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#Post#: 1732--------------------------------------------------
Re: an accelerator for calsium oxalate formation
DIR By: rasool083
Date: December 28, 2012, 6:57 am
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it must work in factory and I must have some powder that mix
with water there and then I can see result then.
how I must test it?
#Post#: 1733--------------------------------------------------
Re: an accelerator for calsium oxalate formation
DIR By: Michel
Date: December 28, 2012, 9:03 am
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I think you need to dissolve the CaCO3 before going on with the
reaction, else it might be uneconomical. why not try Shiva's
suggestion, or do you not have HCl solution?
--- Quote from: rasool083 link ---
>
> it must work in factory and I must have some powder that mix
with water there and then I can see result then.
> how I must test it?
>
--- End Quote ---
you can do a pilot test in the lab then see how it goes
#Post#: 1735--------------------------------------------------
Re: an accelerator for calsium oxalate formation
DIR By: Shiva
Date: December 28, 2012, 9:51 am
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or you can use dilute sulfuric acid on the surface which will
leave poorly soluble Calcium sulfate on the surface. Then, you
need not to add oxalic acid after all. Again, try on the sample
first.
Shiva
#Post#: 1736--------------------------------------------------
Re: an accelerator for calsium oxalate formation
DIR By: rasool083
Date: December 28, 2012, 9:56 am
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I have some limitation.one of them is that I must do all
reaction in one step
I was test oxalic acid and it was good.but in the higher speed
the quality will decrease,
I am thinking if I can have an accelerator in the process it
will work in high speed condition
I can not divide it in to tow separate step
#Post#: 1737--------------------------------------------------
Re: an accelerator for calsium oxalate formation
DIR By: rasool083
Date: December 28, 2012, 10:17 am
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the calcium oxalate must bonded on the surface of stone so I
must rub the oxalic acid in the form of brick on the stone in
present of water
do you have any question about it?
#Post#: 1739--------------------------------------------------
Re: an accelerator for calsium oxalate formation
DIR By: Michel
Date: December 28, 2012, 11:42 am
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try grinding the CaCO3 brick surface to very fine particles; ie
decrease the individual particle size so the reaction rate can
be higher. add little quantities of dilute HCl intermittently on
the brick surface, then add the oxalic acid
#Post#: 1742--------------------------------------------------
Re: an accelerator for calsium oxalate formation
DIR By: rasool083
Date: December 28, 2012, 1:37 pm
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could I add a HCl salt to oxalic acid brick ? I can not using
liquid.perhaps I can using a salt that release HCl in the water
what is the HCl duty?
#Post#: 1743--------------------------------------------------
Re: an accelerator for calsium oxalate formation
DIR By: Michel
Date: December 28, 2012, 2:14 pm
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I was suggesting adding HCl solution to increase the
concentration of Ca2+, so that the rate of the reaction is
increased
the HCl solution will react with the CaCO3 to produce CaCl2
which will precipitate calcium oxalate on adding oxalic acid.
however since addition of HCl solution will most likely degrade
your marble further, you can try adding a layer of ammonium
oxalate to the marble sample. the ammonium oxalate solution has
a neutral pH and will not decompose the stone. it will react
with the calcium carbonate to precipitate a film of calcium
oxalate on the surface of the marble.
Ammonium carbonate, the other product of this reaction is
immediately decomposed and the film of Calcium oxalate remains.
What do you think?
#Post#: 1744--------------------------------------------------
Re: an accelerator for calsium oxalate formation
DIR By: Shiva
Date: December 28, 2012, 2:23 pm
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Yes Mich. Instead of Ammonium oxalate, what about using Sodium
oxalate? as the side product ammonium carbonate decomposes
slowly into ammonia. I'm sure none likes it.
Shiva
#Post#: 1745--------------------------------------------------
Re: an accelerator for calsium oxalate formation
DIR By: Shiva
Date: December 28, 2012, 2:37 pm
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Also, oxalate compounds are cheaper than Oxalic acid. I tell you
what Rasool, the problem with your reaction is Calcium carbonate
-AN INSOLUBLE SALT. Of course, you will get Calcium oxalate on
the surface but the reaction won't be a complete one. It is just
like dissolving Calcium carbonate in sulfuric acid. As Insoluble
compounds are on both sides (reactants & products), it will slow
down your reaction and the reaction may not be completed.
Shiva
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