JP2839324B2 - Slag reduction agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a slag reducing agent for a centrifugally molded product, and more specifically, a pile, a pole, a steel pipe composite pile manufactured by centrifugally molding mortar or concrete, and The present invention relates to a slag reducing agent that reduces or prevents the occurrence of slag during the production of centrifugal force molded products such as steel pipe linings and fume tubes.

<Conventional technology and its problems> Conventionally, when manufacturing a concrete product such as a pile or a pole manufactured by centrifugal force forming, squeeze is squeezed out by centrifugal force. This noro contains 20-40% by weight of cement and fine particles of sand in addition to water and is highly alkaline, so it cannot be discharged directly from the factory to prevent pollution. However, there is a problem that it takes a lot of time and cost for the treatment of sedimentation filtration and wastewater and the neutralization of wastewater.

A method using ferrous sulfate, ferric sulfate, aluminum sulfate, or the like has been proposed to reduce the generation of the slag (Japanese Patent Application Laid-Open No. 61-104804).

However, this method sprinkles concrete when casting concrete into a mold to produce a centrifugal molding, and the purpose is not to reduce the amount of slag, but to centrifugal molding. This is a method for producing concrete in which the solid content in the generated slag is eliminated, and this method has a problem that the amount of dewatering is rather increased.

Furthermore, in this method, even if there is no solid content in the noro,
The water is dehydrated, and the dewatered water must be discarded. Since it is strongly alkaline, there are issues such as the necessity of neutralization and the addition of one extra step of sprinkling. .

Further, in order to prevent the generation of slag, for example, silica fume 2-1 to 100 parts by weight of Portland cement
0 parts by weight, and 5 to 20 parts by weight of fine particles of minerals such as natural rock, silica stone and cement of 6,000 to 9,000 cm ² / g of brane are used so that the total amount is 15 parts by weight or more. In addition, a method of manufacturing a centrifugally molded concrete product using silica fume, mineral fine powder, and 0.5 to 5 parts by weight of bentonite in a total amount of 15 parts by weight or more with respect to 100 parts by weight of Portland cement. It has been proposed (JP-A-62-7654).

However, this method has a problem that it is uneconomical because a large amount of mineral powder must be added.

The present inventors have previously kneaded with mortar or concrete, including water and solids, to reduce or prevent the generation of slag as a whole, and in view of economic efficiency, as a result of intensive study, The inventors have obtained the knowledge that the problem can be solved and completed the present invention.

<Means for Solving the Problems> That is, the present invention provides iron sulfate, magnesium salts and / or
Alternatively, it is a slag reducing agent for centrifugal force molded products containing an inorganic powder as a main component.

 Hereinafter, the present invention will be described in detail.

Examples of the iron sulfate according to the present invention include ferrous sulfate and ferric sulfate, and those commercially available for industrial use are used.

Even if iron sulfate is used alone as a powder or as an aqueous solution, it has a slag reduction effect even when added alone, but when used in combination with magnesium salts and / or inorganic powder, the slag reduction effect is remarkably exhibited.

The amount of iron sulfate used is preferably at most 3 parts by weight, more preferably at most 2 parts by weight, even more preferably at most 1.5 parts by weight with respect to 100 parts by weight of cement when used together with inorganic powder. . The lower limit of the amount of iron sulfate to be used is a water-reducing agent, especially bentonite among inorganic powders, and even when it is used as a suspension, a slag reduction effect is exhibited even at 0.001 part by weight. On the other hand, when the amount exceeds 3 parts by weight, the unit water amount increases, and the strength decreases, which is not preferable.

The magnesium salts according to the present invention (hereinafter referred to as Mg salts) include magnesium acetate, magnesium sulfate,
Examples thereof include magnesium nitrate, magnesium carbonate, basic magnesium carbonate, magnesium oxide, and magnesium hydroxide, and usually, commercially available ones are used.

In addition, concrete added with magnesium acetate, magnesium sulfate, and magnesium nitrate among Mg salts increases unit water volume, becomes plastic, and reduces water loss by improving water retention, but other magnesium carbonate salts It is observed that the increase / decrease of the unit water volume is small, but rather that the viscosity of the concrete increases, and that the slump drop has the effect of reducing the generation of slag. Magnesium carbonate and the like are good in strength, but it is easy to generate junka in the centrifugal molded body. Therefore, as the Mg salts, use of magnesium acetate, magnesium sulfate and magnesium nitrate salts is preferable. And the use of magnesium sulfate is most preferred.

