Potassium chloride crystallization

INTRODUCTION This data sheet summarizes properties of single crystal potassium chloride. 

A furtlier problem is tire influence of tire ratlier unusual—from tire physiological viewpoint—salt conditions necessary for crystallization. It should not be presumed tliat proteins embedded in a crystal are in tlieir most common native stmcture. It is well known tliat, witli tire exception of sodium or potassium chloride, which are not very useful for inducing crystallization, salts change key protein parameters such as tire melting temperature [19]. 

Longer-chain amines, ie, arachidyl—behenyl (C2Q to C22) amines, are used ia special cases ia which brine temperatures exceed 35°C. At temperatures higher than ambient, normal tallow amine tends to dissolve and therefore is unavailable to coat the surfaces of the potassium chloride crystals. Amine consumption is from 50 g/1 (ca 40 wt % KCl) of high grade ore, to 150 g/1 (ca 20 wt % KCl) of low grade ore. 

Salt Substitutes. As a result of concern about the relationship between dietary sodium and hypertension, some salt producers and food companies have developed salt substitutes or low sodium products. Mixtures of sodium chloride and potassium chloride, herbs and spices, as well as modified salt crystals of lower density are marketed in response to a limited consumer demand for reduced-sodium products. This amounts to about 2% of user salt purchases. 

Recovery Process. Boron values are recovered from brine of Seades Lake by North American Chemicals Corp. In one process the brine is heated to remove some water and burkeite. The remaining brine is cooled to remove potassium chloride. This cooled brine is then transferred to another crystallizer where borax pentahydrate, Na2B40y 5H20, precipitates (18). In a separate process, boron is removed by Hquid—Hquid extraction followed by stripping with dilute sulfuric acid (19). Evaporator-crystallizers are used to recover boric acid [10043-35-3] H BO. In a third process, borax is recovered by refrigerating a carbonated brine. 

E. C. Pendery, inj. L. Rau and L. E. DeUwig, eds., "Potassium Chloride Crystallization," Third Symposium on Salh Vol. II, Northern Ohio Geological Society, Cleveland, Ohio, 1970, pp. 211—218. 

Potassium and ammonium dichromates are generally made from sodium dichromate by a crystallization process involving equivalent amounts of potassium chloride or ammonium sulfate. In each case the solubiHty relationships are favorable so that the desired dichromate can be separated on cooling, whereas the sodium chloride or sulfate crystallizes out on boiling. For certain uses, ammonium dichromate, which is low in alkaH salts, is required. This special salt may be prepared by the addition of ammonia to an aqueous solution of chromic acid. Ammonium dichromate must be dried with care, because decomposition starts at 185°C and becomes violent and self-sustaining at slightly higher temperatures. 

Another method of fractional crystallization, in which advantage is taken of different ciystallization rates, is sometimes used. Thus, a solution saturated with borax and potassium chloride will, in the absence of borax seed ciystals, precipitate only potassium chloride on rapid coohng. The borax remains behind as a supersaturated solution, and the potassium chloride crystals can be removed before the slower borax crystalhzation starts. 

Potassium chloride is crystallized from sea bitterns containing chlorides of potassium, sodium and calcium by ammoniation (Jagadesh etai, 1992). This process is less energy intensive and more efficient than by fractional crystallization by evaporation, as the ammonia used is recovered by distillation. Crystallization produces a better quality product in terms of both size and purity than by other methods. 

Aoki, Y. and Nakamuto, Y., 1984. Penetration twins of potassium chloride. Journal of Crystal Growth, 67, 579-586. 

Qian, R., Chen, Z., Ni, H., Fan, Z. and Cai, F., 1987. Crystallization kinetics of potassium chloride from brine and scale-up criterion. American Institution of Chemical Engineers Journal, 33, 1690-1697. 

If potassium chlorate, KCIO is heated gently, the crystals will melt. Further heating will decompose it to give oxygen gas and potassium chloride, KC1. 

Circulating magma Production of large-sized crystals. High throughputs Ammonium and other inorganic salts, sodium and potassium chlorides... 

Some tablets combine sustained-release and rapid disintegration characteristics. Products such as K-Dur (Key Pharmaceuticals) combine coated potassium chloride crystals in a rapidly releasing tablet. In this particular instance, the crystals are coated with ethylcellulose, a water-insoluble polymer, and are then incorporated into a rapidly disintegrating microcrystalline cellulose (MCC) matrix. The purpose of this tablet is to minimize GI ulceration, commonly encountered by patients treated with potassium chloride. This simple but elegant formulation is an example of a solid dosage form strategy used to achieve clinical goals. 

BFR [Bleach filtrate recycle] A process for almost completely recycling the waste liquors from pulp-bleaching using chlorine dioxide. The key to the process is the separation of the sodium sulfate from potassium chloride by crystallization. Developed by Champion International Corporation, Sterling Pulp Chemicals, and Wheelabrator Technologies. It was proposed for installation in North Carolina in 1997. 

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