JP2002308662A - Production process of slag hardened body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slag hardened body production process by which problems such as strength deficiency of a slag hardened body produced by using converter slag and/or ladle-refining slag as a part of the raw material, generation of cracks in the hardened body and expansion of the hardened body due to free MgO, can be solved all at once. SOLUTION: This slag hardened body is produced by mixing water, granular steelmaking slag and an SiO2 -containing material having latent hydraulicity together to obtain a mix and hardening the mix, wherein, as the steelmaking slag, converter slag and/or ladle-refining slag, each containing <=1 mass % unslagged MgO and <=10 mass % crystallized MgO, is used; as the SiO2 - containing material having latent hydraulicity, a blast-furnace slag fine powder is used, and the ratio of the total content of fractions of the converter slag and/or ladle-refining slag, each of which fractions has <=1.18 mm granule size, to the total content of all the components excluding water of the mix is 10-90 mass %, and the ratio of the blast-furnace slag fine powder content to the total content of all the components excluding water of the mix, is 9-40 mass %.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hardened slag body, and more particularly, to a converter slag and / or powdery granular slag which has been difficult to use effectively as a roadbed material or the like, in particular. Alternatively, the present invention relates to a technique of using a ladle refining slag as a main raw material and forming a hardened body with cracks reduced as much as possible.

[0002]

2. Description of the Related Art Slag generated in a steel making process has a high basicity (expressed as CaO / SiO ₂ ) and contains a large amount of free CaO, so that it easily absorbs moisture and expands easily. It is not suitable for use as a construction material, and its treatment is extremely difficult. Therefore, several attempts have been made to actively utilize such steelmaking slag.

For example, JP-A-10-152364 discloses that one or two of an aggregate containing steelmaking slag, a silica-containing substance having latent hydraulic property, and a silica-containing substance having pozzolan reactivity are used. A hydrated hardened product using steelmaking slag, characterized by containing a binder hardened by a hydration reaction containing at least 10% by weight.
Further, as another example, Japanese Patent Application Laid-Open No. Hei 2-233439 discloses a method in which a binder, fine aggregate, and coarse aggregate are all crushed or crushed into steel slag (including blast furnace slag) and blast furnace slag is used as a binder. And a slag block containing steelmaking slag. Further, Japanese Patent Application Laid-Open No.
No. 6 discloses that after crushing the converter slag to 5 mm or less, magnetic separation,
After drying, the specific surface area is 3000-5000 cm ²
/ G, and this converter slag fine powder is
Water content ratio is 1% or less and specific surface area is 3800-4200cm
An example of blast furnace cement using converter slag obtained by mixing 10 to 30% by weight of blast furnace slag fine powder of ² / g is disclosed. In addition, Japanese Unexamined Patent Publication (Kokai) No. 59-169966 discloses a reinforced roadbed material in which dust-collected dust generated in a converter slag crushing facility is added to and mixed with granulated blast furnace slag in an absolute dry weight ratio of 10 to 60%. ing.

[0004] Here, the steelmaking slag means slag formed in any smelting vessel used for smelting molten steel, and includes hot metal pretreatment slag, converter slag, electric furnace slag, and the like. Smelting reduction furnace slag, stainless steel decarburizing furnace slag, and secondary refining slag to obtain high Cr molten steel (smelting treatment of molten steel from a converter or electric furnace into a ladle in a vacuum degassing tank or as it is) Occurs when you do)
There is. Of these, the ladle refining slag referred to in the present invention is:
This is slag generated during secondary refining such as desulfurization, deoxidation, decarburization, and degassing of molten steel in a ladle refining facility such as VOD, RH, DH, and LF.

[0005]

However, the inventor of the present invention attempted to produce a hardened slag from a converter slag and / or a ladle refining slag as a raw material using the above-mentioned conventional technology. The problem became clear.

