how to extract an element from the fluid

[Jowitawl]

Hello,

I am not sure if it would be possible to resolve this problem in PHREEQC. The problem is that i have a mixture of two fluids - groundwater with Loats of amorphous silica mixing with cold water rich in Mg. Thus, we are trying to mix these two waters and heat up to 85 ?C in the reactor, however, the amount of silica is too much, so we?ve decided to try to remove Mg as our samples have quite high pH. Thereby, i was considering REACTION, REVERSE_MODELLING and KINETICS functions to further understand what is causing the extraction of Mg out of the fluid and maybe how to speed it up? Do you think it is possible?

Many thanks for your help!

Jowita

[dlparkhurst]

I think it is possible to define the solutions, do the mixture, and heat the solution with a PHREEQC script. That will allow you to calculate saturation indices. You will have to consider which minerals should precipitate and the validity of the thermodynamic data for your system.

[Jowitawl]

We tried to do that, eventually we reached the saturation indices on very low values, but is it possible to extract it completely? 

[dlparkhurst]

I need to see your script to know what you are trying to do and how you set up your calculation.

[Jowitawl]

The problem is that after some time if we won?t extract Mg it will form magnesium silicate and after some time, even from the lowest SI... Therefore, i am trying to figure out how to remove it completely. We were thinking about rising the Mg membrane to not to regulate magnesium concentrates, but i am not sure if that would help, thus the idea of trying to remove it completely or maybe let it react with some other aqua species to avoid forming magnesium silicate. This is why i am asking if it would be possible to make such a model in PHREEQC, as we tried mixing these fluids in different ratios but still after time the formation appeared.

Thank you for your answer!

[dlparkhurst]

I need to see your script and database to know what you are trying to do and how you set up your calculation.

[Jowitawl]

I understand, the issue is that i am still struggling with setting up the formula in PHREEQC. Thats why i was asking if there is any formula that would withdraw Mg before mixing with silica geothermal water. I am sorry for confusion.

[dlparkhurst]

Sorry, I can't help you without your script, whether it works or not.

[Jowitawl]

I understand, I will send it in few days, i need to think about it :)

Thank you for your answer!