CN111229460A

CN111229460A - Magnetic separation device, magnetic separation method, and method for manufacturing iron source

Info

Publication number: CN111229460A
Application number: CN202010070551.0A
Authority: CN
Inventors: 石田匡平; 西名庆晃; 榎枝成治; 今西大辅
Original assignee: JFE Steel Corp
Current assignee: JFE Steel Corp
Priority date: 2012-10-16
Filing date: 2013-10-11
Publication date: 2020-06-05
Also published as: EP2910309A1; KR102023543B1; EP2910309A4; CN104736249A; KR20150058475A; IN2015MN00483A; JPWO2014061256A1; KR20180035951A; WO2014061256A1; EP2910309B1; JP5773089B2

Abstract

The invention provides a magnetic sorting device, a magnetic sorting method and a method for manufacturing an iron source, which can efficiently separate ferromagnetic particles from powder and granular bodies containing the ferromagnetic particles and can perform magnetic sorting at low cost without complicated processes, waste liquid treatment and the like. The magnetic sorting device of the present invention includes a conveyor belt for conveying powder or granule containing ferromagnetic particles, a hollow conveyor belt guide roller having the conveyor belt wound around a part of the outer periphery thereof and being rotatable, and a magnetic field applying unit provided inside the conveyor belt guide roller, the magnetic field applying unit having a plurality of magnets inside the conveyor belt guide roller and separating the ferromagnetic particles in a magnetic field generated by the magnetic field applying unit. The magnets are arranged so that magnetic poles adjacent in the circumferential direction of the belt guide roller have different magnetic properties, and so that magnetic poles adjacent in the width direction of the belt guide roller have the same polarity.

Description

Magnetic separation device, magnetic separation method, and method for manufacturing iron source

The application is a divisional application of an application with the international application date of 2013, 10 and 11, and the international application number of PCT/JP2013/006109, and the national application number of 201380054216.X, and the invention name of 'a magnetic separation device, a magnetic separation method and a manufacturing method of an iron source'.

Technical Field

The present invention relates to a technique for magnetically sorting (separating) ferromagnetic particles from powder and granular material containing ferromagnetic particles, and for example, relates to a magnetic sorting apparatus (magnetic separator), a magnetic sorting method (magnetic method), and a method for producing an iron source, which are suitable for separating an iron component from slag (slag) which is a by-product of an iron making process.

Background

In the iron making process, slag (steelmaking slag) is produced as a by-product in the preliminary treatment of molten iron or the decarburization process of a converter. The slag is a substance produced by reacting a calcium-based additive added to remove impurities or unnecessary elements in molten iron or steel with the impurities or unnecessary elements. The slag contains a large amount of iron components in addition to the removed impurities or unnecessary elements.

In order to recycle the iron component in the slag, the iron component is separated and recovered. Generally, the separation and recovery of the iron component are performed by the following steps. First, the slag is sieved (sieve) to remove large (several hundred mm) pieces contained in the slag. In the small-sized lumps passed through the screen, since the iron component and the slag component are bonded to each other, coarse crushing (rough crushing) is performed by a hammer mill (hammer mill) or rod mill (rod mill) to have a size of several tens of μm to several tens of mm, and separation of monomers (liberation) (separation of the slag component and the iron component) is promoted. Then, the iron component was separated by a magnetic separator. As the magnetic sorting device, devices of a suspended type (suspended electro magnetic), a cylindrical type (magnetic dry separators), a pulley type (magnetic pulleys), and the like are generally used.

Further, the slag may be heated to separate the iron component alone, and may be cooled for an appropriate period of time and then crushed. By the difference in cooling time, only the adhered slag component can be separated without crushing the iron nuggets, or the slag can be made fine to about several tens of μm.

Regardless of the method, it is self-evident that promoting micronization of the slag promotes monomer separation.

In general, since it is necessary to advance the separation of the monomers in order to increase the recovery rate of the iron component, mechanical crushing is repeated to reduce the particle size of the slag. Or the diameter may be reduced by heat treatment.

In the case of performing magnetic separation for the recovery of iron components, a magnetic separation apparatus such as that shown in fig. 8 has been conventionally used (for example, non-patent document 1). This apparatus is a magnetic sorting apparatus of a pulley type (belt conveyor type), and separates ferromagnetic particles from nonmagnetic particles when a powder or granule a containing ferromagnetic particles is supplied from a supply device 23 onto a conveyor belt 20 and discharged from a conveyor terminal part 27. In the belt guide roller 21 on the conveyor terminal end 27 side, the magnet 22 is disposed in a part of the inner circumferential direction. The magnets 22 are arranged so that magnetic poles adjacent in the circumferential direction of the belt guide roller 21 have different polarities. The magnet 22 is a fixed magnet provided independently from the belt guide roller 21.

In this magnetic sorting apparatus, at the conveyor terminal end 27, the magnetic force of the magnet 22 inside the conveyor guide roller 21 acts on the powder/granular material a on the conveyor 20, the nonmagnetic particles not attracted by the magnet 22 fall first and are collected in the nonmagnetic material collection unit 24y, and the ferromagnetic particles attracted by the magnet 22 fall at a position where the magnetic force is weakened by the partition plate 25 provided below the conveyor guide roller 21 and are collected in the magnetized material collection unit 24 x.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open No. 2006-142136

Patent document 2: japanese laid-open patent publication No. 10-130041

Non-patent document

Non-patent document 1: svoboda, Magnetic technologies for the Treatment of materials, pp.70-72, Kluwer Academic Publishers,2004

Disclosure of Invention

Problems to be solved by the invention

However, as shown in fig. 8, a large amount of powder and granular bodies a are supplied to the conventional magnetic sorting apparatus, and when the layer thickness of the powder and granular bodies a becomes large, the following problems occur. In the micronized powder/grain a, the ferromagnetic particles are in a state of being held by the nonmagnetic particles, and the ferromagnetic particles and the nonmagnetic particles are simultaneously drawn toward the magnet 22, so that the ferromagnetic particles and the nonmagnetic particles are difficult to separate. This is more remarkable as the particle diameter of the powder/granular body a is smaller. In addition, when the layer thickness of the powder based granules a on the conveyor 20 increases due to aggregation phenomenon of fine particles, as shown in fig. 8, the nonmagnetic particles are mixed into the magnetized material collecting portion 24x, and the ferromagnetic particles cannot be appropriately sorted.

In order to solve such a problem, generally, the following countermeasures are required: as shown in fig. 9, the amount of the powder or granule a supplied is reduced by the vibration feeder 26 or the like, and the thickness of the powder or granule layer on the conveyor 20 is reduced to a thickness of, for example, 1 to 2 particles. However, when the supply amount of the powder or granule a is reduced, the performance of sorting ferromagnetic particles can be ensured, but the processing speed is lowered. In the case of magnetic separation of slag, it is necessary to process several tons to several tens tons per hour, and therefore a large amount of magnetic separation must be performed in a short time. Therefore, in the conventional magnetic sorting apparatus as described above, it is difficult to perform magnetic sorting of a large amount of powder and granular bodies a in a short time.

On the other hand, patent document 1 proposes a method of separating foreign matter without excessively crushing slag through a plurality of specific steps, but the method involves a complicated separation process and a problem of high treatment cost. Further, as shown in patent document 2, a wet process is generally applied to avoid aggregation, but there is a problem that the waste liquid treatment cost is enormous.

An object of the present invention is to solve the above-described problems of the prior art, and to provide a magnetic sorting apparatus and a magnetic sorting method that can efficiently separate ferromagnetic particles from powder or granular material even when a large amount of powder or granular material including ferromagnetic particles is processed or when the layer of the supplied powder or granular material is thick, and that can perform magnetic sorting at low cost without requiring complicated steps, waste liquid treatment, or the like.