First, Japanese Patent Application Laid-Open No. 10-152364,
JP-A-2-233538 and JP-A-142624
A slag hardened body (hereinafter simply referred to as a hardened body) was trial-produced according to the method disclosed in Japanese Patent Publication No. 6-206, but if some steelmaking slag was used, the obtained hardened body had a compressive strength of 20 N / m
It was less than m ^{2, making} it unsuitable for use as a substitute for cement and concrete. In addition, it has been found that many cracks are generated, and it is completely unusable for applications such as hardened construction blocks that require strength and beautiful appearance. Further, JP-A-10-152
Even if a steelmaking slag having a water immersion expansion ratio of 0.5% or less disclosed in Japanese Patent Publication No. 364 is used, the compression strength of the hardened body is 2%.
It was less than 0 N / mm ² and cracks occurred.

[0007] When the cause was investigated in detail, the slag and / or magnesia clinker added to the slag for the purpose of protecting the refractory lining of the converter and ladle in recent years showed that the converter slag and / or Or ladle refining slag MgO
Although the converter slag and / or ladle refining slag having a high concentration of MgO are used, free MgO contained in the converter slag and / or ladle refining slag during water curing is converted to water. It was found that the cured product collapsed due to the sum expansion. That is, free MgO, unlike free CaO, does not easily become a stable hydroxide by aging treatment such as steam aging, and the hydration reaction proceeds slowly, so that the strength development of the cured product is delayed, You do it. Here, free MgO includes unslagged Mg that has melted during refining.
O and crystallized MgO generated when slag in a molten state or a mixed state of a melt and a solid is solidified in a cooling process are present.

Therefore, the present inventor selected converter slag and / or ladle refining slag containing almost no free MgO as steelmaking slag, and tried to produce a hardened body by the same method as the technique described in the above publication. , Compressed strength of 20N
/ Mm ^2, and many cracks may occur, and no material that can be used as a substitute for cement and concrete was obtained. Also, JP-A-1-126
No. 246, the specific surface area is 3000 c.
When a converter slag and / or a ladle refining slag having a particle size of m ² / g or more, that is, a particle size of about 0.07 mm or less was included, hardening hardly occurred. Further, Japanese Unexamined Patent Publication No.
When an attempt was made to produce a cured product by the technique described in Japanese Patent Application Publication No. 169966, only a slag aggregated, but a cured product like concrete could not be obtained.

The present invention addresses the problems of insufficient strength, cracking, expansion caused by free MgO, and the like of a hardened slag obtained by using such converter slag and ladle refining slag as a part of raw materials. It is an object of the present invention to provide a method of manufacturing a slag cured body that can be solved.

[0010]

Means for Solving the Problems The inventor has conducted intensive studies in order to achieve the above object, and has embodied the results in the present invention.

That is, according to the present invention, there is provided a method for producing a hardened slag by kneading powdery and granular steelmaking slag and an SiO ₂ -containing substance having latent hydraulic properties with water. Mass% or less and crystallized Mg
A converter slag and / or ladle refining slag having O of 10% by mass or less is used as the blast furnace slag fine powder as the SiO ₂ -containing substance having the latent hydraulic property, and the particle size of all the mixed substances except water is 1. A method for producing a hardened slag, wherein the content of the converter slag and / or ladle refining slag of 18 mm or less is 10 to 90% by mass, and the content of blast furnace slag fine powder is 9 to 40% by mass. It is.

Further, the present invention provides a method for producing a hardened slag by kneading powdery steelmaking slag and an SiO ₂ -containing substance having latent hydraulic properties with water, wherein the steelmaking slag contains one or more unslagged MgO. Converter slag and / or ladle refining slag having a mass of not more than 10% by mass and crystallized MgO of not more than 10% by mass are obtained by using blast furnace slag fine powder and fly ash as a SiO ₂ -containing substance having latent hydraulic properties, and The content of the converter slag and / or ladle refining slag having a particle size of 1.18 mm or less in all the compounded substances except for
Mass%, blast furnace slag fine powder content of 3 to 36 mass%,
The fly ash content is 1.5 to 30% by mass, and the mass ratio of the fly ash content to the total content of the blast furnace slag fine powder and the fly ash is 0.1 to 0.7.
5. A method for producing a hardened slag body, the method comprising:

