The Coupling of Dissolution and Precipitation Reactions as the Main Contributor to the Apparent Field-Lab Rate Discrepancy

Abstract

Here, we revisit the hypothesis proposed by Zhu, Blum, and Veblen at WRI-11 for explaining the apparent discrepancy between field and lab rates. Substantial laboratory experimental data and numerical modeling experiments now support this hypothesis, and they show that the coupling between various dissolution and precipitation reactions leads to a quasi-steady state, at which dissolution reactions proceed at rates orders of magnitude slower than the far-from-equilibrium rates. The specific steady state in a system is determined by the relative rate constants, surface areas, and by the r – ΔGr relationships for the dissolution and precipitation reactions. Evaluation of reaction kinetics must not consider a single overall reaction as an isolated event, but as a part of a reaction network.