Improvements in Magnetic Separators.
Year: 1898

page_text: Date of Application, 29th Mar., 1898
Complete Specification Left, 14th Jan., 1899-Accepted, 18th Feb., 1899
PROVISIONAL SPECIFICATION.
Improvements in Magnetic Separators.
I, ALEXANDER MELVILLE CLARK, of the Firm of A. M. & Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Chartered Institute
of Patent Agents, do hereby declare the nature of this invention (a communica-
tion to me by The Metallurgische Gesellschaft, A.G., of 14, Junghofstrasse,
Frankfort-on-Main, in the Empire of Germany) to be as follows;―
This invention has for object mainly the treatment of weak magnetic bodies
according to the process described in Patents Nos. 4805 and 4806 of 1896, and it
consists in improvements of such nature as to facilitate the treatment of substances
which could be separated with the old apparatus, and enable such substances to be
separated of which the magnetic properties are too weak to admit of being utilized
heretofore for effecting the separation of the said substances. Thus, for example,
it was not possible heretofore to utilise for the purpose of separation the very weak
magnetism of monazite, zinc blende, and copper pyrites, and other substances
whose para-magnetism can be ascertained by the instruments of Faraday, although
larger and more effective iron massés were employed as the cores of the magnets.
The operation of the new machine is such that even dia-magnetic bodies can be
influenced in such a way as to tend to assist the separation thereof from the para-
magnetic bodies.
In order to understand the mode of operation of the machine, reference is made
to the well known law that para-magnetic bodies have a tendency in a magnetic
field to move from a point of weak concentration of the magnetic lines of force
to the point of highest concentration of these lines of force. In the magnets of
the machines herein described, the place of highest concentration of the lines of
force is the common plane of the two edges of the pole pieces.
The new apparatus combines the following properties:-The edges of the pole
pieces need only to be arranged so far apart as is necessary to allow of the passage
of the magnetic particles between them, so that by this close juxta-position, a very
highly concentrated magnetic field is produced. All raising of the magnetic
particles, that is to say, the overcoming of the force of gravity, is rendered unneces-
sary; the magnetic particle moves along the place of greatest concentration and
is acted upon during the whole of this period.
In the accompanying drawings which illustrate one form of construction of the
new machine, Figure is a cross sectional elevation, and Figure 2 is a front
elevation of the machine. Figure 3 is a front view of the edge of the lower pole
piece on a larger scale, and Figure 4 is an end view of Figure 3.
Of the two magnets A and B which are of wedge shape pointed form, the lower
magnet B has the edge of its pole piece directed at a steep upward inclination,
while the pole piece of the upper magnet A is almost horizontal. The edges of the
two pole pieces are adjusted relatively to each other in such a manner that the edge
of the magnet B is situated below and slightly laterally of the edge of the magnet A,
as shown in Figure 1, and on the edge of the magnet B there is adjustably mounted
a thin separating plate G. The band D which runs around the front face of the

page_text: upper magnet A brings the previously comminuted material supplied to it by
hopper E and roller F, in a uniform thin layer as far as the pole edge of this
magnet, where it drops and in dropping is caused to describe a parabola under the
combined influences of the attraction of gravity and of the impulse produced by
the motion of the conveyor band. The separating plate G is so adjusted that if
the electro magnets were not energized, the matters conveyed by the band D) would
fall exactly and just over this plate and drop down on the right hand side of the
lower magnet in Figure 1. In this movement the material passes along and in
immediate proximity to the plane of highest concentration of the lines of force
and over its whole extent. If this field be produced by energizing the electro
magnets, the weak para-magnetic particles contained in the material charged into
the machine will be caused to move out of the parabolic path of the non-magnetic
particles and into the field of highest concentration of the lines of force, and will
consequently be caused to describe a steeper parabolic path than the non-magnetic
constituents, so that they cannot pass over the separating plate G but are compelled
to fall down in front of the same, (that is to say, to the left of the magnet pole
piece B in Figure 1) and between the edges of the two pole pieces. Without
restricting the use of the machine to any particular para-magnetic bodies, it may
be stated that with the aid of this machine the following may be separated. As
examples, monazite from quartz; zinc blende from galena; and copper pyrites
from calcareous spar; in which mixtures monazite, zinc blende and copper pyrites
are the extremely weak para-magnetic substances, whilst quartz, galena and
calcareous spar are non-magnetic.
