RU2739980C1 - Electrodynamic and magnetic separation method and device for implementation thereof - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to separation of materials both by electric conductivity in a rotating magnetic field and by magnetic properties, and can be used both for dry separation of loose magnetic and nonmagnetic materials, and for wet magnetic separation of the same materials in mining, metallurgy and other industries. To implement electrodynamic and magnetic separation method material is supplied to conveyor belt arranged at angle to horizon and connecting two non-magnetic rotating driving and driven drum. During rotation of magnetic system in driven drum on tape other than magnetic there formed is electromagnetic field, under action of which dry material or in form of pulp is first divided by conductivity into two fractions. First fraction is inert materials which immediately fall into the separation products receivers. Second fraction is electrically conducting magnetic and electroconductive nonmagnetic materials, moving further on the conveyor belt to the zone of action of the magnetic system of the driving drum, which forms during rotation except magnetic, electromagnetic field operating in the mode of repulsion of weakly magnetic particles and nonmagnetic electroconductive particles and exceeding force of attraction to magnets. Speed of the conveyor belt is set such that gravitation forces of the electrically conductive magnetic particles and friction forces acting on these particles exceed the force of their attraction to the magnet. Material is divided into two fractions - electroconductive nonmagnetic and electrically conductive magnetic, which fall into appropriate separation products. In each of the drums there are magnetic systems made in the form of rotors with permanent magnets of alternating polarity. Rotors and non-magnetic driving drum, which moves conveyor belt, are made with possibility of their rotation at different speed and in different sides from individual motors with frequency-controlled drives. Device is equipped with vibrating feeder with feed tray for dry material and receiving hopper with feed tray for pulp.

EFFECT: higher efficiency of separation of initial material and efficiency of separation process.

3 cl, 3 dwg

Description

The invention relates to the field of separation of materials both by electrical conductivity in a rotating magnetic field and by magnetic properties, and can be used both for dry separation of bulk magnetic and non-magnetic materials, and for wet magnetic separation of the same materials in mining, metallurgical and other industries industry.

The known Method of magnetic separation (RU No. 2392056, publ. 20.06.2010), including the supply of pulp to the zone of influence of a non-uniform magnetic field and the withdrawal of separation products. The separation of the pulp is carried out into three flows in one cycle, while in the first flow, strong magnetic particles are extracted, acting on the pulp with a weak magnetic field through the air gap between the pulp and the conveyor belt, decreasing in the direction of the pulp movement, in the second flow - weakly magnetic particles, acting on the strong magnetic field through the air gap, decreasing in the direction of the pulp movement until it fully contacts the conveyor belt at the end of the magnetic impact zone, and into the third stream - the sludge, and the conveyor belt is rotated towards the pulp flow.

The disadvantage of this method is the impossibility of separating dry material, and also there is no electrodynamic separation, which affects the quality of the separation of the material.

A known method of extracting particles of noble metals from metal-bearing sands (RU No. 2427431, publ. 27.08.2011), including disintegration, screening, separation of the magnetic fraction and gravitational enrichment, and after the separation of the magnetic fraction, the sands are classified by size +0.5 mm and - 0.5 mm, sands with a grain size of +0.5 mm are subjected to gravity concentration, and sands with a grain size of 0.5 mm, and after drying, the tailings of gravity concentration are subjected to electrodynamic separation by direct action on conductive particles by a pulsed traveling magnetic field of high intensity and gradient.

The disadvantage of this method is the work only on the wet method of separating particles of noble metals, multistage enrichment process, and there is no electrodynamic separation.

The known Method of magnetic separation of bulk products (RU No. 2229343, publ. 05/27/2004), including the supply of the product to the surface of a non-magnetic rotating drum, inside which is placed a magnetic system of permanent magnets of alternating polarity in the direction of movement of the product, the deposition of a magnetic product under the influence of magnetic field forces and cleaning the magnetic product on the surface of this drum, directing the separation products to the receivers. The cleaning is carried out in a magnetic field, the frequency of polarity reversal of which is greater than the frequency of reversing the polarity of the magnetic field in the zone of deposition of the magnetic product.

The disadvantage of this method is the impossibility of its operation in the wet way, and also there is no electrodynamic separation.

Known electrostatic separator (RU No. 2018374, publ. 30.08.1994) for the separation of bulk materials and the separation of fine powders into conductors and dielectrics, consisting of a sealed housing, an electric field source, a device for supplying the source material and discharge of separation products.

A significant disadvantage of this separator is its low productivity and a limited upper limit for the size of non-conductive particles (no more than 3 mm).

