iandol on wed 23 may 01
People who are trying to use a saturated solution of Sodium =
Carbonate,aka soda ash, will need to keep the solution hot. Sodium =
Carbonate has a complex relationship with water and forms many hydrated =
salts, that is, salts with water of crystallisation. To approximately =
30% anhydrous soda ash content it is possible contain the salt in =
solution above 37 Celsius. Adding more solid will precipitate the =
monohydrate, even up to boiling point. As the temperature declines, =
concentrations below 30% tend to precipitate the Deca-hydrate, more =
usually known as Washing soda.
Please refer to the Na2CO3 - H2O phase transformation diagram to =
appreciate the complex relationships of these compounds.
Ivor Lewis. Redhill, South Australia.