JP4187453B2 - Ladle method for high temperature molten slag - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for receiving a hot molten slag, and more particularly to a method for receiving a hot molten slag for preventing melting of a molten pan and facilitating recycling of the received slag.
[0002]
[Prior art]
In the steelworks, when making molten steel with a predetermined composition from iron ore, molten slag is generated in each process such as blast furnace, hot metal pretreatment, converter, degassing, and continuous casting. These molten slags are generally discharged in a melting pot in each process, and the molten pots are transported to a slag treatment plant by means of transportation such as railways and trucks, and are subjected to predetermined processing such as cooling, magnetic separation, and grinding. After being used, it is reused for roadbed materials and cement materials.
[0003]
Since the melting pot is usually made of casting, when receiving molten slag of several hundreds of degrees, it will melt violently when molten metal with a high melting point is mixed and discharged. After being spread on the floor, it is discarded.
Since solidified slag is easy to be pulverized, dust is easily generated when it is put into the bottom of the pan or when high-temperature molten slag is discharged on the floor-covered solidified slag, so there is also a method of using molten slag instead of solidified slag. It is introduced in Japanese Utility Model Publication No. 53-70993.
[0004]
[Problems to be solved by the invention]
However, the method of receiving the high-temperature molten slag after previously laying the solidified slag and molten slag on the pan bottom in advance suppresses the melting damage of the melting pot, but reduces the capacity that can be received by the amount of floor slag, Molten slag transport efficiency and slag treatment efficiency were reduced.
In addition, when a small amount of Na or P contained in the floor slag is mixed with molten slag and used as a secondary raw material for blast furnace sinter at the slag reuse destination, Since the deterioration of the RDI of the ore and the adverse effect of increasing the P of the blast furnace hot metal using the sintered ore, the recycling destination of the slag has been limited.
Therefore, the present invention does not provide a method for receiving a high-temperature molten slag pan in order to facilitate the recycling of the slag received in the pan and to suppress the decrease in the efficiency of the molten slag treatment, in addition to suppressing the melting loss of the molten pan. It is what.
[0005]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention is a method for treating molten slag generated when a hot metal is desulfurized with a lime-based desulfurizing agent not containing Na or P. From the slag generated in a steel mill , A metal bar having a size of 5 to 200 mm selected by sieving is previously laid in a melting pan, and then molten slag is discharged into the melting pan.
[0006]
According to the present invention, in order to use bullion instead of slag for flooring, not only is it possible to suppress erosion of a molten pot made of cast metal as in the past, but bullion having a higher specific gravity than slag is used. Since it is used, the amount received can be increased, and transport efficiency and slag processing efficiency such as cooling / grinding processing are not reduced. In addition, since the impurities in the slag that adversely affect the slag recycling are removed from the bullion, there is no limitation on the destination of the slag recycling, and there is an effect that the reuse becomes easy.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a method for receiving a high-temperature molten slag pan according to the present invention will be described with reference to the drawings. FIG. 1 illustrates the present invention, and FIG. 2 illustrates an overall processing outline of the slag processing including the present invention.
The present invention relates to a pan for high-temperature molten slag in hot metal pretreatment, which is a pre-process for refining blast furnace hot metal in a converter, for example. In the hot metal preliminary treatment, dephosphorization or desulfurization treatment for removing unnecessary components in the hot metal in advance is performed in order to increase the refining efficiency. In this dephosphorization and desulfurization treatment, dephosphorization or desulfurization agent is added to the hot metal and stirred to oxidize the phosphorus and sulfur content in the hot metal to slag. There are things. Therefore, the molten slag generated in the hot metal preliminary treatment or the like includes P, S, Fe content, Na content and the like in addition to the main composition such as CaO, SiO2, and MgO.
[0008]
