73 replies to this topic

[Phoenix]

I've been looking into making barium nitrate, and I have found a method that seems to show quite a lot of promise, and I am quite surprised that more people don?t use it already. It has already made me several grams of real barium nitrate, which gave a bright, unmistakable green when I tried it in a couple of published compositions.

The basic outline of the method is to react barium carbonate with acetic acid - ordinary vinegar - to produce barium acetate, which is soluble in water. This is then mixed with potassium nitrate solution. The "ion soup" is then left to evaporate. Fortunately, barium nitrate is the least soluble of the various combinations of ions possible from the ingredients (potassium nitrate, barium acetate, potassium acetate, and barium nitrate) so is the first substance to begin crystallising out. Potassium acetate is also very soluble in water, so will remain in solution whilst this is going on. The barium nitrate crystals can then be filtered out, and purified by redissolving and crystallising.

I think that the reaction is something like this:

BaO4C4H6 + 2KNO3 --> Ba(NO3)2 + 2KO2C2H3

Therefore one needs 255g of barium acetate and 202 g of potassium nitrate to start with, giving a final yield of 196g of barium nitrate. Since crystallising out the barium acetate is unnecessary, it is simpler just to weigh out the barium carbonate, then react it with sufficient vinegar (add until reaction ceases, then add a little more barium carbonate to neutralise excess), and mix this solution with the potassium nitrate solution. When doing this, for every 202g of potassium nitrate, you should start with 197g of barium carbonate (which will react to give 255g of barium acetate). Using typical distilled vinegar, just less than two litres was required to react with barium carbonate. As I said, this is currently evaporating, so I do not know how much product I will get yet. I actually added a slight excess of potassium nitrate to the solution, in the interest of making sure that it doesn?t ?run out? before the barium acetate, to avoid having too much left behind afterwards.

I did a small trial run of the method a few weeks ago (reduced quantities), which has so far yielded a couple of spoonfuls of barium nitrate, and is still evaporating. Unfortunately, in my eagerness to experiment with this initial harvest, I did not weigh it, so cannot comment on the efficiency of the method. However, I have just started a ?production sized? batch, which will give an ideal yield of 392g of barium nitrate. I will let you know how much I actually get in a couple of weeks.

Finally, make sure that you have some potassium or magnesium sulphate solution on hand whilst doing this, so that any spilled barium compounds can be rendered safe with it, and since there is bound to be some barium left in the potassium acetate solution, this should be made safe with a sulphate too. Since the resultant barium sulphate and potassium acetate are not particularly dangerous, this solution/suspension can probably be safely disposed of down the drain. (For anyone who didn?t know, barium sulphate is almost totally insoluble, and not terribly reactive, and therefore does not pose a serious danger. Adding a soluble sulphate to a soluble barium salt will cause the barium to be precipitated out as barium sulphate).

I may well have added a few things up wrong or made other mistakes, so I welcome any suggestions people have for improvement, and maybe I have missed some issue that causes it not to be generally used (I can?t really believe that I am the first person to try it), but I have made several grams of barium nitrate in this way, which did definitely work as it was supposed to. Whilst this method may be a little less efficient than reacting barium carbonate with nitric acid or ammonium nitrate, it does seem to work, and uses readily available chemicals, so may be of use to some people.

[miniskinny]

Well, while I am new to pyrotechnics and chemistry (haven't taken it yet in high school!), I do not see any problems in your research, and I am quite excited to try this myself! I will follow your instructions exactly, to ensure safety; Thanks bunches! As you may know, Barium nitrate is unshippable by Skylighter currently, and U.N. (United Nuclear) sells it for much more than Skylighter does.

[Phoenix]

Don't treat my instuctions as guarunteed to be safe - they are just a description of the method. I didn't mention, avoid getting any barium componds on your skin, and wash them off immediately if you do. Using barium in this way does carry some risk, and whilst careful, common sense practice should keep you safe, do this at your own risk!

[alany]

I just tried it. I think my barium carbonate must have some sulfate in it, as I added the acetic acid (technical 9% solution) it gave of a strong odor of hydrogen sulfide. There was a small amount of insoluable residue and the solution was slightly milky no matter how long I boiled it.

I dumped in the potassium nitrate and boiled down the solution a bit, then filtered it. The filtering got rid of the insoluable junk and a bit of the milkyness, but I didn't use a high quality filter so I didn't expect to get rid of any of the finer suspended barium sulfate.

It is crystalising now, I'll tell you how it goes.

[Phoenix]

Yes, I experienced the same hydrogen sulphide odour, and persistant cloudiness. I didn't bother to boil or filter it, I'm just letting it crystallise and I'll do the filtering later, when I redissolve and purify the crop. All the cloudiness soon settled out and left a clear solution, so it shouldn't be too hard to decant the barium nitrate solution off the impurities, even if they won't filter out.

One thing I didn't mention before, it's a good idea to wear goggles whilst you are adding things and stirring it around, and especially if you were to boil it. I also conducted the vinegar + BaCO3 reaction outside, and downwind of me, so that I didn't inhale any of the barium mist that resulted from it frothing up. Same would apply for boiling.

[Patrick]

Well, while I am new to pyrotechnics and chemistry (haven't taken it yet in high school!), I do not see any problems in your research, and I am quite excited to try this myself! I will follow your instructions exactly, to ensure safety; Thanks bunches! As you may know, Barium nitrate is unshippable by Skylighter currently, and U.N. (United Nuclear) sells it for much more than Skylighter does.

Barium Nitrate is shippable through Firefox as a hazardous material, but still shippable.

