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underground
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Strontium nitrate from strontium carbonate
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?
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Tsjerk
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The carbonate has to dissolve in order for it to react with ammonium. Strontium carbonate is pretty insoluble with 0.065 g/100 mL (100 °C). This
process will probably work, but you need to reflux for a very long time.
Apparently the carbonate is a bit soluble in ammonia. Ammonia is produced in the process, what I read is that the recommended procedure is to slowly
add hot ammonium nitrate solution to a hot suspension of SrCO3. Maybe the ammonium nitrate pushes the carbonate out of solution. I don't know. What
you could do is refluxing what you have now with a bit of dilute ammonia.
Or just use the nitric acid directly, but that is probably not preferable.
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underground
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Ok i will try it out
Edit:
What if i react a stoichiometric amount of AN and HCL to form NH4CL and HNO3? Then add the Sr Carbonate? I then just have to separate the NH4CL from
Sr nitrate, maybe by decomposing NH4CL
[Edited on 10-2-2020 by underground]
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Tsjerk
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The problem with that would be the formation of nitrosyl chloride, which is pretty stable and hard to get rid off.
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symboom
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You might have to convert it to strontium hydroxide the reaction will be the same as calcium hydroxide forming calcium carbonate and ammonia gas as
side products
The method you were hoping to work is with sodium carbonate and ammonium nitrate where ammonium carbonate is produced and driven off by high
temperature.
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underground
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Quote: Originally posted by symboom  | You might have to convert it to strontium hydroxide the reaction will be the same as calcium hydroxide forming calcium carbonate and ammonia gas as
side products
The method you were hoping to work is with sodium carbonate and ammonium nitrate where ammonium carbonate is produced and driven off by high
temperature. |
So if i react of Sr carbonate with NaOH, how i get out the Na carbonate?
| Quote: Originally posted by Tsjerk | | The problem with that would be the formation of nitrosyl chloride, which is pretty stable and hard to get rid off. |
nitrosyl chloride is a gas so by evaporating everything you should get rid of it right ?
[Edited on 10-2-2020 by underground]
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Tsjerk
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| Quote: Originally posted by underground |
nitrosyl chloride is a gas so by evaporating everything you should get rid of it right ?
[Edited on 10-2-2020 by underground] |
I'm not an expert on nitrosyl, but you could have a look at Woelen's posts about it. It is not a gas as you think it as as long as water is around.
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woelen
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Nitrosyl chloride is an orange/brown gas, which can exist in concentrated HCl as a bright orange solution. On dilution, this gas is hydrolyzed by the
water, forming HCl and HNO2. The HNO2 in turn slowly decomposes, giving NO and HNO3.
I personally think that ONCl is not a real problem in the above reaction. But I see no point in adding chloride in the mix as well. You make things
more complicated and more difficult to separate.
What you can try is dissolving SrCO3 in dilute HCl and boiling this down to a very saturated solution of SrCl2.
NH4NO3 also is very soluble.
If you mix the solutions (using a little excess NH4NO3) and boil down, then the first compound to precipitate may be Sr(NO3)2. This is the least
soluble. Do not expect a nice pure product though. You'll need at least one recrystallization for a reasonably pure product.
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symboom
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I was assuming to much thermal decomposition of strontium carbonate to strontium oxide then add water to form strontium hydroxide
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underground
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This reaction takes place at a temperature of 1100-1200°C.
| Quote: Originally posted by woelen | Nitrosyl chloride is an orange/brown gas, which can exist in concentrated HCl as a bright orange solution. On dilution, this gas is hydrolyzed by the
water, forming HCl and HNO2. The HNO2 in turn slowly decomposes, giving NO and HNO3.
I personally think that ONCl is not a real problem in the above reaction. But I see no point in adding chloride in the mix as well. You make things
more complicated and more difficult to separate.
What you can try is dissolving SrCO3 in dilute HCl and boiling this down to a very saturated solution of SrCl2.
NH4NO3 also is very soluble.
If you mix the solutions (using a little excess NH4NO3) and boil down, then the first compound to precipitate may be Sr(NO3)2. This is the least
soluble. Do not expect a nice pure product though. You'll need at least one recrystallization for a reasonably pure product.
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Ok i will try this out
Edit:
From the above reaction, Sr(NO3)2 and NH4CL will be formed. How should i separate them as they both got identical solubilities ?
[Edited on 10-2-2020 by underground]
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Bedlasky
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They haven't identical solubilities.
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underground
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According to wiki Sr(NO3)2 got 604.3 g/L (0 °C) and NH4CL 294 g/L (0 °C) so it is not that much big difference.
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CharlieA
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In the supplement to his "Illustrated Guide to Home Chemistry Experiments," Robert Bruce Thompson (aka The Home Scientist) started with crude
strontium carbonate from Seattle Pottery, washed it with water several times to remove any soluble impurities, and then converted it to strontium with
HCl (by products are carbon dioxide and water). The strontium chloride is then reacted with sodium hydroxide to give the insoluble strontium hydroxide
and sodium chloride. The insoluble strontium hydroxide is reacted with nitric acid to give strontium nitrate and water. The strontium nitrate is then
recovered by evaporation.
This sounds convoluted, but it is mostly tedious. Each step gives a strontium compound easily separated from the other products produced in the
reaction. So each step should give a high percentage yield of the desired product.
