WO2010054847A1

WO2010054847A1 - Crossed structure magnetic separator with tetrapolar rotary magnetic circuit and annular rotors

Info

Publication number: WO2010054847A1
Application number: PCT/EP2009/008159
Authority: WO
Inventors: José Pancrácio RIBEIRO; Márcio Augusto Teixeira RIBEIRO
Original assignee: Allmineral Aufbereitungstechnik Gmbh & Co. Kg
Priority date: 2008-11-17
Filing date: 2009-11-16
Publication date: 2010-05-20
Also published as: BRPI0805659A2; AU2009315919B2; AU2009315919A1

Abstract

A magnetic separator having at least one horizontal rotor of highly magnetically permeable material arranged within an external housing and having at least a pair of electromagnets consisting of a magnet yoke around the arm of which a coil is arranged, the electromagnets having alternate north and south polarities, whereas around the periphery of the rotor a series of boxes containing plates are mounted and a feed device for the raw material to be separated is arranged before each electromagnet in the rotating direction of the rotor and a collecting device for the magnetic particles as separated is arranged behind each electromagnet in the rotating direction of the rotor outside the magnetic force lines running from the north pole towards the south pole as formed by the electromagnets, is characterized in that at least four electromagnets (30) with alternate north and south polarities are arranged in the periphery of the rotor (4) in a cross like structure such that the magnetic force lines (3) run from the two north pole electromagnets (30) located opposite to each other to the two south pole electromagnets (30) located in between in a tangential course of the rotor (4).

Description

Crossed structure magnetic separator with tetrapolar rotary magnetic circuit and annular rotors

D e s c r i p t i o n

The invention relates to a magnetic separator having at least one horizontal rotor of highly magnetically permeable material arranged within an external housing and having at least a pair of electromagnets consisting of a magnet yoke around the arm of which a coil is arranged, the electromagnets having alternate north and south polarities, whereas around the periphery of the rotor a series of boxes containing plates are mounted and a feed device for the raw material to be separated is arranged before each electromagnet in the rotating direction of the rotor and a collecting device for the magnetic particles as separated is arranged behind each electromagnet in the rotating direction of the rotor outside the magnetic force lines running from the north pole towards the south pole as formed by the electromagnets.

A magnetic separator showing the afore-mentioned features is disclosed in US 3 830 367. The structure of the known magnetic separator is determined by two rotors mounted at vertical space locations on a shaft being hold in an external housing. A pair of diametrically opposed electromagnets are provided adj acent the both rotors whereas each electromagnet is consisting of an U-shaped heavy magnet yoke around the arms of which are electromagnetic coils. The both electromagnets have alternate north and south polarity in the plane of each rotor. Around the periphery of the rotors are mounted a series of plate boxes containing grooved plates. Above these plates is mounted a feed device by which feed slurry is fed into the plate boxes. Directly below the plate boxes are collecting launders which alternatively receive non-magnetic products, middling products and magnetic particles. As after feeding of the plate boxes these plate boxes come into the influence of the electromagnet the magnetic particles immediately adhere to the plate surfaces with non-magnetic particles passing straight through. Following this the plate boxes depart from the influence of the electromagnet and approaching the mid-point between the south pole and north pole electromagnet they reach a zone of substantially zero magnetism where the magnetic particles release from the plate surface so that they can be received by the respective launder. Due to the arrangement of two electromagnets adjacent one rotor two complete separation cycles occur during each full revolution of the respective rotor and due to the existence of two rotors with two electromagnets related to each of them four separation cycles are established with the known magnetic separator.

The current demand of the industry in the field of mining, principally in the sector of mineral processing of increasingly poorer materials, is for more compact equipment with a greater production capacity and easier maintenance. Currently, in the type of equipment presently known and/or in use, the construction is always performed with the use of magnetic poles mounted in diametrically opposite positions in relation to the rotor and in each rotor there are two feeding points and at least two collecting points. The rotors are in the form of solid discs to enable a run of the magnetic force lines from the north pole electromagnet to the south pole electromagnet located in diametrically opposite position.

Therefore it is an object of the invention to improve production capacity of a magnetic separator having the general features as mentioned afore. Further objects may consist in reducing the weight of the equipment and facilitating the maintenance.

