RE: Completion of PhreeqcI

["David L Parkhurst" <dlpark@xxxxxxxx>]

> 1)  In example 9 the oxidation of Fe(II), could not the decoupling of
Fe(III) and Fe (II) be more simply done by removing the Fe(III) to Fe(II)
relationship instead of redefining variables.

Perhaps if I had been more clever at the time of development, but no, the
only way is to rewrite the database so that Fe(2) and Fe(3) are not part of
the same "element".


> 2)  This is actually my main question.  I am interested in exploring the
role of the solid phases during kinetic reaction.  Again using example 9,
as
the reaction progresses, the solution very quickly becomes super saturated
with goethite.  Is there some way of using basic to get the goethite to
precipitate out as the SI is reached.  Sort of IF SI > 0 THEN goethite
precips.  Setting the system in equilibration with goethite does not really
work because it will force this to happen, very early in the evolution of
the reaction before enough Fe(III) is produced.

If you define goethite in EQUILIBRIUM_PHASES, but give it 0.0 moles, then
it can not dissolve. It will precipitate when supersaturated. However, once
it has precipitated, it can redissolve. There is no way to force goethite
only to precipitate and never to dissolve. I have added a capability to
dissolve only (EQUILIBRIUM_PHASES), and I should have included precipitate
only, but have not.

David


David Parkhurst (dlpark@xxxxxxxx)
U.S. Geological Survey
Box 25046, MS 413
Denver Federal Center
Denver, CO 80225


                                                                                                                             
                      "David T. Long"                                                                                        
                      <long@xxxxxxx>           To:      "David L Parkhurst" <dlpark@xxxxxxxx>                                
                                               cc:                                                                           
In-Reply-To: <NBBBLADMFKOPNKDAADIDAEPJDFAA.long@xxxxxxx>
                      10/24/01 10:50           Subject: RE: Completion of PhreeqcI                                           
                      AM                                                                                                     
                                                                                                                             
                                                                                                                             



Hi Dave,

The new window version of PhreeqcI is fantastic.  I have used the older
version, but this is a significant step up.  Great work from you and your
team.

So I have two questions, I know you are busy, but if you can help with

1)  In example 9 the oxidation of Fe(II), could not the decoupling of
Fe(III) and Fe (II) be more simply done by removing the Fe(III) to Fe(II)
relationship instead of redefining variables.

2)  This is actually my main question.  I am interested in exploring the
role of the solid phases during kinetic reaction.  Again using example 9,
as
the reaction progresses, the solution very quickly becomes super saturated
with goethite.  Is there some way of using basic to get the goethite to
precipitate out as the SI is reached.  Sort of IF SI > 0 THEN goethite
precips.  Setting the system in equilibration with goethite does not really
work because it will force this to happen, very early in the evolution of
the reaction before enough Fe(III) is produced.

Any thoughts would be appreciated.

dave



____________________________________
David T. Long
Professor
Aqueous & Environmental Geochemistry
Department of Geological Sciences
206 Natural Science Building
Michigan State University
East Lansing, MI 48824-1115
1.517.353.9618 phone
1.517.353.8787 fax
long@xxxxxxx
http://www.cevl.msu.edu/~long

-----Original Message-----
From: David L Parkhurst [mailto:dlpark@xxxxxxxx]
Sent: Thursday, October 18, 2001 6:22 PM
To: phreeqc_list@xxxxxxxxxxxxxxxxxxxxxx
In-Reply-To: <NBBBLADMFKOPNKDAADIDAEPJDFAA.long@xxxxxxx>
Subject: Completion of PhreeqcI


Release of:
     PhreeqcI RC1 (Release Candidate 1, Interactive version)
     PHREEQC Version 2.5 (Batch version)
     Database llnl.dat 1.11
Status:
     PHAST 0.3

PhreeqcI RC1 (Interactive version):

PhreeqcI is now complete and available for final testing. All design
features have been implemented and screen-driven input for all keyword data
blocks is available. PhreeqcI RC1 is based on PHREEQC version 2.5. This
version of PhreeqcI is expected to be the last version before the official
release of the program.

PHREEQC Version 2.5 (Batch version):

This release includes only minor additions and bug fixes relative to
version 2.4.2. A feature has been added to allow elements to be defined
using brackets ("[]"). Any characters, including numbers, within the
brackets are treated as the element name. This was introduced to simplify
expansion of the model to isotopic species. [13C], [14C], and [18O] are
legal element names. Several bugs have been fixed in the code, for more
information see RELEASE.TXT in distribution or the status page at
https://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc.  Current versions
for Windows, Linux, and Solaris are now available at
https://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc and will soon be
added to http://water.usgs.gov/software.

Database llnl.dat (version 1.11):

Sign errors in log K were fixed for redox reactions for some rare earth
elements (REE).  Some redundant REE species were removed, generally ReeO2-
was retained and Ree(OH)4- was removed.

PHAST 0.3:

The current beta test version of PHAST is 0.3. There have not been any
reported bugs for this version. No additional features are planned before
release of the program.

BUGS:

Report to dlpark@xxxxxxxxx

David Parkhurst (dlpark@xxxxxxxx)
U.S. Geological Survey
Box 25046, MS 413
Denver Federal Center
Denver, CO 80225