JP4836261B2 - Anti-caking agent of granulated blast furnace slag or its particle size - Google Patents

Description

  The present invention relates to an anti-caking agent for blast furnace granulated slag or a particle size adjusted product thereof. In recent years, natural sand has been depleted, and from the viewpoint of resource conservation, blast furnace granulated slag and its particle size adjustment as an alternative to natural sand used for civil engineering materials and concrete fine aggregates, etc. Opportunities have been increasing to use the adjusted particle size (hereinafter simply referred to as blast furnace granulated slag, etc.). By the way, blast furnace granulated slag, etc. is stored for a long time in a piled state for waiting for shipment or use, and is often transported for a long time by ship etc., but this is stored for a long time as it is. When transported or transported, it solidifies and eventually becomes like a rock mass. Such consolidation is remarkable in summer when the temperature is high. The consolidated one cannot be used as a substitute for natural sand as described above, and if it is to be used as a substitute for natural sand, enormous labor is required. When blast furnace granulated slag or the like is used as a substitute for natural sand, it is required that the blast furnace granulated slag does not solidify during its long-term storage and transportation. The present invention relates to an anti-caking agent such as blast furnace granulated slag that meets such requirements.

Conventionally, as anti-caking agents such as granulated blast furnace slag, aliphatic oxycarboxylic acids and salts thereof (see, for example, Patent Document 1), lignin sulfonic acids and salts thereof (see, for example, Patent Document 2), saccharides (for example, Patent Document 3) And alkylene oxide adducts of aliphatic oxycarboxylic acids and salts thereof (for example, see Patent Document 4) have been proposed. These anti-caking agents are usually used by, for example, spraying the aqueous liquid diluted with water onto blast furnace granulated slag or the like. However, although these conventional anti-caking agents are different in degree, the anti-caking effect that they exhibit is insufficient, and in particular, blast furnace granulated slag using them is stored and transported over a long period of time. Then, water retention such as granulated blast furnace slag was originally low, and it is speculated that the anti-caking agent used for this would flow down due to dilution water or rain water, but the problem of preventing the expected anti-caking effect was not exhibited. is there. Further, depending on the anti-caking agent, when granulated blast furnace slag or the like using them is used as a fine aggregate for concrete, there is a problem that the strength of the obtained cured product is lowered.
Japanese Patent Laid-Open No. 54-130596 JP-A-57-95857 JP 58-104050 A JP 2001-58855 A

  The problem to be solved by the present invention is to sufficiently prevent consolidation of blast furnace granulated slag, etc. over a long period of time, and does not adversely affect the object of use such as blast furnace granulated slag, etc. It is in place to provide anti-caking agent.

The present invention for solving the above-mentioned problems is composed of a structural unit represented by the following chemical formula 1 and a structural unit formed from the following monomers, and a structure represented by the following chemical formula 1 in all the structural units. The present invention relates to an anti-caking agent such as blast furnace granulated slag, which is composed of one or two or more acrylic polymers having a number average molecular weight of 3000 to 100,000 having a unit of 60 mol% or more.

In chemical formula 1,
M: hydrogen atom, alkali metal, alkaline earth metal, ammonium or organic amine

  Monomer: One or more selected from methacrylic acid, methacrylic acid salt, hydroxyalkyl methacrylate and styrene sulfonic acid salt

  The anti-caking agent such as granulated blast furnace slag according to the present invention (hereinafter simply referred to as the anti-caking agent of the present invention) is a structural unit formed from the structural unit represented by the chemical formula 1 and the monomer. And one or two or more selected from acrylic polymers having 60% by mole or more of the structural unit represented by Chemical Formula 1 in all the structural units. Such acrylic acid polymers include acrylic acid copolymers, acrylate copolymers, acrylic acid copolymer salts, and the like.

  The acrylic acid polymer used as the anti-caking agent of the present invention forms a structural unit other than the structural unit represented by the monomer that forms the structural unit represented by Chemical Formula 1 and the structural unit represented by Chemical Formula 1. And a monomer to be copolymerized. The monomer that forms such another structural unit is one or more selected from methacrylic acid, a salt of methacrylic acid, a hydroxyalkyl methacrylate, and a salt of styrene sulfonic acid.