Known electrodynamic separator (SU No. 1715426, publ. 28.02.1992) for the extraction of non-ferrous metals from industrial waste and the extraction of valuable components from crushed scrap of household radio equipment. The separator contains a loading and unloading hopper, a conveyor made of dielectric material, made in the form of a disk with unloading windows for removing non-conductive particles using a scraper, a running magnetic field inductor located under the conveyor coaxially with it and made in the form of a disk with a drum in which grooves permanent magnets with alternating polarity are placed on the inductor disk at an angle to the diametral axis so that their length overlaps the area of the conveyor not occupied by the reloading windows.

The disadvantages of this device include the complex design of the device for the output of the non-conductive fraction.

Known electrodynamic separator (SU No. 1773488, publ. 07.11.1992) for the extraction of particles of non-ferrous metals from industrial waste and purification of non-ferrous materials before their further processing. The separator includes a working body in the form of a disk made of a dielectric material, located under the feeder with the possibility of rotation, a running magnetic field inductor coaxially installed under it, a scraper and receivers of separation products. When the separator is switched on, the disc inductor and the disc working body with the power distributor are driven into rotation, which feeds the initial material from the feeder to the working body. When the inductor rotates, a high-frequency magnetic field is created, which causes eddy currents in the electrically conductive particles, as a result of the interaction of which with the rotating magnetic field of the inductor, an electrodynamic force arises, pushing the electrically conductive particles of non-ferrous metals in the direction of decreasing the magnetic field intensity in the direction from the center to the periphery of the disk working body. Moving under the action of an electrodynamic force, electrically conductive particles of non-ferrous metals move through the non-conductive material in contact with them, which is retained on concentric corrugations of the disk working body. Having passed the concentric corrugations (jumping over them), electrically conductive particles move freely to the edge of the working body and are removed by scrapers into the chambers of the discharge hopper. And non-conductive particles remaining on the surface of the working body are removed with a scraper into the chamber for non-conductive particles. The disk working body rotates at a low speed, which makes it possible to ignore the centrifugal forces acting on the separated particles.

The disadvantage of this separator is the low efficiency of extraction of small class of non-ferrous metals and low productivity of the device due to the low speed of rotation of the disk and the use of scrapers to remove material. If the speed of rotation of the working body is increased to values at which the centrifugal force is large enough to cause self-unloading of the material without the participation of scrapers, then in this case the separation products will mix, which will lead to a decrease in the separation efficiency.

The closest to the claimed device is a tape magnetic separator (RU No. 2400307, publ. 09/27/2010), which includes two non-magnetic rotating drums, each of which contains magnetic systems made of permanent magnets, receivers of separation products, and the magnets are located so that their magnetic moments are directed in one direction, and the axis of rotation coincides with the axis of rotation of the drums and passes through their geometric axes with the possibility of their rotation from individual drives with a variable frequency towards the movement of the conveyor belt.

The disadvantage of this solution is the impossibility of creating an electromagnetic field, as a result of which there is no qualitative separation of the material.

The objective of the present invention is to increase the efficiency of separation of the source material and the productivity of the separation process in one enrichment cycle by separating into inert, magnetic and non-magnetic electrically conductive fractions.

The problem is solved using the proposed method of electrodynamic and magnetic separation, including the supply of material to the area of action of a magnetic system of permanent magnets of alternating polarity placed inside a non-magnetic rotating drum. Moreover, first the material enters the conveyor belt connecting two non-magnetic rotating driving and driven drums in each of which magnetic systems are located inside, which have independent drives. When the magnetic system rotates in the driven drum on the tape, in addition to the magnetic field, an electromagnetic field is formed under the action of which the dry material or in the form of a pulp is first separated by conductivity into two fractions, the first fraction is inert materials that immediately fall into the receivers of separation products, and the second fraction is electrically conductive magnetic and electrically conductive non-magnetic materials that move further on the conveyor belt into the zone of action of the magnetic system in the driving drum, which, during rotation, forms, in addition to the magnetic, also an electromagnetic field operating in the mode of repulsion of weakly magnetic particles and non-magnetic electrically conductive particles and exceeding the force of attraction to magnets, and the speed the conveyor belt is installed so that the gravitational forces of the electrically conductive magnetic particles and the friction forces acting on these particles exceed the force of their attraction to the magnet, the material is separated into two fractions - electrically conductive non-magnetic and and conductive magnetic, which fall into the appropriate receivers of separation products.

The problem is solved using the proposed device for electrodynamic and magnetic separation, including a conveyor belt, two non-magnetic rotating drums, each of which contains magnetic systems, receivers of separation products, and the magnetic systems are made in the form of rotors with permanent magnets of alternating polarity, in addition, rotors and a non-magnetic drive drum driving the conveyor belt are made with the possibility of their rotation at different speeds and in different directions from individual motors with variable frequency drives, and the device is equipped with a vibrating feeder with a feeding chute for dry material, and a receiving hopper with a feeding chute for pulp. The conveyor belt is made with corrugated sides.

