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Re: Pyrite oxidation rate law



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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