[phildunford]

After a lot of trial and error, I managed to make Barium Nitrate using the carbonate and dilute Nitric Acid. However I also noticed the Hydrogen Sulphide smell. It's been discussed here before and 'ceramic suppliers' claim their Carbonate is 'pure'. However this does not seem to be the case. If sulphides are present there is a risk (of explosion) if the substance is used with Chlorates. Probably small, but worth thinking about...

[Phoenix]

True, but they apparently leave the barium nitrate as hydrogen sulphide. Barium sulphate won't do this, but as it's insoluable, it's left behind when the solution is filtered or decanted, so the sulphur containing impurities should be minimal.

[pyrotechnist]

Cool so does this take long to do? Also does the other impurities crystalise or do the like stay watery? If they don't how do you know what is barium salt and what is the other chemical or do you add a chemical to disolve the other salts? Thanks .

[Phoenix]

How long it takes depends largely on how warm the solution is (and therefore how fast it evaporates). The part that you are actually involved in (weighing, dissolving and mixing the chemicals) only takes about 20 minutes, but the evaporation may take a couple of weeks. Fortunately, you can just leave it somewhere safe and forget about it while it does that.

The idea is that as the solution evaporates, the barium nitrate begins to crystallise out, as it is not very soluble. However, the potassium acetate is extremely soluable, so remains dissolved in the water. Once the correct amount of water has evaporated, most (or ideally all) of the barium nitrate will have formed crystals, but most (or, of course, ideally all) of the potassium acetate will still be dissolved in the water. The creystals of barium nitrate can be filtered out, thus seperating the barium nitrate from the impurities. The process is almost the same as making potassium chlorate from sodium chlorate and potassium chloride.

Barium nitrate forms small, white granular crystals, which look very much like common salt or sugar. You lust allow it it evaporate until you have a reasonably thick layer of white crystals on the bottom of your container, and then filter them out. You can then continue to evaporate and filter it until you have collected as much barium nitrate as you expected to (see my original post). To test if it is barium nitrate, an effective way is probably just to make a small sample of a green colour composition with it and see if it works. Alternatively, you could mix some of it with a sulphate solution (Mg or K). If it is a barium salt (barium nitrate rather than potassium acetate) a dense white precipitate will form.

Incidentally, I did try to go about this in the same way as for making potassium chlorate (boiling and cooling), but found that the potassium nitrate crystallised out instead, whereas evaporating the water slowly gives barium nitrate.

[Andrew]

Hi
my favorite method for this conversion has been adding BaCO3 in small amounts to dilute nitric acid. When the nitric acid is completely consumed, no more BaCO3 dissolves, a very simple and effective indicator. you are left with a Barium Nitrate solution, an excess of the carbonate is added to ensure completion and is then filtered, the water is evapourated to leave Ba(NO3)2. However getting hold of nitric acid can be a bit of pain. I am interested to try the recrystalisation method as I'm sure it will be cheeper.

Andy

[Phoenix]

Hi,

When I started this topic I said I'd post the results of my larger batch of barium nitrate when the solution had evaporated sufficiently in "a couple of weeks." Well, it's been a long couple of weeks, but the bottom of the tray of solution is now covered in a layer of crystals, which I think (hope) is my barium nitrate beginning to crystallise out.

[BigG]

I watched this space with some interest now ? the usage of vinegar is an interesting idea ? and I think it is worthwhile to send your material to laboratory analyse.

One must mention, that there is another simple conversion that is used commercially and is visible to the home brawer. That is of barium chloride + sodium nitrate. Availability of hydrochloride acid is good ? so one could covert barium carbonate to chloride and then mixes it with a sodium nitrate solution. Of course ? the mix of hydrochloride acid with anything is dangerous and should be done with appropriate protective closing, glasses and gloves. The final material might have to be washed a few times to rid of any sodium impurities.

Please let me know the results of your experiment.

[Steve]

Barium is mined from Barytes (Barium sulphate) and then converted to the carbonate, and so to get a completly sulphate free Barium carbonate will be very expensive as the sulphate and carbonate ions are fairly similar and difficult to seperate in this situation. Also Hydrogen Sulphide has a very strong odour and so you will be able to detect very small quantities of the sulphate ion by this method.
The sulphur-chlorate issue is also deeper, When mixing Barium salts with Potassium chlorate it is possible to get ion exchange resulting in small particles of Barium Chlorate, which in the presence of sulphur or aluminium can lead to very sensitive compositions.

--

After a bit more reading, there is a second Barium ore, Witherite (Barium Carbonate), which if you can find a supplier who purifies this ore instead of converting Barytes it should have considerably less sulphate. Although I can just imagine the responce from a ceramics supplier when asked if their Barium carbonate is from a Barytes or Witherite ore.

[Phoenix]

Correct me if I'm wrong on this, but barium sulphate would not react with acetic acid. Rather it would remain as an insoluble sediment, which was definitely present, and was, in my experience, fairly easily seperated from the solution by decanting.

I suspect that the hydrogen sulphide smell comes from the reaction of vinegar with barium sulphide. Barium sulphide is really no better to have in the mixture than barium sulphate, but since you can smell it, that means it is reacting to form H2S, which bubbles off and blows away, and barium acetate, which is what you want.

All in all, the final product should be pretty low in sulphur compounds. One thing to remember is that even if this process doesn't get rid of any of the sulphur (which, if the above is correct, it does) it still doesn't put any more in, so the barium nitrate produced should be no more dangerous to use with chlorates than the original barium carbonate.

BigG - I hadn't heard of the method you outlined, but it does indeed sound like it would work on a home production scale. I know the vinegar method works to some degree, but I don't actually know how good the yield is yet. If it turns out to be crappy, I'll give the hydrochloric acid method a try.

Edited by Phoenix, 17 January 2005 - 06:32 PM.