The proposed method and device, in comparison with the known solutions, allows to increase the productivity and efficiency of material separation, to ensure work with a wider range of materials: grain size from 5 microns to 10 mm. The device not only separates materials by conductivity in a rotating magnetic field, but also separates electrically conductive non-magnetic materials from electrically conductive magnetic materials, which significantly expands the scope of this technology. Also, in contrast to the known solutions, the separation of materials is carried out not only in dry but also in wet mode. The method and device for electrodynamic and magnetic separation are energy saving, because electricity consumption per 1 ton of processed material is 0.1 kW. For use in industrial production, the proposed device, in comparison with the known solutions, has a simpler, but at the same time, more perfect design.

The invention is illustrated by drawings.

FIG. 1 shows a structural diagram of the device.

FIG. 2 shows the magnetic separation mode, in which the oscilloscope shows the absence of Foucault currents in the working area of the rotor.

FIG. 3 shows the mode of electrodynamic separation, the rotation of the rotor with permanent magnets creates an electromagnetic field, in which the oscilloscope shows the presence of Foucault currents.

The device for electrodynamic and magnetic separation includes a conveyor belt 1 located on the frame with corrugated sides, rotating on two non-magnetic rotating drums: a slave 2 with a magnetic system 3 located in it and a magnetic system 4 in a master 5, magnetic systems are made in the form of rotors with constant magnets of alternating polarity, receivers of separation products 6, 7, 8, 9, vibrating feeder 10 with a feeding chute 11 for bulk material, a receiving hopper 12 and a feeding chute 13 for feeding the slurry in the wet separation process. Magnetic systems 3, 4 in the form of a rotor, and a non-magnetic driving drum 5 driving the conveyor belt 1 are made with the possibility of their rotation at different speeds and in different directions from individual motors with variable frequency drives (not shown in Fig. 1).

The method of electrodynamic and magnetic separation is carried out using the device as follows.

The device for electrodynamic and magnetic separation works in 2 stages. In a first step, electrically conductive magnetic and non-magnetic materials are separated from inert non-conductive and non-magnetic materials, and in a second step, electrically conductive magnetic materials are separated from electrically conductive non-magnetic materials. The device is made with the possibility of carrying out the separation of the material both dry and wet.

In places where there are rivers, lakes, water wells and where ecology permits, the wet method is used. In this case, the starting material is mixed in a slurry mixer with water and through a hose (pipe) (not shown in Fig. 1) enters the receiving hopper 12 and through the feeding chute 13 the slurry is directed to the conveyor belt at a speed of 1-2 meters per second zone of the magnetic system 3 of the non-magnetic driven drum 2, which rotates clockwise. The electrically conductive material is accumulated on the conveyor belt 1. The optimum rotation speed of the magnetic system 3 is 3000 rpm. Due to the fact that the magnetic system 3 is located inside the non-magnetic drum 2, and the conveyor belt 1 is also made of a dielectric material, in the working area of the magnetic system 3, in addition to a magnetic and electromagnetic field, is created, which is confirmed by an oscilloscope indicating the presence of Foucault currents Fig. 2 or lack thereof FIG. 3. The electromagnetic field induces an electromotive force (EMF) in electrically conductive particles, which allows them to be affected by the same alternating field. The device is configured in such a way that inert non-magnetic non-conductive particles are directed to the receiver of separation products 6, and electrically conductive magnetic and electrically conductive non-magnetic particles of material, under the influence of an electromagnetic field, move on the conveyor belt 1, moving at a speed of 1-2 revolutions per minute and enter the working area of the magnetic systems 4 of the driving non-magnetic drum 5. Electrically conductive non-magnetic particles (non-ferrous metals), due to the repulsive force of Lorentz, are actively pushed out and directed to the corresponding receiver of separation products 9. Electrically conductive magnetic particles are captured by the magnetic field and move down the belt and due to the fact that the conveyor belt 1 comes off the leading non-magnetic drum 5 and the effect of the magnetic field decreases, then the electrically conductive magnetic particles fall off due to the forces of gravity from the conveyor belt 1 and are sent to the receiver of separation products 8.

Where the wet method is not acceptable, the dry separation method is used. When processing the feedstock of the fine fraction, the material is fed into the vibrating feeder 10 and then into the feeding chute 11, which provides its uniform supply to the conveyor belt 1 into the working zone of the magnetic system 3 of the driven non-magnetic drum 2. The further process is similar to the wet method.

