Neutralization reaction

[lilifamozurrutia]

Hi everyone!
I wonder if it is possible to simualte a neutralization reaction such as: Mg(OH)2 + H2SO4
I have the mangesium hydroxide in a 50-50 water slurry and concentrated H2SO4 to 98%. I would like to know the obtained solution and later on change the temperature an precipiate the salts (that part I know how to do).
However I do not know how to input the acid. I have tried several ways and I always get a convergence error.

Any ideas? or is it just not possible?

Thanks

[dlparkhurst]

I think it is not possible to define a pure (or 98% pure) H2SO4 liquid with SOLUTION.

However, you can add H2SO4 as a REACTION. I calculate that a 1:1 by wt H2O:Mg(OH)2 slurry would have 17.146 mol of Mg(OH)2(s) for a liter (1 kg) of water, and a liter of pure H2SO4 liquid would contain 18.65 mol H2SO4.

The following calculates the titration of the slurry (1 kg water, 1 kg Mg(OH)2(s)) with one liter of pure H2SO4. You should use pitzer.dat for the database.

Code: [Select]

SOLUTION 1
END
EQUILIBRIUM_PHASES 1
Brucite  0  17.146  # moles in 1 kg Mg(OH)2 = 1000/GFW("Mg(OH)2")
END
REACTION 1
# Pure H2SO4, 18.65 mol/L = 1.83 kg/L / (98.08 g/mol * 0.001 kg/g)
H2SO4 18.65
1 in 100 steps # 10 L addition
END
INCREMENTAL_REACTIONS
RUN_CELLS
-cell 1
USER_GRAPH 1
    -headings               L pH Mg(OH)2(s)
    -axis_titles            "H2SO4 added, liters" "pH" "Mg(OH)2(s)"
    -initial_solutions      false
    -connect_simulations    true
    -plot_concentration_vs  x
  -start
10 GRAPH_X TOTMOL("S") / 18.65
20 GRAPH_Y -la("H+")
30 GRAPH_SY EQUI("Brucite")
  -end
    -active                 true


[lilifamozurrutia]

I tried adding the acid in the REACTION before but it didn't work. I think I did not define the Mg(OH)2 slurry properly. Now, using your code, it works fine.

Thank you very much!