JP3107675B2 - Method and apparatus for separating steelmaking slag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for separating steelmaking slag into ferrous and nonferrous components.

[0002]

2. Description of the Related Art Conventionally, steelmaking slag processing has been carried out by (1) a solidification step of solidifying molten slag, and (2) a solidified slag of 10 minutes.
A cooling step of cooling to about 0 ° C., (3) a fine-graining step of crushing to a particle size suitable for magnetic separation, (4) a separation step of iron / slag (non-ferrous) by magnetic separation, and (5) yard aging. This is done by a stabilization process.

For example, in a conventional typical steelmaking slag treatment, each of the above steps is specifically performed as follows. (1) Solidification process: First, slag is discharged on a soil field or an iron plate, and in the case of a soil field, it is allowed to cool for several minutes on an iron plate for 1 to 2 days to be solidified, and the formed solid lump is formed. It is hit with a slag pot or the like from above and crushed to a diameter of about several hundred mm (primary crushing).

(2) Cooling step: Water is sprayed on the primary crushed lump, cooled to about 300 ° C. in about 1 hour (primary cooling), and then discharged onto a dump truck having a loading capacity of about 30 t, for example.
Sprinkle water again on this trolley and usually 100 ℃ in about ten minutes
After cooling to the extent (secondary cooling), it is discharged from the bogie into the water-cooled pit and usually left for several hours to several tens of hours (pit cooling). After water cooling in the pit, the pit is transferred to a yard for drying and cooling, and then stored.

Here, the slag mass contains ground iron dispersed therein, and not only to obtain a product slag composition suitable for roadbed materials and the like, but also to effectively collect and recycle iron. The two need to be separated. For this purpose, the slag mass is crushed and mechanically separated from each other, and then magnetic separation is performed to separate iron reacting to magnetic force from pure slag not reacting. Here, the ground iron also remains in the slag mass after crushing, and in order to reduce the iron content in the slag mass, it is necessary to further promote finer particles by crushing.

(3) Grain refining process: The primary crushed mass sufficiently dried and cooled in the yard storage is converted into a large slag mass and an iron mass by a stamping machine (commonly called “pecker”). Is separated and passed through a sieve sorter (commonly called "grizzly" etc.) to reduce the lump size to a certain level or less, and then crushed to an appropriate particle size by a suitable crusher such as a rod mill (secondary crushing) ). Processing from the yard storage to the secondary crushing usually takes about one whole day and night (24 hours).

(4) Separation step: After secondary crushing, slag and iron are separated by magnetic separation. Thereafter, in order to improve the quality of iron, usually dry or wet grinding is further performed to make the particle size uniform. Magnetic separation and grinding usually take about 60 minutes. (5) Aging step: After being transferred to an aging yard and stored, and after the hydration reaction is advanced and stabilized, it is provided for various uses such as a roadbed material. Usually, this aging period is 12
Months to 36 months.

As described above, the slag treatment requires a very large number of steps and a large amount of time, and not only has the problems of production efficiency and cost that a huge site is required for each treatment step, but also the solidification. During the high temperature period from to the primary cooling (about 300 ° C), hot work is forced, and subsequent crushing,
In each stage of transfer and magnetic separation, work was performed with a large amount of dust, and there was a problem from the viewpoint of the working environment.

On the other hand, the present applicants disclose Japanese Patent Application Laid-Open
In Japanese Patent Publication No. 110703 (JP-B-58-55093), the primary crushing obtained in the step (1) is particularly performed for the purpose of shortening the cooling time and improving the working environment of the above (2) and shortening the aging period of the above (5). Sprinkle the lump in a closed container,
A method of cooling slag and accelerating hydration reaction by using generated high pressure steam and high temperature atmosphere was proposed.

