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Edting database in GWB


Godfrey
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Hi

 

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.

 

Regards

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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.

 

Regards,

 

Brian Farrell

Aqueous Solutions LLC

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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.

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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,

Brian

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