JP2011051889A - Method for manufacturing slag hardened body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing slag hardened body solving problems such as insufficient strength, generation of crack and expansion due to free MgO of a slag hardened body obtained by using converter slag and ladle refining slag as a part of the raw material, at a bound. <P>SOLUTION: In the method for manufacturing the slag hardened body by compounding a particulate steel-making slag and a substance containing SiO<SB>2</SB>having latent hydraulicity with water, the converter slag of un-smelted MgO of 1 mass% or less and crystallized MgO of 10 mass% or less and/or the ladle refining slag are used as steel-making slag, and blast furnace slag fine powder is used as the substance containing SiO<SB>2</SB>having latent hydraulicity, wherein the content of the converter slag and/or the ladle refining slag having a particle size of 1.18 mm or less in the whole compounding material except water is made to be 10 to 90 mass% and the content of the blast furnace slag fine powder is made to be 9 to 40 mass%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a slag hardened body, and in particular, mainly steelmaking slag, in particular, powdered converter slag and / or ladle smelting slag that has been difficult to effectively use as roadbed materials. The present invention relates to a technology for using as a raw material a cured body with as few cracks as possible.

The slag generated in the steelmaking process has high basicity (expressed as CaO / SiO ₂ ) and contains a large amount of free CaO, so it easily absorbs moisture and is used as civil engineering and construction materials like blast furnace slag. However, the processing is extremely difficult. Therefore, some attempts have been made to actively utilize such steelmaking slag.

For example, an aggregate containing steelmaking slag, a silica-containing substance having latent hydraulic properties, and a binder that hardens by a hydration reaction containing 50% or more of one or two kinds of silica-containing substances having pozzolanic reactivity. There is disclosed a hydrated and hardened body using a steelmaking slag characterized by containing (see Patent Document 1). In addition, as another example, a steel slag (including blast furnace slag) obtained by pulverizing or crushing all of the binder, fine aggregate, and coarse aggregate, and a slag block containing blast furnace slag and steelmaking slag as a binder. Is disclosed (see Patent Document 2). Further, after the converter slag is pulverized to 5 mm or less, magnetically separated and dried, and further pulverized to have a specific surface area of 3000 to 5000 cm ² / g, the converter slag fine powder has a moisture content of 1% or less. An example of blast furnace cement using converter slag obtained by mixing 10 to 30% by weight with blast furnace slag fine powder having a specific surface area of 3800 to 4200 cm ² / g is also disclosed (see Patent Document 3). In addition, a reinforced roadbed material is also disclosed in which 10 to 60% of dust collection dust generated in the converter slag crushing equipment is added and mixed with the blast furnace granulated slag in an absolutely dry weight ratio (see Patent Document 4).

  Here, the steelmaking slag means slag formed in any refining vessel used for melting molten steel, and high Cr molten steel including hot metal pretreatment slag, converter slag, electric furnace slag, etc. Smelting reduction furnace slag, stainless steel decarburization furnace slag, secondary refining slag (in the case of refining the molten steel from the converter or electric furnace to the ladle in the vacuum degassing tank or in the ladle Occur). Among these, the ladle refining slag as used in the present invention means that when molten steel is subjected to secondary refining such as desulfurization, deoxidation, decarburization, and degassing in ladle refining equipment such as VOD, RH, DH, and LF. It is generated slag.

JP-A-10-152364 JP-A-2-233539 JP-A-1-126246 JP 59-169966 A

  However, when the present inventor tried to prototype a slag hardened body using the converter slag and / or ladle smelting slag as a raw material using the above-described conventional technology, the following problems were revealed.