The amount of the Mg salt used is preferably at most 3 parts by weight or less with respect to 100 parts by weight of cement, in total with iron sulfate.
It is more preferably at most 2 parts by weight, most preferably at most 1.5 parts by weight. When the lower limit of the amount used is a combination of iron sulfate and a water reducing agent, when added as an aqueous solution or suspension, the effect is exhibited even at 0.005 parts by weight, and the mixing ratio of iron sulfate, Mg salts and the water reducing agent is particularly There is no restriction.

In addition, the amount of iron sulfate and Mg salts used in combination with iron sulfate, Mg salts, water reducing agent and inorganic powder is preferably not more than 3 parts by weight, at most, based on 100 parts by weight of cement. It is more preferably at most 2 parts by weight, most preferably at most 1.5 parts by weight. The lower limit of this amount is not particularly limited. In the case where bentonite and a water reducing agent are used in combination and added as a suspension, the effect is exhibited even at 0.0005 parts by weight.

Further, the inorganic powder according to the present invention refers to a clay mineral or a siliceous substance.

Examples of the clay mineral include bentonite, acid clay, activated clay, clay, zeolite, and talc.

As the silica substance, silica fume, aerosil and diatomaceous earth, etc., and further, the maximum particle size of 60 μm collected by a back filter when grinding silica such as fused silica.
Ultra fine powder silica and the like.

In particular, the use of bentonite and silica fume is preferred in view of the effect of promoting the reduction of slag, economic efficiency and stability of the supply source.

Bentonite is a clay mineral belonging to the montmorillonite group and has a swelling property, but the higher the degree of swelling, the more the small amount of the clay mineral promotes the effect of reducing slag.

The swellability of bentonite differs depending on the production area and the deposit, and in general, the degree of swelling of bentonite is determined by the ACC method (Americannn).
Those having a degree of swelling of about 5 to 40 according to Collid Campany standard are commercially available. Bentonite has a different swelling effect depending on its degree of swelling. For the same amount used, the larger the degree of swelling, the greater the effect of reducing slag and the degree of swelling is 10%.
It is preferable to use the above bentonite.

Further, silica fume is amorphous silica as an ultrafine powder that is by-produced during the production of metallic silicon or a silicon alloy.

In the present invention, among the inorganic powders, those containing water of crystallization are added in terms of anhydrous salts, and those containing many impurities are added in terms of active ingredients.

The amount of the inorganic powder used is preferably at most 5 parts by weight, more preferably 3 parts by weight or less, and even more preferably 0.05 to 2 parts by weight, based on 100 parts by weight of cement in mortar or concrete. If it exceeds 5 parts by weight, the amount of kneading water increases and there is a component that lowers the strength, which is not preferable.

The lower limit of the addition amount of the inorganic powder varies depending on the method of use, and is not particularly limited.For example, iron sulfate, Mg
Used in combination with salts, soluble aluminum compounds and water reducing agents,
By adding it as a suspension, bentonite exhibits a slag reduction effect even with a small addition of 0.01 part by weight with respect to 100 parts by weight of cement.

Furthermore, in the present invention, the combined use of a soluble aluminum compound promotes the slag reduction effect.

Here, the soluble aluminum compound is magnesium sulfate, aluminum nitrate, sodium aluminate, potassium aluminate, alum, one or two or more selected from the group consisting of alumite and calcined alunite, Commercially available products for industrial use can be used as they are.

In the present invention, when iron sulfate, Mg salts and a soluble aluminum compound are used in combination, the total amount thereof is used as a cement.
At most 3 parts by weight, preferably 100 parts by weight,
It is more preferably at most 1.5 parts by weight, more preferably at most 1.5 parts by weight. The lower limit of the amount used is not particularly limited. When used as an aqueous solution or suspension in combination with a water reducing agent, the effect of addition is exhibited in a small amount, and the total amount is 0.00
The slag reduction effect is exhibited from about 5 parts by weight.

The mixing ratio of iron sulfate and Mg salts, and further, when a soluble aluminum compound is used in combination, is not particularly limited.

Furthermore, when iron sulfate, Mg salts, soluble aluminum compound and inorganic powder are used together, the amount used is 10 cement.
The total amount of iron sulfate, Mg salts and soluble aluminum compound is preferably at most 3.0 parts by weight, more preferably at most 2.0 parts by weight, even more preferably at most 1.5 parts by weight with respect to 0 parts by weight. The lower limit of the amount used is not particularly limited. For example, when a water reducing agent and bentonite are used in combination and used as a suspension, a slag reducing effect is obtained even at 0.0005% by weight, and exceeds 3.0 parts by weight. Is not preferred because the strength decreases greatly.

