JPH05123605A - Method for recovering ground metal contained in slag - Google Patents

Abstract

PURPOSE:To efficiently recover ground metal by changing both the magnetic force of a rotary type magnetic separator and the circumferential speed of a drum in accordance with the grain size of slag, ground metal content and the feed rate of slag in the case of recovering ground metal from slag by the rotary type magnetic separator. CONSTITUTION:A stationary magnet 2 extending in a nearly semicircle is provided on the inner circumferential face of a drum 1 rotated in the circumferential direction. A raw material is supplied on the circumferential face of the drum 1 through a feeder 3 and separated into the magnetized material and the nonmagnetized material. Herein, magnetic force of a magnetic separator and the circumferential speed of the drum 1 are changed in accordance with the grain size of slag 5, ground metal content and the feed rate of slag. Thereby ground metal is efficiently separated and removed from slag without receiving the influence of the feed rate and the grain size of slag. Further, the ground metal content of the magnetized material is arbitrarily controlled and the deposit on the magnet is efficiently and effectively utilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of recovering ingots from slag generated in the iron and steel industry to effectively utilize the slag.

[0002]

2. Description of the Related Art In recent years, effective use of slag has been attempted from the viewpoint of resource saving and the like, and its use destinations are, for example, roadbed materials and cement raw materials. In this case, if the metal remains in the slag, the rust of the metal becomes a problem in the roadbed material, and the metal in the cement raw material causes the abrasion of the crushing mill, so remove the metal as much as possible from the slag, It is necessary to use slag with a small amount of metal. On the other hand, the metal ingot taken out from the slag is used as a sintering raw material or the like. That is, slag containing a large amount of metal can be used as a sintering raw material,
Even with the slag slag generated under the converter, the metal content is only about 20% and cannot be used as a sintering raw material as it is. Therefore, the slag having a high metal content, which is selected from the slag, is used as a sintering raw material.

A magnetic separator has been conventionally used for collecting the metal in the slag (Japanese Patent Laid-Open No. 54-88894).
Japanese Unexamined Patent Application Publication No. Sho. The rotating drum type magnetic separator, as shown in FIG. 1, includes a drum 1 that rotates in the circumferential direction,
It has a fixed magnet 2 which is opposed to its inner peripheral surface for approximately half a circumference, and separates a raw material 5 supplied onto the peripheral surface of the drum 1 through a feeder 3 into a magnetic material 6 and a non-magnetic material 7. Then, in the bullion recovery using the rotating drum type magnetic separator, the bullion in the slag is adsorbed on the peripheral surface of the drum 1,
By being conveyed backward in the rotation direction, a slag having a high metal content rate that can be used as a sintering raw material is obtained as the magnetic substance 6, while a metal content rate that can be used as a roadbed material or a cement raw material is obtained. The low slag is obtained as the non-magnetic substance 7.

[0004]

However, in this conventional seed metal recovery method, when the amount of slag supplied is increased, the recovery rate of metal is reduced and it becomes difficult to obtain slag with a small amount of metal. Therefore, the supply amount of slag was limited, and the processing capacity was low. Further, depending on the particle size of the slag, the raw material is splashed on the outer peripheral surface of the drum, which causes a problem of a decrease in processing ability due to a decrease in magnetic separation efficiency. Further, the metal in the slag is not limited to the metal alone, as shown in FIG.
Although mixed with slag in various states, in the conventional method, only those exceeding a specified metal content rate are uniformly recovered, and it is not possible to control the metal content rate of the recovered material. It was impossible. Therefore, no matter whether the non-magnetic material is used or the magnetic material is used, it is only a slag with a specific property.
It could not be effectively used effectively.

An object of the present invention is to provide a method of recovering metal in slag, which enables efficient recovery of metal from a wide variety of slags by controlling the content ratio thereof.

