US3849301A

US3849301A - Magnetic separator

Info

Publication number: US3849301A
Application number: US00313182A
Authority: US
Inventors: H Reading
Original assignee: Readings of Lismore Pty Ltd
Current assignee: Readings of Lismore Pty Ltd
Priority date: 1971-12-15
Filing date: 1972-12-07
Publication date: 1974-11-19
Anticipated expiration: 1991-11-19
Also published as: CA956274A; ZA728688B

Abstract

A wet magnetic separator having a rotor formed on its periphery with an annular through passage which is defined by annular walls and which is divided into channels by radially extending spacers of a magnetisable material, the rotor being surrounded by a number of pole pieces (successive ones of which being of opposite polarity) and the rotor being constructed in such manner that a magnetic field of maximum intensity is induced in the rotor spacers which are at any one time located intermediate successive pole pieces.

Description

United States Patent 1191 1111 3,849,301 Reading Nov. 19 1974 MAGNETIC SEPARATOR 901,368 10/1908 Payne 209/219 1,462,111 7/1923 Jobke 209/222 [75] lnvemor- Hugh Tmmas Readmg 2,074,085 3/1937 Frantz 209/222 x Gomeuabaht New South Wales, 3,326,374 6/1967 Jones 209/232 x Austraha 3,375,925 4/1968 Carpenter 209/223 R [73] Assignee: Readings of Lismore Pty., Limited, FOREIGN PATENTS OR APPLICATIONS New south Wales 294,321 9 1969 Australia 209/223 R Australla 401,301 11/1933 Great Britain 209/219 Dec 7 Great Britain [2]] Appl. No.: 313,182 Primary Examiner-Robert I-Ialper [30] Foreign Application Priority Data [57] ABSTRACT Dec. 15, 1971 Australia 7394 71 A wet magnetic Separator having a rotor formed its periphery with an annular through passage which is 52 us. 01 209/214, 209/221, 209/232 defined by annular Walls and which is divided into 51 Int. (:1. B030 1/00, B030 1/10 channels by radially extending spacers of a magnetisa- 5 w f Search H 2 9 2 9 22 2 2 ble material, the rotor being surrounded by a number 209 220 227 232 22 2 4; 2 0 2 2 223 of pole pieces (successive ones of which being of 0pposite polarity) and the rotor being constructed in 5 References Cited such manner that a magnetic field of maximum inten- UNITED STATES PATENTS sity is induced in the rotor spacers which are at any one time located intermediate successive pole pieces. 345,383 7/1886 Kesslen 209/219 X 823,492 6/1906 Dunham 209/219 10 Claims, 2 Drawlng F g s PATENTE SUV 1 9 I974 sum 2 or 2 1 MAGNETIC SEPARATOR This invention relates to a separator for employment in magnetic separation of magnetic particles from a fluid suspension, and in particular to a separator of the type having a rotor surrounded by a number of fixed magnetic poles, successive ones of which are of opposite polarity.

'The separator in accordance with the present invention (as hereinafter defined) may be considered in the context of the somewhat similar separator subject of Australian Pat. No. 294,321. The separator subject of that Patent incorporates a rotor, the periphery of which is formed with a series of surface channels or grooves, and it is surrounded by a number of magnetic poles, the successive ones of which are of opposite polarity. The arrangement of the poles, with respect to the rotor, is such that an area of maximum magnetic concentration occurs at the surface of the rotor which at any one time is adjacent a pole and an area of minimum magnetic field strength occurs at the rotor area which, at any one time, is located intermediate successive poles. This arrangement permits collection from below the rotor of non-magnetic particles in approximate alignment with the point of feed to the rotor and collection of magnetic particles by washing at a point intermediate successive poles.

The separator subject of the above-referenced Patent, and as above described in brief, has been found ideally suited for the separation of a composite material from which non-magnetic particles are to be collected as the component of interest. However, it has been found that the separator described in the above Patent does not have, under certain conditions, sufficient capacity for the separation of a composite from which magnetic particles are to be collected and from which non-magnetics are to be discharged as unwanted or waste components, particularly where the magnetic particles do themselves constitute the largest proportion of the total composite. The present invention seeks to provide a separator which may be employed efficiently for this purpose.

Thus, there is provided in accordance with the present invention a separator for employment in the magnetic separation of magnetic particles from a fluid suspension, and which comprises:

a. a rotor having at least one annular through passage constituting or formed on its periphery, the through passage being disposed about the axis of rotation of the rotor;

b. a number of spacers of a magnetically permeable material extending between walls of the or each passage, successive spacers, together with the passage walls, defining through channels into which magnetic particles in a fluid suspension may be fed to pass in a direction substantially parallel to the axis of the rotor;

c. a number of magnetic pole pieces surrounding the rotor and having their magnetic axes disposed radially with respect to the rotor, successive ones of the pole pieces being of opposite polarity and the relationship of the pole pieces to the rotor being such that a magnetic field of maximum intensity is induced in the rotor spacers which are at any one time located intermediate successive ones of the pole pieces;

d. means for feeding a compositecontaining magnetic particles in a fluid suspension into said channels adjacent successive ones of the pole pieces;

e. means also adjacent successive ones of the pole pieces for washing magnetic particles from within the channels;

f. means intermediate successive pole pieces for delivering washing water to successive channels; and

g. separate means for collection of magnetic and nonmagnetic particles which are passed or. washed through the channels.

