Sciencemadness Discussion Board

Calcium Sulfate as a desiccant - Will anhydrous work?

RogueRose - 21-6-2016 at 11:33

Wiki states that Anhydrous CaSO4 is very slow to react with water, almost to the point of not absorbing or mixing. It does state there is another form of anhydrous, γ-Anhydrite .05H2O, which will react with water and is mentioned as a commercial desiccant.

The difference in temp between the two anhydrites is 180C and 250C as stated by Wiki. I've found a lot of compounds are very slow to decompose at their stated temp and was wondering if anyone has ever used the pure anhydrous as a desiccant.

Sulaiman - 21-6-2016 at 15:29

rock-growing in RBFs seems to be not a popular pastime :D

NEMO-Chemistry - 21-6-2016 at 15:45

AFAIK Calcium sulphate is also known as plaster of paris

Scalebar - 21-6-2016 at 23:37

We used to use it to remove the water during meat analysis - the pulped sample would be mixed with Pet. Ether and a good dollop of anhydrous calcium sulphate and shaken. The ether was then analysed for fat content. This was thirty years ago though...

NEMO-Chemistry - 22-6-2016 at 01:50

Quote: Originally posted by Scalebar  
We used to use it to remove the water during meat analysis - the pulped sample would be mixed with Pet. Ether and a good dollop of anhydrous calcium sulphate and shaken. The ether was then analysed for fat content. This was thirty years ago though...


IDKW, but that has just put me off Kebabs!