However, in this method, even if the treatment is carried out for a long time, the effect of accelerating the hydration reaction is small and the crushing effect is not obtained at all. Further, Japanese Patent Publication No. 52-47221 discloses that
A converter slag having a sensible heat of 500 ° C. or more is charged into a high-pressure vessel to which water has been added and sealed, and the water is converted into high-pressure steam by the sensible heat of the converter slag. A method of doing so is disclosed.

However, this method has a disadvantage that the slag is cooled in a steam atmosphere and requires a long time to cool, and the slag crushing effect by thermal shock cannot be obtained due to a slow cooling rate. Therefore, the applicant further applied for Japanese Patent Application No. 4-9769.
In No. 9, by limiting the relationship between the watering rate and the steam pressure in the closed container and the treatment time, not only the hydration reaction caused by contact with the cooling water, but also
A method has been proposed in which the quenching is more effectively utilized to induce the crushing effect, and the hydration reaction is further promoted by accelerating the crushing.
According to this method, due to a synergistic effect in which the hydration reaction and the crushing proceed in a chain reaction, (2) the cooling step and (3) the fine-graining step after the solidification are performed in a closed Since it is completed in about a minute, productivity and the working environment are dramatically improved.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for efficiently separating steelmaking slag into ferrous and non-ferrous components by utilizing the above-described slag quenching process.

[0013]

According to the present invention, there is provided, according to the present invention, a step of solidifying molten steelmaking slag by discharging the slag onto a slag pan or a soil field, and roughening the solidified slag by mechanical impact. Step of crushing to obtain a high-temperature coarsely-crushed slag lump, filling the coarsely-crushed slag lump in a core container having an open top and charging it into a pressure vessel, sealing the pressure vessel, Cooling water is sprinkled from above on the slag mass, and the steam generated by the contact between the cooling water and the high-temperature slag,
The inside of the pressure vessel is represented by the following formula (1): 3.50 ≧ P ^0.6 × T ^0.4 ≧ 1.48 (1) P ≦ 15, T ≦ 1, where P: steam pressure (kg / cm ² ), T: Maintaining the relationship between the steam pressure (P) and the treatment time (T) within the range specified by the treatment time (hr), further crushing the coarsely crushed slag mass by rapid cooling with cooling water and slag expansion by hydration. A step of obtaining a fine-grained slag lump having a particle size suitable for magnetic separation, and a step of magnetically separating the fine-grained slag lump to separate iron and non-ferrous components, thereby separating the steelmaking slag. .

In the pressure vessel, the coarsely crushed slag mass is scattered from above.
In order to make it fine by water, coarsely crushed slag
Submerged in the core container or sprinkled without submerging
Speed 5-30ton / hrm^TwoDrain down as
be able to. The temperature of the coarsely crushed slag mass used is 200 ° C
It is desirable that this is the case. Also, the predetermined processing time
(T ₀), The lower limit required for completing the grain refining process
Air pressure (P₀) Is obtained in advance from equation (1), and is being processed.
The water vapor pressure in the pressure vessel fell below this lower limit
Can supply steam to the pressure vessel separately from the cooling water.
it can. The filling height of the coarse crushed slag in the core container is 0.5
About 4 m is appropriate.

The apparatus for separating steelmaking slag of the present invention is capable of receiving a steelmaking slag in a molten state and slag pan or soil for solidifying the solidified slag on the slag pan or soil, and roughly crushing the solidified slag on the slag pan or soil. A mechanical impacting means for forming a lump, the coarsely crushed slag lump is filled in a core container having an open top and charged into a pressure vessel, and the pressure vessel is sealed. , And water vapor generated by the contact between the cooling water and the high-temperature slag flows through the pressure vessel in the following formula (1): 3.50 ≧ P ^0.6 × T ^0.4 ≧ 1.48 (1) P ≦ 15, T ≦ 1, provided that P: steam pressure (kg / cm ² ), T: the relationship between steam pressure (P) and treatment time (T) within the range defined by treatment time (hr) The above roughening is caused by rapid cooling with cooling water and slag expansion by hydration. A pressure vessel for further crushing the crushed slag mass to make a fine slag mass having a particle size suitable for the following magnetic centrifugal separator, and a magnetic centrifugal separator for magnetically separating the fine slag mass into iron and non-ferrous components. It is characterized by having.