First, a slag hardened body (hereinafter simply referred to as a hardened body) was prototyped according to the methods disclosed in Patent Document 1, Patent Document 2 and Patent Document 3, but when some steelmaking slag was used, The compressive strength was less than 20 N / mm ² , and it did not withstand use as an alternative to cement and concrete. In addition, it has been proved that it cannot be used for applications such as hardened building blocks for construction, in which many cracks are generated and particularly strength and appearance are required. Furthermore, even when a steelmaking slag having a water immersion expansion ratio of 0.5% or less disclosed in Patent Document 1 was used, the compression strength of the cured body was less than 20 N / mm ² and cracking occurred.

  When this cause was investigated in detail, converter slag and / or ladle caused by dolomite, magnesia clinker, etc. added to slag in recent years for the purpose of protecting the refractory lining of converter and ladle. Although the MgO concentration of the smelting slag is high, if a converter slag and / or ladle smelting slag having a high MgO concentration is used, it is included in the converter slag and / or ladle smelting slag during water curing. It was found that the free MgO hydrated and expanded, and the cured product collapsed. In other words, unlike free CaO, free MgO does not easily become a stable hydroxide by aging treatment such as steam aging, and since the hydration reaction proceeds slowly, the strength expression of the cured product is delayed and collapsed. To do. Here, free MgO includes undehydrated MgO that remains unmelted during refining and crystallized MgO that is generated when slag in a molten state or a mixed state of a melt and a solid is solidified in the cooling process.

Therefore, the present inventor selected converter slag and / or ladle smelting slag containing almost no free MgO as steelmaking slag, and tried to produce a hardened body by a method similar to the technique described in the above publication. The compressive strength of No. ² was less than 20 N / mm ² , and many cracks could occur, so that it was not possible to withstand use as an alternative to cement and concrete. In addition, in the technique described in Patent Document 3, when a converter slag and / or ladle smelting slag having a specific surface area of 3000 cm ² / g or more, that is, a particle size of about 0.07 mm or less is included, almost no hardening occurs. . Furthermore, when an attempt was made to produce a cured product using the technique described in Patent Document 4, only a slag aggregated, and a cured product such as concrete could not be obtained.

  The present invention can solve problems such as insufficient strength, cracking, expansion due to free MgO, etc. of a slag hardened body obtained by using such converter slag and ladle refining slag as a part of raw materials at once. It aims at providing the manufacturing method of a slag hardening body.

  The inventor has intensively studied to achieve the above object, and the results have been embodied in the present invention.

That is, the present invention is a method for producing a slag hardened body by kneading a granular steel-making slag and a SiO ₂ -containing substance having latent hydraulic properties with water, wherein the unsteeled MgO is 1% by mass or less as the steel-making slag. In addition, the converter slag and / or ladle smelting slag having a crystallization MgO of 10% by mass or less are used as the SiO ₂ -containing substance having latent hydraulic property, and all the blended substances excluding water are used. The content ratio of the converter slag and / or ladle smelting slag having a particle size of 1.18 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 a manufacturing method of a hardening body.

Further, the present invention provides a method for producing a slag hardened body by kneading a granular steel-making slag and a SiO ₂ -containing substance having latent hydraulic properties with water, wherein the unsteeled MgO is 1% by mass or less as the steel-making slag. In addition, the converter slag and / or ladle smelting slag having a crystallized MgO content of 10% by mass or less is used as the SiO ₂ -containing material having latent hydraulic properties, and blast furnace slag fine powder and fly ash are used, and all water is removed. The content of the converter slag and / or ladle smelting slag having a particle size of 1.18 mm or less in the blended material is 10 to 90% by mass, the content of fine blast furnace slag powder is 3 to 36% by mass, and the content of fly ash 1.5-30 mass%, and the mass ratio of the fly ash content to the total content of blast furnace slag fine powder and fly ash is 0.1-0.75. It is a manufacturing method of a hardening body.

  In this case, the mass ratio of the content of converter slag and / or ladle smelting slag to the total content of blast furnace slag fine powder, fly ash, converter slag having a particle size of 1.8 mm or less and / or ladle smelting slag, More than 0.2, or one or two or more selected from oxides, hydroxides, sulfates, and chlorides of alkali metals and / or alkaline earth metals in addition to all the compounded substances except water It is good to add 0.2-20 mass% with respect to the total content of blast furnace slag fine powder and fly ash.