Means for solving the problems

The present inventors have obtained the following findings regarding magnetic sorting.

When ferromagnetic particles are sorted from a powder or granule in which ferromagnetic particles and nonmagnetic particles are mixed, using a moving magnet, the ferromagnetic particles are first moved so as to be drawn toward the magnet when observing the movement of each particle. The attractive force acting on the ferromagnetic particles changes due to a change in the strength of the magnetic field accompanying the movement of the magnet. When the magnetic field is strong, the ferromagnetic particles are aggregated by the attraction force, whereas when the magnetic field is weak, the ferromagnetic particles tend to be dispersed.

The change in the attractive force exerts an effect similar to vibration on the powder particles, and the change in the strength of the magnetic field is repeated, whereby the sandwiched and clasped state of the nonmagnetic particles by the ferromagnetic particles is eliminated. As a result, separation of ferromagnetic particles and nonmagnetic particles is promoted. Further, since a rotational force is also applied to the ferromagnetic particles due to a change in the direction of the magnetic field, the ferromagnetic particles move toward the magnet while rotating between the nonmagnetic particles. By these 2 effects, ferromagnetic particles are gradually concentrated more toward the vicinity of the magnet, and nonmagnetic particles conversely move from the magnet to the farther side. In this way, ferromagnetic particles and nonmagnetic particles can be separated by utilizing the change in the magnitude and direction of the magnetic field.

Fig. 1(a) to (D) schematically illustrate the above effects. In fig. 1(a) to (D), the magnetic poles of the magnet at the portion facing the powder and granular material are represented as N-pole and S-pole. When the magnet moves from a state in which the ferromagnetic particles on the conveyor 2 are pulled close to each other by the N pole as shown in fig. 1(a) and the gap between the N pole and the S pole is in a state in which the gap faces the powder or granular material as shown in fig. 1(B), the magnitude of the attractive force acting on the ferromagnetic particles changes due to the change in the magnitude of the magnetic field. Then, the ferromagnetic particles are attracted in the direction of the arrow by the change of the magnetic pole from the N pole to the S pole, and move toward the magnet while rolling. Then, as shown in fig. 1(C), the ferromagnetic particles are drawn toward the south pole and move toward the magnet. By repeating the above operation, ferromagnetic particles initially distributed in the entire powder layer are collected on the side of the powder layer closest to the magnet as shown in fig. 1 (D).

This phenomenon inevitably occurs as long as at least one of the magnet and the powder/granular material a moves, and the same applies to the case where only the powder/granular material a moves while the magnet is fixed.

When magnets of the same magnetic pole are moved side by side, the ferromagnetic particles move due to a change in the magnitude of the magnetic field, but a rotational force due to a change in the direction of the magnetic field is not applied to the ferromagnetic particles, and therefore the amount of movement of the ferromagnetic particles decreases, resulting in a decrease in the sorting efficiency.

Although fig. 1(a) to (D) show the case where the magnet moves from the right side to the left side in the figure, the same applies in principle to the case where the magnet moves from the left side to the right side in the figure.

The present inventors have applied the above-described mechanism to a belt conveyor type magnetic sorting apparatus, and have found the following: magnets are provided along the circumferential direction of the conveyor belt guide roller inside the conveyor belt guide roller on the conveyor terminal end side, the magnets being arranged so that adjacent magnetic poles of portions facing the powder or granule are different from each other and adjacent magnetic poles of portions facing the powder or granule in the width direction of the conveyor belt guide roller are the same, and the powder or granule is moved in a magnetic field formed by the magnets, whereby the ferromagnetic particles can be magnetically sorted efficiently. The effect is further improved when the magnitude and direction of the magnetic field acting on the ferromagnetic particles are changed at high speed by rotating the magnet.

The present invention has been made based on such findings, and the gist thereof will be described below.

[1] A magnetic sorting device has:

a first belt conveyor (A) for conveying a powder particle layer containing ferromagnetic particles;

a second belt conveyor (B) which is positioned above the first belt conveyor (A), has a hollow belt guide roller (3) on the start end side of the second belt conveyor (B), and has a belt wound around a part of the outer periphery of the belt guide roller (3) so as to be rotatable; and

a magnetic field applying means comprising a rotatable magnet roller disposed inside the belt guide roller (3), the magnet roller including a plurality of magnets disposed along the outer periphery of the magnet roller, the magnets being disposed so that the magnetic poles adjacent in the circumferential direction of the belt guide roller are different from each other and the magnetic poles adjacent in the width direction of the belt guide roller are the same,

the upper surface of the powder particle layer conveyed by the first belt conveyor (A) is in contact with the lower surface of the start end of the second belt conveyor (B),

the magnetic field intensity at the conveyor belt part in contact with the conveyor belt guide roller (3) is 0.01 to 0.5T,

a magnetic field change frequency F (Hz) defined by the following formula (1) and representing the change of the magnetic field acting on the powder layer from the magnetic field applying means is 170Hz or more,

F＝(x·P)/60…(1)

in this case, the amount of the solvent to be used,

x: speed of rotation (rpm) of magnet roll

P: the number of magnetic poles of the magnet roller (wherein the number of magnetic poles is counted as 1 magnetic pole by a pair of N pole-S pole adjacent in the circumferential direction of the surface of the magnet roller facing the powder particle layer).

[2] The magnetic sorting device of claim 1,

a starting end portion of the second belt conveyor (B) is located at a position above and close to a terminal end portion of the first belt conveyor (A),

the conveyor belts of the first belt conveyor (a) and the second belt conveyor (B) move in the same direction at the terminal end of the first belt conveyor (a) and the start end of the second belt conveyor (B).

[3] The magnetic sorting device of claim 1,

the starting end of the belt conveyor (B) is positioned at a position which is close to the upper part of the conveyor belt of the belt conveyor (A) and between the terminal end of the belt conveyor (A) and the powder and granular body supply device,

the conveyor belts of the first belt conveyor (a) and the second belt conveyor (B) move in opposite directions at the terminal end of the first belt conveyor (a) and the start end of the second belt conveyor (B).

[4] The magnetic sorting device of

claim

2 or 3,

the conveyor belt and the conveyor belt guide roller (3) of the second belt conveyor (B) are made of a non-metal, and the conveyor belt guide roller (3) is set as a non-driven roller.

[5] The magnetic sorting device of

claim

2 or 3,

a magnetized material recovery unit is provided below a conveyor terminal end portion of the belt conveyor (B), and a non-magnetized material recovery unit is provided below a conveyor starting end portion of the belt conveyor (B).

[6] A magnetic sorting method, wherein,

use of the magnetic sorting device according to any one of claims 1 to 5,

the powder or granule is supplied from a supply device onto the belt conveyor (A) in a layer thickness larger than the diameter of the smallest particles contained in the powder or granule.

[7] A method for producing an iron source from a by-product of an iron-making process by using the magnetic separation device or the magnetic separation method according to any one of claims 1 to 6.

Effects of the invention

According to the present invention, even when a large amount of powder or granule containing ferromagnetic particles is processed or when the layer of supplied powder or granule is thick, ferromagnetic particles can be efficiently separated from the powder or granule containing ferromagnetic particles in one separation step, and magnetic sorting can be performed at low cost without requiring complicated steps or waste liquid treatment.

Drawings

Fig. 1(a) to (D) are explanatory views schematically showing the operation of the magnetic sorting apparatus of the present invention.

Fig. 2 is an explanatory view showing one embodiment of a magnetic sorting apparatus and a magnetic sorting method using the same according to embodiment 1 of the present invention.

