JPH0656487A - Method for treating converter slag - Google Patents

Abstract

(57) [Summary] [Purpose] A large-scale converter slag that is difficult to be crushed by a crusher is made into small lumps at low cost to obtain road materials. [Constitution] A large-scale converter slag cooled in a yard is put into a steam aging slag treatment tank 1. Steam is injected from the steam injection pipe 3 to steam-age the large-scale converter slag 6. The large lump converter slag 6 collapses due to the hydration reaction of free lime and becomes a small lump. This small slag is adjusted to a predetermined particle size by a crushing and sieving device. After adjusting to a predetermined particle size, aging is performed again if necessary. [Effect] Large lump converter slag can be made into small lumps at low cost. Large-scale converter slag can be effectively used as road material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method for effectively using large slag, which is used for landfill, of most converter slag as a road material.

[0002]

2. Description of the Related Art As a general method for treating converter slag, molten slag is poured onto dry ballast, solidified, allowed to cool or sprinkle, and then dug with a bulldozer or the like, and then magnetic separation by a crushing and sieving device. , The grain size is adjusted. The slag adjusted to the specified particle size is used for road materials such as roadbed materials after it has been aged for a certain period of time to almost complete the expansion and collapse peculiar to converter slag. Is used to.

The crushing and sieving device for converter slag is composed of a primary sieve (grizzly), a screen, a magnetic separator, a crusher, etc., and a jaw crusher or a cone crusher used as a crusher is about 300 mm. Since the above large lumps cannot be crushed, the slag that has been slowly cooled in the yard is first sieved with a grizzly to a size of less than 300 mm, and only the bottom of the sieve is magnetically selected and crushed.
On the other hand, most of the large slag on the sieve that exceeds 300 mm is used for landfill.

[0004]

As is well known, since converter slag has a crystalline and hard property, as described above, it is crushed after cooling and adjusted to a predetermined particle size to be used as a roadbed material, etc. Most of the impossible large slag is used for landfill, and therefore a large amount of treatment cost is required.

The large lump slag remains in the yard without being broken into small lumps by a bulldozer, etc., and is a slag lump that is not easily broken, and since the converter slag contains a large amount of metal, it is necessary to use aion, etc. It is not preferable to use the heavy equipment to destroy it because the cost is high.

In the aging treatment with a large lump, the reaction does not easily proceed to the inside of the slag lump, so that the aging cannot be performed completely. Therefore, in order to use the large slag as a road material, it is necessary to crush it, adjust the particle size, and perform aging treatment.

In view of such circumstances, the present invention intends to propose a treatment method capable of making a large lump converter slag, which is used only for landfilling, into small lumps at low cost and effectively utilizing it as a road material. Is what you do.

[0008]

SUMMARY OF THE INVENTION The present invention utilizes the property of unhydrated lime (free lime) contained in converter slag to hydrate and expand when it reacts with water. The gist of this is that the large slag on the primary sieve (grizzly) is steam-aged at atmospheric pressure into small lumps.
The gist is a method of treating the small slag with a crushing and sieving apparatus, and a method of adjusting the small slag to a predetermined particle size with a crushing and sieving apparatus and then aging again.

[0009]

[Function] The free lime contained in the converter slag is a part of the quicklime used during refining that remains unreacted. When it reacts with water, it causes a hydration reaction and expands and collapses.
The higher the free lime in the slag, the more prominent the tendency. Since this collapse phenomenon stabilizes over time, as a method of artificially eliminating the collapse phenomenon of converter slag in a large amount, generally called aging, it is piled up in the atmosphere for a long time to complete the collapse. There is a treatment and an aging treatment method using steam.

The aging treatment method using steam is a method of accelerating the hydration reaction of free lime in the converter slag by heat of steam and excess water, and the aging period is much longer than that of natural aging. There are short advantages. The mechanism of collapse by steam aging is that the free lime existing on the surface of the slag mass hydrates and expands, causing cracks in the slag mass, and the steam entering from the crack further reacts with the free lime inside. That is, the cracks disintegrate by repeating the phenomenon that cracks spread.

Grizzly slag on the sieve (particle size is about 3
(More than 00 mm) is steam-aged under atmospheric pressure, the free lime contained in the converter slag hydrates in a short time, expands and collapses, and becomes small (about 300 mm or less). The small slag mass can be put into a crusher and can be adjusted to a predetermined particle size by a crushing and sieving device. Further, the steam aging causes the large slag to break into smaller lumps, so that the free lime present inside the slag lumps is exposed on the surface, and the hydration reaction is further promoted.

When a large slag containing metal is steam aged, the slag is separated due to the difference in thermal expansion between iron and slag, and the metal is easily recovered.

Further, high-quality roadbed material can be obtained by subjecting the converter slag adjusted to a predetermined particle size by the crushing and sieving apparatus to natural aging or steam aging again as required. In addition, since the slag that has been adjusted to the prescribed particle size has a stable slag collapse phenomenon due to the steam aging that was previously performed, the second aging treatment is the same as conventional aging or steam aging. The time required for aging can be shortened compared to aging for unaged products, and in the case of steam aging, the unit consumption of steam can be greatly reduced.