  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 the elution amounts of F, B, Se, and V from the raw material slag can be suppressed. This hardened body can be used as wave-dissipating blocks, fish reefs, seaweed building blocks, marine structures such as artificial stones, and other concrete substitutes, or as roadbed materials and earthen timber if crushed. Therefore, the present invention greatly contributes to the reuse of resources and the improvement of the environment.

It is a figure which shows the relationship between the un- hatched MgO density | concentration in converter slag, and the compressive strength of a hardening body. It is a figure which shows the relationship between the crystallization MgO density | concentration in converter slag, and the compressive strength of a hardening body.

  In the following, the embodiments of the present invention will be described in detail along with the process leading to the invention.

First, the inventor, in a method for producing a slag hardened body by kneading a granular steelmaking slag and a SiO ₂ -containing substance having latent hydraulic properties with water, in particular, 1% by mass of unfogged MgO is used as the steelmaking slag. In the following, granular converter slag and ladle refining slag having a crystallization MgO of 10% by mass or less were used. According to the methods disclosed in Patent Document 1 and Patent Document 2, when a cured product was prototyped using these slag as the main raw materials, the resulting cured product was reduced in strength and cracked. This is because it has been found that a hardened body having high strength and almost no cracks can be obtained if adjusted appropriately. In addition, the inventor adopted converter slag and ladle smelting slag having 1% by mass or less of uncontained MgO and 10% by mass or less of crystallized MgO as steelmaking slag as follows. Based on what I thought.

(1) as compared to other steel slag, since CaO / SiO ₂ is as high as 2 or more, containing many active high 2CaO · SiO ₂ in the slag. Therefore, it greatly contributes to the acceleration of the curing reaction, and can itself be a substitute for blast furnace slag fine powder and fly ash.

  (2) Compared to other steelmaking slag, it contains a lot of iron, so its specific gravity is high. Accordingly, 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 strength reduction and cracking due to hydration expansion of free MgO.
Then, based on the above idea, the inventor conducted research on the use of converter slag and ladle smelting slag containing free MgO to eliminate the strength reduction and cracking caused by hydration expansion of free MgO. In order to proceed, the experiment was repeated in order to find out the influence of the hydrated expansion of free MgO on the produced cured product.

  As a result, it has been found that the presence of undehydrated MgO among the free MgO has a great influence on the strength reduction and crack generation of the cured body. That is, FIG. 1 shows the relationship between the undehydrated MgO concentration in the converter slag and the compressive strength of the hardened body, but it is clear that the strength decreases when the undehydrated MgO concentration exceeds 1 mass%. It is. Moreover, as a result of continuing experiments, as shown in FIG. 2, it was found that the strength decreases when the crystallized MgO concentration exceeds 10 mass%.

Therefore, the inventor decided to make this knowledge one of the requirements of the present invention. That is, the strength due to the hydration expansion of free MgO of the cured product by making unconverted MgO contained in the converter slag and / or ladle smelting slag 1 mass% or less and crystallized MgO 10 mass%. This is to prevent the occurrence of cracks and cracks. The converter slag and ladle refining slag used in the present invention are preferably pre-aged to convert free CaO into stable Ca (OH) ₂ or CaCO ₃ . That is, it is preferable to use converter slag and ladle smelting slag having an expansion rate of 1.5% or less according to a water immersion expansion test of 80 ° C. × 6 hours / day × 10 days defined in JIS A 5015. This is because when the expansion coefficient exceeds 1.5%, the strength of the cured body is reduced and cracks are generated.

