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Dwarvensilver
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Thanks for the links, I have the PDF now and will read.
I looks amight complicated to put together,  Hmmm 1000L flask eh, Think Dr. Bob
can get one? 
There is nothing more useless than doing well that which need not be done at all.
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wg48
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Quote: Originally posted by Dwarvensilver  | Thanks for the links, I have the PDF now and will read.
I looks amight complicated to put together, Hmmm 1000L flask eh, Think Dr. Bob
can get one? |
Yes its lot more complicated than leaving a solution to evaporate slowly.
Initially I was curious as to how they managed to grow such large perfect crystals in months and not years. Their method does seem achievable in a
diy/garage setting. Not necessarily with 1000l of solution but say 5l should be achievable. Its not much more than temperature control and circulation
with filtering.
The growing chamber could be polypropylene with peristaltic pump for circulation. If a sub micron filter is required that could be expensive as it
will need to be large to get a reasonable flow rate.
To prevent nucleation the circulating solution prior to passing through the pump and filter needs to be heated above the saturation temperature of the
solution. It must then be cooled back down to the chamber temperature before reentering the chamber. That will be relatively easy provided the
chamber is above ambient.
The chamber will needed to be temperature controlled below the saturation temperature of the solution, perhaps with an external water bath. The
obvious problem is as the solution becomes dilute the growth rate will reduce but not until the crystal is a signicant fraction of available solute.
The papers explains nucleation theory and give various methods to prevent it.
I would like to make a big sodium thiosulfate crystal. The hexagonal crystal habit would look nice. Its solutions do not readily nucleate so it
should be easy even with mild filtering.
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Dwarvensilver
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Well I could put it up there with my growing list of unfinished projects I suppose  , but I really don't have room for even a 5L set up.
My current crystal room is at work by the grace of my superiors  and I don't
want to push my luck lol.
Sodium thiosulfate hmm, I will look and see if we have some kicking around.
It does not desiccate as easily as sodium sulfate does it, my last attempt at growing one resulted in a great crystal that slumped into powder in a
very short period.
There is nothing more useless than doing well that which need not be done at all.
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Fantasma4500
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as i managed to produce a very large amount of ammonium phosphate the solution now stays hot for much longer, and a trick is to take a saturated
solution that isnt near 100*C but rather just about 60*C, as the initial cooldown will last longer, as the sorrounding atmosphere is closer to the
solution, filled thermocan halfway up and it has now been staying hot for a few days
now im thinking of a very simple way to keep the heat, a styrofoam box, within a styrofoam box, the outer part with hot water, although i still really
dislike having to handle water, but it would also be quite the hassle to load a steel cylinder or brick into an oven and having it heat up over the
course of a day to serve as heating source in outer layer box
now this time i got a pretty big crystal, millimetres bigger and i wouldnt have been able to get it out of the thermocan but it appears to be a mix of
di and triammonium phosphate
1000L flask? "smuv" is your man.
http://www.sciencemadness.org/talk/viewthread.php?tid=24908&...
edit: found polyurethane containers
https://www.tedpella.com/cryo-supplies_html/Cryo-compatible-...
[Edited on 22-10-2016 by Antiswat]
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Fantasma4500
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very long time ago i decided to buy 100 melamine sponges as the chemical compound itself has some potential, it is quite heat resistant and to my
surprise it has a very high r-value, relatively so, what is very interesting about these sponges is that you can use it as building blocks, its very
heat resistant, easy to cut and can yet hold up to some wear
r-value of 5, super cheap over ebay
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Fleaker
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This was a fun thread to read!
I need to do some crystallization work on K2TaF7.
I've been charged with getting large crystals that are easily washed and especially easily dried before crushing and being reduced with sodium to the
metal.
Less occluded moisture means less H & O in the Ta metal--a good thing for my purposes!
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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Fantasma4500
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i found this "gem" at 4m 38s, a sort of sophisticated setup for crystal growing, i really fancy the shape of alum crystals too, and where i live that
is available OTC
https://youtu.be/oz2MlC9pg7c?t=4m38s
i have found it also that a seed crystal can be glued onto a stick or whatever, then be inserted into the solution to be grown, the string i have
keeps untying itself and even breaks after a week of crystallization, it also appears to me that a crystal when glued to something facing downwards in
the solution appears to be growing more downwards than expanding sideways, not sure if this is just a faulty observation or something that happens
only with monoammonium phosphate
K2TaF7 sounds exotic, please do post if you get interesting results
im pondering to add pictures to all wikipedia chemical pages of the respective chemicals in their crystal form, would make wiki pages a little bit
more interesting to walk through
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