[0016]

In the present invention, water is sprayed in a pressure vessel, the coarsely crushed slag mass is refined by thermal shock due to quenching and expansion due to the hydration reaction, and the obtained fine slag mass is directly subjected to magnetic separation by magnetic force. A large-scale site is not required because a sufficient processing equipment is sufficient, and since processing is performed in a closed container, dust and high heat are not released into the work environment, cooling from high temperatures (conventional process (2)) Granulation (conventional process (3)) can be performed simultaneously and in a short time, and iron and non-ferrous components can be efficiently separated by the next magnetic separation.

Free CaO is present in steelmaking slag and reacts with water to cause a hydration reaction represented by the following formula. Since _{CaO + H 2 O = Ca (} OH) 2 reaction product Ca (OH) ₂ on the right-hand side lower density than the left side of CaO, the expansion takes place by the hydration reaction. Therefore, in order to use the slag for applications such as roadbed materials, it is necessary to sufficiently advance and stabilize this hydration reaction.

In the present invention, the relationship between the steam pressure (P) and the treatment time (T) is limited to the range of the expression (1), thereby inducing self-crushing of the slag, which further promotes the hydration reaction. . In other words, free C in slag by self-crushing
The contact area between aO and H ₂ O is increased, the absolute amount of both involved in the hydration reaction is increased, and eventually the progress of the hydration reaction as a whole slag is promoted.

Since the above hydration reaction is also an exothermic reaction, the equilibrium shifts to the right side of the above equation, that is, to the hydration progress side by cooling, but if the slag temperature becomes too low, the reaction rate itself becomes slow. In the present invention, maintaining steam at a high pressure not only improves the reaction rate at which the slag hydration reaction proceeds to the right side due to the high pressure, but also maintains the optimum slag temperature for the hydration reaction by maintaining the saturated steam temperature. There is also.

When the coarsely crushed slag in the core vessel is submerged by water sprinkling from above, the water sprinkling speed does not need to be particularly limited, and the steam pressure and the submerged state of the slag in the range of the formula (1) can be maintained. Any value within the range is acceptable. When draining from below the packed bed of coarsely crushed slag during sprinkling without submerging,
It is desirable that the watering speed is in the range of 5 to 30 ton / hrm ² . By setting the water sprinkling speed to 5 ton / hrm ² or more, it is possible to spin the cooling water flowing in the coarsely crushed slag packed bed in the core container and uniformly apply the cooling water. However, even if the sprinkling speed is higher than 30 ton / hrm ² , the above-mentioned uniform sprinkling effect is not further improved, and the steam temperature in the pressure vessel is rather lowered.

When the steam pressure within the specified range cannot be maintained only by the steam generated inside the pressure vessel, it is possible to maintain the pressure within the specified range by supplying steam from the outside separately from the supply of the cooling water. it can. FIG. 1 shows a high-temperature steelmaking slag treatment step (FIG. 1A) according to the present invention in comparison with a conventional method (FIG. 1B). In the figure, the typical required time of each step is added to the right of the step name. According to the present invention, a series of steps conventionally required after solidification and primary crushing to before magnetic separation, namely, primary cooling, secondary cooling, pit cooling, yard storage, bulk metal separation, and secondary crushing are all performed. Process
In a single step of rapid water cooling in a pressure vessel, it can be performed effectively in a short time and without high-temperature radiation and dust contamination to the surrounding environment. That is, by performing the treatment of the present invention after solidification and primary crushing, it is possible to reduce the particle size to a particle size suitable for the magnetic separation process.

