JPS59227760A - Manufacture of hardened body from such as blast furnace slag - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a method for producing a hardened material such as blast furnace slag.

Currently, approximately 8,000 blast furnace slags are used annually in the steel industry.
Million tons are also produced as a by-product. Blast furnace slag, which is produced in large quantities in this way, has latent hydraulic properties, so conventionally, Portland cement, lime, Sencola, etc. are added as a stimulant, and the slag is hardened and used as a building material. In this case, the setting time was long and the resulting blast furnace slag building material had the disadvantage of having low initial strength.

Therefore, as a result of intensive research aimed at providing a blast furnace slag building material that improves the above-mentioned drawbacks, the present inventors have previously treated blast furnace slag, which has latent hydraulic properties, with sulfuric acid.
It was discovered that the above purpose could be achieved by converting a part of it into a soluble state to increase its reactivity and then reacting with lime to harden it.Based on this knowledge, blast furnace slag was treated with sulfuric acid. with sulfuric acid treated blast furnace slag slurry,
Next, slaked lime was added to this sulfuric acid-treated blast furnace slag slurry to prepare 12 pl of slurry pi (pi), and a method for manufacturing a hardened material such as blast furnace slag was previously completed, which is characterized by forming and hardening the slurry.

However, in the case of the above manufacturing method, although the curing time after molding can be adjusted to some extent by changing the amounts of sulfuric acid and slaked lime, it is impossible to shorten it to the extent that it can be demolded in a short time. Ta.

The present inventors have conducted various studies with the aim of shortening the solidification and hardening time of the molded product without degrading the physical properties of the product, such as strength, in the above-mentioned method for producing a hardened body of blast furnace slag. Addition of aluminum sulfate, aluminum hydroxide, Portland cement, etc. had no effect, but by adding aluminate, especially when added in a specific amount to blast furnace slag, setting and hardening time can be significantly shortened. I found out. Furthermore, it has been found that similar effects can be obtained when a hardened body is similarly obtained using fly ash instead of blast furnace slag.

That is, the present invention was made based on the above knowledge, and involves treating blast furnace slag or fly ash with sulfuric acid, and then adding slaked lime or quicklime to the slurry obtained by this sulfuric acid treatment to adjust the pH of the slurry to 12 or higher. The present invention also provides a method for producing a hardened material such as blast furnace slag, which comprises adding and kneading an aluminate to the material, forming and hardening the material.

The manufacturing method of the present invention will be explained in detail below based on an embodiment in which blast furnace slag is used.

The blast furnace slag used in the present invention has latent hydraulic properties and is discharged in large quantities in the steel industry, and is not particularly limited in its type.

In carrying out the present invention, first, in the first step, a sulfuric acid solution is added to the blast furnace slag, and the slag is treated with sulfuric acid to increase the reactivity of the slag, thereby obtaining a sulfuric acid-treated blast furnace slag slurry. When blast furnace slag is treated with sulfuric acid, a portion of it changes into a soluble state, increasing its reactivity.

The concentration of the sulfuric acid solution is preferably 5 to 20%, more preferably 5 to 11%, and the amount added is within the above concentration range of 150 to 100 parts (parts by weight, same hereinafter) of blast furnace slag. 250 parts is preferred. Further, the time for the sulfuric acid treatment of the blast furnace slag is preferably until the reaction between the blast furnace slag and sulfuric acid reaches equilibrium, and usually 1 to 3 hours is appropriate.

Next, in the second step, slaked lime or quicklime is added to the sulfuric acid-treated blast furnace slag slurry obtained in the first step.
Add 0 to 60 parts to make the pn of the slurry 12 or more, preferably 12.5 or more. In addition, 5 to 40 parts of aluminate, preferably 5 to 20 parts, per 100 parts of blast furnace slag.
Add part.

The reason why the pH of the lime-added slurry is set to 12 or more is that in the third step described later, if pl+ is less than 12, the slurry will not harden, and if the pH is 12 or more, especially 12.5 or more, it will not be compatible with the addition of aluminate. This is because it cures suitably in a short time. This is presumed to be because when the pH is 12 or higher, high sulfate type calcium sulfoaluminate hydrate is produced in the slurry, and this product contributes to the hardening of the slurry. As the aluminate, calcium aluminate and sodium aluminate are suitable, and alumina cement containing sodium aluminate as a main component is also used. If the amount of aluminate added is less than 5 parts, the addition effect, that is, the effect of promoting setting, will not be sufficient, and if sodium aluminate or alumina cement is used,
It is undesirable to exceed 100% because the strength of the product deteriorates. In order to accelerate the setting time and improve the strength of the product, the amount of sodium aluminate added is preferably 5 to 20 parts.

Even if the same aluminum compound is used, such as aluminum hydroxide or aluminum sulfate, the object of the present invention will not be achieved.

Further, by changing the amount of aluminate added within the above range, the setting time can be accelerated depending on the amount added, so the setting time can be adjusted depending on the purpose.

In the third step, after kneading the slurry obtained in the second step, the blast furnace slag in the mixed material is treated with sulfuric acid in the first step to increase its reactivity, and aluminate is added. Because of this, the blast furnace slag and lime quickly react with the aluminate and harden to the extent that it can be demolded in about one hour. After curing, the mold is demolded, and the hardened blast furnace slag according to the present invention is obtained by natural curing or, if necessary, steam curing.

In addition, although the case where blast-furnace slag was used was demonstrated above, the hardened body of fly ash can be obtained similarly when blast-furnace slag is replaced with fly ash. In addition, in the present invention, waste paper treated with sulfuric acid or M
By mixing paper sludge into blast furnace slag slurry and making it composite with blast furnace slag, it is possible to reduce the weight of the hardened blast furnace slag body according to the present invention to a bulk specific gravity of about 0.6 to 0.8. This hardened blast furnace slag mixed with waste paper or papermaking sludge can be produced according to the following steps.

