Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to absorbing substances for the
removal of catalyst poisoning gases, viæ. the compounds of hydrogen with the
elements of Group V of the Periodic Table of Elements, particularly with
arsenic (As) and antimony (Sb), from the oxyhydrogen mixtures ~hich are gen-
erated during the operation of lead-acid storage batteries. The invention
~urther relates to methods of producing such absorbing substances, and to
the application of such substances in combination with a special catalyst
unit taking the place of 8 closure plug on a lead-acid storage bsttery, the
purpose oP thi6 catalyst unit being to catalytically recombine the hydrogen
and oxygen gases generated during the operation Or the lead-acid storage
battery to obtain water which i8 returned to the battery electrolyte.
It iB known that considerable problems still exist in connection
; with the catalytic recombination of hydrogen and oxygen produced by lead-
~.
~` acid 6torage batteries, as a result of the poisoning of the activ~ cataly6t
material through the gaseous compounds of antimony-hydrogen and arsenic-
hydrogen, the so-called catalyst poisoning gases. These catalyst poisoning
gases are produced through the reaction of hydrogen with certain alloy com- -
ponents of the lead used in the manufacture of lead-acid storage batteries.
Primarily for reason6 of improved quality, the lead alloy6 used for a wiae
variety of lead-acid storage cells frequently contain arsenic and antimony
components. These alloy components combine with hydrogen to form the
volatile, rather unstable, gaseou6 compounds of antimony hydride (SbH3) and
arsenic bYdride (AsH3), both being very effective as cataly~t poisoning
gases~
It has been variously attempted in the past to remove these so-
j~ called catalyst poisoning gases from the oxyhydrogen gas mixtures which are
generated by electrical lead-acid storage batteries. For instance, one
approach (United States Patent No. 3,102,059) suggests that the oxyhydrogen
gases, before reaching the catalyst, are made to flow over a granular bed of
alumina or of a mixture of alumina and lead-dioxide on an alumina carrier.
It is further known (United States Patent No. 3,038,954) to arrange a bed of
lead-oxide on a carrier of P-luminum-oxide powder inside a battery plug in the
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~low path of the gases ahead o~ the catalytic material which
recombines the hydrogen and oxygen generated by the battery.
A particular shortcoming of these prior art substances is
their very short span of effectiveness which can be measured
in days.
The present invention suggests an absorbing sub-
stance ~or the removal Or the above-mentioned catalyst
poisoning gases, especially of antimony-hydride and arsenic-
hydride, from the oxyhydrogen gas mixtures ~hich are gen-
erated in electrical lead-acid storage batteries during
their operation as well as & method o~ producing such ;
~` absorbing substances. Furthermore the invention provides
for a device for the catalytic recombination o~ the oxy-
hydrogen gas produced by a lead-acid storage battery to
water and for returning the water to the battery electro-
lyte. The device comprises in combination: a generally
gastight housing arranged above the battery electrolyte
and connected with the space containing the latter for gas
~ flow communication and for liquid return ~low thereto; a `
-;1 20 catalyst body mounted in the cavity of the housing, the
catalyst body serving to recombine the oxygen and hydrogen
gases to water; a bed o~ an abosrbing substance surrounding -
the cataly~t body, the absorbing substance serving to
eliminate from the oxyhydrogen gas mixture the so-called
catalyst poisoning gases, e.g. antimony-hydride and arsenic-
hydride which are generated together with the oxyhydroge~ `~
gases during battery operation, and means ~or containing
the bed o~ absorbing substance around the catalyst body.
.:
The improved device substantially increases the duration of
` ~ 30 e~ectiveness of the catalyst.
The present invention suggests the use of heavy-
~ metal manganites of one or several metals as absorbing
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substances, preference bein6 given to copper manganite. In
place of this preferred group of compounds, it is also pos-
sible to use heavy-metal oxides for the removal of catalyst
poisoning gases from the oxyhydrogen gas mixture generated
by lead-&cid storage batteries~ For example, one may use
the oxides of the elements iron, cobalt, nickel, tin, gal-
lium, indium, and thallium, either separately or in com-
bination, for a reaction with the antimony-hydride and
arsenic-hydride to obtain hydrolysis-resistant arsenides
and antimonides in the form of intermetallic compounds.
