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Hi to all I`m a european researcher and I`m at Indiana University in USA, so I need a help to use gwb standard, this is the first time that i use it and I`ve to make activity diagrams about some minerals and a fluid.

 

Please can you help me?

 

I don`t know which module i have to use, I think Act2 but I don`t know.

 

Many thanks

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Hi to all I`m a european researcher and I`m at Indiana University in USA, so I need a help to use gwb standard, this is the first time that i use it and I`ve to make activity diagrams about some minerals and a fluid.

 

Please can you help me?

 

I don`t know which module i have to use, I think Act2 but I don`t know.

 

Many thanks

 

Hello:

 

Act2 is indeed the module that you'll want to use for constructing solubility diagrams. The best place to start is the "Using Act2" chapter on page 34 of the GWB Essentials Guide (version 7). Section 3.3 on solubility diagrams (page 39) will prove especially helpful.

 

Let me know if you have any further questions.

 

Best regards,

 

Tom Meuzelaar

RockWare, Inc.

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Hello:

 

Act2 is indeed the module that you'll want to use for constructing solubility diagrams. The best place to start is the "Using Act2" chapter on page 34 of the GWB Essentials Guide (version 7). Section 3.3 on solubility diagrams (page 39) will prove especially helpful.

 

Let me know if you have any further questions.

 

Best regards,

 

Tom Meuzelaar

RockWare, Inc.

 

Hi thanks for your help, at first I have version 6 of gwb, and I try to explain what I have to do.

 

I` have to do activity diagrams for 5 mineral phases, for this reason I need activity coefficient for these phases, i read tha I can use RXN to calculate activity coefficient, but there aren`t my minerals in rxn, how I can insert them?

 

thanks for your help

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Hi thanks for your help, at first I have version 6 of gwb, and I try to explain what I have to do.

 

I` have to do activity diagrams for 5 mineral phases, for this reason I need activity coefficient for these phases, i read tha I can use RXN to calculate activity coefficient, but there aren`t my minerals in rxn, how I can insert them?

 

thanks for your help

 

You can use either SpecE8 or React to calculate activity coefficients for dissolved species. If you want to define a system in equilibrium with a mineral phase, simply swap that mineral phase in for one of the Basis components for which its formation reaction is written in the thermodynamic database.

 

For general examples of this refer to the Equilibrium Models section on p. 48 of the GWB Essentials Guide (version 6). Mineral swapping is covered on page 50.

 

I hope this helps,

 

Tom Meuzelaar

RockWare, Inc.

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I think that I`m having too many problems. Let me start again from beginning.

 

I have 3 mineral phases (Analcime, Phillipsite and Chabazite).

 

I inserted Phillipsite and Chabazite in database.

 

I have to describe which is the stability of those mineral phases (in only one diagram) with 4 different Temperature 110 deg C (120 - 130 - 140) at the same pressure.

 

I have only chemical composition of all minerals.

 

first question: I need other chemical datas?

 

my diagram would be: x axis: log ((aK+)^2/aCa2+) : y axis: log ((aNa+)2/aCa2+)

 

please can you give me some instructions?

 

Thanks for any help You can give me.

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I think that I`m having too many problems. Let me start again from beginning.

 

I have 3 mineral phases (Analcime, Phillipsite and Chabazite).

 

I inserted Phillipsite and Chabazite in database.

 

I have to describe which is the stability of those mineral phases (in only one diagram) with 4 different Temperature 110 deg C (120 - 130 - 140) at the same pressure.

 

I have only chemical composition of all minerals.

 

first question: I need other chemical datas?

 

my diagram would be: x axis: log ((aK+)^2/aCa2+) : y axis: log ((aNa+)2/aCa2+)

 

please can you give me some instructions?

 

Thanks for any help You can give me.

 

Hello:

 

I can take a quick look to point you in the right direction. Can you send me your modified thermo database?

 

Regards,

 

Tom Meuzelaar

RockWare, Inc.

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Hello:

 

I can take a quick look to point you in the right direction. Can you send me your modified thermo database?

 

Regards,

 

Tom Meuzelaar

RockWare, Inc.

 

this my modified themro database

 

thank you

thermo_mod2.txt

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this my modified themro database

 

thank you

 

Hi:

 

You'll want to start by re-writing the reactions for Chabazite and Phillipsite in the modified database. These reactions cannot be processed by Act2 because they are not written in terms of the thermo database Basis species.

 

As an example, you might choose to write the reaction for Chabazite as:

 

CaAl2Si4O12 - 6H2O + 8H+ = Ca++ + 2Al+++ + 4SiO2(aq) + 10 H2O

 

You'll need to modify the log K data to fit the reaction and be sure to carry out your mole weight to 4 decimal points so that GWB does not flag an error when it opens the database.

