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Патент USA US2405580

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Aug. 13, 1946.
'Filed nec. 14, 1940
j.’ ¿if
Patented Aug. 13, 1946
Carey‘B.: Jackson,„Forest Hills, Pa., assigner to'.
Mine Safetyv Appliances Company; Pittsburgh',
Pa'. .
Application December 14, 1940", Serì'aLNo. 370,159'
10 Claims'.
This invention relates t'o- a methodl of? manu
facture of oxides-of metals, and-more particularly,
to a method and apparatus- which may be; used
to- produce> uniform-ly andf economically- oxides of
rn-et'al's;` such asßpotassium orv sodium ora mixture
thereof- and the pro'duct of which is especially
(Cl. 23-184J
amount oi'> time i's--stilly needed to complete the
reaction and it necessitates the use ci` consider
aktieI equipment if the product is to be manufac
tured" in- commercial quantities;
The physical characteristics of the resulting
productl of thisgeneral'methodiis dense and hard
adaptable as ' an air purifying' and oxygen'> evolv
and unsuitable for' use in respiratory apparatus
ing compound;
and no treatment hasbeen found which will make
_One of’ the methods heretofore available for
the-product ofr ay nat-ure that makes it suitable for
oxidizing these-alkali metals to- a high exi-destato- 10 this' purpose. In somel instances, the product
andv which method has had some> commercial
formed is so'lz‘ardv as to dissolve only slowly in
value- consists of vatw'o‘-step or two-stage methodv
Water, An air purifying composition,` in order't'o
of procedurea In this method, the pure metal i’s
be useful iny respiratory-»apparatus must _be-‘of a
oxidized iïrst-to a composition- approximatingxthe
porous-'nature or have such characteristics that it
metal monoxide and' this is accomplished bysub
is instantly'reactive with respiredY air by being
jecting the surface- of the-pure molten metalto
penetratie by 'carbon dioxide and Water to absorb
ani oxidizing atmosphere; The oxygen content
carbon dioxide and to»y evolve oxygenV to" replace
of the ñuid or atmosphere supplied- is limited to
to somev extent the; oxygen consumed.
less'than l0v per 'cent-because any-'greater amount
The-principal- object voi‘this inventionl is to pro
Yvoul'd produce an explosive> condition due tothe 20 vide a-'method--off forming' an oxide of a metal'
mass' involved
the vapori pressure of the
and'ì an apparatusA for performing the method
metall. The reaction itself> is sufficiently ex'
which is continuous, simple in operation, >inex
othermic to carry- the: reaction to'com-pletion- and
pensive and rapid in- performance and com
this provides a‘source of danger 'if too' much mass
mercially practicable and which»v is adaptable to
invoved at one time’. The high oxide orvper 2. produce potassium or'sodi-u-m- peroxide or a nii-x
oxide, which inV the- case of"potassi`um is potas
ture thereof of uniformj composition having defisium tetraoxide (K202i)- and in- the case ofl sodium
nite physical>> characteristics rendering the prod
if's- sodium- peroxide (Na202), is then` formed from
uct adaptable- ast an air purifying- composition,
the monoxide' by subjecting the surface of the
'lî'l'ie'f-methodî of' my' invention employs the treat-l
molten metal' monoxide to- ox-idizing- iiuid. This
ment- off' molten metal- W-_hich is-~ to; be reasonably
reaction- is not suñiciently exoth'ermic tor` carry
puI-‘e-y or at» leastI not' containing- any impurities
on the- reaction and heat must besuppliodvr conwhich would interfere with the process or prevent
tinuously. One of the principal di-ñîculties in- this
its being used for the purpose intended.- The
method is the fact that thereaction takes place
molten metal is made-to ñ'ow and in an atomized
slowly and it isj diiiicult- to produce a uniform» :‘ state to form- a stream of small or minute par--`
product. The motivating' force i'n thisI method
ticles and thisv stream is- then subjected to an
which would provide uniformity of composition
oxidizing atmosphere.. This atomization step
.in the-reactive mass is the- capillary movement of'
renders-the' me tal- i'ncreasingl‘y reactive and suiiî
the> materials and it is apparent that this is slow
cien-tly so that a substantially uniform oxidized
and'v very difficult tocontrol. Furthermore, this 40, product isy produced- in a rapid and inexpensive
method is‘ obviously very expensive to perform in
manner. In carrying out themethod for produc'
commercial quantities- due to the extensive equip
ing alkali peroxides, such as potassium peroxide,
ment required' in subjecting the surface-of the
a small` stream of' molten metal is directed into
materi'alè to Aan voxidizing atmosphereY in the two
