KR101363922B1 - Stabilizing method of slag - Google Patents

Abstract

The present invention relates to a slag stabilization method for stabilizing barium (Ba) contained in the thallinic slag of ferro-manganese so as not to react with water or various acids, comprising: preparing a slag; Injecting the slag into a cooling device rotatably formed; Cooling the slag to stabilize Ba in the slag into the composite oxide phase; and controlling elution of Ba in the slag into the composite oxide phase by controlling the cooling rate of the slag, thereby preventing elution of Ba when the slag is buried. Can be.

Description

Stabilizing method of slag

The present invention relates to a slag stabilization method, and more particularly, to a slag stabilization method for stabilizing barium (Ba) contained in the delineated slag of ferro-manganese so as not to react with water or various acids.

Ferro-manganese used for steelmaking ferroalloy is high carbon ([C] <7.5% or less, based on KS standard KSD3712), heavy coal ([C] <2.0% or less, based on KS standard KSD3712) and low coal ([C] <1.0% or less, based on KS standard KSD3712).

A general process for producing such ferro manganese is prepared by charging manganese ore and reducing agent coke and slag forming agent (Flux) in the electric furnace, and reducing the manganese ore in the form of oxide using carbon of the coke. As such, ferro-manganese produced in an electric furnace using coke is obtained in the form of high-carbon ferro-manganese in which carbon is saturated in a product due to coke as a reducing agent.

A method of preparing bicarbonate or low carbon ferro manganese by removing carbon from the high carbon ferro manganese has been proposed. For example, a method of preparing low carbon ferro manganese by melting and reducing Mn ore in an electric furnace using SiMn, or melting A method of producing low-carbon ferro-manganese is used as decarburization is performed by blowing oxygen into high-carbon ferro-manganese.

Phosphorus (P) content of commonly used ferro manganese is currently high as 0.4% or less as defined by KS and JIS standards, and phosphorus (P) content is also 0.1 to 0.2 even in ferro manganese which is used for steelmaking. It is relatively high in%.

However, in addition to carbon, phosphorus has a great influence on the properties of the steel depending on its content in the steelmaking process. In the case of carbon, high carbon ferro manganese or medium / low carbon ferro manganese can be selectively used depending on the carbon content of the steel produced. However, in the case of phosphorus (P), high carbon, heavy carbon, and low carbon ferro manganese have the same phosphorus content. Therefore, even if the type of ferroalloy was changed, there was no method of avoiding the effect of phosphorus (P) in ferro manganese.

Phosphorus (P) is present as an impurity in steel and deteriorates the quality of steel products, such as causing high temperature brittleness, and thus, except for special cases, efforts are made to lower the content of phosphorus (P) in molten steel. Therefore, in the case of using ferro-manganese ferroalloy, an increase in phosphorus (P) concentration in molten steel by the ferroalloy should be taken into account, and thus, ferro-manganese cannot be used.

Thus, a method for producing low phosphorus ferro manganese with low phosphorus (P) has been proposed.

The method for preparing low ferro-manganese includes beneficiation by operating only high-quality manganese ores with low phosphorus (P) content, and slag or low phosphorus (P) ore produced in the high-carbon ferro-manganese manufacturing process. Al, Ca, etc.) has been proposed, but has had problems such as rising price of high-quality manganese ore and inadequate mass production.

Thus, a method for producing low ferro-manganese has been proposed by subjecting directly to high-carbon ferro-manganese produced in an electric furnace.

This method can be largely divided into reduced thallin and thaloxide. Reduction Tallinn phosphide phosphorus (P) of the ferro-manganese and the method of removing in the form of a _{(Ca 3 P 2, Mg 3} P 2 , etc.), oxidation Tallinn cargo phosphate phosphorus (P) of ferro manganese (Ba ₃ ( PO ₄ ) _2, etc.).

Among them, in the case of oxidative delineation, it is known that BaCO ₃ , BaO, BaF ₂ , BaCl ₂ , CaO, CaF ₂ , Na ₂ CO ₃ , Li ₂ CO _3, or the like is used as the dephosphorizing agent. Here, since the Ca-based dephosphorizer has low dephosphorization efficiency, and Na and Li-based dephosphorizer have high vapor pressure, the ablation phenomenon occurs, and therefore, a Ba-based dephosphorizer such as BaCO ₃ or BaO is mainly used for dephosphorization of ferro manganese.

