15 replies to this topic

[frosty90]

Hi,

I swear there was a thread already on this, but I could not find it (mods move/delete this if you feel so inclined):

I have barium carbonate, so I was thinking BaCO3 + 2HNO3 ---> Ba(NO3)2 +CO2 + H20
react the appropriate amounts, then test pH and bring it back up to 7 if needed with excess carbonate.
I can get 68% nitric (other dilutions are more expensive!), would you recomend diluting it first? Any special precautions for such a process (I am aware of the hazards of nitric, and soluble barium salts)?
Can anyone share their experiencees?

Jesse

Edited by frosty90, 25 February 2010 - 11:57 PM.

[MDH]

It might help to dilute the barium carbonate with distilled water first.

On the other hand, there is also synthesis through the reaction of potassium nitrate and barium acetate.

http://www.pyrosocie...barium-nitrate/

Edited by MDH, 26 February 2010 - 12:01 AM.

[mike_au]

I would dilute the acid. I would not recommend mixing the BaCO3 with water prior to mixing.

Mixing water and acid, and mixing carbonates with acid are both exothermic reactions (they release heat) that heat can cause localised boiling which can spit hot acid around the place.

Since barium carbonate is barely soluble in plain water, premixing them won't produce a solution. It would be essentially the same as throwing some carbonate in at the same time as some water. You will get significantly more heat.

Lower concentration acids will react more slowly and therefore produce heat more slowly, which is why I would recommend diluting the acid before you start.

Remember the rule "Do as you ought-a, add acid to water" (and if you can use cold water, even better).

[TheLummox]

When i did this to make my Barium Nitrate, make sure it doesnt get to hot or regardless cause mine started reacting with whatever container it was in, the nitric acid i bought was 98% or something, fuming white (no questions asked either :S). If i didnt dilute it, it would never react. I remember a mate telling me the way he does it was he would add however much nitric acid to a large hdpe bucket, then he would add an excess of carbonate, then just add water till the reaction stopped, filtered and wallah good barium nitrate.

[frosty90]

When i did this to make my Barium Nitrate, make sure it doesnt get to hot or regardless cause mine started reacting with whatever container it was in

Funny you should mention that, My bottle of acid specifically states: "If whitening or embritlement of container occurs, immediately transfer acid to another container"

(no questions asked either :S)

That is another thing that surprised me. I got mine from a chemical company who will not sell me any dichromates, elemental sulfur or even platinum wire, yet were happy to supply me with conc nitric, no questions asked!

Jesse

[phildunford]

Add the powdered carbonate to dilute acid. Keep adding until you get no more reaction and then leave to stand some more.

Filter and crystalise. Works fine but a bit tedious and slow!

Does not work well with the conc acid.

All from experience!!

[Mumbles]

It didn't react because really concentrated nitric acid does different things. It make NO2+ instead of H+ when that concentrated. There is no reason to use that concentrated of acid though. Do the nitric/BaCO3 outside as it is likely that your carbonate is just the mineral source which has noticable barium sulfide contamination, which will release H2S upon acidification. If this is the case you will also get some insoluble material. You may want to let the solution stand for a few days, as barium sulfate will precipitate out upon oxidation from air.

[frosty90]

It didn't react because really concentrated nitric acid does different things. It make NO2+ instead of H+ when that concentrated. There is no reason to use that concentrated of acid though. Do the nitric/BaCO3 outside as it is likely that your carbonate is just the mineral source which has noticable barium sulfide contamination, which will release H2S upon acidification. If this is the case you will also get some insoluble material. You may want to let the solution stand for a few days, as barium sulfate will precipitate out upon oxidation from air.

Hmm,

So how dilute? 1M, 2M? 68% is 15M i think.

Jesse

[Arthur Brown]

http://chemicalland2...IUM NITRATE.htm Says that the solubility of barium nitrate is 87g/litre So work out the mass of acid needed for the mass of barium carbonate you have then work out the mass of water to dissolve all of the barium nitrate produced. You need to keep the water mass down because the product is in the water layer and you must evaporate the water to recover the barium nitrate. This in industry means energy cost and in amateur land means time equipment and effort and energy cost.

[frosty90]

http://chemicalland2...M%20NITRATE.htm Says that the solubility of barium nitrate is 87g/litre So work out the mass of acid needed for the mass of barium carbonate you have then work out the mass of water to dissolve all of the barium nitrate produced. You need to keep the water mass down because the product is in the water layer and you must evaporate the water to recover the barium nitrate. This in industry means energy cost and in amateur land means time equipment and effort and energy cost.