Most of these slags generated in the steel industry are reused for various purposes by applying a slag treatment as shown in FIG. One example will be described. The molten slag discharged into the hot metal ladle becomes solid slag that is transported to a slag treatment plant by transport means and cooled by means such as water cooling. This solid slag is thrown into the slag receiving hopper of the slag processing equipment with a work vehicle, sorted through various equipment such as a pulverizer, magnetic separator, sieve, etc., and sized to a predetermined particle size, recovered + 5mm metal, -5mm Metal, powdered slag, sized slag, etc. The recycle destination of these sized slag, for example, + 5mm metal is used as converter coolant, -5mm recovered metal is used as the iron source of sintered material, and powdered slag is used to adjust the basicity of sintered material. Sintering auxiliary materials, cement raw materials, and sized slag are used for cement.
[0009]
The present invention relates to a powdery slag that is subjected to the above-described slag treatment and reused as a sintering auxiliary material, and is a method for suitably slag-treating slag generated by desulfurization in hot metal pretreatment. That is, in the present invention, when receiving hot metal pretreatment slag generated using a lime-based desulfurization agent that does not contain Na and P in a melting pan, the metal bar generated and recovered by the above slag treatment, After laying the floor in an empty receiving pan in advance, the molten slag is received in the pan. Specifically, a +5 mm metal recovered by a magnetic separator at a slag processing facility, preferably 10 to 20% by weight based on the capacity of the metal with a size of 5 mm to 200 mm received through a sieve. To do.
[0010]
In this case, when the molten slag is discharged into the pan in the case of the bullion of less than 5 mm (−5 mm bullion), the particle size of the flooring bullion is too small to be scattered by the dropping force of the molten slag, and the molten slag is melted. The cast iron collides directly with the cast iron at the bottom of the pan and melts the cast iron. If only 200 mm or more of the ingot is used, the gap between the ingots is large and the cast iron is similarly melted.
In particular, the bullion magnetized by the slag treatment equipment has a large part of Fe, and has a larger specific gravity than conventional solid slag with a floor covering, less dust generation, and contains S, Na, etc. Even when the slag is processed, the slag impure component is not mixed in the molten slag when receiving because the slag powder is slightly adhered around the metal.
[0011]
【Example】
The molten slag discharge from the hot metal pretreatment slag desulfurized with a lime-based desulfurization agent was comparatively operated by using solid slag and metal in the floor type of the hot pot.
The hot metal ladle capacity was 20 ton, the solid slag or ingot was 3 tons, and the size of the ingot was 5 mm or less, 5 mm to 200 mm.
As a result of the comparative operation for 3 months, the melting state of the bottom of the pan was slightly observed when the metal was 5 mm or less, but there was no case of the solid slag and the metal 5 to 200 mm.
In addition, the hot metal pan life using 5 to 200 mm of ingot is almost the same as the conventional solid slag service life, and there is almost no influence of Na, P, etc. on the slag components after hot metal pretreatment, There is no problem even when used as a sintering auxiliary material.
[0012]
【The invention's effect】
Since the method of receiving the hot molten slag according to the present invention is as described above, it suppresses the melting loss of the hot metal ladle, facilitates recycling of the received slag, and lowers the molten slag treatment efficiency. There is an effect of suppressing.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a method for receiving a molten slag pan according to the present invention.
FIG. 2 is a flowchart of the entire slag processing to which the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Molten metal 2 Molten slag 3 Base metal 4 Molten metal container 5 Hot metal ladle 6 Transportation means 7 Solid slag 8 Work vehicle 9 Slag receiving hopper 10 Magnetic separator 11 Conveyor 12 Crusher 13 Sieve 14 -5mm recovery metal 15 Powdered slag 16 Sized slag

Claims (1)

Size of 5 to 200 mm selected by magnetic separation and sieving from the slag generated in the steelworks in the method of receiving molten slag when the hot metal is desulfurized with a lime-based desulfurization agent that does not contain Na or P. A method of receiving a high-temperature molten slag, characterized in that a molten metal slag is drained into a molten pan after the bullion is laid in a molten pan in advance.

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