Reactive Crystallization of Copper Selenide at Very High Supersaturation: A Challenge to Classical Crystallization Theory for Sparingly Soluble Salts

Abstract

The nucleation rate for the precipitation of copper selenide, which has an extremely low solubility, was measured. The measured values of the kinetic parameter A and the thermodynamic constant B were compared with those calculated from theoretical considerations based on the classical nucleation theory. These calculated values were found to be physically meaningless. The nucleation work and the critical nucleus size were also found to be extremely small. It is proposed that a new conceptual model of nucleation in highly supersaturated solutions needs to be considered. A new model from literature, that proposes stable pre-nucleation clusters at high supersaturations, is presented and found to be promising. This new model would mean that the classical nucleation theory of stochastic attachment and detachment of monomers would no longer apply. The new model would also account for the very small nucleation work and the small critical nucleus sizes found in this study.

Role of Water During Crystallization of Amorphous Cobalt Phosphate Nanoparticles

“…Diffusion is enhanced in highly supersaturated solutions which leads to an increased tendency to crystallize (shorter lifetime of amorphous solid) . Amorphous solids precipitating at high supersaturations are not in conflict with a classical kinetic crystallization pathway, but the application of the classical model of equilibrium states may be limited …”

“…44 Amorphous solids precipitating at high supersaturations are not in conflict with a classical kinetic crystallization pathway, 45 but the application of the classical model of equilibrium states may be limited. 46 In addition, we performed precipitation experiments with different starting concentrations, reaction times, and temperatures (see Table 1). The reaction proceeds to some extent during centrifugation, but the results were not affected by shorter centrifugation times (1 and 3 min).…”

Thermally Highly Stable Amorphous Zinc Phosphate Intermediates during the Formation of Zinc Phosphate Hydrate

“…Short reaction times and high supersaturation are expected to favor the formation of AZP. The formation of amorphous compounds at high supersaturations is not in conflict with a classical kinetic crystallization pathway, but the classical model of equilibrium states appears to have limitations . To understand the formation of amorphous zinc phosphate and its transformation in solution with time, the precipitation experiments were conducted at time intervals ranging from 5 s to 1 day with different starting concentrations (ranging from 10 to 300 mM) of the zinc nitrate and sodium phosphate solutions.…”

Aggregation of growing crystals in suspension: I. Mumtaz revisited

“…Mumtaz's work has found applications in industrial crystallisation (Braun et al, 2004;Brunsteiner et al, 2005;Chen et al, 2004;Chen et al, 2003;Chew et al, 2004;Falk et al, 2011;Hollander et al, 2003;Ilievski, 2001;Ilievski and Livk, 2006;Kramer and Jansens, 2003;Li et al, 2001;Livk and Ilievski, 2007;Rielly and Marquis, 2001;Wang et al, 2006;Yokota et al, 1999;Zauner and Jones, 2000), precipitation (Lakshminarayanan and Valiyaveettil, 2003;Lewis and Mangere, 2011;Lindenberg et al, 2008;Lawler, 2008, 2010;Wagterveld et al, 2012;Wan et al, 2011), nanoprecipitation (Jia et al, 2008;Pujol et al, 2004;Schwarzer and Peukert, 2005;Schwarzer et al, 2006), population balance modelling (Balakin et al, 2012;Briesen, 2006;Briesen, 2007;Derksen, 2002;Hollander et al, 2001a;Hollander et al, 2002;Hollander et al, 2001b;Mersmann et al, 2002;Reinhold and Briesen, 2012;Sgraja et al, 2010) and colloid science (Gruy, 2012;Kind, 2002).…”