RU2733354C1 - Magnetic gravity separator with filtration device - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: present invention relates to the field of beneficiation of minerals, in particular to equipment for dressing highly magnetic ores, and can be used to improve the quality of finely dispersed ferromagnetic minerals and materials by reducing the weight fraction of silicon dioxide. Magnetic-gravitational separator includes cylinder-conical case made of nonmagnetic material, initial suspension supply device, devices for supply of flushing water and discharge of separation products, and magnetic system. Inside in separator housing upper cylindrical part filtration device is installed, which is located above the upper edge of the magnetic system and above the lower cut of the apparatus for feeding the initial suspension and is in form of a barrier-former from non-magnetic material with thickness of not less than 4 mm. Width of barrier shaper horizontally makes 100–200 mm. Barrier shaper is made in the form of a truncated hollow cone with height of 150–180 mm, wherein the lower large base is located above the level of location of the magnetic system and above the lower cut of the apparatus for feeding the initial suspension, and along the upper base circumference a hollow pipe out of nonmagnetic material is installed and fixed, at that, pipe radius is 20–40 mm. Barrier shaper is made in the form of a flat ring with a hollow tube of non-magnetic material, at that the pipe is installed and fixed from above along the inner edge of the ring, and the pipe radius is 20–40 mm. Barrier shaper is made in the form of a flat ring with width of 100–200 mm, besides, the ring has small flanging upwards by 20–40 mm.

EFFECT: obtaining high-quality magnetite concentrates with low weight fraction of silicon dioxide to 1_5 % and lower, as well as improving processing properties of the dressing process.

4 cl, 6 dwg

Description

The invention relates to the field of mineral processing, in particular to equipment for the beneficiation of highly magnetic ores and can be used to improve the quality of the extracted finely dispersed ferromagnetic minerals and materials by reducing the mass fraction of silicon dioxide.

Over the past 25 years, the iron content in mined ores in the world has decreased by 1.3 times, and the proportion of impurities has increased significantly, which led to an increase in energy costs in metallurgical production. Magnetic separation is one of the most critical operations in the dressing of iron ores, the efficiency of which determines the technological parameters of the dressing process.

Magnetic-gravity separators are known from the prior art, which, as a rule, have a typical configuration - a vessel for washing ore, a product loading device, a magnetic system, a product removal device, a water supply and removal device.

The closest to the claimed solution is a magnetic-gravity separator (RF patent for invention No. 2133155, IPC В 03 С1 / 00, publ. 20.07.1999), which includes a cylindrical-conical body made of non-magnetic material, devices for supplying the initial suspension, washing water and withdrawal of separation products, a magnetic system installed outside and inside the housing, while the magnetic system is made in the form of coaxially located electromagnetic coils designed to increase the production of concentrate. However, the disadvantages of such separators include the low quality of the product obtained when separating naturally depleted ores with an increased content of impurities.

A technical problem, the solution of which is provided by using the claimed invention, is the creation of a magnetic-gravity separator, which makes it possible to improve the quality of the product obtained in conditions of concentration of even depleted ore.

The technical result is to improve the technological parameters of the enrichment process and obtain high-quality magnetite concentrates with a reduced mass fraction of silicon dioxide to 1.5% and below.

The specified technical result is achieved by introducing a filtration device into the design of the magnetic-gravity separator, installed inside the cylindrical part of the separator body and made in the form of a barrier-shaper of the upward flow of washing water.

The claimed invention is illustrated by drawings, which show:

Figure 1 is a general view of the claimed separator (cross-section);

Fig. 2 is a schematic view of a filtering device;

Fig. 3 is a diagram of the ingress of silicon dioxide into the magnetite concentrate;

4 is a phase diagram for a suspended bed of ferrimagnetic particles;

Fig. 5 - data of the calculation of the model of the motion of the liquefied stabilized ferrimagnetic suspension in the upward flow for the speed of 0.014 m / s;

6 shows the velocity distribution in the upstream of the separator.

The claimed magnetic-gravity separator (Fig. 1) is a structure consisting of a cylindrical-conical body 1 made of non-magnetic material, with an electromagnetic system coaxially installed on the outside of the body, from one or more coils 2 with autonomous magnetic field strength control units 3, a supply pipe 4 with a loading device 5, a drain chute 6, an unloading branch pipe 7, a device for supplying wash water 8 with tangentially mounted branch pipes 9 and a filtration device 10.

