Strontium nitrate from strontium carbonate

[THEONE]

I just got some Sr carbonate and tried to make some Sr nitrate with ammonium nitrate. I measured out 400g of Sr(NO3)2 and 450g of AN. AN dissolved and heated up, then SrCO3 was added. The weird thing is that i could not smell any ammonia so no reaction took place, and after i dried the mixture, i added some HNO3 and bubbling occurred so it is still mostly Sr carbonate. Any idea why the reaction did not work?

Edited February 10, 2020 by THEONE

[zZz]

Up

[PTFE]

why not use the hno3 directly?

[THEONE]

To save that HNO3

[RichardH08]

That method only works well with soluble carbonates. The problem is that SrCO3 is almost completely insoluble in water (about 0.65 g per litre at 100 °C, and much less at lower temperatures) so the reaction, if it happens at all, will be VERY slow.

In practical terms, that isn't a feasible way to make Sr(NO3)2.

[Richtee]

I used to just water extract road flares. Worked pretty well as I recall. Just soak for a day, strain and evap. Not pure, but works well.

[SharkWhisperer]

Is this for sport or educational exercise, or is strontium nitrate, like other oxidizers such as perchlorates and chlorates, of limited/restricted availability in many places?

 

Here in the US, strontium nitrate is pretty inexpensive and easily available; I use a lot. Strontium carbonate is also easy to find, but my use is restricted to low quantities for various colored star formulations, so a little goes a long way.

 

I have nothing but respect for fellow pyros that by necessity (or just curiosity) manufacture their own reagents; I used to for sport and education, but now it's just so much easier to have it shipped to your front door...

[WSM]

To save that HNO3

 

So it boils down to which one you want more, HNO₃ or Sr(NO₃)₂ ?

 

WSM

Edited February 16, 2020 by WSM

[markx]

Sr carbonate works pretty good for red flame formulations on it's own....so there is really no immediate need to convert it to the nitrate salt. The contrary could be stated about barium carbonate which does not really want to produce a rich saturated green. A mediocre green is achievable though.

On a general note of converting a metal carbonate into said metal nitrate via a metathesis reaction through ammonium nitrate, it always requires an elevated temperature and a lengthy reaction time. Meaning you have to boil the combined solutions/carbonate residues to promote the breakdown of ammonium carbonate into free ammonia and carbon dioxide. Just adding AN solution to the carbonate does not work and at room temperature the balance is shifted towards the formation of the insoluble metal carbonate and AN.....your starting materials. But raising the temperature shall shift the balance towards the breakdown of ammonium carbonate, which leaves the solution and abandons the metal from the carbonate combined with the nitrate in the remaining solution.

I performed a bulky synthesis of barium nitrate this way starting from solid barium carbonate and AN solution. It took about 12 hours of simmering on a hot plate under fume hood before the emission of ammonia died down and I could filter the solution to further boil it down into solid barium nitrate residue.

[THEONE]

I did the whole reaction at above 150 C. The problem is the low solubility of Sr carbonate. Also BaCO3 got pretty low solubility. How exactly was your procedure, maybe the carbonate 1st must be added and then the AN. I did the opposite way, not sure if this is the reason why it did not worked out.

Edited February 10, 2020 by THEONE

[markx]

I did the whole reaction at above 150 C. The problem is the low solubility of Sr carbonate. Also BaCO3 got pretty low solubility. How exactly was your procedure, maybe the carbonate 1st must be added and then the AN. I did the opposite way, not sure if this is the reason why it did not worked out.

Are you sure the stuff you got was strontium carbonate? Perhaps it was sulfate or some other strontium salt of an acid that forms a stable ammonium salt.....

Maybe the carbonate was not fine enough for the process to work, but concidering that you went up to 150C with no ammonia evolution suggests the problem is not in the fineness of the initial carbonate fraction. Are you sure about the composition of your AN? If you used fertilizer grade then be aware that nowadays the pure stuff is rare and basically unobtainable for simple people...it is all a mix with sulfates and other inert additives to render it undetonable in agricultural application. There might lie another reason for the failed process...

 

My approach with the barium variety of this reaction was simple: to a big stainless steel pot containing a liberate amount of water, a stoichiometric amount of barium carbonate + AN were added in no particular order or preparation manner and the soup was brought to a slight boil. The carbonate was of pottery/technical variety, so not a very pure starting material, but it worked just fine. I did not control the temperature or concentrations closely ( in fact not at all, just the ratio of AN to BaCO3 was chosen to resemble stoichiometric values with a slight excess of the carbonate to force all of the ammonia out of solution). That stew was cooked on a slight boil for about 12h with frequent additions of water to replenish the evaporation losses. In fact it might have been longer than 12h, I do not remember the details any more as the procedure was performed more than a decade ago I remember that at after a certain time of boiling I could see a percipitate of barium nitrate forming in the pot. Different looking crystals appeared in the midst of the carbonate mass. After the ammonia evolution stopped, the stew was diluted so as to dissolve all of the barium nitrate and separate the excess unreacted carbonate by filtration. Then the filtrate was boiled down to dryness. It was a lot of work that took a full week in order to complete the process. I performed a really bulky synthesis to justify the amount of work and time spent on it....and after all these years I still have nitrate in stock from that batch.

