> 1) When I entered the seawater chemical analysis of NORDSTROM into the PHREEQC-2.7, the obtained results ? ex. Saturation indices - were different from those described in the pdf-Example-1 (without U). I don't understand what is different. Looking in the manual, the saturation indices, calcite .76 and gypsum -.63 for example, are the same as your spreadsheet. > 2) When I checked the molal concentration of the mineral species, it was found that the minor Fe, Mn & Si minerals are given in higher amounts. I don't know, may my simple calculations are wrong. There is no information about molal concentrations of minerals in PHREEQC speciation calculations. The saturation index can not be converted into an amount of mineral. The saturation index simply states the thermodynamic state of the water relative to a mineral. It indicates whether a mineral should dissolve (SI < 0) or precipitate (SI > 0). SI near zero may mean that a mineral is reacting sufficiently fast to maintain equilibrium, or it may be a coincidence. You need to consider the mineralogy of your system and the kinetics of mineral formation and precipitation. > 3) I tried to correlate the obtained PHREEQC-2.7 data with the classical simplified "Probable Salt Combination Model" but the difference still very big. Attached herewith my calculation sheet. I don't know the probable salt method, but it looks like it distributes the solutes among a series of salts. There is nothing in PHREEQC that corresponds with this calculation. 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 "Dr. Samir El-Manharawy" To: "David L Parkhurst" <dlpark@xxxxxxxx> <geo230@xxxxxxxx> cc: Subject: PHREEQC-2.7 03/14/03 12:45 AM Please respond to "Dr. Samir El-Manharawy" Dear Prof. Dr. David Parkhurst U.S. Geological Survey, Denver, Colorado. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> Once more I ask your kind help to understand the comprehensive PHREEQC-2.7 program. Let me tell you first that I am not well familiar with your modern higher kinetics, but I promise to follow your instructions. I noticed the following points: 1) When I entered the seawater chemical analysis of NORDSTROM into the PHREEQC-2.7, the obtained results ? ex. Saturation indices - were different from those described in the pdf-Example-1 (without U). 2) When I checked the molal concentration of the mineral species, it was found that the minor Fe, Mn & Si minerals are given in higher amounts. I don't know, may my simple calculations are wrong. 3) I tried to correlate the obtained PHREEQC-2.7 data with the classical simplified "Probable Salt Combination Model" but the difference still very big. Attached herewith my calculation sheet. I am sure that you are so busy, and not expect an early reply. Best regards, Samir El-Manharawy (See attached file: SW_NORDSTROM-PHRQ1.XLS)
Attachment:
SW_NORDSTROM-PHRQ1.XLS
Description: application/msexcel
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:
https://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/mail/msg00582.html
Email:dlpark@usgs.gov
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number [an error occurred while processing this directive] since Jan 22, 1998.