IMPROVEMENTS IN THE MODE OF AND APPARATUS FOR SEPARATING IMPURITIES FROM AURIFEROUS ORES AND IN THE TREATMENT OF SUCH ORES
Year: 1880

page_text: LETTERS PATENT to Edward Griffith Brewer, of 33, Chancery Lane, in the
County of Middlesex, for an Invention of "IMPROVEMENTS IN THE MODE
OF AND APPARATUS FOR SEPARATING IMPURITIES FROM AURIFEROUS ORES
AND IN THE TREATMENT OF SUCH ORES." A communication from abroad by
Thomas Alva Edison, of Menlo Park, in the State of New Jersey, United
States of America.
PROVISIONAL SPECIFICATION left by the said Edward Griffith Brewer at
the Office of the Commissioners of Patents on the 20th October 1880.
EDWARD GRIFFITH BREWER, of 33, Chancery Lane, in the County of Middlesex.
"IMPROVEMENTS IN THE MODE OF AND APPARATUS FOR SEPARATING IMPURITIES
FROM AURIFEROUS ORES AND IN THE TREATMENT OF SUCH ORES." (A. com-
munication from abroad by Thomas Alva Edison, of Menlo Park, in the State of
New Jersey, United States of America.)
By careful microscopic and chemical tests the inventor has found that the gold,
or the greater portion thereof, in the so called auriferous sulphurets exists as
free gold therein, either comparatively coarse, i.e., in small lumps or flakes, or in
a very finely comminuted state, sometimes the surface, but it only being affected by
the sulphur, though then sufficiently to prevent casy or economic amalgamation.
The inventor has also found that while sulphuret of iron and ferrous oxide are
generally considered to be non-magnetic, they are in fact slightly magnetic, so
much so that they may be magnetically affected, especially when subjected at a
small distance to the action of powerful magnets, such as may be produced by
currents from large magneto or dynamo-electric machines.
With these discoveries as a basis the inventor has devised a process by which
the ferrous compounds constituting the greater portion of the "gangue" of the so
called auriferous sulphurets may be easily and economically removed from the
auriferous portion.

page_text: '
By microscopic and other tests it is first determined whether the gold be fine
or comparatively coarse, that only being called fine when the gold therein is found
to be as fine as or finer than the degree of comminution to which it is practicable to
reduce the rock or "gangue" by grinding or stamping.
If the gold be found to be coarse the material is simply ground, the iron remaining
in the shape of sulphuret of iron.
If the gold be fine the material is roasted and ground, this process changing the
sulphuret of iron to ferrous oxide.
The material is then passed through the series of magnetic separators hereinafter
referred to.
The magnets therein being of great strength due to the large currents from
powerful magneto or dynamo-electro machines used therewith act magnetically
upon the iron compounds, drawing them out of the mingled material and leaving
the remainder to be treated by some appropriate process in order to free the gold
from any impurities which may exist.
The inventor has found that by this course of treatment sulphurets, even when
of very low "gradu" may be readily and economically treated, and the gold
profitably separated therefrom.
The inventor has a device for separating magnetic and non-magnetic substances,
consisting essentially of a magnet, past whose poles fall the mingled substances, the
attraction of the magnet acting to alter the path of the inagnetic substance, drawing
it out and away from the non-magnetic portion, the magnetic and non-magnetic
substances falling into different receptacles.
Another part of the Invention in this case relates to improvements upon the
above described device, and consists in the feature more particularly hereinafter
epecified. In this Invention V shaped electro magnets are used, made up of one or
of several series of coils.
Where several series of coils are used their polar faces or extensions are united
to form one polar face or extension for one polarity, the polar face being placed at
right angles to the flow of the inaterial to be treated.
The magnetic material is acted on consequently by both poles. As the first
draws it out of its path, if the second were in the same plane relatively to the flow
of material, it would act on the material at a shorter distance than the first, and
would possibly attract the material to itself.
To avoid this it is better to place the active faces of the polar extensions in
different planes relatively to the flow of material, the second being placed at the
rear of the first, a distance approximately equal to the distance the first draws
the magnetic material out of its path.
From the fact that often a particle or particles of magnetic substances are not
drawn out of their path sufficiently, and fall with the non magnetic substances it
is preferable that the inaterial be subjected to the action of the separator several
times in order to ensure thorough separation.
As some portion of the substance to be treated is more magnetic than another,
this inore magnetic portion is apt to be drawn out of its path and separated by the
first separator; moreover if the magnets be too near the path of the very magnetic
material they would be apt to draw such material to themselves, which clinging
thereto would soon clog the magnets, thus constantly extending their poles; hence
the magnets of the first separator are placed at some distance from the path of
the material.
In order then to act equally on the less magnetic portion is is preferable that the
next set of magnets be placed somewhat nearer the path of the falling material,
and so with each successive separator of the series.
To accomplish this several, preferably three, separators are arranged in series,
somewhat in echelon, so that the portion which passes into the non-magnetic
receptacle of the first passes immediately to the second separator, and so on through

