How to use the saved aqueous solution+solids i the subsequent simulation?

[Titanium]

I want to simulate the carbonation of hardended ammonium magnesium phosphate cement. Firstly, I simulate the batch reaction of MgO and NH4H2PO4 using INCREMENTAL_REACTIONS due to the high cencentration of NH4H2PO4 solution and save the calculated results. subsequently I use the saved solution and equilibrium_phases to simulated the carbonation products with stepwise addition of CO2 and H2O. There are two equilibrium_phases in my simulation, the SELECTED_OUTPUT just output the dissolution of the equilibrium phases of the previous reaction with CO2 and H2O, and there is no carbonation products at all. Here is my input file.
SOLUTION 1
end
USE solution 1
REACTION
NH4H2PO4 1
5 moles
SAVE solution 1
END
INCREMENTAL_REACTIONS
USE solution 1
REACTION 1
MgO 1
10 mol in 10
EQUILIBRIUM_PHASES 1
MgO    0 0
MgHPO4·3H2O  0 0
MgNH4PO4·6H2O   0 0
(NH4)2Mg(HPO4)2·4H2O   0 0
END
USE solution 1
USE equilibrium_phase 1
USE reaction 1
SAVE SOLUTION 1
SAVE EQUILIBRIUM_PHASES 1
END

REACTION 2
    CO2(g)     1
    H2O(l)     2
    35 moles in 1000 steps
USE SOLUTION 1
USE EQUILIBRIUM_PHASE 1
USE REACTION 2
EQUILIBRIUM_PHASES 2
    Brucite   0 0
    MgO       0 0
    MgCO3:3H2O(Nesquehonite) 0 0
    MgHPO4·3H2O  0 0
    MgNH4PO4·6H2O   0 0
    (NH4)2Mg(HPO4)2·4H2O   0 0
SELECTED_OUTPUT 2
    -file                 MAPC.sel
    -equilibrium_phases   Brucite  MgO     MgCO3:3H2O(Nesquehonite) 0 0  MgHPO4·3H2O  MgNH4PO4·6H2O (NH4)2Mg(HPO4)2·4H2O

[dlparkhurst]

You only get one EQUILIBRIUM_PHASES for the reaction calculation. In the final calculation, USE equilibrium_phases 1 is used in preference to EQUILIBRIUM_PHASES 2.

Just add the carbonate phase to EQUILIBRIUM_PHASES 1. At the beginning, there is no carbon in the system, so you will get a warning, but none of the carbonate phase can precipitate until you add CO2. Starting with 0 moles of the phase, the carbonate phase cannot dissolve until some has precipitated.