Aragonite and Calcite precipitation question

[Khaled]

Hi everyone,

I wanted to ask two questions

1- Can Aragonite precipitate and transform to Calcite in a desalination process, and which one precipitate first or both of them precipitate or which one is stable?
2- Any reference explained specifically about the first question?

[dlparkhurst]

From a purely thermodynamic perspective, calcite is more stable (smaller log K) than aragonite for all temperatures 0-100.

Code: [Select]

SOLUTION
REACTION_TEMPERATURE
0 100 in 11
USER_GRAPH 1
    -headings               temp Calcite Aragonite
    -axis_titles            "Celsius" "LOG K" ""
    -initial_solutions      false
    -connect_simulations    true
    -plot_concentration_vs  x
  -start
10 GRAPH_X TC
20 GRAPH_Y LK_PHASE("Calcite"), LK_PHASE("Aragonite")
  -end
    -active                 true
END
Aragonite can form in some environments, you'll have to look at the literature, but thermodynamics says it should transform into calcite (although it is undetermined how fast that would happen).