RU2635314C1 - Device for dense medium separation of material - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: device comprises a bath tapering downwardly, having a loading device in the upper part and an overflow board on the opposite side of the bath for unloading the float product and an opening in the lower part connected to a discharge pipe for unloading the drowned product. The device is equipped with oscillating screens for float and drowned fractions, a drowned product level sensor and a control unit. The outlet of the discharge pipe is located above the mesh of the oscillating screen for the drowned product. The control unit is connected to the level sensor and to the oscillating screen for the drowned product with the possibility of adjusting the frequency of oscillations of the screen mesh, thereby regulating the discharge speed of the drowned product and maintaining the level of the drowned product at the bottom of the bath. The bath has the shape of a pyramid turned upside down, while the bath wall on the side of the loading device has an arc shape concave into the bath in its vertical section. The bath wall on the side of the tail board and the adjacent side walls are flat and located at an angle of 45-60° to the horizon. A valve is installed at the outlet of the discharge pipe. A magnetic lock connected to the control unit is installed on the discharge pipe with the possibility of regulating the flow velocity of the magnetite slurry and the drowned product. The discharge pipe is located with an inclination angle of the axis to the horizon from 90 to 45°. On the side of the tail board of the bath there are revolving arms.

EFFECT: increasing the efficiency of material separation, reducing the consumption of the suspension.

7 cl, 1 dwg

Description

The invention relates to the field of mineral processing, and in particular to the process of separation of materials (ore, coal, etc.) by density in a heavy medium in a separator bath.

In industry, several types of heavy-medium separators are used. They are distinguished by the shape of the bath and mechanical devices for unloading drowned separation products, such as scraper conveyors, wheeled buckets, vanes, etc. These devices solve the problem of unloading a sunken product, but at the same time they cause problems with violation of a quiet hydrodynamic regime in the separator bath and periodic repair of these mechanical unloading devices that require the separator to stop.

Known separator for the enrichment of wide classes of fineness of minerals with different specific gravities, including a deep conical bath, a loading device, with the discharge of a pop-up product (light fraction) through a drain threshold with a heavy suspension, with the discharge of a sunken product (heavy fraction) through a pipe at the bottom of the bath , the discharge end of which is raised above the level of the bottom of the bath (US patent 2,954,870, issued 04.10.1960).

In this separator, the particle size range of the enriched material particles (ore, coal, etc.) can be 6 × 1/4 ''.

Existing gravitational heavy-medium processes in separator baths have proven the effectiveness of their use for separating particles of different specific gravities with particle sizes greater than 1/4 ''. In all these processes, particles of different specific gravities are immersed in a heavy liquid having a specific gravity higher than that of the light fraction and lower than that of the heavy fraction. Separation is carried out using the properties of light particles to float and heavier particles to sink in a liquid heavy medium of intermediate density.

In practice, a liquid heavy medium is an aqueous suspension of finely divided solids with a high specific gravity, for example magnetite. Essentially, not only to maintain the specified specific gravity of the heavy medium constant, but also to supply power, unload the surfaced and sunken products without interfering with the uniform hydrodynamic flow of the suspension with the material. This is a prerequisite for the optimal operation of the separator. The use of magnetite as a weighting agent in a suspension has found wide application because, using its magnetic properties, it is easy to separate it from the material on magnetic separators and return it to the process of preparing a magnetite suspension.

The disadvantage of the above separator is a deep bath, which implies a relatively high pressure of the suspension at the bottom of the bath and, accordingly, a high rate of its expiration. To solve this problem, the end of the discharge pipe for the sunken product is raised above the bottom of the bath to create back pressure. But this solution implies the need to supply under excess pressure an additional amount of the suspension into the pipe only for unloading heavy sunken material. Another disadvantage of a deep bath requires a suspension at the bottom of the bath to create an upward flow in order to prevent separation of the suspension (magnetite precipitation) along the depth of the bath.

The objective of the invention is to reduce energy consumption and increase reliability by eliminating additional mechanical devices that raise the sunken product above the suspension level in the bath, increasing the efficiency of unloading the sunken product directly onto the dewatering device (screen) from the bottom of the separator bath by gravity, without the use of mechanical unloading devices and without supplying an additional amount of suspension to unload the sunken product.

The problem is solved by a device for heavy-medium separation of material, containing a tapering downward bath, having a loading device in the upper part and an overflow threshold on the opposite side of the bath for unloading the surfaced product and an opening in the lower part connected to the unloading pipe for unloading the drowned product, while according to the invention, the device is equipped with vibrating screens for floating and sunken products, a level sensor of the sunken product and a control unit, output one hole of the discharge pipe is located above the screen of a vibrating screen for a sunken product, and the control unit is connected to a level sensor and a vibrating screen for a sunken product with the ability to control the oscillation frequency of the screen, thereby controlling the rate of unloading of a sunken product and maintaining the level of a sunken product at the bottom of the bath .