In contrast to the closest analogue, the claimed magnetic-gravity separator additionally contains a filtration device 10 installed inside the upper cylindrical part of the separator body and made in the form of a barrier-shaper of the upward flow of washing water, and the filtration device is installed above the level of the magnetic system and above the lower cut of the device feeding the initial suspension, and the width of the barrier-former is in the range of 100-200 mm.

Structurally, the filtration device (Fig. 2) can have the form of a hollow truncated cone with a height of 150-180 mm, made of a non-magnetic material (stainless non-magnetic steel 12X18H10T) with a thickness of at least 4 mm, while the smaller base of the cone is on top, and along its edge from above along a pipe (toroid) of non-magnetic material (stainless non-magnetic steel 12X18H10T) with a radius of 20-40 mm is welded to the circumference.

Also, the filtration device can be in the form of a flat ring with a shaper made in the form of a hollow tube (toroid) of non-magnetic material (stainless non-magnetic steel 12X18H10T), which is welded along the inner edge of the ring (circumferentially).

In addition, the filtration device can be made in the form of a flat ring of non-magnetic material (stainless non-magnetic steel 12X18H10T) with a slight smooth radial bend (flange) of the C-shape along the inner edge of the ring upwards by 20-40 mm, while the thickness of the ring should be not less than 4 mm.

The filtration device 10 provides a laminar movement of the wash water for the translational removal of impurities into the "tails". The presence of a filtration device in the magnetic-gravity separator (MGS) creates and forms a zone where ferromagnetic particles captured by the magnetic field are separated from fine impurities and aggregates that were not carried by the upward flow of the separator into the “tails”.

If there is a filtration device in the separator, the ingress of impurities into the final product is limited by the surface of the vertical layer, which is located below the barrier along the walls of the separator, while without a filtration device, layer-by-layer accumulation of impurities occurs in the product. A diagram of the ingress of silicon dioxide into the magnetite concentrate is shown in Fig. 3. In the upper part of the separator ("Impurity zone" - painted over with a grid), where the effect of magnetic forces is minimal, and where a liquefied layer of ferrimagnetic particles is formed, the main contamination of the product (concentrate) occurs.

In this part of the magnetic-gravity separator, due to the increase in the cross-section at the place where the "fur coat" concentrate ends, vortices arise, in which small non-magnetic and intergrowth fractions are present, which freely settle on the inner layer of the magnetite concentrate and then encapsulate, "freeze »When going down in an enhanced magnetic field.

Filtration device:

- allows to form a separation zone, where the ferromagnetic particles captured by the magnetic field and moving towards the magnetic system are separated from the fine impurity and intergrowths that were not carried out by the ascending flow of the separator into the "tails";

- does not allow the formed concentrated suspension of magnetite to capture intergrowths and fine-grained non-ferromagnetic impurities due to an obstacle in the form of an overhanging barrier, which significantly improves the quality of the product.

Figure 4 shows a phase diagram for a suspended layer of ferromagnetic particles, according to which the authors selected the upward flow rate to perform calculations of the height of the barrier-shaper of the filtration device.

The authors calculated a 3D model of the movement of a liquefied stabilized ferromagnetic suspension in an upward flow in the SolidWorks ver. 15 software for a speed of 0.014 m / s, which is shown in Fig. 5, where changes in the directions of the upward flow and its transition through the device shaping barrier are visible filtration. The obtained data allow choosing the optimal place for installing the filtration device in the magnetic-gravity separator.

Figure 6 shows the result of the calculation performed in the SolidWorks ver.15 program, where it is seen how the flow rates are distributed inside the magnetic-gravity separator in the presence of a filtration device and in the absence of a filtration device. Calculations show that the height of the shaping barrier for the filtration device should be in the range of 150-180 mm in order to obtain an improvement in product quality.

The presence of a filtration device in the magnetic-gravity separator makes it possible, without changing the algorithm of the MGS operation, to improve the quality of the obtained magnetite concentrate due to a more perfect purification of the product from fine impurities (silicon dioxide) and intergrowths (quartzites).

The magnetic-gravity separator works as follows.

