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 =============================
Please note that some U.S. Geological Survey (USGS) information accessed through this page may be preliminary in nature and presented prior to final review and approval by the Director of the USGS. This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the sole responsibility of the user.
Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.
The URL of this page is:
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number 3827 since Jan 22, 1998.