If in addition to very weak para-magnetic and non-magnetic bodies, very
strongly dia-magnetic bodies are contained in the mixture the presence of the latter
will not interfere in any way with the separating operation, but will rather facilitate
it. In moving along over the plane of highest concentration of the magnetic lines
of force, the dia-magnetic bodies will be repelled therefrom and will therefore
describe a still flatter parabolic path than the entirely non-magnetic constituents.
They will therefore pass still more easily over the separating plate than the non-
magnetic bodies. This would be the case for example in the separation of the
mixture of zinc blende, quartz and native bismuth, or of zinc blende and native
bismuth alone. If in the mixture charged into the machine there are
any more strongly para-magnetic substances such as spathic iron ore,
hematite, these more susceptible substances might adhere to the pole
piece edges of the machine, were it not that in the case of the upper magnet A
their removal is effected by the conveyor band D), whilst in this case the lower
magnet must be provided with a special stopping band H which runs (like the
charging band D round the upper pole piece edge) round the lower pole piece edge
as indicated in Figures 3 and 4 the separating plate G being provided with an
aperture through which the band H passes. The separating plate may be
omitted if the pole piece edge is made sufficiently sharp and is adjusted with
sufficient accuracy.
Doted this 20th d...
1000

page_text: of Patent Agents, do hereby declare the nature of this invention (a communica-
tion to me by The Metallurgische Gesellschaft, A.G., of 14, Junghofstrasse,
Frankfort-on-Main, in the Empire of Germany,) and in what manner the same
is to be performed to be particularly described and ascertained in and by the follow-
ing statement:
-
This invention has for object mainly the treatment of weakly-magnetic sub-
stances according to the method described in Patents Nos. 4805 and 4806 of 1896,
and it consists in improvements whereby to facilitate the treatment of substances
which could be separated with the old apparatus and to enable the separation to
be effected of substances whereof the magnetic properties are too weak to have
admitted of being separated by the means heretofore in use. Thus, for example,
it was not possible heretofore to utilize for the purpose of separation the very weak
magnetism of monazite, zinc blende, copper pyrites, and other substances (whose
para magnetism can be ascertained by the instruments of Faraday) notwithstanding
were employed as the cores of the
5 that larger and more effective iron masses
magnets.
The operation of the machine of this invention is such that even dia-magnetic
bodies can be influenced in such a way as to tend to assist the separation thereof
from the para-magnetic bodies.
In order to understand the mode of operation of this machine reference is made
to the well known law that para-magnetic bodies in a magnetic field have a ten-
dency to move from a point of weak concentration of the magnetic lines of force
to the point of highest concentration of these lines of force. In the magnets of the
machines herein described, the place of highest concentration of the lines of force
5 is the plane common to the two edges of the pole pieces.
The new apparatus combines the following properties:-The edges of the pole
_pieces need only to be arranged so far apart as is necessary to allow of the passage
of the magnetic particles between them, so that by this close juxtaposition a very
highly concentrated magnetic field is produced. The raising of the magnetic
30 particles in opposition to the force of gravity is rendered unnecessary since the
magnetic particle falls along the place of greatest concentration and is influenced
during the whole of this movement.
35
°
In the drawings accompanying the Provisional Specification (which illustrate
one form of construction of the new machine) Figure 1 is a cross-sectional elevation
and Figure 2 is a front elevation of the machine. Figure 3 is a front view of one
of the pole pieces of the lower magnet on a larger scale and Figure 4 is an end view
of Figure 3.