  However, as described above, free MgO does not easily become a stable hydroxide in the aging treatment, and the hydration reaction proceeds slowly. For example, 80 ° C. × 6 hours / day × 10 days according to JIS A 5015 of converter slag and ladle smelting slag containing 1% by mass of unoxidized MgO not containing free CaO and 10% by mass of crystallized MgO The expansion rate is about 1.0%, but the expansion continues without stopping for 10 days. Therefore, it is not sufficient to stabilize free CaO, and it is considered that the improvement in strength of the obtained cured product and suppression of occurrence of cracks are not satisfactory.

  Therefore, the inventor, as a countermeasure, when using such converter slag and ladle smelting slag having 1% by mass or less of undehydrated MgO and 10% by mass or less of crystallized MgO, The portion of 1.18 mm or less was conceived to have a content of 10 to 90% by mass in all the compounded substances excluding water. Of these slags, the portion that greatly contributes to the curing reaction was investigated in detail, and those having a particle size of 1.18 mm or less have particularly good reactivity, the strength of the obtained cured body is high, and cracks are remarkably generated. This is because it has been found to be smaller. Moreover, it turned out that the elution of F, B, Se, and V from the slag which becomes an environmental problem can be suppressed by using these slag as a raw material of a hardening body. The inventor then found that the particle size of 1.18 mm or less contained in the converter slag and ladle smelting slag having 1 mass% or less of undehydrated MgO and 10 mass% or less of crystallized MgO. Regarding the content of the part in all the compounded substances, the reason will be described later, but it was decided to add a limitation of 10 to 90% by mass to the requirement of the present invention. In addition, this means that the unsaturated MgO used in the blending is 1% by mass or less and the converter slag and ladle refining slag having a crystallized MgO of 10% by mass or less have a larger particle size than this. Does not preclude inclusion. The converter slag and ladle smelting slag having a large particle size of unaggregated MgO of 1% by mass or less and a crystallized MgO of 10% by mass or less only means that it was not easily pulverized during the pulverization process. This is because the binder contributes to the production of a cured body. Here, the particle size in the present invention is a numerical value determined by sieving, and may be measured by a method defined in JIS A 1102.

Next, a SiO ₂ -containing material having latent hydraulic properties to be reacted with converter slag and / or ladle smelting slag having 1% by mass or less of undehydrated MgO and 10% by mass or less of crystallized MgO was 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 pulverizing blast furnace granulated slag, and preferably has a particle size of about 0.1 mm or less, that is, a specific surface area of about 3000 cm ² / g or more by the brane method. Further, it is more preferable to use fine powder of blast furnace slag of about 4000 cm ² / g or more because the activity becomes higher.

  The proper 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, but the proper blending amount is 5 to 40% by mass. Then, this limitation is added to the above two requirements to complete the present invention.

The reason for limiting the amount of blast furnace slag fine powder used is as follows. That is, the content of unsaturated MgO having a particle size of 1.18 mm or less and 1% by mass or less and the content of converter slag and / or ladle smelting slag having a crystallized MgO of 10% by mass or less is less than 10% by mass, or When the content of the blast furnace slag fine powder exceeds 40% by mass, the supply of alkali (or alkaline earth) ions that are relatively cured by reacting with SiO ₂ tends to be insufficient, and the strength of the resulting cured product is reduced. It is. On the other hand, the content of unsaturated MgO having a particle size of 1.18 mm or less is 1% by mass or less and the content of converter slag and / or ladle smelting slag having a crystallized MgO of 10% by mass or more exceeds 90% by mass, or If the content of the blast furnace slag fine powder is less than 5% by mass, SiO ₂ for fixing components such as CaO and MgO having the hydration expansibility of the converter slag and ladle smelting slag becomes scarcely obtained. This is because the cured body is expanded and pulverized in the process of curing the cured body, and the strength is significantly reduced.