These heavy-metal oxides may also be employed in combina-
tion with the aforementioned heavy-metal manganites to
obtain 8 suitable absorbing substance.
The present invention further proposes that the
absorbirg substance includes oxidic compounds of elements,
either of one or several types, or as an additive to the
heavy-metal oxides, these oxidic compounds being reduced in
the reaction with the antimony-hydride and arsenic-hydride,
under oxidation of the latter. Especially suitable for
this purpose are: molybedenum trioxide (MoO3), tungsten
trioxide (W03), and manganese dioxide (MnO2). Lastly,
the lnvention auggests that the ab~orbing substence include
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oxides which are catalytically active as oxygen transfer agents, the oxides
being used separately or in combination, or in addition to the heavy-metal
oxides. Suitable examples of such oxygen transfer oxides are, in particular,
ferric oxide (Fe203), vanadium pentoxide (V205), and chromium trioxide
(Cr203). These oxygen transfer agents cause an oxidation of the antimony-
hydride and arsenic-hydride, when they come in contact with these gases.
From the above, it can be seen that the various approaches to the
basic solution proposed by the invention relate to different reaction mech-
Qnisms which are operative in the reaction between the oxidic absorbing sub-
stances, and the antimony-hydride and arsenic-hydride. Thus, the first group
of oxidic compounds produces antimonides and arsenldes, while the two other
groups produce oxidic compounds of antimony and arsenic. In the first case,
the oxidation of the catalyst poisoning gases is obtained through the action
-~ of an oxidation agent, whereas the second case involves the catalytic trans-
fer of oxygen. However, it should be understood that the foregoing explana-
tion of the reaction mechanisms is based upon hypothetical assumptions which
were reached as a result of the research underlying the present invention.
The inventors, therefore, do not pretend that their hypotheses regarding the ~ --
aforementioned reaction mechanisms are necessarily complete and correct.
~owever, it has been found that each one of the substances listed herein
materially contributed to an improved de-poisoning of the oxyhydrogen gas
mixture which is given off in lead-acid storage batteries during operation.
Particularly good results have been obtained with heavy-metal manganites,
` especially with copper manganite.
The pre3ent invention also suggests ways of improving the effec-
tiveness of the aforementioned absorbing substances still further, by arrang-
ing the substance on a carrier material, preferably an alumina gel. The car-
rier itself is preferably in granular form, the grain size for use in con-
~unction with conventional automobile batteries ranging between 0.1 mm and
;30 1 mm, and preferably between 0.2 mm and 0.5 mm.
The present invention further suggests a method of producing the
absorbing substances mentioned earlier, the method being characterized in
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that a solution ~f a salt of the element, or elements, i8 producPd which, in
its oxidic form, reacts with antimony-hydride and arsenic-hydride to create
antimonide or arsenide, or their oxides, respectively, and that the carrier
material is introduced into this solution at an elevated temperaeure~that
following a period of interaction, the mixture is introduced into a sodium
carbonate solution or the like in order to precipitate the carbonate, and
that the substance is then washed, dried, and calcinated. Preferred operat-
ing conditions for the method of the invention are listed in the various
specific examples given further below.
Lastly, the invention suggests a novel device for the catalytic
recombination of the hydrogen and oxygen gases produced during the operation
a lead-acid storage battery, to obtain water and to return the latter to
; the electrolyte of the battery. This device is characterized by a generally
cylindrical housing which includes a stub connection on its outside and a
porous body mounted against one housing face, ad~acent to which is arranged
a catalyst body, the latter being surrounded by a uniform layer of a granular
. absorbing substance contained inside a sleeve surrounding the catalyst body.
~he catalyst body is preferably in the shape of a rod and retained by its
ends inside flanges in opposite end faces of the housing, whereby the flanges
also serve to position the gas-permeable sleeve concentrically in relation
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to the catalyst rod, the annular space between the sleeve and rod containing
the absorbing substance.
