marco2008gold
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Thermal decomposition of calcium carbonate.
Thermal decomposition of calcium carbonate.
In general, we heat CaCO3 to temperature of approximately 825°C it decomposes into calcium oxide and liberates carbon dioxide gas:*
CaCO3 →825°C→ CaO + CO2*
Is it possible to heat the calcium carbonate at temperatures below 825 degrees Celsius.
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Zyklon-A
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UTFSE.
There are already a few topics about this.
http://www.sciencemadness.org/talk/viewthread.php?tid=18501
[Edit] If your question is not answered there already, post it on that topic instead of starting a new one. (Or maybe someone will merge it to that
topic.)
This should not be in 'Energetic Materials', either 'beginnings' or 'Chemistry in General', I guess.
[Edited on 10-2-2014 by Zyklonb]
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macckone
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Quote: Originally posted by marco2008gold  | Thermal decomposition of calcium carbonate.
In general, we heat CaCO3 to temperature of approximately 825°C it decomposes into calcium oxide and liberates carbon dioxide gas:*
CaCO3 →825°C→ CaO + CO2*
Is it possible to heat the calcium carbonate at temperatures below 825 degrees Celsius. |
It actually needs to be higher for rapid decomposition.
You can go a little lower (10C) and get some decomposition
but it is slow. Much lower and nothing happens.
This should have been in beginnings and use the search engine.
This question has been answered before.
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bfesser
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Thread Moved
10-2-2014 at 09:49 |
Zyklon-A
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Build a charcoal furnace for large scale production or use a Bunsen burner/torch for small scale CaO production. I want to do this soon as well...
(large scale)
Here make a mini charcoal furnace.
Here make a real charcoal furnace.
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testimento
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Yes, this reaction works well with electric or coal fired furnace, but not with propane burner. I attempted to build a propane oven with 6kw burner
and it heated SS kettle red hot, but not just hot enough. No reaction at all. You'll need 900 minimum, preferably 1000C to get the reaction really
going. You won't notice it pretty much, the white CaCO3 turns grey and when you mix a little of it with water, it will become basic. You can calculate
the molar masses of carbonate and oxide and determine the weight loss quickly with simple lift scale to see when the decomposition has reached 95-99%,
then it's ready.
This works likely on every carbonate there is: sodium, potassium, magnesium, etc. the temperature may differ quite a lot, though. All of these will
make hydroxides when mixed with water. Yes, if you live in a F'up country like mine, you can make lye from soda. Most countries stock hydrated lime in
large bags for concrete making, and if you mix molar equivalents of CaOH and sodium carbonate in water, you'll get calcium carbonate and sodium
hydroxide.
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Zyklon-A
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No, it does not work with most (all?) group-1 metal carbonates. Sodium carbonate boils at 1,633°C, but does not decompose even at that temperature.
Reference:
http://uk.answers.yahoo.com/question/index?qid=2010081605160...
I know that yahoo is not the most reliable reference, but wiki shows no decomposition temperature either.
The guy who answered a least knew something, but he is wrong about something as well:
| Quote: |
Sodium oxide is produced when sodium bicarbonate is added to water. |
Oh yeah, that definitely happens....
[Edited on 11-2-2014 by Zyklonb]
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testimento
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Oh dear, then I've made a terrible mistake. Sorry for that.  It definitely
looks like sodium and potassium won't give up their carbonates by any terms of heating, but calcium and magnesium certainly does.
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Zyklon-A
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No, not a terrible mistake, just minor error, everybody make them...
I used to think that Na2CO3 decomposed at ~1200°C because Wikipedia said that, apparently that error has been fixed though.
There seems to be an enormous amount of misinformation on the decomposition of all sorts of common compounds, specifically alkali carbonates and
nitrates. Just take a look at the Preparation of ionic nitrites topic.
[Edit]
| Quote: |
Yes, this reaction works well with electric or coal fired furnace, but not with propane burner. |
Maybe not everyone's torch, but mine can get hot enough. It just depends.
[Edited on 11-2-2014 by Zyklonb]
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