Improvements in Magnetic Separators.
Year: 1899

page_text: Date of Application, 3rd Oct., 1899
Complete Specification Left, 3rd July, 1900-Accepted, 4th Aug., 1900
PROVISIONAL SPECIFICATION.
Improvements in Magnetic Separators.
I, WILLIAM 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 communication to me
by Charles Frederick Courtney, of Broken Hill, in the Colony of New South
Wales), to be as follows:
--
This invention relates to improvements in the magnetic separation of mineral
earths and mixtures, especially sulphide ores and tailings, by passing the same
through a concentrated magnetic field, the invention being applicable to the
treatment of dry or wet, but especially wet, materials.
According to this invention the ore is not subjected to the action of gravity
contrary to magnetic attraction until the moment of subjection to the magnetic
action whereupon gravitation is taken advantage of to the fullest extent.
The machine consists of a double series of pole pieces alternately arranged
along a non-magnetic cylinder rotating with a horizontal spindle, the cores
themselves constituting the revolving spindle. The tapered pole pieces, of soft
iron, are arranged in two sets, the north poles being connected to the core at
one end of the cylinder and the south poles to the core at the other end, the
magnetic cores being attached to the cylinder by set screws. The pole pieces are
set at equal distances from each other with their surfaces projecting slightly
beyond that of the cylinder, their edges being parallel with each other. The
whole is encased in a wooden box. The cores pass through non-magnetic glands,
the bobbins being suspended upon brackets on the outside of the box and sur-
round the spindles. Above the cylinder is a hopper with a bottom roller supply-
ing a thin film of material to the revolving cylinder. Beneath the cylinder
inside the wooden box, are receivers which catch differential magnetic particles,
adjustable brushes being employed against revolving cylinders to remove the
magnetic particles therefrom. Alternatively the cylinders may be inclined or
vertical and conical with other parts to correspond.
Dated this 3rd day of October 1800
Improvements in Magnetic Separators.
I, WILLIAM CLARK, of the Firm of A. M. & Wm. Clark, of 53, Chancery
35 Lane, in the County of Middlesex, Fellow of the Chartered Institute of Patent
DQ77

page_text: Agents do hereby declare the nature of this invention (a communication to me
by Charles Frederick Courtney, of Broken Hill, in the Colony of New South
Wales), and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
is
This invention relates to the magnetic separation of paramagnetic substances,
particularly those of low magnetic permeability, from ores and mixtures with
which they are associated, by passing said ores or mixtures in a comminuted
state through a condensed or concentrated magnetic field. The invention
more especially designed for the treatment of Broken Hill sulphide ores and
tailings and is particularly adapted for treating materials in the wet state, the
object being to effect the separation in the most economical manner and without
employing expensive or delicate apparatus and especially without using belts or
bands for feeding the material to the machine; the objection to the employment
of belts or bands being, as is well known, that these appliances, besides requir-
ing frequent renewal, do not readily lend themselves to operation with a wet
process.
According to this invention the comminuted ore or other mixture is subjected
in the form of a thin film to a highly concentrated magnetic field so as to
avoid risk of the paramagnetic particles becoming prematurely detached from
the magnetic poles and swept away by the passing stream of matter of lower
magnetic permeability with which they are associated. Further, the material
under treatment is prevented from falling freely under the influence of gravity at
the moment when the material enters the magnetic field; so that the paramagnetic
particles contained in the mixture however low their magnetic permeability, are
not liable to become lost in consequence of their passing over or escaping fron
the magnetic poles under the influence of momentum acquired previous to their
entrance into the magnetic field. From the moment of such entrance however,
and so long as the material remains within the magnetic field those particles
which are paramagnetic or possess a higher degree of magnetic permeability are
retained by magnetic attraction whilst those particles which are diamagnetic
or possess a lower degree of magnetic permeability become free to yield to the
attraction of gravity and to fall out of the magnetic field whereby a practically
thorough separation is effected between these constituents of the ore
mixture.
or other
The apparatus of our invention comprises an electro-magnet having multiple
pole pieces of positive and negative polarity alternately around the periphery of
a supporting drum of non-magnetic material, the drum being mounted to revolve
within a casing or water tank and carried by gudgeons which also constitute the
electro-magnetic cores, the pole pieces of one sign being in magnetic connection
with the core at one end of the drum, and the pole pieces of the contrary sign
being connected to the core at the opposite end of the drum so that they pre-
sent a succession of magnetic fields in the direction of the circumference of the
drum. The apparatus further comprises means of feeding the material on to the
upper part of the drum; a brush for removing such portion of the material as
adheres to the drum; and bins for receiving the separated components of the
mixture. The apparatus so constituted may be combined together in pairs as
hereafter described, each pair being contained within a single casing so as to
form a double machine.
