Influence of the Composition and Structure
of α-Alkyldicarboxylic Acids on the Mineral Surface
Hydrophobization under Flotation Conditions
V. A. Ivanova and G. V. Mitrofanova
Mining Institute, Kola Scientific Center, Russian Academy of Sciences, Apatity, Murmansk oblast, Russia
Received November 27, 2008
Abstract—The hydrophobization effect of α-alkyldicarboxylic acids in microflotation of pure apatite variety
was examined in relation to the alkyl radical length, the total length of the hydrocarbon chain and the positional
relationships of the carboxy groups in the molecule, and the presence of calcium cations in the liquid phase of
suspension. These findings were compared with the analogous data for saturated monocarboxylic acids and
unsaturated oleic acid.
AND CORROSION PROTECTION OF METALS
ISSN 1070-4272, Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 9, pp. 1515–1521. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © V.A. Ivanova, G.V. Mitrofanova, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 9, pp. 1419–1424.
Our previous studies [1, 2] demonstrated that α-
alkyldicarboxylic acids (DAs) with a total of 14–21
carbon atoms in the hydrocarbon chain are suitable as
collecting reagents for flotation of apatite- and kyanite-
containing ores. At the same time, it was shown that
the collecting power of the DAs widely varies with the
composition and structure of their molecules, pH, and
ionic composition of the liquid phase of the flotation
pulp, in particular, depending on the presence of
calcium ions in it. These features of the flotation
behavior of DAs are associated with variation in their
physicochemical and surface properties, manifested
both in the bulk of the liquid phase and at the water–air
and water–mineral particle interfaces, and call for
We studied earlier the surface activity of Na and Ca
salts of the examined DAs at the water–air interface
and their micellization ability in alkaline aqueous
solutions . It was found that these properties are
decided by the alkyl radical length, position of the
second carboxy group in the hydrocarbon chain of the
DA, and the associated ability for forming calcium
compounds with various structures.
Here, we elucidated the trends in the hydro-
phobization effect exerted by DAs with various
compositions on the mineral particle surface as
manifested under flotation conditions. This will allow
the substantiation of the choice of DAs with the
structures best suited for the collector application and
identifying their efficient application spheres.
The surface activity of branched dicarboxylic acids
at the solution–mineral particle interface was studied
with the synthesized α-alkyldicarboxylic acids of the
where R is the alkyl radical, from C
– to C
and m = 1–11 (see the table). For characteristics of
these acids, see .
The surface activity of the acids was assessed from
their hydrophobization effect on the monomineral
fraction of apatite with the particle size from –0.16 to
+0.1 mm, determined by the yield of the mineral in
foamless flotation in the Hallimond tube.
Flotation conditions: apatite weighed portion 0.5 g;
suspension volume 100 ml; air flow rate 5.3 ml min
pH adjuster H
, NaOH; time of agitation with pH
adjuster 1 min; time of agitation with collector 3 min;
flotation time 3 min; flotation temperature 20 ±1°C.