` The gas-permeable sleeve is preferably of a ceramic material. How-
,~ ever, it may also be in the form of a cylindrical screen, for example, a
; sleeve of wire mesh.
It was found to be advantageous to arrange one mounting flange in
s the hou8ing as out~ardly oriented extension, and to use a putty seal as a
closure for the flange opening, the putty seal also serving to position and
secure the catalyst rod, the absorbing substance, and the gas-permeable
slee~e.
Further special features and advantages of the invention will
,~ become apparent from the description following below, when taken together
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with the accompanying drawing which illu~trates, by way of example, a
preferred embodiment of the invention in the form of a catalytic recombina-
tion device, represented in the figure as follows:
The figure of the drswing illustrates in an elevational view,
partially shown in longitudinal cross-section, a device embodying the inven-
tion.
Commercially available lead-acid batteries of the type 12 volts -
45 amp hours with 5 positive and 6 negative plates in esch cell were used to
test the novel absorbing substance of the invention. The grid of each cell
plate was made of a lead alloy which contained approximately 5.5 percent
antimony and 0.15 percent arsenic. Each cell was closed hermetically by
mounting in its opening a recombination device of the type illustrated in the
drawing. The purpose of such a device is to recombine the hydrogen and
oxygen gases generated during the operation of the battery to water. The
recombination device includes a catalyst consisting of acatalyst carrier
i~ material, preferably palladium, the catalyst being provided in the form of a
rod 1, or in some other suitable geometric form. The length of the catalyst
rod 1 is several times larger than its diameter. This catalyst body is
accommodated inside a housing 4 of plastic material which has a substantially
~` 20 semi-cylindrical cross_section, the bottom 3 o~ housing 4 being inclined
~ toward a downwardly extending hollow stub connection 5 through which the gas
`` mixture enters into the housing and the recombined water returns to the
electrolyte of the battery. One end face of housing 4 has a laterQl opening
`` 6, a porous body 7 surrounded by a plastic plug 11 closing the opening 6
against the outside. The plastic plug 11 includes an inwardly oriented hol-
. . .
; low flange 8 extending into the housing 4 in the direction of an opposite end
face. This opposite end face of the housing includes an outwardly extending
flanKe 9 in alignment with flange extension 8 of the plastic plug 11. The
.~ :
catalyst rod 1 of the device extends between these two flanges 8 and 9, the
opening of n ange 9 being closed after assembly by a putty seal. -
The porous body 7 con~ists of a ceramlc mass which is made hydro-
phoblc by a known treatment. The inside of housing 4 thus forms a convenient
1066765
reaction space inside which the exothermic reaction of recombining the
hydrogen and oxygen gases to water under the influence of the earlier men-
tioned catalyst takes place.
In order to prevent the premature poisoning of the catalyst mate-
rial, a ceramic tube 10 is arranged between the flange extension ô and flange
9 of the housing in concentric arrangement with the catalyst rod 1 so as to
provide an annular space around the latter. Within this annular space be-
tween tube 10 and the catalyst rod 1 is contained a granular bed of sbsorbing
material 13, which thus surrounds the catalyst rod 1 in a uniform thickness.
~his bed of absorbing material 13 is preferably approximately 5 mm thick.
The aforementioned batteries were sub~ected to a test in which they were
overloaded with a current of 3 amps until the catalyst failed as a result
of poisoning. Whenever a battery was exhausted, the test devices would be
trans~erred to new batteries. The following absorbing substances have been
tested:
SubstanceEffectiveness
Silicagel 3 days
~, ~
Alumina gel 9 days
Various Nicrofilters max. 7 days
From the above listing, it can be seen that the effectiveness span of these
materials is extraordinarily short.
However, it was found that if a commercially available type of
alumina gel is used as a carrier material for a heavy-metal oxide, a con-
siderable improvement was achievable. The effectiveness in this case was
i~ extended to 483 days. This absorbing material was produced in the ~ollowing
~ manner:
,~t Example No. 1: A solution of 2.62 moles of CuS04 5 H20 per liter
was produced and into each liter of solution were introduced o.66 kg of dried
alumina gel, grain size 0.2 to 0.5 mm, at 80 C temperature. Following some
reaction time, the mixture was introduced into a 5-percent sodium carbonate
solution at 50 C temperature, whereupon the copper carbonate was precipitated.
