For the last 3 days, I've been trying to understand Leroy index (=TAC/TH
). It allows to confirm or not the corrosion tendency of a water. With concentrations expressed in meq/l, the water is considered non-corrosive if the index is between 0.7 and 1.3.
I found an article written by Pierre Leroy with this self-explanatory graph that I want to use (the graph is an attachment with the name corrosion.PNG). But I can track down the function.
Can someone help me ?
The graph links the Saturatio (=([Ca2+]×[CO32-])/Ks'
) to the Larson Index (=([Cl-]+[SO42-])/[HO3-]
Moreover Leroy index defines different sectors :
- orange : pipe are covered in scale
- green : scales (carbonate calcium) protect the pipe from corrosion
- yellow : there are not enough scales to protect the pipe form the corrosion
- pink : there are no scale and the pipe corrodes
I really want to use the graph for my presentation but i can't track down the function linking Saturatio to Larson Index. I think my hypothesis are wrong.
Here are my hypothesis :
- [Ca2+]>>[Mg2+] TH=[Ca2+]
- TH - TAC = [Cl-]+[SO42-]
- TAC/2 > TA [HO3-]=TAC-2×TA and [CO32-]=2×TA
Thank you for your help