IMPROVEMENTS IN OBTAINING ALUMINIUM FROM ITS ORE AND FROM OTHER SUBSTANCES
Year: 1883

page_text: LETTERS PATENT to Henry Arthur Gadsden of Australian Avenue in the City
of London for an Invention of IMPROVEMENTS IN OBTAINING ALUMINIUM
FROM ITS ORE AND FROM OTHER SUBSTANCES a communication from Emerson
Foote, a person resident at New York, in the State of New York, United
States of America
PROVISIONAL SPECIFICATION left by the said Henry Arthur Gadsden at
the Office of the Commissioners of Patents on the 16th October 1883.
HENRY ARTHUR GADSDEN of Australian Avenue in the City of London
"IMPROVEMENTS IN OBTAINING ALUMINIUM FROM ITS ORE AND FROM OTHER
SUBSTANCES (a communication from Emerson Foote a person resident at New
York in the State of New York, United States of America)
"
Heretofore the practised method of obtaining metallic aluminium as described
for instance in Watt's Dictionary of Chemistry Vol I, page 150, has been to treat
the chloride of the metal with metallic sodium as a reducing agent. But the great
trouble in handling metallic sodium, and the high cost of that metal have made this
process for producing aluminium very difficult and expensive
The present invention differs materially from the process heretofore generally
employed for obtaining aluminium (as given in Watt's Dictionary) It also differs
from other processes practised or described, so far as I know up to the present time,
and is an improvement upon the invention described in the specification of my
application for Letters Patent N° 1995 dated April 19, 1883.
According to the present invention I simultaneously generate sodium vapour and
a volatile compound of aluminium in two separate vessels or retorts and 'minglé
the vapours thus obtained in a third vessel wherein they re-act upon each other,
producing metallic aluminium which is precipitated upon the bottom of the vessel.
In carrying out this invention the aluminous materials may be converted into
any of the volatile compounds of aluminium, either by the ordinary processes, or
by those described in my above named specification N° 1995 of 1883, but it is.
preferred to convert it into the form of double chloride of aluminium and sodium,*
and in describing in detail how this invention is carried out I shall describe the
process in which this double chloride is used.
To this end I take the aluminous material, which may be alumina, corundum,
bauxite, or other suitable aluminous substance, and calcine it. Of this calcined
mass I take say 100 pounds and grind it to a fine powder and mix it with

page_text: about 50 pounds of chloride of sodium, and about the same amount of carbonaceous
material. For this last purpose equal parts of starch and powdered charcoal, or oil
and powdered charcoal, give good results. To the mixture of aluminous and
carbonaceous materials with chloride of sodium, is added sufficient water to bring
the same to a pasty condition. It is then made into cakes or balls and dried.
The dried cakes, or balls are then put into a suitable retort wherein they are heated
to redness, and at the same time a stream of chlorine gas is passed through the
retort so as to penetrate all through the material contained in it. The action of
chlorine upon the aluminous material in the presence of chloride of sodium, results
in the formation of the double chloride of aluminium and sodium.
The simple
chloride of aluminium might be made and used instead of the double chloride by
not mixing the chloride of sodium with the aluminous material, but it is preferred
to use the double chloride. This double chloride vapourizes as fast as produced
and passes over through a tube into a properly constructed vessel, chamber or
receiver. Sodium vapour also enters this same chamber through a second tube,
such sodium vapour being generated by heating a mixture of carbonate of soda or
other suitable compound of sodium, with charcoal or other reducing agent in
another retort similar to that in which the double chloride is produced-the
proportion of carbonate of soda or its equivalent to charcoal or its equivalent, being
two of the former to one of the latter, by weight.
The two vapours-the sodium vapour and the double chloride of aluminium and
sodium vapour-meeting in the chamber re-act upon one another forming metallic
aluminium and chloride of sodium-the metal falls to the bottom of the chamber
and collects there in the form of globules. The chloride of sodium condenses and
also collects upon the bottom, and it serves as a slag to protect the globules, and as
a flux to unite them. If desired, additional flux such as chloride of potassium
cryolite, et cetera, may be put into the chamber.
