Acid Mine Drainage Inverse Modeling

[Loreto Martínez]

Hello!
I am new to PHREEQC and I write this post because I have found many solutions using this forum, but I have reached a point where I don't know what else to do. I am currently modelling the formation of acid mine drainage, for which I am using some data from kinetic tests (humidity cells) and I wish to model the mineral evolution of the system starting from this information. Particularly I would like to know the behaviour of pyrite in time (for every cell result represents a different time state of the system). I started my problem by adding two solutions (which are the results of my first two cells). After this, I tried to incorporate Inverse modelling by defining the main phases that I know are found for this soil. However, when I run the Inverse Modeling, Pyrite does not appear as a result between the output phases, but I cannot understand the reason for this. I have already defined Pyrite as a -phase in the input file. I attach my input for this first two iterations looking if someone has already had this problem or could help me solve it.
Thank you so much for your time and help!

[dlparkhurst]

It does not look like solution 2 evolved from solution 1. Cl and SO4-2 decrease, which is the opposite of expectation. Reconsider your conceptual model. Is the initial solution pure water in each case (pure water to solution 1, pure water to solution 2)?

[Loreto Martínez]

These results correspond to an actual laboratory test result, therefore I had not questioned the verisimilitude of the information. I am now working with a sample that evolves lowering its pH and increasing the content of SO4-2 and Cl in time. I also removed the line indicating water as the initial solution.

Thank you so much for your help and time!