JP5095960B2 - Method for producing metal aluminum-containing slag and / or ash for hardened cement and method for producing hardened cement - Google Patents

Description

  The present invention is a metal for a cemented cured product that can effectively suppress the expansion of the cured product produced when a cemented cured product such as concrete or mortar is produced using metal aluminum-containing slag and / or ash. The present invention relates to a method for producing aluminum-containing slag and / or ash, and a method for producing a hardened cement material.

Waste incineration ash, RDF (Refuse Derived Fuel) ash, waste incineration ash molten slag, steelmaking slag and other incineration ash and slag can be reused without being discarded. It has been conventionally used as an aggregate, an admixture, and the like. In particular, the use of waste incineration ash that is disposed of in large quantities as a result of social life and the slag obtained by processing it as a substitute for sand as an aggregate of cement-hardened material suffers from the depletion of high-quality aggregates. It is extremely beneficial for the construction industry.
These incinerated ash and slag may remain with metal aluminum depending on the combustion or melting method, and further the conditions thereof. When such incinerated ash and slag are used as aggregates and admixtures for cement hardened materials, especially when slag containing metal aluminum is used, the metal is corroded in the alkaline environment of the hardened cement products such as rust. Is generated. In this process, hydrogen gas is generated and expands in a fresh state of the hardened cement material, which causes problems such as abnormal expansion of the hardened material, a decrease in strength, and a decrease in durability.
It is very difficult technically and costly to remove such metal aluminum from incineration ash and slag. Therefore, in order to suppress such expansion, these are usually blended with a cement composition together with natural aggregates or the like so as to keep the blending ratio below a certain level. For example, when a slag aggregate containing aluminum is blended in a cement composition, the ratio of the aluminum-containing slag to the aggregate as a whole is usually limited to less than 50% by weight in order to sufficiently suppress expansion. This is an obstacle to efficiently reusing a large amount of incineration ash and slag.

Therefore, Patent Literature 1 proposes an expansion inhibitor for a cement composition containing an alkali metal salt, and a cement composition containing the inhibitor, and Patent Literature 2 discloses an alkali metal salt and an alkaline earth metal. An expansion inhibitor for a cement composition containing a salt of the above, and a cement composition containing the inhibitor have been proposed.
These inhibitors can effectively and easily suppress abnormal expansion of a cured product in a cement composition containing aluminum-containing slag and the like. However, since an inhibitor containing an alkali metal salt or a salt of the alkali earth metal and the salt is used in the cement composition itself, in order to obtain a desired effect, these metals in the cement composition are used. It is necessary to increase the amount of salt added. In addition, when the amount of the inhibitor is decreased, excessive mixing is performed so that the inhibitor sufficiently contacts the aluminum-containing slag and the like in the cement composition. Needed and not realistic.
JP 2001-39749 A JP 2002-326853 A

  An object of the present invention is to effectively and efficiently suppress the expansion of a cured product produced when a cement cured product such as concrete or mortar is produced using metal aluminum-containing slag and / or ash. An object of the present invention is to provide a method for producing metal aluminum-containing slag and / or ash for hardened cement and a method for producing a hardened cement using such slag and / or ash.

ADVANTAGE OF THE INVENTION According to this invention, it is a manufacturing method of metal aluminum containing slag and / or ash used for manufacture of this cement hardened | cured material which can suppress the expansion | swelling at the time of hardening of cement hardened | cured material, Comprising: Metal aluminum containing slag and / or ash a step of preparing a (a), the metallic aluminum-containing slag and / or ash, saw including a step (B) contacting the aqueous solution (s) containing an alkali metal salt and / or alkaline earth metal salts, the alkali The metal is selected from the group consisting of lithium, sodium, potassium and mixtures thereof, the alkaline earth metal is selected from the group consisting of calcium, magnesium and mixtures thereof, and the salt is nitrate, nitrite, silicate, phosphate and metallic aluminum-containing slag and / or ash cement cured product characterized by being selected from the group consisting of mixtures Manufacturing method is provided.
Further, according to the present invention, the above-mentioned step (A), the above-mentioned step (B), and the cement composition containing metal aluminum-containing slag and / or ash, cement and water obtained in step (B) are mixed and cured. And a step (C) of providing a cemented cured product characterized by comprising:

Since the method for producing metal aluminum-containing slag and / or ash for the cement composition of the present invention includes the steps (A) and (B), the obtained slag and / or ash is used for the production of a cement cured product. This effectively and efficiently suppresses the expansion of the cured cement resulting from the metal aluminum. Therefore, although the obtained slag and ash contain metallic aluminum, they can be used as they are for the production of a hardened cement.
Since the method for producing a cured cement according to the present invention includes the above steps (A) to (C), it is effective and efficient even when the amount of an inhibitor that suppresses the expansion of the conventional cured cement is reduced. In particular, the expansion can be suppressed.

