This phosphate database has been developed specifically for hydrated magnesium and calcium phosphate cements and is fully compatible with the Cemdata18 database for Portland, calcium aluminate, calcium sulfoaluminate and blended cements. It is available in GEMS program formats, and includes thermodynamic properties determined from various experimental data published in recent years for phosphate containing solids and aqueous complexes.
The phosphate database covers hydrates commonly encountered in hydrated magnesium and calcium phosphate cements in the temperature range 0-100 °C and is compatible with the GEMS default kernel database (GEMS version of PSI/Nagra data base) and the CEMDATA data. Hence, the phosphate files comprise a specific extension to the GEMS kernel data base.
To use the phosphate data base in GEMS-PSI package, please download it to your hard disk and perform the following steps:
- Unzip the downloaded zip file (contains a directory named "phosphate.default") into a temporary directory, e.g. as /Tempfiles/phosphate.default
- Find where you have GEMS installed (on Windows, usually under C:\Users\"your name"\GEMS39\Gems3-app\Resources\DB.default). Under Linux, this may need a root password.
- Copy all files from /Tempfiles/DB.default into the DB.default directory.
Start GEMS and create a new project. In the "Selection of Independent Components..." dialog, turn on "Kernel(Nagra-PSI)" and "phosphate". This will link the Phosphate database files as a specific extension to the kernel Nagra-PSI database.
Delect Independent Components to form the system and click "Ok" to proceed as usual.
Download of the PHREEQC version of the phosphate database
The phosphate data base has developed together with the auxiliary information from the Nagra/PSI-Thermodynamic Data Base. It was converted to PHREEQC-format for temperatures 0-100 °C and focusses on magnesium phosphates. The Phreeqc user should copy the thermodynamic data listed in the phosphate data file into the input of his/her Phreeqc calculation, in order to introduce the phosphate data into the host database in use. The PHREEQC version of the Phosphate Thermodynamic Data Base is available here.
Phosphate 01: Mg2KHP2O8_15H2O removed from solution species and added to solid phases in the PHREEQC and Geochemist's Workbench version.
Thermodynamic data for Mg-phosphate and Ca-phosphate:
Thermodynamic data for magnesium and calcium-phosphate have been collected in Lothenbach et al (2019) and Xu et al (2020)
Lothenbach, B., Xu, B., Winnefeld, F. (2019) Thermodynamic data for magnesium (potassium) phosphates. Applied Geochemistry, 111, 104450.
Xu, B., Lothenbach, B., Winnefeld, F. (2020) Influence of wollastonite on hydration and properties of magnesium potassium phosphate cements, Cement and Concrete Research, 131, 106012