macropause
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Cleaning crucibles
Hello everybody,
I have a problem with cleaning crucibles. I've melted LiFeVPO4 in alundum crucible and I have no idea how could I remove the solified
substance from it. Have anyone of you ever coped with it?
Thanks in advance for any help.
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blogfast25
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Quote: Originally posted by macropause  | Hello everybody,
I have a problem with cleaning crucibles. I've melted LiFeVPO4 in alundum crucible and I have no idea how could I remove the solified
substance from it. Have anyone of you ever coped with it?
Thanks in advance for any help. |
Melt it again and cast it onto cold marble slab? What's LiFeVPO4 good for?
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bfesser
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<strong>blogfast25</strong>; batteries.
<strong><a href="http://www.physics.rutgers.edu/~croft/papers/180-LiFeVPO4-jp2034906.pdf" target="_blank">Effect of Vanadium Incorporation
on Electrochemical Performance of LiFePO<sub>4</sub> for Lithium-Ion Batteries</a></strong> <img src="../scipics/_pdf.png"
/>
<strong><a href="http://search.proquest.com//docview/305106875" target="_blank">Synthesis and characterization of high performance
electrode materials for lithium ion batteries</a></strong> <img src="../scipics/_ext.png" />
Sorry, I have no advice for cleaning your expensive crucible, <strong>macropause</strong>. I've been scanning the lit. since you posted,
but haven't found anything yet. I'd imagine that the vanadium will make little difference, so if you find anything in the experimental section of a
paper on LiFePO<sub>4</sub>, it may be of use. I see a mention of a carbon-coated alumina crucible used for this, perhaps to protect the
crucible from the melt (<a href="http://link.springer.com/article/10.1134/S1023193512110055" target="_blank">source</a> <img
src="../scipics/_ext.png" /> . <a href="viewthread.php?tid=11021">This
thread</a> may give you some ideas on what you could try without dissolving your crucible.
[Edited on 6.8.13 by bfesser]
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watson.fawkes
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As blogfast25 said, melt it again. Crucibles are refractory for holding materials at heat. They are not casting molds for allowing
the melt to solidify (as you've discovered). You can make an ad-hoc ingot mold by pressing a form into a pan of sand.
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macropause
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Melting it again is, unfortunately, bad idea, because it will solidify on the lateral surface of crucible before flowing out of it - and I want the
crucible to be perfectly clean.
I guess I try to dissolve LiFeVPO4 with Aqua Regia or other acids - as someone discovered in one of topics sent by bfesser,
Al2O3 doesn't dissolve very quickly.
Thank you all for your answers and ideas
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watson.fawkes
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And just how is that?
The charge is above its own melting point. The crucible is above that melting point. Presumably the crucible has enough heat capacity not to cool
below the melting point before you can pour everything out. The only thing remaining is any droplets stuck on by surface tension, but that's the best
case scenario. You may need some acid cleaning afterwards if you want "perfectly clean", but it's a lot easier to do that for only a few milligrams of
material than a whole crucible charge.
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