 

For more information about modifying the thermodynamic database, refer to the Appendix called Thermo Datasets at the end of the GWB v6 Reference Manual.

 

To understand the concept of Basis species, and the motivation for having a basis in thermodynamic datasets, refer to Chapter 3 of Craig Bethke's book Geochemical and Biogeochemical Reaction Modeling.

 

I hope that helps,

 

Tom Meuzelaar

RockWare, Inc.

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Hi:

 

You'll want to start by re-writing the reactions for Chabazite and Phillipsite in the modified database. These reactions cannot be processed by Act2 because they are not written in terms of the thermo database Basis species.

 

As an example, you might choose to write the reaction for Chabazite as:

 

CaAl2Si4O12 - 6H2O + 8H+ = Ca++ + 2Al+++ + 4SiO2(aq) + 10 H2O

 

You'll need to modify the log K data to fit the reaction and be sure to carry out your mole weight to 4 decimal points so that GWB does not flag an error when it opens the database.

 

For more information about modifying the thermodynamic database, refer to the Appendix called Thermo Datasets at the end of the GWB v6 Reference Manual.

 

To understand the concept of Basis species, and the motivation for having a basis in thermodynamic datasets, refer to Chapter 3 of Craig Bethke's book Geochemical and Biogeochemical Reaction Modeling.

 

I hope that helps,

 

Tom Meuzelaar

RockWare, Inc.

 

hi, I`m still having problems with the database, this my modified database

 

Chabazite type= silica

formula= Ca2Al2Si4O12:6H2O

mole vol.= 200.202 cc mole wt.= 416.4200 g

6 species in reaction

11.000 H2O 1.000 Ca++ 2.000 Al+++

4.000 SiO2(aq) -11.000 H+ -1.000 OH-

-3.3630 -3.0810 -2.7573 -2.4617

-2.1708 -1.9414 -1.7559 -1.6027

 

but when I charge it don`t works.

can you suggets any corrections?

 

I want to buy this software for my university but I need absolutely to make it work.

 

thank you for your help

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hi, I`m still having problems with the database, this my modified database

 

Chabazite type= silica

formula= Ca2Al2Si4O12:6H2O

mole vol.= 200.202 cc mole wt.= 416.4200 g

6 species in reaction

11.000 H2O 1.000 Ca++ 2.000 Al+++

4.000 SiO2(aq) -11.000 H+ -1.000 OH-

-3.3630 -3.0810 -2.7573 -2.4617

-2.1708 -1.9414 -1.7559 -1.6027

 

but when I charge it don`t works.

can you suggets any corrections?

 

I want to buy this software for my university but I need absolutely to make it work.

 

thank you for your help

 

Hello:

 

Can you attach the actual modified database so I can take a look at it?

 

Regards,

 

Tom Meuzelaar

RockWare, Inc.

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Hello:

 

Can you attach the actual modified database so I can take a look at it?

 

Regards,

 

Tom Meuzelaar

RockWare, Inc.

 

thank you and please If you can guide me step by step

Thermo_mod2_2.zip

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thank you and please If you can guide me step by step

 

Hi:

 

Have a look at the revised thermo database and compare to your earlier version. There were a number of issues with the original entries for Chabazite and Phillipsite, including:

 

  • chemical reactions were unbalanced (both entries were missing the H+ component)
  • molecular weights did not reflect the mineral dissolution equation
  • one of the components used to balance the equations was not a database basis species (Al2O3)
  • be sure to set the '# of species in reaction' modifier
  • be sure that all numbers are carried out to 4 significant units (use appending zeroes if necessary)

 

The equation I used for balancing Phillipsite is as follows:

 

K3Al3Si5O16-6H2O + 12H+ -> 3K+ + 3Al+++ + 5SiO2 + 12H2O

 

You'll still need to verify that the log K values reflect the actual equations used in the database, or your modeling results will be erroneous.

 

I hope that helps,

 

Tom Meuzelaar

RockWare, Inc.

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Hi, I`m trying to work but I need to insert other three phases, I`m calculating logK but I don`t understand reactions, can you help me?

 

I`m sending a file in which I put your chabazite (working) and my other three phases.

 

Thank you

adding_3_phases.zip

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Hi, I`m trying to work but I need to insert other three phases, I`m calculating logK but I don`t understand reactions, can you help me?

 

Hello:

 

I'll walk you through the steps for Erianite, so that you can do this yourself in the future. Stilbite and Laumontite are already in the extended version of the LLNL database: thermo.dat.v8.r6+.dat.

 

First, note that there are many other discussions in this forum, in Craig's book, and elsewhere about the dangers of adding thermodynamic data from separate sources, or derived by variable methods, to a thermodynamic database. The LLNL database (thermo.dat) is widely considered to be the most internally consistent and reliable thermodynamic database for general use - add data at your own risk.

