In a message dated 10/6/2001 3:10:35 PM Eastern Daylight Time, [email protected] writes:
> My comment was referring to room temperature. The only reaction I recall at > elevated temperature is that silver carbonate gives up the CO2 to form > silver oxide again. It is this reversable reaction that is used to remove > CO2 from breathable air in space craft. > > Ag2O + CO2 (in the presence of water) --> Ag2CO3 > > Above 220 C the silver carbonate reverts back to CO2 and Ag2O. > > Other than that, silver oxide is stable. > > frank key > Frank: You have to describe the system and temperature before you can define the stability of Ag2O . Is your system Ag2O in air (where the partial pressure of CO2 is 3.55 * 10-^4 atm, or is the Ag2O in 1 atmosphere of CO2, or somewhere in between? It makes quite a difference. In the clay firing scenario, there is a question as to the correct CO2 partial pressure since an excess of fuel may be used plus the ever present CO2 combustion product itself. Suffice it to say that it is difficult, and probably impossible, to predict with any degree of certainty, what form of silver will be present. Under such circumstances operational repeatability must be demonstrated first before an empirical assessment (probably the only practical option) can be used. In any case, I would be surprised if silver oxide, and not silver metal were found in any quantity. Roger
