US2868377A - Magnetic separator - Google Patents

Description

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MAGNETIC SEFARATOR Filed April 10, 1956 2 Sheets-Sheet 2 //VVENTOR 390a 7e Zis SWZ'PSKZZS wmgm m ATTOR NE YS United States Patent *MAGNETIC SEPARATOR Becalelis Svirskis, Auckland, Auckland, New Zealand Application April 10, 1956, Serial No. 577,414

Qlaims priority, application Australia April 12, 1955 4 Claims. (Cl. 209219) This invention relates to magnetic separators and refers particularly to separators which separate magnetic components from the non-magnetic or lessmagnetic components of slurries or similar wet mixtures of sized materials. For convenience of description, a magnetic separator of this type will be hereinafter referred to as a wet magnetic separator.

According to this invention a wet magnetic separator comprises a rotor which is adapted to rotate between magnetic poles so that lines of magnetic force will pass between the poles through said rotor, a table on to which a slurry of the material to be treated is fed, a section of the table passing between the rotor and one of said poles in such manner that the components of the slurry in passing along said section will be. separated magnetically into two groups, and means for separating the components of one group from the components of the other group. Preferably the parts and-the magnetic field are arranged so that the magnetic components, or the greater proportion thereof, adhere to the rotor and are thus carried beyond the table while the non-magnetic or less magnetic components of the slurry remain on the table. For efficient separation of the components, the table and the surface of the poles facing the rotor are curved concentrically with the surface of the rotor and, in the vicinity of the rotor, the distance between the table and the rotor is less than the distance between the table and the adjacent pole. Means may also be provided for adjusting the distance between the table and the adjacent pole and between the. table and the rotor.

To afford a better understanding of the practice of the invention, reference will now be made to the accompanying drawings which illustrate a typical embodiment of the invention. In the drawings:

Figure 1 is a view of the separator in sectional side elevation,

Figure 2 is a plan view of the separator shown in Figure 1,

Figure 3 is a fragmentary view on an enlarged scale showing one type of rotor contour which may be made use of in the machine, and

Figures 4 to 8 are further fragmentary views showing other types of rotor contours.

Figure 9 is aview of the means for removingmagnetic components from the surface of the pick-off roller in sectional side elevation.

As shown in the drawings, a wet magnetic separator in accordance with the invention, comprises a mild steel U-shaped electro-rnagnet in the form of an upright member 1 at one end and upper and lower horizontal members 2, '3 respectively, which extend outwardly in the same direction from the upper and lower ends of the upright. An upper magnetic pole 4 is adjustably mounted on the lower side of the outer end of the upper horizontal member 2 and a lower magnetic pole 5 is adjustably mounted on the upper side of the outer end of the lower horizontal member 3, the lower pole 5 being slightly closer to the upright 1 than the upper pole 4.

A coil 6 of copper or other suitable conducting wire is wound around the upright member 1 in such manner as to excite the magnet when current is passed through the coil.

A cylindrical rotor 7 is mounted for rotation about a transverse axis between the upper and lower members of the electro-magnet. The surfaces of the magnetic poles 4, 5, are spaced a short distance from the curved surface of the rotor and are curved in conformity therewith. The rotor is made from thin silicon steel discs mounted on a shaft 8 between cheek plates 9 which are secured on the shaft by means of threaded collars 10 which are screwed up against the cheek plates. The discs which together comprise the rotor are of different .diameters and are arranged on the shaft so as to provide the desired contour for the rotor. Examples of various rotor contours are shown in Figures 3 to 8, the actual contour used in any case depending upon the nature and actual size of the materials which are to be treated in the separator.

. A feed hopper 11 for the material to be treated is located above the upper horizontal member 2 and is provided with a perforated screen 12 to prevent oversize particles from entering the separator. The hopper 11 is provided with a series of downwardly extending feed pipes 13 which pass through the upper horizontal member 2 so that material from the hopper can be fed on to the sloping portion of a table 14 disposed below the lower ends of the feed pipes 13. A horizontal water spray pipe 15 is located in the feed hopper 11 and is used to control the water content of the slurry which is fed through the feed pipes on to the table. A rotary agitator 16 may also be provided in the hopper if desired. The table 14 slopes downwardly towards the lower magnetic pole 5 andpasses between the latter and the adjacent curved surface of the rotor 7, the clearance between the rotor and the table being less than the clearance between the table and the curved surface of the lower pole. A second spray pipe 17 is located above the sloping section of the table to further dilute and disperse the slurry as it moves down the sloping surface of the table towards the rotor. Beyond the lower magnetic pole 5, the table leads on to the upper end of a steeply sloping launder 18 down which material reaching the lower end of the table will pass.

A strongly magnetized pick-off roller 19 fabricated from mild steel or silicon steel is disposed so that its surface is adjacent to the surface of the rotor at a 1 position between the upper and lower magnetic poles 4, 5.

The pick-off roller 19 is arranged in frictional engagement with the cheek plates 9 at the ends of the rotor 7 so that it is rotated in unison with the rotor 7 and in the opposite direction thereto. As the rotor is arranged to be driven anti-clockwise as seen in Figure l, the pick-off roller 19 will rotate clockwise at the same speed- A scraper 2011, as shown in Fig. 9, of rubber or felt is arranged in relation tothe pick-off roller 19 so that material on the surface of the latter will be removed as the roller rotates and will pass on to the upper end of a second launder 20 which slopes downwardly in a direction substantially parallel to the first launder 18. A transverse water. spray pipe 21 arranged above the pickoff roller 19 is adapted to direct a curtain of water against the rising surface of the rotor 7 so that any material adhering to the rotor in the vicinity of the spray pipe will be washed downwardly on the rotor towards the first launder 18 for a purpose referred to hereinafter.

