JP6015335B2 - Magnetic sorting method and magnetic sorting equipment - Google Patents

Description

  The present invention relates to a technique for magnetically separating (separating) ferromagnetic particles from a granular material containing ferromagnetic particles, and is suitable, for example, for separating iron from slag, which is a byproduct of an iron making process. The present invention relates to a magnetic sorting method and magnetic sorting equipment.

  In the hot metal preliminary treatment and converter decarburization process, slag (steel slag) is generated as a by-product of the treatment. This slag is a reaction and product of calcium additives added to remove impurities and unnecessary elements in hot metal and molten steel. In addition to the removed elemental compounds, slag contains a lot of iron. It is. Most of the forms of slag are massive, but the size (size before aggregation) is about several hundred μm even if it is large.

  Since slag contains a lot of iron, it is separated and recovered for recycling. Usually, iron recovered from slag is mixed with scrap in a converter process to produce a cold iron source, and thus iron is separated and recovered in the following steps. First, the slag is passed through a sieve called grits, and a large (several hundred mm) iron block contained in the slag is removed (shape selection). The small lump that has passed through the grease-type sieve has the iron and slag components fixed, so it is roughly crushed with a Hanmark lasher or rod mill to a size of several hundreds of μm to several tens of mm and separated into single pieces (separation of slag and iron) ). Thereafter, iron is separated by magnetic separation. As the magnetic force sorting device, devices such as a hanging type, a drum type, and a pulley type are generally used.

Moreover, it heats in order to isolate | separate iron, and after crushing after controlling the cooling time, it may crush. Depending on the cooling time, the iron ingot can be crushed and separated without being crushed, or can be pulverized to about several tens of μm.
Needless to say, if the pulverization progresses by any of the methods, the separation of the simple substance progresses.
Generally, in order to improve the separation concentration of iron, it is necessary to proceed to the single body separation, so that the particle size is reduced by repeating mechanical crushing. Alternatively, the diameter may be reduced by heat treatment.

On the other hand, when the particle size of the powder is reduced, an aggregation phenomenon of particles occurs due to the influence of electrostatic force and intermolecular force. In general, this agglomeration phenomenon is observed in particles having a size of 30 to 50 μm or less under dry conditions, and the particles behave as a large lump even if they are separated.
Usually, a drum type magnetic separator or a pulley type magnetic separator is used to separate the ferromagnetic material from the powder. However, in order to separate the ferromagnetic material at a high concentration, the amount of powder supplied to the device is reduced. It is desirable to adjust the supply layer thickness to a single layer supply in which only one particle or at most about two particles overlap in the layer thickness direction. However, when the agglomeration phenomenon occurs, the non-magnetic particles are adsorbed on the ferromagnetic particles, and a large amount of non-magnetic particles are mixed on the magnetized recovered material side.
In order to avoid agglomeration, a wet process as shown in Patent Document 1 is generally applied, but there is a problem that the waste liquid treatment cost becomes enormous.

Japanese Patent Laid-Open No. 10-130041

  Therefore, an object of the present invention is to solve the above-described problems of the prior art, and to use a dry magnetic separator when magnetically selecting ferromagnetic particles from a granular material containing ferromagnetic particles. It is an object of the present invention to provide a magnetic force sorting method and a magnetic force sorting facility that can separate ferromagnetic particles at a high concentration.

The gist of the present invention for solving the above problems is as follows.
[1] A method of supplying a magnetic particle (a) containing ferromagnetic particles to a magnetic separator (2) and magnetically selecting ferromagnetic particles from the granular material (a) in the magnetic separator (2) Because
The granular material (a) is passed through a sieve (3) having an opening size equal to or larger than the target maximum particle size of the granular material (a) and less than twice the target maximum particle size. Is directly received by the conveying surface of the supply device (1), conveyed and supplied to the magnetic separator (2).
[2] The magnetic force selection method according to [1], wherein the supply device (1) is one of a vibration feeder, a belt conveyor, and an inclined chute.
[3] The magnetic force selection method according to [1] or [2], wherein the magnetic force separator (2) is a drum magnetic separator or a pulley magnetic separator.
[4] The magnetic force selection method according to any one of [1] to [3], wherein the sieve (3) has an opening size of 50 μm or less.