Ahh ok, well i worked out: 197.3g BaCO3 +92.6g 68% nitric ---> 261.3g Ba(NO3)2

so to dissolve all the nitrate from one mol of carbonate will require about 3 litres of water! that really seems like alot, and will obviously take ages to evaporate, and the solubility doesnt drop too much with cooling, so evaporation seems like the only way to get reasonable amounts of nitrate out. could I not simply allow the nitrate to precipitate out as the reaction occurs. I.e. add the carbonate slowly? maybe put the wholecontainer in a cooling bucket of water?

Jesse

[phildunford]

Depends how much you want to make.

My totally unscientific test used about 250ml of dilute acid (1 acid to 9 water) kept on putting in carbonate until there was an excess. Filtered, put in a shallow tray and left a week or so in a warm place. Got about 20 grams of product.

This is all from memory, so don't tell me the figures don't stack up! It's about right... I have other sources now, so don't need to do this, but it was an interesting experiment and produced usable product.

[frosty90]

Depends how much you want to make.

My totally unscientific test used about 250ml of dilute acid (1 acid to 9 water) kept on putting in carbonate until there was an excess. Filtered, put in a shallow tray and left a week or so in a warm place. Got about 20 grams of product.

This is all from memory, so don't tell me the figures don't stack up! It's about right... I have other sources now, so don't need to do this, but it was an interesting experiment and produced usable product.

Hi all,

Just thought I'd report the results:

I took aprox 190g of 68% nitric, which equates to about 2 mol of HNO3. I diluted this to 1 litre, then added bit by bit almost 200g of barium carbonate. There was a slight odour of hydrogen sulfide. I found that you need to carefully add the carbonate slowly bit y bit so the efervecence doesnt casuse the solution to spill over the sides of the container. Once no more effervecence occured I stopped adding carbonate, but for some reason the pH was still around 6, I couldnt get it to 7 with aditional carbonate, there was alot of precipitated barium nitrate plus about 1 litre of solution, this was all put into a shallow container to evaporate.

Now to wait.....


Jesse

[Bonny]

http://www.pyrosociety.org.uk/forum/topic/1061-barium-carbonate-barium-nitrate/

Read this thread (last few pages). There is lots of info there. I have made barium nitrate this way several times. I use HNO3 diluted to ~25% conc. Use a glass container if possible. I use a 5l glass soup pot.
Add carbonate (in small amounts) until the rxn stops. I then stir it and let it sit for a day. Add some more carbonate (just to be sure), stir it well and allow to sit again. The low solubility of barium nitrate is pain though as much of the nitrate will be in the bottom with the white sludge of unreacted carbonate sulfate etc...
To process, heat the solution, decant the (warm/hot)water off, filter allow the water to cool, the crystals will form as the water cools. You will need to add water several times to extract all the nitrate.

Be sure to wear a mask/respirator and rubber gloves as well as some eye protection as this is a dangerous procedure.

@frosty- barium nitrate is/can be acidic in solution (ph of 5-8)
You can boil off most of the water rather than wait for it to evaporate.

Edited by Bonny, 01 March 2010 - 04:37 PM.

[Arthur Brown]

Remember that the product is in the solution and it is toxic. 87g of Barium Nitrate will dissolve in a litre of solution so you will need two litres and a bit to dissolve the barium nitrate that you have made. If there isn't that sort of volume then you have a saturated solution AND crystals of product as well as precipitated sulphide sulphate etc.

You have a vat with barium carbonate, sulphate and sulphide in the bottom which you need to filter off keeping the liquor then evaporate the liquor to dryness without scorching it. Then add a little acid to the sludge see if it fizzes If so more acid will bring some more barium nitrate out of the sludge which will need filtering and evaporating.

[frosty90]

Oh so there is likeley to be alot of sulfate in there too? If it is the usual tech grade of barium carbonate, how much of it would be sulfate? A little doenst concern me (should it? I would be using it with K chlorate and shellac), going by the quantity of raw 'carbonate' I added to the quantity of acid before it had stopped fizzing, it doesnt seem like much, the numbers seemed to add up pretty well. The acid should have destroyed all of the sufide shouldn't it? The solution still smells a little too.

Jesse

edit: Ok so I diluted my original 1L down to about 3L, heated then allowed it to settle, and decanted the liquid off the sediment (I tried filtering, but it was painfully slow.). Im now going to boil that down. I'll keep the sediment and add more water to get all the nitrate out too.

Edited by frosty90, 02 March 2010 - 05:02 AM.