As described above, the method for producing a slag cured body according to the present invention is a method for producing a cured slag body in which powdered steelmaking slag and a SiO ₂ -containing substance having latent hydraulic properties are kneaded with water and cured. In particular, as the steelmaking slag, granular converter slag and / or ladle smelting slag in which uncontained MgO is 1% by mass or less and crystallization MgO is 10% by mass or less are used, and the amount of use Kneading with water and curing so that the amount of fine powder of blast furnace to be blended is also appropriate. Thereby, free MgO in converter slag and ladle refining slag does not cause hydration expansion during curing. As a result, the obtained slag cured body has not only high strength immediately after production, but also does not generate cracks. Moreover, this hardening body can reduce the shrinkage | contraction by drying and can prevent a crack as a result.

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

  This fly ash is ash generated during coal combustion, and not only JIS standard products but also non-standard products can be used. However, it is preferable to use JIS A 6201 standard type I or type II because they are fine powders and are therefore more active. By using this as a partial substitute for blast furnace slag fine powder, the reactivity with converter slag and ladle smelting slag with 1% by mass or less of undehydrated MgO and 10% by mass or less of crystallized MgO is achieved. Further improvement is possible, and it is possible to suppress the occurrence of cracks in the cured body and to improve the strength after long-term curing. Furthermore, the generation of cracks due to drying shrinkage of the cured body can also be prevented.

  When this fly ash is mixed with blast furnace slag fine powder and used, the proper content of the compounded materials is 1% by mass or less of un-enriched MgO, 10% by mass or less of crystallized MgO and a particle size of 1.18 mm. The following converter slag and / or ladle refining slag is preferably 10 to 90 mass%, blast furnace slag fine powder is 3-36 mass%, and fly ash is 1.5 to 30 mass%. In this case, the mass ratio of the fly ash content to the total content of the blast furnace slag fine powder and fly ash must be 0.1 to 0.75. In particular, the effect is remarkable when the content is 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 fly ash is 0.1 or more. . However, fly ash tends to be inferior in curability at room temperature to blast furnace slag fine powder, and the fly ash content exceeds 30% by mass, or fly ash with respect to the total content of blast furnace slag fine powder and fly ash. If the mass ratio of the content exceeds 0.75, curing of the entire cured body is delayed, which is not preferable. Therefore, in this embodiment of the present invention, 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 fly ash is 0.00. 1 to 0.75.

Furthermore, further research has shown that blast furnace slag fine powder, fly ash and un-dehydrated MgO are 1% by mass or less, crystallized MgO is 10% by mass and grain size is 1.18mm or less, and / or ladle refining. The mass ratio of the content of converter slag and / or ladle smelting slag containing 1% by mass or less of undehydrated MgO and 10% by mass or less of crystallized MgO with respect to the total content of slag is more than 0.2. I found that was good. Therefore, the present invention, which is also a requirement, has been completed. By limiting to such a range, the alkali (or alkaline earth) supplied from converter slag or ladle refining slag having 1% by mass or less of undehydrated MgO and 10% by mass or less of crystallized MgO. This is because the quantitative balance between ions and reactive SiO ₂ in the SiO ₂ -containing substance having latent hydraulic properties becomes more appropriate, and the effect of preventing cracks of the resulting cured body is enhanced.

  According to the present invention including the other embodiments described above, a remarkable effect can be obtained in improving the strength of the cured body and reducing the occurrence of cracks. In addition, the present invention further includes oxides of alkali metals and / or alkaline earth metals, You may add the requirement to add 0.2-20 mass% of 1 type, or 2 or more types chosen from hydroxide, sulfate, and chloride with respect to the total content of blast furnace slag fine powder and fly ash. .

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, curing of the cured product is accelerated. This is because the time required for curing can be shortened. However, even if added over 20% by mass, the effect is saturated, so the upper limit is made 20% by mass. Preferred examples of such a substance include Ca (OH) ₂ , NaOH, CaO, CaSO ₄ .2H ₂ O, and CaCl ₂ .

