Selective Extraction of Fe
Ions from Fe
with Phosphate Sorbents
I. L. Shashkova, N. V. Mil’vit, and A. I. Rat’ko
Institute of General and Inorganic Chemistry, National Academy of Sciences of Belarus, Minsk, Belarus
Received October 30, 2008
Abstract—The absorption of Fe
ions from Fe
mixture with zinc and calcium phosphates was studied.
INORGANIC SYNTHESIS AND INDUSTRIAL
ISSN 1070-4272, Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 6, pp. 956–962. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © I.L. Shashkova, N.V. Mil’vit, A.I. Rat’ko, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 6, pp. 901–907.
Presently, a variety of natural and synthetic
materials, from modified filings to most recent
synthetic ion-exchangers, products of complex organic
synthesis, has been proposed for recovery of
nonferrous metals from solutions. At the same time,
only few of them are selective. The extraction and
concentration of metal ions from solutions with
nonselective ion-exchangers or the use of chemical
precipitants (mainly, of hydroxides) results in the new
problems including burial or treatment of the obtained
concentrates and waste, which are necessary to remove
valuable nonferrous metals and recover them into
For processing of the solutions containing multiple-
charged ions, the chemisorption technologies using
heterogeneous chemical reactions with phosphates of
double-charged metal ions are promising [1, 2]. First,
the amount of heavy and nonferrous metals recovered
in the above processes is as high as 12 mmol g
exceeds by an order of magnitude the values for
common synthetic and natural ion-exchangers.
Second, the use of chemisorption procedures for
selective absorption of ions from mixtures has been
suggested and confirmed in practice of [3, 4]. It was
shown that selective chemisorption can be realized by
monitoring the ratio between the weight of
chemisorbent and the volume of a liquid phase. If in
the course of chemical reaction the sorbent may form
less soluble compounds with all cations, then all these
cations will be sorbed. In the case, when its mass is
insufficient, only a cation forming less soluble
compound with the sorbent will be sorbed.
This work continues the early study concerned with
the possibility of separating the Fe
with phosphate sorbents.
Double-substituted calcium phosphate CaHPO
O from Polilkhim Ltd Research and Production
Enterprise and zinc phosphate Zn
thesized by the method  were sorbents.
Sorption of metal ions from solutions of their
nitrate salts was studied under static conditions at room
temperature at varied ratio between the amounts of
sorbent and metal ions displaced into the solution.
Test solutions were prepared form crystal hydrates
of chemical purity grade Fe(NO
O and analytical
purity grade Zn(NO
O; 50 ml of a solution of
varied concentration was added to 0.2 g of the sorbent
(sifted fraction 0.075–0.125 mm), and this mixture was
kept for 1 day at intermittent stirring. Then, the solid
phase was filtered off and the concentration of metal
ions in the liquid phase was determined. The amount
of sorbed and released ions, the degree of metal
recovery from solution, and the molar ratios between
the amounts of sorbed ions and ions released into the
solution during heterogeneous reaction were calculated
from the difference of the concentrations of iron and
zinc ions in initial and equilibrium solutions after
The concentration of Fe
ions was measured
photocolorimetrically  on a KFK-2MP colorimeter.