RU2469793C1 - Electromagnetic roll separator - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: electromagnetic roll separator includes electromagnetic system with pole piece and roll with annular projections, located between roll and pole piece horizontal vibrating tray, made of two sections: grooved and smooth, grooves of vibrating tray being located opposite roll projections, and loading device, located above vibrating tray. Springs, on which vibrating tray rests, are made at angle 45±5° to horizon, amplitude of fluctuations of vibrating tray must be not less than 0.012 cm.

EFFECT: invention makes it possible to increase efficiency and productivity of dry magnetic separation process.

2 dwg, 1 tbl

Description

The invention relates to magnetic beneficiation and can be used for dry magnetic separation of weakly magnetic ores.

Known electromagnetic roller separator (USSR Author's Certificate No. 574234, class B03C 1/10, 1969), comprising an electromagnetic system with pole tips and a roll mounted for rotation.

Known electromagnetic roller separator (Patent RU No. 13237351, class B03C 1/10, 1982), including a rotatably mounted roll, feeder, receivers of separation products and an electromagnetic system with pole tips.

The disadvantage of these separators is the mutual clogging of the separated fractions, i.e. low separation efficiency.

The closest to the claimed technical solution in terms of technical nature and the effect achieved is an electromagnetic separator (USSR Author's Certificate No. 1599096, class B03C 1/10, 1988) for dry magnetic separation of weakly magnetic ores, consisting of an electromagnetic system with a pole tip, a roll with ring protrusions electrovibration feeder with a horizontal vibratory tray located in the working gap between the pole tip and the roller and consisting of a longitudinal grooved section with holes in the grooves and inclined This smooth area, above which the loading device is installed. Moreover, the grooves of the vibratory tray are located opposite the protrusions of the roll, and the loading device and the tray are installed with the possibility of vertical movement. To receive separation products, a discharge device is located on the pole piece.

The disadvantage of this device is the inability to ensure effective separation of a thick layer of material during the separation of thin particles (<160 μm). The process of separation of fine mineral particles is hindered by the forces of adhesion and dry friction between the particles. Under the action of adhesion forces, particles with different magnetic properties stick together and the particles are clogged together. Dry friction forces prevent the extraction of magnetic particles from the depth of the material layer. Magnetic particles are extracted mainly from the surface of a thin dense layer (monolayer) of bulk material entering the magnetic field of the installation, as a result of which the device has low productivity.

Separation of a thick layer of material (in the context of this application, the term "thick layer" is used as an alternative to "monolayer") on a device selected as a prototype is not possible.

The objective of the invention is to increase the efficiency and productivity of the process of dry magnetic separation of weakly magnetic ores and to ensure the supply of a thick layer of source material (of the order of ten times the particle size) by creating the effect of "vibration fluidization".

If conditions are created under which particles of material moving along the tray of the vibrating feeder will be in suspension (“vibration fluidization”), then the action of the forces of dry friction is weakened, the adhesion of particles caused by the adhesion forces is reduced, and it becomes possible to remove paramagnetic particles from the thickness layer of material, and not just from its surface. This increases the efficiency of the process.

It should be noted that in the prototype the particles also move along the vibratory tray, but without the effect of “vibrational fluidization”, in which the particles of the material most of the time are in suspension.

A known electromagnetic separator for the extraction of fine magnetic material (Patent RU No. 2183997, class B03C 1/24, 2000), in which a "boiling" volume of the separated product is formed due to the formation of a pulsating magnetic field with an alternating gradient. In this case, a "boiling" layer is formed due to the influence of a magnetic field on ferromagnets, contributing to the destruction of magnetic flocs. Those. the device is intended only for the separation of strongly magnetic materials.

Our task is to separate the weakly magnetic (paramagnetic) finely divided materials according to the magnetic properties.

The problem is solved by the proposed design and the choice of device parameters as follows.

The separator (figure 1) incorporates an electromagnetic system 1 with a pole tip 2, a roller 3 with annular protrusions 4, an electrovibration feeder 5 with a vibratory tray 6 located in the gap between the pole tip 2 and the roller 3 and consisting of a longitudinal groove section 7 and an inclined smooth section 8 with a transitional threshold 9, above which a loading device 10 with two interchangeable nozzles is installed. For receiving separation products on the pole piece 2 is a discharge device 11.

The main difference of the claimed device is that the design of the vibrating tray provides the effect of "vibrational fluidization" when passing through it processed material.

