<HTML>Hi Anthony and sandy,
Please excuse any of the following that seems bizzare... but I'm going to try to work thru my present confusion.
Is it accurate to redefine the issue being pursued here as "What would it take to create the zeolite ZK20 on the surface of existing limestone?" This question naturally follows the assumption that the existing limestone CANNOT have ZK20 within it if it is indeed natural limestone AND if it is true that ZK20 is NEVER found in natural limestone (assumptions which I hope we can address individually elsewhere rather than as part of this effort).
It would seem to me that what we have to focus on initially is that the chemical elements contained in the ammonium (NH4+) and the natron (see other post for complicated contents of Egyptian natron) have to be able to supply ample alumino-silicate content to act as the main ingredient so to say for the zeolite (and only the natron contains any Aluminum or Silicon in the form of 2.9% "Clayish and siliceous sand"... kaolin clay has existing alumino-silicates and sand is basically silicon oxide). Just recognizing that the chemical formula for common feldspars is XAl(1-2) Si(3-2) O8 (with the number of Aluminums and the number of Silicons depending upon whether the unknown X happens to be a +1 element like sodium (Na+) or potassium (K+) or a +2 element like calcium (Ca++)), one can see that what must be the binder or zeolite portion of the formula is the alumino-silicate part (hence, one type of feldspar is K(AlSi3O8), while another would be Ca(Al2Si2O8).
In other words, until we find someone who can tell us whether the small percentage of alumino-silicate that might come from the clay in the natron itself is enough to constitute the source of the necessary alumino-silicate for producing the zeolite binder, or whether the limestone has any available kaolinitic percentage (another source of alumino-silicates), we will not be able to know whether the presence of ammonium matters. Without sufficient alumino-silicate present from some source, it is my understanding that the zeolite ZK20 is not possible. If we can determine with certainty that sufficient alumino-silicate is present from some source (either kaolinitic limestone or the natron itself), only then would we then pursue the question of how reactive that alumino-silicate would be in the presence of the ammonium.
Any takers on any of the above problems/questions?
Litz</HTML>