In this case, the content of the converter slag and / or the ladle refining slag with respect to the total content of the blast furnace slag fine powder, fly ash and the converter slag and / or ladle refining slag having a particle size of 1.8 mm or less is used. If the mass ratio exceeds 0.2,
Alternatively, one or more kinds selected from oxides, hydroxides, sulfates, and chlorides of alkali metals and / or alkaline earth metals may be further added to the blast furnace slag fine powder to all the compounded substances except for the water. 0.1 based on the total content of fly ash.
It is preferable to add 2 to 20% by mass. In addition, naphthalene sulfonic acids and / or polycarboxylic acids are further added to all the blended substances except for the water, and blast furnace slag fine powder, fly ash, converter slag having a particle size of 0.1 mm or less and / or ladle refining slag are refined. It is preferable to add 0.1 to 2.0% by mass based on the total content.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail according to the circumstances leading to the invention.

First, the inventor of the present invention discloses a method for producing a hardened slag by kneading a powdery steelmaking slag and an SiO ₂ -containing substance having a potential hydraulic property with water. 1% by mass or less and crystallized Mg
A converter slag and a ladle refining slag in which O is 10% by mass or less are used. This is disclosed in
According to the methods disclosed in JP-A-152364 and JP-A-2-233593, when a cured product was trial-produced using these slags as a main raw material, the resulting cured product had reduced strength and cracks. This is because it has been found that by appropriately adjusting the amount, a cured product having high strength and almost no cracks can be obtained. In addition, the inventor adopted a converter slag and a ladle refining slag in which unslagged MgO is 1% by mass or less and crystallized MgO is 10% by mass or less, particularly as steelmaking slag as follows. Based on thoughts.

(1) Compared with other steelmaking slag, CaO
/ SiO ₂ is as high as 2 or more, so the slag contains a large amount of 2CaO · SiO ₂ having high activity. Therefore, it greatly contributes to the acceleration of the curing reaction, and can itself be a substitute for blast furnace slag fine powder or fly ash.

(2) Compared with other steelmaking slags, it contains a large amount of iron, and therefore has a higher specific gravity. Therefore, the specific gravity of the cured body is increased, and when used as an offshore structure such as a wave-dissipating block, the wave stability is excellent.

(3) It is possible to prevent a decrease in strength due to hydration expansion of free MgO and generation of cracks. Then, based on the above-mentioned idea, the inventor conducted research on using a converter slag and ladle refining slag containing free MgO to obtain a cured product that eliminates strength reduction and crack generation due to hydration expansion of free MgO. The experiment was repeated to find out the effect of the hydration swelling of free MgO on the produced cured product.

As a result, it was found that, among free MgO, the presence of unslagged MgO, in particular, had a very large effect on the reduction in strength of the cured product and the occurrence of cracks. That is, the relationship between the unslagged MgO concentration in the converter slag and the compressive strength of the cured product is shown in FIG. 1. It is clear that when the unslagged MgO concentration exceeds 1% by mass, the strength decreases. It is. Also,
As a result of repeated experiments, as shown in FIG.
It was also found that when the gO concentration exceeded 10% by mass, the strength decreased.

Therefore, the inventor has made this finding one of the requirements of the present invention. That is, converter slag and / or
Or 1% by mass of unslagged MgO contained in ladle refining slag
In the following, by setting the crystallized MgO to 10% by mass, it is possible to prevent the strength reduction and the occurrence of cracks due to the hydration expansion of the free MgO of the cured product. The converter slag and the ladle refining slag used in the present invention are preferably subjected to aging treatment beforehand to convert free CaO into stable Ca (OH) ₂ or CaCO ₃ . That is, JIS A
80 ° C x 6 hours / day x 10 specified in 5015
It is preferable to use a converter slag and a ladle refining slag having an expansion rate of 1.5% or less according to a daily water immersion expansion test. If the expansion coefficient exceeds 1.5%, the strength of the cured product is reduced and cracks occur.

