JPS5916921A - Method for removing adhered slag - Google Patents

Abstract

PURPOSE:To efficiently seperate and remove slag adhered to hot-metal vessel, by a method wherein iron oxide dust is added to hot metal in a hot-metal vessel and SiO2 series slag having low melting point is generated by being mixed. CONSTITUTION:Iron oxide dust generated in a great amount at integrated iron and steelmaking works is added into the hot metal 2 received in a mixer car 1 from a lance 3 by using N2 gas as carrier gas, and hot metal 2 is sufficiently mixed. Iron oxide dust reacts on Si, etc. in hot metal 2 and Si series slag with low melting point is formed. The Si series slag is fused in the hot metal 2, violently keeping touch with the adhered slag 5 and the adhered slag 5 is seperated by fusion and floated on the hot metal 2. The adhered slag 5 floated is removed with suction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for separating and removing slag adhering to a hot metal container, typified by a pig iron mixing car, which transports hot metal tapped from a blast furnace to a steelmaking factory before being charged into a converter. Regarding.

In the pig iron mixing car that stores the hot metal that has been tapped from the blast furnace,
Before charging into a converter, the hot metal is generally subjected to preliminary treatments such as desiliconization, dephosphorization, and desulfurization. When hot metal pretreatment is performed on hot metal in the pig iron mixer car in this way, slag adheres to the inside of the pig iron mixer car. For example, when desulfurization treatment is performed as a pretreatment for hot metal, desulfurization slag adheres to the interior of the pig iron mixing car. When the amount of adhered slag (hereinafter referred to as adhered slag) increases in this way, the following problems arise in operation.

(a) The amount of pig iron received by the pig iron mixing car is significantly reduced due to the presence of adhered slag, and the number of pig iron mixing cars required per - times of pig iron tapping increases. (c) If a large amount of slag adheres to the top of the pig iron mixer, the specific gravity of the pig iron mixer will decrease. As the slag shifts significantly upward compared to the designed slag, it may cause an accident such as rollover of the pig iron mixer car when it is tilted.Therefore, it is necessary to remove such adhering slag. Methods have been used in the past. Immediately, the pig iron mixer car is periodically dispatched to a special tailings yard, where the pig iron mixer car is tilted and the adhering slag inside is cooled and disintegrated naturally, thereby being discharged. Such conventional methods for removing adhered slag have the following drawbacks.

(a) A dedicated tailings yard is required. (b) Sufficient consideration must be given to the pollution caused by graphite powder that is scattered when the adhering slag is discharged from the pig iron mixer. (c) Adhering slag must be removed. When the pig iron mixer car is discharged from the pig iron mixer car, the refractory material in the pig iron mixer car undergoes a rapid temperature change due to the drastic cooling of the car, resulting in a spalling phenomenon, which damages the refractory material and destroys the original refractory material. It takes a long time to cool and naturally disintegrate the adhering slag inside the pig iron mixing car.The present invention was made to solve this problem, and it is possible to use the existing hot metal container. In addition, by using iron oxide dust, which is generated in large quantities in steel works, it is possible to easily remove the slag adhered to the hot metal container in a short time without making a large investment, and also to rapidly change the temperature of the hot metal container. The purpose is to provide a method for removing the files without removing them.

The method for removing adhered slag according to the present invention involves adding iron oxide dust to the hot metal in the hot metal container and stirring it to separate and remove the slag that has adhered to the hot metal container.
It is characterized by generating O□ type slag.

In the present invention, since iron oxide dust is added to the hot metal, the fine grains of the dust of 0.5 mm or less are utilized, and the reaction force described below advances in a short time and is still reduced. The iron content will be recovered in the hot metal.

The method of the present invention will be explained in detail below based on the drawings. The drawing is a schematic cross-sectional view showing the implementation state of the method of the present invention.

1 is a pigeon mixer car, and a pigtail receiving port 1a is provided at the top of the car.
It is used to receive and store the hot metal 2 tapped from the blast furnace in the converter, and to transport it to the steelmaking factory in order to charge it into the converter. From the pig iron receiving port 1a, in order to pre-process the hot metal, nitrogen gas is used as a carrier gas before desiliconization, after desulfurization agent, etc. is added to the hot metal 2. A lance 3 for stirring the hot metal 2 and a lance 4 for blowing oxygen gas onto the surface of the hot metal 2 to prevent the temperature of the hot metal 2 from falling are inserted.

