JPS581059B2 - Kaishitsuko Saibarasu no Seizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a modified slag ballast, and more particularly to a method for advantageously cooling and agglomerating a modified slag ballast.

Blast furnace slag, which is a large amount of by-product from blast furnaces, is effectively used in various ways.

Blast furnace slag in a molten state (hereinafter referred to as slag) is not used as it is, but is quenched with water to form a slag or slowly cooled and used for various purposes as a slag ballast.

This slag ballast has undergone various modifications in recent years.

For example, as a modification to increase the compressive strength of slag ballast,
It has been proposed to reduce porosity by adding rolling scale, converter slag, Indian iron-manganese ore, etc. to the slag.

In addition, as a modification to fix the sulfur in the slag ballast and prevent this sulfur content from leaching into water, converter slag, rolling scale, Indian iron manganese ore, etc. are added to the slag. It has been proposed to fix the sulfur inside as sulfides of heavy metals (Fe, Mn) that are insoluble in water.

In both of the above methods for producing the modified slag ballast, modifying additives are added to the slag, then poured into a field or dry pit in layers to cool and solidify, and then dug up with a bulldozer.
The crushed slag is crushed in a crusher and sifted into appropriate sizes to produce slag ballast.

However, in the case of the above manufacturing method, a vast processing plant (field)
This requires a lot of time, and also requires crushing work.

Moreover, since the above-mentioned modified products become dense and strong when cooled, it is difficult to crush them using a normal crushing method (crusher).

The uniaxial compressive strength of normal slag ballast is 20 to 24k.
g/cm2, and the above-mentioned modified slag ballast is 25 to 35 kg.
/cm2.

The present invention advantageously solves the above-mentioned problems, and its gist is that when processing molten blast furnace slag that has been modified by adding converter slag, etc. By supplying slag kept at 1300°C or higher,
A method for producing a reformed slag ballast is characterized in that the slag is cooled and transferred and crushed in a high temperature region with low strength.

The present invention will be specifically explained below.

The production of the modified slag ballast according to the present invention is carried out using an inclined rotating cylinder whose outer periphery is cooled.

When the modified molten slag is injected from the upper opening of such an inclined rotating cylinder, the surface of the modified slag quickly solidifies due to the cooling of the outer periphery, and the surface of this inclined rotating cylinder is It is lifted in the direction of rotation, and once lifted to a certain extent, it falls and is crushed by the gravity of the slag.

To explain this situation in more detail, in the first half of the tilted rotary cylinder where the slag rotates in a semi-molten state, the slag that is continuously supplied and the slag that falls due to gravity form a rotating dam while rotating tiltedly. Move to the lower opening side of the cylinder.

In the rear half of the tilted rotary cylinder, this rotating semi-molten slag dam is crushed into smaller pieces by rolling crushing and mutual collision of the slags, cooled, and discharged from the lower opening to form a slag ballast. This is the result.

An example of the device is shown in FIGS. 1 and 2, in which 1 is an inclined rotating cylinder, 2 is a pedestal, 3 is a support roller, 4 is a motor, 5 is a drive shaft, 6, 7 is a drive gear, 8 is a water sprinkling pipe, 9 is a water collection member, 10 is an upper opening, 1
1 is a trough for supplying reformed slag, 12 is a lower opening, and 13 is a conveyor for transporting reformed slag ballast.

When the slag ballast is produced as described above, a vast processing plant (field) is not required, and the crushing work is carried out within the rotary cylinder 1 without requiring a long time.

The reason why the difficult process of crushing the reforming slag as described above is so easily carried out in the inclined rotating cylinder 1 is because the reforming slag has low strength and is at high temperature. This is because a transfer phenomenon occurs.

According to our experience, the reforming slag inside this tilted rotating cylinder is 1
Since it is in a semi-molten state at temperatures above 100℃, it will be crushed by slight transfer, and the strength will increase from 1 to 5 kg/cm2 at temperatures above 800℃.
This strength enables efficient crushing.

However, under the above conditions alone, it may not be possible to produce a modified slag ballast using the tilted rotating cylinder.

That is, even if the reformed molten slag was injected into the inclined rotating cylinder 1, the molten slag adhered to the inner circumferential surface of the inclined rotating cylinder 1 and was lifted in the direction of rotation of the inclined rotating cylinder 1 while solidifying the surface. At this time, this slag does not fall due to gravity and rotates once while adhering to the inner circumferential surface of the inclined rotating cylinder 1, and a ring-shaped deposit is formed over the inner circumferential surface of the inclined rotating cylinder 1. This is a case where the kimono further grows in the axial direction of the tilted rotating cylinder 1.

In this case, since this deposit insulates the cooling water and the reforming slag that is successively supplied, cooling of the reforming slag is hindered, and cooling crushing of the reforming slag cannot be achieved.

As a result of various experimental studies conducted by the present inventors on this point, we found that the formation of the ring-shaped deposits described above is closely related to the temperature of the reforming slag at the time of feeding. It has been found that if the temperature of the slag is 1300°C, preferably 1350°C or higher, no ring-shaped deposits are formed.

