Abstract
The precipitation of calcium carbonate is well studied in many fields of research and industry. Despite the fact that, or perhaps because of the fact that, it is well studied in many fields, different approaches have been used to describe the kinetics of the precipitation process. The aim of this study was to collect and compare the data available in the literature and find a consistent method to describe the kinetics of growth and nucleation of the various polymorphs of calcium carbonate. Inventory of the available data showed that a significant number of the literature sources were incomplete in providing the required information to recalculate the kinetic constants. Using a unified method, we obtained a unique set of parameters to describe the kinetics for growth for calcite, vaterite and amorphous calcium carbonate (ACC) and nucleation for vaterite and ACC. Recalculation of the kinetic constants demonstrated that calcite confirmed there are two growth mechanisms within one polymorph, namely pure spiral growth and spiral growth mixed with surface nucleation. The spiral growth does not show second-order growth, which is typically attributed to it. Re-evaluation of the available nucleation data confirmed the suggested existence of a second pure ACC polymorph with a solubility product between 10−5.87 and 10−5.51 mol2 kgw−2.
Highlights
When a solution is oversaturated for vaterite, vaterite growth is preferred over calcite growth, as we show in this paper
The aim of this study was to find consistent parameters from the data available in the literature to describe the kinetics of growth and nucleation of the various polymorphs of calcium carbonate
The amount of and variance in both parameters and methods to study the kinetics of calcium carbonate crystallization currently in the literature are large
Summary
Calcium carbonate precipitation is a widespread phenomenon and a relevant topic for many fields of research and industry. Theories have been developed to describe the growth and nucleation kinetics of calcium carbonate minerals that may be used to determine the size, shape and number of crystals for a given solution composition and environmental conditions. Because calcium carbonate precipitation is such a prevalent phenomenon, much of the literature is dedicated to the kinetics of calcium carbonate precipitation. Despite, or perhaps because of, the vast amount of the literature available, various approaches have been used to describe the kinetics and determine the kinetic constants, which may lead to inconsistencies when comparing the different datasets and make it difficult to develop a unified approach which fits all available data. The fact that calcium carbonate crystals have multiple polymorphs complicates the already abstruse situation even further
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