In the accompanying drawings forming part of this specification, Figure 1 is
a longitudinal sectional elevation, and Figure 2 is a cross sectional elevation of
a double machine, the one drum and its appurtenances being shewn in elevation
and the other in section in the latter figure. Figure 3 is a plan of the same
partly in section, Figure 4 is a cross section of two adjacent pole pieces, drawn
to a larger scale, and Figure 5 is a detail of a modification, with parts in section.
A is a tank wherein are mounted to revolve two horizontal drums B B*; the
two drums being similar in construction, only one of them will be described.
Each drum comprises oppositely magnetized heads C D of soft iron and an inter-

page_text: mediate peripheral portion or body B₁ of non-magnetizable material such as gun-
metal fixed to the heads by screws F and forming a support for multiple pole
pieces CD. The pole pieces C¹ D¹ are of soft iron and are fixed to the peri-
phery of the heads CD and to the support B₁ by screws E, the pole pieces C¹
being connected to the head C and the pole pieces D¹ to the head D, the pole pieces
of the two sets extending longitudinally of the drum from opposite ends, and
those of the one set or polarity alternating with those of the other set or polarity
around the periphery of the drum. The supporting peripheral portion B¹ of the
drum is grooved to receive the pole pieces which are embedded in the grooves for
the greater part of their depth so that the pole pieces are firmly supported in posi-
tion and the intervening gaps are closed by the non-magnetic material B.
c d
The pole pieces C¹ D' are not embedded in the non-magnetic material B₁ for
their whole thickness but project slightly as shewn in Figure 4 so as to form
between adjacent pole pieces a shallow groove in which the particles of material
lie whilst within the magnetic field and leave exposed the salient acute edges
of the pole pieces where the strength of the magnetic field is greatest. With
the object of concentrating the magnetic force at their edges cd the pole pieces
are tapered towards their salient edges, the sides being bevelled so as to make
these edges acute.
In order to equalize the intensity of the magnetic field longitudinally of the
drum. the pole pieces are also tapered in the direction of their length, botli as
regards their width as shewn in Figure 1, and as regards their thickness as shown
in Figure 2, the narrower and thinner free end of each pole piece lying between
the broader and thicker fixed ends of the adjacent pole pieces, so that the gap
intervening between cach pair of adjacent pole pieces is of equal width through-
out its entire length.
The heads CD of the drum B are formed in one with gudgeons CD2 which
revolve in stuffing box bearings () in the sides of the tank A and are of suffi-
cient length to pass through and form the cores of electro-magnets CD of which
the coils are stationary, whilst the gudgeons C2 D³, which also form the cores
The outer ends of the
of the electro-magnets. rotate freely within them.
cores C2 D2 are journalled in bearings g and the electro-magnet coils C³ D³ are
supported on brackets H.
The two drums B and B and their electro-magnetic appurtenances are similar
in construction, and the gudgeon or core D2 at the one end of drum B is mag-
netically connected to the core C2 at the same end of drum B*, by a yoke bar G
of soft iron in which are formed the bearings g wherein the outer ends of the said
two cores D2 C³ rotate, and by which they are magnetically connected, whilst
the corresponding coils D3 C3 are similarly wound and have their windings con-
nected so that the core D2 and coil 13 at the one end of the drum B and the
core C2 and coil 03 at the same end of the other drum B* form the oppositely
polarized limbs of the same horse-shoe electro-magnet. The arrangement is the
same at the other side of the machine, the polarity being of course reversed rela-
tively to the drums so that the two cores C2 D2 of each drum will be of opposite
polarities.
The two cores C2 D2 at the one side of the machine are geared together by
spur wheels J of non-magnetic material so that the drums B B* will be rotated in
opposite directions, when driven through pulley N fast on one of the cores at the
other side of the machine.
