Jump to content
Geochemist's Workbench Support Forum

Edting database in GWB


Recommended Posts



I am trying to edit thermo database to include ettringite mineral. When I want to use for ACT2 it is giving an error; unknown reaction "OH-". If I click ok it go on to say Last line read is line 3889: 2.000 Al+++ 12.000 OH-. If I click ok again it says ACT2 stop: bad thermo database ACT2 ending. what could be problem and how can I rectify it.



Link to comment
Share on other sites

Hello Godfrey,


Without seeing your thermo dataset I can't say for sure, but I imagine the problem is in the way you've balanced the reaction. The Basis species (and Redox species) are the building blocks used to form all other aqueous species, minerals and gases. It looks like you're using OH- as one of the species that react to form ettringite, but this is most likely not one of the Basis species in your thermo dataset. I think if you use H2O and H+ instead you'll be fine.


If that doesn't fix your problem you can post your thermo dataset here and I'd be happy to take a look.




Brian Farrell

Aqueous Solutions LLC

Link to comment
Share on other sites

Hi Brian


I have managed to edit and save the mineral in the database now. The problem now is that the mineral (ettringite) is not being picked by the Act2 program when I want draw stability diagrams for Al and sulphate containing minerals. Please find attached the edited database.

Link to comment
Share on other sites

Hi Godfrey,


I took a look at your dataset and it works with Act2. Perhaps you didn't include all of the components necessary to form Ettringite? These are the basis species in the reaction for Ettringite that you added to the dataset: H2O, SO4--, Al+++, H+, and Ca++. Since you mentioned you're interested in aluminum and sulfate containing minerals, perhaps you forgot to include Ca++ (either as an axis or under the "in the presence of" field).


Hope this helps,


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...