The solution of this object is provided by the features of claim 1 . Advantageous embodiments of the invention are given within the subclaims. The invention has its basic idea that at a magnetic separator showing the features of the preamble of claim 1 at least four electromagnets with alternate north and south polarities are arranged in the periphery of the rotor in a crosslike structure such that the magnetic force lines run from the two north pole electromagnets located opposite to each other to the two south pole electromagnets located in between in a tangential course of the rotor. Herewith a duplication of the number of magnetic poles and a duplication of feeding and collection points is foreseen, so that the production capacity is increased.

As the magnetic force lines are running only in a tangential course of the rotor it is possible to give the rotor an annular structure and insofar according to one embodiment of the invention the rotor is in the form of an annular member whereby the magnetic force lines run through the respective section of the annular member which during rotation thereof is located between the neighboured electromagnets respectively. This annular rotary form of the rotor is lighter and therefore more economical.

As it is principally known from the state of art according to one embodiment of the invention two rotors are arranged on top of one another with a vertical distance whereas four electromagnets are related to each rotor and whereas the electromagnets arranged in the same vertical plane are formed by an U- shaped yoke with different magnetic polarity so that a displacement of 180 electrical degrees is realized between the pole directed to the upper rotor in relation to the pole directed to the lower rotor, thereby allowing the complete close of the magnetic force lines between the two rotors. This idea makes it possible to have a high production equipment with a substantial economie of materials and with a better use of the installation area.

According to a further embodiment of the invention it can be provided that yoke and coils of each electromagnet are arranged within a separate U-shaped housing part consisting of a bottom part, a cover part and a sidewall extending between bottom and cover part and carrying the electromagnets whereas each housing part is removably fixed to a central housing forming the support for the at least one rotor. Insofar it is possible to remove each single housing part carrying the respective electromagnet with coil from the equipment in order to exchange the coil without the need to remove the rotors and, therefore, to disassemble most of the machine as this happens with the current equipment.

The invention shall not be limited to a construction of such machine having four electromagnets. Even more than four electromagnets may be arranged within such machine in a symmetrical manner if the dimension of such machine would make this generally possible.

In the drawings a magnetic separator according to the state of art and according to one exemplary embodiment of the invention are shown which are to be described next. In the drawings:

fig. 1 shows the basic construction of a magnetic separator according to the state of art,

fig. 2 shows the basic construction of the magnetic separator according to one embodiment of the invention,

fig. 3 shows in different views the main parts of the separator according to figure 1 ,

fig. 4 shows the main parts of the separator according to figure 2 in vi ews as shown in figure 3 ,

fig. 5 shows a view of the equipment according to figure 2 while removing one housing part carrying at least one electromagnet from the machine. As far as a current model of a known magnetic separator is shown within figure 1 inside a housing 10 two rotors 2 are arranged one on top of the other, both rotors 2 being held by a shaft 1 1 which is arranged within the housing 10. The shaft 1 1 is connected to an electric motor 12 for rotating the shaft 1 1 and thereby the rotors 2 fixed thereto. Two electromagnets 30 are arranged adjacent to each of the both rotors 2 each electromagnet 30 consisting of a U- shaped magnet yoke 9 around the arms of which coils 1 are arranged. In total the machine as shown in figure 1 has four electromagnets 30. The rotors 2 are formed as solid discs.

As it can be additionally taken from figure 3 around the periphery of each rotor 2 are mounted a series of boxes 28 having mounted plates 29 in their inner. Feeding points 5 for the raw material to be separated are arranged adj acent to each electromagnet 30 before such electromagnet in the rotating direction (arrow 3 1 ) of the rotor 2. On the other side of each electromagnet 30 a medium washing point 6 is arranged in order to support the separating process. The magnetic force lines 3 run from the north pole electromagnet 30 to the south pole electromagnet 30 mounted in diametrically opposite position thereby crossing the solid disc forming the rotor 2. It can be detected from figure 3 that during rotation always a section of the rotor 2 being located between the both electromagnets 30 is lying outside of the magnetic force lines 3 and within this section collecting points 7 are located for washing and collecting the concentrate consisting of the magnetic particles washed out of the boxes 28.

The construction and the function of the known magnetic separator as described afore can be taken more in detail from the US 3 830 367 the disclosure of which hereby is included into this description by reference.