The technical result of the invention is to reduce the consumption of the suspension due to the elimination of the need to supply an additional amount of the suspension under pressure to unload the drowned heavy fraction of the material by ensuring its discharge directly to the dewatering device (screen) from the bottom of the bath by gravity. For this purpose, a height-controlled layer is created from a sunken product of a source material of wide size from 6 to 200 mm in the lower part of the bath, which is unloaded by gravity through a discharge pipe at the bottom of the bath directly onto a screen of a vibrating screen to separate and wash the heavy medium suspension from the sunk product. A sunken product from the pipe is discharged directly onto a sieve of a drain-washing screen. The rate of unloading of a sunken product from the pipe and the height of its layer in the lower part of the bath is also regulated by a change in the vibration frequency of the screen.

In particular cases of execution, the device is characterized in that:

- the bath has the shape of a pyramid, turned apex down, while the wall of the bath from the side of the loading device has in its vertical section the shape of an arc concave into the bath;

- the wall of the bath from the drain threshold side and adjacent side walls are flat and are located at an angle of 45-60 degrees to the horizon;

- a valve is installed at the outlet of the discharge pipe.

- a magnetic shutter is installed on the discharge pipe, connected to the control unit with the possibility of controlling the flow rate of the magnetite suspension and the sunken product;

- the discharge pipe is located vertically or with an angle of inclination of the axis to the horizon from 90 to 45 degrees;

- from the drain threshold of the bath placed a rowing device.

The invention is illustrated in the drawing.

The device for heavy-medium material separation contains a bath 1, into which the starting material 2 and a magnetite slurry are fed 3. The bath 1 has an outlet in the lower part connected to an unloading pipe 4 located vertically or with an angle of inclination of the axis to the horizontal from 90 to 45 degrees. A valve 5 is installed at the outlet of the pipe 4. In the upper part, the bath 1 has a loading device 6 and a drain threshold 7 on the opposite side. The device contains two drainage and washing vibrating screens 8 and 9 for floating and sunken products, respectively. The vibration screen 8 is located next to the drain threshold 7, and the vibration screen 9 is located directly under the outlet of the discharge pipe 4. In the bath 1, a level sensor 10 of the sunken product is installed. A magnetic shutter 11 is mounted on the discharge pipe 4. The control unit 12 is connected to a level sensor 10, with a vibrating screen 9, with a magnetic shutter 11 and a medium density measurement sensor 13.

The sump 14 with magnetite suspension is connected via a pump 15 to the suspension supply pipe 16 to the loading device 6 and bath 1. The suspension trays 17 and 18 from the vibrating screens 8 and 9 are connected by a pipe 19 to supply the suspension to the sump 14.

Above the drain threshold 7, a rowing device 20 is installed to facilitate the unloading of large pieces of the surfaced product.

A device for heavy medium separation by the example of coal enrichment works as follows. The source material (coal) 2 enters the bath 1 in the form of a pyramid with the top pointing down. The front wall of the bath 1 of the separator is curved in an arc inside the bath. The wall of the bath 1 from the side of the drain threshold 7 and adjacent side walls are flat and are located at an angle of 45-60 degrees to the horizon.

Together with coal 2, the separator 6 is fed by the pump 15 from the sump 14 through the pipe 16 to the conditional magnetite suspension 3 of a given density into the loading device 6, which fills the separator bath 1. The starting material is a mixture of light (coal) and heavy (rock) fractions. The optimal ratio of the volume of the suspension to the volume of the original solid material should be in the range of 3: 1-4: 1. In the separator bath 1, material separation occurs: coal floats (black color of the particles in the drawing), and the rock sinks and sinks to the bottom of the separator bath 1 (white particles in the drawing). Surfaced clean coal, together with most of the suspension (up to 80% of the total incoming volume), is discharged through an adjustable drain threshold 7 using a paddle rowing device 20 to a horizontal vibrating screen 8 to separate clean coal from the suspension and dehydration. Dehydrated coal is conveyed to the finished goods warehouse by a conveyor.

The angle at the top of the bath 1 (pyramids) is selected from the condition of ensuring the sliding of the sunken rock along the faces of the bath 1 to the discharge pipe 4.

At the beginning of operation, the valve 5 on the discharge pipe 4 is closed until the pipe 4 is filled with rock, which will fix the level sensor 10, which is, for example, a rod with a limit switch and a float. After this, the valve 5 opens, and the sunken product (rock), together with a certain amount of suspension (not more than 20% of the total volume entering the separator), is discharged to a horizontal vibrating screen 9. At screen 9, the rock is separated from the suspension, washed from particles of adhered magnetite and dehydrated. Then the rock is conveyed by conveyor to the rock hopper and transported to the waste dump. The magnetite suspension separated from the enrichment products on the vibrating screens 8 and 9 is collected in pallets 17 and 18 of the screens 8 and 9 and is discharged through a pipe 19 into the sump 14 of the conditioned suspension for feeding back to the separator bath 1.