 

In all fairness it should work just about the same with strontium, but I have not personally tried this with Sr carbonate. So perhaps there is a chemical reason for this not working with strontium carbonate...perhaps it is that much less reactive in these conditions....

 

I've also made calcium and sodium nitrate by reacting the respective carbonates with AN by just heating the combined salts in a pot over a gas heater. Very unhealthy and unsafe approach, but it worked as per plan. In this day and age I would not waste AN on turning it into metal nitrates this way. But back in the day AN was the only nitrate available in pure form and it cost almost nothing. So it made sense to utilise it for the production of other nitrate salts.

[SeaMonkey]

It is possible to make Nitric Acid from Air with Electrical Discharge.

Very much like it was, or still is, done in Norway, except on a smaller

scale. The Acid won't be as strong as the commercially available

Nitric Acid but more than adequate for making various Nitrate Salts.

 

There are several YouTube videos which show how easy it is to

make Nitric Acid from Air. Granted, it takes several days, weeks or

months of continuous operation to prepare a sizable amount of the

Acid, but the cost is very low and, given enough time, the quantity

is unlimited.

 

For those in areas where Nitric Acid isn't available for purchase, this

method enables an alternative, inexpensive source.

[THEONE]

I got kno3 and 30% H2SO4 and maybe i will just mix the two and boil them down transferring the products to an ice-cold suspension with Sr carbonate through a Teflon tube. Just an idea

Edited February 13, 2020 by THEONE

[SeaMonkey]

TheOne,

 

That will work. Boiling the Nitric Acid vapors through a tube into the suspension

should do the trick. You may also use Muriatic Acid (Hydrochloric Acid) in

place of the Sulfuric Acid if you desire provided you use just enough to

react with the Nitrate salt so as not to have an excess of Muriatic in the

solution you are boiling. Sulfuric Acid is definitely safer.

 

If you have Calcium Nitrate it can be used to make a dilute solution of

Nitric Acid with Sulfuric Acid as well. The advantage of the Calcium Nitrate

is that the solid reaction product Calcium Sulfate is insoluble and will

settle to the bottom of the solution. Then the dilute Nitric Acid can simply

be decanted off or filtered without a need for boiling.

Edited February 14, 2020 by SeaMonkey

[Mumbles]

I'd be worried about incorporating sulfates if not distilling off the nitric first. They'd react with your strontium salts to produce very insoluble strontium sulfate. The calcium nitrate prep does help minimize that.

 

The hydrochloric acid prep is tricky. On one hand, HCl is a stronger acid than nitric acid. In the other, HCl can more easily be volatilized out of the solution, driving things backwards. I believe dichloromethane has been used to extract the nitric acid. This is an extra step and makes it less convenient and less economically viable.

 

Some hydroponic pH lowering solutions are dilute nitric acid.

[Piccaso]

I would love to make my own nitric acid. No one around me sells it over the counter and the shipping costs are stupid. I have plenty of concentrated sulfuric acid and understand there is a way to do it but I do not have the process.

Edited February 15, 2020 by Piccaso

[SeaMonkey]

For many Nitrations a mix of Sulfuric Acid and Nitric Acid

is used. The typical ratio is 60% Sulfuric Acid and 40%

Nitric Acid.

 

I generally make this with Concentrated Sulfuric Acid and

Solution Grade Agricultural Calcium Nitrate prills. I pour

a quantity of Calcium Nitrate prills into a suitable bottle

then cover the prills with the concentrated Sulfuric Acid

just over the top of the prills. I then set the capped bottle

aside for several days until the reaction completes and

the resultant Calcium Sulfate settles to the bottom of the

bottle. The mixed acid will be a clear solution which can

be carefully poured off to separate it from the bottom

layer of Calcium Sulfate.

 

This mix of Sulfuric Acid and Nitric Acid works very well for

Nitration of Cellulose, Starch or various Sugars.

 

The mix could also be distilled if desired to separate out

the concentrated Nitric Acid.

 

I haven't seen this procedure on any YouTube video yet

but it is very old and one I've always used.

[greenlight]

@ Picasso, do you have access to lab ground glass distillation apparatus?

You have the concentrated sulfuric acid and the only other thing that is required is potassium or sodium nitrate.

You make a mixture of the salt to acid and just collect the ~90% nitric acid that comes over upon distillation. This can be diluted down if needed or concentrated even more by vacuum distillation to produce 99% water white HNO3.

There is probably much info elsewhere on the internet on this.

Edited February 16, 2020 by greenlight