If you want anhydrous sodium carbonate, put it in a sheet pan, in a thin layer,
and dry at 125 °C (or 260 °F) for about 4 hours. If starting with “washing
soda” air dry for a couple of weeks then oven dry to go to the anhydrous form.
It all depends on your local relative humidity. In Northern New Mexico, we do
not have any. HI HI
Howard Efner
73 de KF5RGU
On Mar 14, 2021, at 17:54, Wilbert van den Berg <wilbert@xxxxxxxxxxxxxxx>
wrote:
To go from anhydrous Sodium Carbonate to monohydrate, divide by 0.83 (50 gr
becomes 60 gr). To go from monohydrate to anhydrous, multiply by 0.83 (50 gr
becomes 41.5 gr).
Washing soda is often the decahydrate form of semi-transparant christals.
Monohadrate are non-transparent matte-white christals. To change washing soda
into monohydrate, leave it at the air for two weeks while stirring it daily.
You can speed up the process by placing it in a warm (not hot) oven or by
microwaving it. But you'll never know how much monohydrate and how much
anhydrous you are producing.
Le 14/03/2021 à 22:16, `Richard Knoppow a écrit :
That helps. I was about to post that if the purity includes the hydration it
must be desiccated but evidently not. European formulas, like AGFA/Ansco
formulas usually specified monohydrated carbonate while American formulas
specfied the desiccated form. AGFA said in their literature it was because
the monohydrated is the most stable. I have forgotten the ratio by weight of
the two but it should not be difficult to find.
--
wilbert@xxxxxxxxxxxxxxx
04 73 72 19 20
"Quand on se retrouve du côté de la majorité, il est temps de prendre du
recul et de réfléchir."
Mark Twain
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