Fig. 3 is a perspective view showing the structure of the conveyor belt guide roller of the magnetic sorting apparatus according to embodiment 1 of fig. 2.

Fig. 4 is an explanatory view showing a modification 1 of the magnetic sorting apparatus according to embodiment 1 of the present invention and a magnetic sorting method using the apparatus.

Fig. 5 is an explanatory view showing a modification 2 of the magnetic sorting apparatus according to embodiment 1 of the present invention and a magnetic sorting method using the apparatus.

Fig. 6 is a perspective view showing a structure of a conveyor belt guide roller in modification 3 of the magnetic sorting apparatus according to embodiment 1 of fig. 2.

Fig. 7 is an explanatory view showing an embodiment of a magnetic sorting apparatus and a magnetic sorting method using the same according to embodiment 2 of the present invention.

Fig. 8 is an explanatory view showing a state of use of the conventional magnetic sorting apparatus and a large amount of powder and granular material processed by using the apparatus.

Fig. 9 is an explanatory view showing a conventional magnetic sorting apparatus and a state of use when a small amount of powder or granular material is processed by using the apparatus.

Detailed Description

The magnetic sorting apparatus and the magnetic sorting method of the present invention are techniques for separating ferromagnetic particles from powder or granule containing ferromagnetic particles by magnetic force. The magnetic sorting device of the present invention includes a belt for conveying powder or granular material, a rotatable conveyor belt guide roller around a part of the outer periphery of which the belt is wound, and a magnetic field applying unit including a plurality of magnets provided inside the guide roller. The magnets are arranged along the circumferential direction of the conveyor belt guide roller so that the magnetic poles of the portions facing the powder and granular material alternate, and so that the magnetic poles of the portions facing the powder and granular material in the width direction of the conveyor belt guide roller are the same. When the magnetic poles are the same in the width direction, a uniform magnetic field is formed, and the force acting on the ferromagnetic particles is also uniform, so that the separation efficiency of the ferromagnetic particles can be improved.

The magnetic sorting method of the present invention uses the magnetic sorting apparatus configured as described above to separate ferromagnetic particles from powder or granule containing ferromagnetic particles by magnetic force.

In the magnetic sorting apparatus and the magnetic sorting method of the present invention, a magnetic field change frequency f (Hz) indicating a change in the magnitude of a magnetic field acting on powder or granular material from a magnetic field applying means as defined in the following expression (1) is set to 170Hz or higher. More preferably, the magnetic field variation frequency F is 200Hz or higher,

F＝(x·P)/60…(1)

here, x: speed of rotation (rpm) of magnet roll

P: the number of magnetic poles provided in the circumferential direction of the magnet roller

For example, when the N pole (a), the S pole (b), and the N pole (c) are arranged in the circumferential direction, the pair of the N pole (a) and the S pole (b) is counted as 1 magnetic pole, and the pair of the S pole (b) and the N pole (c) is counted as 1 magnetic pole.

By setting the magnetic field change frequency f (Hz) of the magnetic field applying means to 170Hz or more, preferably 200Hz or more, it is possible to generate a high-speed change in the magnitude and direction of the magnetic field acting on the powder or granule, and to separate ferromagnetic particles contained in the powder or granule with high accuracy.

[ embodiment 1]

The apparatus of embodiment 1 includes: a first belt conveyor A for conveying the powder body a; and a second belt conveyor B which is positioned above the belt conveyor A and adsorbs and separates ferromagnetic particles from the powder/granular material a conveyed by the belt conveyor A by means of a magnet.

In the first belt conveyor a, 1 is a conveyor belt, 8 is a conveyor belt guide roller on the conveyor leading end portion 14 side, and 9 is a conveyor belt guide roller on the conveyor trailing end portion 10 side. The conveyor belt 1 is disposed between the belt guide rollers 8, 9, thereby constituting a belt conveyor a.

In the second belt conveyor B, 2 is a conveyor belt, 3 is a conveyor belt guide roller on the conveyor start end portion 11 side, 13 is a conveyor belt guide roller on the conveyor end portion 12 side, and the conveyor belt 2 is provided between the conveyor

belt guide rollers

3, 13, thereby constituting the belt conveyor B. In embodiment 1, the belt guide roller 3 is formed to have a larger diameter than the belt guide roller 13, and the rotation axis of the belt guide roller 13 is located above the rotation axis of the belt guide roller 3, whereby the upper surface of the belt 2 (the upper belt portion between the belt guide rollers 3 and 13) becomes substantially horizontal. However, the upper surface of the conveyor belt 2 may be lowered toward the conveyor belt guide roller 13.

A feeder 6 for feeding the powder/granular material a containing ferromagnetic particles onto the conveyor belt 1 is disposed at a position near the conveyor leading end 14 of the belt conveyor a.

The ferromagnetic particles adsorbed and held on the belt conveyor B side are discharged from the conveyor terminal end 12 after being conveyed by the belt conveyor B, and therefore the magnetized material recovery unit 7x is provided below the conveyor terminal end 12 of the belt conveyor B. Then, the nonmagnetic particles fall below the conveyor leading end portion 11 of the belt conveyor B, and the nonmagnetic material collection portion 7y is provided at this position.

In embodiment 1 of fig. 2, the conveyor start end portion 11 of the belt conveyor B is located at a position close to the upper side of the conveyor end portion 10 of the belt conveyor a. The belt guide rollers 8 and 9 of the belt conveyor a and the

belt guide rollers

3 and 13 of the belt conveyor B rotate in opposite directions to each other, and the belts 1 and 2 move in the same direction at the conveyor end 10 of the belt conveyor a and the conveyor start 11 of the belt conveyor B.

In the belt conveyor B, either one of the

belt guide rollers

3 and 13 may be a drive roller driven by a driving means such as a motor, but usually the belt guide roller 13 is a drive roller and the belt guide roller 3 is a non-drive roller. The belt guide roller 3 is internally formed of a hollow sleeve body, and is rotatably supported.

In embodiment 1, a magnet roller 4r is provided as magnetic field applying means including a plurality of magnets 5 inside the belt guide roller 3. The magnet roller 4r is configured to be rotatable independently of the belt guide roller 3.

In embodiment 1, as shown in fig. 3 described later, a plurality of magnets 5 are arranged at predetermined intervals in the circumferential direction and the width direction of the belt guide roller 3 on the magnet roller 4 r. The plurality of magnets 5 are arranged in such a manner that adjacent magnetic poles are alternately N-pole and S-pole in the roller circumferential direction 360 ° of the magnet roller 4 r. The plurality of magnets 5 are arranged so as to have the same magnetic pole in the width direction of the magnet roller 4 r.

The number of magnets 5 arranged in the roller circumferential direction, the interval between the magnets 5, and the like are not particularly limited, but if the number of magnets 5 is increased or the interval between the magnets 5 is decreased, the magnitude and direction of the magnetic field can be changed more quickly. In other words, even if the rotation speed of the magnet roller 4r is reduced, a high-speed magnetic field change can be obtained.

The strength of the magnetic field generated by the magnet 5 is not particularly limited, but it is generally preferable to select the magnet 5 so that the object comes to be about 0.01 to 0.5T at the conveyor belt portion in contact with the conveyor belt guide roller 3. If the magnetic field is too weak, the effect of the magnet roller 4r cannot be sufficiently obtained, while if the magnetic field is too strong, the attraction force acting on the ferromagnetic particles is too strong, and separation of the ferromagnetic particles may be inhibited.