Hereinafter, the present invention will be described in more detail.
The manufacturing method of the metal aluminum containing slag and / or ash of this invention, and the manufacturing method of cement hardened | cured material include the process (A) of preparing metal aluminum containing slag and / or ash.
In the step (A), examples of the slag and / or ash containing metal aluminum include metal slag and various slags and ash that can expand when mixed and cemented in a cement composition. Can do.
Examples of the slag or ash include refuse incineration ash, RDF ash, waste incineration ash molten slag, steelmaking slag, nonferrous metal slag such as ferronickel slag and copper slag, or a mixture of two or more thereof.

Examples of the waste incineration ash include combustible general waste or industrial waste.
Garbage incineration ash melting slag is a solidified product obtained by incineration and melting waste. For example, waste generated from social life is incinerated, and the generated ash is melted by heat treatment at a temperature of about 1200 to 1600 ° C. using a melting furnace such as a burner type surface melting furnace or electric furnace or a coke bed, Alternatively, it can be obtained by cooling by simply leaving it at room temperature. It can also be obtained by simultaneously performing the incineration and melting steps.
Steelmaking slag and non-ferrous metal slag include slag produced as a by-product in processes such as steelmaking, non-ferrous metal refining, nickel refining, respectively.
The particle size of the slag containing metallic aluminum is not particularly limited, and various particle sizes can be obtained depending on the process of generation. For example, in the case of waste incineration ash molten slag, a relatively small particle size is obtained when the ash melt is cooled at a rapid rate, and a relatively small particle size is obtained when the cooling rate is slow. A big one is obtained.

The method for producing a metal aluminum-containing slag and / or ash and the method for producing a cement hardened product of the present invention includes an aqueous solution (s) containing an alkali metal salt and / or an alkaline earth metal salt in the metal aluminum-containing slag and / or ash. ) Is contacted.
In the step (B), the alkali metal salt and / or alkaline earth metal salt is prepared by using the metal aluminum-containing slag and / or ash prepared in the step (A) for the production of a cement hardened product. It is a component that can suppress the expansion of the hardened cement product.
Alkali metals are lithium and sodium, potassium or more of these. Further, alkaline earth metals are calcium and / or magnesium.
Alkali metal salts and / or alkaline earth metal salts, nitrates, nitrites, silicates, and phosphates, especially nitrates, or mixtures of nitrates and nitrites are preferably exemplified.
These ratios when the alkali metal salt and the alkaline earth metal salt are used in combination are the ratio of the alkali metal and the alkaline earth metal, and the alkaline earth metal is 1 to 10 moles per mole of the alkali metal. It is preferable that

  In the step (B), the aqueous solution (s) is not particularly limited as long as it contains an alkali metal salt and / or an alkaline earth metal salt, but is not limited to an alkali metal salt and / or an alkaline earth metal salt. The concentration is usually 50% by weight or less, preferably 0.1 to 10% by weight, particularly preferably 0.3 to 5% by weight. When the concentration of the alkali metal salt and / or alkaline earth metal salt is low, it is necessary to increase the contact amount and the contact time with the slag and / or ash containing metal aluminum, while the concentration is high. Although the desired effect of the present invention is achieved, when the obtained slag or ash is used in a cement composition, the setting of cement may be accelerated.

In the step (B), the amount of contact of the aqueous solution (s) with the metal aluminum-containing slag and / or ash is appropriately determined according to the content of metal aluminum in the slag to be treated and / or the ash and the form thereof. If necessary, a sample test can be performed to determine the contact amount and the concentration. Here, since the alkali metal salt and / or alkaline earth metal salt that suppresses the expansion of the cement hardened product is used in the form of an aqueous solution, the salt is directly brought into contact with slag or ash. In addition, the contact amount of the alkaline earth metal salt can be sufficiently reduced as compared with the conventional addition and mixing to the cement composition, the contact conditions can be relaxed, and the complication of the process can be suppressed. be able to.
Determination of the concentration and the contact amount of the aqueous solution (s) is, for example, when the obtained metal aluminum-containing slag and / or ash is used for the production of a hardened cement, the expansion coefficient of the hardened cement is determined according to JIS TR A0016. It is preferable that the value measured in accordance with “Appendix 1“ Method for testing expansion rate of mortar using melt-solidified fine aggregate for concrete ”” is 2% or less.