As an aside, why did you expect to smell ammonia (NH3) from your reaction? From your procedure, barring impurities in your chemicals and perhaps some
hydrolysis of ammonium ion, I wouldn't expect to smell any ammonia.
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clearly_not_atara
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I don't know why all of these strange ideas are necessary. The simple method should work fine. It's just a long reflux. And it's much cheaper and
easier than breaking out the hydrochloric acid.
| Quote: Originally posted by symboom | | You might have to convert it to strontium hydroxide the reaction will be the same as calcium hydroxide forming calcium carbonate and ammonia gas as
side products |
This is far more difficult than simply reacting SrCO3 with a refluxing solution of NH4NO3. SrCO3 decomposes at a whopping 1494 C! That's 500 degrees
hotter than limestone.
| Quote: | What you can try is dissolving SrCO3 in dilute HCl and boiling this down to a very saturated solution of SrCl2.
NH4NO3 also is very soluble. |
SrCl2 solubility 53.8% w/w, Sr(NO3)2 solubility 66% w/w; SrCl2 molar mass 158, Sr(NO3)2 molar mass 211. Molar solubilities 3.4 M and 3.1 M
respectively.
That's sliding in right under the wire for salt metathesis and I don't know how the solubility of SrCl2 changes with temperature. It could work or
not. NH4Cl however has a molar solubility of about 5.5 so it's nothing to worry about.
[Edited on 11-2-2020 by clearly_not_atara]
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UC235
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I have precipitated Sr(OH)2 before. Solubility is 0.41g/100ml ice cold and it comes out as the octahydrate. If the SrCO3 is pottery grade it may also
contain some barium. Preparing the chloride solution and dropping out the hydroxide constitutes a purification step since Ba(OH)2 is somewhat more
soluble.
The hydroxide should be more than soluble enough to readily react with NH4NO3.
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underground
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I want to use the Sr nitrate for pyro purposes so i guess i should use KOH right ?
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Tsjerk
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If you want a nice red, sodium is a no go as long as you're not prepared to do laborious recrystallisations.
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underground
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After searching around a bit, i have seen ppl got Barium nitrate from carbonate with the same method while it is less soluble than Sr Carb. Also, here tetrahedron use AN and Sr carbonate to make Sr Nitrate. It is really strange why my reaction does not work. Also, i noticed a bit of sulfur
smell why i was trying for it. The AN is a fertilizer grade.
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Tsjerk
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Where does your carbonate come from? Maybe it is calcinated and therefore a bit less reactive. I'm pretty sure you just didn't give it enough time.
How long did you reflux?
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woelen
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In my previous reply I assumed that you don't want to use (precious) nitric acid for this purpose, hence the somewhat involved mechanism through
SrCl2. If you are willing to spend some nitric acid, then things of course are much easier.
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underground
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Yea i don't actually want to spend my few ml of HN03. I did a mixture of 450g of 35% HCL and 400g of moistened AN. The mixture was pretty cold due to
AN dissolved into it. No heat up built at all. When almost all AN dissolved, i used a sample of that mixture to react with some copper metal and no
reaction occurred. Obviously something is wrong with that AN. Maybe they have added additives to make it unreactive or i dunno. If it did not react
with HCL then there is no possibility to react with Sr Carb.
[Edited on 12-2-2020 by underground]
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Tsjerk
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High concentration of chloride in aqua regia can lead to passivication. The fact the dissolution of your presumed AN leads to cooling of the solution
makes me think it is actually AN. What else is endothermic upon dissolving and what could possibly interfere in this reaction?
Again: my bet is on calcinated SrCO3 and a too short reaction time.
I will ask again; how long did you reflux during the first experiment?
Edit: if you refluxed at all.
[Edited on 12-2-2020 by Tsjerk]
[Edited on 12-2-2020 by Tsjerk]
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underground
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I have not a reflux device just boil it, add water and continue boilling it. About 5h
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woelen
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Are you sure that the material in the cold pack is ammonium nitrate? In many countries, this is replaced by urea. The latter also works quite well for
cooling purposes and dissolves in water very well. I get the impression that you cold pack is urea instead of ammonium nitrate.
Ammonium nitrate + conc. HCl definitely is capable of dissolving copper metal. Copper metal is one of the metals, which is not passivated by a
strongly oxidizing solution.
You could test for urea as follows:
- Heat the material until it melts, but do not overheat, just keep it in a molten state.
- the material will lose gas (bubbling).
- You will smell ammonia, quite a lot of it.
- Keep the white residue. Let it cool down, crunch to a fine powder, and dissolve in water (no problem if not all of it dissolves)
- Perform the so-called biuret test: https://en.wikipedia.org/wiki/Biuret_test
You can do this test without the tartrate, mentioned in the wiki page. Just use copper sulfate and a little alkali, you will see the purple color if
the original material is urea.
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underground
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It is a fertilizer grade and i asked about AN, there is another urea fertilizer so i really doubt it is Urea.
I just got another idea, i may react NAOH and CaCL to form the insoluble CAOH. React CAOH with AN to form CA nitrate. React h2so4 with Ca nitrate to
form the relative insoluble Ca sulfate and hno3. Filter it and react with Sr carb to form Sr nitrate. It may contain a few calcium sulfates as
impurities but it won't matter cause it is for pyro purposes. Ca and Sr got almost the same color.
CaHO should easily react with AN. If it won't then i definitely have to toss it lol
[Edited on 14-2-2020 by underground]
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