page_text: the series, the magnetic receptacles of all the series leading to a common delivery
shoot.
Combined with this series is a suitable hopper and sieve and elevator for carrying
the sifted material up and delivering it to the first separator of the series.
The construction of the individual separator and the series possesses advantages
beyond those noted, especially for use in an improved process of treating so called
auriferous sulphurets.
It is evident that the use of a separator thus constructed is not limited to the
separation of magnetic substances from auriferous ores, but may be used wherever
it is desired to separate mingled magnetic and non-magnetic substances.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Griffith Brower in the Great Seal Patent Office on the 20th
April 1881.
EDWARD GRIFFITHI BREWER, of 33, Chancery Lane, in the County of Middlesex.
"IMPROVEMENTS IN THE MODE OF AND APPARATUS FOR SEPARATING IMPURITIES
FROM AURIFEROUS ORES AND IN THE TREATMENT OF SUCH ORES." (A com-
munication from abroad by Thomas Alva Edison, of Menlo Park, in the State of
New Jersey, United States of America.)
By careful microscopic and chemical tests the inventor has found that the gold,
or the greater portion thereof, in the so-called auriferous sulphurets exists as free
gold therein, either comparatively coarse, i.c., in small lumps or flakes, or in a very
finely comminuted state sometimes the surface, but it only being affected by the
sulphur, though then sufficiently to prevent easy or economic amalgamation.
The inventor has also found that while sulphuret of iron and ferrous oxide are
generally considered to be non-magnetic, they are in fact slightly magnetic, so
much so that they may be magnetically affected, especially when subjected at a
small distance to the action of powerful magnets, such as may be produced by
currents from large magnets or dynamo-electric machines.
With these discoveries as a basis the inventor has devised a process by which
the ferrous compounds constituting the greater portion of the "gangue" of the so-
called auriferous sulphurets may be easily and economically removed from the
auriferous portion.
By microscopic and other tests it is first determined whether the gold be fine
or comparatively coarse, that only being called fine when the gold therein is found
to be as fine as or finer than the degree of comminution to which it is practicable
to reduce the rock or "gangue" by grinding or stamping.
If the gold be found to be coarse the material is simply ground, the iron
remaining in the shape of sulphuret of iron.
If the gold be fine the material is roasted and ground, this process changing the
sulphuret of iron to a ferrous oxide.
The material is then passed through the series of magnetic separaters hereinafter
referred to.
The magnets therein being of great strength, due to the large currents from
powerful magneto or dynamo electric machines used therewith, act magnetically
upon the iron compounds, drawing them out of the mingled material and leaving
the remainder to be treated by some appropriate process in order to free the gold
from any impurities which may exist.
The inventor has found that by this course of treatment sulphurets, even when
of very low grades, may be readily and economically treated, and the gold
profitably separated therefrom.
The inventor has a device for separating magnetic and non-magnetic substances,
consisting essentially of a magnet, past whose poles fall the mingled substances,
the attraction of the magnet acting to alter the path of the magnetic substance,
drawing it out and away from the non-magnetic portion, the magnetic and non-
magnetic substances falling into different receptacles.
Another part of the Invention in this case relates to improvements upon the
above described device, and consists in the features more particularly hereinafter
specified.
In this Invention U shaped electro magnets are used, made up of one or of
several series of coils.
Where several scries of coils are used, their polar faces or extensions are united
to form one polar face or extension for one polarity, the polar face being placed at
right angles to the flow of the material to be treated.

