Chemical, Physicochemical and Crystal-Chemical Aspects of Crystallization from Aqueous Solutions as a Method of Purification

Smolik, Marek

doi:10.5772/48009

Cited by 4 publications

(8 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although this rule of thumb has been demonstrated for inorganic compounds in water, there are also many exceptions. Smolik reported that 72% of the explored inorganic compounds in water were consistent with Ruff’s rule. The Hume-Rothery rule , is well-known in metallurgy as a way to estimate when metals and elements form solid solutions: e.g., as different types of alloys.…”

Section: Introductionmentioning

confidence: 80%

“…The distribution of the impurity between the solid and liquid phases in the crystallization can be expressed by a so-called distribution coefficient (other names are partition coefficient, purification factor, and segregation coefficient). The distribution coefficient, D , can be written as for impurity i. Although the representation of the distribution coefficient is mathematically simple, in a dynamic process it represents the distribution of the impurity between the solid and liquid phases at the exact time the solid is formed.…”

Section: Discussionmentioning

confidence: 99%

“…However, a minimum at 20–40 wt % MeOH in H 2 O seems to be present, at which point the D values again start to increase. If the crystallization is carried out close to equilibrium conditions, then the distribution coefficient can be expressed on the basis of thermodynamic properties where a denotes the activity of component i or p in the solid or liquid phase.…”

Section: Discussionmentioning

confidence: 99%

“…The likelihood and extent of this substitution in the lattice is related to the properties of the impurity relative to the properties of the product. Influencing properties for inorganic compounds have been reported by Smolik: e.g., solubility of the impurity in the crystallization solvent (Ruff’s rule), similarity in crystal structures of the product and impurity, molecular volume of the impurity, similarity in ion charge (for cations), geometry of impurity, and polarity. Meenan et al similarly outlined the chemical dissimilarity in terms of molecular volume, ionic radii, and steric interactions as determining factors.…”

Section: Introductionmentioning

confidence: 97%

“…In this scenario the impurity is integrated into the lattice of the product during the crystallization. There have been several studies and theories around the nature of this impurity entrapment mechanism, often for inorganic systems and metals and for melt crystallization (for details see overviews by Chernov, Smolik, and Meenan et al). The predominant theories revolve around surface adsorption, mass transfer, crystal defects, and solid solutions.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Material Impurity Distribution of Lattice-Incorporated Impurities in Salicylic Acid

Teerakapibal

Linehan

et al. 2020

Crystal Growth & Design

View full text Add to dashboard Cite

The mechanisms of purging structurally similar impurities in solution crystallization have been evaluated using the model compound salicylic acid. Of the 11 added impurities, 3 showed appreciable entrapment in the solid phase: viz., salicylamide, anthranilic acid, and benzoic acid. X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), and the use of a previously reported solubility-limited impurity purge (SLIP) test have shown that the impurities are entrapped by a lattice incorporation mechanism. Impurities become integrated within the product crystals during the crystallization by forming terminal solid solutions. Most of the impurity entrapment was found to take place very early in the crystallization, immediately after seeding. The least entrapment occurred at the end of the crystallization, despite the mother liquor being enriched in impurities. These changes caused purity variations in the solids, which were not properly captured by the average value. A mathematic framework was developed to afford the material impurity distribution (MID), which represents the mass-based impurity profile across a material based on the SLIP test. It is shown that the level of impurities in the crystallized material is far from constant and in fact varies by orders of magnitude, in many cases by more than 20 times. These differences give rise to changes in the physical properties of salicylic acid, as exemplified by a reduction in crystallinity, a lower and broader melting event, and a doubling of solubility.

show abstract

Section: Introductionmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Material Impurity Distribution of Lattice-Incorporated Impurities in Salicylic Acid

Teerakapibal

Linehan

et al. 2020

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

Evaluation and Analysis of Trace Impurity Migration Pathways on the Design of Highly Efficient Solution Crystallization-Based Purification Process

Zhou,

Sun,

Wang

et al. 2024

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

Separation and purification of fine chemicals with minor or trace amounts of impurity, for instance, metal ions, to produce high-end and high-pure chemicals has been of utmost importance in recent years. Understanding the key factors and impurity migration pathways is critical to designing a highly efficient crystallization-based purification process. This study combines theoretical models with experiments to analyze the impurity migration mechanism and obtain the key factors of purification for the optimization of the solution crystallization process, using a model compound ferrous sulfate. The migration and deposition of trace amounts of Mg 2+ impurity within ferrous sulfate heptahydrate crystals were examined by a general workflow, where the liquid inclusion was found to be the dominant impurity incorporation mechanism. Given that the liquid inclusions are strongly influenced by crystallization kinetics, we quantified the effects of the supersaturation ratio and temperature on inclusion formation using optical microscopy and ICP analysis. The results indicated that higher temperatures and a greater supersaturation ratio increase growth rates and promote the formation of mother liquor inclusions within the crystals, leading to poor impurity removal efficiency. Furthermore, based on the crystal growth kinetics, we found that with the increase of supersaturation ratio, the growth mechanism of ferrous sulfate heptahydrate changes, leading to a significant increase in distribution coefficient and poor separation effect. Finally, the formation mechanism and process design to reduce liquid inclusion have been discussed.

show abstract

Crystallization of nickel sulfate and its purification process: towards efficient production of nickel-rich cathode materials for lithium-ion batteries

Choi,

Azimi

2023

RSC Adv.

View full text Add to dashboard Cite

show abstract

Chemical, Physicochemical and Crystal-Chemical Aspects of Crystallization from Aqueous Solutions as a Method of Purification

Cited by 4 publications

References 21 publications

Material Impurity Distribution of Lattice-Incorporated Impurities in Salicylic Acid

Material Impurity Distribution of Lattice-Incorporated Impurities in Salicylic Acid

Evaluation and Analysis of Trace Impurity Migration Pathways on the Design of Highly Efficient Solution Crystallization-Based Purification Process

Crystallization of nickel sulfate and its purification process: towards efficient production of nickel-rich cathode materials for lithium-ion batteries

Contact Info

Product

Resources

About