著者

HARANO YOSHIO OOTA KOICHI

出版者

The Society of Chemical Engineers, Japan

雑誌

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN (ISSN:00219592)

巻号頁・発行日

vol.11, no.2, pp.119-124, 1978

被引用文献数

2

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Heat evolution rate curves were recorded with KBrO₃-quiet supersaturated aqueous solution at constant cooling temperature, <i>T</i>, by using a differential scanning calorimeter and were analyzed on the basis of the growth rate of all crystallites pre-formed in the sample solution. Taking microscopic observation into account, the expression of the overall growth rate, <i>R</i>, was derived, on the assumption that the crystallite surface is Kossel''s and that its growth rate is determined by two-dimensional nucleation rate, <i>J''=k₁''S^m''</i>.<br> <i>R=βhAJ''≈k₁"(C₀-C)^2/3S^m''</i> (1)<br>where C, C₀ and S are concentration at <i>t=t</i> and =0 and supersaturation ratio, respectively. <i>m''</i> is number of solute in a critical nucleus and is not constant, but depends on <i>S</i> and <i>T</i>.<br> The values of two-dimensional nucleation parameters (<i>m''</i> radius, free edge energy σ'' and surface energy estimated from σ'' and activation energy) were of reasonable order of magnitude. Comparison of these values with those of the three-dimensional parameters obtained previously is discussed. It may be concluded that Eq. (1) and hence the expression for <i>J''</i> proposed in this paper are adequate for the growth rate and two-dimensional nucleation rate, respectively.