The globules of metals may be removed from the bottom of the chamber from
time to time and melted together in large crucibles and cast into ingots. It is well
to have more than one retort for generating the double chloride vapour, for in this
way the flow of the two vapours may be made continuous, one or more retorts
being always kept working while the others are being charged. These retorts as
well as the chamber in which the vapours are brought together may all be placed
in one furnace and heated by the same fire. In that case the retorts would receive
the first heat of the fire and the chamber would be heated by the products of
combustion after leaving the retorts.
I have described what has been found by experiment to be the best way of
carrying out this invention. But I desire it to be understood that I do not confine
myself to the use of the double chloride of aluminium and sodium; the given
aluminous material,-alumina, bauxite, et cetera, might be converted into any other
compound of aluminium capable of being vaporized, as, for example, the double
chloride of aluminium and potassium, the simple chloride of aluminium, the fluoride
of aluminium, or the double fluoride of aluminium and sodium or potassium,
et cetera, et cetera.
It is also evident that potassium vapour could be employed in place of sodium
vapour.
As above described, the vapour of the double chloride of aluminium and sodium
passes directly from the retort in which it is generated into the vessel wherein the
reaction takes place; but, if desired, this vapour may be condensed in a proper
vessel and re-volatilized.
This invention broadly stated consists in combining aluminous material to be
reduced and a reducing agent, both in vapour form, in a proper chamber, the said
vapors being generated in two separate retorts or in two separate sets of retorts.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Arthur Gadsden in the Patent Office on the 16th April
1884,
HENRY ARTHUR GADSDEN of Australian Avenue, in the City of London,
IMPROVEMENTS IN OBTAINING ALUMINIUM FROM ITS ORE AND FROM OTHER
SUBSTANCES (a communication from Emerson Foote, a person resident at New
York, in the State of New York, United States of America).
Heretofore the practised method of obtaining metallic aluminium as described
for instance in Watt's Dictionary of Chemistry Vol I, page 150, has been to treat
the chloride of the metal with metallic sodium as a reducing agent. But the great
trouble in handling metallic sodium and the high cost of that metal have made
this process for producing aluminium very difficult and expensive.
The present invention differs materially from the process heretofore generally
employed for obtaining aluminium (as given in Watt's Dictionary). It also differs
from other processes practised or described so far as I know up to the present time
and is an improvement upon the invention described in the specification of my
application for Letters Patent No 1995 dated April 19, 1883.
According to the present invention I simultaneously generate sodium vapour
and a volatile compound of aluminium in two separate vessels or retorts and
mingle the vapours thus obtained in a third vessel wherein they re-act upon each
other, producing metallic aluminium which is precipitated upon the bottom of the
vessel.
In carrying out this invention the aluminous materials may be converted into
any of the volatile compounds of aluminium either by the ordinary process, or by
those described in my above named specification N° 1995 of 1883, but it is
preferred to convert it into the form of double chloride of aluminium and sodium,
and in describing in detail how this invention is carried out I shall describe the
process in which this double chloride is used.
To this end I take the aluminous material, which may be alumina, corundum,
bauxite or other suitable aluminous substance and calcine it.
Of this calcined mass I take say 100 pounds and grind it to a fine powder and
mix it with about 50 pounds of chloride of sodium and about the same amount of
carbonaceous material. For this last purpose equal parts of starch and powdered
charcoal, or oil and powdered charcoal, give good results. To the mixture of
aluminous and carbonaceous materials with chloride of sodium, is added sufficient
water to bring the same to a pasty condition. It is then made into cakes or balls
and dried.
The dried cakes or balls are then put into a suitable retort wherein they are
heated to redness and at the same time a stream of chlorine gas is passed through
the retort so as to penetrate all through the material contained in it. The action
of chlorine upon the aluminous material in the presence of chloride of sodium,
results in the formation of the double chloride of aluminium and sodium. The
simple chloride of aluminium might be made and used instead of the double
chloride by not mixing the chloride of sodium with the aluminous material but it
is preferred to use the double chloride.
