I am not able to estimate the amount of arsenopyrite consumed in my 1D RTM

[Kirkoff Xn]

Hi there,

I am able to run a 1D RTM mimicking injection of oxygenated water into a reduced aquifer zone with possible mobilization of arsenic species from arsenopyrite oxidation and dissolution. However, when I try to check to what extent pyrite and arsenopyrite have been oxidized and consumed, forming Fe(OH)3 (ppd), I can only see both pyrite and  Fe(OH)3 (ppd), but I cannot see arsenopyrite mineral phase. Can you help resolve this issue? I am attaching both the RTM file and the database I used.

Thank you ,

As fate_no BF.x1t thermo_upd.tdat

[Jia Wang]

Hello,

Thank you for attaching your input file. From your input file, it looks like you are titrating a set amount of mass into the entire domain over the course of the simulation. When you add minerals as simple reactants, they are added to the domain incrementally throughout the simulation to alter the composition of your system. Was this what you intended? Perhaps you need to consider swapping in minerals if they can be treated as in equilibrium with the initial system or set them as kinetic reactions instead.

If you plot the Mineral Saturation index for Arsenopyrite2 you will see that the mineral is undersaturated with respect to the fluid, so any simple Arsenopyrite2 added will not remain in the solid phase. You can check the mass of Arsenopyrite2 added in by plotting the Variable type "Reactants properties".

If you would like further help with troubleshooting, please provide a bit more context as to what you are trying to do.

Hope this helps,
Jia Wang
Aqueous Solutions LLC

[Kirkoff Xn]

Hi Jia,

Thanks for your thoughtful reply.

This was just a simple RTM simulating injection of oxidizing surface water into an aquifer during an ASR operation.

The code have been taken from  Lazavera et al., 2015 paper, and that was later applied in Horne et al. 2022 paper.

In their code, they did not swap any mineral phase in equilibrium in the initial phase pane, and if I try to do so, It does not work (or converge).

More specifically, I don't know how to set up pyrite and arsenopyrite separately in the initial pane.

I'd really appreciate your help in this.

Thank you,

[Jia Wang]

Hello,

Thank you for providing additional details. I do not have access to the models presented in Lazavera et al., 2015 and Horne et al. 2022. If you are trying to replicate their results or are working with their script but not seeing the expected results, I would suggest that you contact the corresponding authors on the publications.

Swapping a mineral for a component in the basis tells the program to calculate that component's dissolved concentration in equilibrium with that mineral. You would only want to do this if you can assume that the mineral is in equilibrium with your initial fluid. Based on what you said above, it doesn't sound like this would be the appropriate path. You can find more about configuring your system in chapter 2 of the GWB Essentials Guide.

Best regards,
Jia