Further, by promoting hydration with high-pressure steam, the period required for final yard aging can be greatly reduced. Hereinafter, the present invention will be described in more detail with reference to examples.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a slag processing step according to the method of the present invention will be described with reference to FIG. For example, high-temperature molten slag discharged from a steelmaking furnace such as a converter is put into a waste pan 1, conveyed by a crane 2, and discharged onto a slag pan 3 made of, for example, an iron plate. The hot slag discharged is indicated by reference numeral 4 in the figure.

After the discharged slag 4 is solidified, for example, the waste pan 1 is lowered to strike the solidified slag 4 and coarsely crush. The obtained coarsely crushed slag is filled in an appropriate open-top type core container and charged into a closed container type tank 5.
In the inside, quenching and crushing are performed within the pressure / time condition range of the formula (1) by water spraying from above to obtain fine slag blocks.

The obtained fine slag mass 6 is applied to a magnetic ore separator 7 to separate iron / non-ferrous components. Before moving from the above-mentioned grain refining process to the magnetic separation process, large slag can be removed by a suitable sieve separator if necessary. FIG. 3 shows an example of a processing apparatus for performing the grain refinement step.

The core container 12 for accommodating the solidified coarsely crushed slag mass 11 is a container having an open top and a bottom 12A serving as a plate. The pressure vessel 13 accommodating the core container 12 therein carries out the loading / unloading of the core container 12 by opening the upper sealing lid 13A, and closes the container when the processing is executed to thereby provide the pressure vessel 13 with respect to the outside. Keep closed. At the top of the pressure vessel 13, this closed door 13A
The water injection nozzle 4 receiving the supply of the cooling water 28 through the opening is opened downward. A supply port 15 for auxiliary pressurizing steam is provided at the upper side of the pressure vessel 13. Further, a discharge port 1 for excess steam is provided on a lower side surface of the pressure vessel 13.
6 is provided with a discharge port 17 for surplus water at the bottom. Further, in the gap between the pressure vessel 13 and the core container 12, a sealing material 29 is provided above the water vapor discharge port 16, and the steam generated in the core container 12 must
A to pass through.

The core container 12 containing the crushed slag lump 11 therein is carried into and out of the pressure vessel 13 by carrying-in / out means (not shown) such as a suitable crane. The steam pressure (P) in the pressure vessel 13 is
It is detected by a pressure gauge 18 attached to the upper side of the pressure vessel.

When the pressure is excessive, the pressure regulating valve 19 is operated, and when the pressure is insufficient, the auxiliary pressurized steam supply is performed so that the relationship between the steam pressure detected in this way and the predetermined processing time satisfies the equation (1). The flow control valve 20 is operated manually or automatically. Cooling water to the water injection nozzle 14 is supplied from a water supply tank 21 via a pump 22 via a flow control valve 23.

Excess steam (exhausted steam) is guided from the outlet 16 to the drain tank 24, and from the steam dissipation tower 25 to the outside through the pressure regulating valve 19 which is initially set so as to satisfy the relationship between the specified steam pressure and the processing time. Released into the environment. Cooling water 28 instead of discharging exhaust steam into the external environment
The cooling water may be discharged to increase the temperature of the cooling water. The auxiliary pressurized steam is supplied from an appropriate factory pipe 26 or the like to the pressure vessel 13 through the flow control valve 20 via the pressure control valve 27 as required.

