IMPROVEMENTS IN THE MANUFACTURE OF ALUMINIUM, AND OF ALLOYS CONTAINING ALUMINIUM
Year: 1879

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF ALUMINIUM, AND OF ALLOYS CONTAINING ALUMINIUM.”
A communication from abroad by James Spooner Howard, Francis Gordon
Bates, and Frank Palmer Pendleton, all of Philadelphia, Pennsylvania, United
States of America.
Sealed the 19th August 1879, and dated the 17th April 1879.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 17th April 1879.
"
JOHN HENRY JOHNSON, of No. 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman. IMPROVEMENTS IN THE MANUFACTURE OF ALUMINIUM,
AND OF ALLOYS CONTAINING ALUMINIUM." A communication from abroad by
James Spooner Howard, Francis Gordon Bates, and Frank Palmer Pendleton, all of
Philadelphia, Pennsylvania, United States of America.
The first part of this Invention consists in economically manufacturing aluminium
by subjecting a mixture of oxide of aluminium, charcoal, or pulverized coal, and
common salt to heat in a closed crucible or furnace, as hereinafter described.
In carrying out this branch of the Invention oxide of aluminium is used, this
oxide being generally produced by dissolving alum in hot water, and adding to the
solution carbonate of soda to precipitate the oxide, which, after separation from the
solution, is washed and dried.
This oxide of aluminium is mixed with pulverized charcoal and common salt in
proportions which may be varied to some extent; it may be remarked however that
good results have been obtained by a mixture of three ounces of salt and one ounce
of charcoal to every pound of the oxide of aluminium. This mixture is placed in a
crucible, and the latter in a furnace, which should be maintained at a temperature
of, say, about 700° Fart. Care should be taken to close the crucible with an appro-
priate cover, to prevent as far as possible the escape of the vapors and gases.
In order to determine when the process has been completed the cover of the
crucible is slightly raised from time to time, and if it is found that the gases evolved
Price 31

page_text: have a bluish tint the crucible may be removed from the furnace and emptied, when
the aluminium will be found at the bottom.
Pulverized coal may be used in place of charcoal, but the best success has attended
the use of the latter.
The process may be conducted on a larger scale by subjecting the mixture to heat
in a closed furnace without a crucible.
The second part of the Invention consists of the economical mode hereinafter
described of making alloys, of which aluminium forms a part.
If an aluminium bronze, of which copper and zinc form parts, has to be made,
the copper is melted in an appropriate crucible, and while it is in a molten condition
oxide of aluminium and oxide of zinc are added and mixed thoroughly with the
molten copper, after which the crucible is closed and the application of heat con-
tinued. The mixing of the oxides with the molten copper should not be continued
for more than half a minute, after which a cover should be placed on the crucible,
or the contents of the crucible may be stirred through an opening in the cover, so
as to prevent, as far as possible, the escape of gases aud vapors.
In order to determine when the alloy is in a proper condition the cover of the
crucible is raised from time to time, and if it is found that the alloy is in a very
fluid state the crucible may be removed from the furnace; if it is found however
that the mass is in a thick semi fluid condition, it is an indication that it must be
subjected to heat for some time longer..
The proportion of the ingredients used will vary in accordance with the desired
character and color of the alloy. For an alloy of deep gold color, for example,
1 lb. of oxide of aluminium, 6 ounces of oxide of zinc, with 2 lbs. of copper, may
be used.
It is not necessary that the zinc which forms a part of this alloy should be
introduced in the condition of an oxide; metallic zinc in the desired proportion
may, for example, be introduced into the crucible containing the melted copper and
oxide of aluminium.
An alloy of copper and aluminium may be made by simply mixing the oxide of
aluminium with melted copper, and subjecting the mixture to heat, as above
described, but it has been found in practice that the addition of zinc, either in the
form of an oxide or metal, even if the proportion of zinc be very small, produces a
more perfect alloy than when the zinc is omitted.
An alloy of copper, tin, and aluminium may be made by first fusing the copper
and tin, and then adding the oxide of aluminium.
It will be understood that the proportions of metals alloyed with aluminium by
.the process may be varied as the desired product may suggest. Metals other than
those referred to may be added to the copper, or nickel may be added to white alloys
when a brilliant surface is desired.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the 6th
October 1879.
"
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. IMPROVEMENTS IN THE MANUFACTURE OF ALUMINIUM, AND OF
ALLOYS CONTAINING ALUMINIUM." A communication from abroad by James
Spooner Howard, Francis Gordon Bates, and Frank Palmer Pendleton, all of
Philadelphia, Pennsylvania, United States of America.
The said Invention consists, first, in economically manufacturing aluminium, by
subjecting a mixture of oxide of aluminium, charcoal, or pulverized coal, and common
salt to heat in a closed crucible or furnace, as hereinafter described.
In carrying out this branch of the Invention oxide of aluminium is used, this
oxide being generally produced by dissolving alum in hot water, and adding to the
solution carbonate of soda, to precipitate the oxide, which, after separation from the
solution, is washed and dried.
This oxide of aluminium is mixed with pulverized charcoal and common salt in
proportions which may be varied to some extent; it may be remarked however that
good results have been obtained by a mixture of three ounces of salt and one ounce
of charcoal to every pound of the oxide of aluminium. This mixture is placed in a
crucible, and the latter in a furnace, which should be maintained at a temperature
of, say, about 700 degrees Fahrenheit.
Care should be taken to close the crucible with an appropriate cover, in order to
prevent, as far as possible, the escape of the vapors and gases.
The time occupied in the production of the aluminium by this process varies
considerably. It has been produced after the crucible has been in the furnace for
fifteen minutes; at other times it has required twenty five minutes, and at other
times even a much longer time. This difference in the time during which the
crucible should remain in the furnace may be attributable to differences in the
character of the materials which have been used at different times, and to differences
in temperature.
In order to determine when the process has been completed the cover of the
crucible is slightly raised from time to time, and if it is found that the gases evolved
have a bluish tint, the crucible may be removed from the furnace and emptied, when
the aluminium will be found at the bottom.
Pulverized coal may be used in place of charcoal, but the best success has attended
to use of the latter.
The process may be conducted on a larger scale by subjecting the mixture to heat
in a closed furnace without a crucible.
The said Invention consists, secondly, of the economical mode hereinafter described
of making alloys of which aluminium forms a part.
If an aluminium bronze, of which copper and zinc form parts, has to be made,
the copper is melted in an appropriate crucible, and while it is in a molten condition
oxide of aluminium and oxide of zine are added and mixed thoroughly with the
molten copper, after which the crucible is closed, and the application of heat con-
tinued. The mixing of the oxides with the molten copper should not be continued
for more than half a minute, after which a cover should be placed on the crucible,
or the contents of the crucible may be stirred through an opening in the cover, so
as to prevent, as far as possible, the escape of gases and vapors.
The time taken to produce an alloy in a proper condition to be cast into ingots
will vary from about fifteen to about twenty five minutes, according to the propor-
tions and character of the ingredients, the degree of heat employed, and other
circumstances.
In order to determine when the alloy is in a proper condition the cover of the
crucible is raised from time to time, and if it is found that the alloy is in a very

