A Process for Obtaining Metals in Molten Condition from their Fused Oxides by Electrical Action.
Year: 1890

page_text: Date of Application, 24th July, 1890
Complete Specification Left, 20th Apr., 1891-Accepted, 8th Aug., 1891
PROVISIONAL SPECIFICATION.
[Partly communicated. from abroad by FREDERICK WILLIAM MATTHIESSEN, of
La Salle, Illinois, United States of America.]
A Process for Obtaining Metals in Molten Condition from their Fused
Oxides by Electrical Action.
I, ALFRED HUTCHINSON COWLES, of Cleveland, Ohio, United States of
America, Engineer but at present of First Avenue Hotel Holborn in the County
of Middlesex do hereby declare the nature of this invention to be as follows:-
This invention relates to a continuous process for obtaining by electrical action
metals such as aluminium, magnesium and others in molten condition from their
oxides when these are in a state of fusion along with suitable fluxes, to the selection
of which this invention more particularly relates. The flux applicable for any
particular metallic oxide may be selected from the following:-Some anhydrous
haloid salt of the metal itself, a salt of some alkaline metal or alkaline earth metal,
or mixtures or compounds of such salts, subject to the following conditions:-The
alkaline or alkaline earth metals the salts of which are used should be more electro
positive than the metal whose oxide is to be reduced :-The salts should be such
as to flux or dissolve the oxide, and to be, when fused along with the oxide, of less
density than the metal to be obtained from the oxide:-also the flux should remain
liquid within a sufficient range of temperature above the melting point and below
the volatilising point of the metal to be obtained. Fluxes, selected according to
these conditions, being fused in a crucible or vessel of carbon or other such material
as will not be acted on by the molten flux, and this vessel being provided with an
anode and a cathode (which may both be of carbon) connected to the terminals of
a dynamo-electric machine or other source of electricity, the metallic oxide to be
reduced can be fed in continuously while the fused contents of the vessel are subject
to an electrical current of sufficient tension, and the oxide will be reduced, the
oxygen being separated, and the metal sinking to the bottom whence it can be.
allowed to flow continuously, or whence it can be removed at intervals.
Dated this 24th don of Tule 1900
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
A Process for Obtaining Metals in Molten Condition from their Fused
Oxides by Electrical Action.
I, ALFRED HUTCHINSON COWLES, of Cleveland, Ohio, United States of
America, Engineer, but at present of First Avenue Hotel, Holborn, in the County
of Middlesex, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
This invention relates to a continuous process for obtaining by electrical action
metals such as aluminium, magnesium, and others, in molten condition, from their
oxides, when these are in a state of fusion along with suitable fluxes, to the selection
and electrical melting of which this invention more particularly relates. The flux
applicable for any particular metallic oxide may be some anhydrous haloid salt of
the metal itself, or a salt of some alkaline metal or alkaline earth metal or of
mixtures or compounds of such salts, the flux being selected subject to the following
conditions -The alkaline or alkaline earth metals, the salts of which are used

page_text: should be such that the energy required to reduce the oxide at the temperature of
the bath should be less than that required to reduce a chemically equivalent quantity
of the flux.
If carbon be used as an anode, then the energy required to reduce the oxide
producing carbonic acid gas and metal should be less than that required to
reduce a chemically equivalent quantity of the flux. The salts should be such
as to flux or dissolve the oxide, and to be, when fused along with the oxide, of less
density than the metal to be obtained from the oxide; also the flux should remain
liquid within a sufficient range of temperatures above the melting point and below
the volatilising point of the metal to be obtained. Fluxes selected according to
these conditions, being maintained electrically fused in a crucible or vessel of
carbon or other such material as will not to be acted on by the molten flux, and
this vessel being provided with an anode and a cathode (which may both be of
carbon) connected to the terminals of a dynamo electric machine or other source of
electricity, the metallic oxide to be reduced can be fed in continuously while the
fused contents of the vessel are subject to an electric current of sufficient tension
to keep the contents of the crucible both fused and electrolised; and the oxide will
be reduced, the oxygen being separated and the metal sinking to the bottom whence
it can be allowed to flow continuously, or whence it can be removed at intervals.
As an example, I take as a flux cryolite which I fuse by electrical heat in a pot
or crucible having thick walls and bottom of carbon constituting the cathode, a
block of carbon immersed to some depth in the fused cryolite forming the anode. I
feed the pot with alumina which becomes fused or fluxed by the molteu cryolite and
decomposed in the bath, the aluminium sinking to the bottom of the pot whence it
can be run off continuously, or from time to time removed. The electricity supplied
should be in quantity and of voltage sufficient to heat the bath to fusion and
maintain it in fusion. The fall in potential between the anode and the cathode
necessary for decomposition of the alumina is about three volts, but the current
requires suplus electro-motive force to carry through the bath the current necessary
for producing the required heat.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is :-
The herein described process for obtaining metals in molten condition from their
fused oxides by electrical action, the said oxides being fused along with fluxes
selected according to the conditions herein set forth.
Dated this 20th day of April 1891
ABEL & IMRAY,
Agents for the Applicant.