However, as described above, free MgO does not easily become a stable hydroxide by the aging treatment, and the hydration reaction proceeds slowly. For example, free CaO
1% by mass of unslagged MgO containing no
JIS for converter slag and ladle refining slag with 10% by mass
The expansion rate of A 5015 at 80 ° C. × 6 hours / day × 10 days is about 1.0%, but the expansion continues without stopping after 10 days. Therefore, it is considered that merely stabilizing the free CaO is not sufficient, and the improvement of the strength of the obtained cured product and the suppression of the generation of cracks are not considered to be satisfactory.

Therefore, the inventor of the present invention has taken countermeasures such that the unslagged MgO is 1% by mass or less and the crystallized MgO is 1% by mass.
When using converter slag and ladle refining slag of 0% by mass or less, it is conceived that a portion having a particle size of 1.18 mm or less has a content of 10 to 90% by mass in all the substances except water. did. A detailed investigation of the portion of the slag that greatly contributes to the curing reaction revealed that those having a particle size of 1.18 mm or less had particularly good reactivity, had a high strength in the obtained cured product, and had significant cracking. Because they found it to be smaller. In addition, it was also found that by using these slags as raw materials for the cured product, elution of F, B, Se, and V from the slag, which is an environmental problem, can be suppressed. Then, the inventor has found this finding, that is, a particle size of 1.18 mm or less contained in converter slag and ladle refining slag in which unslagged MgO is 1% by mass or less and crystallized MgO is 10% by mass or less. Regarding the content of the part in the whole compounding substance, it will be explained later that the restriction of 10 to 90% by mass is added to the requirement of the present invention. This means that among the converter slag and ladle refining slag in which the unslagged MgO used in the compounding is 1% by mass or less and the crystallized MgO is 10% by mass or less, those having a larger particle size are used. It does not prevent that is included.
Converter slag and ladle refining slag with unslagged MgO having a large particle size of 1% by mass or less and crystallized MgO of 10% by mass or less only mean that it was difficult to be pulverized in the pulverization process. This is because the binder contributes to the production of a cured product. Here, the particle size in the present invention is a numerical value determined by sieving, and may be measured by a method specified in JIS A1102 or the like.

Next, SiO having latent hydraulicity to react with converter slag and / or ladle refining slag having unslagged MgO of 1% by mass or less and crystallized MgO of 10% by mass or less is used.
_{2 The} substances contained were examined. As a result, it was found that blast furnace slag fine powder is preferable as the SiO ₂ -containing substance. The blast furnace slag fine powder referred to here is obtained by crushing granulated blast furnace slag, and has a particle size of about 0.1 mm or less,
That is, the specific surface area by the Blaine method is about 3000 cm ² /
g or more are preferable. Also, about 4000 cm ² / g
Use of the above blast furnace slag fine powder is more preferable because of higher activity.

The appropriate blending amount of the blast furnace slag fine powder is determined in relation to the amount of the converter slag and / or the ladle refining slag, and the proper blending amount is 5 to 40.
% By mass. The present invention has been completed by adding this limitation to the above two requirements. The reason for limiting the amount of blast furnace slag fine powder used is as follows. That is, the content of converter slag and / or ladle refining slag in which unslagged MgO having a particle size of 1.18 mm or less is 1% by mass or less and crystallized MgO is 10% by mass or less is less than 10% by mass, or If the content of the blast furnace slag fine powder exceeds 40% by mass, the supply of alkali (or alkaline earth) ions which react with SiO ₂ and harden relatively tends to be insufficient, and the strength of the obtained hardened body decreases. It is. On the other hand, the content of converter slag and / or ladle refining slag in which unslagged MgO having a particle size of 1.18 mm or less is 1% by mass or less and crystallized MgO is 10% by mass or less exceeds 90% by mass, or When the content of the blast furnace slag fine powder is less than 5% by mass, CaO having hydration expandability of the converter slag and the ladle refining slag,
This is because SiO ₂ for fixing components such as MgO tends to be insufficient, so that the cured product expands and powders during curing of the obtained cured product, and the strength is significantly reduced.