  The contact of the aqueous solution (s) with the metallic aluminum-containing slag and / or ash is, for example, (1) a method of using the aqueous solution (s) in place of the cooling water for water cooling used in the production of slag or ash. , (2) a method of using the aqueous solution (s) in place of the spray water used when adjusting the particle size of the slag, and (3) mixing after spraying the aqueous solution (s) on slag or ash (4) A method of immersing slag or ash in the aqueous solution (s) and then taking it out and drying it. (5) A method of adding the aqueous solution (s) to the slag or ash and mixing them. The slag and ash after contact with the aqueous solution (s) can be usually dried or forcedly dried for about several minutes to 24 hours to obtain desired slag or ash.

The method for producing a hardened cement product of the present invention includes a step (C) of mixing and hardening the cement composition containing metal aluminum-containing slag and / or ash, cement and water obtained in the step (B).
In the step (C), the mixing ratio of the slag and / or ash is not particularly limited, but is usually 10 to 100% by mass based on the total amount of the aggregate and the admixture in the cement composition, and the cement composition is cured. When it is made, it can mix | blend so that it may become a ratio of about 50-500g normally per 1000g of hardened | cured material.
Moreover, the mixing | blending ratio of the said slag and / or ash can be normally mix | blended so that it may become about 80-300 mass parts per 100 mass parts of cement.

In the cement composition, in addition to the slag and / or ash, cement, and water, other ingredients blended in a normal cement composition such as coarse aggregate, fine aggregate, admixture, and admixture are included. A desired cement cured product can be produced by kneading with water at the time of curing and curing by a known method.
The type and proportion of cement basically has the desired effect according to the proportion of metallic aluminum in slag and / or ash, the proportion of other coarse aggregates, fine aggregates, admixtures, etc. It can adjust suitably according to the use of the cement hardened material obtained so that it may be obtained.

Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these.
Examples 1 to 5 and Comparative Example 1
Calcium nitrate aqueous solutions having concentrations shown in Table 1 were prepared, and molten slag containing metal aluminum (burner type surface molten slag) was immersed in each aqueous solution for 3 hours. Next, the immersion-treated slag was dried in an oven at 40 ° C. for 24 hours to prepare a target metal aluminum-containing slag.
Using each of the prepared metal aluminum-containing slags, mortars were prepared according to JIS TR A0016 Annex 1 “Method of testing mortar expansion rate using molten solidified fine aggregate for concrete”, and the expansion rate was measured. . In addition, as Comparative Example 1, the expansion coefficient was measured in the same manner using a metal aluminum-containing molten slag that was not subjected to immersion treatment with an aqueous calcium nitrate solution. The results are shown in Table 1.
Further, the compressive strength at the age of 1 day, 7 days, 14 days and 28 days of the mortars of Example 4 and Comparative Example 1 prepared above was measured according to JIS A 1108. The results are shown in Table 2.

Examples 6-12
A calcium nitrate aqueous solution having a concentration shown in Table 3 was prepared. Next, each aqueous solution in a ratio shown in Table 3 was added to 100 parts by weight of molten slag containing metallic aluminum (burner type surface molten slag), and mixed and stirred to prepare a target metallic aluminum-containing slag.
Using each of the prepared metal aluminum-containing slags, mortars were prepared according to JIS TR A0016 Annex 1 “Method of testing mortar expansion rate using molten solidified fine aggregate for concrete”, and the expansion rate was measured. . The results are shown in Table 3.

Reference Examples 1-6
Aqueous solutions each having a weight ratio of calcium nitrite: calcium nitrate of 1: 1 shown in Table 4 were prepared. Next, as a hypothetical slag, each aqueous solution in the ratio shown in Table 4 was added to 100 parts by weight of a mixture of 450 g of sand (from Oikawa-made river sand) and 2.25 g of fine aluminum powder (manufactured by Wako Pure Chemical Industries), and mixed and stirred. Thus, a target metallic aluminum-containing virtual slag was prepared.
Using the total amount of each metal aluminum-containing virtual slag, 400 g of cement, and 200 g of water containing 2 g of high-performance water-reducing material, JIS TR A0016 Annex 1 “Mortar of mortar using molten solidified fine aggregate for concrete” Mortar was prepared according to “Expansion coefficient test method”, and the expansion coefficient was measured. The results are shown in Table 4.