  In the acrylic acid polymer used as the anti-caking agent of the present invention, M in Chemical Formula 1 is 1) an alkali metal such as sodium, potassium or lithium, 2) an alkaline earth metal salt such as calcium or magnesium, 3 And organic amines such as ammonium), 4) triethanolamine, and diethanolamine.

  As the acrylic acid polymer used as the anti-caking agent of the present invention, a polymer having 5 to 30 mol% of structural units other than the structural unit represented by Chemical Formula 1 in all the structural units is preferable. This is because such an acrylic acid copolymer better prevents consolidation of blast furnace granulated slag and the like over a long period of time.

  As described above, M in Chemical Formula 1 is a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, or an organic amine, but the structural unit represented by Chemical Formula 1 is that in the case where M is sodium. preferable. The acrylic acid polymer used as the anti-caking agent of the present invention has a number average molecular weight of 3000 to 100,000. This is because the blast furnace granulated slag and the like are better prevented from being consolidated for a long time.

  Any of the acrylic acid polymers described above used as an anti-caking agent of the present invention can be synthesized by a known method.

  The anti-caking agent of the present invention is used in a proportion of 0.002 to 0.3 parts by weight per 100 parts by weight of blast furnace granulated slag and the like. When the use amount of the anti-caking agent of the present invention is less than 0.002 parts by weight per 100 parts by weight of granulated blast furnace slag, the anti-caking effect is not sufficiently exhibited, and conversely, it exceeds 0.3 parts by weight. However, the caking prevention effect is not exhibited for that, and it becomes uneconomical. When the anti-caking agent of the present invention is used for blast furnace granulated slag or the like, usually the anti-caking agent of the present invention or an aqueous liquid diluted with water is mixed while sprayed on the blast furnace granulated slag or the like.

  The anti-caking agent of the present invention is preferably used in a proportion of 0.005 to 0.1 parts by weight per 100 parts by weight such as granulated blast furnace slag. The anti-caking agent of the present invention is preferably diluted with water to form an aqueous liquid of 1.5 to 10% by weight, and such aqueous liquid is preferably used for blast furnace granulated slag and the like. This is because the blast furnace granulated slag and the like are better prevented from being consolidated for a long time.

  As is clear from the above, the present invention described above has an effect of sufficiently preventing consolidation of blast furnace granulated slag, etc. over a long period of time, and does not adversely affect the object to be used such as blast furnace granulated slag. There is.

Examples of the anti-caking agent of the present invention include the following 1) to 6).
1) An anti-caking agent comprising a copolymer of acrylic acid and methacrylic acid having a number average molecular weight of 3200 (structural units formed from acrylic acid / structural units formed from methacrylic acid = 90/10 (molar ratio)) .

  2) A copolymer of sodium acrylate-sodium methacrylate having a number average molecular weight of 5100 (constituent unit formed from sodium acrylate / constituent unit formed from sodium methacrylate = 75/25 (molar ratio)). Anti-caking agent.

  3) Copolymer of sodium acrylate-methacrylic acid 2-hydroxyethyl having a number average molecular weight of 7300 {structural unit formed from sodium acrylate / structural unit formed from 2-hydroxyethyl methacrylate = 80/20 (molar ratio) )}.

  4) Sodium acrylate-methacrylic acid 2-hydroxyethyl-sodium styrenesulfonate copolymer having a number average molecular weight of 6,600 {structural unit formed from sodium acrylate / structural unit formed from 2-hydroxyethyl methacrylate / Anti-caking agent comprising a structural unit formed from sodium styrenesulfonate = 75/15/10 (molar ratio)}.

  5) Copolymer of sodium acrylate-sodium styrenesulfonate having a number average molecular weight of 17,000 {structural unit formed from sodium acrylate / structural unit formed from sodium styrenesulfonate = 90/10 (molar ratio)} An anti-caking agent comprising:

  6) A copolymer of acrylic acid and methacrylic acid having a number average molecular weight of 6700 {a structural unit formed from acrylic acid / a structural unit formed from methacrylic acid = 75/25 (molar ratio)} sodium salt Anti-caking agent.

  Hereinafter, in order to make the configuration and effects of the present invention more specific, examples and the like will be described. However, the present invention is not limited to these examples. In the following examples and the like, unless otherwise indicated, parts means parts by weight and% means% by weight.