As described above, the method for producing a hardened slag according to the present invention is directed to a hardened slag obtained by kneading a powdery steelmaking slag and a latent hydraulically-containing latent material of SiO ₂ with water and curing. In the method of producing, as the steelmaking slag, in particular, unslagged MgO is 1% by mass or less and crystallized MgO is 1%.
Using a granular converter slag and / or ladle refining slag of 0% by mass or less and restricting the amount used, and adjusting the amount of blast furnace fine powder to be blended to be appropriate,
It is kneaded and cured with water. Thereby, free MgO in converter slag and ladle refining slag does not cause hydration expansion during curing. As a result, the hardened slag obtained not only has high strength immediately after production, but also does not crack. Further, the cured product can reduce shrinkage due to drying, and as a result, can prevent cracking.

Subsequently, the inventor studied further improvements in the method for producing a cured slag according to the present invention. Then, fly ash has been found as an SiO ₂ latent material having latent hydraulic properties which can be substituted for blast furnace slag fine powder, and another embodiment of the present invention described above is proposed.

The fly ash is ash generated when coal is burned. Not only JIS standard products but also non-standard products can be used. However, JIS A 620
It is preferable to use the 1 specification type I or II type because they are fine powder and have higher activity. By using this as a partial substitute for blast furnace slag fine powder, unslagged MgO is 1% by mass or less and crystallized MgO is 10% by mass.
The reactivity with the following converter slag and ladle refining slag is further improved, and it is possible to suppress the occurrence of cracks in the cured product and to improve the strength after curing for a long time. Furthermore, it is also possible to prevent the occurrence of cracks due to drying shrinkage of the cured product.

When this fly ash is used by mixing it with blast furnace slag fine powder, the appropriate content of the compounding material is 1 mass% or less of unslagged MgO, 10 mass% or less of crystallized MgO, and The converter slag and / or ladle refining slag of 1.18 mm or less are preferably 10 to 90% by mass, the blast furnace slag fine powder is 3 to 36% by mass, and the fly ash is 1.5 to 30% by mass. In this case, the mass ratio of the content of fly ash to the total content of blast furnace slag fine powder and fly ash needs to be 0.1 to 0.75. In particular, the effect was remarkable when the content was 1.5% by weight or more and the mass ratio of the fly ash content to the total content of the blast furnace slag fine powder and the fly ash was 0.1 or more. . However, fly ash tends to be inferior in hardening at room temperature to blast furnace slag fine powder, and the content of fly ash exceeds 30% by mass, or fly ash relative to the total content of blast furnace slag fine powder and fly ash. When the mass ratio of the content exceeds 0.75, the curing of the cured product as a whole is delayed, which is not preferred. Therefore, in the present invention in another form, the content of fly ash is 1.5 to 30% by mass, and the mass ratio of the content of fly ash to the total content of blast furnace slag fine powder and fly ash is 0.1%.
1 to 0.75.

According to further research, blast furnace slag fine powder, fly ash and unslagged MgO are 1% by mass or less, crystallized MgO is 10% by mass or less, and the particle size is 1.18 m.
m or less of the converter slag and / or ladle refining slag in which unslagged MgO is 1% by mass or less and crystallized MgO is 10% by mass or less with respect to the total content of the converter slag and / or the ladle refining slag. It was found that the mass ratio of the content should be more than 0.2. Therefore, the present invention, which also requires this, has been completed. By limiting to such a range, unslagged M
Alkali (or alkaline earth) ions supplied from converter slag or ladle refining slag having gO of 1% by mass or less and crystallized MgO of 10% by mass or less, and SiO ₂ -containing substances having latent hydraulic properties This is because the quantitative balance with the reactive SiO ₂ becomes more appropriate, and the effect of preventing the obtained cured product from cracking increases.

According to the present invention including the above-described alternative embodiments, a remarkable effect can be obtained in improving the strength of the cured product and reducing the occurrence of cracks. However, the present invention further includes an alkali metal and / or an alkaline earth metal. One or more selected from oxides, hydroxides, sulfates, and chlorides are added in an amount of 0.2 to 20% by mass based on the total content of the blast furnace slag fine powder and fly ash, or , Naphthalene sulfonic acids and / or polycarboxylic acids are used in an amount of 0.1 to 20 with respect to the total content of blast furnace slag fine powder, fly ash and converter slag and / or ladle refining slag having a particle size of 0.1 mm or less. A requirement of adding by mass% may be added.

