Temperature Dependence of Calcite Precipitation
Problem
The precipitation/dissolution of calcite depends on the temperature. What happens with the example solution C1.sol when the water temperature rises above 35?
Answer
Click on Open and select the sample C1.sol; then, button Reac and activate the two checkboxes “change of temperature” and “plot titration curves, etc.”. Start the calculations by clicking Start.
The program runs a sequence of calculations from 0 to 70.1 The results are automatically displayed in diagrams. Two examples are shown below.
The first diagram plots the pH and DIC as a function of T. (In the dropdown lists you can select any element or ion.)
The second diagram plots the dissolved Ca and the amount of precipitated calcite. Precipitation starts above 37.
In the same way, you can also switch from “ELEMENTS” to “IONS” in the dropdown list and select the species “CO2”. Increasing the water temperature decreases the amount of CO2 dissolved in water and causes calcite to precipitate at 37.
Hint. Please use the right mouse button to autoscale or zoom the diagrams.
Footnotes
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In general, you can select and set any other T range in the list boxes. ↩