RU2748911C1 - Method of extracting magnetic fraction from suspension flow and device for implementation thereof - Google Patents

Abstract

FIELD: mining.SUBSTANCE: proposed group of inventions relates to concentration of minerals, namely, to magnetic separation. Method of extracting the magnetic fraction from the suspension stream involves feeding the suspension, bringing it into rotary motion, applying the magnetic field on the suspension stream, withdrawing the separation products along the axis of rotation of the suspension stream. Alternating or constant magnetic field is applied from above and coaxially to the rotating flow so that the magnetic field lines cross the rotating flow of the suspension. Magnetic fraction is discharged through drainage of magnetic hydrocyclone passing along axis of magnetic system and geometrical centre of magnetic field, and nonmagnetic fraction is discharged through sand nozzle. Method is implemented with the help of a device including a cylinder-conic case, loading and drain branch pipes, a sand nozzle and a magnetic system. Magnetic system is made in the form of electromagnetic system with magnetic core or without it, which is supplied with alternating or direct current, or from permanent magnets. Is installed coaxially to drain branch pipe on hydrocyclone cover. In the discharge branch there are holes for concentrate unloading with possibility of adjustment of total area of unloading holes. In order to adjust the total area of unloading holes, the device is made with an internal insert into the drain branch pipe, the movement of which allows changing the area of holes for unloading the concentrate and correcting the operating mode of the magnetic hydrocyclone.EFFECT: technical result is higher quality of magnetic product (concentrate) while maintaining high specific efficiency of magnetic separation process.3 cl, 1 ex, 2 dwg

Description

The invention relates to the field of mineral processing, in particular, to methods and devices for magnetic separation.

Known devices for continuous extraction of the magnetic fraction from the mineral suspension of magnetic and non-magnetic particles, which are a hydrocyclone equipped with a magnetic system, including: a cylindrical-conical body, a supply pipe located tangentially to the cylindrical part of the body; a drain pipe located along the vertical axis partially in the cylindrical part of the body and fixed to its cover; sand nozzle; magnetic system located on the conical or cylindrical part of the body, inside or outside. [A.S. USSR No. 1535633 M. Cl. В03С 1/00 of 04/25/88]

The disadvantage of this device is the joint extraction of large non-magnetic mineral particles and magnetic fraction, i.e. the magnetic fraction is extracted from the coarse non-magnetic fraction, which reduces the quality of the concentrate.

The closest in technical essence and the achieved result is a device in which the magnetic system is located outside on the conical part of the hydrocyclone and the unloading of the magnetic fraction in accordance with the separation method is carried out through a sand nozzle [A.S. USSR No. 522857 M. Cl. В03С 1/00: В03В 5/34 dated 02.28.1972 (prototype)].

The disadvantage of this device and the method it implements for extracting the magnetic fraction from the rotating flow of the suspension is the poor-quality separation of polydisperse suspensions of minerals, consisting of particles of different sizes, due to the incomplete opposition of the vectors of magnetic and centrifugal forces in the separation zone, which consists in the fact that the action co-directed at different angles vectors of magnetic and centrifugal forces leads to the fact that under the action of centrifugal force all relatively large and heavy non-magnetic mineral particles enter the magnetic product, contaminating the magnetic fraction.

The technical objective of the invention is to increase the selectivity of the separation of magnetic minerals from polydisperse suspensions at a high specific productivity of the process.

This goal is achieved by changing the directions of action of the magnetic and centrifugal forces to mutually opposite and placing a magnetic system above the rotating flow of the suspension, creating an alternating magnetic field so that the lines of the magnetic field intersect the rotating flow of the suspension. The gradient of the alternating magnetic field inside the hydrocyclone body is directed opposite to the direction of the sum of the vectors of the centrifugal force and the gravitational force, and the outlet of the magnetic fraction (product) is redirected through the drain pipe using the openings for unloading the concentrate.

The possibility of adjusting the operating mode of the magnetic hydrocyclone is carried out by a drain pipe equipped with a device for adjusting the total area of the unloading holes, for example, an internal insert with slotted cuts, the movement of which changes the overlapping area of the holes.

The technical result consists in improving the quality of the magnetic product (concentrate) while maintaining a high specific productivity of the magnetic separation process in the hydrocyclone and is achieved by the fact that in the magnetic separation method, which includes feeding a polydisperse suspension containing magnetic material into the upper cylindrical part of the magnetic hydrocyclone, separating magnetic material (product) in the flow of a suspension from a non-magnetic one is carried out in the upper separating cylindrical part of the hydrocyclone under the action of magnetic forces, centrifugal force and gravitational force, unloading is carried out due to the difference in the pressure of the suspension in the internal volume of the hydrocyclone and the drain pipe with the clarified part of the suspension through the discharge holes in the drain pipe, the removal of the non-magnetic fraction (product) is carried out through the sand packing under the action of centrifugal forces.

The technical result is also achieved by the fact that the magnetic hydrocyclone is equipped with a magnetic system located on top of the hydrocyclone cover, made in the form of an electromagnetic system with a magnetic core (for example, in the form of a solenoid) or without it, or from permanent magnets (the goal is to save electricity), located coaxially above the rotating flow of the suspension in such a way that the lines of the magnetic field intersect the rotating flow of the suspension, as well as a drain pipe with discharge holes located under the hydrocyclone cover to remove the magnetic product from the cylindrical part of the body.