Automatic adjustment by unloading of a sunken product is carried out by the control unit 12, which controls the opening of the valve 5, the magnetic shutter 11 to form an adjustable magnetite plug in the discharge pipe 4, the vibration frequency of the screen 9 in order to adjust the speed of discharge of the rock from the discharge pipe 4.

The density sensor 13, in the form of, for example, a differential pressure sensor is necessary to control the density of the medium, the level of suspension with the material in the bath 1 of the separator.

The height of the layer of the sunken product at the bottom of the bath 1 and in the pipe 4 is maintained at a constant level, ensuring optimal flow rate of the suspension through the discharge pipe 4 (by filtering the suspension through the gaps between the particles of the sunk product and its entrainment during its movement in the pipe 4), not exceeding 20 % of the volume of suspension supplied to the separator bath. The size of the cross section of the discharge pipe 4 is selected from the condition of 3 times exceeding the maximum size of a piece of a drowned product to ensure free unloading of the material. In order to limit the flow rate of a heavy-medium suspension through the lower discharge pipe 4 with a flow rate of up to 20% or less of the total volume of the suspension supplied to the separator bath 1 with the starting material, the following conditions must be fulfilled.

1. The depth of the separator bath 1 should not be more than 7 times the size of the largest piece of the starting material in order to reduce the pressure of the suspension at the inlet to the discharge pipe 4 at the bottom of the bath and to provide optimal conditions for the separation of material along the depth of the bath 4 and at the same time to avoid separation of the suspension along bath depth 4.

2. The front wall of the separator bath 1 has a concavity inside the bath to form a predominantly horizontal surface flow of slurry in the upper part of the separator bath. The length of the discharge pipe for a drowned product, its angle of inclination are determined depending on the particle size distribution of the drowned product and its density, on the composition of the heavy medium, its viscosity and density, i.e. from the coefficient of filtration of a heavy medium suspension through the pore space of a sunken product in the discharge pipe 4.

3. At the bottom of the discharge pipe 4, an insert of non-magnetic material is made on which a magnetic shutter 11 for magnetite suspension (based on electromagnets or permanent magnets) is installed. The magnetic shutter 11, acting on the magnetic component of a heavy medium (magnetite), forms an adjustable magnetic ring-shaped tube inside the pipe 4, as a result, the narrowing of the pipe channel 4 and the flow rate of the sunken material and suspension from the discharge pipe 4 can be controlled.

4. The sunken product from the pipe 4 is discharged directly onto a sieve of a drainage-washing vibration screen 9. The speed of unloading the sunken product from the pipe 4 and the height of its layer in the lower part of the bath 1 is controlled by a change in the vibration frequency of the screen 9. The novelty of the proposed device (separator) consists in the application gravity discharge of a drowned product of a large size from 6 to 200 mm directly to a vibrating screen 9. To limit the flow of magnetite suspension with a drowned product, an adjustable mag itny shutter 11 installed on the discharge pipe 4, a shallow bath of the separator 1, the curved inside anterior wall bath separator 1 and, if necessary, installed at an angle to the horizontal unloading tube 4.

The proposed device in comparison with the considered prototype will significantly reduce the consumption of heavy medium suspension through the lower discharge pipe 4 and will provide a higher separation efficiency of the material in the bath 1 of the separator due to the reduction of turbulence of flows in the bath 1 of the separator. Compared to widespread separators with mechanical unloading of a sunken product, downtime and costs due to the repair of these devices will be eliminated, reliability will be increased, and energy consumption will be reduced.

Claims (7)

1. Device for heavy medium separation of material, containing a tapering downward bath having a loading device in the upper part and an overflow threshold on the opposite side of the bath for unloading the pop-up product and an opening in the lower part connected to the discharge pipe for unloading the sunken product, characterized in that the device is equipped with vibrating screens for floating and sinking fractions, a level sensor for the drowned product and a control unit, the outlet of the discharge pipe is located The screen is connected to a vibrating screen for a drowned product, and the control unit is connected to a level sensor and a vibrating screen for a drowned product with the ability to control the oscillation frequency of the screen, thereby controlling the rate of unloading of a drowned product and maintaining the level of a drowned product at the bottom of the bath. 2. The device according to p. 1, characterized in that the bathtub has the shape of a pyramid, turned apex downward, while the wall of the bathtub from the side of the loading device has in its vertical section the shape of an arc concave inside the bathtub. 3. The device according to p. 1, characterized in that the wall of the bath from the side of the drain threshold and adjacent side walls are flat and are located at an angle of 45-60 ° to the horizontal. 4. The device according to claim 1, characterized in that a valve is installed at the outlet of the discharge pipe. 5. The device according to claim 1, characterized in that a magnetic shutter is installed on the discharge pipe, connected to the control unit with the possibility of controlling the flow rate of the magnetite suspension and the sunken product. 6. The device according to p. 1, characterized in that the discharge pipe is located with an angle of inclination of the axis to the horizon from 90 to 45 °. 7. The device according to p. 1, characterized in that from the side of the drain threshold of the bath placed a rowing device.

Images