In the apparatus according to embodiment 1, the magnetic field is switched to strong → weak → a.cndot.by the gap portion between the plurality of magnets 5 arranged at a predetermined interval and the adjacent magnets 5, and the effect of the assembly → dispersion → … is repeated for the ferromagnetic particles in the powder layer. The width of the gap between the adjacent magnets 5 in the roller circumferential direction is not particularly limited, but is preferably about 1 to 50mm in order to obtain the above-described effects.

Fig. 3 is a perspective view showing the structure of the conveyor belt guide roller of the magnetic sorting apparatus according to embodiment 1 of fig. 2. A magnet roller 4r having a plurality of magnets is disposed inside the belt guide roller 3. 40 denotes a roll shaft of the magnet roll 4 r. The roller shafts 30 at both ends of the belt guide roller 3 are externally attached to the roller shaft 40 of the magnet roller 4r disposed inside the belt guide roller 3, and are attached to the roller shaft 40 via bearings 15 (e.g., metal bearings, support bearings, etc.). However, the belt guide roller 3 and the magnet roller 4r can be independently rotated, and the roller shaft 30 and the roller shaft 40 can be formed in various manners.

The magnet roller 4r is a roller rotated by a unit such as a motor, and the rotation direction thereof may be either the same direction as the belt guide roller 3 or the opposite direction, but normally rotates in the opposite direction to the belt guide roller 3. The magnet roller 4r rotates at a higher speed than the belt guide roller 3.

In embodiment 1, it is preferable that the magnetic field change (the high-speed change in the strength and direction of the magnetic field) occurs at a speed as high as possible, and specifically, as described above, the magnetic field change frequency f (Hz) of the magnet roller 4r defined by the following expression (1) is preferably 170Hz or higher. More preferably, the magnetic field variation frequency is 200Hz or more,

F＝(x·P)/60…(1)

here, x: rotation speed (rpm) of magnet roller 4r

P: the number of magnetic poles provided to the magnet roller 4r (wherein the number of magnetic poles is 1 magnetic pole count as the N pole-S pole pair adjacent in the circumferential direction of the surface of the magnet roller 4r facing the powder particle body (a), for example, when the N pole (a), S pole (b), and N pole (c) are arranged in the circumferential direction, the N pole (a) and S pole (b) pair is counted as 1 magnetic pole, and the S pole (b) and N pole (c) pair is counted as 1 magnetic pole, for example, when a magnet (e.g., a magnet) of 12 poles (neodymium pole count of 1N pole-S pole pair) is arranged in the circumferential direction, when the rotation speed of the magnet roller 4r is 1000rpm, the magnetic field change frequency becomes 200 Hz., and a magnet of 24 poles (neodymium pole-S pole pair count is 1 magnetic pole) is arranged in the circumferential direction, and the magnetic field change frequency is similarly 200 Hz), the rotation speed of the magnet roller 4r may be 500 rpm.

Since the rotation speed of the magnet roller 4r has a mechanical upper limit or the effect of the magnetic field change is saturated even if the frequency is raised, the upper limit of the magnetic field change frequency is about 1000 Hz.

The size of the magnets 5 is not particularly limited, and may be any size as long as a predetermined number of magnets 5 can be arranged. In fig. 2, the magnetic poles of 1 magnet 5 are arranged so as to have different magnetic poles on the inner circumferential side and the outer circumferential side of the magnet roller 4r, but it is needless to say that the magnet 5 may be provided so that the different magnetic poles of 1 magnet 5 are arranged in the circumferential direction of the magnet roller 4 r. In this case, since the N-pole and S-pole are alternately provided, ferromagnetic particles can be efficiently separated. The N-pole and S-pole may be provided with the gap portion therebetween, and the N-pole and S-pole may be provided with the gap portion therebetween.

The gap between the magnets 5 may be filled with resin or the like, or a cover may be provided on the outer periphery of the magnet roller 4 r.

The rotation direction of the magnet roller 4r may be any of (i) a direction opposite to the traveling direction of the conveyor belt 2 (the rotation direction of the conveyor belt guide roller 3), and (ii) a direction identical to the traveling direction of the conveyor belt 2 (the rotation direction of the conveyor belt guide roller 3). The conveying force to move in the direction opposite to the rotating direction of the magnet roller 4r acts on the ferromagnetic particles by the magnetic field of the rotating magnet roller 4 r. In the case of (i) above, the conveying force to the ferromagnetic particles by the magnetic field is in the same direction as the frictional force between the conveyor 2 and the ferromagnetic particles. On the other hand, in the case of (ii) above, the conveying force and the frictional force are in opposite directions. However, in this case, since the frictional force is large, the ferromagnetic particles are transported in the traveling direction of the conveyor 2.

(i) In the case of (ii), the conveying force of the magnetic field to the ferromagnetic particles is opposite to the frictional force between the conveyor 2 and the ferromagnetic particles, and therefore the ferromagnetic particles may be retained on the conveyor 2, but the ferromagnetic particles can be separated more efficiently. On the other hand, in the case of (i), although the efficiency of separating ferromagnetic particles is slightly lower than that in the case of (ii), ferromagnetic particles do not remain on the conveyor 2, and there is an advantage that the particles can be smoothly conveyed.

The function and action of the magnetic sorting apparatus according to embodiment 1 and a magnetic sorting method using the apparatus will be described below.

In the magnetic sorting apparatus according to embodiment 1, the belt feeding speed of the conveyor belts 1 and 2 of the belt conveyor A, B may be set to a speed required for the treatment process. In the case of the magnetic sorting apparatus of fig. 2, the rotation speed of the magnet roller 4r is determined so that the change in the magnetic field becomes sufficiently high with respect to the belt feeding speed. In particular, the rotation speed of the magnet roller 4r is preferably set so as to satisfy the condition of the above-described expression (1).

In a state where the belt conveyor A, B is operating, a powder or granule a containing ferromagnetic particles is supplied from the supply device 6 onto the conveyor belt 1 while the belt conveyor a is moving, with a sufficient thickness, and the powder or granule a is conveyed to the conveyor terminal end 10. The upper surface of the powder/granular material a conveyed by the conveyor 1 is in contact with the lower surface of the conveyor start end 11 of the belt conveyor B in the vicinity of the conveyor end 10, and the powder/granular material a is inserted between the conveyor end 10 of the belt conveyor a and the conveyor start end 11 of the belt conveyor B. At this time, the magnetic field of the magnetic field applying unit 4 of the belt conveyor B is applied to the powder or granular material a.

Here, in the case of the magnetic sorting apparatus of fig. 2, the ferromagnetic particles in the powder and granular bodies a adhere to the lower surface side of the belt conveyor B so as to embrace the nonmagnetic particles by the magnetic force of the magnet roller 4r as the magnetic field applying unit 4, and are conveyed by the conveyor belt 2. The ferromagnetic particles in the powder/granular body a are acted on by the magnetic field of the magnet 5 provided in the magnet roller 4r, but the strength of the magnetic field is instantaneously switched to strong → weak → … by the rotation of the magnet roller 4 r. The effect of collective → dispersion → · appears repeatedly for ferromagnetic particles in the powder layer.