a flow of iluid'` having an oxygen content of at
stages of- the method', and, also, in> performing ' least 1'3- per'cent by volume and preferably‘not
the second stage of- the process, a large amount
more than 35~ per» cent.' Within these limits of
of heat mustV be continuously added tothe massÍ
oxygen content, the- method can be carried on to
to oxidize' the metal> to the highestV availableV
the best advantage relative to _the rate of pro
-iuction, uniformityA and protection of apparatus;
In orderV tra-expedite this type -ofoxidi’zing pro» 50 Since the constituency of* ordinary- atmosphere
cedure, it has been suggested to supply the-molten`V
i's- Withinl the designate-d limits, it is suitable for
metal inv theform of'y thin layersI and then subject
the practice' of this method. By i-ntroducin'gja
these'- layers to the oxidizing atmosphere: Such
procedure would, no doubt, improve the uni
formity of the composition prepared‘,
a great
streaml of' themolten'metal into a- iioW of air, fine
sphericalï-like‘particles‘ or globules of material are
.fortified and suspended in the> flow, and an in
stantaneous or at least immediate oxidation oc
device in a thin or ñne stream of the molten
curs to the metal and this is carried directly and
quickly to the highest state of oxidation of the
metal. The oxygen content in air is ample to
oxidize the metal to the desired state for metals
like potassium provided sufñcient volume is sup
metal and which when being directed into the
will be hereinafter described as atomization. For
the purpose of collecting the o-xidized metal, a re
plied for mixingkwith the metal .in its atomized
ceiving chamber 8 is directly- connected to the
fluid ñoW is dispersed so as to form finely divided
particles of the molten metal, which operation
atomizing device and it has a vent ilu/connected
to the atmosphere so that an ordinary atmos
state. The fact that the overall reaction is
exothermic in these oxidation reactions and to a
.pheric condition exists within the chamber and
relatively large value, sufûcient heat is available
, Va discharge 8b is provided in its lower extremity.
to carry the reaction of all> the metal to com
pleticn by this continuous process.
,7, . .y i
“The op-eration of this device is not described in
'detail nor is the apparatus since it is a device
‘ wellv known inthe art and its principle of opera
the atomization of such reactive metal as potas
sium and sodium would be dangerous in that the l5 tion is likewise well' known.
In the use of such a device for the practice of
mixture of the metal with atmosphere would be
my method, the molten metal contained in the
dangerously explosive and thus> any such hazards
i ’ receptacle 5 is drawn into the passage 4 of the
would render the method impractical for com
housing proper by the flow of oxidizing fluid, in
mercial purposes. It has been found that by con
trolling the oxygen content Within the limits set 20 troduced into the passage 3, over the opening of
the passage 4 or in such relation that the molten
forth above, any such dangers are eliminated
_metal is discharged from the device in a small
sufliciently provided some care is taken in the
stream readily dispersable and into the stream
practice of the method and it can be and is being
of oxidizing iiuid producing the suction and car
performed on a commercial scale, with inexpen
sive apparatus and at a low cost of operation.
25 rying the formed metal particles or atomized
stream of metal into the »receiving chamber 8.
In order to prevent the oxide from becoming
The metalparticles are intimately mixed with
hard and of a high density, it is cooled quickly
the oxidizing fluid and because of this and the
by the flow of air and reduced below the fusion
molten state of the metal as well as the heat
temperature of the oxide. Ordinarily, atomlzed
molten metal when oxidized appears to burst 30 evolved, an instant reaction oi the metal and the
iiuid is caused to oxidize the metal completely
open or explode .the spherical shape or globule
to its highest state. No means or medium is re
type of particles, and when cooled it reassurnes
quired to initiate the reaction, since the molten
this globule shape due to the surface tension of
metal Vparticles in the oxidizing i‘luid flow are in
the material. This immediate cooling of the re
acted material appears to Vcause it to remain in 35 stantaneously reactive. The heat evolved also
accelerates the reaction and the excess of oxygen
the bursted condition,rit being what might be
present causes the oxidation to be rapidly carried
termed frozen in this condition, and this physi
to completion.
