HELP! How to write PhreeqC input for calcite dissolution

[yijing84]

I am sorry to post here to ask for help in writing phreeqC input.
I never done any modelling before, but I have to learn to use it for my new research. (please pardon my poor knowledge of modelling)
I know how to use the available examples and change the details to what I want to model, but when it comes to a quite different topic, I am lost!

Ok...now going to my question.
I would like to know the calcite dissolution when added different volume of lactic acid.
For example, if I fix the calcite amount at 1g and the lactic acid at 200mM, how much Ca2+ ion will I produce when I add different volume of acid into 1g of calcite (let's say from 0.1-2ml).
Other conditions are constant, i.e. open system, 200mM lactic acid, pressure, temperature 25C, calcite amount, etc.
The only variable is the volume of acid.

I did the calculation of Ca2+ ion concentrations at different acid concentration, but I don't know how to modify it to study about the acid volume.
I would be very grateful is someone could help me.
Thank you in advanced! ^^

[dlparkhurst]

If the calcite does not completely dissolve, the concentration of Ca will be the same, regardless of how much acid you add.

[yijing84]

I see. Thank you for your explanation. :)

[AnnaJulIQ]

how to model lactic acid? i'm trying to simulate it for my project and i'm new to this