IMPROVEMENTS IN THE MANUFACTURE OF ALUMINIUM AND SODIUM
Year: 1858

page_text: .LETTERS PATENT to Frederick William Gerhard, of Tichborne Street,
Haymarket, in the County of Middlesex, Mineral Surveyer, for the
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF ALUMINIUM AND
SODIUM."
Sealed the 8th April 1859, and dated the 8th October 1858.
PROVISIONAL SPECIFICATION left by the said Frederick William
Gerhard at the Office of the Commissioners of Patents, with his
Petition, on the 8th October 1858.
I, FREDERICK WILLIAM GERHARD, of Tichborne Street, Haymarket, in the
County of Middlesex, Mineral Surveyor, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF ALUMINIUM AND
SODIUM," to be as follows:-
The object of this Invention is to manufacture aluminium in a
expeditious and economical way than heretofore, and to utilize a product
obtained during such manufacture. As the material from which to extract
the metal aluminium, I propose to use, as heretofore, the double chloride of
sodium and aluminium, or the double fluoride of sodium and aluminium
known as cryolite, or both of these substances combined. These substances,
when subjected to furnace heat in presence of the proper equivalent of sodium
for ensuring the separation or extraction of the aluminium in a metallic form,
I cover with a layer of fused chloride. of sodium, or of a mixture of this
Price 8d.]

page_text: substance and cryolite, or of the slag or scoria resulting from the process, and
thus prevent the destruction by ignition of the sodium.
In carrying out this part of my Invention, I prefer to employ a reverberatory
furnace having two hearths, one above the other; on the lower hearth I place
the mixed compound which is to be treated for the production of aluminium,
and on the upper hearth (which communicates with the lower one by a
discharging passage, while both communicate with the same fire-place and
flue), I place the chloride of sodium or other material which is to form the
covering for the mixed compound; I first direct the furnace heat over the
upper hearth, and when the material placed thereon is fused, I run it on to
the lower hearth in such quantity that it will completely cover the substance
placed thereon; I then direct the flame and heated gases over the lower
hearth and effect the rapid reduction of the aluminium. After the extraction
of aluminium from cryolite the residuum will be fluoride of sodium and
chloride of sodium (the latter having been added as a flux); I first remove the
chloride of sodium, and then pound the fluoride of sodium, and boil it with milk
of lime until it is decomposed, after which I separate the caustic soda from the
fluoride of calcium, and treat in the well-known way for recovering the sodium.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederick William Gerhard in the Great Seal Patent Office
on the 8th April 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
WILLIAM GERHARD, of Tichbourne Street, Haymarket, in the County of
Middlesex, Mineral Surveyor, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of October, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Frederick William Gerhard, Her special licence that I, the said
Frederick William Gerhard, my executors, administrators, and assigns, or such
others as I, the said Frederick William Gerhard, my executors, administrators,
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 "IMPROVEMENTS IN THE MANUFACTURE OF ALUMINIUM AND SODIUM,"

page_text: upon the condition (amongst others) that I, the said Frederick William
Gerhard, 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 Frederick William Gerhard, 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:-
more
The object of this Invention is to manufacture aluminium in a
expeditious and economical way than heretofore, and to utilize a product
obtained during such manufacture.
As to the material from which to extract the metal aluminium, I propose to
use, as heretofore, the double chloride of sodium and aluminium, or the double
fluoride of sodium and aluminium known as cryolite, or both of these substances
combined. These substances, when subjected to furnace heat in presence of
the proper equivalent of sodium for ensuring the separation or extraction
of the aluminium in a metallic form, I cover with a layer of fused chloride of
sodium, or of a mixture of this substance and cryolite, or of the slag or scoria
resulting after aluminium has been extracted, and thus prevent the destruction,
by ignition, of sodium, and consequently obtain a greater quantity of aluminium.
In carrying out this part of my Invention, I employ a reverberatory furnace
having two hearths, one above the other, or two reverberatory furnaces or
crucibles, one higher than the other, which communicate by means of an iron
pipe or discharging passage. In the lower furnace or crucible I place the
mixed compound which is to be treated for the production of aluminium, and
in the upper furnace I place the chloride of sodium or other material which is
to form the covering for the mixed compound in the lower furnace or crucible;
I then run it into the heated lower furnace or crucible in such quantity that it
will completely cover the substance placed therein; the furnace or crucible is
then kept at the proper heat until the contents are melted; it is then well
stirred and drawn off. After the extraction of aluminium from cryolite, the
residuum will be fluoride and chloride of sodium (the latter having been added
as a flux); I first remove the chloride of sodium, and then pound the fluoride
of sodium and boil it with milk of lime until it is decompozed, after which
I separate the caustic soda from the fluoride of calcium, and treat it in the
well-known way for recovering the sodium.

page_text: I desire it to be understood that I claim the process of pouring the melted
substance in the upper furnace or crucible over the contents in the heated
lower crucible or furnace, by which means a greater quantity of metal can be
obtained.
In witness whereof, I. the said Frederick William Gerhard, have
hereunto set my hand and seal, this Eighth day of April, in the
year of our Lord One thousand eight hundred and fifty-nine.
F. W. GERHARD. (L..S.)