Therefore, when deferring ferro manganese using Ba-based dephosphorization agents such as BaCO ₃ or BaO, Ba is inevitably contained in slag generated after dephosphorization treatment. However, since Ba is a water-soluble substance, when the slag is disposed of in landfill, Ba is eluted from rainwater or groundwater, thereby contaminating the environment. Therefore, development of a slag treatment method capable of stabilizing Ba contained in the slag of ferro-manganese so as not to elute.

KR 1036317 B1 KR 0750373 B1 KR 0778551 B1

The present invention provides a slag stabilization method that can suppress the elution of Ba from the slag by controlling the cooling rate of the slag.

The present invention provides a slag stabilization method capable of quenching slag to stabilize Ba in the slag onto the composite oxide phase.

The present invention provides a slag stabilization method that can prevent environmental pollution that may occur due to elution of Ba.

Slag stabilization method according to an embodiment of the present invention, the process of providing a slag; Injecting the slag into a cooling device rotatably formed; And cooling the slag to stabilize Ba in the slag into the composite oxide phase. In this case, the slag may be produced in the process of de-lining ferro manganese using a dephosphorization agent containing Ba.

When the slag temperature in the process of stabilizing the slag is 1000 ℃ or more, it is preferable to cool the slag at a rate of 400 ℃ / min or more.

The slag may be cooled by supplying water to the inside of the cooling device to control the temperature of the cooling device, and the cooling of the slag may be performed by adjusting the rotation speed of the cooling device.

Ba in the slag is stabilized in the Ba-Mn composite oxide phase, the Ba-Mn composite oxide phase may be at least one of 2BaOMnO, BaOMnO and BaO2MnO.

After the slag is stabilized, an additional treatment step may be performed to recover Ba remaining in the slag.

The further treatment step comprises the steps of immersing the slag in a solvent to elute Ba in the slag; Separating Ba and the eluted solution from the residue; Injecting an additive into the solution to produce Ba by-products; And recovering the by-products.

The slag may be crushed before the slag is immersed in a solvent to facilitate the elution of Ba contained in the slag.

The additive may contain sulfate ion (SO ₄ ^{2 −} ) or carbon dioxide (CO ₂ ), and the by-product generated may be BaSO ₄ or BaCO ₃ .

The slag stabilization method according to the embodiment of the present invention can suppress the elution of water-soluble Ba that can occur during the disposal process such as tallin slag landfill, thereby suppressing the occurrence of environmental pollution. In other words, by controlling the cooling rate of the slag to stabilize the elutable Ba in the slag to the composite oxide phase, it is possible to suppress the elution of Ba when the slag is embedded. In addition, it is possible to stabilize Ba in the slag generated after the delineation process by a simple method of controlling the cooling rate without using expensive raw materials such as sulfuric acid, thereby reducing the cost required to stabilize the slag.

1 is a view showing a slag cooling apparatus applied to the slag stabilization method according to the present invention.
2 is a flow chart showing a process of stabilizing slag according to an embodiment of the present invention.
Figure 3 is a flow chart showing a process of further processing the stabilized slag according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know.

The slag stabilization method according to the present invention is a method for stabilizing Ba contained in various kinds of slag, wherein ferro manganese is BaO, BaCO ₃ A method of stabilizing Ba contained in slag generated after dephosphorization using a Ba-based substance such as dephosphorization agent into a complex oxide phase which does not elute in water and does not react with other acids will be described.

1 is a view showing a slag cooling apparatus applied to the slag stabilization method according to the present invention.

First, the slag cooling apparatus for stabilizing the slag will be described as follows.

Referring to Figure 1, the slag cooling device is provided in the lower portion of the ladle 10, the container 20 for receiving the liquid slag 12, the drive means 30 for rotating the container 20, and the container 20 Cooling water supply means 40 for supplying the cooling water 42 to the. In this case, the container 20 includes an inner container 22 containing the liquid slag 12 and an outer container 24 provided at a distance from the inner container 22 at a predetermined distance from an outer side of the inner container 22. It is formed in a structure, and is installed to be rotatable at a predetermined angle. In addition, the coolant 42 is supplied to a space formed between the inner container 22 and the outer container 24 so as not to directly contact the slag 12 introduced into the inner container 22. This is because when the coolant 42 is in direct contact with the hot slag 12, the coolant 42 may rapidly evaporate and explode, or fine dust may scatter and contaminate the surroundings. Cooling water supply means 40 and the vessel 20 is connected through a pipe or the like, the cooling water 42 discharged from the vessel 20 is discharged to the outside and then cooled and the vessel 20 again through the cooling water supply means 40 It may also consist of a circulation system supplied to

Such a slag cooling device is preferably provided under the ladle 10 so that the slag 12 in the ladle 10 can be directly injected into the container 20 of the cooling device after the Tallinn operation.

