JPS5835943B2 - Granulation method of molten blast furnace slag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for granulating slag discharged from a blast furnace using a vacuum vessel.

In recent years, with the increase in the size of blast furnaces, the amount of slag discharged from the blast furnaces has also reached an enormous amount, and it is of great industrial benefit to turn this into a resource and use it effectively.

A typical method of effectively utilizing blast furnace slag that has been practiced in the past is to granulate it and use it as aggregate for concrete, etc. Slag), scattering by collision with a rotating body, and even spraying methods are employed.

However, in all of these methods, the granulated blast furnace slag is weak in strength because it foams during the cooling process and many pores are generated, and the equipment required to process it requires a large area. There was a drawback.

As a result of repeated research, the inventors found that blast furnace slag contains N2.
, N2, and CO are contained in large amounts, and that these components gasify in a vacuum.
The invention was completed based on these two facts. In other words, if blast furnace slag containing N2, N2, and CO acid components flows into a depressurized container, these components become gas and are released from the slag. At the same time, the slag is dispersed and granulated.

The degree of vacuum required for this granulation is desirably limited to 200 miHg or less, as shown in FIG. 2, which shows the results obtained in a laboratory.

Since the granulated product granulated by this method is degassed, it becomes dense regardless of the cooling rate.

On the other hand, before the molten blast furnace slag flows down into the reduced pressure vessel, steam
If nitrogen or the like is blown into the material, the inside will foam and lightweight aggregates can be produced.

Next, an apparatus for carrying out this invention method will be explained.

Figure 1 shows an example of the device, where 1 is a vacuum vessel;
2 is a trough, 3 is a closing plate, 4 is a chute, 5 is a screw conveyor for carrying out, and 6 is a belt conveyor for conveyance.

That is, the molten slag discharged from the blast furnace is introduced into the trough 2 through the chute 4 via the slag gutter or the slag ladle, with its flow rate being adjusted, and is allowed to flow down into the reduced pressure vessel 1 through the opening/closing plate 3.

The opening/closing plate 3 uses a low melting point metal plate such as an Al plate or a Cu plate.

When the pressure inside the container is reduced at the start of granulation work, it is installed between the trough and the container and used for the purpose of sealing the container, and after the pressure inside the container has been reduced to zero, the slag flows into the trough 2: f
When the opening and closing plate is melted and the blast furnace slag starts to flow down into the depressurized container and is granulated, the depressurized state is maintained by the steam ejector 9.When the blast furnace slag flows down into the depressurized container 1, the molten slag is contained in the blast furnace slag. The N2, N2, and CO components in the slag become gases when exposed to low pressure and are released from the slag.

During this gas release process, the slag is finely dispersed and granulated.

Then, this blast furnace slag film 8 is degassed and cooled in the reduced pressure container 1 and collected at the bottom of the container, and at the same time is carried out of the container by a screw conveyor 5 built in this part and conveyed by a belt conveyor 6.

Examples of the present invention will be described below.

Example 1 1 ton of molten blast furnace slag having the gas components shown in Table 1
The treatment was carried out by maintaining the inside of the vacuum container at a vacuum level of 10 mπHg using the vacuum processing apparatus with a processing capacity of 50 kg/mm.

As a result, the properties of the blast furnace slag film obtained are shown in Table 2.

As is clear from Table 2, a large amount of blast furnace slag film with a particle size of 2 to 511 LN, which is optimal as an aggregate for cement raw materials, was obtained, and all of the obtained blast furnace slag films of any particle size were of good quality with no air bubbles. It belonged to

Example 2 One ton of molten blast furnace slag having the gas components shown in Table 1,
The inside of the vacuum container was maintained at a vacuum level of 150 mmHg using the vacuum treatment apparatus having a processing capacity of 50 kg/Inm, and steam was blown into the log/iv melting blast furnace slag in the trough to perform the vacuum treatment.

Table 3 shows the properties of the blast furnace slag film obtained as a result.

As is clear from Table 3, a large amount of high quality blast furnace slag film was obtained in this case as well, as in Example 1.

As explained above, according to the method of the present invention, molten blast furnace slag can be easily and effectively granulated simply by using a vacuum vessel, and a blast furnace slag film with excellent strength can be obtained. Extremely effective as a treatment method for molten blast furnace slag,
It is highly practical.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of a reduced pressure treatment apparatus for carrying out the method of the present invention, and FIG. 2 is a chart showing the relationship between the internal pressure of the reduced pressure container and the average particle size. In the figure, 1...decompression vessel, 2...trough,
3...Opening/closing plate, 4...Chute, 5.
・・・・・・Screw container hair for carrying out, 6・・・・・・
- Belt conveyor for conveyance, 7... Molten blast furnace slag, 8... Blast furnace slag membrane, 9... Steam ejector.

Claims (1)

[Claims] 1 In a method of granulating molten blast furnace slag, an atmospheric pressure of 200 m
A method for granulating molten blast furnace slag, which comprises dispersing and granulating the molten slag by flowing the blast furnace slag into a vacuum vessel whose pressure is reduced to mHg or less.