Here's Tony's reply from last year. David David Parkhurst (dlpark@xxxxxxxx) U.S. Geological Survey Box 25046, MS 413 Denver Federal Center Denver, CO 80225 ----- Forwarded by David L Parkhurst/WRD/USGS/DOI on 03/05/01 11:24 AM ----- Tony Appelo <appt@xxxxxxxxx> To: mwilliamson@xxxxxxxxxx cc: dlpark@xxxxxxxx In-Reply-To: <B6C92803.30F%mwilliamson@xxxxxxxxxx> 01/24/00 11:59 Subject: Re: Pyrite oxidation rate law AM At 02:47 PM 1/21/00 -0800, you wrote: >While reading through the PHREEQC manual, I noted the reference to the rate >law for pyrite oxidation (by DO) that Don Rimstidt and I published. The >form is seems correct, but the rate constant is written as 10^-10.19 (log k >= -10.19), as compared to our published value of 10^-8.19 (log k = -8.19). >Am I missing something here? My concern centers on whether or not other >rate expressions that I have been using (in PHREEQC) are in an incorrect >format for the program. Dear Mark, Thanks for giving attention to the rate laws in the PHREEQC-2 database. The constant was adapted to comply with units of mol/dm3/s, whereas you have defined the constant in mol/m2/s in your GCA paper. In general in PHREEQC-2, the units have to give mol/s. The volume defaults to 1 kg = 1 dm3, but can be adjusted with the identifier -water in keyword SOLUTION. Hope this helps you out, with kind regards, Tony. ============================= Dr C.A.J. Appelo Valeriusstraat 11 1071 MB Amsterdam, NL tel. ++ 31 20 6716366 e-mail appt@xxxxxxxxx website http://www.xs4all.nl/~appt/index.html =============================
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