In addition, when the magnetic field applying means is constituted by the magnet roller 4r independently rotating from the belt guide roller 3 as in the embodiment of fig. 2, the following actions are exerted: (1) mechanically generating a high-speed magnetic field change by rotating the magnet roller 4 r; (2) supplying the powder or granule a into the varying magnetic field in a sufficient layer thickness; (3) the magnetic field change eliminates the entrainment and holding of the ferromagnetic particles to the nonmagnetic particles, and at the same time, the ferromagnetic particles move toward the magnet roller 4r side, and the nonmagnetic particles are removed toward the side away from the magnet roller 4 r; (4) the nonmagnetic particles fall down by gravity at the conveyor starting end portion 11 of the belt conveyor B, and the ferromagnetic particles are conveyed in a state of being adsorbed and held by the belt conveyor B and discharged from the conveyor terminal end portion 12 of the belt conveyor B; on the other hand, as shown in fig. 2, even if the powder/granular body a supplied to the conveyor 1 is sufficiently thickened, the ferromagnetic particles can be efficiently separated magnetically. That is, the ferromagnetic particles can be magnetically sorted efficiently and quickly from the powder/granular body a.

In the apparatus according to embodiment 1 of fig. 2, since the magnet roller 4r rotates, the intensity and direction of the magnetic field are likely to be changed 100 times or more while the powder or granule a is being conveyed along the belt guide roller 3 of the belt conveyor B. Further, since the behavior of the ferromagnetic particles in the magnetic field changes depending on the target powder particle a, the rotation speed of the magnet roller 4r can be adjusted to obtain appropriate performance.

In the conventional apparatus shown in fig. 8, although the separation effect of the ferromagnetic particles of the powder and granular particles a is produced due to the change in the strength and direction of the magnetic field corresponding to the number of magnets, the number of times of change of the magnetic field is limited (several to ten times) due to the fixed magnets, and the separation effect of the ferromagnetic particles is small. In contrast, in the apparatus according to embodiment 1, since the magnet roller 4r rotates, the magnetic field is easily changed 100 times or more while the powder or granule is conveyed along the conveyor 2.

Since the magnetic sorting apparatus according to embodiment 1 can perform magnetic sorting of ferromagnetic particles from the powder and granular bodies a efficiently as described above, in the magnetic sorting of the powder and granular bodies a using the apparatus, as shown in fig. 2, the powder and granular bodies are preferably supplied from the supply device 6 onto the conveyor belt 1 of the belt conveyor a in a layer thickness larger than the diameter of the smallest particles included in the powder and granular bodies a and in a layer thickness on which the magnetic force sufficiently acts. Specifically, the thickness of the powder or granule may be 20 to 30 mm.

The powder or granule to be subjected to magnetic separation in the apparatus of embodiment 1 is not particularly limited, but examples thereof include slag such as iron making slag, iron ore tailings (tailing ore), and the like. Wherein the method is particularly suitable for magnetic separation of slag.

In recovering the iron component from the slag, first, the iron making slag is atomized. When the micronization is insufficient, the recovery rate of the iron component cannot be improved. In the iron making and steel making process in which the iron making slag is generated, there are various processes, and thus the generated slag is also various. The grain size of slag after atomization is determined by slag, but depending on the type of iron contained, it is often necessary to atomize the slag to about several tens of μm to 1 mm. The micronization method is usually pulverization. As the coarse pulverization, after pulverization by a jaw crusher (jaw crusher) or a hammer crusher (hammer crusher), pulverization is carried out by using a ball mill (ball mill), rod mill (rod mill), jet mill (jet mill), pin mill (pinmill), impact mill (impact mill) or the like for further pulverization. As another method, there is a method of heating to about 1000 to 1300 ℃ and then slowly cooling.

The magnetic separation by the magnetic separation apparatus of the present invention is performed on the granulated slag. The present invention enables efficient separation and recovery of iron components from slag.

In embodiment 1 shown in fig. 2, the magnet 5 is disposed so that the magnetic poles of the portions facing the powder and granular bodies a are the same in the width direction of the belt guide roller 3 (magnet roller 4 r). When the same magnetic poles are arranged in the width direction, a uniform magnetic field is formed, and the force acting on the ferromagnetic particles becomes uniform, but when the magnets 5 are arranged so as to have different magnetic poles in the width direction, the magnetic field becomes nonuniform, and a portion where the ferromagnetic particles are not separated is locally generated, and the separation efficiency is lowered.

The member around the rotating magnet roller is affected by the eddy current effect generated by the changing magnetic field, and the metal member is heated by the eddy current even if it is a nonmagnetic object. Therefore, the belt 2 and the belt guide roller 3 of the belt conveyor B according to the present embodiment are made of a nonmetal such as resin or ceramic.

The apparatus according to embodiment 1 causes the magnetic field of the magnet roller 4r provided inside the belt guide roller 3 on the conveyor start end 11 side of the belt conveyor B to act on the powder particles a (powder particle layer) conveyed by the belt conveyor a, and attracts the ferromagnetic particles in the powder particles a to move to the lower surface side of the belt conveyor B, thereby separating the ferromagnetic particles. Therefore, the distance between the conveyor terminal end portion 10 of the belt conveyor a and the conveyor starting end portion 11 of the belt conveyor B may be set to a size at which the magnetic force of the magnet roller 4r sufficiently acts on the ferromagnetic particles in the powder/granular material a, but it is generally preferable to be a size at which the upper surface of the layer of the powder/granular material a conveyed by the conveyor belt 1 of the belt conveyor a can be brought into contact with the conveyor starting end portion 11 of the belt conveyor B, that is, a size at which the powder/granular material layer can be inserted between the conveyor terminal end portion 10 of the belt conveyor a and the conveyor starting end portion 11 of the belt conveyor B.

Next, modification 1 of embodiment 1 of the present invention will be described. Fig. 4 is a diagram showing a magnetic sorting apparatus according to variation 1 of embodiment 1 of the present invention.

Modification 1 is different from fig. 2 in the positional relationship between the belt conveyor a and the belt conveyor B. That is, the conveyor start end portion 11 of the belt conveyor B is located above and close to the conveyor end portion 10 of the belt conveyor a, and the belt guide rollers 8 and 9 of the belt conveyor a and the

belt guide rollers

3 and 13 of the belt conveyor B rotate in the same direction. The conveyor belts 1 and 2 move in opposite directions at the conveyor end 10 of the belt conveyor a and the conveyor start 11 of the belt conveyor B.

It is needless to say that this arrangement also enables the ferromagnetic particles to be separated. The configuration is substantially the same as that of embodiment 1 in fig. 2 and 3 except for the positional relationship between the belt conveyors a and B, and therefore, the description thereof is omitted.

Next, modification 2 of embodiment 1 of the present invention will be described. Fig. 5 is an explanatory view showing a modification 2 of the magnetic sorting apparatus according to embodiment 1 of the present invention and a magnetic sorting method using the apparatus.

In modification 2 of embodiment 1, the belt guide roller 3 is formed of a hollow sleeve body and is rotatably supported. A magnetic field applying unit 4 is provided inside the belt guide roller 3, and the magnetic field applying unit 4 includes a plurality of magnets 5 arranged at predetermined intervals along the roller circumferential direction.

The magnetic field applying means 4 of modification 2 does not rotate unlike the magnet roller 4r of embodiment 1. In other words, the magnet 5 of the magnetic field applying unit 4 is a fixed magnet that is provided independently from the belt guide roller 3 and does not rotate. As shown in fig. 3, the magnets 5 of the magnetic field applying unit 4 are arranged such that adjacent magnetic poles in the roller circumferential direction are different from each other, and such that adjacent magnetic poles in the roller width direction are the same.

As shown in fig. 5, in modification 2 of embodiment 1, the range of the roller circumferential direction in which the magnets 5 are arranged is at least about 180 ° (half circumference of the belt guide roller 3) from the lower end position of the belt guide roller 3 (the position facing the conveyor terminal end 10 of the belt conveyor a) to the top position of the belt guide roller 3. As in modification 2, if the magnet 5 is fixed so as not to rotate, the range in which the magnet 5 is provided can be reduced.

