THE MANUFACTURE OF ALUMINIUM AND OF CERTAIN RE-AGENTS TO BE USED THEREIN
Year: 1857

page_text: LETTERS PATENT to Sir Francis Charles Knowles, of Lovell Hill, in the
County of Berks, Baronet, for the Invention of "THE MANUFACTURE OF
ALUMINIUM AND OF CERTAIN RE-AGENTS TO BE USED THEREIN."
Knowles at the Office of the Commissioners of Patents, with his
Petition, on the 22nd June 1857.
I, Sir FRANCIS CHARLES KNOWLES, of Lovell Hill, in the County of Berks,
Baronet, do hereby declare the nature of the said Invention for the "MANU-
FACTURE OF ALUMINIUM AND OF CERTAIN RE-AGENTS TO BE USED THEREIN," to..
be as follows:-
My Invention consists of a method of preparing the cyanides of potassium
and of sodium, and in the use of those cyanides, in the making of the
metal aluminium.
To form the cyanides I combine carbonate of potash, or carbonate of soda,
as the case may be, with fine charcoal, in such a proportion as to convert the
carbonic acid into carbonic oxide by the action of heat, and to decompose the
alkali used. I place this mixture in a chamber, with lumps of charcoal, such.
chamber being of fire clay, fire brick, or iron, and then having heated the.
same sufficiently, I pass through it a current of the waste gases of blast
furnaces (or the same or similar gases obtained intentionally from a cupola
by a blast of air). The nitrogen contained in these gases combines with the
charcoal to form cyanogen, and this, uniting with the metallic base of the.
decomposed alkali, forms a vapour of the cyanide required, which can be
cooled and collected by sublimation in appropriate chambers. To make.
the metal aluminium, I take one or other of the above cyanides, and the.

page_text: chloride of aluminium, and by passing the vapour of the chloride of aluminium,
or otherwise combining the same with the melted cyanides, I obtain by double
decomposition chloride of sodium, or chloride of potassium, and the metal
aluminium, which can be readily collected and fused.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Sir Francis Charles Knowles in the Great Seal Patent
Office on the 22nd December 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Sir FRANCIS
CHARLES KNOWLES, of Lovell Hill, in the County of Berks, Baronet, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of June, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Sir Francis Charles Knowles, Her special licence that I, the said
Sir Francis Charles Knowles, my executors, administrators, and assigns, or
such others as I, the said Sir Francis Charles Knowles, my executors, admini-
strators, 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 Inven-
tion for "THE MANUFACTURE OF ALUMINIUM AND OF CERTAIN RE-AGENTS TO BE
USED THEREIN," upon the condition (amongst others) that I, the said Sir Francis
Charles Knowles, my executors or administrators, by an instrument in writing
under my or their, or one of their hands and seals, should particularly 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 I, the said Sir Francis Charles Knowles, 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 thereof, that is to say:-
My Invention consists of a method of preparing the cyanides of potassium
and of sodium, and in the use of those cyanides in the niaking of the metal
aluminium.

page_text: To form the cyanides I combine anhydrous carbonate of potash, or
anhydrous carbonate of soda, as the case may be, with fine charcoal in
such a proportion as to convert the carbonic acid into carbonic oxide by
the action of heat, and to decompose the alkali used. I place this mixture
in a chamber with lumps of charcoal, such chamber being of fire clay, fire
brick, or iron, and then having heated the same sufficiently, I pass through it
a current of the waste gases of blast furnaces used in smelting iron ores (or of
the same or similar gases obtained intentionally from a cupola by a blast of
air). The nitrogen contained in these gases combines with the charcoal to
form cyanogen, and this, uniting with the metallic base of the decomposed
alkali, forms a vapour of the cyanide required, which can be collected by
sublimation in appropriate chambers, and cooled.
To make the metal aluminium, I take one or other of the above cyanides,
and the chloride of aluminium, and by passing the vapour of the chloride of
aluminium through, or otherwise combining the same in the form of melted
chloride, or its vapour, with the melted cyanides, or their vapour, I obtain by
double decomposition chloride of sodium, or chloride of potassium, and the
metal aluminium, which can be readily collected and fused.
Pure alumina may be added to the materials to increase the yield of metal,
and to economise the cyanide; and this I recommend to be done in most
.
cases.
The proportions in which these elements decompose each other, and unite
in fresh combinations, may be taken as about the following (assuming chloride
of aluminium to consist of 2 equivalents of aluminium, and 3 equivalents of
chlorine, as at present received):
1 equivalent of chloride of aluminium, or 158 lbs.,
3 equivalents of cyanide of sodium = 148 lbs., or of potassium
196 lbs.
to which may be added, in order to increase the quantity of the metal
obtained, and to use up the cyanide completely and economically,
4 equivalents of alumina 206 lbs., or generally (to meet the doubt as
to the exact chemical composition of the chloride of aluminium),
3 equivalents of chloride of aluminium,
39 equivalents of cyanide of sodium or potassium, and
49 equivalents of alumina will be an equally convenient form, such
equivalents in numbers being taken from the best chemical tables
in use.
In forming the cyanides I do not limit myself to the use of any particular
form of vessel, or any particular mode of heating it, but I recommend the
combustion of a part of the furnace gases around the chamber containing the

page_text: mixture, or the retort, or other vessel, as a cheap mode of generating the heat
required, the adequacy of which can be ascertained at once by the evolution
of the vapour of the cyanide, through a trial tube of glass attached to the
apparatus. Neither do I limit myself to any special form of vessel for com-
bining the melted chloride of aluminium, or its vapour, with the cyanide
used, and the alumina, when that is added.
I also desire it to be understood that my process differs essentially from that
of putting either of the alkaline carbonates into a blast furnace (whether used
to smelt iron ores or not), and collecting the melted cyanides as they flow
down into the hearth of the furnace or elsewhere, the characteristic features of
my said process being the formation of the cyanides in vapour at a high
temperature, the leading away of this vapour by suitable pipes, and the
collection and cooling of it in separate vessels or chambers, distinct from
the generating furnace itself, whether the cyanides be formed by admixture
of the alkaline carbonates, as first above described, in an appropriate and
separate chamber, with charcoal, or in the body of the blast furnace itself
(such furnace not being an iron melting furnace, but one expressly employed
for the purpose), in contact with the fucl, coke, or charcoal, just above the
tuyere of the same, and by the heat generated by the blast.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I claim,-
First, the manufacture of the cyanides of potassium and sodium by the
formation, collection, and cooling, or sublimation of their vapour, by the means
and in the manner herein-before described.
Second, the manufacture of the metal aluminium by the double decomposi-
tion of the chloride of aluminium, or its vapour, and the cyanide of sodium, or
cyanide of potassium, or the vapour of either, in appropriate vessels, retorts, or
chambers, with or without the addition of pure alumina, in order to add to the
yield of metal, as herein-before described.
In witness whereof, I, the said Sir Francis Charles Knowles, have here-
unto set my hand and seal, this Nineteenth day of December, One
thousand eight hundred and fifty-seven..
FRANCIS CHARLES KNOWLES. (L.S.)