[5] Equipment for supplying powder particles (a) containing ferromagnetic particles to the magnetic separator (2) and magnetically selecting ferromagnetic particles from the powder (a) in the magnetic separator (2) Because
A sieve (3) having a mesh size of not less than the target maximum particle size of the granular material (a) and less than twice the target maximum particle size, and the granular material (a) under the sieve (3) are transported. A magnetic separator having a supply device (1) that directly receives and conveys it to the magnetic separator (2).
[6] The magnetic field separation facility according to [5], wherein the supply device (1) is any one of a vibration feeder, a belt conveyor, and an inclined chute.
[7] The magnetic field separation facility according to [5] or [6], wherein the magnetic field separator (2) is a drum magnetic field separator or a pulley magnetic field separator.
[8] The magnetic force sorting facility according to any one of [5] to [7], wherein the sieve (3) has an opening size of 50 μm or less.

  According to the present invention, the agglomeration is physically released by sieving the granular material, and the granular material under the sieving is directly received by the supply device and directly supplied to the magnetic separator. Even if the particle size is small (for example, 50 μm or less), the ferromagnetic particles can be separated at a high concentration using a dry magnetic separator.

Drawing which shows the flow of the magnetic sorting method of the present invention Drawing which shows one embodiment of the present invention, and shows the flow in the case of separating iron from steelmaking slag from the stage of pretreatment In FIG. 2, the explanatory diagram showing the equipment configuration of the part surrounded by the chain line and the implementation status of magnetic separation Drawing which shows other embodiments of the present invention, and shows the flow in the case of separating iron from steelmaking slag from the stage of pretreatment. In FIG. 4, the explanatory diagram showing the equipment configuration of the part surrounded by the chain line and the implementation status of magnetic separation Explanatory drawing which shows the installation condition in other embodiment of this invention, and the implementation condition of magnetic selection Explanatory drawing showing the state of implementation of conventional magnetic separator and magnetic separator

  Taking the case where the object of magnetic separation is iron-manufactured slag as an example, in the recovery of iron from the slag, first, the slag is atomized and the iron is separated as a single substance. If the atomization is insufficient, the separation concentration of iron in the subsequent process is not improved. There are various types of steelmaking and steelmaking processes that generate steelmaking slag, and the generated slag is also diverse. Although the atomization particle size is determined according to slag, it is often necessary to atomize to about several tens of μm to 1 mm depending on the form of iron contained. As a method of atomization, pulverization is common. After coarsely pulverizing with a jaw crusher or a Hanmark crusher, further pulverization is performed 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 also a method of gradually cooling after heating to about 1000 to 1300 ° C.

Next, separation of iron and slag components is carried out, and agglomeration occurs when the particle size is less than 30-50 μm. In general, a magnetic separator (dry type) using magnetic force is used for iron separation, but in the case of such a small particle size, the separation efficiency of iron is extremely deteriorated due to the aggregation phenomenon as shown in FIG. FIG. 7 shows a conventional method for supplying powder (slag) stored in a hopper to a drum type magnetic separator using a vibration feeder. Nonmagnetic particles (slag component) are mixed in the magnetized matter collecting part side, and ferromagnetic particles (iron) are mixed in the nonmagnetized matter collecting part side.
In order to improve this aggregation phenomenon, a wet magnetic separator is generally used. Since water can be used as a dispersion medium, the separation performance is dramatically improved as compared with the dry type, but the waste liquid treatment cost becomes enormous, and this is a big problem when it is necessary to treat in large quantities like iron slag.

Therefore, in the present invention, the agglomeration is physically released by sieving the granular material, and the granular material under the sieving is directly received by the conveying surface of the supply device and directly conveyed to the magnetic separator. To do. Thereby, even if it is a granular material with a small particle diameter (for example, 50 micrometers or less), a sufficiently effective separation performance can be exhibited with a dry magnetic separator.
That is, as shown in the flow of FIG. 1, the powder a including ferromagnetic particles is supplied to the magnetic separator 2, and when the magnetic particles are magnetically selected from the granular a in the magnetic separator 2. The granular material a is passed through a sieve 3 having an opening size that is equal to or larger than the target maximum particle size of the granular material a and less than twice the target maximum particle size. Is received directly, conveyed and supplied to the magnetic separator 2.