2 is a flowchart showing a process of stabilizing slag according to an embodiment of the present invention.

Referring to FIG. 2, the slag stabilization process includes preparing a slag 12 (S110), cooling the slag 12, and putting the slag 12 into a container 20 of a cooling device (S112) and cooling the slag 12. And stabilizing Ba in the slag 12 into the composite oxide phase (S114).

The slag 12 is a by-product generated after the dephosphorization operation of ferro manganese, and the slag contains Ba in the slag using a Ba-based material as the dephosphorization agent. The slag 12 is fed directly into the vessel 20 of the chiller in the ladle 10. At this time, the vessel 20 is rotated by the driving means 30, the cooling water 42 is supplied to the space between the inner vessel 22 and the outer vessel 24. The inner vessel 22 is cooled by the coolant 42 supplied between the inner vessel 22 and the outer vessel 24, and the liquid slag 12 of the inner vessel 22 is rotated as the vessel 20 rotates. It is solidified by being attached to the inner wall and cooling. At this time, since the container 20 rotates in a state inclined at a predetermined angle, it is possible to suppress a phenomenon in which the cooled and solidified slag 12 is physically crushed and aggregated while falling. The slag 12 thus cooled is discharged to the outside of the container 20.

In the process of cooling the slag 12, the cooling water 42 may be continuously supplied between the inner container 22 and the outer container 24 to control the cooling rate of the slag 12.

Conventional Tallinn slag is a BaO (BaCO ₃ ) -MnO-based slag is gradually cooled at room temperature when solidified, Ba in the slag is separated into a complex oxide phase of a large amount of BaO and MnO and Ba-Mn. BaO is believed to be a major cause of Ba elution. Therefore, in the embodiment of the present invention by quenching the high-temperature slag completed the Tallinn operation to stabilize Ba in the slag to the composite oxide phase to suppress the elution of Ba from the slag.

Cooling of the slag may be performed through a method of controlling the temperature of the vessel 20 into which the slag 12 is introduced. Temperature control of the vessel 20 may be performed through the supply rate of the cooling water 42 supplied to the space between the inner vessel 22 and the outer vessel 24. That is, when the coolant 42 is supplied to the vessel 20 at a high speed, the time for which the coolant 42 stays in the vessel 20 is shortened, and thus the vessel 20 is cooled quickly. It can be cooled quickly.

The initial temperature of the slag 12 to be introduced into the vessel 20 is a high temperature state of about 1400 ℃ usually, as described above when rotating while supplying the cooling water 42 into the vessel 20 slag 12 in the vessel 20 ) Cools quickly. For example, when the initial temperature of the slag 12 put into the container 20 is 1000 degreeC or more, it is quenched at the speed | rate at least 400 degree-C / min or more. At this time, when the temperature of the slag 12 is high, for example, 1000 ° C. or more, the cooling rate is relatively faster than that when the cooling rate is 1000 ° C. or less.

In addition, it may be performed by controlling the rotational speed of the vessel (20). As the rotation speed of the vessel 20 increases, the number of times of contact between the slag 12 and the vessel 20 may increase, thereby improving the cooling rate of the slag 12.

As the slag is quenched as described above, Ba in the slag is stabilized into a complex oxide phase such as 2BaOMnO, BaOMnO, BaO 2 MnO, and thus, even when the slag is buried as it is, it hardly elutes because the Ba remains in the composite oxide phase.

Since trace amounts of Ba can be eluted from the stabilized slag, further processing to recover Ba remaining in the slag can be performed. Further processing can be performed in the following manner.

3 is a flow chart showing a process of further processing the stabilized slag according to an embodiment of the present invention.

Referring to FIG. 3, the further treatment may include a step of injecting slag into a solvent (S202), a step of eluting Ba contained in the slag (S204), and a solution from which the Ba is eluted and a residue (slag) to be separated. Process (S206), and the step of adding an additive to the solution (S210) and separating the residual solution and the precipitate and recovering the precipitate (S212). At this time, in order to facilitate the elution of Ba prior to adding the slag to the solution may be included (S200) for crushing the slag.

The slag that has undergone the rapid cooling process as described above is crushed to have an average particle size of 0.5 mm or less (S200).

Next, the crushed slag is added to a solution such as water (S202), and soaked for 6 to 48 hours to elute Ba contained in the slag (S204).

Subsequently, the solution from which the Ba is eluted and the slag (residue) are separated (S206).