Test category 1 (Preparation of anti-caking agent)
Reference Example 1 (Preparation of anti-caking agent P-1)
A reaction vessel was charged with 313 g of a 30% aqueous solution of sodium acrylate {aqueous solution containing 94 g (1 mol) as sodium acrylate}, 3 g of 3-mercaptopropionic acid and 70 g of water, and dissolved uniformly with stirring. The atmosphere was replaced with nitrogen. Under a nitrogen atmosphere, the temperature of the reaction system was kept at 80 ° C. in a warm water bath, 8 g of a 20% aqueous solution of sodium persulfate was added dropwise to initiate polymerization, and the polymerization reaction was continued for 5 hours to complete the polymerization. A 25% aqueous liquid of a polymer of sodium acrylate (Reference Example 1) having a number average molecular weight of 1100 was prepared. This was designated as a 25% aqueous solution of anti-caking agent P-1.

Reference Examples 2 to 8 (Preparation of anti-caking agents P-2 to P-8)
In the same manner as the 25% aqueous liquid of the anti-caking agent P-1 of Reference Example 1, 25% aqueous liquids of the anti-caking agents P-2 to P-8 of Reference Examples 2 to 8 were prepared.

Reference Example 9 (Preparation of anti-caking agent P-9)
A reaction vessel was charged with 288 g of a 25% aqueous solution of acrylic acid {aqueous solution containing 72 g (1 mol) of acrylic acid}, 2.5 g of 3-mercaptopropionic acid and 54.3 g of water, and dissolved uniformly with stirring. Thereafter, the atmosphere was replaced with nitrogen. Under a nitrogen atmosphere, the temperature of the reaction system is kept at 80 ° C. in a warm water bath, 6 g of a 20% aqueous solution of sodium persulfate is added dropwise to initiate the polymerization, and the polymerization reaction is continued for 6 hours. Got. Next, after cooling the reaction system to 20 ° C., while maintaining the reaction system at 20 to 30 ° C., 40 g of granular sodium hydroxide was gradually added, so that the sodium of acrylic acid polymer having a number average molecular weight of 23,000 was obtained. A 25% aqueous solution of the salt (Reference Example 9) was prepared. This was designated as a 25% aqueous solution of anti-caking agent P-9.

Reference Example 10 (Preparation of anti-caking agent P-10)
A reaction vessel was charged with 313 g of a 30% aqueous solution of sodium acrylate {94 g (1 mol) as sodium acrylate}, 10.4 g (0.1 mol) of styrene, 4.5 g of 3-mercaptopropionic acid and 106 g of water, and stirred. The solution was uniformly dissolved while the atmosphere was replaced with nitrogen. Under a nitrogen atmosphere, the temperature of the reaction system is maintained at 80 ° C. in a warm water bath, 5 g of a 20% aqueous solution of sodium persulfate is added dropwise to initiate polymerization, and the polymerization reaction is continued for 5 hours to complete the polymerization. A 25% aqueous solution of a sodium acrylate-styrene copolymer (Reference Example 10) having an average molecular weight of 1800 was prepared. This was made into 25% aqueous solution of anti-caking agent P-10.

Reference Example 11 and Examples 12 to 16 (Preparation of anti-caking agents P-11 and P-12 to P-16)
25% aqueous solutions of anti-caking agents P-11 and P-12 to P-16 of Reference Example 11 and Examples 12 to 16 in the same manner as the 25% aqueous liquid of anti-caking agent P-10 of Reference Example 10 A liquid was prepared.

Example 17 (Preparation of anti-caking agent P-17)
216 g of acrylic acid 25% aqueous solution {54 g (0.75 mol) as acrylic acid}, 86 g of methacrylic acid 25 g aqueous solution {21.5 g (0.25) as methacrylic acid}, 3-mercaptopropion 4 g of acid and 58.8 g of water were charged and dissolved uniformly with stirring, and then the atmosphere was replaced with nitrogen. Under a nitrogen atmosphere, the temperature of the reaction system is kept at 80 ° C. in a warm water bath, 6 g of a 20% aqueous solution of sodium persulfate is added dropwise to initiate the polymerization, and the polymerization reaction is continued for 5 hours. Acrylic acid-methacrylic acid The copolymer of was obtained. Next, after cooling the reaction system to 20 ° C., while maintaining the reaction system at 20-30 ° C., 40 g of granular sodium hydroxide was gradually added, and the acrylic acid-methacrylic acid copolymer having a number average molecular weight of 6700 was added. A 25% aqueous solution of the combined sodium salt (Example 17) was prepared. This was designated as a 25% aqueous solution of anti-caking agent P-17.