As the supply device 1, a vibration feeder, a belt conveyor, an inclined chute or the like is usually used, but is not limited thereto. Moreover, the conveyance surface of the supply apparatus 1 is a site | part which mounts and conveys the granular material a, and is a vibration surface in a vibration feeder, a belt conveyance surface in a belt conveyor, and a chute surface in an inclination chute. In addition, as the magnetic separator 2, a drum magnetic separator, a pulley magnetic separator, or the like, which is a dry magnetic separator, is usually used, but is not limited thereto. Moreover, as the sieve 3, although a vibration sieve etc. are normally used, it is not limited to this.
Here, the target maximum particle size of the granular material a is a pulverized particle size set by a pulverizer.

If the granular material a is passed through the sieve 3 having an opening size of not less than the target maximum particle size of the granular material a and less than twice the target maximum particle size, the aggregation of most of the particles can be released. it can.
The granular material a that has passed through the sieve 3 for releasing the aggregation is in a state where the aggregation is released, for example, the conveying surface of the feeding device 1, for example, the vibrating surface of the vibration feeder, the belt conveying surface of the belt conveyor, and the chute chute It falls directly on the surface. And since the supply apparatus 1 (vibration feeder, belt conveyor, inclined chute, etc.) transports the granular material a that has been unagglomerated and supplies it to the magnetic separator 2, the granular material a having almost no aggregation is obtained. Magnetic sorting is possible.

  The opening size of the sieve 3 is set to be equal to or larger than the target maximum particle size of the granular material a and less than twice the target maximum particle size. Moreover, it is preferable to set it as the target maximum particle size of the granular material a especially, and aggregation of the granular material a can be cancelled | released more effectively by this. Moreover, since the granular material a with a particle size of 50 micrometers or less is easy to produce aggregation especially, it is preferable that the opening dimension of the sieve 3 is 50 micrometers or less.

  The magnetic separation equipment of the present invention is an equipment for supplying magnetic particles a containing ferromagnetic particles to the magnetic separation device 2, and magnetic separation of the ferromagnetic particles from the granular material a in the magnetic separation device 2, The sieve 3 whose mesh size is equal to or larger than the target maximum particle size of the granular material a and less than twice the target maximum particle size and the granular material a under the sieve of the sieve 3 are directly received by the conveying surface, and are conveyed Thus, a supply device 1 for supplying the magnetic sorter 2 is provided. The details of the supply device 1, the magnetic separator 2 and the sieve 3 constituting this facility are as described above.

  FIG. 2 shows one embodiment of the present invention, and shows the flow in the case of separating iron from steelmaking slag from the stage of pretreatment. In FIG. 2, a part surrounded by a chain line is a flow part corresponding to the present invention, and FIG. 3 shows an equipment configuration of this part and an implementation state of magnetic selection. Magnetic separation is performed according to the particle size while repeating crushing and sieving. There are various types of steelmaking slag depending on the process to be generated, and the particle size of the iron contained is also various, but in many cases, iron having a particle size of 10 to 50 μm is dispersed in the slag. In order to separate such iron, it is necessary to grind it to a particle size of 50 μm or less using a rod mill or a ball mill. In accordance with the present invention, the powder (target maximum particle size 50 μm) pulverized to a particle size of 50 μm is charged into a sieve (sieve 3) having an opening size of 50 μm. At this time, the sieve having a particle diameter of more than 50 μm is returned to the ball mill / rod mill. The sieve is dropped directly onto the vibration surface (conveyance surface) of the vibration feeder (supply device 1). Since each particle passes through the 50 μm sieve, the aggregation is released with a diameter of at least 50 μm, and the particles fall on the vibration surface of the vibration feeder in this state and are conveyed in the horizontal direction by the conveying action of the vibration feeder. Then, the drum type magnetic separator (magnetic separator 2) is charged and magnetically selected.

