHNO3? The reason I ask is because I researched the possibility of converting the NaNO3 into KNO3 with KOH and it has no reaction, but it does work with the ammonium nitrate. So it would make more sense if the bed made the ammonia solution then was reacted thru the lye ashes and in the process raises the ph. The other possibility is the KNO3 made by the bed will likely have some NHNO3 contaminants and the lye reacts with those to create a purer product.

I think the products from the nitre bed include calcium nitrate, so adding potassium carbonate in the form of wood ashes helps precipitate the calcium. And if you had ammonium nitrate (NH4NO3), adding alkali would help off-gas the ammonia.

[Differential]

^{Not sure why you'd want to try making sulfur out of sulfuric acid. Most people would want the reaction to go the other way!}

^{I've seen a thin layer of sulfur in the top of an anaerobic sewage digester once, but most people don't have (or want!) millions of gallons of sewage. Sulfur makes up a pretty small percentage of biomass, and the pathway to elemental sulfur usually involves highly toxic H2S.}

^{But yes, you could make sulfur particles by passing the horrible fumes from decomposing matter through ozonated water.}

^{If I HAD to make sulfur, I would probably start with iron pyrite.}

Edited January 20, 2017 by Differential