[0006]

Means for Solving the Problems In order to achieve the above-mentioned object, the present inventor has a recovery rate and a metal content rate of recovered metal when recovering metal in slag with a rotary drum type magnetic separator. Various investigations were made on various factors affecting the above. As a result, the causes of various conventional problems are that the magnetic force and peripheral speed of the magnetic separator are fixed, and there is a specific drum peripheral speed with a high recovery rate for a specific slag supply amount. It was found that the recovery rate changes depending on the particle size of the supplied slag, and that the metal content rate of the recovered magnetic deposit is affected by the drum peripheral velocity and the magnetic force.

The present invention has been made on the basis of the above-mentioned findings, and when recovering metal from a slag adjusted to a predetermined particle size by a rotating drum type magnetic separator, the particle size of the slag, metal content and A gist of a method of recovering metal in slag is characterized in that the magnetic force of the magnetic separator and the drum peripheral speed are changed according to the supply amount.

[0008]

When the peripheral speed of the drum is low with respect to the amount of slag supplied to the rotary drum type magnetic separator, a thick slag layer is formed on the peripheral surface of the drum 1 as shown in FIG. 1 (A). I can. Then, in the surface layer of the slag layer, the magnetic field is weak,
It becomes difficult to collect the metal, and a large amount of metal is mixed with the non-magnetic substance 7 to deteriorate the recovery rate. On the contrary, when the peripheral speed of the drum 1 is high, as shown in FIG. 1 (B), although a thick slag layer cannot be formed, it is repelled by centrifugal force before the metal is magnetically selected, and the metal is also recovered. The rate drops. However, when the drum 1 is rotated at an appropriate peripheral speed determined by the supply amount of slag, the thick slag layer and slag scattering are suppressed, and a high recovery rate is secured.

At this time, if the particle size of the supplied slag is small, the slag is easily splashed. Therefore, in order to improve the recovery rate of the metal, it is necessary to adjust the peripheral speed of the drum depending on the particle size of the slag.

Regarding the metal content of the recovered material, the magnetic force of the magnetic separator is weakened and the peripheral speed of the drum is increased, the higher the ratio is. On the contrary, when it is desired to decrease the metal content, the magnetic force is reduced. Make it stronger and slow the peripheral speed of the drum. This is because the stronger the magnetic force, the less the amount of metal in the magnetic substance enters and the content of the metal decreases, and when the peripheral speed of the drum is increased, the amount of metal in the metal will be blown away by centrifugal force. , Because it increases the metal content rate. Therefore, by adjusting the magnetic force of the magnetic separator and the drum peripheral speed, the metal content of the recovered material can be arbitrarily controlled.

[0011]

EXAMPLES Examples of the present invention will be described below.

First, a case will be described in which the ingot is removed as much as possible from a slag having a relatively low ingot content of 5% or less to make effective use of the slag.

The converter slag with various grain sizes adjusted was passed through a rotary drum type magnetic separator with a variable peripheral speed and a variable magnetic force to recover the metal. FIG. 3 shows the recovery rate by particle size when the drum peripheral speed was changed with a slag supply amount of 100 T / Hr (constant) and a magnetic force of 1600 gauss (constant). The recovery rate is represented by the metal content of non-magnetic particles, and the lower the recovery rate, the higher the recovery rate. Drum diameter is 624 mm, drum width is 1950 mm
Is.

As can be seen from FIG. 3, the grain size is 0-5 mm.
In the case of, the drum peripheral speed is 50 m / min, and the highest recovery rate is obtained. When the particle size is 0 to 13 mm, the optimum peripheral speed is 80 m / min. Moreover, 100 m / min becomes the optimal in 0-25 mm. Therefore, as the particle diameter becomes larger, the higher the drum peripheral speed, the higher the recovery rate is maintained.

The optimum peripheral velocity when the magnetic flux is fixed at 1600 gauss and the supply amount of slag having a particle size of 0 to 13 mm is changed is as shown in FIG. As a result, even if the slag supply amount is increased, it is possible to efficiently collect the ingots by increasing the peripheral speed.

