Improvements relating to the Separation of Magnetic from Non- magnetic Substances, and to Apparatus therefor.
Year: 1890

page_text: COMPLETE SPECIFICATION.
[Communicated from abroad by CLINTON MANNING BALL, of Troy, County of
Rensselaer, State of New York, Electrical Engineer, and SHELDON NORTON,
of Hokendaugua, County of Lehigh, State of Pennsylvania, Mechanical Engineer,
both in the United States of America.]
Improvements relating to the Separation of Magnetic from Non-
magnetic Substances, and to Apparatus therefor.
I, HENRY HARRIS LAKE of the firm of Haseltine, Lake & Co., Patent Agents,
45 Southampton Buildings 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 new method or process for separating iron or its crushed
ore from the impurities with which such are generally found associated, and while
the invention is capable of being carried into practical effect in the dry way it is more
particularly adapted to carry out the separation in the wet way, in which the ore and
gangue are mingled with water previous to separation.
Briefly my invention consists in passing the ore and gangue through a magnetic
field, and when emerging therefrom subjecting the adhering ore to centrifugal action,
while interposing a deflector in the tangential path of the ore to separate the less
magnetic from the more highly magnetic portions of the separated product and
further in subjecting the material to the action of a current of air, opposite in
direction to that taken by the material under the centrifugal impulse. The invention
further consists in the specific steps of the process and in the apparatus employed to
carry such process into effect all substantially as hereinafter fully described and
claimed.
In the drawing is shown a longitudinal vertical section of a form of separator
constructed in accordance with the principles of this invention and capable of operation
in either the wet or the dry way.
I construct the apparatus in the form of a chest having the sides 1 and 2, top 3,
end hopper shaped botton 4. In the upper portion of this structure I place a
revolving drum 5 and shaft 6, which latter I prefer to make hollow, so as to give access
to the interior of the drum, the shaft being laterally perforated inside the drum for
conveniently introducing the electrical conductors. The drum is preferably made of
non-magnetic material, such for instance, as brass or copper or more preferably still
of an electrically non-conductive material such as indurated fibre, hard rubber, etc.
Inside the drum and upon its shaft is suspended a cylindrical segment of iron 7,
having the sleeve 8, through which the shaft passes, and forming the point of
suspension for the segment. Radiating from the lower surface of the segment 7
are a number of magnet cores 9, which extend almost into contact with the inner
surface of the drum. These cores are wound with insulated wire and by
preference are connected into the exciting circuit in such way as to make the
successive poles alternately N. and S. The weight of the structure 7, 8, 9 is such
that the drum may be rapidly rotated around the magnet and out of contact there-
with without disturbing the normal position of the magnetic structure.
While I have given preference to the alternating character of the poles of the
magnetic system I wish to state that this is not essential to the carrying out
of the process herein described.
In the top of the structure 1 arrange a hopper 10 for the introduction of the ore
and gangue, and below this I place an apron 11, which guides the ore and gangue
into close proximity to the drum 5. A water tank 12 may be arranged to be supplied
with water from any suitable source, such, for instance, as the pipe 13 and discharge

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water at the mouth 14 so as to fall downwardly in an even stream over the apron 11.
The hopper bottom 4 rises up to a point near the drum 5 on the side opposite that
occupied by the apron 11, and the distance between the upper edge and the face of
the drum is adjusted by means of the swinging blade 15, by moving which the
aperture between it and the face of drum 5 can be readily altered to suit circumstances.
The adjacent end of the structure is left open, and across this opening, in vertical
direction, is arranged the movable chute 16, whose inner wall 17, is so proportioned
as to project to a higher level than the upper edge of the blade 15. By moving the
chute 16 up or down the position of the upper edge of wall 17 may be considerably
shifted. I prefer to have the upper edge of this wall curved inwardly towards
the drum 5 forming a deflector.
The opposite end of the structure is connected by a pipe 18 with an exhaust
fan of sufficient power for the purpose. It will be observed that the hopper is
closed at the bottom by means of a swinging gate 19 hinged to the hopper side,
and provided with an adjustable weight 20, so that when the load in the hopper
exceeds a
given amount, the gate 19 will automatically open and discharge the
contents in the same proportion as received into the hopper from above. By this
means the bottom of the hopper is sealed against access of air at that point and the
interior of the structure is kept substantially tight. The effect of the exhaust fan
drawing air powerfully through the air pipe 13 is to cause a strong blast of air
between the blade 15 and the drum 5, as also upwardly through the chute 16 and
the chute formed between the wall 17' and the end wall of the structure, all such
currents of air concentrating at the aperture between blade 15 and drum 5, whereby
the fine dusi, which constitutes a large and, when the ore is worked dry, a trouble-
some proportion of the gangue, is continually drawn away from the discharge
openings and expelled from the building in which the process may be carried on
along with the powerful air currents set up by the fan.
An additional and important function of the current of air thus set up and
directed is that such current after passing the blade 15 crosses the path of the falling
body of gangue which first comes away from the drum, and as such gangue is
largely composed of a light fine dust the latter is immediately diverted from its
downward path and carried by the lateral sweep of the air current along with
the fine dust already taken up by said current in the neighborhood of the
opening between blade 15 and the drum, and is swept away through the
pipe 13.
Such dust, both that in the falling gangue and that in the attracted
ore is therefore prevented from passing out at the blade 15. This important
function is attained in a simple manner by the cooperation of the fan, the chamber
below the drum, and the opening betwen blade 15 and the drum, and the process
is further simplified by the automatic action of the sealing trap at the bottom of
.the chamber.
In operating this apparatus 1 drive the drum in the direction of the arrow at
such speed as to set up a powerful centrifugal tendency. As an example, in a
case where the drum 5 will be, say, twenty-four inches in diameter I would give
it a speed approximately two hundred revolutions per minute. Under these
conditions the ore and gangue passing down the apron 11 are brought into close
proximity to the surface of the drum 5, and when the first magnetic pole is reached
a powerful magnetic attraction is set up for the particles of ore, and this magnetic
centripetal force will in all cases be made to exceed the centrifugal tendency.
As the mass moves forward with the drum 5, as soon as the lower edge of the
apron 11 has been passed, the centrifugal force, together with the force of gravity,
are free to act and the unattracted gangue together with some feebly attracted
particles having small portions of adhering iron are violently thrown off the drum
downwardly into the hopper, while the remaining particles adhere to the drum 5
as it moves to the left.
As the drum moves onwardly the adhering magnetic particles approach the
blade 15 and there meet with the powerful inward or contrary blast of air. If the

