Method or Process for Obtaining Aluminium.
Year: 1889

page_text: Date of Application, 3rd Sept., 1889-Accepted, 5th Oct., 1859
COMPLETE SPECIFICATION.
Method or Process for Obtaining Aluminium.
I, HERBERT JOHN ALLISON, of 52 Chancery Lane, London, in the County of
Middlesex, Patent Agent, do hereby declare the nature of this invention (which has
been communicated to me from abroad by "The Great Western Aluminium
Smelting & Refining Co." (Incorporated), of Denver, Colorado, United States of
America), and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
My invention relates to a new and useful method or process for the production of
metallic aluminium either in condition sufficiently pure for ordinary uses or as alloyed
with any desired metal or metals.
Its object is to furnish for such production a simple, readily and easily practised,
efficient and reliable method, and adapted to produce the metal aluminium from
aluminous ores as a commercial product so economically as to warrant its practical
use in many relations in the arts and manufactures where now, cheaper metals, not
possessing its merits, advantages, and adaptabilities are used.
To these ends my invention consists in a process of treating any of the aluminous
fluorides while fused with a compound readily disassociating at a temperature below
the fusing point of the aluminous fluoride and having an element or elements of such
high affinity for fluorine, that it or they, at the moment of disassociation, or while in
statu nascendi unite immediately with such element or elements of the aluminous
fluorides as are in combination with the aluminium, displacing and leaving the latter
free, a process for the production of the metal by substitution, as it may be termed,
as hereinafter described and claimed.
In practicing my process the aluminous base used, may be the ordinary fluoride of
aluminium, either that found as a natural product, such as fluolite, or that formed
from the oxide or hydroxide or other aluminous compound, or such base may be a
double fluoride of aluminium and an alkaline metal, such as cryolite or A12-F1-6 Na Fl.
While either may be used as the base, it is preferable to mix them and use as the base
a mixture of one part of the single fluoride to two parts of the double fluoride of
aluminium and an alkaline metal for the reason that the sodium or other alkaline
metal in the double fluoride forms a suitable fluxing material, enabling the reduction
process to be carried on without the addition of extraneous fluxes, while in such
compound the other elements are present in the combining proportions proper for the
reagents to be used as hereinafter specified.
The base used is, fed into or placed within any suitable furnace or crucible
containing a bath of fused metal and is then itself fused upon or over such bath or
in such relation thereto that the fused material may flow into or upon such bath. The
base thus fused and in the bath is then treated with a reagent, whose elements
disassociate at a temperature lower than that of the fused base, and having an element
of greater affinity for fluorine than has the aluminium.
Among such reagents are the sulphides of silicon and of boron and the hydrides
of the same and the carbo-hydrides thereof, and the nitrides of the same.
The mode of the application of these reagents will vary somewhat with the
furnace or crucible used and the particular reagent employed. The application may
be by passing the reagent through the fused mass in a gaseous state when it assumes
or can be made to assume such state; or it may be by forcing the reagent finely
comminuted through the fused mass by a jet of hydrogen or nitrogen or other fluid
not containing oxygen or by a jet of fluid which, while containing oxygen, does not
part therewith to, or in the presence of the other elements, as carbon monoxide for
instance; or the reagent may have been mingled with the aluminious fluoride while
the latter was still in a solid state, the essential thing being that the aluminious base

page_text: and the reagent should be in proper relation to each other for the operation of their
affinities and for changes of combination at the moment of disassociation of the
elements of this reagent.
In the reactions that follow, all the original combinations are broken up and the
elements, excepting aluminium, enter into new ones, the aluminium being replaced in
its former combinations by other elements and left in a free metallic state. For
instance, if silican sulphide were the reagent employed, its silicon at the moment of
disassociation attacks the fluorine and combines therewith to the exclusion of the
aluminium, there being as resultants, besides other elements or compounds, silican
fluoride and free aluminium, the silican being substituted for the aluminium in the
fluorine compounds. The same reaction and results follow the use of either of the
sulphides, hydrides, or carbo-hydrides of silican or boron, they being generic
equivalents in the process noted.
While in the fused condition the freed aluminium should be protected from contact
with air or other oxygen yielding material. While in the bath the slag formed in
part, at least of the sodium from the double fluoride does this, but it is also preferable
that the process should be carried on in a furnace from which air is excluded as
thoroughly as possible.
When it is desired to obtain the aluminium in a practically or commercially pure
state the metallic bath referred to should be of fused aluminium itself, otherwise, it
should be of such metal as it is desired to alloy the reduced aluminium with.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. The process of obtaining the metal aluminium herein described, consisting in
treating a fused aluminous fluoride or fluorides, while in a molten metallic bath and
protected from oxidizing agents with a reagent, whose elements disassociate at a
temperature below the fusing point of the aluminious fluoride or fluorides, and having
an element of such affinities that it displaces the aluminium in the fluoride or
fluorides but having no element adapted to unite with the aluminium, substantially as
set forth.
2. The process of obtaining aluminium by treating a base of fused aluminious
fluoride or fluorides, while in a bath of molten metal and protected from oxidizing
agents with a sulphide of silicon or equivalent reagent, substantially as set forth and
described.
Dated this 3rd day of September A.D. 1889.
ALLISON BROS.,
Agents for the Applicant.