Peculiarities of Calcite Interaction with Carboxylic Acids

Abstract

This research examined the interaction of calcite with carboxylic acids (formic, citric, malic, and oxalic acids) at temperatures ranging from 22 to 80 °C. Experiments were carried out using an open batch reactor to prevent the impact of aggressive CO₂ byproducts. The dissolution rate was determined to be a combination of the chemical interaction of calcite with acid and the promotion of dissolution by calcium carboxylate salt. When acid concentrations are low, the surface chemical reaction acts as a limiting step with an activation energy of 42 kJ∙mol^-1. Conversely, at higher acid concentrations, the formation of calcium carboxylate with reduced solubility hinders its dissolution, thereby restricting the overall calcite dissolution process. Both stages are significantly influenced by temperature. The specific functional groups present in the acids aid in the formation of surface species with Ca²⁺ cations. The properties of these functional groups impact the stability of the species and the dissolution of calcite.