Brian,
I am interested in writing some custom rate laws into a script for dissolution of some minerals. I have an idea as to how to do this but I think I am possibly missing something critical. Below is a rate law for anorthite dissolution that is one of the simpler expressions I am interested in incorporating into a React model. It has the form:
Rate = k+[((aH+3n/aAl3+n)Keq)/(1+Keq(aH+3n/aAl3+n))]
where n = 1/3, Keq is a known constant, and k+ is the forward rate constant. "a" represents activities and the parameters with n in them are exponents on the various hydrogen ion and aluminum ion activities. I have attached a file with a better representation of the expression. Also, I have not included the surface area of the (1-Q/K) terms because those are obvious to me as to their implementation. Any suggestions you have would be greatly appreciated.
Best wishes,
Karen J.
Anorthite Rate Law.pdf