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T. A. Graber

Bio: T. A. Graber is an academic researcher from University of Antofagasta. The author has contributed to research in topics: Supersaturation & Seed crystal. The author has an hindex of 2, co-authored 2 publications receiving 52 citations.

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TL;DR: In this article, the crystal growth of sodium nitrate and potassium nitrate from aqueous solutions, in a perfectly stirred batch crystallizer, has been studied considering the effect of temperature, supersaturation degree, and the size of seed crystal growth rate.
Abstract: In this paper, the crystal growth of sodium nitrate and potassium nitrate from aqueous solutions, in a perfectly stirred batch crystallizer, has been studied considering the effect of temperature, supersaturation degree, and the size of seed crystal growth rate. The mass transfer coefficients obtained correlated with Re, Sc and NL dimensionaless numbers. Supersaturation curve determination using a 0.5 mW He-Ne laser, connected to an automated data acquisition system, was the first stage of the study. The supersaturation and saturation curves were closely parallel with average DT value of 4.1 and 6.8 °C for KNO3 and NaNO3 respectively. For the growth kinetics order, unit values were found for both salts, with diffusion as a controlling stage.

29 citations

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TL;DR: In this article, a study was made on a isothermal process for the crystallization of potassium sulfate as an alternative to the cooling process, which employed addition of 1-propanol to aqueous salt solutions to achieve the salting-out of the K 2 SO 4.
Abstract: A study was made on a isothermal process for the crystallization of potassium sulfate as an alternative to the cooling process. The process employs addition of 1-propanol to aqueous salt solutions to achieve the salting-out of the K 2 SO 4 . This work was carried out using an automated Mettler Toledo model RC1 reactor-crystallizer with 800 ml capacity, and controlled isothermally at 25°C to test the crystallization of K 2 SO 4 by addition of the alcohol, and from 50 to 10°C for the cooling crystallization. In both systems, the line of nucleation points was shown to be approximately parallel to the saturation curve, with an average width of 13°C or 3 % mass for crystallization by cooling, compared with 0.2 to 1 % by salting-out. In experiments on crystallization by cooling, the K 2 SO 4 crystals were 0.27 mm in mean size, showed 7 % agglomeration, and contained 8.5 % moisture. Crystals obtained by salting-out had a mean size of 0.79 mm, 28 % agglomeration, and 9-10 % moisture content. A crystal shape factor of approximately of 0.7 was obtained in both systems, apart from the agglomeration.

25 citations


Cited by
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TL;DR: In this article, a semi-empirical approach based on the classical theory of three-dimensional nucleation combined with the formation of n-sized embryos from monomers according to the law of mass action is proposed.
Abstract: Experimental data on the maximum supercooling ΔTmax, a measure of metastable zone width, for solutions saturated at a temperature T0, as a function of cooling rate R are analyzed, for some solute−solvent systems chosen as examples, using Nývlt’s semiempirical approach and a new approach based on the classical theory of three-dimensional nucleation combined with the formation of n-sized embryos from monomers according to the law of mass action. Instead of a linear relation between ln(ΔTmax) and lnR of the Nývlt’s approach, the new approach predicts a linear dependence of (T0/ΔTmax)2 on lnR with slope F1 and intercept F. The quantity F1/F is independent of saturation temperature T0, characteristic of a solute−solvent and is associated with the growth of the stable three-dimensional nuclei to visible entities. The value of F1 is determined by thermodynamic and solvation processes, while that of F is governed by thermodynamic and kinetic parameters as well as processes associated with solvation of solute ions...

111 citations

Journal ArticleDOI
TL;DR: In this paper, a study of the nucleation kinetics for a cooling crystallisation of paracetamol-ethanol solutions in a batch reactor is described, and two theoretical approaches are employed to estimate the nucleations kinetics, the classical mass based approach of Nývlt, and a more recent approach by Kubota, which also considers number density.

101 citations

Journal ArticleDOI
TL;DR: In this article, a study of the nucleation kinetics for cooling crystallisation of paracetamol-ethanol solutions in a batch reactor is described, where induction time experiments were conducted in order to estimate the nucleations of the system.

64 citations

Journal ArticleDOI
Shijie Xu1, Jingkang Wang1, Keke Zhang1, Songgu Wu1, Shiyuan Liu1, Kangli Li1, Bo Yu1, Junbo Gong1 
TL;DR: In this article, a modified model based on the Sangwal's theory in which the nucleation parameters are not dependent on saturation temperature T 0 and nucleation temperature T 1 was proposed.

41 citations

Journal ArticleDOI
Wenli Zhang1, Yutao Hu1, Yun Wang1, Juan Han1, Liang Ni1, Yingchun Wu1 
TL;DR: In this article, the effect of poly(ethylene glycol) molecular weight on binodal curves was investigated, and it was found that the biphasic region expanded with an increase in PEG molecular weight.

40 citations