By adding 0.2% by mass or more of one or more selected from oxides, hydroxides, sulfates and chlorides of alkali metals and / or alkaline earth metals, This is because curing can be accelerated, and the time required for curing can be reduced. However,
Even if added in excess of 20% by mass, the effect is saturated, so the upper limit is 20% by mass. Preferred as such materials are Ca (OH) ₂ , NaOH, Ca
O, CaSO ₄ · 2H ₂ O and CaCl _2, and the like.

The addition of naphthalene sulfonic acids and / or polycarboxylic acids improves the kneading properties when kneading the raw materials with water. Therefore, the amount of water required for kneading can be reduced, and as a result, a cured product having higher strength can be obtained. At that time, the amount of their addition
Blast furnace slag fine powder, fly ash and particle size 0.1
If the mass is less than 0.1% by mass with respect to the total content of converter slag and / or ladle refining slag of not more than mm, the effect is poor, and even if added in excess of 2.0% by mass, the effect is saturated. Therefore, the content is preferably limited to 0.1 to 2.0% by mass. As the naphthalenesulfonic acids, Cell Flow 110 manufactured by K & D Fine Chemical Co., Ltd., and Sunflow-H-60 manufactured by Sunflow Co., Ltd. are preferable. Examples of polycarboxylic acids include Gurex Super 200 manufactured by Grace Chemicals Co., Ltd.

[0033]

EXAMPLES In the following, unslagged MgO having a composition shown in Table 1 as a steelmaking slag is 1% by mass or less and crystallized MgO is 10% or less.
Examples and comparative examples using powdery and granular converter slag and / or ladle refining slag of not more than mass% will be described. The blast furnace slag fine powder has a specific surface area of about 4000 cm ² / g by the Blaine method, and fly ash is JIS.
A type 6201 of A6201 was used. (Example 1) 1 crushed unslagged MgO was used as a compounding raw material.
The converter granulated converter slag and / or ladle refining slag, blast furnace slag fine powder, and Ca (OH) ₂ , which are not more than 10% by mass and crystallized MgO is not more than 10% by mass, are kneaded with water and poured into a mold. This was cured in water at 20 ° C. to produce a cured product. Table 2 shows the content and ratio of each raw material in the blend, and the amount of kneading water added. 2 at 20 ° C. of the obtained cured product
Strength after 8 days water curing, surface dry specific gravity, number of surface cracks after 28 days air curing at 20 ° C., strength after 91 days water curing at 20 ° C., Notification of Environment Agency No. 46 after 20 days air curing at 20 ° C. , B, Se, V measured by the method
Is shown in Table 3.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

(Example 2) Granulated converter slag and / or ladle refining slag having a crushed unslagged MgO content of 1% by mass or less and a crystallized MgO of 10% by mass or less as a blending raw material, a blast furnace Slag fine powder, fly ash and Ca
(OH) ₂ is kneaded with water and poured into a mold.
Cured in water at ℃ to produce a cured product. Table 4 shows the content, ratio, and addition amount of kneading water for each raw material in the formulation. Strength of the obtained cured product after curing in water at 20 ° C. for 28 days, surface specific gravity, number of surface cracks after curing in air at 20 ° C. for 28 days, strength after curing in water at 91 ° C. in water at 20 ° C., atmosphere in 28 days at 20 ° C. Notification 46
Table 5 shows the elution amounts of F, B, Se, and V measured by the above method.