In the process of receiving the hot metal 2 tapped from the blast furnace in the pig iron mixer car 1 and transporting it to the steelmaking factory, the hot metal 2 in the pig iron mixer car 1 is added from the lance 3. Hot metal is pre-treated using a desiliconizing agent, a dephosphorizing agent, a desulfurizing agent, etc. When the hot metal is pre-treated in the pig iron mixer 1 in this manner, the adhered slag 5 adheres to the inside of the pig iron mixer 1, and as this slag further accumulates over time, a layer of the adhered slag 5 is formed.

If the weight of the adhered slag 5 on which a layer is formed in this way exceeds a certain level, various operational problems as described above will occur, and it will be necessary to remove this adhered slag 5. However, the present invention As for the method, the method described below is carried out.

That is, the lance 3
Nitrogen gas is added as a carrier gas to iron oxide dust, which is generated in large quantities in the steel works, and at the same time, the mixed pig iron car 1
Thoroughly stir the hot metal 2 inside.

In this way, the hot metal 2 to which iron oxide dust was added was processed into JFLPI.
'Then, iron oxide dust and silicon, etc. in the hot metal
Then, by the reaction shown in the fl1 formula below, low melting point Sin,
, system slag is generated.

2 FeO+Si = 5in2+ 2 Fe
・-Fll produced 5in2 type slag has a low melting point, so it is molten.

Since the 5j02 type slag has good fluidity, it can be melted at any temperature, and the molten 5j02 slag has good fluidity.
, 41", it comes into contact with the adhered slag 5 violently.

As a result, the adhered slag 5 is melted and separated and floats in the hot metal 21-. The adhering slag 5 that has melted and separated and is floating in the hot metal 2' is removed by suction from the inside of the pig iron mixer 1 using an appropriate suction device (not shown) or by sucking it into the hot metal ladle (not shown). ) and then removed by separating it from the hot metal 2 in the hot metal pot.

By removing the adhered slag 5 from the pig iron mixing wheel 1 in this way, there are operational problems when the above-mentioned slag 5 is turned into slag, and further disadvantages of the conventional method of removing the adhered slag 5. In the above explanation, the method of removing slag adhering to the inside of the pig iron mixing car 1 was mentioned, but the method also applies when removing slag adhering to the inside of the hot metal container other than the pig iron mixing car 1. It goes without saying that the method of the present invention can be applied.

Next, examples of the method of the present invention will be described. The method of the present invention was carried out on a pig iron mixer car with a significant amount of adhered slag. That is, iron oxide dust (the composition of which is Fe
O: 70% + CaO: io%, Fe: 20
%) was added together with a carrier gas (nitrogen gas) at a ratio of 15 kg/ton of hot metal. The silicon concentration of the hot metal before adding this oxide dust is 0.50%, and its temperature is 1.
450°C, whereas the hot metal after addition had a silicon concentration of 0.30% and a temperature of 1430°C. Moreover, after addition, the slag was completely melted, and its composition was CaO: 43.7.

5in2: 38.9%+T-Fe: 3-2%
+Others: 14.2%.

After that, all the molten slag and hot metal in the pig iron mixer car were transferred to the hot metal pot, and by visually observing the empty pig iron mixer car, the weight of the empty pig iron mixer car was measured, and the weight of the empty pig iron mixer car was measured. The removal status of the adhered slag inside the pig iron mixer car was investigated by comparing the amount of M in the empty pig iron mixer car that was measured before implementing the method of the present invention. As a result, it was visually confirmed that the slag deposited in the pig iron mixer car was almost completely removed, and the weight of the removed slag was 165 tons before and after implementing the method of the present invention. From the change from 150 tons to 150 tons, it was found that the amount was approximately 15 tons, and it was confirmed that the method of the present invention is extremely excellent as a method for removing adhered slag in pig iron mixing cars.

As detailed above, the present invention is a method for separating and removing slag adhering to a hot metal container, in which iron oxide dust is added to the hot metal in the hot metal container and stirred, thereby producing 5in2 type slag with a low melting point. Therefore, the adhering slag can be easily separated and removed in a short time and without rapidly changing the temperature of the hot metal container. Therefore, the present invention has extremely excellent effects in improving productivity in the pig iron and steel manufacturing process.

[Brief explanation of drawings]

The drawing is a schematic cross-sectional view showing the implementation state of the method of the present invention. ]...Pig iron mixer car 2...Hot metal 3, 4...Lance 5
... Adhesive slag patent applicant Noboru Kono, patent attorney representing Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] 1. In order to separate and remove the slag adhering to the hot metal container,
A method for removing adhered slag, which comprises adding iron oxide dust to hot metal in a hot metal container and stirring the mixture to generate S to2 type slag with a low melting point.