As experimental and theoretical studies have shown, ceteris paribus equal to the parameters created by the vibration exciter (namely, the amplitude and frequency of vibration), the angle between the direction of vibration and the surface of the horizontal section of the vibratory tray should be equal to 45 ± 5 °. To do this, the springs 12, on which the vibratory tray rests, must be made at an angle of 45 ± 5 ° to the horizontal. This condition is necessary to obtain the effect of "vibrational fluidization".

Another condition is a certain level of vibration exposure, depending on the amplitude and frequency of vibration (figure 2).

It has been experimentally established that with rectilinear harmonic vibration of the tray and with a thick layer of bulk material (of the order of ten times the particle size), the effect of "vibrational fluidization" is achieved at values of the overload coefficient

where ω is the circular frequency,

g is the acceleration of gravity,

A _h = Acosβ, the amplitude of the transverse (vertical) component of vibration,

A is the amplitude of vibration,

β is the angle of inclination of the springs to the horizon.

From the formula (1) it follows that in order to achieve the effect of “vibrational fluidization” the amplitude of the vibration must be

The horizontal component of the amplitude of the vibration:

At A = 0.015 cm, β = 45 °

and the frequency of vibration of the tray f = 100 Hz (ω = 628 s ^-1 ), which corresponds to a frequency of 50 Hz of alternating current in the electric network, the magnitude of the overload coefficient will be

which according to condition (1) ensures the creation of the effect of “vibrational fluidization”.

In this case, the speed of transportation of the material can be approximately determined by the formula [Vibrations in technology. Reference book, t. 4. M., Engineering, 1980]

This embodiment of the electromagnetic separator and the choice of parameters

And _h ≈ 0.01 cm and f = 100 Hz

the operation of the vibratory feeder allows to obtain the effect of "vibrational fluidization" of the layer and the maximum efficiency of extraction of paramagnetic particles of a large range of particle size and high performance when moving the material in a thick layer.

An electromagnetic separator operates as follows. The source material is fed into the loading device 10 and through the nozzle holes enters the inclined smooth section 8 of the tray 6 and is evenly distributed over its width due to vibration. Through threshold 9, the material is poured into the grooves on the longitudinal grooved section 7. Due to the same vibration, the process of “vibrational fluidization” occurs in the material moved along the tray, the material is loosened and the smallest particles of material are separated from each other due to the fact that the action of dry forces is weakened friction between these particles. In this state, particles of material are delivered into the working gap under the roll 3.

The magnetic fraction attracted to the cylindrical annular protrusions 4 of the roll 3 is removed from the working area and unloaded into the unloading device 11 outside the vibratory tray, and the non-magnetic fraction is unloaded from the end of the vibratory tray into the corresponding compartment of the unloading device.

The results of tests conducted on a laboratory model are summarized in table.

Table The effect of the “vibrational fluidization” effect on the technological parameters of magnetic beneficiation of hematite ore of size class -2 + 0 mm (size content of class -0.16 mm - about 30%) Productivity, kg / h Product Exit, % Fe content,% Fe recovery,% The angle of inclination of the springs β = 45 °. Amplitude A = 0.15 mm (vibrational fluidization) Magn. 37.0 61.7 41.9 11,2 Nemagn. 63.0 50.1 58.1 Ref. 100.0 54,4 100.0 The angle of inclination of the springs β = 45 °. Amplitude A = 0.075 mm (traditional transportation) Magn. 30,4 61.2 34.2 5.5 Nemagn. 69.6 51,4 65.8 Ref. 100.0 54,4 100.0 The angle of inclination of the springs β = 70 °. Amplitude A = 0.15 mm (traditional transportation) Magn. 30,2 59.2 32.9 4.9 Nemagn. 69.8 52.3 67.1 Ref. 100.0 54,4 100.0

Analysis of the indicators given in the table allows us to conclude that the supply of material with a particle size of -2 + 0 mm using the effect of “vibration fluidization” compared with traditional transportation provides a higher iron content in the magnetic product (61.7% against 59, 2% -61.2%) with a productivity 2 times greater and with a higher degree of iron extraction into the magnetic product (41.9% versus 32.9% -34.2%).

Claims (1)

An electromagnetic roller separator, comprising an electromagnetic system with a pole tip and a roller with annular protrusions, located between the roller and the pole tip, a horizontal vibratory tray made of two sections: grooved and smooth, with the grooves of the vibratory tray opposite the protrusions of the roll, and a loading device located above the vibratory tray, characterized in that the springs on which the vibratory tray rests are made at an angle of 45 ± 5 ° to the horizontal, and the amplitude of vibrations of the vibratory tray must not be m less than 0.012 cm.

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