[0038]

[Table 4]

[0039]

[Table 5]

(Example 3) Granulated converter slag and / or ladle refining slag having a crushed unslagged MgO content of 1% by mass or less and a crystallized MgO of 10% by mass or less as a blending raw material, a blast furnace Fly ash is added to the slag fine powder, and for some of them, fly ash is added, and Ca (OH) _{2 and} other additives are kneaded with water and poured into a mold.
After curing in water, a cured product was produced. Tables 6 and 7 show the contents, ratios, and addition amounts of kneading water of the respective raw materials in the blend. Strength of the obtained cured product after curing in water at 20 ° C for 28 days, surface dry specific gravity, number of surface cracks after curing in air at 20 ° C for 28 days, strength after curing in water at 20 ° C for 91 days, 28 days in 20 ° C The elution amounts of F, B, Se, and V measured by the Environmental Agency Notification No. 46 after air curing are shown in Tables 8 and 9 collectively. In the examples, cell flow 110 manufactured by K & D Fine Chemical Co., Ltd. was used as naphthalenesulfonic acids, and Darrex Super 200 manufactured by Grace Chemicals Co., Ltd. was used as polycarboxylic acids.

[0041]

[Table 6]

[0042]

[Table 7]

[0043]

[Table 8]

[0044]

[Table 9]

Comparative Example 1% by mass or less of crushed MgO and 10% by mass of crystallized MgO
Converter granulated converter slag and / or ladle refining slag,
Blast furnace slag fine powder, and for some of them, fly ash and Ca (OH) ₂ are kneaded with water under a condition of a content outside the range of the present invention and poured into a mold. After curing, a cured product was produced. Table 10 shows the content, ratio, and addition amount of kneading water for each raw material in the blend. Strength of the obtained cured product after curing in water at 20 ° C for 28 days, surface dry specific gravity, number of surface cracks after curing in air at 20 ° C for 28 days, strength after curing in water at 20 ° C for 91 days, 28 days in 20 ° C F, B, Se, measured by the Environmental Agency Notification No. 46 method after air curing
The elution amount of V is also shown in Table 11.

The number of surface cracks of the cured product in this example and the comparative example is a number that can be visually confirmed.

[0047]

[Table 10]

[0048]

[Table 11]

The results obtained in the above Examples and Comparative Examples can be summarized as follows with reference to the above tables. In other words, among converter granulated converter slag and / or ladle refining slag having unslagged MgO of 1% by mass or less and crystallized MgO of 10% by mass or less, those having a particle size of 1.18 mm or less are contained. In Comparative Examples in which the rate did not satisfy the conditions of the present invention, the surface cracks of the cured product after curing for 28 days were 3 / cm.
² , which was poor in abrasion resistance and cracked or chipped in the cured product during handling. However, in each of the examples of the present invention, all the cured products had cracks of 0.5 / cm ² or less, the cracks were extremely small, and there was no problem of wear resistance, cracking or chipping during handling. Especially blast furnace slag fine powder, fly ash and particle size 0.425m
m or less of unslagged MgO is 1% by mass or less and crystallized Mg
Ratio of the content of converter slag and / or ladle refining slag to the total content of powdery converter slag and / or ladle refining slag in which O is 10% by mass or less (the ratio indicated by C in the table) Is greater than 0.2 by mass, 1-1, 1-
In 3,1-6,1-7,1-9,1-22, cracking number of the cured product becomes even less and 0.4 present / cm ² or less.

Blast furnace slag fine powder, fly ash, and powdery converter slag containing 1% by mass or less of unslagged MgO having a particle size of 0.1 mm or less and crystallized MgO of 10% by mass or less and / or Alternatively, the ratio of the content of the converter slag and / or the ladle refining slag to the total content of the ladle refining slag (the ratio indicated by D in the table) is more than 0.2 by mass, and is 1-10 according to the present invention. In Nos. 1-22, the number of cracks in the cured product was further reduced to 0.3 / cm ² or less.

Further, in each example of Example 2 in which fly ash was added in an appropriate amount in addition to the blast furnace slag fine powder, the number of cracks in the cured product could be further reduced. In addition, various additives _{(Ca (OH) 2, NaOH} , CaSO 4 · 2
In each example of Example 3 to which H ₂ O or the like was added, improvement in the strength of the cured product and reduction in cracking could be achieved. In addition,
In each example, the elution amounts of F, B, Se, and V could be suppressed. Comparative Example 4 was produced with a blending amount and particle size corresponding to the examples in JP-A-2-233538.
The compressive strength of the cured product was low, and almost no effect of suppressing the elution amounts of F, B, Se, and V was observed.