Below, as a steelmaking slag, unconverted MgO whose composition is shown in Table 1 is 1% by mass or less, and powdered converter slag and / or ladle smelting slag having a crystallized MgO of 10% by mass or less are used. Examples and comparative examples will be described. In addition, the blast furnace slag fine powder used the product whose specific surface area by a brane method is about 4000 cm < ² > / g, and fly ash used the II class product of JISA6201.
Example 1
Powdered converter slag and / or ladle smelting slag, ground granulated blast furnace slag, Ca (OH), containing 1% by mass or less of undehydrated MgO crushed as a blending raw material and 10% by mass or less of crystallized MgO ₂ was kneaded with water, poured into a mold, and 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. The strength of the resulting cured body after 20 days of water curing at 20 ° C., surface dry specific gravity, number of surface cracks after air curing at 20 ° C., strength after 91 days of water curing at 20 ° C., 28 days at 20 ° C. Table 3 shows the elution amounts of F, B, Se, and V measured by the Environmental Agency Notification No. 46 method after air curing.

(Example 2)
Granulated converter slag and / or ladle smelting slag, ground blast furnace slag fine powder, fly ash, and Ca containing 1% by mass or less of undehydrated MgO crushed as a blending raw material and 10% by mass or less of crystallized MgO (OH) ₂ was kneaded with water, poured into a mold, and cured in water at 20 ° C. to produce a cured product. Table 4 shows the content and ratio of each raw material in the blend and the amount of kneaded water added. The strength of the obtained cured body after 20 days of water curing at 20 ° C., surface dry specific gravity, the number of surface cracks after air curing at 20 ° C. for 28 days, strength after 91 days of water curing at 20 ° C., and the atmosphere for 28 days at 20 ° C. Table 5 collectively shows the elution amounts of F, B, Se, and V measured by the Environmental Agency Notification No. 46 after the birth.

(Example 3)
About powdered converter slag and / or ladle smelting slag, ground granulated blast furnace slag, which is 1 mass% or less of pulverized un-contaminated MgO as a blending raw material and 10 mass% or less Added fly ash to them, and Ca (OH) _{2 and} other additives were kneaded with water and poured into a mold, which was cured in water at 20 ° C. to produce a cured product. Tables 6 and 7 show the content and ratio of each raw material in the blend and the amount of kneading water added. The strength of the obtained cured body after 20 days of water curing at 20 ° C, surface dry specific gravity, number of surface cracks after air curing at 20 ° C, strength after 91 days of water curing at 20 ° C, 28 days at 20 ° C The elution amounts of F, B, Se, and V measured by the Environmental Agency Notification No. 46 method after air curing are collectively shown in Tables 8 and 9.

(Comparative example)
For powdered converter slag and / or ladle smelting slag, blast furnace slag fine powder, which is 1% by mass or less of undecontaminated MgO crushed as a blending raw material and 10% by mass of crystallized MgO, To these, fly ash and Ca (OH) ₂ were kneaded with water under a condition with a content outside the scope of the present invention, poured into a mold, and cured in water at 20 ° C. to produce a cured product. Table 10 shows the content and ratio of each raw material in the blend and the amount of kneading water added. The strength of the obtained cured body after 20 days of water curing at 20 ° C, surface dry specific gravity, number of surface cracks after air curing at 20 ° C, strength after 91 days of water curing at 20 ° C, 28 days at 20 ° C Table 11 shows the elution amounts of F, B, Se, and V measured by the Environmental Agency Notification No. 46 after air curing.

  In addition, the number which can be confirmed visually was described in the surface crack number of the hardening body in a present Example and a comparative example.