page_text: process is being operated in the dry way this air current tends to take away from
the particles of ore all adhering particles of gangue before the ore has reached its
last moment of magnetic attraction. If the process is being carried on in the wet
way this current of air towards and at the blade 15 becomes a powerful agent in
evaporating the adhering water from the remaining cleaned ore and permits its
delivery in an almost dry condition.
As the revolving drum 5 moves onwardly and the adhering particles of ore
approach a point where the magnetic attraction or centripetal force no longer
exceeds the opposing centrifugal force, the latter begins to preponderate and the
particles of ore are thereby forcibly thrown out and away from the drum 5 in a
tangential direction. The particles which contain the least iron of course
are
driven off first, and those containing the most iron adhere the longest; the result
is that by properly adjusting the chute 16 it can be arranged that a low grade of
separated ore will be projected against the deflecting wall 17 and fall down the
chute between it and the end of the structure, and the higher grade of separated ore
will all be projected beyond the deflecting wall and pass down the chute 16.
Obviously, the peculiar results thus obtained may be arrived at with different
constructions other than the one herein set forth, but I do not confine myself to any
particular apparatus or special relations of its parts, except such as are necessary to
carry our invention into practical effect, substantially as herein described.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by
my foreign correspondents I declare that what I claim is :-
First. The process of separating iron or its crushed ore from impurities, consisting
in passing the ore and gangue past a succession of two or more magnetic poles of
alternating polarity while interposing a non-magnetic screen between the ore and
the poles, and after such passage causing the separated ore to be thrown from the
magnetic field in trajectories varying with the richness of the ore, and then inter-
posing a deflector in the path of the separated ore to separate the leaner from the
richer portions.
Second. The process of separating iron or its crushed ore from impurities,
consisting in passing the ore and gangue_into and carrying the attracted portions
through a magnetic field of alternating polarity, permitting the unattracted portions
to fall from such field while causing currents of air to move first along the path of
the attracted ore in an opposite direction to the same and then to move laterally
across the path of the unattracted gangue, so as to remove from both the separated
ore and the unattracted gangue the fine dust contained therein.
Third. The process of separating iron or its crushed ore from impurities, consisting
in mingling water with the ore and gangue, passing the mass into a magnetic field
and while separating the unattracted gangue subjecting the wet ore to the evapora-
tive action of a current of air.
Fourth. The process of separating iron or its crushed ore from impurities,
consisting in mingling water with the mass, then subjecting the latter to the
simultaneous action of magnetic attraction and centrifugal repulsion while at the
same time causing a current of air to impinge upon the separated iron
or ore.
Fifth. An ore separator comprising a magnetic field, a non-magnetic screen below
and moving through said field, means for delivering the ore and gangue within the
magnetic field, and a chamber below said screen, having openings respectively near
the beginning and end of the magnetic field and means for causing a current of air
to move through said openings and across the chamber in a direction opposite that
of the screen.
Sixth. An ore separator comprising a magnetic field, a non-magnetic screen below
and moving through said field, means for delivering the ore and gangue
within the magnetic field, openings respectively near the beginning and end

page_text: of the magnetic field, means for causing a current of air to move through said
openings and across the chamber in a direction opposite that of the screen, a
discharge opening at the bottom of said chamber and a valve or gate across said
opening.
Dated this 10th day. ST……… 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.