David, The radium01.txt runs (converge in that sense), just give gabage results. I did remove the knobs data block. -Chen --- David L Parkhurst <dlpark@xxxxxxxx> wrote: > > > > I have run into a couple of non-convergence with > phreeqc lately. I have attached 3 input files. The > file radium01.txt attempts to simulate solid > solution > formation (Ra,Ba)SO4 in a reactive transport regime. > I > have tested the same solid solution model without > transport, and it ran fine. When there is transport, > it does not converge, and also, it simply gives > equal > mole fraction of the two end-members. Additionally, > I > suspect that the equilibrium sulfate and barium > concentrations are shifted a little, that is, the > product or IAP is right but the relative activities > of > sulfate and barium are shifted. > > If you remove the KNOBS data block, the file runs. > If there is still a > problem with the mole fractions, let me know. > > > The file kinetics qrtz2.txt attempts to simulate > reactive transport when quartz kinetics is involved. > It does not converge. The kinetics01alb.txt for > albite > dissolution converged. So does a similar file for > K-feldspar. However, when I have both albite and > k-feldspar kinetics, it did not converge. > > I'm not sure what you are trying to do here. With > the number of minerals in > EQUILIBRIUM_PHASES, the activity of H4SiO4 is > probably nearly invariant. I > ran a little test adding a millimole of SiO2 and > the solution composition > barely changed. Adding kinetics of quartz to this > system may not make much > sense. I'm not sure if albite/k-spar is related or a > different problem. > > > > Separately, I am going to attend GSA in Denver. If > you > are still interested in conducting a short course > next > year, I can come in early or stay late for > discussions. I have taught a geochemical modeling > course for a semester and you probably have some > teaching materials too. I don't think it will take > that much time to prepare the short-course. > > I think I really do not want to teach a short course > at GSA. There are too > many other things I'd rather do and time is always > at a premium. > > David > > > David Parkhurst (dlpark@xxxxxxxx) > U.S. Geological Survey > Box 25046, MS 413 > Denver Federal Center > Denver, CO 80225 > > Project web page: > https://wwwbrr.cr.usgs.gov/projects/GWC_coupled > > > __________________________________________________ Do You Yahoo!? Yahoo! Finance - Get real-time stock quotes http://finance.yahoo.com
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 2191 since Jan 22, 1998.