In operation, the material to be treated is fed into the hopper 11 where particles not greater in size than the smallest clearance between the table 14 and the rotor 7 will pass through the screen 12 and will be brought into Patented Jan. 13, 1959 the form of a slurry by means of water from the spray is rotated above the slurry in the same direction as the flow of the slurryalong the table. On the other hand the non-magnetic components of the slurry will not be affected and will remain on the table. When the slurry reaches the end of the table 14, the non-magnetic components will flow downwardly over the surface of the first launder 18 whereas the magnetic components will continue to adhere to the ridges of the rotor until they have been raised thereon to a position opposite the pickoff roller 1a. At this point the magnetic components are, due to the greater magnetic attraction of the pick-off roller, caused to leave the rotor and adhere tothe surface of the roller which, as explained above, is being rotated in a clockwise direction by its frictional engagement with the cheek plates 9 at the ends of the rotor.

The scraper in engagement with the surface of the pick-off roller operates to remove the magnetic components from the surface of the pick-off roller and these components then pass downwardly along the sloping surface of the second launder 20 being thereby separated from the non-magnetic components which pass downwardly along the first launder 18. If any non-magnetic components are swept upwardly by the rotor past the first launder 18, such components will normally be disposed in the valleys of the rotor and will not leave the surface of the rotor as the latter passes the pick-off roller. The action of the spray pipe 21 is such as to cause any non-magnetic components still adhering to the rotor to be washed downwardly along the valleys on the rotor without interfering with the magnetic components which are disposed on the ridges of the rotor. The non-magnetic components thus washed downwardly over the rotor will be carried on to the surface of the first launder 18 along with the non-magnetic components which fall directly on to the first launder over the edge of the table 14. It is thus apparent that an eflicient means for separating the magnetic and non-magnetic components of the slurry is provided by separators in accordance withthe invention.

In operation, the speed of the rotor is adjusted according to the density and particle size of the slurry being treated. The poles are removable from the upper and lower members and poles of different designs may be used as may be deemed expedient. The separator can, of course, be made of any width and any size having either one or more rotors depending on the size of the electro-magnet. For example, an H-shaped electro-magnet may be used in which the coil is wound round the central vertical member and a rotor is located at each end between upper and lower horizontal members on each side of the central vertical member. If necessary, the polarity of the electro-magnet could be reversed for any materials which are weakly magnetic and tend to retain magnetism. v 7

Wet separators in accordance with the invention are particularly suitable for the treatment of beach sands in order to extract economically valuable minerals such as rutile and ilmenite therefrom.

1. A wet magnetic separator comprising in combination a magnet having upper and lower poles, a rotor disposed between the poles of the magnet so that lines of magnetic'force will pass between the poles through said 4 rotor, the surface of said rotor being in the form of alternate ridges and valleys arranged circumferentially, means for rotating said rotor, a table onto which a slurry of the material to be treated is fed, a section. of the table passing between the rotor and the lower pole in such manner that the components of the slurry in passing along said section will be separated magnetically into two groups, the said section of the table being closer to the surface of the rotor than to the surface of the lower pole, means to adjust the water content of the slurry fed onto the table, a first launder to collect the non-magnetic components of the slurry which pass over the end of said table, a strongly magnetized pick-off roller disposed beyond the end of said table and having a'surface in close proximity to the surface of the rotor whereby the magnetic components of said slurry adhering to the rotor pass beyond the end of said table are magnetically attracted to the surface of said pick-off roller, means to rotate the pick-off roller in the opposite sense to said rotor, means adapted to remove 'the said magnetic components from the surface of the pick-off roller, a second launder to receive the magnetic components removed from the pick-off roller, and a water spray directed onto the surface of the rotor above the pick-off roller whereby any non-magnetic components still adhering to the valleys of the rotor will be washed downwardly along the valleys of the rotor onto the said first launder without interfering with the magnetic components which are disposed on the ridges of the rotor.

2. A wet magnetic separator as claimed in claim 1, in which the said rotor comprises a shaft, a pair of spaced cheek plates on the shaft and a series of discs mounted coaxially on the shaft between thecheek plates so as to provide the desired contour for the rotor surface.

3. A wet magnetic separator as claimed in claim 2, in which the pick-off roller is arranged in frictional engagement with at least one of the cheek plates of the rotor so as to be rotated in unison therewith.

4. A wet magnetic separator comprising in combination a magnet having upper and lower poles, a rotor disposed between the poles of the magnet so that lines of magnetic force will pass between the poles through said rotor, means for rotating said rotor, a table onto which a slurry of the material to be treated is fed, a section of the table passing between the rotor and the lower pole in such manner that the components of the slurry in passing along said section will be separated magnetically into two groups, the said section of the table being closer to the surface of the rotor than to the surface of the lower pole, means to adjust the water content of the slurry fed onto the table, a first launder to collect the nonmagnetic components of the slurry which pass over the end of said table, a strongly magnetized pick-off roller disposed beyond the end of said table and having a surface in close proximity to the surface of the rotor whereby the magnetic components of said slurry adhering to the rotor pass beyond the end of said table are magnetically attracted to the surface of said pick-off roller, means to rotate the pick-off roller in the opposite sense to said rotor, means adapted to remove the said magnetic components from the surface of the pick-off roller, and a second launder to receive the magnetic components removed from the pick-off roller.

References Cited in the file of this patent UNITED STATES PATENTS 832,823 Wait Oct. 9, 1906 FOREIGN PATENTS 35,538 Sweden Sept. 24, 1913 175,765 Germany Mar. 18, 1904 250,080 Germany Oct. 28, 1911 145,442 .Great Britain Nov. 18, 1920

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