Note: Descriptions are shown in the official language in which they were submitted.
1~8343
This invention relates to a method for the manufacture
of a magnesium composite capable of generating hydrogen upon
introduction into water and to a method for the manufacture of
hydrogen by use of the composite manufactured by said method.
In recent years, hydrogen has come to attract in-
creasing attention as a prospective fuel. Hydrogen possesses
excellent properties as a fuel in that the combustion thereof
does not entail generation of air-polluting substances such as,
for example, sulfur oxides or nitrogen oxides. If a method is
established which permits easy and convenient generation of
hydrogen, then the hydrogen obtained by this method can be used
as an energy source in various fields, ranging from small-scale
household uses to heavy-duty industrial uses involving the
operation of automobiles, marine vessels, etc. For the manu-
facture of hydrogen, various methods have been developed and put
to commercial uses. A method which produces hydrogen by the
electrolysis of water, methods which produce hydrogen in the form
of a by-product in the modification of petroleum and coal gases
and in the electrolysis of common salt and other similar methods
are examples. However, these methods invariably require large-
scale manufacturing apparatuses.
It is universally known that when magnesium is allowed
to react with water, the reaction proceeds as indicated by the
following equation to generate hydrogen.
Mg + 2H2O -~ Mg(OH)2 + H2
In the above reaction, if magnesium prepared in the form of a
mixture with iron, nickel, copper, etc. or in the form of an
alloy with any of the metals described above is allowed to react
with water, then the forward reaction proceeds at an accelerated
rate. This is known to the art in view of, e.g., British Patent
. , q~
10"8343
No. 579,246 and U.S.P. No, 2,623,812.
An object of the invention is to provide a method for
producing magnesium composites useful for liberating hydrogen
from water.
According to one embodiment of the invention there is
provided a method for the manufacture of a magnesium composite
capable of generating hydrogen upon contact with water contain-
ing at least 1% by weight of a salt selected from the group
consisting of NaCQ, KCQ, Na2SO4, K2SO4 and mixtures thereof;
the method comprising placing magnesium and a metal powder
selected from the group consisting of chromium, iron, manganese,
nickel, zinc and oxides thereof in a container; applying
mechanical force to the magnesium and metal powder mixture
whereby 0.01~ to 30~ by weight of the metal powder is embedded
in the magnesium; and removing any excess of the metal powder
not embedded in the magnesium.
Firstly, a method for manufacturing a magnesium compo-
site having deposited on its surface at least one member selected
from the group consisting of iron, nickel, zinc, chromium and
manganese and prepared in the form of a metal powder or an
oxidized metal powder is described.
The form in which magnesium is used is not specifically
fixed. It can be used in the form of powder, granules, plates,
foils, etc. To meet requirements arising from practical con-
siderations, it may be used in the form of helically shaped
plates or foils or of cylindrically shaped rods, for example.
From the practical point of view, use of magnesium in the form
of plates having a thickness of not more than 1 mm results in
the formation of a magnesium composite which generates hydrogen
at an increased rate.
` ~V~8343
When magnesium is used in the form of powder or
granules, it is only natural that the particle diameter thereof
should be greater than that of the pure metal powder or oxidized
metal powder which is bein~ deposited thereon.
The metal powder or oxidized metal powder to be de-
posited on the magnesium desirably has a particle size not
coarser than 200 mesh as measured by the Tyler's standard sieves.
It is further desirable to include finer particles of the order
of 10 microns, for example.
Adhesion of such metal powders or oxidized metal powders
to the surface of the magnesium is accomplished by pressurized
friction. This adhesion by means of pressurized friction con-
stitutes one of the salient features of the present invention.
The term "pressurized friction" refers to an action whereby the
magnesium and the powder desired to be deposited thereon are
moved relative to each other while the two substances are held
pressed against each other. For example, the metal powder or
oxidized metal powder can be attached to the surface of the
magnesium, used in the form of granules, foils or plates, by
placing them both in a suitable container such as, for example,
a mortar and stirring the contents 30 to 100 turns with a pestle.