Therefore, in the present invention, the upper opening of the inclined rotary cylinder for cooling the outer periphery is heated to 1300°C, preferably 135°C.
Slag at a temperature of 0° C. or higher is supplied, the slag is cooled and crushed at high temperature, and discharged from the lower opening to produce a reformed slag ballast.

The particle size of the obtained modified slag ballast is influenced by the space factor of the slag in the inclined rotating cylinder 1, and especially when this space factor becomes 10% or less, the momentum of the slag in the inclined rotating cylinder 1 decreases significantly. Therefore, the particle size of the resulting ballast becomes large, which is not very desirable, and it is preferable to maintain (adjust) it at 10% or more.

Although the upper limit is not particularly determined, it is generally set at 50% to ensure the momentum of the slag within the tilted rotating cylinder 1.

This space factor is generally expressed by the following formula, and can be adjusted based on this formula.

However, ρ is the bulk specific gravity of slag (g/m3) below 1000℃, A is the cross-sectional area of the tilted rotating cylinder (m3), D is the diameter of 〃 (m), S is the inclination angle of 〃 (°), N is the rotation of 〃 The number (r.p.m.) k is the constant β is the angle of repose of the slag in the tilted rotating cylinder (°) and Q is
〃 is the supply amount (t/H) of reforming slag to.

In the above formula, the preferred range of the inclination angle of the tilted rotary cylinder is in the range of 2 to 10 degrees for the following reason.

First, if the tilt angle of the tilted rotating cylinder exceeds 10°,
Since the supplied reforming slag quickly passes through this oblique rotating cylinder, smooth cooling and crushing of the slag cannot be performed.

On the other hand, if the inclination angle of the tilted rotary cylinder is less than 2°, the slag does not move smoothly to the lower opening within the tilted rotary cylinder, which is undesirable because the amount of slag throughput decreases.

Next, examples of the present invention will be described together with comparative examples.

Example 1 10k9 of rolling scale was added per ton of molten blast furnace slag as a modifier to increase compressive strength,
A slag ballast was produced from the mixed and reformed slag using an apparatus as shown in FIGS. 1 and 2.

Example 2 Modification treatment was carried out by adding and mixing 1.2% of recovered waste acid iron oxide 8 (Fe203) to the molten blast furnace slag (weight) as a modification material to fix the sulfur in the slag. A slag ballast was produced from the molten slag using an apparatus as shown in FIGS. 1 and 2.

Example 3 Particle size 0.2 to 3 was added to molten blast furnace slag as a modifier to increase compressive strength and to fix sulfur in this slag.
A slag ballast was produced from the molten slag obtained by adding and mixing 4% of the converter slag to the molten slag (weight) and reforming the slag using an apparatus as shown in FIGS. 1 and 2.

Comparative example 1 Same as Example 1.

Comparative example 2 Same as Example 2.

Comparative Example 3 A slag ballast was produced from only molten slag using an apparatus as shown in FIGS. 1 and 2.

The embodiments of the above Examples and Comparative Examples are as shown in Table 1 below.

Next, Table 2 shows the particle size structure of the product obtained in the above process.

The temperature of the slag ballast when discharged from the tilted rotating cylinder was 1080°C in Example 1 and 1020°C in Example 2.
℃, Example 3: 975℃, Comparative Example 3: 1105℃.

The properties of the slag ballast obtained in the above manner are compared with those obtained by the conventional method and are shown in Table 3 below.

As described above, according to the present invention, the molten slag that has been previously reformed and heated to 1,300°C, preferably 1,350°C or more is supplied from the upper opening of the inclined rotating cylinder that cools the outer periphery, and the molten slag is cooled and is heated to a high temperature. Since the reformed slag ballast is produced by crushing the slag and discharging it from the lower opening, there is no need for a vast processing plant (field), and the production time can be significantly shortened. Since it is carried out at high temperatures when it is easy to break targets, the slag ballast is already crushed when it is discharged from the lower opening.

Therefore, the crushing work does not have to be difficult as in the conventional case.

Moreover, as is clear from the examples, in the present invention, the temperature at which the reformed slag is supplied to the inclined rotating cylinder is 1300°C, preferably 1350°C or higher, so there is no formation of ring-shaped deposits and the stability is stable. The production of modified slag ballast can be carried out.

In addition, in the present invention, if the modifying material is added and mixed immediately before the upper opening of the tilted rotating cylinder, the temperature drop of the modified slag can be effectively prevented, and furthermore, the modifying material can be preheated. Then it will be even more effective.

[Brief explanation of the drawing]

FIG. 1 is a side view of an example of an apparatus for carrying out the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. 1... Inclined rotating cylinder, 2... Frame, 3... Support roller, 4... Motor, 5... Drive shaft, 6, 7... Drive gear, 8... Water sprinkling piping, 9... Water collection member , 10... Upper opening, 11... Gutter, 12... Lower opening, 13... Conveyor.

Claims (1)

[Claims] 1. When processing molten blast furnace slag that has been modified by adding converter slag, etc., molten slag maintained at 1300°C or higher is supplied from the upper opening of an inclined rotating cylinder whose outer periphery has been cooled to cool the molten slag. At the same time, a method for producing modified slag ballast is characterized in that transfer crushing is carried out in a high temperature range with low strength.