Following washing, drying and calcination at 350C to 400 C, the substance
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1066765
was ready for use.
A markedly greater improvement of the effectiveness span was
achieved through the use of heavy-metal manganite~. Heavy-metal manganites
containing for example, between 50 and 95 percent MnO2 and, for example,
between 5 and 40 percent CuO, with a corresponding admixture of Co304,
Ni203, and Ag20, as well as mixtures of the aforementioned oxides, when
prepared on an alumina gel carrier or some other suitable carrying material,
are capable of increasing the longevity of the catalyst to in excess of 550
days. An absorbing substance of this type was produced as follows:
Example No. 2: A solution of 1 50 moles per liter of MnS04 -
4 H20, 1.10 moles per liter of CuS04 - 7 H20, and 0.15 moles per liter of
NiS04 - 7 H20 was prepared. Into one liter of this solution, heated at 80C
temperature, were introduced o.66 kg of dried alumina gel, grain size 0.2 to
0.5 mm. Following a reaction time of 90 minutes (under occasional stirring),
the mixture was introduced into 3 liters of a 5 to 10-percent solution of
Na2C03 at 50C temperature, so that the corresponding combination carbonates
were formed. Following a further reaction time of 30 minutes (under occa-
sional stirring), the product was washed, dried and calcinated for 30 to 60
minutes at a temperature between 350 and 400C, after which the substance
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~- 20 was ready for use.
During the aforementioned calcination treatment, under simultaneous ~-
exposure to air, the manganese and copper combination carbonates would create
copper manganites. The effectiveness span of this substance was found to be
578 days.
This remarkable improvement in the span of effectiveness has been
confirmed in connection with other substances which are available in oxidic
form, the primary characteristics developed through these research exper
iments and tests on absorbing substances capable of removing the hydrogen -~
compounds of arsenic and antimony, elements of Group V of the Periodic Table
of Elements, being the capability of forming arsenide and antimonide, re-
~pectively, with the component substances of the absorbing substance, and the
capability of oxidation or of oxygen transfer of the component substances in
~066765
the absorbing substance. As oxidation substances in this context shoula be
understood those compounds which are reduced ~n reaction with AsH3 and SbH3.
Oxygen transfer agents, on the other hand, are compounds whose catalytic
effect produces the reaction of AsH3 and SbH3 with 2
Consequently, a suitable absorbing substance may be composed Or
oxides of elements which create hydrolysis-resistant arsenides and anti-
monides, or respectively, oxidic compounds of arsenic and antimony. As
examples for such elements may be mentioned tin, nickel, cobalt, iron, copper,
silver, gallium, indium, Rnd thallium, but it should be noted that the
hydrolysis-resistant arsenides and antimonides of these elements no longer
possess the characteristics of a salt, but are presumably intermetallic com-
pounds.
; Apart from these oxides which are suitable for use as absorbing
substances, other elements in oxidic form may be used which qualify as oxida-
tion agents and oxygen transfer agents, such as for example: V205, Cr203,
Fe203, MoO3, and W03.
The aforementioned absorbing substances may be used separately or
as a combination of several arsenide and antimonide forming substances, pre-
`- pared either as a powder or in granular form, or as a preparation on a carrier
~` 20 material such as alumina gel, for example. Furthermore, these absorbing sub-
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stances, in addition to containing the aforementioned arsenide and antimonide
Porming compounds, may be admixed to one or several oxidation agents or
ox~gen transfer agents in powder form or granular form, or used as a prepara-
tion on a suitable carrier such as alumina gel, ~or example. Lastly, these
absorbing substances mR~ be composed of one or several oxidation agents or
oxidation transfer agents in powder form or granular form, or be in the form -~
of a preparation on a suitable carrier material, such as alumina gel, for
example.
It should be understood, of course, that the foregoing disclosure ~ -
describes only pre~erred embodiments of the invention and that it is intended
to cover all changes and modifications of these examples of the invention
which fall within the scope o~ the appended claims.
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