DalisAndy
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Chalk purification
How would I go about purifying calcium carbonate in children's chalk? It should make a handy reagent.
Elements Collected: 19/81 (Excluding all radioactive, using placecard for those)
Any tips or good sources are welcome.
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blogfast25
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Not all children's chalk is CaCO3, some of it is Gypsum. Test using a bit of acid.
But CaCO3 is a pretty useless reagent, actually.
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DistractionGrating
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Isn't CaCO3 useful as a primary standard for determination of calcium by EDTA titration?
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blogfast25
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Among other things, yes. Highly pure, so-called precipitated CaCO3 is used for it. Highly pure metals (dissolved in acid) like Al, Zn or Pb have also
been used as standards.
Another analytical uses (at least at the time) is the extraction of alkali metals from minerals like Lepidolite.
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DalisAndy
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Yep that was my aim with it. Cause it's the sulfate anion more reactive that carbonate anion?
Elements Collected: 19/81 (Excluding all radioactive, using placecard for those)
Any tips or good sources are welcome.
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blogfast25
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WHAT was your aim?
The second sentence makes no sense whatsoever. 'Reactivity' is a very relative term and depends entirely on chemical CONTEXT.
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Dan Vizine
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Quote: Originally posted by blogfast25  |
WHAT was your aim?
The second sentence makes no sense whatsoever. 'Reactivity' is a very relative term and depends entirely on chemical CONTEXT. |
Ahhh...I missed that. Good to be back.
But, seriously, why devote any time to this, because you can buy it so cheaply? There are lots of better things to recrystallize than CaCO3.
"All Your Children Are Poor Unfortunate Victims of Lies You Believe, a Plague Upon Your Ignorance that Keeps the Youth from the Truth They
Deserve"...F. Zappa
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blogfast25
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Yeah, hydrothermal methods aren't easy! 
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aga
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Not all "Children's Chalk" is calcium carbonate anymore.
I bought a box and it's all calcium sulphate or hard white stuff that isn't calcium carbonate.
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