Crystallization of potassium chloride: The additives ZnCl₂, Na₆ [(PO₃)₆] and K₄ [Fe(CN)₆]

Abstract

The batch crystallization of potassium chloride from aqueous solution is investigated without impurities, with zinc chloride I (30, 100, 1000 ppm), with sodium hexanietaphosphate I1 (100 ppm) and potassium hexacyanoferrate (11) I11 (1 00, 500, 1000, 16 x 25 ppm). The dominant particle size of the pure system LN,D = 427 V r n increases by 4040 by addition of I and by 250% by addition of 11. While I does not affect the habit I1 changes it from cubes to octahedrons. In cases of low concentration, 111 leads to dendrites.It is shown that addition of 111 decelerates growth and increases the metastable zone width. Hence a high supersaturation is formed, the solution impoverishes fast while 111 gets incorporated and therefore a strong nucleation starts in a relatively pure solution. By quasi-continuously adding 16 x 25 ppm of 111 the dominant particle size increases by 160% with little fines. In this case the content of 111 in the product is relatively low.

Morphological control of Ca3Al2(OH)12

“…For example, the growth of KCl in the presence of sodium hexametaphosphate leads to the formation of octahedral crystals ({111} face) rather than the usual cubic morphology ({100} face). [6] In many cases the crystal growth modifier leads to the observation of more complex morphologies that do not simply consist of a combination of crystal faces. One material that has been shown to be particularly flexible in the morphologies adopted is CaCO 3 .…”

Incorporation of Cyano Transition Metal Complexes in KCl Crystals—Experimental and Computational Studies

“…Incorporation of cyano complexes into potassium chloride has been reported previously with an emphasis on spectroscopic characterization of the complex, [8][9][10][11][12] and the effect of hexacyanoferrate(ii/iii) on the morphology of sodium chloride is well known with the iron(iii) complex inducing a change from cubic to octahedral, and the iron(ii) complex causing dendritic growth. [4] It is interesting to note that in the present work, cubic crystals were produced in all cases. This may be a result of growing crystals by temperature reduction rather than evaporation; * this observation requires further investigation but lies outside the scope of the work presented here.…”

“…In the production of salt by evaporation of saline water, hexacyanoferrate(ii) is added to prevent caking. [4] In the photographic industry, transition metal complexes are incorporated into the silver halide microcrystals that comprise photographic emulsions, which mediate the formation of the latent image. [5] Computer simulations of impurity incorporation in crystals should result in improved understanding of the crystal-additive interactions.…”

Machine Learning Methods to Improve Crystallization through the Prediction of Solute–Solvent Interactions

“…Crystallization is a pivotal process in sectors such as pharmaceutical, food and beverage, and chemical production, playing a critical role in defining the quality and characteristics of a wide range of products. This process is fundamental in creating crystalline products that span a diverse array of applications, including bulk chemicals like sodium chloride and sucrose, essential in everyday life, and crucial agricultural fertilizers such as ammonium nitrate [1], potassium chloride [2], ammonium phosphates [3] and urea [4]. In the pharmaceutical industry, crystallization is vital for producing valuable products such as active pharmaceutical ingredients [5] and organic fine chemicals [6], where the purity and morphology of crystals can significantly impact drug efficacy and safety.…”