The technical essence is:

- in the fact that for a given location of the magnetic system relative to the rotating pulp flow, the magnetic force vector is opposite to the centrifugal force vector, as well as the corresponding gradients of these forces. Thus, the most complete separation of magnetic and non-magnetic fractions is ensured;

- the fact that the use of an alternating magnetic field provides a greater mobility of the suspension, selectivity of separation and prevents clogging of the discharge holes with floccules of the magnetic product;

- the fact that the use of holes in the drain pipe for unloading (removing) magnetic particles from the separation space of the cyclone provides a high productivity of the process and selectivity of extracting magnetic material into the concentrate;

- the fact that the use of a high-speed flow of the clarified part of the suspension to remove magnetic particles from the hydrocyclone ensures their accelerated removal from the separation space, eliminating the clogging of the separation space.

The essence of the invention is illustrated by drawings, where FIG. 1 shows a cross-sectional and top view of a magnetic hydrocyclone; FIG. 2 shows the direction of action of the magnetic and centrifugal forces in the hydrocyclone and the direction of movement of the suspension particles;

The device consists of a magnetic hydrocyclone body - 1, a drain pipe - 2, equipped with discharge holes - 3, a magnetic system - 4, an inlet pipe - 5, a sand nozzle - 6.

The method is implemented as follows.

The suspension is prepared by mixing the pre-crushed iron-containing product with water in a ratio of 1/10 to 3/10 and fed by a dredge pump to a hydrocyclone, which sets it in rotary motion. From above, an alternating magnetic field is coaxially applied to this device so that the magnetic field lines intersect the rotating flow of the suspension. The interaction of the rotating suspension flow and the magnetic field leads to an increase in the concentration of magnetic particles in the paraxial region of the flow and nonmagnetic ones at its periphery. The removal of the magnetic fraction is carried out along the axis of the rotating flow of the suspension through the discharge of the magnetic hydrocyclone, which coincides with the axis of symmetry of the magnetic system, and the non-magnetic fraction is removed in the opposite direction (for example, through a sand packing).

The device works as follows.

The suspension enters the cylindrical part of the magnetic hydrocyclone body - 1 through the inlet pipe - 5 and enters the zone of action of magnetic and centrifugal forces in the separation space, acquiring a rotational motion. Under the action of a magnetic force, magnetic particles are concentrated near the magnetic system under the hydrocyclone cover around the drain pipe - 2, displacing non-magnetic particles, which, under the action of centrifugal force, are thrown to the walls of the hydrocyclone and then move into the conical part of the hydrocyclone, where they are removed through a sand nozzle - 6. Magnetic particles under the influence of the magnetic field gradient, they tend to the geometric center of the magnetic field and under the influence of the pressure difference between the flows of the suspension in the cylindrical part of the hydrocyclone and in the discharge nozzle, they are carried out through the discharge holes - 3 in the discharge nozzle by the flow of the part of the suspension clarified in the hydrocyclone.

Example 1

The model of the device, which is a magnetic hydrocyclone with an inner diameter of 29 mm and a drain pipe with a diameter of 10 mm, was tested in laboratory conditions on an artificial mixture of magnetite and quartz in a ratio corresponding to the Fe content of 43.98% and 18% solid at a particle size of 70% of class -0 , 04 mm. The upper size limit was 0.12 mm.

The slurry was fed through the inlet pipe using a slurry pump with a capacity of 800 l / h. The magnetic system was powered by alternating current through an autotransformer, providing a magnetic induction of 0.35 T directly under the hydrocyclone cover in the center. As a result, two products were obtained: a concentrate with a content of 54.7% Fe and tailings with a content of 25.96% Fe. The extraction of iron into the concentrate was 81.0%, the solid productivity was 144 kg / h. When conducting a similar experiment on the device, according to and.with. USSR No. 522857, a concentrate with a lower iron content - 48.7% was obtained.

Claims (3)

1. A method for extracting a magnetic fraction from a suspension flow, including feeding a suspension, setting it in rotary motion, applying a magnetic field to the suspension flow, removing separation products along the axis of rotation of the suspension flow, characterized in that an alternating or constant magnetic is applied from above and coaxially to the rotating flow. field in such a way that the lines of the magnetic field intersect the rotating flow of the suspension, the magnetic fraction is removed through the drain of the magnetic hydrocyclone passing along the axis of the magnetic system and the geometric center of the magnetic field, and the non-magnetic fraction is removed through the sand packing. 2. A device for extracting a magnetic fraction from a slurry flow, including a cylindrical-conical body, loading and drain pipes, a sand nozzle and a magnetic system, characterized in that the magnetic system is made in the form of an electromagnetic system with or without a magnetic core, powered by alternating or direct current , or made of permanent magnets, is made coaxial to the drain pipe and is located on the hydrocyclone cover, and holes for concentrate discharge are made in the drain pipe with the possibility of adjusting the total area of the discharge openings. 3. The device according to claim 2, characterized in that in order to adjust the total area of the discharge openings, the device is made with an internal insert in the drain pipe, the movement of which makes it possible to change the area of the openings for unloading the concentrate and adjust the operating mode of the magnetic hydrocyclone.

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