Sodium Carbonate problem

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I have 1000g of Sodium Carbonate 10-hydrate, that is crystals with only 40% Sod. Carbonate and 60% water. These crystals forms hard lumbs that are difficult to handle and weigh.

Is it possible to dry the crystals into anhydrous form in the oven? Let's say at 50 degrees Celsius for a day or two?

-- Patric (jenspatric@mail.bip.net), August 28, 2001

Answers

Use enameled pot and stovetop flame. It's a matter of minutes so be very careful. Do not use anything that is not compatible with dishwasher. Aluminum pans are not safe. You can also start this process with baking soda (bicarbonate) which will result in sodium carbonate, CO2 and water. Do these at your own risk.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), August 30, 2001.

I decided to use the carbonate as it is. If I try to take the water out of the crystals, I can't be sure how much water is left when I'm going to weigh the powder. Now I know that I have to use 2,7 times the amount if the recipe says anhydrous carbonate.

Sheesh! Hate the clumping! Next month I will buy 1000g of anhydrous carbonate instead. >:-|

-- Patric (jenspatric@mail.bip.net), August 30, 2001.


You can see when almost all water is given up, and you can feel it because the powder becomes much less stickey. I prefer to "overcook" my carbonate to make sure vast majority of water and possibly absorbed CO2 are given up.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), September 01, 2001.

If you have access to a supplier of swimming pool chemicals, which includes many hardware stores, you can get pHPLUS that is used for raising the pH of pools. It is 98% sodium carbonate, the rest inert. I heated some to see if it would change weight and it did not. I have been using it ever since as anhydrous for my photo grade carbonate. It is about 1/5 the cost of what you would get at a photo store or even Pfotographer's Formulary.

Pat Gainer

-- Patrick A. Gainer (pgainer@rtol.net), September 10, 2001.


great tip Pat...!!!!!

-- Jorge Gasteazoro (jorgegm@worldnet.att.net), September 10, 2001.


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