Acuarey
Harmless
Posts: 3
Registered: 7-10-2015
Member Is Offline
Mood: No Mood
|
|
Making CaCO3 or CaSO4 in a simple way?
First, sorry for my English.
Second, sorry for my Chemestry (Still in High shcool) ;-;
My question is:
If I mix some Sodium Bicarbonate with some Calcium Oxide(In water or heating it up, maybe ), is it possible for me to get Calcium Carbonate and Sodium
Hydroxide?
NaHCO3 + CaO ---> CaCO3 + NaOH ???
Yes? No? Maybe?
Any suggestions on how to get to that Substance(CaCO3)?
Btw, CaO + 2H2O --> Ca(OH)2 + H2
Ca(OH)2 + H2SO4 --> CaSO4 + 2H2O
Is it doeble just mixing them?
[Edited on 7-10-2015 by Acuarey]
|
|
|
Bert
|
Thread Moved
7-10-2015 at 13:45 |
Upsilon
Hazard to Others
Posts: 392
Registered: 6-10-2013
Member Is Offline
Mood: No Mood
|
|
Calcium oxide can't exist in aqueous solution because it reacts with water to form calcium hydroxide, which itself is insoluble. But calcium carbonate
and calcium sulfate are both commodity chemicals that are readily available. If you want to make them then you'll need some water-soluble calcium
salt, such as calcium nitrate or calcium chloride (which are also both commodities).
If you're able to get your hands on calcium oxide and sulfuric acid, I'm sure you'll have no trouble finding these other chemicals.
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
Limestone is Calcium Carbonate, although (usually) very impure.
White sea shells from the beach are better.
Rub away anything on the shells that is not White, and you have reasonably pure Calcium Carbonate.
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
No idea about Sodium Hydroxide, other than to try electrolysis with sea water.
Potassium Hydroxide usually works OK when you need Sodium Hydroxide, and you can get that from the ashes of a wood fire.
Last time i tried, i got ~11g of highly contaminated KOH from the ashes of the wood we burned on our stove in 1 evening (guess: 15kg wood ?)
|
|
|
violet sin
International Hazard
Posts: 1480
Registered: 2-9-2012
Location: Daydreaming of uraninite...
Member Is Offline
Mood: Good
|
|
Slacked lime( agricultural lime, Ca(OH)2) can be found in many garden stores, is CHEAP!!! I got 10 lbs the other day for 1.98$US. if you
mix it with vinegar, you get calcium acetate which is also a soluble Ca source.
Wikipedia: https://en.wikipedia.org/wiki/Calcium_hydroxide
Limewater turns milky in the presence of carbon dioxide due to formation of calcium carbonate, a process called carbonatation: Ca(OH)2 + CO2 →
CaCO3 + H2O
|
|
|
ave369
Eastern European Lady of Mad Science
Posts: 596
Registered: 8-7-2015
Location: No Location
Member Is Offline
Mood: No Mood
|
|
Calcium hydroxide isn't insoluble, it is weakly soluble. And it does react with any carbonate, precipitating calcium carbonate.
Smells like ammonia....
|
|
|
Upsilon
Hazard to Others
Posts: 392
Registered: 6-10-2013
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by ave369  | | Calcium hydroxide isn't insoluble, it is weakly soluble. And it does react with any carbonate, precipitating calcium carbonate.
|
Well, you can say pretty much everything is soluble to some extent. For this purpose it is essentially insoluble; to carry out the reaction you
mention, you would need dozens of liters of water to dissolve an appreciable amount of calcium hydroxide. This is simply not practical compared to
other methods.
|
|
|
MeshPL
Hazard to Others
Posts: 329
Registered: 20-4-2015
Location: Universe
Member Is Offline
Mood: No Mood
|
|
Nope!
Ca(OH)2 + Na2CO3 --> CaCO3 + 2NaOH is a fine and working reaction.
There may be a tiny amount of Ca(OH)2 dissolved in water at once, but if you dump some sodium carbonate (I think carbonate will be better than
bicarbonate, to obtain it you can just heat up NaHCO3 enough) and calcium hydroxide into water, everything will react according to those reactions.
Although there is a limited amount of calcium hydroxide in water at once any hydroxide present will react with carbonate and percipitate leaving space
for more hydroxide to dissolve. Eventually you will be left with NaOH solutiom and calcium carbonate percipitate.
In fact this is a historical method, which is very useful if you have no aparature and very crude materials available.  But the calcium carbonate was jus a byproduct...
The main thing produced was sodium hydroxide.
