ISSN 0036-0236, Russian Journal of Inorganic Chemistry, 2006, Vol. 51, No. 9, pp. 1349–1354. © Pleiades Publishing, Inc., 2006.
Original Russian Text © V.D. Sasnovskaya, A.P. Razumova, 2006, published in Zhurnal Neorganicheskoi Khimii, 2006, Vol. 51, No. 9, pp. 1439–1444.
SYNTHESIS AND PROPERTIES
OF INORGANIC COMPOUNDS
Oxidation of Magnesium in the Systems NaClO –Mg–Metal
4
Oxide (Peroxide)
V. D. Sasnovskaya and A. P. Razumova
Institute of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow oblast, 142432 Russia
Received October 20, 2005
Abstract—Oxidation of magnesium in mixtures NaClO + Mg + metal oxide or peroxide has been investigated
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using differential thermal analysis (DTA). In the systems with peroxides Na O , Li O , BaO , CaO or ZnO,
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2
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magnesium oxidizes simultaneously with decomposition of NaClO in the region 380–520°C, which is 100–
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00°C below the oxidation temperature of magnesium in air. In the ternary systems with transition-metal oxides
NiO, CuO, FeO, and Fe O , magnesium transforms into oxide at above 600°C after sodium perchlorate had
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been decomposed completely. The low-temperature oxidation of magnesium occurs in the systems in which
sodium chlorate is accumulated during the catalytic decomposition of NaClO4.
DOI: 10.1134/S0036023606090038
Magnesium is used as a fuel in solid fuel oxygen centration conditions with simultaneous proceeding of
generators to maintain the self-propagating generation all chemical transformations.
of oxygen during thermal decomposition of the oxygen
In this work, the behavior of the NaClO –metal
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carrier [1]. As a rule, the fire point of magnesium in
oxide (or peroxide) magnesium systems is investigated
oxygen ((635 ± 5)°C [2]) is above the decomposition
under heating, and the effects of Li O , Na O , MgO,
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temperature range of the oxygen carrier. For NaClO4
this range is 485–580°C.
CaO, CaO , BaO , ZnO, NiO, CuO, FeO, and Fe O on
magnesium oxidation in these systems is investigated.
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Magnesium oxidizes rapidly during intense oxidant
decomposition only if the oxidant decomposition tem-
perature is higher than >600°C, as in the case of KClO4
EXPERIMENTAL
[
3]. If the decomposition temperature of the oxidant is
Sodium perchlorate NaClO4 (pure grade) was
recrystallized from an aqueous solution and dehydrated
in a rotary evaporator at 300°C. The starting sodium
below 600°ë, magnesium oxidizes only partially dur-
ing oxygen generation, which is observed in the system
containing LiClO [4]. Magnesium behaves similarly
in the binary systems with sodium chlorate or sodium
perchlorate [5]. The investigation of the KClO –Mg
system [6] showed that the degree of magnesium oxida-
tion during decomposition of KClO in the range
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chlorate NaClO (pure grade) was twice recrystallized
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from an aqueous solution and dried at 110°C under
atmospheric pressure. We also used a PMF-4 magne-
sium powder of dispersity ~50 µm. Metal oxides and
peroxides, namely, Na O (96% pure), Li O (high-
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56−540°C is no higher than 7%. The main reaction of
purity grade), LJé (analytical grade, 85 wt % purity),
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magnesium with oxygen proceeds at about ~ 600°C
after the oxygen carrier has already been decomposed
completely. To use magnesium as a fuel in these sys-
tems efficiently, it is necessary to determine the condi-
tions under which metal oxidation and decomposition
of the oxygen carrier proceed in the same temperature
MgO (analytical grade, host content 97 wt %), CuO
(
pure grade), ZnO (reagent grade), FeO (pure grade),
Fe O (analytical grade), and NiO (os.-ch. 10-2 grade)
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were used without purification. Calcium peroxide
ë‡é (96% purity) was prepared by the method
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range. This will simultaneously provide a decrease in described in [8]. Calcium oxide CaO was prepared by
the combustion temperature of the solid oxygen source. decomposing ë‡é at 500°C.
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We previously found that, in the system with sodium
The thermoanalytical investigation of the samples of
chlorate and calcium peroxide or calcium oxide, mag- weight 0.1–0.2 g, which were prepared by mixing the
nesium transforms into magnesium oxide completely at components in an agate mortar, was carried out in alun-
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60–460°C [7]. The low-temperature oxidation of the dum crucibles using a Derivatograph 1500D thermal
metal proceeds in this ternary system under certain con- analyzer at a heating rate of 10 K/min. In solid decom-
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