Version 2 2016-11-02, 20:04Version 2 2016-11-02, 20:04
Version 1 2016-09-23, 19:04Version 1 2016-09-23, 19:04
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posted on 2016-11-02, 20:04authored byJean Colombani
Due to the widespread
presence of calcium carbonate on Earth, several
geochemical systems, among which is the global CO2 cycle,
are controlled to a large extent by the dissolution and precipitation
of this mineral. For this reason, the dissolution of calcite has been
thoroughly investigated for decades. Despite this intense activity,
a consensual value of the dissolution rate of calcite has not been
found yet. We show here that the inconsistency between the reported
values stems mainly from the variability of the chemical and hydrodynamic
conditions of measurement. The spreading of the values, when compared
in identical conditions, is much less than expected and is interpreted
in terms of sample surface topography. This analysis leads us to propose
benchmark values of the alkaline dissolution rate of calcite compatible
with all the published values, and a method to use them in various
chemical and hydrodynamic contexts.