The construction of the magnetic separator in accordance with the invention can be seen within figures 2 and 4 respectively which show the separator in the same views as figures 1 and 3 referring to the state of art do. Referring first to figure 2 four electromagnets 30 are arranged with respect to each rotor 4 in a crosslike manner, so that in total eight electromagnets are mounted within the machine. The electromagnets 30 have alternate north and south polarities which leads to an arrangement whereas two electromagnets 30 having north poles and two electromagnets 30 having south poles are situated in diametrically opposite positions respectively. Each electromagnet 30 has the same structure as already described and known from US 3 830 367 and is surrounded by a separate housing part 8 which has an U-shaped form and is consisting of a bottom part 14, a cover part 1 5 and a sidewall 16 extending there between. The four housing parts 8 at their inner ends are connected to a central housing part 17 which serves for holding the shaft 1 1 and the electric motor 12.

As it can been best from figure 4 each rotor 4 is in the form of an annular ringlike member. Having a hole 24 in his middle spokes 26 lead from the solid outside ring 25 to the center of the rotor 4 where the shaft 1 1 for carrying the respective rotor 4 is located. The magnetic force lines 3 that come from the north pole of the respective electromagnet 30 divide in half and follow in the direction of the two adjacent south poles of the neighboured electromagnets 30 using only the periphery of the annular rotor 4 as a route for this purpose. It is this characteristic of magnetic flow circulating only in the external region of the annular rotor 4 and with a quantity of force lines corresponding to half of the force lines which come from the poles that allows the same to be constructed in an annular form, because the magnetic force lines do not diametrically cross it as this is the case with the models of the type of equipment currently known from the state of art.

According to the doubling of the electromagnets 30 also the necessary feeding points 5, the medium washing points 6 and the collecting points 7 are doubled as this can be seen from figure 4 compared with figure 3. Therefore the equipment represented in figure 4 has doubled the processing capacity in relation to the current model of the same size as shown in figure 3. As it can been seen from figure 5 the maintenance of the equipment, especially replacement of the coils 1 , is facilitated because the housing parts 8 each carrying two electromagnets 30 relating to the two rotors 4 can be removed separately from the central housing part 17 so that free access is given to each coil 1 .

The features of the subject matter disclosed in the foregoing description, in the patent claims, in the abstract and in the drawings can be important individually as well as in any combination for the implementation of the invention in its different embodiments.

Claims

C l a i m s . Magnetic separator having at least one horizontal rotor of highly magnetically permeable material arranged within an external housing and having at least a pair of electromagnets consisting of a magnet yoke around the arm of which a coil is arranged, the electromagnets having alternate north and south polarities, whereas around the periphery of the rotor a series of boxes containing plates are mounted and a feed device for the raw material to be separated is arranged before each electromagnet in the rotating direction of the rotor and a collecting device for the magnetic particles as separated is arranged behind each electromagnet in the rotating direction of the rotor outside the magnetic force lines running from the north pole towards the south pole as formed by the electromagnets, characterized in that at least four electromagnets (30) with alternate north and south polarities are arranged in the periphery of the rotor (4) in a cross like structure such that the magnetic force lines (3) run from the two north pole electromagnets (30) located opposite to each other to the two south pole electromagnets (30) located in between in a tangential course of the rotor (4) .

2. Magnetic separator according to claim 1 characterised in that the rotor (4) is in the form of an annular member whereby the magnetic force lines (3) run through the respective section of the annular member which during rotation thereof is located between the neighboured electromagnets (30) respectively.

3. Magnetic separator according to claim 1 or 2, characterized in that two rotors (4) are arranged on top of one another with a vertical distance whereas four electromagnets (30) are related to each rotor (4) and whereas the electromagnets (30) arranged in the same vertical plane are formed by an U-shaped yoke (9) with different magnetic polarity so that a displacement of 180 electrical degrees is realized between the pole directed to the upper rotor (4) in relation to the pole directed to the lower rotor (4).

4. Magnetic separator according to one of the claims 1 - 3 , characterized in that yoke (9) and coils ( 1 ) of each electromagnet (30) are arranged within a separate U-shaped housing part (8) consisting of a bottom part ( 14), a cover part ( 15) and a sidewall (16) extending between bottom and cover part and carrying the electromagnet (30) whereas each housing part (8) is removably fixed to a central housing (17) forming the support for the at least one rotor (4).