P is a feed hopper whence the material is delivered on to the drum B through
the medium of a distributing roller Q and chute S, the roller Q being driven by
geared wheels R from one of the gudgeons of the drum. The latter is provided
with flaring flanges M whereby the material is confined within the active por-
tion of the peripheral surface of the drum, that is to say within the concen-
trated magnetic field.
T is a brush of non-magnetic material for removing from the drum such par-
ticles of the material under treatment as adhere to the drum by magnetic attrac-

page_text: A
tion, the brush extending between the flanges M M and being so placed that any
point on the periphery of the drum, after passing beneath the chute S, will per-
form about three-fourths of a revolution before encountering the brush.
bin X is placed beneath the drum B at the same side as the brush T so as to
receive the particles removed thereby from the drum, whilst another bin Y is
placed contiguous to X in order to receive those particles which fall from the
drum by gravitation alone. The brush T is mounted in guides so as to be adjust-
able for wear.
The machine is adapted for treating the material either dry or in water. We
prefer to treat the material in water, and the apparatus illustrated in the draw-
ings, is specially designed for the wet system of treatment. To this end the
casing A is made watertight and is filled with water to such a level as to cover
the drums and pole pieces, the stuffing boxes 0 affording freedom of rotation to
the gudgeons C2 D whilst preventing the escape of water. The bearings of the
spindle which carries the feed roller Q are likewise provided with stuffing boxes.
In operation, the electro-magnet coils CD3 are supplied with current of a
strength proportioned to the degree of concentration required in the product, and
the drum B being rotated at a suitable speed, the pulverized ore or other mix-
ture is fed into the hopper P, whence it is received by the roller Q which dis-
tributes it evenly upon the inclined chute S whereby the material is gently
delivered in a thin uniform film upon the upper part of the drum. By the revo-
lution of the drum in the direction indicated by the arrow b, the particles com-
posing the film of material are at once subjected to the influence of gravity acting
in opposition to that of the magnetic attraction, and are eventually carried round
to a point where those particles which are non-magnetic, or possess a lower degree
of magnetic permeability, fall off the drum by their own weight and are received
in the bin whose edge is situated a little beyond the lowest point reached by
the periphery of the drum in its rotation so as to ensure that no such particles
as fall from the drum by gravitation alone shall find their way into the bin
reserved for the more magnetic particles. Those particles which adhere to the
drum by magnetic attraction are carried (by the continued rotation of the drum)-
beyond the range of the bin Y and thence upward until they are arrested and
removed from the drum by the brush T which deposits them in the bin X.
If it be desired to effect further concentration by a repetition of the above
described process, the contents of either or of both bins may be conveyed to a
second apparatus in order to again undergo similar treatment.
The herein described apparatus, besides being adapted to the separation of para-
magnetic from diamagnetic substances, may also be used for the separation of
paramagnetic substances possessing different degrees of magnetic permeability,
by suitably regulating the speed of rotation of the drum B and the strength of
the electric current whereby the magnets are excited.
The pole pieces D C may be projected from rings DC so forming crowns as
represented in Figure 5 and which will be shrunk on to the cores.
Reverting to the pole pieces C₁ D₁ we would have it understood that they may
be run in with white metal or other non-magnetic material in lieu of recessing.
them as shown in Figure 4, and also that a lesser number of such pieces may be
employed than is shown on Figures 1 and 2.
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. A magnetic separator for the treatment of comminuted ores and other mix-
tures comprising an electro-magnet having a multiple series of positive and nega-
tive pole pieces attached in alternate order around the periphery of a non-
magnetic rotary drum mounted upon a pair of gudgeons which themselves con-
stitute the cores of the electro'magnet; exciting coils about the cores, and meaus
of feeding the material to the drum, substantially as described.

page_text: 2. A magnetic separator for the treatment of comminuted ores or other mix-
tures in the wet state, comprising an electro-magnet having rotary cores in axial
alignment with one another; multiple positive and negative pole pieces connected
to the respective cores and attached in alternate order around the periphery of
a rotary non-magnetic drum whose gudgeons are respectively formed by the
rotary cores of the electro-magnet; a casing for the apparatus adapted to con-
tain water sufficient to cover the drum and pole pieces; exciting coils for the
magnet cores, wound on bobbins situated externally of the casing, said bobbins
being stationary whilst the cores rotate within them, substantially as specified.