In this case, in the molding and curing step, it is also possible to mold by a papermaking means without using a mold.

That is, before treating the blast furnace slag with a sulfuric acid solution in the first step, a sulfuric acid solution is first added to the waste paper or papermaking sludge, and the waste paper or papermaking sludge is treated with sulfuric acid to modify the fiber quality in the waste paper or papermaking sludge. Get the sludge slurry
Next, blast furnace slag is added to the slurry and the blast furnace slag is treated with sulfuric acid to obtain a sulfuric acid treated blast furnace slag slurry mixed with waste paper or papermaking sludge. After this, the second and third steps may be followed.

As the papermaking sludge, papermaking sludge discharged in large quantities at paper mills can be used. The concentration of the sulfuric acid solution used to treat the waste paper or papermaking sludge is the same as in the case of directly treating blast furnace slag, and the amount added is within the above concentration range per 100 parts of waste paper or papermaking sludge. 150 parts is preferred. The appropriate temperature for treating the waste paper or papermaking sludge with sulfuric acid is room temperature to 95°C.

According to the method of the present invention, blast furnace slag or fly ash is roughened and treated with sulfuric acid, and an aluminate is added to a kneaded mixture of blast furnace slag slurry or fly ash to which lime is added. The setting time for hardening the kneaded material to the extent that it can be demolded can be shortened to within about 1 hour, and the hardened blast furnace slag or fly ash obtained by the method of the present invention has a high initial strength, In addition, it is lightweight, water resistant, has excellent soundproofing properties and workability, and has physical properties similar to or better than those without the addition of aluminate, making it suitable as an interior and exterior building material.

Examples of the present invention are shown below (parts indicate parts by weight).

Example 1 200 parts of a sulfuric acid solution having a concentration of Io% was added to 200 parts of paper pattern sludge, and the mixture was treated with sulfuric acid at 85° C. for 1 hour to obtain a slurry of sulfuric acid-treated papermaking sludge. This slurry contains 10% blast furnace slag.
0 parts was added and treated with sulfuric acid for 3 hours to obtain sulfuric acid treated blast furnace slag slurry mixed with papermaking sludge. 50 parts of slaked lime was added to this blast furnace slag slurry to make the pn of the slurry 12.6. Next, 20 parts of calcium aluminate was added to this lime-added slurry and kneaded, and then the kneaded product was poured into a mold and hardened. The mixture completed setting in 1 hour. The mixture was poured into a mold and removed from the mold 2 hours later to obtain a cured product.

The above cured product was heated in a humid atmosphere at room temperature for 24 hours, and then in a humid atmosphere at 80°C.
After curing for 48 hours, the bulk specific gravity, bending strength, and compressive strength of the cured product were measured.

The results were as follows.

Bulk specific gravity 0.64 Bending strength 21 Kg/cat Compressive strength 55 Kg/co! Further, the cured product could be cut with a saw.

Example 2 160 parts of a 10% sulfuric acid solution was added to 100 parts of blast furnace slurry, and the slurry was treated with sulfuric acid for 3 hours to obtain a sulfuric acid-treated blast furnace slag slurry. 40 parts of slaked lime was added to this blast furnace slag slurry, and the pl+ of the slurry was adjusted to 12°7. Next, 15 parts of sodium aluminate was added to this lime-added slurry and kneaded, and then the kneaded product was poured into a mold and hardened.

The mixture completed setting in 1 hour. The mixture was poured into a mold and removed from the mold 2 hours later to obtain a cured product.

The above cured product was heated in a humid atmosphere at room temperature for 24 hours, and then in a humid atmosphere at 80°C.
After curing for 48 hours, the bulk specific gravity, bending strength, and compressive strength of the cured product were measured.

The results were as follows.

Bulk specific gravity 1.35 Bending strength 13.8 Kg/ctA compressive strength
140 Kglcsa Comparative Example 1 A cured product was obtained in exactly the same manner as in Example 1 except that calcium aluminate was not used and demolding was performed after 24 hours. The physical properties of this cured product are as follows in Example 1
It was almost the same as the one obtained. In addition, in this case, demolding is 2
After ~3 hours it was virtually impossible.

Comparative Example 2 In Example 1, aluminum sulfate, aluminum hydroxide, and Portland cement were used instead of calcium aluminate, but no accelerating effect on setting time was observed, and demolding was not possible after 2 to 3 hours. It was virtually impossible.

Procedural amendment 1, Indication of the case Japanese Patent Application No. 1982-1.02390 2, Name of the invention Method for producing hardened materials such as blast furnace slag 3, Person making the amendment Relationship to the case Patent applicant Fuji Noncombustible Construction Materials Industry Co., Ltd. Yasuo Arai Shigeki Aoki 4, Agent 601 Pacific Nogizaka, 6-29 Akasaka 9-chome, Minato-ku, Tokyo ■107 ff103 (419) 25-31 Voluntary amendment (amendment within 1 year and 3 months from the date of application) 6. Amendment Detailed description of the invention in the subject specification.

7. Contents of correction

Claims (2)

[Claims] (1) Treat blast furnace slag or fly ash with sulfuric acid,
Next, slaked lime or quicklime is added to the slurry obtained by this sulfuric acid treatment to adjust the pH of the slurry to 12 or more, and an aluminate is added and kneaded, followed by molding.
A method for producing a hardened material such as blast furnace slag, which comprises hardening. (2) The method for producing a hardened material such as blast furnace slag according to claim (1), wherein calcium aluminate, sodium aluminate, or alumina cement is used as the aluminate.