A typical procedure for performing the slag cooling and grain refining treatment in the process using the apparatus shown in FIG. 3 is as follows. High-temperature steelmaking slag 11 after solidification and coarse crushing (primary crushing)
Is filled into the core container 12 to a height of, for example, 1 m. The effect of the treatment of the present invention can be obtained if the temperature of the solidified high-temperature slag is 200 ° C. or higher. Slag filling height is 0.5-4m
This is advantageous in that the drift of cooling water in the core container is prevented and cooling is performed uniformly. The sealing lid 13A is opened, and the core container 12 filled with the slag is charged into the pressure container 13. After closing the sealing lid 13A to make the inside of the pressure vessel 13 hermetically sealed, the pump 22 and the flow control valve 2
3 is operated to supply cooling water 28 from the water supply tank 21 to the water injection nozzle 14, and water is sprayed from above onto the slag 11 filled in the core container 12 in the pressure vessel 13. The injected cooling water comes into contact with the high-temperature slag to form steam, and the pressure vessel 13
Increase the pressure inside. Further, since the space between the pressure vessel 13 and the core vessel 12 is blocked by a sealing material 29 and water vapor cannot pass through, the water vapor generated sequentially from above is
At the same time as the pressure inside the pressure vessel 13 is increased, the pressure vessel 13 moves from the upper side to the lower side due to the pressure difference between the upper and lower sides. At this time, since the cooling water is promoted to move downward in the core container 12 as if pressed by the water vapor at the same time as the steam, the cooling water flowing down in the slag 11 filled in the core container 12 is promoted, and a large drift prevention effect is obtained. Is obtained. The water in the core container flows down to the bottom of the pressure container 3 through the bottom plate 12A, and reaches the drain tank 24 through the pipe 16 together with the water vapor, where the water and water are separated. The water in the pressure vessel 13 is discharged from the surplus water drain 17 by opening the on-off valve 30 after the quenching process is completed.

The pressure in the pressure vessel 13 is detected by a pressure gauge 18, and when the pressure is excessive, the pressure control valve 19 is operated. When the pressure is insufficient, the auxiliary pressure control steam flow control valve 20 is operated (manually or automatically). Is adjusted to fall within the specified range. For example, the lower limit of the steam pressure (P ₀ ) required to complete the process in the predetermined process time (T ₀ ) is obtained in advance from equation (1), and the steam pressure in the pressure vessel during the process is equal to or lower than the lower limit. When is reached, supply steam for auxiliary pressurization. For safety, the pressure vessel 13 may be provided with a safety valve (not shown).

In this embodiment, an example is described in which the core container filled with slag is charged and discharged from above the pressure vessel. However, a closed lid is provided on the side of the pressure vessel, and the core container filled with slag is provided. Can be implemented in the same manner when the structure is configured to charge and discharge in the horizontal direction.

[0033]

As described above, according to the present invention,
By utilizing the slag quenching process performed by watering in a closed tank, steelmaking slag can be efficiently separated into ferrous and non-ferrous components.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a typical procedure of a high-temperature steelmaking slag treatment according to the present invention as compared with a conventional method.

FIG. 2 is a process diagram showing an example of a high-temperature steelmaking slag treatment process of the present invention.

FIG. 3 is a layout diagram showing a slag quenching device used in the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Waste pan 2 ... Crane 3 ... Slag pan 4 ... High temperature slag 4 5 ... Closed container type tank 6 ... Fine-grained slag lump 11 ... Solidified high temperature steelmaking slag 12 ... Core container (The bottom with an open top 13) Pressure vessel 13A ... Sealing lid on top of pressure vessel 13 14 ... Injection nozzle 15 ... Supply port for auxiliary pressurized steam 16 ... Exhaust steam outlet 17 ... Exhaust moisture outlet 18 ... Pressure gauge 19 ... Pressure regulation Valve 20 ... Flow regulating valve for supplying steam for auxiliary pressurization 21 ... Water supply tank 22 ... Pump 23 ... Flow regulating valve 24 ... Drain tank 25 ... Steam dispersing tower 26 ... Factory piping 27 ... Pressure regulating valve 28 ... Cooling water 29 ... Seal Material 30 ... On-off valve