The magnetic sorting apparatus of modification 2 attracts ferromagnetic particles in the powder/granular material a by the magnetic field applying unit 4 including the fixed magnet 5, and the powder/granular material a (or a part thereof) is attached to (held by) the lower surface side of the belt conveyor B so that the ferromagnetic particles embrace the nonmagnetic particles, and is conveyed by the conveyor belt 2. In this apparatus, although the effect is smaller than that of the magnet roller 4r of fig. 2, the ferromagnetic particles in the powder and granular body a are subjected to the magnetic force of the magnet 5 provided in the magnetic field applying means 4, and the magnetic field is switched to strong → weak → strong → … during the conveyance by the conveyor belt 2, so that the assembly → dispersion → … is repeated for the ferromagnetic particles in the powder and granular body a, and the same effect as that in the case of embodiment 1 of fig. 2 can be obtained. However, since the magnetic field does not change at a high speed as in the magnet roller 4r of fig. 2, the magnetic sorting performance and the processing speed are lower than those of embodiment 1 of fig. 2.

The magnetic separator of modification 2 has the following operational effects: (i) since the basic mode is adopted in which the magnetic field generated by the magnetic field applying unit 4 provided in the second belt conveyor B acts on the powder/granular material a discharged from the first belt conveyor a from above, the ferromagnetic material contained in the powder/granular material a is adsorbed, and the ferromagnetic material is moved to the belt conveyor B side, the entrainment and entrainment of the nonmagnetic material particles by the ferromagnetic material particles can be reduced as compared with the conventional device, and (ii) the entrainment and entrainment of the nonmagnetic material particles by the ferromagnetic material particles are eliminated by the change in the magnetic field by the magnetic field applying unit 4.

Fig. 6 is a perspective view showing a structure of a conveyor belt guide roller in modification 3 of the magnetic sorting apparatus according to embodiment 1 of fig. 2. As shown in fig. 6, in modification 3 of embodiment 1, a plurality of magnets 5 provided in the magnet roller 4r are provided along the circumferential direction of the belt guide roller 3 (magnet roller 4r), and only 1 magnet is provided in the width direction of the belt guide roller 3 (magnet roller 4 r). The magnets 5 are arranged along the circumferential direction so that magnetic poles facing the powder and granular particles a alternate. The magnet 5 may be configured as described above.

[ embodiment 2]

Fig. 7 is an explanatory view showing an embodiment of the magnetic sorting apparatus according to embodiment 2 and a magnetic sorting method using the same.

The magnetic sorting apparatus according to embodiment 2 is a belt conveyor type magnetic sorting apparatus as in embodiment 1. The magnetic sorting apparatus according to embodiment 2 supplies the powder/granular body a including ferromagnetic particles from the supply device onto the conveyor 201, and when the powder/granular body a is discharged from the conveyor terminal part 2010, the ferromagnetic particles are attracted by a magnetic force and separated from the nonmagnetic particles.

In fig. 7, 201 denotes a conveyor belt, 202 denotes a conveyor belt guide roller on the conveyor terminal end 2010 side, and 208 denotes a conveyor belt guide roller on the conveyor leading end 2011 side. The conveyor belt 201 is disposed between the conveyor

belt guide rollers

202, 208, thereby constituting a belt conveyor. The belt conveyor rotates the conveyor belt 201 by driving means such as a motor via the belt guide roller 208. The belt guide roller 202 is a non-driving roller, and is constituted by a hollow sleeve body.

A magnet roller 203 is disposed inside the belt guide roller 202. The magnet roller 203 has substantially the same structure as that shown in fig. 3. Specifically, the magnet roller 203 includes a plurality of magnets 205 arranged at predetermined intervals in the circumferential direction and the width direction thereof, and the magnetic poles of the magnets 205 adjacent to each other in the roller circumferential direction have different magnetic poles (N pole, S pole). That is, the magnets 205 are arranged such that N poles and S poles alternate in the roller circumferential direction. The plurality of magnets 205 are arranged so as to have the same magnetic pole in the width direction of the roller.

The magnet roller 203 is a roller rotated by a motor or the like, and rotates in the direction opposite to the belt guide roller 202. As will be described later, the magnet roller 203 rotates at a higher speed than the belt guide roller 202.

The member around the rotating magnet roller is affected by the eddy current effect generated by the changing magnetic field, and the metal member is heated by the eddy current even if it is a nonmagnetic material. Therefore, the conveyor belt 201 and the conveyor belt guide roller 202 are made of nonmetal such as resin and ceramic.

The magnets 205 are arranged so as to have the same magnetic pole in the width direction of the magnet roller 203. When the magnetic poles are the same in the width direction, a uniform magnetic field is formed, and the force acting on the ferromagnetic particles becomes uniform, but when the magnets 205 are arranged with magnetic poles different in the width direction, the magnetic field becomes nonuniform, and a portion where the ferromagnetic particles are not separated is locally generated, and the separation efficiency is lowered. However, the magnet 205 may be arranged by one magnet in the width direction as shown in fig. 6, or may be arranged by appropriately dividing as shown in fig. 3.

Although the number, arrangement interval, and the like of the magnets 205 provided along the outer periphery of the magnet roller 203 are not particularly limited, a high-speed magnetic field change can be obtained even if the rotation speed is slow when the number of the magnets 205 is increased or the arrangement interval is decreased.

In embodiment 2, similarly to embodiment 1, it is preferable that the change in the strength and direction of the magnetic field is generated at a speed as high as possible, and specifically, the frequency f (Hz) of the change in the magnetic field of the magnet roller 203 defined by the following expression (1) is preferably 170Hz or higher. More preferably, the magnetic field variation frequency is 200Hz or more,

F＝(x·P)/60…(1)

here, x: speed of rotation (rpm) of magnet roll

P: for example, when the N pole (a), the S pole (b), and the N pole (c) are arranged in the circumferential direction, the pair of the N pole (a) and the S pole (b) is counted as 1 magnetic pole, and the pair of the S pole (b) and the N pole (c) is counted as 1 magnetic pole.

For example, when a magnet (e.g., a neodymium magnet) having 12 poles (the N pole-S pole pair is counted as 1 magnetic pole) is arranged in the circumferential direction, the magnetic field change frequency is 200Hz when the rotation speed of the magnet roller 203 is 1000 rpm. When 24-pole magnets (the number of N-pole-S-pole pairs is 1 magnetic pole) are arranged in the circumferential direction and the magnetic field variation frequency is set to 200Hz in the same manner, the rotation speed of the magnet roller 203 may be 500 rpm.

The upper limit of the magnetic field change frequency is about 1000Hz because of the mechanical upper limit of the rotation speed of the magnet roller 203 and the saturation of the effect of the magnetic field change even if the frequency is increased.

The size of the magnet 205 is not particularly limited, and may be any size as long as a predetermined number of magnets can be arranged. The strength of the magnetic field generated by the magnet 205 is not particularly limited, but it is generally preferable to select the magnet 205 so that the belt portion in contact with the belt guide roller 202 becomes approximately 0.01 to 0.5T according to the object. If the magnetic field is too weak, the effect of the magnet roller 203 cannot be sufficiently obtained. On the other hand, if the magnetic field is too strong, the attractive force acting on the ferromagnetic particles is too strong, and separation of the ferromagnetic particles by the above-described principle (fig. 1(a) to (D)) may be inhibited.

The basic function of the apparatus according to embodiment 2 for separating ferromagnetic particles is also as described with reference to fig. 1.