Reference Comparative Example 1
Supplied with JIS TR A0016 using 450g of sand (Oikawa produced river sand) and 2.25g of fine aluminum powder (manufactured by Wako Pure Chemical), 400g of cement and 200g of water containing 2g of high-performance water reducing material as virtual slag Mortar was prepared in accordance with “Method for testing expansion rate of mortar using melt-solidified fine aggregate for concrete” in the book 1, and the expansion rate was measured. The results are shown in Table 4.

Reference Comparative Examples 2 and 3
2. Mixing 2.25 g of calcium nitrite: calcium nitrate in a weight ratio of 1: 1 (Reference Comparative Example 2) or 4.50 g of the mixture (Reference Comparative Example 3) and 200 g of water containing 2 g of a high performance water reducing material. After that, it was added to a mixture of 450 g of sand (Oikawa-made river sand) as hypothetical slag and 2.25 g of fine aluminum powder (manufactured by Wako Pure Chemical Industries, Ltd.) and 400 g of cement, and “Melting for concrete” in JIS TR A0016 Annex 1 Mortar was prepared according to “Method for testing expansion rate of mortar using solidified fine aggregate”, and the expansion rate was measured. The results are shown in Table 4.
In addition, the usage-amount of the mixture of the calcium nitrite: calcium nitrate of the reference comparative example 2 of 1: 1 by weight ratio is the same amount as the reference examples 1 and 2, and the calcium nitrite: calcium nitrate of the reference comparative example 3 is the same amount. The amount of the mixture used at a weight ratio of 1: 1 is the same as that of Reference Example 3, and the amount of the mixture of calcium nitrite and calcium nitrate of Reference Examples 4 to 6 used at a weight ratio of 1: 1 is the reference comparison. This is an example used in a smaller proportion than Example 2.

  From the results shown in Table 4, in Reference Comparative Examples 2 and 3 in which a mixture of calcium nitrite: calcium nitrate in a weight ratio of 1: 1 was added to the mixture of virtual slag and cement, the amount used was the same. It can be seen that the expansion rate of the mortar is higher than those of Reference Examples 1 and 2 or Reference Example 3 based on the method of the invention. Further, from Reference Examples 4 to 5, it was found that even when the amount of a mixture of calcium nitrite: calcium nitrate of 1: 1 by weight ratio was reduced, the expansion rate could be reduced to 2% or less of the preferred range.

Claims (4)

A method for producing metal aluminum-containing slag and / or ash, which can be used to produce a hardened cement product, capable of suppressing expansion of the hardened cement product.
A step (A) of preparing metallic aluminum-containing slag and / or ash; and
The metallic aluminum-containing slag and / or ash, saw including a step (B) contacting the aqueous solution (s) containing an alkali metal salt and / or alkaline earth metal salt, the alkali metal is lithium, sodium, potassium and their The alkaline earth metal is selected from the group consisting of calcium, magnesium and mixtures thereof, and the salt is composed of nitrate, nitrite, silicate, phosphate and mixtures thereof. A method for producing metal aluminum-containing slag and / or ash for hardened cement, which is selected from the group . A step (A) of preparing metallic aluminum-containing slag and / or ash; and
Contacting the aqueous solution (s) containing the alkali metal salt and / or alkaline earth metal salt with the metal aluminum-containing slag and / or ash, and (B),
Step (B) obtained in metallic aluminum-containing slag and / or ash, saw including a step (C) to be mixed and cured cement composition comprising a cement and water, wherein the alkali metal is lithium, sodium, potassium and their The alkaline earth metal is selected from the group consisting of calcium, magnesium and mixtures thereof, and the salt is composed of nitrate, nitrite, silicate, phosphate and mixtures thereof. A method for producing a hardened cement product, characterized in that it is selected from the group . The production according to claim 1 or 2, wherein the concentration of the alkali metal salt and / or alkaline earth metal salt in the aqueous solution (s) containing the alkali metal salt and / or alkaline earth metal salt is 0.1 to 50% by weight. Method.   The metal aluminum-containing slag and / or ash is selected from the group consisting of refuse incineration ash, RDF ash, refuse incineration ash molten slag, steelmaking slag, nonferrous metal slag, and mixtures thereof. The manufacturing method of description.