A NEW OR IMPROVED PROCESS FOR THE MANUFACTURE OF OXYGEN
Year: 1865

page_text: LETTERS PATENT to Jules Théodore Anatole Mallet, Engineer, of 29,
Boulevart St. Martin, Paris, for the Invention of "A NEW OR IMPROVED
PROCESS FOR THE MANUFACTURE OF OXYGEN."
Sealed the 8th May 1866, and dated the 14th November 1865.
PROVISIONAL SPECIFICATION left by the said Jules Théodore Anatole
Mallet, at the Office of the Commissioners of Patents, with his Petition,
on the 14th November 1865.
I, JULES THEODORE ANATOLE MALLET, Engineer, of 29, Boulevart St.
Martin, Paris, do hereby declare the nature of the said Invention for " A NEW
OR IMPROVED PROCESS FOR THE MANUFACTURE OF OXYGEN," to be as follows:-
My Invention consists in extracting oxygen from air through the medium
of certain metallic chlorides, such as the chloride of copper, which in my
Specification I will take as a specimen, without limiting myself, however, to
such chloride, but still reserving the use of all the like chlorides, giving the
same reactions and which are capable of yielding the same results. I operate
by means of oxychloride of copper Cu Cl CuO, obtained by the various
chemical means. The oxychloride Cu Cl CuO may be obtained in various
ways either by simply effecting a mixture in equivalent proportions of chloride
Cu Cl and protoxyd of copper, or in treating the oxychloride known by the
name of Brunswick green with a sufficient proportion of hydrochloric acid to
bring it back to the composition Cu Cl CuO. The starting point may also be
the protochloride Cu² Cl, obtained by known chemical processes. This oxy-
chloride heated in closed vessels at a temperature of three hundred to four
hundred degrees evolves oxygen, leaving for residue protochloride of copper

page_text: Cu Cl, which being exposed to the action of air will absorb some oxygen,
and again become oxychloride Cu³ ClO, or Cu Cl CuO, which is one and
the same thing. This material being heated will again yield oxygen and
so on, the chloride of copper is therefore but an agent for fixing the oxygen
of the air and giving it off in presence of a suitable temperature. Practically
I operate in the following manner:-The oxychloride is mixed with twenty-.
five to thirty per cent. of its weight in an inert material, such as sand,
pulverized fire-brick, calcined sulphate of lime or kaolin, to prevent the
said material from undergoing an igneous fusion, and giving a hard compact
residue which would adhere to the sides of the vessels, and would not be
easily revivified. The mixture once made is heated to a dark red in
vessels of any form, preferably of fire-clay, and resembling more or less
gas crucibles. The oxygen evolving therefrom passes through a washing
vessel, which detains the steam and any chloride of copper which may have
passed out. When the evolving action is over the material is removed, being
immediately sheltered against the atmospheric air until it is cooled; it is
then crushed roughly and submitted to the action of atmospheric oxygen
either in the open air or upon boards in closed chambers, subject to the action
of a current of air incessantly renewed. The transformation into oxychloride
is ascertained by the green color assumed by the material; twelve hours will
generally suffice for the revivification, though more time is required in very
dry weather, in which case it may be proper to render the air damp by any
artificial means, as the steam performs a part in the revivification, the
oxychloride of copper being a mixture or a combination of chloride of copper
Cu Cl, and hydrated protoxyd of copper. The material being still capable of
yielding oxygen it may be dried or desiccated before being decomposed,
but in most cases this is quite unnecessary, the presence of steam not being
objectionable. The oxychloride will yield theoretically seven per cent. of its
weight in oxygen, experience having proved that ninety per cent. of the
said amount may be obtained. If twenty-five per cent. of inert material
are added two hundred pounds of the mixture will in practice yield ten
pounds of oxygen, say three and a half cubic yards, or about one hundred
and twenty-five cubic feet. The gas thus obtained is very pure and can
be produced at a very low price, the only cost in materials being the fuel
and the chloride of copper lost or wasted in manipulations, a loss which
may be rendered very trifling by taking proper precautions. I wish it
to be distinctly understood that I do not limit myself to the use of the par-
ticular chloride alluded to in the commencement of this Specification, but that
my Invention consists in preparing oxygen by means of the decomposition by

page_text: heat of the oxychloride of copper and other like chlorides, the solid residue
of the operation being transformed anew into oxychloride by the action of
atmospheric air.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Jules Théodore Anatole Mallet in the Great Seal Patent
Office on the 12th May 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JULES
THEODORE ANATOLE MALLETT, Engineer, of 29, Boulevart St. Martin, Paris,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of November, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Jules Théodore Anatole Mallet, Her special licence that I, the said
Jules Théodore Anatole Mallet, my executors, administrators, and assigns,
or such others as I, the said Jules Théodore Anatole Mallet, my executors,
adininistrators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend, within
the United Kingdom of Great Britain and Ireland, the Channel Islands, and
Isle of Man, an Invention for "A NEW OR IMPROVED PROCESS FOR THE MANU-
FACTURE OF OXYGEN," upon the condition (amongst others) that I, the said Jules
Théodore Anatole Mallet, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should particu-
larly describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that 1, the said Jules Théodore Anatole Mallett, do
hereby declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and
by the following statement (that is to say):-
My Invention consists in extracting oxygen from air through the medium
of certain metallic chlorides, such as the chloride of copper, which in my
Specification I will take as an example, without limiting myself, however, to
such a chloride, therefore reserving the use of all like chlorides, giving