In this case, the amount of the metal powder or oxidized metal
powder to be attached to the surface of the magnesium is required
to fall in the range of from 0.01 to 30% by weiyht based on the
weight of magnesium. The required adhesion can be accomplished
by placing in the mortar the metal powder or oxidized metal pow-
der in an amount roughly 5 to 100 times in excess as is desired
to be attached to the magnesium and rotating the pestle in the
mortar as described above. When the magnesium used in this case
is in the form of foils or plates, the metal powder or oxidized
~(3198343
metal powder which has escaped adhesion to magnesium can be
recovered with extreme ease. When the magnesium is in the form
of granules, the removal of the metal powder or oxidized metal
powder can eas~ly be effected by any known technique for powder
separation, such as, for example, simple sifting or centrifu-
gation. The powder which has escaped adhesion and then is
recovered can be used in its unmodified form for the subsequent
cycle of magnesium adhesion.
The composite of magnesium and metal or metal oxide can
further be manufactured by placing the magnesium plate or foil
in the metal powder or metal oxide powder and moving the plate
or foil while applying pressure thereto.
The pressurized friction between the magnesium and the
powder can also be effected by placing the magnesium in the form
of foils or plates in a mass of the metal powder or oxidized
metal powder and beating the mass mildly, such as with a hammer,
for example, to afford the desired composite of magnesium and
metal powder or oxidized metal powder.
The aforementioned composite can otherwise be manu-
factured by a technique similar to the process employed for sur-
face polishing.
Magnesium is a metal which abounds in malleability and
exhibits a lower degree of hardness at normal room temperature
than iron, zinc, chromium and manganese. Thus, any of the treat-
ments described above permits the metal powder or oxidized metal
powder to be attached to the magnesium, giving rise to the
desired magnesium composite. The amount of the metal powder or
oxidized metal powder to be deposited on the surface of the
magnesium can be adjusted e.g. by suitably fixing the number of
revolu~ions of the pestle and the amount of powder placed in the
lOg8343
container or regulating the conditions of pressurized friction.
A microscopic observation of the magnesium composite
reveals that granules or particles of either the metal powder or
the oxidized metal powder are inserted into the recesses formed
on the surface of the magnesium matrix in conformity to the shape
of the granules or particles. The magnesium powder requires
careful handling so as to preclude the possibility of ignition.
When magnesium of a particle size coarser than lO0 mesh is
subjected to pressurized friction, however, no particular care
is required in its handling, except it is best treated in a dry
state.
The amount of the metal powder or oxidized metal powder
to be incorporated in the composite is selected with respect to
the purpose for which the produced hydrogen is used, with due
consideration being paid to the fact that this amount is
correlated to some extent with the rate at which hydrogen gen-
eration proceeds. It has been confirmed that the magnesium com-
posite is still effective when the amount of the metal powder or
oxidized metal powder incorporated therein is in the range of
0.01 - 2~ by weight based on the weight of magnesium. The com-
posite fails to produce the desired effect when the amount of
the metal powder or oxidized metal powder is lower than 0.01~
by weight and no increase of effect is gained when the amount
exceeds 30~ by weight. The fact that the magnesium composite is
effective even when the amount of the metal powder or oxidized
metal powder falls in the range of 0.01% - Q.1%, for example, by
weight based on the weight of magnesium as descrihed above has
been neither disclosed nor suggested anywhere in the literature
published to date.
When the magnesium aomposite is introduced into water
~.
10~8343
containing therein at least one member selected from the group
consisting of NaC~, KC~, Na2SO4 and K2SO4, hydrogen is generated.
As is demonstrated in the preferred embodiments and comparative
examples given herein below, the rate at which the generation of
hydrogen proceeds in this system is extremely high, as compared
with, a system in which a mixture of magnesium and a metal manu-
factured by the conventional method is introduced in water. If
impurities are present in the magnesium and in the iron, nickel,
zinc, chromium or manganese to be used in the manufacture of the
composite, they have no adverse effect upon the amount of hydro-
gen generated. River water, town water, sea water or any other
ordinary water can be used for the generation of hydrogen through
contact with the magnesium composite. In the case of sea water,
otherwise required addition of metal salts can be dispensed with,
for it contains NaCQ and other salts.
