The Alkaline Dissolution Rate of Calcite

Area of Science:

• Geochemistry
• Environmental Science
• Mineralogy

Background:

• Calcite (calcium carbonate) dissolution significantly impacts global geochemical systems, including the CO2 cycle.
• Decades of research exist on calcite dissolution, yet a consensus on its rate remains elusive.
• Inconsistencies in reported calcite dissolution rates hinder accurate geochemical modeling.

Purpose of the Study:

• To identify the primary causes of variability in reported calcite dissolution rates.
• To propose benchmark values for alkaline calcite dissolution.
• To develop a method for applying these rates across diverse chemical and hydrodynamic conditions.

Main Methods:

• Systematic analysis of published calcite dissolution rate data.
• Evaluation of the influence of chemical and hydrodynamic parameters on dissolution rates.
• Interpretation of rate variations based on sample surface topography.

Main Results:

• Variability in reported calcite dissolution rates is primarily attributed to differing measurement conditions.
• When standardized, the spread in dissolution rates is significantly reduced.
• Sample surface topography plays a key role in the observed rate variations.

Conclusions:

• Benchmark values for alkaline calcite dissolution rates are proposed, reconciling existing literature.
• A novel method is presented to adjust dissolution rates for various experimental contexts.
• This work provides a more robust understanding of calcite dissolution for geochemical applications.