3. In a rotary magnetic separator for the treatment of comminuted ores and
other mixtures, the combination with a non-magnetic drum supported upon and
rotated by a pair of gudgeons constituting the cores of an electro-magnet, of a
series of metal bars or plates forming the positive and negative pole pieces of said
electro-magnet, attached to the periphery of the drum in alternate order and
connected to oppositely magnetized cores said pole pieces tapering both as regards
width and thickness in the direction of their length and as regards thickness in
the direction of their width so as to have acute salient edges, the opposed edges
of adjacent pole pieces being parallel, so as to produce an intense magnetic field
having uniform intensity longitudinally of the drum and adapted to continuously
receive and act upon a stream of material supplied to it, substantially as specified.
4. A magnetic separator consisting essentially of a revolving drum formed of
alternating pole pieces fixed to the oppositely magnetized heads of the drum, the
pole pieces being tapered in form both as regards thickness and width, as
described so as to have acute salient edges and produce between those edges a con-
centrated magnetic field of substantially equal intensity throughout the whole
length of the pole pieces, the pole pieces being partially embedded in grooves in
a peripheral support or body portion made of non-magnetizable material which
closes and partially fills the gaps between the pole pieces, leaving the acute edges
of the pole pieces salient and forming grooves between then substantially as
specified.
5. In a magnetic separator for the continuous treatment of comminuted ores
or other mixtures, the combination with a pair of axially aligned rotary shafts
adapted to form both the gudgeons of a rotary non-magnetic drum and the cores
of an electro-magnet whose multiple positive and negative pole pieces are attached
in alternate order around the periphery of said drum, of stationary exciting coils
wound upon bobbins through which said rotary cores pass and of a stationary
yoke magnetically connecting the outer ends of the cores, substantially as
specified.
6. In a magnetic separator for the treatment of comminuted ores and other
mixtures, the combination with a rotary cylinder or drum around the periphery
of which are presented a multiple series of magnetic pole pieces, and with a feed
hopper for the material to be treated, surmounting the drum and provided with
an outlet in the form of a narrow slit, of a distributing roller and delivery chute
interposed between the outlet of said hopper and the drum and in immediate
proximity to the latter so as to gently deliver the material in a thin uniform
continuous film upon the upper part of the cylinder or drum, substantially as and
for the purpose specified:
7. In a magnetic separator for the treatment of comminuted ores and other
mixtures, the combination with a rotary cylinder or drum around the periphery
of which are presented a multiple series of magnetic pole pieces whereby is pro-
duced a magnetic field adapted to continuously receive and act upon a stream of
material supplied to it, of a non-magnetic brush or scraper contacting with the
drum for the purpose of detaching the particles of material adhering to the pole
pieces, and independent bins placed beneath the drum and adapted to receive the
separated constituents of the material treated, substantially as specified.
8. In a magnetic separator for the continuous treatment of comminuted ores
and other mixtures in the wet state, the combination with an electro-magnet

page_text: having rotary cores in axial alignment with one another and multiple positive and
negative pole pieces connected to the respective cores and attached around the
periphery of a horizontal rotary non-magnetic drum whose gudgeons are respec-
tively formed by the rotary cores of the electro-magnet, and with a casing for
the drum, adapted to contain water sufficient to cover the drum and pole pieces,
or stuffing boxes adapted to give passage to and form bearings for said rotary
cores, and of stationary exciting coils wound upon bobbins supported externally
of the casing and adapted to permit of the cores revolving freely within them,
substantially as specified.
9. A duplex magnetic separator comprising two rotary drums each having lon-
gitudinally extending peripheral pole pieces fixed in alternate order to magnetiz-
able heads in one with the gudgeons of the drum, which gudgeons also form rotary
cores of stationary electro-magnetic coils, the windings of the coils at the corre
sponding ends of the two drums being connected, and their cores being magneti-
cally coupled by a yoke bar in which the cores rotate, so that the coils and cores
at the same side of the machine constitute the two limbs of a single electro-
magnet, the construction being similar at the other side of the machine, but with
the relative polarity reversed so that the two heads of each drum will be of oppo-
site polarities.
Dated this 2nd day of July 1900
A. M. & WM. CLARK,
. Chartered Patent Agents, 53, Chancery Lane, London.