page_text: fluid state the crucible may be removed from the furnace. If it is found however
that the mass is in a thick semi-fluid condition, it is an indication that it must be
subjected to heat for some time longer.
The proportion of the ingredients used will vary in accordance with the desired
character and color of the alloy. For an alloy of deep gold color, for example, one
pound of oxide of aluminium, six ounces of oxide of zinc, with two pounds of
copper may be used.
It is not necessary that the zinc which forms a part of this alloy should be intro-
duced in the condition of an oxide; metallic zinc in the desired proportion may,
for example, be introduced into the crucible containing the melted copper and oxide
of aluminium,
An alloy of copper and aluminium may be made by simply mixing the oxide of
aluminium with melted copper, and subjecting the mixture to heat, as above described,
but it has been found in practice that the addition of zinc, either in the form of an
oxide or metal, even if the proportion of zinc be very small, produces a more perfect
alloy than when the zinc is omitted.
An alloy of copper, tin, and alluminium may be made by first fusing the copper
and tin, and then adding the oxide of aluminium.
It will be understood that the proportions of metals alloyed with aluminium by
the process may be varied as the desired product may suggest. Metals other than
those referred to may be added to the copper, or nickel may be added to white alloys
when a brilliant surface is desired.
Having now described and particularly ascertained the nature of the said Inven-
tion, and the manner in which the same is or may be used or carried into effect, I
would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein before in part recited
Letters Patent is,―
First. The mode described of manufacturing aluminium, the said mode consisting
in subjecting a mixture of oxide of aluminium, carbon, and salt to heat in a closed
crucible or furnace, substantially as hereinbefore described.
Second. The mode described of producing aluminium alloys, the said mode con-
sisting in introducing oxide of aluminium into the molten metal or metals with
which the alluminium has to be alloyed, and subject the mixture to heat in a closed
crucible or furnace, all substantially as hereinbefore described.
In witness whereof, I, the said John Henry Johnson, have to this my Speci-
fication set my hand and seal, this Sixth day of October, One thousand
eight hundred and seventy nine.
J. HENRY JOHNSON. (L.S.)