Preferably, the spacers are formed on opposite side faces thereof, with corrugations and, also as a preferable feature, the successive spacers, in extending between upper and lower ends of the rotor, incline (as a helix) in the direction of rotation of the rotor.

The walls of the through passage or passages referred to above are preferably formed from bands of stainless steel having essentially non magnetic characterisitics, and the spacers above stated would be formed from a high permeability stainless steel. An inner one of the through passage walls is interconnected with the rotor hub by a number of radially extending spokes, which are also, preferably, formed of a non-magnetic stainless steel.

The rotor is preferably cylindrical in form but it might be tapered as a truncated cone between the upper and lower ends thereof. ln such a case the material passed through the channels defined by the spacers and the rotor walls would not (or need not) travel in a direction which is strictly parallel to the rotor axis, and the above statement that the fluid is fed to pass in a direction substantially parallel with the axis of the rotor is to be read in this context.

The invention will be more fully understood from the following description of a preferred embodiment thereof taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is an elevation view of a magnetic separator with a portion thereof shown in section, and

FIG. 2 is a perspective view of a rotor assembly of the separator, the relationship of the rotor assembly to a number of associated pole pieces being also illustrated.

As shown, the separator comprises a rotor l0 which is keyed to a rotor shaft 11. The shaft 11 is journalled for rotation in bearings 12 and 12a which are, in turn,

- carried by support arms 13 and 13a of a support frame 14. Drive is transmitted to the rotor shaft from a motorgearbox arrangement 15 via a coupling 16.

The rotor 10 comprises a hub 17, a number of nonmagnetic stainless-steel spokes l8 and, constituting the periphery of the rotor, two non-magnetic stainless-

steel bands

19 and 20. The

bands

19 and 20 are spaced-apart in a radial direction to define an intermediate through passage 21 which extends around the periphery of the A splash guard 22 is located above the rotor.

A series of corrugated form spacers of a magnetically permeable material 23 extend in a radial direction between the two

passage forming walls

19 and 20, successive ones of the spacers, together with the passage walls defining through-channels for a material slurry or composite fed thereto.

The spacers 23 extend for approximately the height of the rotor, and they are inclined slightly in the direction of rotation of the rotor so as to provide a simulated helical path for material conveyed through the channels of the rotor.

A number of electrically energised magnetic pole pieces 24 which are yoked by a mild-steel band 25 surround the rotor (although only two such pole pieces are shown in FIG. 2) and successive ones of the pole pieces are energised so as to be of opposite polarity. With this construction a maximum flux density or field strength will occur in the spacers 23 which are at any one time positioned intermediate successive pole pieces, and a minimum flux density will occur in the same spacers when they are positioned in direct alignment with the axes of the successive pole pieces.

With the apparatus described thus far, a slurry form composite material from which magnetic particles are to be separated is conveyed from a storage receiver 26 into the rotor channels at successive points around the periphery of the rotor adjacent the trailing edge of each of the pole pieces in the direction of feed of the rotor. The composite material is delivered by way of fixed delivery nozzles 27. In feeding the composite material at this point, magnetic and partially magnetic particles will be held captive upon the surface of the spacers 23, and non-magnetic particles will flow straight through the channels, to be collected in a non-magnetics launder 28 located beneath the rotor.

A wash water is supplied to the channels via delivery lines 29 and nozzles 30 at a point intermediate successive pole pieces for washing magnetic particles (or middlings) of low concentration into launders 31. The product which flows into the launders 31 may be either treated as waste or be recycled through the machine.

Then, at a point in alignment with the magnetic axes of the successive pole pieces, a further wash water supply is delivered to the channels via delivery lines 32 and nozzles 33 in order to wash magnetic particles into launders 34.

I claim:

1. A magnetic separator-comprising:

a. a magnetically impermeable rotor mounted on a vertically oriented shaft and having at least one annular through passage constituting or formed on its periphery and defined by spaced-apart walls, the walls being formed from a material having nonmagnetic characteristics, and the or each through passage being disposed about the axis of rotation of the rotor,

b. a number of spacers of a magnetically permeable material extending in a radial direction between the walls of the or each passage, successive spacers, together with the passage walls, defining through channels into which magnetic particles in a fluid suspension may be fed to pass in a direction substantially parallel to the axis of the rotor,

c. a number of magneticpole pieces surrounding the rotor and having their magnetic axes disposed radially with respect to the rotor, successive ones of the pole pieces being of opposite polarity whereby a magnetic field of maximum intensity is induced in the rotor spacers intermediate successive ones of the pole pieces;

d. means for feeding a composite containing magnetic particles in a fluid suspension into said channels adjacent successive ones of the pole pieces;

e. means also adjacent successive ones of the pole pieces for delivering a washing fluid for washing magnetic particles from within the channels;

f. means intermediate successive pole pieces for delivering a washing fluid to successive said channels, for washing non-magnetic particles from within the channels, and

g. separate means for collection of magnetic and nonmagnetic particles which are passed or washing through the channels.