cal condition is of an aborescent, or fluffy, nature
In employing this process in a commercial
in structure and because of this property is espe
It was thought that any method based upo `
For the purpose of aiding in giving a full and
complete description of the method, an appara
mannerto produce potassium tetra-oxide, it be
ing understood that any reference to peroxide is
to be-construed to mean the highest state of ox
tus is illustrated anddescribed which has been
used for producing potassium tetra-oxide in com
mercial quantities. Referring to the drawing, the
use, the oxidizing ñuid flow is produced by con
necting thepassage 3 o-f the housing to a source
cially adaptable for respiration apparatus.
apparatus is simply a iluid spray device such as
is used to apply paints or other coating on to
surfaces and which has been found to be adapt
able to discharge a thin or ñne stream o_f metal,
idation attainable and suitable» for commercial
` ot ordinaryv atmosphere or airat a'suiiiciently
high pressure. In one instance, which has proven
to be a commercial application, the air is at about
20 pounds pressure and at a temperature of about
this being controlled by an adiustment which 50 75° C. YThe potassium metal is heated to a molten
state and maintained in this state during the
forms a part of the device. The stream is diverted
performance of the method and is preferably at
into an air flow which effects an atomization
of the metal,
The device is made of a metal material which
is not affected by the temperatures involved in >
this method and comprises a housing I having
a passage 3 and a passage 4.
These passages
are connected to suitable tubes, which in turn
are connected to a source of oxidizing iluid and
to the molten metal, respectively. A vented re
ceptacle 5 contains the molten metal and a tube
4a connected to the passage 4 is inserted there
in. An opening ‘I is provided in the housing for
a temperature several degrees aboveits melting
point. In> any event, the temperature should be
such that a slight reduction would not cause a
solidiñcation or Aany thickening of the molten
metal and prevent its being readily and efficiently
atomized or discharged in a stream atomized by
impingement against a stream of air. For some
purposes, it maybe advisable to provide some
form of an'inert atmosphere over the surface
ofthe metal contained in the receptacle 5 in
order to prevent any contamination of the metal
before it is introduced into the atomizing device.
the passage 4, while Van opening E Which is aligned
By heating the compressed air to a tempera
With the opening 1 isprovided for the passage 3.
ture of >about 75°C., the metal within the hous
The oxidizing :duid under pressure is intro
ing I, or specifically within the passage 4, is main»
duced into the housing through the passage and
tained in a molten state while passing through
completely encircles the passage 4 containing the.
the device. However, this function of the air
molten metal and by being discharged at a rela-Y
tively high velocity at the opening-5 and over. 70 more or less ancillary because in using air for the
practice of my method the oxygen of the airis
the opening 1 is effective tol draw the molten
the source supplied for oxidizing lthe potassium.
metal up into the passage and against a needle
While the nitrogen of the air, inert to potassiumV
adjustment 9. This adjustment controls the dis
or the formed oxide, cools the peroxide in a pref
charge of the metal particles from the device
and by such the metal is discharged from the
scribedmanner. `
supplied is for the purpose of keeping the metal
an amount such as to' provide an excess of OXY
gen `over that theoretically necessary forA >said
oxidation and such, relative to its temperature,
in a molten state at the time of discharge into the
stream of oxidlizing iiuid. The heat in the molten
as to quench the oxideV below its melting point
the Vheat evolved bythe reaction accelerates the Ul substantially as rapidly as it is formed, and
thereby-producing the peroxide in a iiuiiy and
metal is adequate to initiate the-oxidation and
- In> all cases of application of my method, the
uniformly oxidized form of low apparent density
chemical properties of the selected metal‘must be
considered in adapting my ìnventionto the metal.
The properties of the metal upon' which> the
method depends are'known and the adaptation of
and of high reactivity with exhaled air.