 

Here's one way to add Erianite (K4Al4Si14O36:15H2O) to the database:

 

Step 1: determine the number of basis components involved in the reaction

 

Components in the "basis species" section (and sometimes "redox couples") of the database are used to construct the reactions for minerals, aqueous species and gases. Since Erionite has K, Al, Si, O and H2O, we'll need the following components: H2O, K+, SiO2(aq), Al+++ and probably H+ for charge balance.

 

basis.gif

 

Step 2: write the reaction for primary components, then balance with H2O, H+... (be sure to balance for charge)

 

Start with arranging the minimum required components:

 

K4Al4Si14O36:15H2O -> 4K+ + 4Al+++ + 14SiO2(aq) + H2O

 

Excess positive charge on the reactant side is balanced with H+ on the product side:

 

K4Al4Si14O36:15H2O + 16H+ -> 4K+ + 4Al+++ + 14SiO2(aq) + H2O

 

Adding up oxygen and hydrogens on both sides leads to the final stoichiometric coefficient in front of H2O:

 

K4Al4Si14O36:15H2O + 16H+ -> 4K+ + 4Al+++ + 14SiO2(aq) + 23H2O

 

There are 5 basis species in this reaction.

 

IMPORTANT: before you start modifying the database, give it a new name, so you don't corrupt the default databases. In case you corrupt a database, don't worry, you can download original copies here.

 

 

Step 3: find a reaction in the database with the same number of species in reaction, make a copy, and change the parameters to fit the new mineral (or aqueous species/gas). Be sure molecular weight is carried to 4 decimals (calculate based on mole weights given in the 'elements' or 'basis species' sections in the database). Basis components on the reactant side are negative.

 

mineral_reaction.gif

 

Step 4: change the log K values to fit the reaction. Note the log K values here still reflect the values copied from the mineral listed below the Erianite entry (Chinochl-14A).

 

 

Step 5: increment the number of minerals (or aqueous species/gases) in the header section by the number of minerals you have added to the database.

 

mineral_increment.gif

 

If you've done this correctly, the database will load without error. I've attached a modified copy of thermo.dat with the Erianite entry.

 

 

Regards,

 

Tom

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Hello:

 

I'll walk you through the steps for Erianite, so that you can do this yourself in the future. Stilbite and Laumontite are already in the extended version of the LLNL database: thermo.dat.v8.r6+.dat.

 

First, note that there are many other discussions in this forum, in Craig's book, and elsewhere about the dangers of adding thermodynamic data from separate sources, or derived by variable methods, to a thermodynamic database. The LLNL database (thermo.dat) is widely considered to be the most internally consistent and reliable thermodynamic database for general use - add data at your own risk.

 

Here's one way to add Erianite (K4Al4Si14O36:15H2O) to the database:

 

Step 1: determine the number of basis components involved in the reaction

 

Components in the "basis species" section (and sometimes "redox couples") of the database are used to construct the reactions for minerals, aqueous species and gases. Since Erionite has K, Al, Si, O and H2O, we'll need the following components: H2O, K+, SiO2(aq), Al+++ and probably H+ for charge balance.

 

basis.gif

 

Step 2: write the reaction for primary components, then balance with H2O, H+... (be sure to balance for charge)

 

Start with arranging the minimum required components:

 

K4Al4Si14O36:15H2O -> 4K+ + 4Al+++ + 14SiO2(aq) + H2O

 

Excess positive charge on the reactant side is balanced with H+ on the product side:

 

K4Al4Si14O36:15H2O + 16H+ -> 4K+ + 4Al+++ + 14SiO2(aq) + H2O

 

Adding up oxygen and hydrogens on both sides leads to the final stoichiometric coefficient in front of H2O:

 

K4Al4Si14O36:15H2O + 16H+ -> 4K+ + 4Al+++ + 14SiO2(aq) + 23H2O

 

There are 5 basis species in this reaction.

 

IMPORTANT: before you start modifying the database, give it a new name, so you don't corrupt the default databases. In case you corrupt a database, don't worry, you can download original copies here.

 

 

Step 3: find a reaction in the database with the same number of species in reaction, make a copy, and change the parameters to fit the new mineral (or aqueous species/gas). Be sure molecular weight is carried to 4 decimals (calculate based on mole weights given in the 'elements' or 'basis species' sections in the database). Basis components on the reactant side are negative.

 

mineral_reaction.gif

 

Step 4: change the log K values to fit the reaction. Note the log K values here still reflect the values copied from the mineral listed below the Erianite entry (Chinochl-14A).

 

 

Step 5: increment the number of minerals (or aqueous species/gases) in the header section by the number of minerals you have added to the database.

 

mineral_increment.gif

 

If you've done this correctly, the database will load without error. I've attached a modified copy of thermo.dat with the Erianite entry.

