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Author: Subject: Best Way to Prevent Crystals from being Stuck to Glass?
LuckyWinner
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[*] posted on 26-11-2020 at 14:14
Best Way to Prevent Crystals from being Stuck to Glass?


Example:
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you made some NaI by reacting Iodine with NaOh.
you boil down the water to get the crystals.
once dried out its like they are glued to the glass.
even with a hammer and chisel... it cant be separated hardly...


My proposed Solution:
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put crystal containing solution inside a plastic container PE or HDPE
inside a vacuum desiccator that leads into a gas washing bottle
which is filled with Calcium Chloride.
desiccator is on mag stir hotplate.

what happens:
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vacuum lowers the BP of water to prevent melting of plastic container.
water vapor gets absorbed by CaCl2 and prevents Vacuum pump from drowning.
flexible plastic container allows for easy discard of crystals.



another solution:
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Teflon backing paper can be used up to 260C...
this lining is inside your pyrex dish that you put inside the oven
with your aqueous crystal mix...




anything better then these 2 methods?
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Heptylene
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[*] posted on 26-11-2020 at 14:24


Have you tried boiling down the water while using magnetic stirring? In my experience this makes slurries of fine crystals which are easy to vacuum filter off.

Or boil the solution until you have a humid powder, then spread it around with a spatula and dry it slowly at progressively higher temperatures. You want to avoid re-dissolution of the powder in the adhering water.
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