A and B are two magnets provided with wedge-shape pole pieces the lower
magnet B having its pole pieces at a steep inclination with the edges directed up-
40 wards while the pole pieces of the upper magnet A are almost horizontal. The
edges of the pole pieces of the two magnets are so adjusted relatively to each other
that the polar edges of the magnet B are situated below and slightly laterally of
the polar edges of the magnet A as shewn in Figure 1 and on each of the polar
edges of the magnet B there is adjustably mounted a thin separating plate G.
45 Bands D which run over the surfaces and around the edges of the poles of the upper
magnet each bring the previously comminuted material supplied thereto by
hoppers E and rollers F in a uniform thin layer as far as the polar edge of this
magnet, where it drops and in dropping is caused to describe a parabola under the
combined influences of the attraction of gravity and of the impulse produced by
50 the motion of the conveyor band. The separating plate G is so adjusted that if
the electro-magnets were not energized, the matters conveyed by the band D would
fall exactly and just over this plate and drop down on the right hand side of the
lower magnet in Figure 1. In this movement the material passes along or in
immediate proximity to the plane of highest concentration of the lines of force and
55 over its whole extent. If this field be produced by energizing the electro-magnets
the weak para-magnetic particles contained in the material will be caused to move

page_text: out of the parabolic path of the non-magnetic particles and into the field of highest
concentration of the lines of force and will consequently be caused to describe a
steeper parabolic path than the non-magnetic constituents, so that they cannot
pass over the separating plate G but are compelled to fall down in front of the
same (that is to say to the left of the pole piece of magnet B in Figure 1) and 5
between the polar edges of the two magnets. Without restricting the use of the
machine to any particular para-magnetic substances, it may be mentioned for
instance that by means of this machine the following substances may be separated:
viz., monazite from quartz, zinc blende from galena, and copper pyrites from
calcareous spar; in which mixtures monazite, zinc blende, and copper pyrites are 1
the extremely weak para-magnetic substances whilst quartz, galena, and calcar
spar are non-magnetic.
If in addition to very weak para-magnetic and non-magnetic substances very
strongly dia-magnetic substances are contained in the mixture the presence of the
latter will not interfere in any way with the operation of separation but will rather
facilitate it. In moving over the plane of highest concentration of the magnetic
lines of force the dia-magnetic substances will be repelled therefrom and will there
fore describe a still flatter parabolic path than the entirely non-magnetic con-
stituents. They will therefore pass still farther over the separating plate G than
the non magnetic bodies. This would be the case for example in the separation 2
of zinc blende, quartz, and native bismuth, from a mixture of those substances in
the separation of zinc blende and native bismuth alone. If in the mixture there
are any more strongly para-magnetic substances such as spathic iron ore, hematite,
these more susceptible substances might adhere to the polar edges of the machin
were it not that their removal from the upper magnet A is effected by the conveyor 2
band D whilst in this case the lower magnet must be provided with strip ng
bands H which run (like the charging bands D round the polar edges of the uppe
magnet) round the polar edges of the lower magnet as indicated in Figures 3 and
each of the separating plates G being provided with an aperture h through w
the band H passes. The separating plate may be omitted if the polar edges of the
lower magnet are made sufficiently sharp and are adjusted with sufficient accuracy
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what I
claim is-
1. An apparatus for separating magnetic substances from weak magnetic
non-magnetic admixtures wherein the polar edge of the one magnet is arra iged
higher than that of the other magnet and the mixture is supplied to the polar edge
of the upper magnet in such a manner that the non-magnetic substances fall freely
on one side of the plane common to the polar edges of the two magnets which coin
cides with the maximum concentration of the magnetic lines of force whilst the
magnetic particles are drawn into this plane and fall down on the other side of the
lower magnet.
か
2. A particular form of construction of the apparatus specified in Clain 1
in which the lower magnet is arranged almost vertical and the upper magnet is
arranged almost horizontal with its polar edge slightly out of the vertical thr agh 4
the edge of the lower magnet and the mixture is conveyed upon a conveyor band
which moves round the polar edge of the upper magnet substantially as described.
Dated this 14th day of January 1899
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.