Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 6, pp. 883−887.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © Yu.G. Khabarov, I.M. Babkin, V.A. Veshnyakov, 2012, published in Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 6, pp. 900−904.
AND INDUSTRIAL INORGANIC CHEMISTRY
Synthesis of a Magnetoactive Compound
Based on Iron(II) Sulfate
Yu. G. Khabarov, I. M. Babkin, and V. A. Veshnyakov
Lomonosov Northern (Arctic) Federal University, Arkhangelsk, Russia
Received May 27, 2011
Abstract—A method for synthesis of a magnetoactive compound based on iron(II) sulfate in the presence of ni-
trosated lignosulfonates at temperature of 20 to 50°C is suggested. The method yields a magnetoactive compound
with high relative magnetic susceptibility.
Magnetoactive compounds (MCs) whose particles
belong to nanosize objects with a unique combination of
ﬂ owability and ability to interact with a magnetic ﬁ eld
form the basis of magnetic ﬂ uids ﬁ rst obtained in the
1960s. The properties of MCs are determined by a set of
characteristics of the solid magnetic phase, dispersion
medium, and stabilizer, whose alteration enables a rather
wide variation of physicochemical parameters [1, 2].
Methods used to synthesize magnetic ﬂ uids can
be divided into two main groups: dispersion and
condensation. A magnetic ﬂ uid was ﬁ rst obtained by
Papell by wet mechanical dispersion of magnetite in
ball mills for 1000 h . R. Kaiser markedly accelerated
this process by using water and organic compounds as a
dispersion medium [4, 5].
At present, the main methods for synthesis of
magnetoactive compounds from separate molecules
are those employing condensation. Highly dispersed
magnetite is recovered from a solution of salts of di- and
trivalent iron [6, 7]:
+ 8 NaOH
↓ + 8 NaCl + 4H
The synthesis is performed at 70°C: to a mixture of
10% solutions of FeCl
O and FeCl
permanent vigorous agitation, an excess amount of
a 10% NaOH solution is added. For magnetite of the
required composition to be obtained, the Fe
ratio should be 2 : 1.
Precipitation of magnetite with a 25% ammonium
hydroxide solution [8–11] enables syntheses at 25–40°C.
J. Neal developed a method for synthesis of a water-
based magnetic ﬂ uid by chemical condensation with an
average size of magnetite particles of 10 nm [12, 13].
Magnetite particles are stabilized with a by-product
formed in sulfate cooking of cellulose, lignosulfonates
(LSTs). In most of other methods, that developed by
Neal, two salts of iron in different oxidation states
should be used. In addition, it is necessary to perform
a prolonged thermal treatment. The product obtained at
low temperatures is not magnetoactive.
V.G. Belikov and co-authors synthesized a magneto-
active compound from a single salt of iron(II) via a stage
of preliminary precipitation of iron(II) carbonate. In the
second stage of synthesis, performed at a temperature
of 55–60°C in the course of 1 h, iron(II) carbonate is
converted to magnetite, which is freed of impurities
by washing with distilled water to pH 7. The ﬁ nished
product is separated from the ﬂ uid by decantation .
A disadvantage of this method is in the low relative
magnetic susceptibility of the resulting MC.