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Supersaturation and Crystallization

At supersaturation the chemical potential of the solution and that of the solid that is formed on crystallization are equal  [Pg.22]


In both sexes, CCM-OJ provided an alkali load that significantly increased urinary pH compared to basal levels and versus milk consumption, and also increased urinary citrate excretion versus basal levels. An elevated urine pH and citrate level are generally considered to reduce Ca oxalate supersaturation and crystallization potential (Odvina, 2006). However, in this study the relative supersaturation measurement for Ca oxalate was not different between the CCM-OJ and milk treatment groups, or between either treatment and the basal levels. Although the alkalizing effect of milk was less than that of CCM-OJ, it also induced a higher urinary pH compared to basal levels (p <. 01 and p <. 05 in women and men, respectively). [Pg.308]

In the absence of nuclei and agitation, solutions of lactose are capable of being highly supersaturated before spontaneous crystallization occurs. Even in such solutions, crystallization occurs with difficulty. Solubility curves for lactose are shown in Figure 2.6 and are divided into unsaturated, metastable and labile zones. Cooling a saturated solution or continued concentration beyond the saturation point, leads to supersaturation and produces a metastable area where crystallization does not occur readily. At higher levels of supersaturation, a labile area is observed where crystallization occurs readily. The pertinent points regarding supersaturation and crystallization are ... [Pg.40]

J.A.H. van Laarhoven, M.A.B. Kruft, and H. Vromans, Effect of supersaturation and crystallization phenomena on the release properties of a controlled release device based on eva copolymer, J. Controlled Release, 82(2-3) 309-317, August 2002. [Pg.209]

It may happen that the hot solution remains supersaturated, and crystallization does not take place, until the solution is cooled. The checkers obtained a poor yield when this occurred. They, therefore, seeded other runs during the boiling process in order to bring about crystallization. Posner1 had to concentrate the solution to about half its volume in order to bring about crystallization. [Pg.74]

Reichle etal (11), have observed a decrease of surface area from about 120 m for hydrotalcite crystallized at 333 K to 13.9 mV for hydrothermally treated sample. X-ray data of HTl and HT2 are in agreement with their observation. However, the surface area was found to decrease only by half for the hydrothermally treated sample HT2. The hydrothermally treated sample has a surface area of 32 mV The low surface area may be due to a large crystallite size of the hydrotalcite. Surface area of the hydrotalcite prepared at high supersaturation and crystallized at 333 K is 60 mV The surface area was found to be same for the catalysts with different Mg/A Iratio supports. The support with interlayer S04 ion has only 5 mV surface area. [Pg.361]

The driving force for crystallization, the supersaturation, is composed of two zones, the metastable and unstable zones (Figure 7.1). The solid line in Figure 7.1 represents a saturation or solubility curve (S), while the dashed line corresponds to the supersolubility or supersaturation curve (SS). Below S, crystallization is impossible. Above S, in the metastable zone, the system is supersaturated and crystallization is possible with the aid of agitation or seeding. On the other hand, in the unstable region, crystallization is spontaneous and crystals appear after nucleation... [Pg.222]

The reaction need not be limited to liquid and gases, as shown in Figure 5.14. In Figure 5.15, for example, an ore is dissolved (decomposed) in mother liquor with the resultant supersaturation and crystallization of another crystalline material. Materials may also be precipitated by common-ion effect or by salting out through the addition of solutions or other solids. These techniques are important because they frequently reduce energy consumption. [Pg.130]

Mullin, J.W. and Ang, H-M. (1977) Supersaturation and crystal size distribution changes during the precipitation of nickel ammonium sulphate hexahydrate. Kristall und Technik, 12, 105-115. [Pg.560]

Ting, H.H. and McCabe, W.L. (1934) Supersaturation and crystal formation in seeded solutions of MgS04. Industrial Engineering Chemistry, 26, 1201-1207. [Pg.571]

Figure 3.3.6B. Concentration vs. temperature behavior for saturation, supersaturation and crystallization. Figure 3.3.6B. Concentration vs. temperature behavior for saturation, supersaturation and crystallization.

See other pages where Supersaturation and Crystallization is mentioned: [Pg.13]    [Pg.35]    [Pg.303]    [Pg.9]    [Pg.41]    [Pg.58]    [Pg.155]    [Pg.742]    [Pg.22]    [Pg.23]    [Pg.494]    [Pg.509]    [Pg.460]    [Pg.1055]   


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