pyro6314
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Help - DIY Indicating Dessicant
I was planning on purifying Ca2SO4 from old drywall then drying it in the oven to get the anhydrous form.
As for the indicating part, anyone have a synth for Cobalt Chloride? Or anyone know where I could easily find Cobalt metal or a Cobalt donor?
Thanks
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UnintentionalChaos
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You can get cobalt sulfate (I think someone mentioned this one), cobalt oxide, or cobalt carbonate through a ceramics supplier as glaze colorants.
Plaster of paris is fairly pure CaSO4 and for how cheap it is, it will be a lot less work than cleaning up drywall
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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not_important
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Correct, use plaster of Paris, buy it in larger amounts.
And your best bets for getting cobalt are as UC said, pottery supply houses or as a poor alternative Alnico magnets - usually 8-12% Al, 15-26% Ni,
5-24% Co, up to 6% Cu, up to 1% Ti, the remainder is Fe.
Make sure you don't overheat CaSO4, or it will go "dead burnt" and not absorb water very well.
| Quote: | TECHNICAL DATA - REGENERATION OF DRIERITE DESICCANTS
After normal use, any of the forms of DRIERITE may be regenerated for reuse. The operation is simple and involves only standard equipment. The used
and exhausted desiccant should be ventilated to remove vapors, if any, and stored in a convenient container until a sufficient amount is accumulated
to justify the work of regeneration.
Regular and Indicating DRIERITE
For the regeneration of Indicating DRIERITE and small lots of Regular DRIERITE , the granules may be spread in layers one granule deep and heated for
1 hour at 210 C or 425 F. The regenerated material should be placed in the the original glass or metal container and sealed while hot. The color of
the Indicating DRIERITE may become less distinct on successive regenerations due to the migration of the indicator into the interior of the granule
and sublimation of the indicator.
Commercial Grade and Du-Cal DRIERITE
Exhausted Commercial DRIERITE or Du-Cal DRIERITE should be spread about 1 inch deep in shallow pans and heated in a oven at 450 F or 230 C for 2 hours
to achieve complete dehydration. The regenerated material should be placed in the original container and sealed while hot.
The Importance of Temperature
The temperature at which DRIERITE desiccants are regenerated is crucial in restoring DRIERITE to its original condition. Absorbed moisture is water of
hydration and is chemically bound to the calcium sulfate of DRIERITE. Temperatures in the range of 400- 450F are required to break these bonds and
release absorbed moisture. Lower temperatures, regardless of heating time, will not regenerate DRIERITE unless applied under vacuum (26" Hg, 325F or
28" Hg, 275F). Care should be taken not to overheat DRIERITE Desiccants. High temperatures can alter the crystal structure and render the desiccants
permanently inactive. |
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pyro6314
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K thanks guys. I will do some shopping to see what I can find. Hopefully I can come up with something.
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