page_text: The magnetic material is acted on consequently by both poles. As the first
draws it out of its path, if the second were in the same plane relatively to the flow
of material, it would act on the material at a shorter distance than the first, and
would possibly attract the material to itself.
To avoid this it is better to place the active faces of the polar extensions in
different planes relatively to the flow of material, the second being placed at the
rear of the first, a distance approximately equal to the distance the first draws
the magnetic material out of its path.
From the fact that often a particle or particles of magnetic substances are not
drawn out of their path sufficiently and fall with the non-magnetic subtsances,
it is preferable that the material be subjected to the action of the separator several
times in order to insure thorough separation.
As some portion of the substance to be treated is more magnetic than another,
this more magnetic portion is apt to be drawn out of its path and separated by
the first separator; moreover if the magnets be too near the path of the very
inagnetic material they would be apt to draw such material to themselves, which
clinging thereto would soon clog the magnets, thereby constantly extending their
poles; hence the magnets of the first separator are placed at some distance from the
path of the material.
In order then to act equally on the less magnetic portion, it is preferable that
the next set of magnets be placed somewhat nearor the path of the falling material,
and so with each successive separator of the series.
To accomplish this several, proferably three, separators are arranged in series,
somewhat in echelon, so that the portion which passes into the non-magnetic
receptacle of the first passes immediately to the second separator, and so on
through the series, the magnetic receptacles of all the series leading to a common
delivery shoot.
Combined with this series is a suitable hopper and sieve and elevator for carrying
the sifted material up and delivering it to the first separator of the series.
The construction of the individual separator and the series possesses advantages
beyond those noted, especially for use in an improved process of treating so-called
auriferous sulphurets, which forms a portion of this Invention.
It is evident that the use of a separator thus constructed is not limited to the
separation of magnetic substances from auriferous ores, but may be used wherever
it is desired to separate mingled magnetic and non-magnetic substances.
Such part of the Invention as is capable of illustration is shewn in the
accompanying Drawings, in which
Figure 1 represents in perspective view a series of separators and accessories
mounted in a suitable framing.
Figure 2, a single hopper and magnet in detail; Figure 3, a series of magnetic
separators in section taken on line x, x, of Figure 1.
H, H, H, shews the framing, which may be of any suitable kind, in which are
secured the separators 1, 2, 3, each consisting essentially of a hopper and magnet,
as A M, B M', and CM".
The material to be treated is first fed into a hopper F, whence it passes into
a sieve, as all lumps, stones, &c., should be separated from the material to be
treated.
An elevator L conveys the material to the hopper A of the first separator,
whence it falls in front of the magnet M.
Below M is a hopper B receiving the non-magnetic portion and passing it before
the second magnet M¹, the magnetic portion falling into B', and thence into the
waste shoot E.
Below M' is a similar hopper C passing the non-magnetic material before M',
and the passage C¹ passing the magnetic portion into the waste shoot E.
This construction and relation are repeated until as many separators as may be
desired are arranged in the series.

page_text: It will be noticed that each succeeding magnet is set nearer the path of the
material than its predecessor in the series; for instance, M" is nearer such path
than M¹, and M' than M.
Motion is communicated to various portions of the series by means of belts and
the pulleys P, P, etc.
When desired it is evident that the elevator may be dispensed with, and the
sifted material be conveyed to the hopper of the first separator in any convenient
manner.
Having now described the nature of the said Invention and in what manner the
same is to be performed I declare I claim,—
First. In an electro magnetic separator, a magnet, a series of magnets whose
poles or polar extensions or faces are in different planes relatively to the path of the
material to be treated, substantially as set forth.
Second. The combination of a series of magnetic separators, substantially such
as described, arranged to act successively upon the same stream of material,
substantially as set forth.
Third. The combination of a series of magnetic separators, substantially such as
described, each one of the series being arranged nearer the path of the material to
be acted on than its predecessor in the series, substantially as set forth.
Fourth. The combination with a series of magnetic separators arranged to act
consecutively upon a stream of material of a single waste shoot and a passage
thereto from each separator, substantially as set forth.
Fifth. The combination of a sieve, an elevator, a series of separators, and a single
waste shoot, substantially as set forth.
Sixth. The method of treating so-called auriferous sulphurets, which consist in
reducing them to powder and then subjecting the resulting material (either raw
or roasted) to the action of a magnetic separator, substantially as set forth.
In witness whereof, I, the said Edward Griffith Brewer, have hereunto set
my hand and seal, this Sixteenth day of April, in the year of our Lord
One thousand eight hundred and eighty one.
דדות
E. G. BREWER. (..)