In the present invention, a combination use of a slag reducing agent and a water reducing agent is preferred. In particular, when the slag reducing agent of the present invention is added as a powder or when added as an aqueous solution or suspension, it is better to add it as an aqueous solution or suspension together with a water reducing agent than in the case of adding it as an aqueous solution or suspension. Shows the preventive effect.

The water reducing agent used in the present invention is not particularly limited in terms of components, and it is possible to use a general water reducing agent such as lignin sulfonate, oxycarboxylate and polyol, or a high-performance water reducer. . Among them, the use of a high-performance water reducing agent, in which the unit water amount increases to obtain the same degree of slump in the slag reducing agent of the present invention, has a large water reduction rate, and can control the water reduction rate with the amount used. .

A high-performance water reducing agent is a water reducing agent having a large water reduction rate that does not cause air entrainment or transient setting delay even when used in a relatively large amount, and also does not cause abnormal setting, such as polyalkylallyl sulfonate and melamine. Formalin resin sulfonate and the like.

Generally, commercially available high-performance water reducing agents are those containing any one of the above as main components, and polyalkylallyl sulfonates include naphthalenesulfonic acid formalin condensate, methylnaphtansulfonic acid formalin condensate and anthracenesulfonic acid. Formalin condensate and the like,
As a commercially available product, Kao Corporation product name "Mighty 100"
And “Mighty 150”, “Daiichi Kogyo Seiyaku Co., Ltd. product name“ Cellflow 110P ”, etc., Takemoto Yushi Co., Ltd. product name“ Pole Fine 510N ”, etc. PS, Sunflow PSR, etc., and
There are “FT-500” (trade name, manufactured by Denki Kagaku Kogyo Co., Ltd.), and as the melamine formalin resin sulfonate, “Merment F-10” or “Merment F” manufactured by Showa Denko KK
-20 "and the product name" NL-4000 "manufactured by Nisso Master Builders Co., Ltd.

In the present invention, the amount of the water reducing agent used for cement may be the amount specified by the manufacturer or 2
The amount is about 3 to 3 times, and the amount does not cause abnormal coagulation.

When using a high-performance water reducing agent as a water reducing agent, relative to 100 parts by weight of cement, at most 2.0 parts by weight, preferably 0.3 to 1.8 parts by weight, more preferably 0.4 to 1.5 parts by weight in terms of solid content. . As the amount of the high-performance water reducing agent used increases, the amount of generated slag increases in centrifugal molding, although the water reduction rate increases. Therefore, the required amount of the slag reducing agent of the present invention also changes. However, if it exceeds 2.0 parts by weight, it is difficult to suppress the generation of slag even if the amount of the slag reducing agent of the present invention is increased, which is not preferable.

The cement used in the present invention refers to various portland cements such as ordinary / early strong / super fast / moderate heat, various mixed cements obtained by mixing fly ash, silica and blast furnace slag with this portland cement, and blast furnace slabs. It is a cement or the like containing fine powder, and the use of a high-strength admixture containing gypsum or silica fume as a main component or an expanding material is not particularly limited.

The method of kneading the mortar or concrete is not particularly limited and may be a conventional method, and the method of adding the slag reducing agent of the present invention may be such that the powders are separately or mixed and charged into a mixer. It may be added in advance as an aqueous solution, but it is most preferable to add it as an aqueous solution or suspension in combination with the water reducing agent.The water reducing agent and the slag reducing agent are added to the kneading water measuring tank. It is most convenient to weigh together, stir and add.

The centrifugal force forming method is not particularly limited, either. For 1 to 3 minutes at a low speed of GNo. 3 to 5, and 3 at a medium speed of GNo.
５5 minutes, it is preferable to perform at a high speed of GNo.30-40 for 3-5 minutes, but when the mortar or concrete using the noro reduction agent of the present invention has a low slump of, for example, 3 cm or less,
Since the mortar or concrete does not easily move during centrifugal molding, for example, it is preferable to perform the low speed at G No. 3 or less for 3 minutes or more. When GNo.3 is exceeded, it is 1-2 cm from the outer diameter of the centrifugal molded body.
Junkers are easily formed along the circumferential direction at the inside, and mortar or concrete may not spread to the end unless centrifugal molding is performed for 3 minutes or more. At medium speed, there is no need to stick to the GNo. And the centrifugal force forming time at all. High speed is calculated by the inner diameter up to the inside of the tube thickness of the centrifugal molded body, GN
o.27 or better. If it is less than GNo.27, the mortar or concrete may not be formed properly on the inner surface. Also,
The high-speed time is preferably 1 minute or more.