Subsequently, the residue is treated through landfill and the like (S208), and the separated solution is added with an additive capable of stabilizing by reacting with Ba (S210). Additive is a sulfate ion (SO ₄ ^{2 -)} is an air or gas containing sulfuric acid solution or carbon dioxide (CO ₂₎ containing may be used. For example, when a sulfuric acid solution is added to a solution in which Ba is eluted, Ba reacts with sulfate ions (SO ₄ ^{2 −} ) to precipitate as BaSO ₄ is produced in a stabilized form. In addition, when the air or gas containing carbon dioxide is blown into the solution in which Ba is eluted, Ba reacts with carbonate ions (CO ₃ ^2- ) to precipitate as BaCO ₃ is produced in a stabilized form.

Next, the precipitate and the remaining solution are separated (S212), and the precipitate is recovered (S213). The residual solution may be discharged by neutralization treatment or recycled into treated water required for steelmaking (S214).

Slag stabilization experiments were carried out using slag produced after the dephosphorization of ferro manganese was completed using a dephosphorization agent mainly containing BaCO ₃ .

The prepared slag was crushed, and the crushed slag was put in a container and melted in an experiment furnace. At this time, the target temperature of the experiment furnace was adjusted to be 1400 ℃ or more so that the molten slag had a similar condition as the slag in the ladle actually completed delineation treatment.

Experimental Example 1)

A portion of the molten slag was introduced into the vessel of the chiller and the slag was cooled while rotating the vessel. At this time, the vessel of the cooling device was rotated at a speed of 100 rpm.

Experimental Example 2)

In order to compare the amount of Ba elution, a part of the molten slag was put into a separate container and cooled as it is at room temperature.

Thereafter, the slag of Experimental Example 1 (Sample 1) and the slag of Experimental Example 2 (Sample 2) were collected, and the slag was crushed for component analysis of the slag.

Then, in order to elute Ba from the crushed slag (Samples 1 and 2), they were immersed in water, respectively, and Ba in the slag was eluted to measure the amount of Ba eluted. At this time, the standard elution time was eluted for 6 hours or 48 hours in the present experiment, the solution may be stirred so that Ba can be eluted smoothly.

Ba elution Psalm 1 980-3300 mg / L Psalm 2 23000 ~ 29000mg / L

Referring to [Table 1], 980 ~ 3300mg / L Ba was eluted in the specimen 1 quenched according to the embodiment of the present invention, 23000 ~ 29000mg / L Ba was eluted in the specimen 2 cooled at room temperature. That is, it can be seen that the amount of Ba eluted from the quenched slag (Sample 1) is reduced by about 85% compared to the amount of Ba eluted from the slag (Sample 2) cooled at room temperature. This is because Ba was stabilized to the Ba-Mn composite oxide phase in the course of quenching the slag, and its elution amount was reduced.

Although the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be defined by the appended claims and equivalents thereof.

10: ladle 12: slag
20: container 22: inner container
24: outer container 30: drive means
40: cooling water supply means 42: cooling water

Claims (12)

Preparing slag;
Injecting the slag into a cooling device rotatably formed;
And cooling the slag to stabilize Ba in the slag into the composite oxide phase.
Slag stabilization method for adjusting the cooling speed of the slag by adjusting the rotational speed of the cooling device. The method according to claim 1,
The slag is a slag stabilization method that is produced in the process of de-lining ferro manganese using a dephosphorization agent containing Ba. The method according to claim 2,
Slag stabilization method for cooling the slag at a rate of 400 ℃ / min or more when the temperature of the slag in the process of stabilizing the slag is 1000 ℃ or more. The method according to claim 3,
The slag cooling is performed by supplying water to the inside of the cooling device to control the temperature of the cooling device slag stabilization. delete The method according to claim 2,
The slag stabilization method Ba in the slag is stabilized in the Ba-Mn composite oxide phase. The method of claim 6,
The Ba-Mn composite oxide phase is at least one of 2BaOMnO, BaOMnO and BaO 2 MnO slag stabilization method. The method according to any one of claims 1 to 4, 6, and 7,
After stabilizing the slag, a further processing step for recovering Ba remaining in the slag is performed. The method according to claim 8,
The further processing step,
Immersing the slag in a solvent to elute Ba in the slag;
Separating Ba and the eluted solution from the residue;
Injecting an additive into the solution to produce Ba by-products; And
Slag stabilization method comprising; recovering the by-products. The method of claim 9,
The slag stabilization method of crushing the slag before immersing the slag in a solvent. The method of claim 9,
The additive is a sulfate ion (SO ₄ ^{2 -)} slag stabilizing method containing or carbon dioxide (CO _2). The method of claim 11,
The by-product is BaSO ₄ or BaCO ₃ Slag stabilization method.

Images