An electric current is supplied to the electromagnetic coil 2, the value of which is regulated through the control units 3 in order to create a low-gradient magnetic field of 50-100E in the working area. The initial suspension through the feed pipe 4 enters the loading device, made in the form of a cone-shaped tube 5, from which with centrifugal rotation it is evenly distributed along the radius of the body, making a spiral movement due to the tangential feed. Under the influence of the electromagnetic field and gravitational force, ferromagnetic particles and impurities in the form of various mixed enlargements, aggregates (floccules) begin to move down an expanding spiral, but the ascending flow of wash water prevents falling, due to which a suspended layer of ferromagnetic particles is formed above the lower cut of the loading device. a well-defined upper border (Fig. 3). The flushing water entering through the nozzles 9 and the device 8 creates a centrifugal upward flow in the separator due to the tangential supply, which destroys the enlargements, aggregates (floccules) formed from magnetite by a magnetic field, by breaking the pore channels, releasing intergrowths and various impurities into the upward flow , along with which non-magnetic particles and their poor intergrowths with magnetite are carried out into the drain chute 6, and heavier purified ferromagnetic particles, forming a suspended layer, are captured by the magnetic field and move to the walls of the separator.

The magnetic system at the walls of the magnetic-gravity separator creates a magnetic field, the strength of which decreases inversely with the square of the distance. After the capture of ferromagnetic particles by the magnetic field, they are more and more attracted to the walls of the separator, where the maximum electromagnetic field is present. Floccules, which are oval and round in shape, float to the walls of the separator and rotate around their axis, but when captured by a magnetic field, they stabilize (stop rotating) and begin to orient themselves along the lines of the force field, stick together and form threads that stretch and begin to stick together, forming a concentrated suspension (60-70% solid) in the form of a "fur coat" up to 100 mm thick (depending on the field strength).

This suspension (magnetite concentrate) occupies the entire internal space at the walls of the separator, slides under its own gravity along the walls to the bottom of the separator and is removed from the separator through the branch pipe 7. At the top, the "coat" of the separator from magnetite is limited by the magnetic field of the coil and the formed fluidized layer of ferromagnetic particles, which in an upward flow is in a stable state with the following ratios of the acting forces.

For magnetic particles: FM <Fr, FM + Fr> Fn.

For weakly magnetic particles: FM <Fr; FM + Fr <Fn.

For non-magnetic particles: Fn> Fr,

Where

FM — magnetic force acting on a particle, N;

Fg is the gravitational force of the particle, N;

Fn - force of the ascending water flow, N.

At a field strength of more than 150 Oe, exceeding the established permissible values, the destruction of aggregates (floccules) stops and the layer freezes, that is, no separation occurs.

Adjusting the values of the magnetic field strength allows you to control the separation process and determine the optimal parameters for the selective separation of the non-magnetic and intergrowth fractions from magnetite particles. This makes it possible to intensify the process of magnetic-gravity separation and control the likelihood of the removal of intergrowths with a predicted magnetite content.

According to the calculations of the applicant, the magnetite concentrate obtained using the claimed device will contain total iron 67.4%, silicon dioxide 1.5% and free 5.07%, in the size class plus 0.045 mm, while without a filtration device, the content of dioxide silicon in magnetite concentrate is 2.5 times higher and amounts to 3.75% (magnetite characteristics are taken from the Sokolovsko-Sarbait mining and processing plant).

The claimed solution has been disclosed with respect to its preferred embodiments, but similar embodiments are also possible without going beyond the scope of the present invention.

Thus, the combination of the claimed features allows solving the problem and improving the quality of the product obtained even from depleted ore.

Claims (4)

1. Magnetic-gravity separator, including a cylindrical-conical body made of non-magnetic material, a device for feeding the initial suspension, a device for supplying washing water and removing separation products, a magnetic system, characterized in that a filtration device is installed inside the upper cylindrical part of the separator body, which is located above the upper edge of the magnetic system and above the lower cut of the device for feeding the initial suspension and is made in the form of a barrier-shaper made of non-magnetic material with a thickness of at least 4 mm, while the width of the barrier-shaper horizontally is 100-200 mm. 2. Magnetic-gravity separator according to claim 1, characterized in that the forming barrier is made in the form of a truncated hollow cone with a height of 150-180 mm, and the lower large base is located above the level of the magnetic system and above the lower cut of the feed device for the initial suspension, and A hollow pipe made of non-magnetic material is installed and fixed around the circumference of the upper base, while the radius of the pipe is 20-40 mm. 3. Magnetic-gravity separator according to claim 1, characterized in that the barrier-shaper is made in the form of a flat ring with a hollow pipe made of non-magnetic material, while the pipe is installed and fixed from above along the inner edge of the ring, and the radius of the pipe is 20-40 mm ... 4. Magnetic-gravity separator according to claim 1, characterized in that the forming barrier is made in the form of a flat ring 100-200 mm wide, and the ring has a small flange upward by 20-40 mm.

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