In the case of ordinary fresh water, the amount of NaCQ,
KCQ, Na2SO4 or K2SO4 to be incorporated is required to be not
less than 1% by weight.
A possible explanation for the enhanced generation of
hydrogen by the magnesium composite is as follows: The metal
powder or oxidized metal powder is uniformly attached in fine
particles to the entire surface of the magnesium metal. This
means that the area of contact between the powder particles and
the magnesium metal is extremely large. When this composite is
brought into contact with water to generate hydrogen, the pro-
portion of the surface of the magnesium covered by Mg(OH)2 is
small, so that no measurable decline of the activity of magnesium
is observed. This means that the generation of hydrogen con-
tinues.
The hydrogen which is generated by the method of this
invention has been assayed by gas chromatography to have a purity
6 --
"~ 10~ 3
exceeding 99.999%. Further, Mg(OH)2 produced in the reaction
can easily be converted into magnesium, which can be put to
cyclic use in the formation of magnesium composite.
As is clear from the foregoing description, the method
of this invention enables any ordinary water to generate hydro-
gen of high purity in large volumes at a high rate, indicating
that the present invention enjoys high practical value. When
the magnesium composite is manufactured in advance, hydrogen can
be obtained at virtually any place where ordinary water is
available. Thus, the present invention can be used in virtually
all fields requiring supply of hydrogen. Moreover, the magnesium
composite can be formed quite easily in any desired shape to
suit the purpose and use.
This invention will now be described with reference to
working examples and comparative examples which use iron, nickel
and chromium as typical metals for the formation of the magnesium
composite. The inventor has confirmed that use of manganese and
zinc brings about similarly desirable effects.
Example 1:
In a mortar, 8 g of magnesium 50 mesh and 4 g of iron
200 mesh were stirred 80 times with a pestle to produce a mixture
consisting of magnesium particles having iron powder attached
thereto and free iron powder. When this mixture was sieved to
separate therefrom the free iron powder which had escaped being
attached to the magnesium particles, there was obtained 8.012 g
of magnesium particles having 0.15% by weight of iron powder
attached to the surface thereof. The magnesium particles were
combined with 10 g of NaC~ and introduced into 1500 cc of city
water. Consequently, a total of 3600 cc (N.T.P.) of hydrogen
was generated within 20 minutes. The hydrogen thus yenerated
8343
was found to have purity of 99.999%.
Comparative Example l:
Exactly the same amounts of magnesium particles and
iron powder as used in Example l were placed in a container and
homogeneously blended by gently swirling the contents. The
resulting mixture was allowed to react with water under entirely
the same conditions as in Example l. In this case, a total of
40 cc (N.T.P.) of hydrogen was generated within 20 mir.utes.
It is seen from Example 1 and Comparative Example 1
that, when the admixture was effected in the absence of mechani-
cal pressure, the quantity of hydrogen generated was only one-
ninetieth of the quantity obtained when the admixture was made
in the presence of mechanical pressure. In Comparative Example
1, 4 g of iron powder i.e., 50% by weight based on the amount of
magnesium was used for the generation ~f hydrogen. The com-
parison shows that the magnesium composite according to this
invention had a pronounced effect.
Example 2:
A ribbon of magnesium measuring 0.3 cm in width, 0.02 cm
in thickness and 12.96 cm in length and weighing 0.14439 g was
placed in a mortar containing 5 g of iron and stirred 50 times
with a pestle. The ribbon of magnesium was then weighed. The
weighing showed that 0.000119 g of iron powder had been attached
to the ribbon surface. Calculation shows that the amount of iron
powder thus attached was about 0.08% by weight.
When this composite ribbon of magnesium was thrown in
400 cc of water containing lO g of NaCQ, there ensued vigorous
generation of hydrogen which lasted for 50 minutes. The rate of
hydrogen generation was 4.35 cc/min (N~T.P.~. The purity of the
hydrogen was found to be 99.999%.