Furthermore, vibration centrifugal molding, which is performed while vibrating at a low or medium speed, is preferable because it does not easily produce a jumper even with mortar or concrete that is difficult to move with plastic, and the finish of the molded body is improved.

<Example> Hereinafter, the present invention will be described in detail based on examples.

Example 1 Using the basic concrete composition shown in Table 1, Table 2
Using a water reducing agent, change the type and amount of iron sulfate and Mg salts as shown in the figure, knead the concrete, put 18 kg of concrete in a φ20 × 30 ^L × 5 ^t formwork, and fill the hollow part of the formwork. After using the GNo. Calculated with the center diameter of the wall thickness, use the GNo.
The mixture was kneaded under the centrifugal molding conditions of No. 4 for 2 minutes at medium speed and G No. 35 for 2 minutes at high speed, and after 15 minutes, a centrifugal molded product was molded, and the amount of squeezed out was measured.

In addition, a concrete specimen of φ10 × 20cm was prepared,
Curing in advance at 4 ℃ for 4 hours, then at a heating rate of 15 ℃ / h
After raising the temperature to 65 ° C and keeping the steam for 4 hours, shut off the steam valve, let it cool naturally in the curing tank until the next day, remove it, remove it, and cure it in a room at 20 ° C until the 7th day of material age. Was measured for compressive strength.

The slag reducing agent and water reducing agent are indicated in parts by weight with respect to 100 parts by weight of cement for simplicity, and changes in the unit water volume when iron sulfate, Mg salts and water reducing agent are added are not corrected without compounding.ゝ Kneaded and used. Table 2 shows the water amount and the slump value together with the measurement results.

The slag reducing agent was mixed with cement, kneaded with sand or crushed stone to obtain dry concrete, and kneading water in which a water reducing agent was dissolved was added thereto, and 30 l of concrete was kneaded.

<Materials> Cement: Ordinary Portland cement manufactured by Denki Kagaku Kogyo Co., Ltd., specific gravity 3.16 Sand: Himekawa, Niigata Prefecture, river sand, specific gravity 2.65 Crushed stone: Same as above, crushed stone, specific gravity 2.68 Ferrous sulfate A-1: ferrous sulfate, reagent Primary A-2: ferric sulfate, 〃 Mg salts B-1: magnesium acetate, 〃 B-2: magnesium sulfate, 〃 B-3: magnesium nitrate, Ｂ B-4: magnesium carbonate, industrial B-5: Basic magnesium carbonate, first grade reagent B-6: magnesium oxide, first grade reagent B-7: magnesium hydroxide, 、 water reducing agent D-1: trade name “Selflo-, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
110P "Polyalkyl allyl sulfonate-based powder.

The asterisks (*) in Table 2 indicate that the end of the centrifugally formed body and the outer periphery became junk.

As shown in Table 2, iron sulfate alone has the effect of reducing the generation of slag, but by using Mg salts in combination,
Slag reduction is more effectively achieved.

When used in combination with Mg salts, the more the amount added, the greater the slag reduction effect. However, if the total amount exceeds 3 parts by weight with respect to 100 parts by weight of cement, the unit water amount increases, and plain water without a water reducing agent is added. Due to the decrease in strength or slump drop, the concrete does not elongate even at the time of centrifugal force forming, and it is easy to generate jumpers, which is not preferable.

In addition, when iron sulfate and Mg salts are used in combination, the total amount is preferably 2 parts by weight or less, and more preferably 1.5 parts by weight or less in terms of strength.

Example 2 As shown in Table 3, the procedure was performed in the same manner as in Example 1 except that an inorganic powder was used instead of Mg salts. The results are shown in Table-3.

