Mass-transfer and supersaturation in crystal growth in gels

Abstract

Supersaturation evaluation is an essential requirement to describe, confront and explain crystal growth experiences. However, in the particular case of crystal growth in gels, experiences are often described by attending to the initial concentration of reagents. This fact is wnnected with deficiencies in the theoretical quantification of mass-transfer, and therefore in both time and location prediction for the first precibitate. In this paper laboratory experiences have been specifically designed to test supersaturation evolution through an actual (finite) diffusion system. The problem is carried out by keeping into account several complexity factors: free ions as well as complexes and silica gel Na+ and C1-"unloading" are considered to evaluate the supersaturation.

Spatial and evolutionary aspects of nucleation in diffusing-reacting systems

“…The physico-chemical evolution of the system was studied according to the experimental path of Prieto et al [5]. In fact, this paper is a close following of an article recently published in this Journal [S], and consequently the expenmental details, that are identical to the previous paper, may be consuied there.…”

“…Hence, the knowledge of the system history involves finding the concentration and pH profiles, throughout the gel column, for successive diffusion times. The experimental testing of both, mass-transfer and pH evolution, is the most rigorous way for such an object, as Prieto et al [5] have already pointed out. From these profiles, the supersaturation values may be calculated.…”

Transient Porosity Resulting from Fluid–Mineral Interaction and its Consequences

“…Experiments designed to investigate these effects on the crystallization of sparingly soluble salts have been used by Prieto et al (1988Prieto et al ( , 1989Prieto et al ( , 1990Prieto et al ( , 1994 and Putnis et al (1995). The porous medium used is silica hydrogel and crystallization is induced by the counterdiffusion of ions from opposite ends of a diffusion column (Fig.…”

The kinetics of nucleation of solid solutions from aqueous solutions: a new model for calculating non-equilibrium distribution coefficients

“…By applying this expression to a binary solid solution with general formula BxC 1 _"A, and by taking into accollllt the Lippmann and Debye-Hiickel methods (extensively described in Glyrm and Reardon, 1990and in Prieto et al 1988 we can derive the supersaturation fimction:…”