The methods described in this section preferably should be used on solutions that are still warm, as initiating crystallization on already cool or cold solutions will cause too rapid a crystallization. The easiest method to initiate crystallization is to scratch the bottom or side of the flask with a glass stirring rod Figure 3. Crystallization often begins immediately after scratching, and lines may be visible showing crystal growth in the areas of the glass that were scratched Figure 3.
Although there is no doubt that this method works, there are differences in opinion as to the mechanism of action. Chemomechanics of salt damage in stone. Noiriel, C. Intense fracturing and fracture sealing induced by mineral growth in porous rocks.
Chemical Geology. Tsui, N. Crystallization damage by sodium sulfate. Rijners, L. Experimental Evidence of Crystallization. Pressure inside Porous Media. Verran-Tissoires, M. Evaporation of sodium chloride solution from a saturated porous medium with efflorescence formation. Fluid Mech. Lavalle, J. Recherche sur la formation lente des cristaux. Sci Paris 36, — Becker, G. The linear force of growing crystals, Proc.
Washington Academy of Sciences 7, — CAS Google Scholar. Taber, S. The growth of crystal under external pressure. Correns, C. Growth and dissolution of crystals under linear pressure. Discussions of the Faraday Soc. A commented translation of the paper by C. Correns and W. Steinborn on crystallization pressure.
Weyl, P. Pressure solution and the of force crystallization: a phenomenological theory. Geophysical Res. Scherer, G. Crystallization in pores. Steiger, M.
Crystal growth in porous materials: I The crystallization pressure of large crystals. Stress from crystallization of salt in pores, Proceedings of 9 th international congress on deterioration and conservation of stone , Venice-Italy Coussy, O. Deformation and stress from in-pore drying-induced crystallization of salt.
Growth Des. Sekine, K. In situ observation of the crystallization pressure induced by halite crystal growth in a microfluidic channel. American Mineralogist. Royne, A. Rim formation on crystal faces growing in confinement. Hamilton, A. Direct measurement of salt mineral repulsion using atomic force microscopy. Bosworth, W. Strain-induced preferential dissolution of halite.
Metastability limit for the nucleation of NaCl crystals in confinement. Naillon, A. Evaporation with sodium chloride crystallization in capillary tube. Growth , 52—61 Shahidzadeh, N. Damage in porous media: role of the kinetics of salt re crystallization. EPJAP 60, De Gennes, P. Langmuir 24, — Errors in parallel-plate and cone-plate rheometer measurements due to sample underfill.
Meade, C. Yield strength of the B1 and B2 phases of NaCl. Winkler, E. Crystallization pressure of salt in stone and concrete. Geol Soc Am Bull 83, — Salt burst by hydration pressures in architectural stone in urban atmosphere. Geol Soc Am Bull 81, — Israelchvili, J. Intermolecular and surface forces [second edition] Academic Press Espinoza-Marzal, R. Hydrated ions ordering in electrical double layers. Veeramasuneni, S. Colloid Interface Sci. Interactions between dissimilar surfaces in high ionic strength solutions as determined by atomic force microscopy.
The surface charge of alkali halides: consideration of the partial hydration of surface lattice ions. Surface Science , — Alcantar, N. Force and ionic transport between mica surfaces: Implications for pressure solution.
Geochimica et Cosmochimica Acta 67, — Perkin, S. Dynamic properties of confined hydration layers. Farady discuss , — Siretanu, I. Direct observation of ionic structure at solid-liquid interfaces: a deep look into the Stern Layer. Scientific Reports 4, Dihson, M. From repulsion to attraction and back to repulsion: the effect of NaCl, KCl and CsCl on the force between silica surfaces in aqueous solution.
Du, H. Miller, J. Langmuir 8, — Hang, P. Methylene blue adsorption by clay minerals. Clays and Clay Minerals. Pavlik, Z. Construction and Building Materials. Wheeler, G. The widespread use of crystallization within industry is in part due to the fact that crystallization acts as both a separation and purification step; almost all chemical processes utilize at least one crystallization step either as key separation mechanism or final product engineering.
Development of crystallization processes represents a complex and challenging issue, requiring simultaneous control of various product properties, including purity, crystal size and shape, and molecular level solid structure. The control of the nucleation phase is difficult but is the key to process control; crystallization chemists usually aim to achieve goals of high purity and high yield by solely using controlled cooling crystallization techniques.
Depending on the conditions used, either nucleation or crystal growth may be predominant over the other, leading to crystals with different shapes and sizes. Therefore, controlling polymorphism is of significant interest in chemical manufacture.
A common example of the importance of crystal size can be found with ice-cream. Small ice crystals, formed through rapid cooling, improve the texture and taste of the ice-cream compared with larger ice crystals. Traditionally, crystal formation has been achieved by reducing the solubility of the solute in a saturated solution in a variety of ways.
Figure 2 shows that the given material is highly soluble in Solvent A, meaning more material can be crystallized from a given volume of solvent. Conversely, the given material has a low solubility in Solvent C across all temperatures, potentially making it a good anti-solvent for this material. As cooling continues, at a certain temperature, crystal nucleation will begin.
By carefully controlling the level of supersaturation of a solution, scientists can control the crystallization process. As can be seen from the above schematic, at low levels of supersaturation, crystals grow more quickly than they nucleate resulting in large crystal size distribution.
At high supersaturation levels, nucleation dominates crystal growth, providing smaller crystals. This makes understanding and controlling supersaturation vitally important when creating crystals of a desired size and distribution.
Crystallization is one of the most widely used technologies in chemical industry, and process robustness governs process productivity and economics.
In particular, the pharmaceutical and food sectors are utilizing crystallization for optimized separation, purification, and solid form selection. For example, crystallization is the most common method of formation of pharmaceutical solids for Active Pharmaceutical Ingredient API development. The optimization of the particulate properties such as particle size and shape distributions is paramount as the physical form dictates drug product quality and effectiveness.
Many pharmaceutical drugs have poor physiochemical profiles, such as poor solubility in biological fluids. Significant research and development efforts have been made towards developing a solid form landscape that covers all possible solid structures, including polymorphs, solvates, co-crystals, salts, and the amorphous phase to improve Active Pharmaceutical Ingredient API development.
For example, Sodium Chloride has been manufactured this way since the dawn of civilization. Various traditional methods for crystallization exist, with each technique having unique benefits and drawbacks.
The method chosen must be selected based on the properties of the material being crystallized.
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