FIG. 4 shows another embodiment of the present invention, and shows the flow in the case of separating iron from steelmaking slag from the stage of pretreatment. In FIG. 4, the part enclosed by the chain line is a flow part corresponding to the present invention, and the equipment configuration of this part and the state of implementation of magnetic separation are shown in FIG. In this embodiment, a belt conveyor is used as the supply device 1, and a pulley type magnetic separator is used as the magnetic separator 2. Further, a sieve having an opening size of 30 μm is used as the sieve 3. In accordance with the present invention, the powder (target maximum particle size 30 μm) pulverized to a particle size of 30 μm is charged into a sieve (sieving 3) having an opening size of 30 μm. At this time, the sieve having a particle diameter of more than 30 μm is returned to the ball mill / rod mill. The sieve is dropped directly onto the belt conveyor surface of the belt conveyor (supply device 1). Since each particle passes through a 30 μm sieve, the agglomeration is released with a diameter of at least 30 μm. In this state, the particles are transported in the horizontal direction by a belt conveyor and loaded in a pulley type magnetic separator (magnetic separator 2). And magnetically sorted.

In general, the slag after being pulverized by a ball mill or a rod mill is temporarily stored in a hopper or the like. In such a case, the influence of aggregation is particularly great. FIG. 6 shows a preferred embodiment (equipment configuration and magnetic sorting state) suitable for such a case.
In this embodiment, powder (target maximum particle size 50 μm) pulverized to 50 μm is primarily stored in the hopper. From this hopper, the powder is charged into a sieve (sieve 3) having an opening size of 50 μm through a vibration feeder, and the sieve is dropped directly onto the vibration surface (conveying surface) of the vibration feeder (supply device 1). The powder is transported in the horizontal direction by the transporting action of the vibration feeder, loaded into the drum type magnetic separator (magnetic separator 2), and magnetically sorted.

Steelmaking slag (target maximum particle size: 50 μm, iron concentration: 54 mass%) pulverized to a particle size of 50 μm or less by pretreatment was magnetically selected by the method of the present invention (method of FIG. 6) and the conventional method (method of FIG. 7). . In the method of the present invention, the opening size of the sieve 3 is set to 50 μm which is the target maximum particle size.
Table 1 shows the results of examining the iron concentration and the iron recovery rate from the slag of the magnetically collected material of each example.
In the conventional method, almost all of the charged powder was carried to the magnetized recovered material side by aggregation. For this reason, the iron concentration on the magnetized recovered material side is almost unchanged from the original powder. On the other hand, in the method of the present invention, high values are obtained for both the iron concentration of the magnetically collected material and the iron recovery rate of the slag.

1 supply device 2 magnetic separator 3 sieve a granular material

Claims (6)

A powder (a) containing ferromagnetic particles obtained by pulverizing an object of magnetic selection with a pulverizer is supplied to the magnetic separator (2), and the granular particles are supplied to the magnetic separator (2). A method for magnetically selecting ferromagnetic particles from the body (a),
The granular material (a) has an opening size of 50 μm or less and the target maximum particle size of the granular material (a) (where the target maximum particle size is a pulverized particle size set by the pulverizer) The same applies to the above, and the powder (a) under the sieve is directly received by the conveying surface of the feeding device (1) through the sieve (3) less than twice the target maximum particle diameter, and this is conveyed. And supplying to a magnetic separator (2).   The magnetic separation method according to claim 1, wherein the supply device (1) is one of a vibration feeder, a belt conveyor, and an inclined chute.   3. The magnetic separation method according to claim 1, wherein the magnetic separator (2) is a drum type magnetic separator or a pulley type magnetic separator. A powder (a) containing ferromagnetic particles obtained by pulverizing an object of magnetic selection with a pulverizer is supplied to the magnetic separator (2), and the granular particles are supplied to the magnetic separator (2). A facility for magnetically selecting ferromagnetic particles from the body (a),
The opening size is 50 μm or less, and the target maximum particle size of the powder (a) (provided that the target maximum particle size is a pulverized particle size set by the pulverizer; the same applies hereinafter). The screen (3) less than twice the maximum particle size and the granular material (a) under the screen (3) are directly received by the transport surface, transported and supplied to the magnetic separator (2). Magnetic separation equipment characterized by having a supply device (1) to perform. The magnetic separator according to claim 4 , wherein the supply device (1) is one of a vibration feeder, a belt conveyor, and an inclined chute. The magnetic separator according to claim 4 or 5 , wherein the magnetic separator (2) is a drum type magnetic separator or a pulley type magnetic separator.

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