~og8343
Comparative Example 2:
Under exactly the same conditions as in Example 2, a
mixture of 0.14439 g of magnesium particles 50 mesh with
0.00011 g of iron powder (200 mesh) was processed and then
tested. In this case, the quantity of hydrogen generated in
30 minutes was 0.7 cc (N.T.P.).
It is seen from Example 2 and Comparative Example 2
that the composite ribbon of magnesium according to this inven-
tion was more effective.
Similar results were obtained when the procedure was
repeated by using Na2SO4 or K2SO4 in place of NaCQ.
Example 3:
A ribbon of magnesium measuring 3.1 mm in width, 0.2 mm
in thickness and 474 mm in length, weighing 0.5321 g and having a
purity of 99.9% was placed on an iron plate having scattered
thereon 50 g of iron powder having a particle size not larger
than 300 mesh. By rolling a cylinder of steel plate 3.5 cm in
diameter and 30 cm in length so as to press the ribbon lightly,
the iron powder adhered to the ribbon of magnesium. The amount
of iron powder thus attached was 0.0051 g. When the ribbon of
magnesium having the iron powder attached thereto was immersed
in 1000 cc of sea water, generation of hydrogen followed. The
relation between the cumulative volume of hydrogen generated and
the length of time of the ribbon's immersion in the sea water is
shown below:
Time (minute) 5 10 15 20 25 30
Cumulative volume 70 135 185 232 272 304
(cc) of hydrogen
This rate of hydrogen generation is unusually large as
compared with that obtainable with the known method.
~0~8343
Example 4:
A ribbon of magnesium measuring 3 mm in width, 0.2 mm
in thickness and 475 mm in length, weighing 0.5339 g and having
a purity of 99~ was placed in ferric oxide powder. The ribbon
of magnesium was moved around in the powder by virtue of strong
pressure applied thereto with a cylinder of steel plate 3.5 cm
in diameter and 30 cm in length. Consequently, 0.0002 g of the
ferric oxide powder adhered to the ribbon of magnesium. When
the ribbon of magnesium having the ferric oxide powder attached
thereto was immersed in 1000 cc of sea water, hydrogen was gen-
erated as follows:
Length of time (min) 10 20 30 40 50 60 70 80
Cumulative volume 85 165 228 298 357 404 438 465
This rate of hydrogen generation is unusually large as
compared with that obtainable with the known method.
Example 5:
A ribbon of magnesium measuring 0.3 cm in width, 0.02 cm
in thickness and 13.1 cm in length and weighing 0.14705 g and
10 g of nickel powder having a maximum particle size of 200 mesh
were placed in a mortar and were stirred by revolving a pestle
about 60 times inside themortar to effect pressurized friction
thereof. Consequently, 0.00092 g of nickel powder was deposited
onto the ribbon of magnesium. When the magnesium composite thus
obtained was introduced into 400 cc of sea water, hydrogen was
generated vigourously. This generation of hydrogen lasted for
45 minutes. The rate of hydrogen generation was 4.37 cc~minute
(N.T.P.).
Example 6:
A ribbon of magnesium measuring 0.3 cm in width, 0.0~ cm
-- 10 --
~. ,
lOg8343
in thickness and 12.56 cm in length and weighing 0~13285 g and
10 g of chromium powder having a maximum particle size of 200
mesh were placed on an iron plate. A cylindrical iron bar
measuring 3.5 cm in diameter and 30 cm in length was rolled on
its side over the iron plate to move the ribbon of magnesium
relative to the metal powder and consequently effect pressurized
fricton. Thus there was obtained a magnesium composite having
0.00121 g of chromium powder deposited thereon. When this
composite was placed in 400 cc of tap water having 10 g of NaCQ
dissolved in advance therein, hydrogen was generated vigorously.
This hydrogen generation lasted for 70 minutes. The average rate
of hydrogen generation was 3.85 cc/minute (N.T.P.).
-- 11 --