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification code FI F27D 15/02 F27D 15/02 A (72) Inventor Shinji Matsuo 1 Nishinosu Oji, Oita City, Oita Prefecture Nippon Steel Corporation Oita Inside the steelworks (72) Inventor Tsukasa Kashiwara 1 Oishi, Oita, Oita City, Oita Prefecture Nippon Steel Corporation Inside the Oita Works (72) Inventor Toshiaki Kudo 1, 1 Nishinosu, Oita City, Oita Prefecture Nippon Steel Corporation Oita Inside the ironworks (72) Inventor Tetsuo Imi Oita, Oita, Oita, Nishi-no-Shi, 1 Nippon Steel Corporation Inside the Oita Steel Works (72) Inventor Sumori Hori, 1 Oita, Oita, Oita, Oita-shi Nippon Steel Corporation Oita In the steelworks (56) References JP-A-5-295409 (JP, A) JP-A-6-127984 (JP, A) JP-A-6-256814 (JP, A) JP-A-5 0-134904 (JP, A) JP-A-55-110703 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 5/00-5/02 C21B 3/06-3 / 08 C21C 7/00 F27D 15/00-15/02

Claims (6)

(57) [Claims] 1. A step of discharging a molten steel slag in a molten state onto a slag pan or a soil field to be solidified; a step of roughly crushing the solidified slag by mechanical impact to obtain a high-temperature crushed slag mass; The crushed slag mass is filled in a core container having an open top and charged into a pressure vessel.After sealing the pressure container, cooling water is sprinkled from above onto the slag mass, and cooling water and high temperature Due to the steam generated by the contact with the slag, the inside of the pressure vessel is expressed by the following formula (1): 3.50 ≧ P ^0.6 × T ^0.4 ≧ 1.48 (1) P ≦ 15, T ≦ 1, where P: steam Pressure (kg / cm ² ), T: Slag expansion by quenching with cooling water and hydration while maintaining the relationship between steam pressure (P) and treatment time (T) within the range specified by treatment time (hr) And further crush the above coarsely crushed slag mass, suitable for the following magnetic separation Obtaining a degree of fine grain slag mass, and method of sorting steel slag, characterized in that the fine slag lumps a step of separating by magnetic separation into the iron and non-iron. 2. In the fine-graining step, the coarsely crushed slag mass is submerged in the core container by the water sprinkling, or the water sprinkling speed is 5-30 ton / hrm ² without submerging.
2. The method according to claim 1, wherein the water is drained downward. 3. The method according to claim 1, wherein the temperature of the coarsely crushed slag mass at the start of the quenching treatment by water spraying is 200 ° C. or higher. 4. A lower limit water vapor pressure (P ₀ ) required to complete the processing in a predetermined processing time (T ₀ ) is previously obtained from the equation (1), and the pressure in the pressure vessel during the processing is determined. The method according to any one of claims 1 to 3, wherein when the steam pressure falls below the lower limit, steam is supplied to the pressure vessel separately from the cooling water. 5. The method according to claim 1, wherein the solidified high-temperature slag is filled into the core container so as to have a height of 0.5 to 4 m. . 6. A slag pan or soil for receiving and solidifying a steelmaking slag in a molten state, and mechanical hitting means for roughly crushing the solidified slag on the slag pan or the soil to produce a high-temperature coarsely-crushed slag mass. The above-mentioned coarsely crushed slag mass is filled in a core container having an open top, charged into a pressure container, and after sealing the pressure container, cooling water is sprinkled from above onto the slag mass to cool the slag mass. By the steam generated by the contact between water and the high-temperature slag, the inside of the pressure vessel is expressed by the following formula (1): 3.50 ≧ P ^0.6 × T ^0.4 ≧ 1.48 (1) P ≦ 15, T ≦ 1 P: Steam pressure (kg / cm ² ), T: Rapid cooling and hydration with cooling water while maintaining the relationship between steam pressure (P) and treatment time (T) within the range specified by treatment time (hr) Further crushing the coarsely crushed slag mass by slag expansion by A steelmaking slag comprising: a pressure vessel for forming a fine-grained slag lump having a particle size suitable for a beneficiator; and a magnetic beneficiator for magnetically separating the fine-grained slag lump into iron and non-ferrous components. Sorting equipment.