The gap portion between the plurality of magnets 205 arranged at a predetermined interval and the adjacent magnet 205 has a characteristic in that the strength of the magnetic field is instantaneously switched to strong → weak → … when the magnet roller 203 rotates, and the effect of aggregation → dispersion → … is repeatedly obtained for the ferromagnetic particles in the powder layer. The width of the gap between the magnets 205 adjacent to each other in the roller circumferential direction is not particularly limited, but is usually appropriate to be about 1 to 50mm in order to appropriately generate a state in which ferromagnetic particles in the powder layer are released from the magnetic field and to avoid a state in which the magnetic field is weakened to be excessively long.

A partition plate 206 is disposed below (directly below) the conveyor belt guide roller 202 in the conveyor belt width direction, and a gap S for allowing ferromagnetic particles to pass therethrough is provided between an upper end portion of the partition plate 206 and the conveyor belt 201 (a conveyor belt portion in which the movement direction of the conveyor belt guide roller 202 is reversed). The separator 206 is provided in such a manner that the falling region of the nonmagnetic particles is adjacent to the falling region of the ferromagnetic particles, and therefore, the two particles are prevented from being mixed during the falling.

In addition, a magnetized material recovery unit 207x and a non-magnetized material recovery unit 207y are provided at positions across the partition plate 206 in the belt moving direction. That is, the magnetized material recovery unit 207x is provided at a position (falling region of ferromagnetic particles) on the conveyor start end 2011 side and the non-magnetized material recovery unit 207y is provided at a position (falling region of non-magnetic particles) on the conveyor end portion 2010 side with the partition plate 206 interposed therebetween.

The function and action of the magnetic sorting apparatus according to embodiment 2 and a magnetic sorting method using the apparatus will be described below.

In the magnetic sorting apparatus according to embodiment 2, the belt feed speed of the conveyor belt 201 (the rotational speed of the conveyor belt guide rollers 202 and 208) may be any speed necessary for the treatment process. The rotation speed of the magnet roller 203 is determined so that the change in the magnetic field becomes sufficiently high with respect to the belt feed speed. In particular, the rotation speed of the magnet roller 203 is preferably set so as to satisfy the condition of the above-described expression (1).

The powder or granule a containing ferromagnetic particles is supplied from the supply device 204 onto the conveyor 201 in operation to a sufficient thickness, and conveyed to the conveyor terminal 2010 (the positions of the conveyor guide roller 202 and the magnet roller 203). When the powder or granule a on the conveyor 201 is discharged from the conveyor terminal 2010, the ferromagnetic particles in the powder or granule a are acted on by the magnetic field of the magnet 205 provided in the magnet roller 203, but the strength of the magnetic field is instantaneously switched to strong → weak → … by the rotation of the magnet roller 203, and the effect of aggregation → dispersion → … can be repeatedly obtained for the ferromagnetic particles in the powder or granule a.

In the conveyor terminal part 2010, the powder/granular material a is conveyed along the arc of the conveyor guide roller 202 in accordance with the movement of the conveyor 201, but in the region from 1/4 rotation to 1/2 rotation, the nonmagnetic particles fall freely by gravity. On the other hand, since the ferromagnetic particles are made fine, the mass thereof is reduced, and the strength of the magnetic field is sufficiently large, the ferromagnetic particles are directly attracted to the magnet even if they fall from the conveyor belt 201. The ferromagnetic particles are then transported in the traveling direction of the conveyor 201, and fall off the magnetic field region while rotating 1/2 or more. The nonmagnetic particles that have fallen first are collected by the nonmagnetic material collection unit 207y, and the ferromagnetic particles that have fallen are collected by the magnetized material collection unit 207 x. At this time, the separator 206 prevents the nonmagnetic particles and the ferromagnetic particles from being mixed. The position of the partition plate 206 may be adjusted according to the feeding speed of the conveyor 201 or the dropping behavior of the powder or granular body a.

In the magnetic sorting apparatus according to embodiment 2, the magnet 205 is disposed so as to have the same magnetic pole as the powder or granular particles a in the width direction of the belt guide roller 202 (magnet roller 203). This produces an effect of forming a uniform magnetic field in the width direction and also making the magnetic force acting on the ferromagnetic particles uniform.

In addition, in the magnetic sorting apparatus according to embodiment 2, the following actions are taken: (i) a magnetic field change at a high speed is mechanically generated by rotating the magnet roller 203; (ii) supplying the powder/granular material a in a sufficient layer thickness in the changing magnetic field; (iii) the magnetic field variation eliminates the entanglement and holding of the nonmagnetic particles generated by the ferromagnetic particles, and at the same time, the ferromagnetic particles move toward the magnet roller 203, and the nonmagnetic particles are removed toward the side away from the magnet roller 203; (iv) at the lower part of the belt guide roller 202, the nonmagnetic particles fall down due to gravity, and the ferromagnetic particles are carried in a state of being adsorbed and held to the belt 201 side and fall down at a place where the influence of the magnetic field disappears; as a result, as shown in fig. 7, even if the layer thickness of the powder/granular body a supplied to the conveyor 201 is sufficiently increased, the ferromagnetic particles can be efficiently sorted magnetically. That is, the ferromagnetic particles can be magnetically sorted efficiently and quickly from the powder/granular body a.

In the conventional apparatus as shown in fig. 8, although the separation effect of the ferromagnetic particles of the powder and granular particles a is produced due to the change in the strength and direction of the magnetic field corresponding to the number of magnets, the number of changes of the magnetic field is limited (several to ten times) due to the fixed magnets, and the separation effect of the ferromagnetic particles is small. In contrast, in embodiment 2, since the magnet roller 203 rotates, the magnetic field is easily changed 100 times or more while the powder or granule a is conveyed along the conveyor guide roller 202.

Since the stirring behavior changes depending on the target powder or granule a, the rotation speed of the magnet roller 203 can be adjusted to obtain appropriate performance.

Since the magnetic sorting apparatus according to embodiment 2 can perform magnetic sorting of ferromagnetic particles from the powder or granular body a efficiently as described above, in the magnetic sorting of the powder or granular body a using the apparatus, it is preferable to supply the powder or granular body a from the supply device 204 onto the conveyor 201 in a layer thickness larger than the diameter of the smallest particle contained in the powder or granular body a and in a layer thickness on which a magnetic field sufficiently acts, as shown in fig. 7. Specifically, the thickness of the powder or granule may be 20 to 30 mm.

Further, the gap S between the upper end of the partition plate 206 and the conveyor 201 is preferably set to be smaller than the thickness of the powder or granule a supplied from the supply device 204 onto the conveyor 201. The partition plate 206 is provided for the purpose of preventing ferromagnetic particles and nonmagnetic particles falling from the conveyor belt 201 at the conveyor terminal end 2010 from mixing, but it is preferable that the upper end of the partition plate 206 is as close as possible to the conveyor belt 201. Specifically, if the gap S is made smaller than the layer thickness of the powder or granular body a, the ferromagnetic particles and the nonmagnetic particles can be prevented from being mixed.

The powder or granule to be subjected to magnetic separation in the apparatus of embodiment 2 is not particularly limited, but examples thereof include slag such as iron making slag, iron ore tailings, and the like. Among these, magnetic separation of slag is also particularly preferred.

In recovering the iron component from the slag, first, the iron making slag is atomized. If the micronization is insufficient, the recovery rate of the iron component cannot be improved. The iron making and steel making process for producing iron making slag includes various steps, and thus the produced slag is also various. The grain size of slag after atomization is determined by slag, but depending on the type of iron contained, it is often necessary to atomize the slag to about several tens of μm to 1 mm. The method of micronization is usually pulverization. As the coarse pulverization, after the pulverization by a jaw crusher or a hammer crusher, the pulverization is carried out by using a ball mill, a rod mill, a jet mill, a pin mill, an impact mill or the like for further pulverization. As another method, there is a method of heating to about 1000 to 1300 ℃ and then slowly cooling. The magnetic separation by the magnetic separation apparatus of the present invention is performed on the granulated slag. This enables efficient separation and recovery of the iron component from the slag, and improves the productivity of the slag treatment line.