 

 

Regards,

 

Tom

 

hi, i swapped quartz for SiO2 but I need a higher silica activity, how i can make It?

 

considering Amourfous for SiO2 would be great for me, but Can you explain me how to set the silica activity value (10 or higher for example)?

 

thank you

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hi, i swapped quartz for SiO2 but I need a higher silica activity, how i can make It?

 

considering Amourfous for SiO2 would be great for me, but Can you explain me how to set the silica activity value (10 or higher for example)?

 

thank you

 

Hello:

 

You can set silica activity as follows:

 

silica_activity.jpg

 

If you want to model Amorphous Silica precipitation, you'll either want to create a kinetic model, or simply suppress the more stable silica polymorphs (Quartz, Tridymite, Chalcedony, Cristobalite) using the Config - Suppress option.

 

I hope that helps,

 

Tom

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Hi Tom, I'm still working on my datas and i need another help.

 

I would try to modelling my phases with a particular carbonatic water and I have chemical analysis of this water what can I do?

 

this is my analysis:

 

T °C 15,0

pH 7,0

CE us/cm 524,0

TDS ppm 346,4

CO2 ppm 15,2

H2S+S ppm 0,5

SiO2 ppm 31,2

Na ppm 19,3

K ppm 10,6

Li ppm 0,0

NH4 ppm 0,0

Ca ppm 67,4

Mg ppm 18,0

Sr ppm 0,2

Cl ppm 33,9

SO4 ppm 21,8

HCO3 ppm 269,9

 

How can I insert it in my system?

 

I have to modify the database for H2O?

 

please guide me step by step

 

thank you for your time

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Hi Tom, I'm still working on my datas and i need another help.

 

I would try to modelling my phases with a particular carbonatic water and I have chemical analysis of this water what can I do?

 

this is my analysis:

 

T °C 15,0

pH 7,0

CE us/cm 524,0

TDS ppm 346,4

CO2 ppm 15,2

H2S+S ppm 0,5

SiO2 ppm 31,2

Na ppm 19,3

K ppm 10,6

Li ppm 0,0

NH4 ppm 0,0

Ca ppm 67,4

Mg ppm 18,0

Sr ppm 0,2

Cl ppm 33,9

SO4 ppm 21,8

HCO3 ppm 269,9

 

How can I insert it in my system?

 

I have to modify the database for H2O?

 

please guide me step by step

 

thank you for your time

 

Hello:

 

All of the components you list are part of the default database, so no need for modification. Most of the components can be added directly via the add button in React:

 

add_species.jpg

 

The only additional modifications you need to make are decoupling HS-/SO4-- redox couple (via the Config - Redox Couples menu) if you want to include both reduced and oxidized sulfur, representing a system in redox disequilibrium with respect to the sulfur component. You'll want to make the a similar decision for NH4 (swap for NO3- or decouple). There are a number of threads on this forum that discuss redox equilibrium (example), so you might refer to those, as well as Craig's book.

 

Finally- you have three constraints for the carbonate system- pH, dissolved CO2 and bicarbonate. You'll want to pick two of those to constrain the carbonate system- three is over-constrained. If you choose pH and bicarbonate, for example, you can look at React's calculated speciation for HCO3- and CO2-- as a check for equilibrium.

 

I hope that helps,

 

Tom

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Hello:

 

All of the components you list are part of the default database, so no need for modification. Most of the components can be added directly via the add button in React:

 

add_species.jpg

 

The only additional modifications you need to make are decoupling HS-/SO4-- redox couple (via the Config - Redox Couples menu) if you want to include both reduced and oxidized sulfur, representing a system in redox disequilibrium with respect to the sulfur component. You'll want to make the a similar decision for NH4 (swap for NO3- or decouple). There are a number of threads on this forum that discuss redox equilibrium (example), so you might refer to those, as well as Craig's book.

 

Finally- you have three constraints for the carbonate system- pH, dissolved CO2 and bicarbonate. You'll want to pick two of those to constrain the carbonate system- three is over-constrained. If you choose pH and bicarbonate, for example, you can look at React's calculated speciation for HCO3- and CO2-- as a check for equilibrium.

 

I hope that helps,

 

Tom

 

 

 

maybe i don't explained you well, React doesn't give me a diagram.

 

I need that the Diagrams that i make with act2 have to consider for water in the sistem that particular water.

 

thanks for your help and for your time.

 

Fabio

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maybe i don't explained you well, React doesn't give me a diagram.

 

I need that the Diagrams that i make with act2 have to consider for water in the sistem that particular water.

 

thanks for your help and for your time.

 

Fabio

 

Hi Fabio:

 

Not sure I completely understand- but you can take the activity values predicted by the speciation calculation in React (look at the text output file) and use them to create a corresponding activity diagram with Act2.

 

Is this what you are looking to do?

 

Regards,

 

Tom

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