Conference paper

Methorics of Precipitation from Electrolytic Solutions as Revealed through Relationship between Concentrational Factors and Kinetics of Solid Phase Formation

B. Težak ; Laboratory of Physical Chemistry, Faculty of Science, University og Zagreb

Abstract

For an explanation of the pecularities of precipitating systems
they are treated as composed of five subsystems: (i) formation
of complex species (simple and monomers, as well as polynuclears
and polymers); (ii) embryonation (aggregates without core formation);
(iii) nucleation and direct growth (the growing core);
(iv) micellation (formation of primary particles with colloid
individuality); and (v) secondary structures of micro and macro
particles. It is assumed that the transition from ideal liquidus
structures (ILS) to ideal solidus structures (ISS) usually proceeds
through stages characterized by the development of methorical
structures and textures (MS & T).
Applying the method of continuous variation of concentration
of precipitating components the characteristic four types of
precipitation bodies (PB, as a plot of logarithm of concentration
of the cationic component against anionic one) are used for
description and discussion of experimental results.
For illustration some contours of PBs are given (silver
bromide; silver salts of fluoresceine group; uranyl phosphates;
iron-III hydroxides, thorium hydroxides, hydroxides of lanthanides,
all in aqueous solutions).
In discussing the morphology of the precipitates obtained
by »solution aging« or under the conditions of »homogeneous«
precipitation, it was pointed out that the phenomena may be
explained by taking into account the role of subsystems and the
discontinuities caused by aggregation of submicrons into larger
units.

Keywords

Hrčak ID:

197558

URI

https://hrcak.srce.hr/197558

Publication date:

20.8.1970.

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