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Interpretation of crystallization induction periods

1988; Elsevier BV; Volume: 123; Issue: 1 Linguagem: Inglês

10.1016/0021-9797(88)90219-6

1095-7103

O. Söhnel, J.W. Mullin,

Spectroscopy and Quantum Chemical Studies

The crystallization induction period tind, is interpreted as the sum of the time for critical nucleus formation, tn, and growth to detectable size, tg. Expressions describing the dependence of tind on supersaturation are derived for the cases tn ⪢ tg, tn ≈ tg, and tn ⪡ tg, taking into account different possible nucleation and growth mechanisms, and their validity is assessed on the basis of experimental evidence. From the dependence of the induction period on solution supersaturation it is possible to deduce whether the new phase appearance is governed either by nucleation (or nucleation followed by growth) or by growth alone. In specific cases the dependence can also reveal the controlling mechanisms of nucleation and/or growth. Non-steady-state nucleation is not significant in the precipitation of inorganic electrolytes from aqueous solutions, except in special cases.