Although an eddy current type sorting apparatus having a structure similar in appearance is known as a sorting apparatus for ferromagnetic substances, since the principle of sorting metal particles is different and particles are scattered by repulsive force, a mechanism for adjusting the position of a recovery casing in accordance with the size of the metal particles to be recovered is required, and a space is also required. In contrast, in the present invention, since the position adjustment of the recovery case is not required, a complicated mechanism for this purpose is not required.

The present invention is not limited to the sorting apparatus and the sorting method according to embodiments 1 and 2 described above, and various design changes may be made. The magnetic separation method of embodiments 1 and 2 may be used as a method for producing an iron source by which an iron source is produced from a by-product of an iron-making process.

Example 1

The magnetic separation of the steelmaking slag was performed by using the magnetic separation apparatus according to embodiment 1 of the present invention shown in fig. 2.

After the crushed steel making slag was screened at 400 μm, the slag having passed through the screen mesh was used as the powder or granule to be magnetically sorted. The iron concentration of the granules was 54 mass%. The thickness of the powder/granular material supply layer on the belt 1 of the belt conveyor A was 7 mm. The belt guide roller 3 of the belt conveyor B had an outer diameter of 300mm, the number of magnetic poles of the magnet roller 4r was 12 poles (wherein, the N-pole-S-pole pair was 1 magnetic pole), the feed speed of the belts 1, 2 of the belt conveyor A, B was 0.5m/S, the rotation speed of the belt guide roller 3 was 31.9rpm, and the magnetic field strength at the belt portion in contact with the belt guide roller 3 was 0.2T. In order to examine the effect of the rotation speed of the magnet roller 4r of the belt conveyor B, the rotation speed of the magnet roller 4r was set to 500rpm (magnetic field change frequency F: 100Hz), 850rpm (magnetic field change frequency F: 170Hz), or 1200rpm (magnetic field change frequency F: 240 Hz).

For comparison, the powder and granular material of the same steel-making slag was magnetically sorted at a feed speed of 0.5m/s using a conventionally generally used cylindrical magnetic separator A (magnetic field intensity on the cylindrical surface: 0.16T) and a pulley magnetic separator B (magnetic field intensity at the conveyor belt portion in contact with the conveyor belt guide roller: 0.2T).

In each of the above examples, the iron concentration of the magnetization recovered material and the iron recovery rate from the slag were investigated. The results are shown in Table 1.

First, the magnetization recovered material of comparative example 1 using the cylindrical magnetic separator a had a low iron concentration because of the inclusion of the non-iron component, and also had a low iron recovery rate because of the escape of iron to the non-magnetization side. In comparative example 2 using the pulley magnetic separator B, the iron recovery rate was certainly good because substantially the entire amount of the powder and granular material was entangled, but the iron concentration of the key magnetization-recovered material was almost unchanged from that of the powder and granular material before magnetic separation. In contrast, in the present example, when the magnetic field change frequency of the magnet roller 4r is set to 170Hz or more, the iron concentration of the magnetization-recovered material and the iron recovery rate of the slag can both be high, and when the magnetic field change frequency of the magnet roller 4r is set to 200Hz or more, the iron concentration of the magnetization-recovered material and the iron recovery rate of the slag can both be high.

[ Table 1]

Example 2

Magnetic separation of the steelmaking slag was performed by using the magnetic separation apparatus of embodiment 2 as shown in FIG. 7.

After the crushed steel making slag was screened at 400 μm, the slag having passed through the screen mesh was used as the powder or granule to be magnetically sorted. The iron concentration of the granules was 54 mass%. The thickness of the layer for supplying the powder/granular material to the conveyor 201 was 7 mm. The outer diameter of the belt guide roller 202 was 300mm, the number of magnetic poles of the magnet roller 203 was 12 poles (wherein, the N pole-S pole pair was 1 magnetic pole), the feed speed of the belt 201 was 0.5m/S, the rotation speed of the belt guide roller 202 was 31.9rpm, and the magnetic field strength at the belt portion in contact with the belt guide roller 202 was 0.2T. In order to examine the effect of the rotation speed of the magnet roller 203 of the belt conveyor, the rotation speed of the magnet roller 203 was set to 500rpm (magnetic field change frequency F: 100Hz), 850rpm (magnetic field change frequency F: 170Hz), or 1200rpm (magnetic field change frequency F: 240 Hz).

For comparison, the same steel-making slag powder was subjected to magnetic separation at a feed speed of 0.5m/s using a conventionally generally used cylindrical magnetic separator A (magnetic field strength on the cylindrical surface: 0.16T) and a pulley magnetic separator B (magnetic field strength on the conveyor belt portion in contact with the conveyor belt guide roller 202: 0.2T).

In each of the above examples, the iron concentration of the magnetization recovered material and the iron recovery rate from the slag were investigated. The results are shown in Table 2.

First, the magnetization recovered material of comparative example 1 using the cylindrical magnetic separator a had a low iron concentration because of the inclusion of the non-iron component, and also had a low iron recovery rate because of the escape of iron to the non-magnetization side. In comparative example 2 using the pulley magnetic separator B, the recovery rate was certainly good because substantially the entire amount of the powder and granular material was entangled, but the iron concentration of the key magnetization-recovered material was almost unchanged from that of the powder and granular material before magnetic separation. In contrast, in the present example, when the magnetic field variation frequency of the magnet roller 203 is 170Hz or more, the iron concentration of the magnetization-recovered material and the iron recovery rate of the slag can both be high, and when the magnetic field variation frequency of the magnet roller 203 is 200Hz or more, the iron concentration of the magnetization-recovered material and the iron recovery rate of the slag can both be high.

[ Table 2]

Description of the reference symbols

1. 2, 20 conveyor belt

3. 8, 9, 13 conveyor belt guide roller

4 magnetic field applying unit

4r magnet roller

5 magnetic pole and magnet

6 supply device

7x magnetized substance recovery part

7y non-magnetized substance recovery part

10. 12 conveyor terminal section

11. 14 conveyor start end

15 bearing

21 conveyor belt guide roller

22 magnet

23 feeding device

24x magnetized substance recovery part

24y non-magnetized substance recovery part

25 division plate

26 vibration feeder

27 conveyor terminal end

30. 40 roll shaft

A. B belt conveyor

a powder and granular material

201 conveyor belt

202 conveyor belt guide roller

203 magnet roller

204 supply device

205 magnetic pole and magnet

206 divider plate

207x magnetized substance collecting part

207y non-magnetized substance collecting section

208 conveyor belt guide roller

Terminal part of 2010 conveyor

2011 beginning end of conveyer

S gap

Claims

1. A magnetic sorting device has:

F＝(x·P)/60…(1)

in this case, the amount of the solvent to be used,

x: speed of rotation (rpm) of magnet roll

2. The magnetic sorting apparatus of claim 1, wherein,

3. The magnetic sorting apparatus of claim 1, wherein,

4. The magnetic sorting apparatus of claim 2 or 3, wherein,

5. The magnetic sorting apparatus of claim 2 or 3, wherein,

6. A magnetic sorting method, wherein,

use of the magnetic sorting device according to any one of claims 1 to 5,

7. A method for producing an iron source from a by-product of an iron-making process by using the magnetic separation apparatus or the magnetic separation method according to any one of claims 1 to 6.