2. A magnetic separator as claimed in claim 1 wherein the rotor is formed on its periphery with a single said through passage and wherein the spacers extend radially between the walls thereof.

3. A magnetic separator as claimed in claim 2 wherein the spacers are formed on their opposite (channel defining) faces with corrugations which extend in a direction between opposite ends of the rotor.

4. A magnetic separator as claimed in claim 2 wherein the spacers have a length approximately equal to the axial length of the rotor and the spacers are inclined in the direction of rotation of the rotor.

5. A magnetic separator as claimed in claim 2 wherein the through passage is concentric and parallel with the axis of the rotor.

6. A magnetic separator as claimed in claim 2 wherein the passage defining walls of the rotor are constituted by annular bands of a stainless steel having non-magnetic characteristics.

7. A magnetic separator as claimed in claim 2 wherein the means for feeding the composite into' the rotor channels are located outside one end of the rotor and adjacent the trailing edge of the respective pole pieces in the direction of rotation of the rotor.

8. A magnetic separator as claimed in claim 2 wherein the means for delivering a washing fluid for washing magnetic particles from within the channels are located outside one end of the rotor and are aligned with the axis of the respective pole pieces.

9. A process for effecting separation of magnetic particles from a composite fluid suspension material comprising the steps of: passing the composite material having magnetic and nonmagnetic ingredients therein through an annular passage of a rotor rotating about a vertical axis having magnetically impermeable spacedapart walls defining such annular passage, collecting the magnetic particles on the surfaces of a number of spaced magnetically permeable spacers which are disposed at regular circumferential intervals within said passage to define channels receiving a flow of such fluid suspension as it is directed substantially parallel to the axis of the rotor, imposing a magnetic force through a series of circumferentially spaced magnetic pole pieces surrounding said rotor to develop a magnetic field of maximum intensity in the rotor spacers intermediate successive ones of pole pieces, washing in the region of said successive pole pieces the magnetic particles from within the channels and which are adhered to said spacers, and separately washing in the region intermediate said successive pole pieces and collecting a the non-magnetic particles from within said channel.

10. The process in accordance with claim 9 includingthe step of separately collectingthe magnetic and nonmagnetic particles which are washed through the channels.

Claims

1. A magnetic separator-comprising: a. a magnetically impermeable rotor mounted on a vertically oriented shaft and having at least one annular through passage constituting or formed on its periphery and defined by spacedapart walls, the walls being formed from a material having nonmagnetic characteristics, and the or each through passage being disposed about the axis of rotation of the rotor, b. a number of spacers of a magnetically permeable material extending in a radial direction between the walls of the or each passage, successive spacers, together with the passage walls, defining through channels into which magnetic particles in a fluid suspension may be fed to pass in a direction substantially parallel to the axis of the rotor, c. a number of magnetic pole pieces surrounding the rotor and having their magnetic axes disposed radially with respect to the rotor, successive ones of the pole pieces being of opposite polarity whereby a magnetic field of maximum intensity is induced in the rotor spacers intermediate successive ones of the pole pieces; d. means for feeding a composite containing magnetic particles in a fluid suspension into said channels adjacent successive ones of the pole pieces; e. means also adjacent successive ones of the pole pieces for delivering a washing fluid for washing magnetic particles from within the channels; f. means intermediate successive pole pieces for delivering a washing fluid to successive said channels, for washing nonmagnetic particles from within the channels, and g. separate means for collection of magnetic and non-magnetic particles which are passed or washing through the channels.

7. A magnetic separator as claimed in claim 2 wherein the means for feeding the composite into the rotor channels are located outside one end of the rotor and adjacent the trailing edge of the respective pole pieces in the direction of rotation of the rotor.

9. A process for effecting separation of magnetic particles from a composite fluid suspension material comprising the steps of: passing the composite material having magnetic and nonmagnetic ingredients therein through an annular passage of a rotor rotating about a vertical axis having magnetically impermeable spaced-apart walls defining such annular passage, collecting the magnetic particles on the surfaces of a number of spaced magnetically permeable spacers which are disposed at regular circumferential intervals within said passage to define channels receiving a flow of such fluid suspension as it is directed substantially parallel to the axis of the rotor, imposing a magnetic force through a series of circumferentially spaced magnetic pole pieces surrounding said rotor to develop a magnetic field of maximum intensity in the rotor spacers intermediate successive ones of pole pieces, washing in the region of said successive pole pieces the magnetic particles from within the channels and which are adhered to said spacers, and separately washing in the region intermediate said successive pole pieces and collecting the non-magnetic particles from within said channel.

10. The process in accordance with claim 9 including the step of separately collecting the magnetic and nonmagnetic particles which are washed through the channels.