The device can work with crushed ore, with man-made materials, with concentrates. When working with iron ore concentrate, in order to increase the Fe content, only the magnetic system 3 of the driven non-magnetic drum 2 can be used. The original concentrate is fed through the vibrating feeder 10 and then the feeding chute 11 to the conveyor belt 1. In this case, the conveyor belt 1 rotates counterclockwise. The magnetic system 3 also rotates counterclockwise. In this case, strongly magnetic particles are directed to the auxiliary receiver of separation products 7, and weakly magnetic particles containing quartz actively bounce off the magnetic system and are directed to the receiver of separation products 6 for inert particles with the possibility of their subsequent crushing and additional enrichment.

Example.

Samples were taken from the tailing dump of the Olenegorsk GOK with a Fe content of 12.0%, sifted through a 72 micron sieve. The original concentrate through the vibrating feeder 10 and then the feeding chute 11 was fed to the conveyor belt 1 into the working area of the magnetic system 3. The conveyor belt 1 rotates counterclockwise. The magnetic system 3 also rotates counterclockwise. In this case, strongly magnetic particles, in this case Fe, are directed to the auxiliary receiver of separation products 7, and weakly magnetic particles containing quartz and other impurities actively bounced off the magnetic system 3 and were directed to the receiver of separation products 6 for inert materials. As a result, an iron ore concentrate with an Fe content of 70.3% was obtained during a single cleaning, and all the Au in an amount of 0.03 g / t was sent to receiver 6. At the same time, a concentrate with an Fe content of 66.5% is produced at the main production of Olenegorsk GOK ...

Further, the separation products entering the separation products receiver 6 were recycled. The device is configured in such a way that the rotation of the magnetic system 3 is carried out clockwise, as a result of which weakly magnetic and electrically conductive particles moving on the conveyor belt 1 were sent to the bunker 9, and the inert particles to the receiver 6. As a result, the Au content was 0.8 g / t , thus, having enriched 26.7 times. According to the current standards, commercial gold mining is carried out with an Au content of 0.1 g / t. In the given example, the proposed device made it possible to obtain Au in the amount required for industrial mining from iron ore dressing wastes.

And with a single cleaning on the proposed device for electrodynamic and magnetic separation of the concentrate sample from Lebedinsky GOK with an Fe content of 68.5%, an iron ore concentrate with an Fe content of 70.5% was obtained. That allows you to get iron by direct reduction, and not melting in a blast furnace.

The proposed method and device for electrodynamic and magnetic separation can increase the efficiency of the separation process by maximizing the extraction of particles of magnetic fractions from the flow of bulk material or pulp flow and to obtain three fractions in one enrichment cycle on one separator: inert, electrically conductive magnetic and electrically conductive non-magnetic fractions.

Claims (3)

1. A method of electrodynamic and magnetic separation, including the supply of material to the area of action of a magnetic system of permanent magnets of alternating polarity, placed inside a non-magnetic rotating drum, characterized in that first the material falls on a conveyor belt located at an angle to the horizon and connecting two non-magnetic rotating leading and a driven drum, in each of which there are magnetic systems inside that have independent drives, and when the magnetic system rotates in the driven drum, an electromagnetic field is formed on the tape in addition to the magnetic field, under the action of which the dry material or in the form of a pulp is first separated by electrical conductivity into two fractions, the first fraction - inert materials that immediately fall into the receivers of separation products, and the second fraction - electrically conductive magnetic and electrically conductive non-magnetic materials, which move further on the conveyor belt into the zone of action of the magnetic system of the driving drum on, forming during rotation, in addition to a magnetic field, an electromagnetic field operating in the mode of repulsion of weakly magnetic particles and non-magnetic electrically conductive particles and exceeding the force of attraction to magnets, and the speed of the conveyor belt is set such that the gravitational forces of electrically conductive magnetic particles and friction forces acting on these particles, exceeded the force of their attraction to the magnet, and the material is separated into two fractions - electrically conductive non-magnetic and electrically conductive magnetic, which fall into the corresponding receivers of separation products. 2. A device for electrodynamic and magnetic separation, including a conveyor belt, two non-magnetic rotating drums, each of which contains magnetic systems, receivers of separation products, characterized in that the magnetic systems are made in the form of rotors with permanent magnets of alternating polarity, one of the drums is made leading, in addition, the rotors and a non-magnetic driving drum driving the conveyor belt located at an angle to the horizon are made with the possibility of their rotation at different speeds and in different directions from individual motors with variable frequency drives, and the device is equipped with a vibrating feeder with a feeding tray for dry material and a receiving hopper with a feed chute for pulp. 3. The device according to claim 2, characterized in that the conveyor belt is made with corrugated sidewalls.

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