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l have just bought a GWB software and l want to speciate the mine water that l am working on but l am getting an error as below

Solving for species distribution.

Loaded: 159 aqueous species,

148 minerals,

7 gases,

0 surface species,

19 elements,

15 oxides.

*N-R didn't converge after 999 its., maximum residual = 1, Xi = 0.0000

Largest residual(s):

Resid Resid/Totmol Cbasis

--------------------------------------------------------

Al+++ 8.358e+206 1 1.#QO

B(OH)3 6.241e+201 1 1.#QO

Ba++ 1.526e+201 1 1.#QO

Ca++ 1.505e+201 1 1.#QO

Cr+++ 2.861e+203 1 1.#QO

Cu++ 2.052e+201 1 1.#QO

Fe+++ 2.652e+203 1 1.#QO

K+ 5.12e+200 1 1.#QO

Mg++ 3.356e+202 1 1.#QO

Mn++ 8.049e+201 1 1.#QO

Na+ 1.084e+201 1 1.#QO

Rb+ 1.812e+200 1 1.#QO

Sr++ 1.28e+201 1 1.#QO

Zn++ 1.906e+201 1 1.#QO

Cl- 1.37e+202 1 1.#QO

SO4-- 2.306e+202 1 1.#QO

HCO3- 2.438e+202 1 -1.#IO

--------------------------------------------------------

my input file is attached.

Godfrey.

field trip water analysis.gss

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Hi Godfrey:

The zero values are not allowable- I would start by removing them (or replacing them with n/d notation in GSS).

Hope that helps,

Tom Meuzelaar

RockWare, Inc.

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Hi Godfrey:

The zero values are not allowable- I would start by removing them (or replacing them with n/d notation in GSS).

Hope that helps,

Tom Meuzelaar

RockWare, Inc.

HI Tom

The error is still coming up. You see after running the Spec8 it gives this:

Solving for species distribution.

Loaded: 159 aqueous species,

148 minerals,

7 gases,

0 surface species,

19 elements,

15 oxides.

l want to find out the % distribution of the 158 species and the 148 minerals and the saturation indices of these minerals. Are you by any chance planning to have a training here in South Africa by any chance?

Regards

Godfrey.

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Hi Godfrey,

A few things. I deleted all the entries for which no analytical concentration was available. Your Eh value is entered as 442.2 V - this should surely be 442.2 mV. Just with these changes I was able to get a solution in SpecE8, although with a rather large charge imbalance. This is possibly due to missing analytical data or the way the data were input. I believe where you have Cr+++ listed in mg/l as Cr, and Mn++ in mg/l as Mn, that this is unnecessary. Generally you do this for the polyatomic molecules like B(OH)3 or SO4-- when you have a measurement for Boron or Sulfur, not the whole molecule.

Make sure you are being careful when entering in values for redox sensitive elements like Iron or Copper. Fe++ and Cu+ are the default basis species, and you should define the Iron and Copper components in this way if you believe your system is at equilibrium. In GSS you chose Fe+++ and Cu++, hence decoupling the Fe++/Fe+++ and Cu+/Cu++ redox pairs, indicating your system is in redox disequilibrium. Generally you choose this option if you have analytical measurements for both Fe++ and Fe+++. By decouple Fe+++ and listing no input for Fe++, you prevent all ferrous iron species or minerals from forming. See the chapter on Redox disequilibrium chapter in Craig Bethke's Geochemical and Biogeochemical Reaction Modeling, or go to the SpecE8 section of the GWB Essentials Guide and look for the Redox disequilibrium section.

Finally, you can calculate species concentrations and mineral saturations in GSS or SpecE8. In GSS you simply go to data - calculate - mineral saturations. I'll post both my GSS spreadsheets and SpecE8 input files.

Hope to help,

Brian Farrell

Aqueous Solutions

Makers of The Geochemist's Workbench

PS I am not sure about our current plans for short courses. We will certainly keep South Africa in mind.

Godfrey.sp8

Godfrey_GSS.gss

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