4. A method according to claim 3, said atmos->-phere being air.
V '
» 5. That method of making alkali' metal per'
oxide which comprises atomizing molten alkali
those skilled in the art. By proper control of the
metal at a temperature above but close to its
dow of the molten metal and the oxidizing fluid,
melting point into a current of air heated to a
the`desir'ed oxidation product can be produced; 15 temperature -to maintain the metal particles
molten and'thereby rapidlyv oxidizing the metal
However, the metal to be oxidized must be such
my method to the selected metal can be made by
that it can be atomized in a molten state and in-V
particles to peroxide, and supplying said current
termixed in 'an oxidizing iiowand which by atom
of air in an amount such as to provide an excess
ization' becomes suiliciently reactive within the
apparent limits of the invention to form the de
sired oxidation product. '
of oxygen over that-theoretically necessary for
said oxidation and such, relative to its tempera
ture, as to quench the oxide below- its melting
One of the conditions that appears to lessen
point substantially as rapidly as it is formed, and
the hazards that exist in treating the highly re
therebyproducing the peroxide in a iluiïy and
active alkali metals is the vacuum that is utilized
uniformly oxidized form of low apparent density
in atomizing the molten metal. It is apparent 25 and of high reactivity with exhaled air.
that if a positive pressure sufficient to move the
6. 'A method of making potassium tetroxide
metal to the point of discharge and then dis
according to claim 5, said metal being potassium,
charge it at a sufliciently high velocity is applied
and the potassium and air being heated to about
tothe >metal and the metal under pressure in
’75° C.
troduced into a iiow of oxidizing ñuid that'some
7. That method ofv making alkali metal per
conditions might be created for certain metals
oxide- which comprises providing a body of at
which would result in avery hazardous condition'
least one metal of the group consisting of sodium
of operation. Consequently, this method of dis
and potassium in the molten state, continuously
charge of the metal is preferred although it is
atomizing the molten metal with a stream of gas'
apparent that it is not indispensable in the prac 35 under pressure and containing from about 13 to
tice of the method. This vacuum also eliminates
about 35 per cent of oxygen and substantially
all of the remainder inert to said metal, said gas
being heated to a temperature to maintain said
any premature firing or ignition of _the metal.
.~'It'is `intended that this detailed ‘description
of my method vas speciñcally‘applied to the oxi
metal molten, and regulating said stream to pro
dation of alkali metals, and particularly of po 40 vide an excess of oxygen over that theoretically
tassium metal, discloses the principle involved
necessary to convert said metal to the~ peroxide
and the exemplary ' vapparatus by which- the
methody can be carried on satisfactorily are what
state and such, relative to its temperature, as to
I now consider to be the best application lof 'my
invention, but it is intended that the invention beV .
stantially as rapidly as it is formed, and there
by producing the peroxide in a fluffy and uni
limited only by the scope of the appended ~claims._
formly oxidized form of low apparent density
and ofhigh reactivity with exhaled air.
quench the peroxide-below its melting point sub
' I claim:
'1. That method of :making alkali metal ox-l
8. A method according'to claim 7, said metal
being postassium and said peroxide being po
. .ide which comprises spraying'molten alkali metal
into a current of an "atmosphere containing oxy- i
gen and a gas inert to’said metal and thereby
9. A method according to claim 7, said metal
oxidizing the metal rapidly, and supplying said
atmosphere in an amount such as' to'provide an
excess of oxygen over that theoretically neces
sary -for 'said oxidation and such, relative to its"
being potassium, said peroxide Vbeing potassium
tetroxide, and said current of air being supplied
in an amount such as to provide from about `5
„ to about l5 times the amount of oxygen theo
retically necessary for oxidizing the metal.
temperature, as to quench the' oxide below its
melting point substantially as rapidly as it is
formed, and thereby producing the oxide in a
iiuiîy and uniformly oxidized form of low appar
ent density.
. 10. That method of making peroxide of metal
of the group consisting oi sodium and potassium
which comprises spraying the molten metal in
> 2. A method according to claim l, said atmos
a current of an atmosphere of gas inert to the
metal and containing oxygen into a chamber
phere being heated prior to contact with said
heated only by the heat liberated therefrom,
sprayed metal to a temperature to maintain said
alkali metal molten during oxidation.
3. That method- of making alkali metal perox-~'
ide which comprises atomizing molten alkali
metal into a current of an 4atmosphere contain
ing about 13 to about 35 per >cent of oxygen and
a gas inert to said metal and heated tov a tem-
perature to maintain said metal molten and
thereby oxidizingthe particlesof'metal rapidly
to peroxide, and supplying said atmosphere in
supplying said atmosphere in an amount such as
to provide oxygen in excess of that necessary for
- said oxidation and such, relative to its temper
ature, as to quenchv the peroxide formed below
its melting point substantially as rapidly as it is
formed, and thereby producing said oxide in a
highly porous andA reactive form of low appar
ent density.
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