Incidentally, when the drum peripheral speed is fixed at 50 m / min, the slag supply amount is 100 as shown in FIG.
At the time of T / Hr, the slag with a particle size of 0 to 13 mm and 0 to 25 mm is different from the optimum peripheral speed, so the metal recovery rate is low. In the case where the drum peripheral speed is fixed at 50 m / min, in order to optimize the metal recovery rate of slag having a particle size of 0 to 13 mm, the slag supply amount is set to 74 T / Hr from FIG.
Need to lower. That is, if the drum peripheral speed is made variable, there is an effect of improving productivity and metal collecting efficiency.

For reference, the slag supply amount is 100T.
FIG. 5 shows the results when the magnetic force was increased under the conditions of / Hr and slag particle size of 0 to 13 mm. Whether the drum peripheral speed is 50 m / min or 80 m / min, the recovery rate increases as the magnetic force increases, and strengthening the magnetic force is also effective for improving the recovery rate.

By increasing the metal recovery rate in this way, slag with a small amount of metal can be efficiently obtained. Therefore,
Slag can be effectively and effectively used as a roadbed material, cement raw material, etc. with high commercial value.

Next, a case will be described in which the ingot is recovered from the slag having a relatively high ingot content by further increasing the ingot content.

Slopping slag generated under the converter has a metal content of about 20%, but a metal raw material content of 50% or more is required as a sintering raw material. It cannot be used. Therefore, slag having a metal content of 21.4% before magnetic separation was magnetically selected at various drum peripheral speeds.
The drum diameter was 624 mm, which was the same as that in the above-mentioned embodiment, and the magnetic force was 1200 gauss, which was weaker than that in the above-mentioned embodiment. The magnetic separation result is shown in FIG.

As shown in FIG. 6, when the magnetic force is 1200 gauss, the metal content is 50% or more at the drum peripheral velocity of 150 m / min or more. In addition, classification efficiency is 1 drum peripheral speed
The maximum value is obtained at 80 m / min, and the metal content rate of the magnetic deposit is 55% and the metal recovery rate is 87%. Therefore, the magnetic force is 1200 gauss and the drum peripheral speed is 180 m /
By adjusting the amount, the slag is efficiently recovered as a sintering raw material.

FIG. 7 shows the results when slag having a metal content of 30.7% before magnetic separation was used. The higher the metal content before magnetic separation, the higher the quality of the metal.

FIG. 8 shows the relationship between the magnetic force and the metal content of the magnetic substance to be recovered when the drum peripheral speed is kept constant at 180 m / min. It is also possible to adjust the content ratio of the recovered metal by adjusting the magnetic force according to the purpose of use of the recovered metal. That is, the magnetic force may be weakened when recovering a metal having a high metal content, and the magnetic force may be adjusted strongly when recovering a metal having a low metal content.

[0024]

As is apparent from the above description, the method of recovering the metal in slag according to the present invention makes the magnetic force of the magnetic separator and the drum peripheral speed variable so that the influence of the slag supply amount and the particle size can be reduced. Efficiently separates and removes the metal from the slag without receiving it, and enables effective use of non-magnetic substances without waste. Further, the metal content of the magnetic substance can be arbitrarily controlled, and the magnetic substance can be effectively used without waste.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an influence of a slag supply amount on magnetic separation.

FIG. 2 is a schematic diagram showing a contained state of metal.

FIG. 3 is a chart showing the influence of the drum peripheral speed on the metal recovery rate for each grain size.

FIG. 4 is a chart showing the optimum drum peripheral speed when the slag supply amount is changed.

FIG. 5 is a chart showing the influence of magnetic force on the metal recovery rate.

FIG. 6 is a chart showing the influence of the drum peripheral speed on the metal content rate of the recovered material together with the recovery rate and the classification efficiency.

FIG. 7 is a chart showing the influence on the metal content of the recovered material when the metal content of slag is changed.

FIG. 8 is a chart showing the same effect when the magnetic force is changed.

[Explanation of symbols]

 1 drum 2 magnet 5 raw material 6 magnetic material 7 non-magnetic material

Claims (1)

[Claims] 1. When collecting metal from a slag adjusted to a predetermined grain size by a rotating drum type magnetic separator, the magnetic force of the magnetic separator according to the grain size of the slag, the metal content and the supply amount. And a method of collecting metal in slag, characterized by changing the drum peripheral speed.