Sciencemadness Discussion Board - Need help with BaSO4..

Need help with BaSO4..

dawsonsuen - 6-8-2015 at 07:44

I have recently mistakenly bought some BaSO₄ and I was just wondering if there are any ways of turning this rather inert salt into a more reactive/soluble form of Barium like BaCl₂?
I know there is a way of making BaCl₂:
BaSO₄ + 4C → BaS + 4CO
BaS + 2HCl → BaCl₂ + H₂S
But this reaction involves a temperature of about 700-1000°C...
So if there is another more practical way of converting the BaSO₄ into something more useful, please reply!
Thank you in advance

.
For more advanced reading for the reaction above:
http://samwoochem.en.ec21.com/Barium_Sulfate_BaSO4--1_325056...

[Edited on 6-8-2015 by dawsonsuen]

gdflp - 6-8-2015 at 07:52

There is wealth of information on this forum and many questions have already been answered. Rather than using the forum search engine, which is terrible, use google and limit the sites it searches. Searching https://www.google.com/search?q=barium+sulfate+site%3Awww.sc... gives http://www.sciencemadness.org/talk/viewthread.php?tid=3966 as the first result.

blogfast25 - 6-8-2015 at 08:03

Quote: Originally posted by dawsonsuen

I have recently mistakenly bought some BaSO₄ and I was just wondering if there are any ways of turning this rather inert salt into a more reactive/soluble form of Barium like BaCl₂?
I know there is a way of making BaCl₂:
BaSO₄ + 4C → BaS + 4CO
BaS + 2HCl → BaCl₂ + H₂S
But this reaction involves a temperature of about 700-1000°C...
So if there is another more practical way of converting the BaSO₄ into something more useful, please reply!
Thank you in advance

.
For more advanced reading for the reaction above:
http://samwoochem.en.ec21.com/Barium_Sulfate_BaSO4--1_325056...

[Edited on 6-8-2015 by dawsonsuen]

There really are no good options with BaSO4 because it's so insoluble.

Sulphates like CaSO4 can be reduced to sulphides with Al powder and there is no reason why this wouldn't work for BaSO4:

BaSO4 + 8/3 Al === > BaS + 4/3 Al2O3

The mixture is lit much in the same way as a classic themite reaction and burns very, very hot.

After cooling the BaS + 4/3 Al2O3 mixture would be ground up and treated with HCl (lots of H2S will evolve, so be careful! Toxic!) and the lixiviate will contain BaCl2 and some AlCl3, which can be separated fairly easily.

But this is not an easy method nor without dangers.

[Edited on 6-8-2015 by blogfast25]

dawsonsuen - 6-8-2015 at 08:31

blogfast25: Thank you for your response, I will definitely try that when I have the appropriate equipment for your suggestion.
gdflp: So.. I'm guessing heating a saturated solution with barium sulfate is that way out...?
Na2CO3 + BaSO4 --> Na2SO4 + BaCO3 ?

gdflp - 6-8-2015 at 08:40

Quote: Originally posted by dawsonsuen

gdflp: So.. I'm guessing heating a saturated solution with barium sulfate is that way out...?
Na2CO3 + BaSO4 --> Na2SO4 + BaCO3 ?

Yes, prepare a solution of saturated sodium carbonate at boiling, add in the barium sulfate, boil it for approximately 15 min, and filter off the solids. Repeat this twice more with the collected precipitate, after the last treatment, rinse the precipitate thoroughly with distilled water. This, according to that thread, should be nearly pure barium carbonate. If it does not fully dissolve upon treatment with acids, simply filter the undissolved barium sulfate.

dawsonsuen - 6-8-2015 at 08:45

Thanks! I will do that tomorrow.
Just wondering, would NaHCO3 work?

annaandherdad - 6-8-2015 at 08:47

So many interesting things on SM! I wonder if this is how the Curies, who precipitated their radium as a sulfate along with the barium, converted it into a chloride (which they then used for fractional crystallization).

chloric1 - 6-8-2015 at 08:47

if you go the route of boiling the barium sulfate in sodium carbonate, don't you need like 15 times the molar amount of sodium carbonate to drive the equilibrium forward?

annaandherdad - 6-8-2015 at 08:57

Quote: Originally posted by dawsonsuen

Thanks! I will do that tomorrow.
Just wondering, would NaHCO3 work?

Donno, but if you don't have the carbonate you can easily convert NaHCO3 into the carbonate by heating it in the oven. Probably get better quality Na2CO3 this way than you would get by buying washing soda.

dawsonsuen - 6-8-2015 at 08:58

Um... would you mind explaining why I would need 15x the molar amount of Na2CO3?
Thank you.

blogfast25 - 6-8-2015 at 09:41

I doubt if that displacement method will work: BaCO3 is actually almost 10 times more soluble than BaSO4 (Ks resp. 1.1 x 10-10 (sulphate) and 2.6 x 10-9 (carbonate) (both Wiki)).

[Edited on 6-8-2015 by blogfast25]

gdflp - 6-8-2015 at 10:31

I'm a little confused too as to why a reaction occurs. It is referenced however in this paper http://nvlpubs.nist.gov/nistpubs/nbstechnologic/nbstechnolog... There is also a patent which mentions the process and claims that the addition of phosphoric acid improves the efficiency and requires less of an excess of sodium carbonate http://www.google.com/patents/US3726963

IrC - 6-8-2015 at 11:02

Attachment: US3726963.pdf (108kB)
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gdflp, That patent also references 3 more patents which may also be useful to study.

3322683 Aqueous barium carbonate dispersions, process for their production, and dry pre-mix 1967-05-30 Lester

3304155 Process for the production of barium carbonate from barium sulfate 1967-02-14 Zimgiebl

2440641 Process of obtaining barium carbonates 1948-04-27 Minnick

Attachment: US3322683A.pdf (332kB)
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Attachment: US3304155A.pdf (119kB)
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Attachment: US2440641A.pdf (246kB)
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Two of these reference a couple more worth reading.

2211796 Manufacture of alkali earth carbonates 1940-08-20

Attachment: US2211796A.pdf (222kB)
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1615515 Process for making barium carbonate 1927-01-25

Attachment: US1615515A.pdf (83kB)
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Pumukli - 7-8-2015 at 01:40

The trick may be in the temperature setting. Above 100 C the sulphate to carbonate conversion is reportedly preferred, under this temp the reverse is true.
The contradiction based on the solubility data may arise from that those solubilities may be referenced to 25C or so.

The second linked patent does say that if there's no quick cooling and processing thereafter then reconversion of the carbonate to sulphate can be considerable.

nezza - 8-8-2015 at 23:55

I can confirm that boiling Barium sulphate with Sodium carbonate does give some Barium carbonate as I have carried this experiment out years ago, before the internet and the only Barium salt I had access to was Barium sulphate. Some of the precipitate left does dissolve in dilute HCl or HNO3 and then reacts as Barium ions should with sulphate and chromate. Basically my method was :-

Boil with Na2CO3.
Filter suspension.
Add HCl to precipitate.
Filter and add xs Na2CO3 to the solution. This precipitates out any BaCO3.
Filter. The precipitate is BaCO3.
Repeat step 1.
The yield is rather low but it was my only route to Ba++ in solution.