page_text: the same reactions, and which are capable of yielding the same results.
operate by means of oxychloride of copper Cu Cl CuO, obtained by the various
chemical means. This oxychloride heated in a closed vessel at a temperature
of from three hundred to four hundred degrees (about a dark red heat),
evolves oxygen, leaving for residue protochloride of copper Cu³ Cl, which ou
being exposed to the action of air will absorb some oxygen and again become
oxychloride Cu² CIO, or Cu Cl CuO, which is one and the same thing as the
inaterial first employed. This material being heated will again yield oxygen
and so on. The chloride of copper is therefore but an agent for fixing the
oxygen of the air and giving it off in presence of a suitable temperature.
Practically I operate in the following manner :-The oxychloride Cu Cl CuO
may be obtained in various ways either by simply effecting a mixture in equi-
valent proportions of chloride Cu Cl and protoxide of copper CuO, or in
treating the oxychloride known by the name of Brunswick green Cu Cl³ CuO,
with a sufficient proportion of hydrochloric acid to bring it back to the com-
position Cu Cl CuO, or lastly by adding to the Brunswick green two equiva-
lents of chloride Cu Cl. I may also take protochloride Cu² Cl, obtained by
known chemical processes, and by exposing it to the oxygen of the air obtain
the oxychloride required. This latter method constitutes the revivification of
the oxychloride, as will be herein-after described. The primary material
obtained is mixed with from twenty-five to thirty per cent. of its weight of
an inert material, such as sand, pulverized fire-brick, calcined sulphate of lime
or kaolin, to prevent the said material from undergoing an igneous fusion,
and producing a hard compact residue which would adhere to the sides of the
vessel, and would not be easily revivified. The mixture once made is heated
to a dark red in vessels of any form, preferably of fire-clay, and more or less
resembling gas retorts. The addition of the inert substance to the oxy-
chloride is for the purpose of preventing the material from melting, and of
forming a very hard and compact mass when cooled, but this addition is also
necessary to prevent its becoming sufficiently liquid to be absorbed by the
earthen vessels. I may also diminish the proportion of inert material or operate
at a higher temperature which will render the decomposition more rapid; for
this purpose the retorts should be lined with a material proof against the
action of the material under treatment. I would especially mention compo-
sitions with a base of borate, silicate, or phosphate of copper, on which the
chloride of copper exerts no action, without however limiting myself to their
exclusive use. The oxygen evolving therefrom is passed through a washing
vessel which detains the steam and any chloride of copper which may have
passed out. When the evolving action is over the material is removed,

page_text: being immediately protected from the action of atmospheric air until it is
cooled, it is then roughly crushed and submitted to the action of atmospheric
oxygen, either in the open air or upon boards in closed chambers, in which
currents of air are introduced. The greyish brown color of the material is
now changed to a green shade; twelve hours will generally suffice for the
revivification, though more time is required in very dry weather, in which
case it may be proper to render the air damp by any artificial means, or to
slightly damp the material as the steam performs a part in the revivification,
the oxychloride of copper being a mixture or a combination of copper
Cu Cl, and hydrated oxide of copper. The material being still capable of
yielding oxygen it may be dried or desiccated before being decomposed, but
in most cases this is quite unnecessary, the presence of steam not being objec-
tionable. I would simply observe that a small amount of hydrochloric acid
will be produced in the presence of steam, which acid being retained in the
washing vessel serves for acidulating the water used to sprinkle the material
to be revivified. If it is desired to operate in an intermittent manner for pro-
ducing but a small amounts of oxygen the material may be left in the retorts
which have served for the decomposition, and when cooled or nearly so I
operate the revivification in the same vessels by causing a current of air to
circulate therein. When the revivification is terminated, or when it is desired
to obtain oxygen, the material is again heated; this method is of advantagefor
operating on a small scale, as it saves the transport and manipulation of the
material. It is necessary, whatever the method of operation, to protect the
material from the action of the air until it is cooled, otherwise chloride of
copper would give out noxious vapours produced by the contact of air. I
should, however, here remark that the revivification is facilitated by operating
slightly above the ordinary temperature either by passing currents of air at
trom 120 to 140 degrees Fahrenheit, the air containing steam, which as I have
beforementioned favours its action, orin the second method of operation before
described by the introduction of air, while the retorts are still slightly heated.
The oxychloride will yield theoretically seven percent.of itsweight in oxygen,
experiencehaving proved that ninety percent.of said amount maybe obtained.
If twenty-five per cent. of inert material be added two hundred pounds of the
mixture will in practice yield ten pounds of oxygen, say three anda half cubic
yards, or about one hundred and twenty-five cubic feet. The gas thus obtained
is very pure, and can be produced at a very low price, the only cost in materials
being the fuel and the chloride of copper lost or washed in manipulations, a
loss which may be rendered very trifling by taking proper precautions. It may
happen that the proportion of chlorine will at length become reduced in the

page_text: material by the volatilization of a small amount of chloride or from other
cause, and if it is found that the production of oxygen is diminished from
these causes it is only necessary to add a small quantity of hydrochloric acid
to the material to return it to its original condition or to make use of the
washing water also containing such acid as before-mentioned.
Having described the nature of my Invention and the mannerof performing
the same, I declare that what I claim as my Invention to be protected by the
herein-before in part recited Letters Patent is, preparing oxygen by means of
the decomposition by heat of the oxychloride of copper and other like oxy-
chlorides, the solid residue of the operation being transformed anew into
oxychloride by the action of atmospheric air.
In witness whereof, I, the said Jules Théodore Anatole Mallet, have
hereunto set my hand and seal, this Eleventh day of May, in the year
of our Lord One thousand eight hundred and sixty-six.
A. MALLET. (L S.)