Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 11, pp. 1786−1789.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © L.V. D’yakova, A.G. Kasikov, G. I. Kadyrova, 2012, published in Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 11, pp. 1884−1887.
An Effect of Nature and Concentration of a Modiﬁ er
on Extraction of Cobalt(II) from Chloride
Solutions by Trioctylamine
L. V. D’yakova, A. G. Kasikov, and G. I. Kadyrova
Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials, Russian Academy of Sciences,
Kola Science Center, Apatity, Russia
Received December 20, 2012
Abstract—An effect of modiﬁ ers on extraction of cobalt from chloride solutions was studied in an extraction
mixture with trioctylamine. An optimal range of concentration of the most active modiﬁ er, actanone-2, was up
to 50%. Excess concentrations of octanone-2 led to structural changes and reduced ketone extraction of cobalt.
Removing non-ferrous metals from multicomponent
solutions is an important task of hydrometallurgy and
a liquid extraction plays a key role in its solving .
Tertiary amines are of great importance among the large
number of non-ferrous metal extractants (organophos-
phorus and carboxylic acids, amines, ketones) due to
wide possibilities of these extractants for extraction and
puriﬁ cation of metal salts in chloride solutions [2–4].
However, a high viscosity and limited solubility of amine
salts involves the use of modiﬁ ers, among which mac-
romolecular aliphatic alcohols are of the most practical
application, in particular, to extract cobalt. Analysis of
the literature and previous results shows that in the case
of alcohol application in addition to improving the hy-
drodynamic characteristics of the process a suppression
of the extraction of metal complexes is observed due to
formation of stable solvates with amine salts [5, 6].
For selecting an optimal composition of extraction
mixture we studied compounds, which can be used as
modiﬁ ers of the tertiary amines in the extraction of cobalt
and its puriﬁ cation from impurities in chloride solutions.
The goal of the study is examining the effect of
a modiﬁ er nature and amount in an extraction mixture
with amine on a performance of cobalt recovery from
To prepare the extraction mixtures trioctylamine
(TOA), monounsaturated oleic acid, octyl alcohol
(octanol-1), and aliphatic ketones: methyl isobutyl ketone
(MIBK) and methyl hexyl ketone (octanone-2), were
used. Their calculated amounts were mixed in an inert
Eskeide diluent. The mixture was transformed into the
chloride form by contacting with 8 M HCl, the excess
acid was washed with water. Initial aqueous solutions
of cobalt chloride was prepared by dissolving CoCl
(chemically pure) in water followed by adjusting the
pH to the desired value using HCl. Experiments on the
extraction and stripping were carried out in test tubes with
ground stoppers at 20.0 ± 0.5°C, which was sufﬁ cient to
establish equilibrium, and contact of phases for 5 minutes.
Cobalt in aqueous solutions was determined by an atomic
absorption spectrometry (AAS), the metal concentration
in the organic phase was calculated by the difference
between the content in the original solution and rafﬁ nate
and also based on the analysis of solutions after deep
stripping the organic phase. IR spectra were recorded on
a spectrophotometer Specord M-80 in thin ﬁ lms between
KBr windows in a range of 3800–400 cm
On testing different organic reagents as modiﬁ ers we
found that ketones and fatty acids possess higher solubi-