[0052]

As described above, according to the present invention, a slag hardened body having high strength and almost no cracks in the surface layer can be obtained, and F, B, Se, V from raw slag can be obtained.
Elution amount can be suppressed. This hardened body can be used as a wave-dissipating block, a fish reef, a block for creating a seaweed bed, an offshore structure such as an artificial stone, or other concrete substitute, or a roadbed material or earth and wood after crushing. Therefore,
The present invention greatly contributes to the reuse of resources, improvement of the environment, and the like.

[Brief description of the drawings]

FIG. 1 is a view showing the relationship between the concentration of unslagged MgO in converter slag and the compressive strength of a cured product.

FIG. 2 is a diagram showing the relationship between the concentration of crystallized MgO in converter slag and the compressive strength of a cured product.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) (C04B 28/08 C04B 18:08 Z 18:08 22:06 Z 22:06 22:14 A 22:14 22:12 22:12 24:20 24:20 24:04 24:04) 111: 20 111: 20 (72) Inventor Fumio Kogiku 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Technical Research Co., Ltd. In-house F-term (reference) 4G012 JD00 JE02 JE06 MA00 MB08 MB12 PA27 PA29 PB03 PB09 PB10 PB16 PB24 PC03 PC04 PC11 PD01 PE07 4K013 CF01 4K014 AE01 4K070 AB11 BC13 BC14 EA02 EA27

Claims (5)

[Claims] 1. A method for producing a hardened slag by kneading powdery steelmaking slag and an SiO ₂ -containing substance having latent hydraulic properties with water, wherein the steelmaking slag contains 1% by mass or less of unslagged MgO. ,
The converter slag and / or ladle refining slag having crystallized MgO of 10% by mass or less are converted to SiO ₂ having the latent hydraulic property.
The blast furnace slag fine powder is used as the contained material, and the content of the converter slag and / or ladle refining slag having a particle size of 1.18 mm or less in all the blended materials except water is 10 to 9%.
0 mass%, content of blast furnace slag fine powder is 9-40 mass%
A method for producing a hardened slag body. 2. A method for producing a hardened slag by kneading a powdery steelmaking slag and a SiO ₂ -containing substance having latent hydraulic properties with water, wherein the steelmaking slag contains 1% by mass or less of unslagged MgO. ,
A converter slag and / or a ladle refining slag having a crystallization MgO of 10% by mass or less, a blast-furnace slag fine powder and fly ash are used as SiO ₂ -containing substances having latent hydraulic properties, and all compounded substances except water are used. 1.18
mm or less, the content of the converter slag and / or ladle refining slag is 10 to 90% by mass, the content of blast furnace slag fine powder is 3 to 36% by mass, and the content of fly ash is 1.5 to 3%.
A method for producing a hardened slag, wherein the mass ratio of the content of fly ash to the total content of blast furnace slag fine powder and fly ash is 0.1 to 0.75. 3. The content of the converter slag and / or ladle refining slag to the total content of blast furnace slag fine powder, fly ash and converter slag and / or ladle refining slag having a particle size of 1.18 mm or less. The method for producing a cured slag according to claim 1 or 2, wherein the mass ratio is more than 0.2. 4. A blast furnace further comprising at least one selected from the group consisting of oxides, hydroxides, sulfates, and chlorides of alkali metals and / or alkaline earth metals, in all the substances except water. The method for producing a hardened slag according to any one of claims 1 to 3, wherein 0.2 to 20% by mass is added to the total content of the slag fine powder and fly ash. 5. A blast-furnace slag fine powder, fly ash and a particle size of 0.1 m are further added to all the compounding substances except for water, with naphthalenesulfonic acid and / or polycarboxylic acid.
The slag hardened body according to any one of claims 1 to 4, wherein 0.1 to 2.0% by mass is added to the total content of converter slag and / or ladle refining slag of m or less. Manufacturing method.