complex problem

[PrestoConFuoco]

I have a problem:
Firstly, i have a solution with a lot of salts. Then some water is evaporated, and some salts precipitate (assume that M kg at all), and some solution (assume that N kg of it) of some composition remains in the equilibrium with solid phases.

But in real conditions some solution is taken with precipitated salts, about 10% mass. So mass of precipitate becomes 1.1*M, and mass of solution becomes (N - 0.1*M).
After first simulation i can SAVE solution 1. But for second simulation i need not N kg, but (N - 0.1*M).
The good option is MIX of obtained solution with "negative quantity of water". But as far as i understand, parameters of MIX keyword maybe only constant values, entered by the user, and the parameter i need depends on the quantity of precipitate (M kg).

How to deal with this problem?

[dlparkhurst]

If you are talking about the mass of water in hydrated minerals, it is accounted for and removed from the solution. The following example precipitates about 10 mol of CaCO3:2H2O, so about 20 mol of H2O are removed from solution. The solution that is saved has only 0.64 kg of water.

Code: [Select]

SOLUTION
-units mol/kgw
Ca 10
S(6) 10
EQUILIBRIUM_PHASES
Gypsum 0 0
SAVE solution 2
END


[PrestoConFuoco]

If you are talking about the mass of water in hydrated minerals, it is accounted for and removed from the solution. The following example precipitates about 10 mol of CaCO3:2H2O, so about 20 mol of H2O are removed from solution. The solution that is saved has only 0.64 kg of water.

Code: [Select]

SOLUTION
-units mol/kgw
Ca 10
S(6) 10
EQUILIBRIUM_PHASES
Gypsum 0 0
SAVE solution 2
END


No, i mean that extra water (not in structure of hydrates), that is taken by precipitate; i.e. it's somewhat like "wet precipitate".

UPD:
In fact, the question is: how to calculate some quantity within the BASIC interpreter so that it could be possible to use it in the MIX block.

Something like

Code: [Select]

-start
...
x = <some formula>
PUT(x)
...
-end


MIX 2
H2O -1
GET(x)  # this is a quantity of reaction added to system

(i know that it's not possible to use GET outside BASIC fragments, but this is something a would want to get)


[dlparkhurst]

You can write code from Basic and then run it with INCLUDE$. Look at example 8 (and 21).

You can also use IPhreeqc in programming languages of PhreeqcCOM in scripting languages (VBA in Excel for example).

[dlparkhurst]

Why not just add some hydration water to the formula for each of the minerals?

PHASES
NaCl+Water
NaCl:0.1H2O = Na+ + Cl- + 0.1H2O

[PrestoConFuoco]

You can write code from Basic and then run it with INCLUDE$. Look at example 8 (and 21).

You can also use IPhreeqc in programming languages of PhreeqcCOM in scripting languages (VBA in Excel for example).

Thank you! The "INCLUDE$" option is one of the great things of this world, it seems like PHREEQC really becomes a program for modeling technological lines ;)