[0014]

1 and 2 are schematic views illustrating steam aging equipment for carrying out the method of the present invention. Here, steam is introduced into a rectangular slag treatment tank with one side of a side wall serving as a slag loading / unloading gate. A steam aging facility with piping will be described as an example.

In the figure, 1 is a slag processing tank whose bottom and side walls are made of concrete or the like, 2 is a steam supply main pipe, 3 is a steam injection pipe, 4 is a steam flow control valve, 5 is crushed stone, and 6 is a large block. Furnace slag, 7 is a vinyl sheet.

In the steam facility, a steam injection pipe 3 is laid on the bottom surface of a slag treatment tank 1 whose bottom and side walls are made of a structure that does not leak steam (made of concrete, iron plate, etc.), and the steam injection is performed. This is a system in which a converter slag layer 6 is formed on a tube 3 through a crushed stone layer 5 having a predetermined grain size, and steam aging is performed. The crushed stone layer 5 is provided in order to ensure stable vapor permeability and to uniformly diffuse the vapor. The vinyl sheet 7 is provided to prevent the release of steam.

[0017]

[Example 1] The following shows the results of actual aging treatment of large-scale converter slag using steam aging equipment. In the present embodiment, a large-scale converter slag 300 having a size of more than 300 mm is used.
Tons processed. Table 1 shows the steam treatment results at that time.

[0018]

[Table 1]

In this embodiment, about 1 after the start of steam aging.
After hours, the steam spreads over the entire slag layer, and after about 6 hours, a large lump of slag was observed, and after 24 hours, the entire slag had finished collapsing, and the large lump slag collapsed into small lumps of 150 mm or less, The peeling of the metal was also seen.

Next, Table 2 shows the properties of the converter slag obtained by adjusting the particle size of the small slag after steam aging with the existing crushing and sieving equipment. As is clear from Table 2, the slag after particle size adjustment satisfies all the asphalt pavement outlines and can be used as a roadbed material. At the same time, about 12% of the metal was recovered from the converter slag.

[0021]

[Table 2]

[0022]

Example 2 300 tons of converter slag of 25 mm or less obtained in Example 1 was naturally aged for 3 months, and the natural aging slag was subjected to a water immersion expansion test (80 ° C., 6
As a result of conducting Hr / day for 10 days, the water immersion expansion amount was 0.6% before natural aging, but decreased to 0.2% by short-term natural aging. On the other hand, when the slag under the grizzly sieve was adjusted to have the same particle size and naturally aged, it took 12 months to reduce the water immersion expansion amount to 0.6%, which is the same level as in the present invention.

[0023]

Example 3 300 tons of converter slag having a size of 25 mm or less obtained in Example 1 was steam-aged by the steam-aging facility shown in FIG. Water immersion expansion test (80 ° C, 6 hr / day, 10 days) for this slag after steam aging
As a result, the water immersion expansion amount was reduced to 0.2% after only 20 hours of steam aging. The basic unit of steam usage at that time was 20 kg / T, and when combined with the basic unit of steam usage of the first time, it required 44 kg / T. On the other hand, the converter slag under the grizzly sieve was adjusted to the same particle size, and this slag (water immersion expansion amount 3.
As a result of steam aging (5%), it took 48 hours to reduce the water immersion expansion amount to 0.2%, which is comparable to that of the present invention.

[0024]

Industrial Applicability As described above, the present invention is a method of utilizing the collapse phenomenon of slag due to steam aging to spontaneously collapse large lump converter slag to form small lumps, and thus has been used so far for landfill. Grizzly sieving large lump converter slag can be made into lumps at low cost, and it is possible to adjust it to a predetermined particle size with an existing crushing and sieving device, and then adjust it to a predetermined particle size and then age it again. As a result, a large amount of slag having excellent properties as a road material can be obtained. Further, it is possible to easily collect the metal contained in the large-scale converter slag.

[Brief description of drawings]

FIG. 1 is a schematic view illustrating a steam aging facility for carrying out the method of the present invention.

FIG. 2 is a vertical sectional front view taken along the line AA of FIG.

[Explanation of symbols]

 1 Slag processing tank 2 Steam supply main pipe 3 Steam injection pipe 4 Steam flow control valve 5 Crushed stone 6 Large-scale converter slag 7 Vinyl sheet

Claims (2)

[Claims] 1. A slag that has been slowly cooled in a yard, is subjected to steam aging under atmospheric pressure to make small lumps of primary slag on the primary sieve into small lumps, and the small lumps of slag are treated by a crushing and sieving apparatus. Characteristic converter slag treatment method. 2. The primary sieving large slag of the converter slag that has been slowly cooled in a yard is steam-aged at atmospheric pressure into a small lump, and the small slag is crushed and sieved to a predetermined particle size. A method for treating converter slag, which comprises adjusting and then aging again.