ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 1, pp. 19!23. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + S.V. Antipov, M.T. Sokolov, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 1, pp. 20!24.
AND INDUSTRIAL INORGANIC CHEMISTRY
Mechanochemical Activation in Manufacture of Defluorinated
S. V. Antipov and M. T. Sokolov
Belarussian State Technological University, Minsk, Belarus
Received May 4, 2006
Abstract-The effect of preliminary mechanochemical activation of phosphate rock on the temperature of
hydrothermal calcination and degree of defluorination in manufacture of defluorinated forage phosphates
conforming to GOST (State Standard) 23 999380 was studied. A mechanism of mechanochemical activation
of phosphate raw materials, associated with changes in thermodynamic properties of the activated system,
Phosphorus is a structural element of a living body.
Its deficiency in rations weakens the resistance ability
of the living mass, impairs the milk productivity, and
disrupts the reproductive capacity. Phosphorus is
second to protein in importance for animal feeding.
At present, the overwhelming majority of methods
for processing of phosphorus-containing raw materials
are either energy-intensive (thermal), or require use of
inorganic (mostly sulfuric) acids, which leads to for-
mation of a difficultly utilizable waste, phosphogyp-
sum . A topical problem is that of development of
a simple power-saving technology for manufacture of
this product. A possible way to obtain forage phos-
phates could be a method based on acid-thermal proc-
essing of natural phosphates . This method consists
in that, prior to hydrothermal defluorination, natural
phosphate is treated with phosphoric acid. Such a
treatment leads both to an increase in the content of
the valuable component (P
) and to a deeper de-
fluorination. A significant disadvantage of this meth-
od is, in the authors’ opinion, the rather high defluori-
nation temperature (120031350oC).
Of particular recent practical and theoretical in-
terest is activation of chemical processes by mechano-
chemical activation [43 6]. The mechanochemical
activation consists in initiation and acceleration of
chemical transformations of reactants under a mech-
anical impact leading to deformation of the structure
of solid reagents . The plastic deformation of a
solid commonly not only changes its shape, but also
leads to accumulation of defects in the solid, which
changes its physicochemical properties, including
reactivity [5, 6].
The aim of our study was to examine the influence
exerted by mechanochemical activation of phosphate
raw materials on parameters of hydrothermal defluori-
nation in manufacture of defluorinated forage phos-
An analysis of the market of phosphate raw materi-
als from the standpoint of a Belarussian manufacturer
demonstrated that it is the most feasible either to use
phosphate rock from CIS countries (Kingisepp, Polpi-
no, Verkhnekamsk, Egor’evsk deposits) or to develop
deposits in Belarus (Mstislavl, Lobkovichi, Orekhov-
skoe, and Prigranichnoe deposits). The chemical com-
position of primary concentrates from some of these
deposits is listed in Table 1.
In the experiments, phosphate rocks from Polpino
and Kingisepp deposits were used as phosphorus-con-
taining raw materials. As activators served apparatus
of various types: dismembrator and vibrational, plane-
tary, and drum ball mills. The best results were ob-
tained with activators of planetary and drum types.
A ground phosphate rock was activated in a planetary
or drum mill for 53 60 min. The activated mixture was
treated with boiled-down (or not boiled-down) wet-
process phosphoric acid (WPA, nWPA) to a molar
= 2.5. The resulting plastic paste was
granulated by extrusion through dies with various die
aperture diameters. Weighed portions of humid grains
were subjected to hydrothermal calcination at 9003
1200oC. The results obtained in our study are listed
in Tables 2 and 3.