This double chloride vapourizes as fast as produced and passes over through a
tube into a properly constructed vessel, chamber or receiver. Sodium vapour also
enters this same chamber through a second tube, sach sodium vapour being
generated by heating a mixture of carbonate of soda or other suitable compound
of sodium, with charcoal or other reducing agent in another retort similar to that

page_text: in which the double chloride is produced-the proportion of carbonate of soda or
its equivalent to charcoal or its equivalent, being two of the former to one of the
latter, by weight. The two vapours-the sodium vapour and the double chloride
of aluminium and sodium vapour-meeting in the chamber re-act upon one
another forming metallic aluminium and chloride of sodium-the metal falls to
the bottom of the chamber and collects there in the form of globules. The chloride
of sodium condenses and also collects upon the bottom, and it serves as a slag to
protect the globules, and as a flux to unite them. If desired additional flux such
as chloride of potassium, cryolite, et cetera, may be put into the chamber.
The globules of metals may be removed from the bottom of the chamber from
time to time and melted together in large crucibles and cast into ingots.
It is well to have more than one retort for generating the double chloride vapour,
for in this way the flow of the two vapours may be made continuous, one or more
retorts being always kept working while the others are being charged. These
retorts, as well as the chamber in which the vapours are brought together, may all
be placed in one furnace and heated by the same fire. In that case the retorts
would receive the first heat of the fire and the chamber would be heated by the
products of combustion after leaving the retorts.
I have described what has been found by experiment to be the best way of
carrying out this invention. But I desire it to be understood that I do not confine
myself to the use of the double chloride of aluminium and sodium; the given
aluminous material,-alumina, bauxite et cetera might be converted into any other
compound of aluminium capable of being vapourized, as for example, the double
chloride of aluminium and potassium, the simple chloride of aluminium, the fluoride
of aluminium, or the double fluoride of aluminium and sodium or potassium,
et cetera, et cetera, It is also evident that potassium vapour could be employed in
place of sodium vapour.
As above described, the vapour of the double chloride of aluminium and sodium
passes directly from the retort in which it is generated into the vessel wherein the
re-action takes place; but, if desired, this vapour may be condensed in a proper
vessel and re-volatilized.
This invention broadly stated consists in combining aluminous material to be
reduced and a reducing agent, both in vapour form, in a proper chamber, the said
vapours being generated in two separate retorts or in two separate sets of retorts.
Having described the nature of the said invention and the manner of
carrying it into practical effect as communicated to me as aforesaid I would have
it understood that what is considered to be novel and original and is therefore
claimed as the invention secured to me under the Letters Patent first hereinabove
in part recited is
1. Extracting metallic aluminium from its ores or compounds by mutual reaction
in a heated chamber or receiver of the vapour of a volatile compound of aluminium
and sodium vapour substantially as described.
2. The process of producing metallic aluminium which consists in simultaneously
generating sodium vapour and a volatile compound of aluminium in two separate
vessels or retorts and in mingling the vapours thus obtained in a third vessel
wherein they re-act upon each other substantially as described.
3. The process of producing metallic aluminium which consists in mingling in a
chamber or receiver, sodium vapour and a compound of aluminium also in vapour
form, said sodium vapour being generated by heating in a separate vessel or retort
a mixture of a sodium compound with charcoal or other reducing agent and said
aluminous vapour being simultaneously produced in another vessel or retort from
aluminous material
4. The process of producing metallic aluminium which consists in simultaneously
generating sodium vapour and the chloride or fluoride of aluminium also in vapour
form in two separate vessels or retorts and in mingling the two vapours thus
obtained in a third vessel wherein they re-act upon each other substantially as
described.

page_text: 5. The process of producing metallic aluminium which consists in simultaneously
generating sodium vapour and the double chloride of aluminium and sodium also
in vapour form, in two separate vessels or retorts and in mingling the two vapours
thus obtained in a third vessel wherein they re-act upon each other substantially
as described.
6. The process of extracting metallic aluminium from its ores or compounds which
consists in converting such aluminous material into the form of vapour by heating
it in a vessel or retort with chloride of sodium and carbonaceous material and at
the same time subjecting it to the action of a stream of chlorine gas and in
mingling in a chamber or receiver the vapour of the double chloride of aluminium
and sodium thus obtained with sodium vapour simultaneously generated in another
vessel or retort by heating a mixture of carbonate of soda and carbon substantially
as described.
In witness whereof I the said Henry Arthur Gadsden have hereunto set my hand
and seal this sixteenth day of April in the year of Our Lord one thousand eight
hundred and eighty four
HENRY A. GADSDEN (LS.)