<Materials used> Inorganic powder C-1: bentonite, trade name of "Sieving" manufactured by Toyoshun Mining Co., Ltd. ACC method swelling degree 10 C-2: bentonite, Kanto Bantonite Industry Co., Ltd.
Product name “Premium Gel” swelling degree of ACC method 35 or more C-3: Acid clay, Kanto Bentonite Industry Co., Ltd. product name “Acid clay” C-4: Activated clay, Kanto Bentonite Industry Co., Ltd. product name Galeon Earth "C-5: Clay, brand name" SAM Clay "manufactured by Kanto Bentonite Industry Co., Ltd. C-6: Zeolite, brand name" SGW "manufactured by Kanto Bentonite Industry Co., Ltd. C-7: Talc, Kanto Bentonite Industry ( C-8: Silica fume, Nippon Heavy Chemical Industries, Ltd. product name "SF Powder" C-9: Aerosil, Nippon Aerosil Co., Ltd. product name "Aolosil 50" C- 10: Diatomaceous earth, calcined product from Noto Wakura C-11: Fused silica, manufactured by Denki Kagaku Kogyo Co., Ltd., back filter product when crushed fused silica, maximum particle size 50
μ As shown in Table 3, when iron sulfate and an inorganic powder are used in combination, if the amount of the inorganic powder exceeds 5 parts by weight, a decrease in strength due to an increase in the unit water amount is large, which is not preferable.

When the content of iron sulfate exceeds 3 parts by weight, the strength is greatly reduced, and it is understood that the strength is preferably 2 parts by weight or less, and the strength is more preferably 1.5 parts by weight or less.

Example 3 As shown in Table 4, the procedure was performed in the same manner as in Example 1 except that the types of iron sulfate, Mg salts, inorganic powder and water reducing agent were changed and used. The results are shown in Table-4.

<Materials used> Water reducing agent D-2: Showa Denko KK product name "Melment F-
10) Principal component melamine formalin resin sulfonate, powder.

D-3: Trade name “Darlex WRDA” manufactured by Denka Grace Co., Ltd. Standard addition amount of cement × 0.4%, ligninsulfonate as main component, liquid.

From Table-4, the water reducing agent is preferably 2.0 parts by weight or less,
By weight or less is more preferable, including the strength balance,
0.4 to 1.5 parts by weight is indicated to be most preferred.

Example 4 Experiment Nos. 1-4 to 7, 2-1 to 4, 2 to 25 to 28, 3-1
For each of Nos. 1 to 3, the components and the water reducing agent were converted into an aqueous solution or suspension in the total amount of kneading water, added to dry kneaded dry concrete, the concrete was kneaded, and centrifugally formed as in Example 1 to measure the amount of slag generated. . The results are shown in Table-5.

From Table-5, iron sulfate, Mg salts, inorganic powder and water reducing agent are used in combination to form an aqueous solution or suspension and then added.
It is shown that the slag reduction effect is improved with a small amount.

Example 5 As shown in Table-6, as in Example 1, except that the type and amount of the soluble aluminum compound were changed using ferrous sulfate, magnesium acetate, bentonite and a high-performance water reducing agent. went. The results are shown in Table-6.

<Material used> Soluble aluminum compound E-1: aluminum sulfate,
First grade reagent manufactured by Wako Pure Chemical Industries, Ltd. E-2: aluminum nitrate, 〃 E-3: potassium alum, 〃 E-4: sodium aluminate, 〃 E-5: calcined alum, Katsumitsuyama, Hiroshima Prefecture Production, Brain
Pulverized to 3,000cm ² / g, baked at 600 ° C, purity 90% As shown in Table-6, in the combined use of iron sulfate, Mg salts and soluble aluminum compound, as the amount of addition increases, the slag reduction effect increases, but the unit water amount also increases, and the strength falls below the plain strength. Therefore, the total amount of the three components is preferably 3 parts by weight or less, more preferably 2 parts by weight or less, and most preferably 1.5 parts by weight or less.

Further, when the inorganic powder is used in combination, the amount of water increases and the strength decreases greatly. Therefore, the inorganic powder is preferably 5 parts by weight or less, more preferably 3 parts by weight or less.

<Effect of the Invention> As described above, in a concrete product manufactured by centrifugal force molding as described in the examples, iron sulfate, Mg salts and / or inorganic iron powder, and further,
By using a soluble aluminum compound in combination, the generation of slag can be reduced with a small amount.

Furthermore, when the aqueous solution or suspension is used in combination with the water reducing agent and then added during kneading of the concrete, the slag reduction effect is exhibited with a smaller amount, and the slag treatment or the like becomes unnecessary.

 And the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C04B 22/10 C04B 22/10 24/04 24/04 (56) References JP-A-56-160358 (JP, A) JP-A 56-161108 (JP, A) JP-A-61-104804 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C04B 22/06-22/14 C04B 24/04 B28B 1 / 20 B28B 21/30

Claims (1)

(57) [Claims] 1. A slag reducing agent for centrifugally molded products comprising iron sulfate, magnesium salts and / or inorganic powder as main components.