thais98

Hello, I have a doubt regarding sliding fugacity path. I would like to know at what rate the fugacity increases when reacting with a solution, for example fCO2 with a simple water solution. If it's linear or not. Thank you.

Hello, Thanks for the reply. I think you're right, the kinetics were too fast, so I increased the rate constant for both of the minerals and the reaction ran without any problem. When increasing the rate constant, I only guessed a value that would make the reaction run , about 7.76e-17 for diopside in a time of 10.000 years. Is it correct? I'm attaching the file. One more question, "Newton-Raphson didn't converge after 999 iterations, max residual = 2.89e-10, Xi = 0.9991" this error means that the kinetics are too slow for the reaction ? Amostra 8 do poço (anortita e diopsidio).rea

Hello, Yes, I tried adding the glass in the thermo database. But, for each element in the basalt glass formula, there's a specific number of molecules. Ca0.015Fe0.095 Mg0.065Na0.025 K0.01Al0.105 S0.003Si0.5O1.35 : this is the formula of the basaltic glass. I'm not sure how to add those values in the thermo database. Thank you Thais

Hello, I am reading an article and the author adds the kinetic parameters to the basaltic glass, and also the logK, which is -99. So, the author added the glass as a mineral in the thermodat? But adding the basaltic glass as a mineral is too complex, right? My goal is to try to do the same process to the glass as I did to the minerals of the basalt, using kinetic. I attached the Table of the kinetic parameters he used for the reaction.

Hello, Yesterday I ran a reaction of a water from a aquifer with Anorthite and Augite. The reaction took SO LONG to complete, about 21 hours, and it was only for 100 days...Previously, I had reacted the water with only Anorthite or only Augite and the reaction happenned fast. Is it normal for the reaction take so long to be completed? The other problem is that, after the reaction was completed, I wasn't able to plot the results. When trying to open it, I got the following error: "Input file C/Users........ is not in correct format. Do you want to read a different file?" Now, I'm afraid to close the program because then I would loose everything I did 😧

Hello, So the best way to add basaltic glass is by adding the oxides in the reactant pane? Considering that basalt glass is made of different oxides, I could take a % of it that relates to another mineral and add this % of basaltic glass to the mineral's composition. I hope you could understand it. I will try to react the oxides and see the output, if I get any problems I will post it here! Thank you !

Hello, I am having some doubts on how to add a basaltic glass in the reactant pane. I've seen some other posts regarding basaltic glass reaction, but I didn't understand how to add the basaltic glass oxides in the thermo.dat. Or should I rather input the minerals that make up the basaltic glass? Apart from the glass, I am adding the other minerals from the basalt. So, could I add to the basalt's minerals, e.g to Albite, a % of the basaltic glass (that would represent % of Al and K for example?)? But then, the surface area of the basaltic glass would be totally different from the other minerals , right?

Hello, I tried to change the kinetic minerals to simple, the CO2 fugacity decreased a lot and the pH increased. However, the porosity didn't decrease, when it should have. Regarding the mineral volume, I changed it to wt% but the output was the same. I will try sending a message to the author. Thank you for the help!

Hello, Oh, I think I misunderstood it. Thank you ^^ I'll post there from now on.

Hello, Thanks for the answer! Regarding the parameters I used are the same same as the author's. They added a table with the kinetic rate parameters of the minerals that I input in the results, so I guess they constrained the mineral reaction as kinetic. The authors don't specify the minerals that dissolve and precipitate. But all of the minerals that I added have a %volume of the compositional mineral assemblage from the aquifer and the rock. I did what you suggested, changed the mmol/kg to volume %, but I got the following error: -- Error: Porosity of node 0 is too small: -0.069483 . I'm not sure what it means.

Hello, So, I'm trying to follow the steps from a paper, in order to understand the process they made in the software. Firstly, they injected CO2 fugacity in a water sample and the result is an increase in the CO2 fugacity to 68.88 and an increase in the porosity. On the second step, they stop injecting CO2.From what I understood, the resulted solution of the reaction with CO2 is reacted with the minerals that constitute the rock. Their results showed a big decrease in the CO2 fugacity (from 68.88 to 3), porosity and an increase in the pH. However, when I tried to replicate this second step, I didn't get this result at all. My results indicate only a slight decrease in the CO2 fugacity (from ~68 to 63 ). In relation to the pH, something strange happens, which I couldn't figure out why. There's a increase peak, but not considerable in the pH, then it decreases a little bit and then increases again, but actually it increases nothing, only 0.2. And regarding the porosity, it happens quite the same thing as the pH. I'm not sure what I'm doing wrong, I think maybe there's something to do with the reactants that I added. I'm attaching the file of the reaction of the step 2 I made. Thank you ! fase 1 react luben CO2 mais agua 2.rea

Hello, Thank you ohh okay, so I'll continue posting here

Thank you! I thought that when i upgraded my account I'd be able to post topics on the specific forums, such as REACT.

Hello, Recently, I purchased the GWB Professional, and I needed to change the serial number in my profile of the GWB forum. However, I can't find the place where I can change it. Could somebody help me ? Or I'll have to create another account and add the new serial number? Thanks

Hello, Thank you very much for your answer. I saw it again and you are right!

Happy new year everybody So, apparently there's a limitation of the saturation index of the minerals when using the REACT, it doesn't get supersaturated. No matter how much of a mineral I add to the reactants, I always get the same saturation index for calcite. I would like to know if there's a way that I can change that, in order to get a higher S.I for the minerals. In the file I attached, the CO2 that was left in solution is 3.444e-06 , and that's the maximum it's consumed when reacting with the other minerals. Thank you ^^ amostra 8- reagindo com rocha3.rea

Hello, sorry for sending more messages here 😅 I was trying to increased the moles of rock reacting to the fluid to see if the amount of calcite precipitanting would be higher, but apparently no. The maximum of SI that it reaches is 0. I'd like to know if there's something that is limiting the precipitation of calcite or if the software limits SI to 0 and how I can solve this problem. Thank you

Hello, thank you for the reply! I was able to understand a bit more after your explanation , thank you very much !

Hello, thank you for the reply. Oh I see, so the file that I sent had a nucleus density of 1000 cm2/cm3, and this one precipitated calcite. One of the things that I'm not understanting is what exactly is the nucleus density. Because when I ran the file with nucleus density of 0 cm2/cm3 there was no calcite precipitated, but instead aragonite. I'm not sure what would be the correct value to the nucleus density, whether or not I can input any value > 0 to precipitate calcite. Regarding the pre-exp factor and Activation Energy of calcite, I selected those values from another article, since I'm not sure how I can calculate it. I'm not sure if I need to do calculations to get those values or are they already established? You can see that I have many doubts regarding this software xD Thank you

Hello! My knowledge of geochemistry is kinda poor and I've recently started using the GWB software with the Professional Demo. I need to run some reactions to see the amount of calcite that precipitates when reacting the water sample rich in CO2 with basalt minerals, such as anorthite, albite and diopside. So, what i'm doing is: adding those minerals as kinetics in the reactants and also, the kinetics of calcite (the one that I want to precipitate). I'm setting the concentration of calcite to 0 and rate constant of 5.01e-5 (i'm not sure if that's correct) . However, when I run the reaction, and go to the graphic, I don't see the mineral calcite precipitating, only the ones that I added a concentration. I was using PHREEQC before and regarding this step (not the kinetics) was much easier to understand. I'm attaching the file, so if someone could take a look at it , i'd be happy amostra 8- reagindo com rocha.rea