Also you can just:
CaO + H2SO4 --> CaSO4 + H2O
Careful! It's highly exothermic!
Unless you want to expore chemistry none of those reactions are usefull to you, if you manage to get sulphuric acid you can get anything else.
[Edited on 8-10-2015 by MeshPL]
[Edited on 8-10-2015 by MeshPL]
|
|
|
Upsilon
Hazard to Others
Posts: 392
Registered: 6-10-2013
Member Is Offline
Mood: No Mood
|
|
I see how that can work, but I still feel like it would be a pain. I have problems with precipitation reactions even when both substances are fully
dissolved, simply because unreacted solution gets trapped in the pores of the precipitate. It would take a lot of stirring at the very least.
|
|
|
zed
International Hazard
Posts: 2283
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
Member Is Offline
Mood: Semi-repentant Sith Lord
|
|
Well, you can bubble CO2 through a Calcium Hydroxide solution. That should get you your CaCO3. Used to be a standard analytical technique for Barium
Hydroxide (Calcium's cousin).....take a tube and blow your respiratory exhalation, through a Barium Hydroxide solution, and Insoluble Barium
Carbonate "snows" down.
Sodium Sulfate plus Calcium Hydroxide solution, should produce Calcium Sulfate nicely.
But, if you just need some Calcium Sulfate, Strip the paper off of some sheet rock, and you are good to go.
[Edited on 8-10-2015 by zed]
[Edited on 8-10-2015 by zed]
|
|
|
Little_Ghost_again
National Hazard
Posts: 985
Registered: 16-9-2014
Member Is Offline
Mood: Baffled
|
|
| Quote: Originally posted by zed | Well, you can bubble CO2 through a Calcium Hydroxide solution. That should get you your CaCO3. Used to be a standard analytical technique for Barium
Hydroxide (Calcium's cousin).....take a tube and blow your respiratory exhalation, through a Barium Hydroxide solution, and Insoluble Barium
Carbonate "snows" down.
Sodium Sulfate plus Calcium Hydroxide solution, should produce Calcium Sulfate nicely.
But, if you just need some Calcium Sulfate, Strip the paper off of some sheet rock, and you are good to go.
[Edited on 8-10-2015 by zed]
[Edited on 8-10-2015 by zed] |
What is sheet rock? do you mean the dry wall stuff with gypsum? I think we call it plaster board in the UK and from memory its a kind pinky orange
colour (bad description)
Dont ask me, I only know enough to be dangerous
|
|
|
j_sum1
Administrator
Posts: 6326
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
Sheet rock, Gyprock , gyb board, plaster board, drywall. All synonyms. It's good to be multilingual.
|
|
|
deltaH
Dangerous source of unreferenced speculation
Posts: 1663
Registered: 30-9-2013
Location: South Africa
Member Is Offline
Mood: Heavily protonated
|
|
The reaction does indeed work and does indeed form a sodium hydroxide solution. In fact, if you pack a column with slaked lime and pour NaCO3 solution
at the top, the solution eluting out the bottom should be extremely basic.
Industrially, a product called 'reprecipitated calcium carbonate' is made by sparging CO2 through a stirred slurry of lime in water. Even though only
a small amount of lime dissolves at any one time, because the carbonate is much more insoluble, eventually it all gets reacted.
|
|
|
Little_Ghost_again
National Hazard
Posts: 985
Registered: 16-9-2014
Member Is Offline
Mood: Baffled
|
|
| Quote: Originally posted by j_sum1 | | Sheet rock, Gyprock , gyb board, plaster board, drywall. All synonyms. It's good to be multilingual. |
Bugger I went and brought some!! stupid seeing as I have some off cuts of plaster board Grrr
Dont ask me, I only know enough to be dangerous
|
|
|
mayko
International Hazard
Posts: 1218
Registered: 17-1-2013
Location: Carrboro, NC
Member Is Offline
Mood: anomalous (Euclid class)
|
|
I recently made calcium carbonate by mixing concentrated calcium chloride and sodium carbonate solutions. The end product wasn't very exotic, but the
reaction was very interesting: for a few seconds, nothing appeared to happen; then, as I stirred, it grew cloudy and thickened into a translucent gel.
With further stirring, opaque white patches appeared, and finally the beaker was full of a thick white slush which slowly separated. Not the typical
quick precipitation I expected!
al-khemie is not a terrorist organization
"Chemicals, chemicals... I need chemicals!" - George Hayduke
"Wubbalubba dub-dub!" - Rick Sanchez
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