The results obtained in the above Examples and Comparative Examples can be summarized as follows by referring to the respective tables described above. In other words, among the granular converter slag and / or ladle smelting slag having an undehydrated MgO content of 1% by mass or less and a crystallized MgO content of 10% by mass or less, the inclusion of particles having a particle size of 1.18 mm or less In the comparative example in which the rate does not satisfy the conditions of the present invention, the surface cracks of the cured product after curing for 28 days are 3 / cm ² , the wear resistance is poor, and the cured product is cracked or chipped during handling. did. However, in the examples of the present invention, all the cured bodies had cracks of 0.5 / cm ² or less, the cracks were extremely small, and there was no problem of wear resistance or cracking or chipping during handling. In particular, blast furnace slag fine powder, fly ash, and granular converter slag and / or ladle in which unaggregated MgO having a particle size of 0.425 mm or less is 1% by mass or less and crystallization MgO is 10% by mass or less. The ratio of the content of the converter slag and / or ladle refining slag to the total content of the refining slag (ratio indicated by C in the table) is 1-1, 1- In 3, 1-6, 1-7, 1-9, 1-22, the number of cracks of the cured body is further reduced to 0.4 / cm ² or less.

Also, blast furnace slag fine powder, fly ash, and granular converter slag and / or ladle in which unaggregated MgO having a particle size of 0.1 mm or less is 1% by mass or less and crystallization MgO is 10% by mass or less. The ratio of the content of the converter slag and / or ladle smelting slag to the total content of the refining slag (ratio indicated by D in the table) is 1-10 to 1- In No. 22, the number of cracks of the cured body is further reduced to 0.3 / cm ² or less.

Furthermore, in each example of Example 2 in which an appropriate amount of fly ash is blended in addition to the blast furnace slag fine powder, the number of cracks in the cured product can be further reduced. In addition, in each example of Example 3 to which various additives (Ca (OH) ₂ , NaOH, CaSO ₄ · 2H ₂ O, etc.) were added, the strength of the cured product was improved and the cracks were reduced. In addition, the elution amounts of F, B, Se, and V could be suppressed in each example. Comparative Example 4 was produced with the blending amount and particle size corresponding to the example of Patent Document 2, but the compression strength of the cured body was low, and the effect of suppressing the elution amount of F, B, Se, and V was almost the same. I couldn't see it.

Claims (4)

In a method for producing a slag hardened body by kneading a granular steel-making slag and a SiO ₂ -containing substance having latent hydraulic properties with water,
As the steelmaking slag, converter slag and / or ladle smelting slag having 1% by mass or less of undehydrated MgO and 10% by mass or less of crystallized MgO is used as the blast furnace slag as the SiO ₂ -containing material having the latent hydraulic property. While using fine powder, the content rate of the converter slag and / or ladle smelting slag having a particle size of 1.18 mm or less in all the compounded substances excluding water is 10 to 90% by mass, and the content rate of blast furnace slag fine powder. The manufacturing method of the slag hardening body characterized by setting it as 9-40 mass%. In a method for producing a slag hardened body by kneading a granular steel-making slag and a SiO ₂ -containing substance having latent hydraulic properties with water,
As the steelmaking slag, converter slag and / or ladle smelting slag having 1% by mass or less of undecontaminated MgO and 10% by mass or less of crystallized MgO is used as a blast furnace slag fine material as a SiO ₂ -containing substance having latent hydraulic properties. While using powder and fly ash, the content of the converter slag and / or ladle smelting slag having a particle size of 1.18 mm or less in all the compounded substances excluding water is 10 to 90% by mass, and the content of blast furnace slag fine powder The rate is 3 to 36% by 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 fly ash is 0.1 to 0. .75, A method for producing a cured slag product.   The mass ratio of the content of the converter slag and / or ladle smelting slag to the total content of blast furnace slag fine powder, fly ash, and converter slag and / or ladle smelting slag having a particle size of 1.18 mm or less is 0. The manufacturing method of the slag hardening body of Claim 1 or 2 made more than two. In addition to one or more selected from oxides, hydroxides, sulfates and chlorides of alkali metals and / or alkaline earth metals, blast furnace slag fine powder and fry It adds 0.2-20 mass% with respect to the total content of ash, The manufacturing method of the slag hardening body in any one of Claims 1-3 characterized by the above-mentioned.

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