Examples 18-20
A 25% aqueous liquid of the same anti-caking agent P-12 as in Example 12 was prepared. The contents of each example prepared above are summarized in Table 1.

Test category 2 (Evaluation of anti-caking agent 1)
50 kg of granulated blast furnace slag from Fukuyama, manufactured by Steel Pipe Mining Co., Ltd. {Granulate size adjusted to 5 mm blast furnace slag fine aggregate distribution according to JIS-A5011 (concrete slag aggregate)} was spread on a bat. Separately, a 25% aqueous solution of the anti-caking agent prepared in Test Category 1 was further diluted with water to prepare aqueous solutions having the use concentrations shown in Table 1. An aqueous liquid having a working concentration applied to the granulated slag spread on the vat is mixed with a hand scoop while spraying to the addition amount shown in Table 1 as an anti-caking agent, and the water content of the blast furnace granulated slag becomes 10%. Water was added as described above and mixed with a mixer for 5 minutes to obtain a granulated blast furnace slag to which an anti-caking agent was added. Thus, the granulated blast furnace slag to which the anti-caking agent is added is filled up to a height of 125 mm in a cylindrical container having an inner diameter of 100 mm, and a pressure of 1.5 kg / cm ² corresponding to the storage height of the granulated blast furnace slag is 10 m. The specimen was loaded. The specimen was sealed in a cylindrical container to prevent evaporation of moisture, and was cured in a thermostatic chamber at 80 ° C. for up to 10 weeks. After curing for a predetermined period, the specimen was unframed and the particle size was measured. The particle size was measured using a 5 mm sieve, and the amount of what remained on the sieve without passing through the sieve was measured, and the ratio was determined (the ratio on the 5 mm sieve in Table 1). The results are summarized in Table 1. In Table 1, it means that consolidation of blast-furnace granulated slag is prevented, so that the numerical value of a 5-mm sieve top ratio (%) is low.

In Table 1,
* 1: Indicated by a monomer corresponding to the structural unit of the acrylic acid polymer. Amount added: part by weight of anti-caking agent per 100 parts by weight of granulated blast furnace slag GS: sodium gluconate GS-4: gluconic acid Sodium ethylene oxide 4 mol adduct

Test Category 3 (Evaluation of anti-caking agent 2)
A 25% aqueous solution of the anti-caking agent prepared in Test Category 1 was further diluted with water to prepare aqueous solutions having the working concentrations shown in Table 2. After crushing blast furnace granulated slag with a crusher, spray the aqueous liquid of the concentration used on the crushed material as an anti-caking agent to the addition amount shown in Table 2, and sieve it with a screen to obtain 5mm blast furnace granulated water. 80 tons of granulated blast furnace slag adjusted to slag fine aggregate particle size was obtained. The granulated blast furnace slag to which the anti-caking agent was added was piled up outdoors in a small mound shape with a height of 3 m for 14 weeks, and at the time indicated in Table 2 during the field loading period, the penetration resistance was measured by the following method. The coefficient was obtained and the anti-caking property was evaluated. Here, when the penetration resistance coefficient is 0.45 or less, it is determined that there is no problem due to consolidation. The results are summarized in Table 2.
-Penetration resistance coefficient The penetration resistance measuring instrument described in the blast furnace slag aggregate concrete construction guideline was penetrated into the pile of piles, and the penetration resistance coefficient was calculated by the following formula. (Concrete Library No. 76 Blast Furnace Slag Aggregate Concrete Construction Guidelines P.21 Japan Society of Civil Engineers 1993)
Penetration resistance coefficient = 100cm Load when spring penetrates (kgf) / penetration length 100 (cm)
Or, penetration resistance coefficient = spring load maximum load 20kgf / spring load maximum load 20kgf penetration length (cm)

Test category 3 (Evaluation of anti-caking agent 3)
Under the mixing conditions described in Table 3, concretes of each example were prepared as follows. 50L pan-type forced kneading mixer, ordinary Portland cement (specific gravity 3.16, brane value 3300), Oikawa water sand (specific gravity 2.63) as fine aggregate, and aqueous liquid of anti-caking agent as in Test Category 2 Blast furnace granulated slag (Fukuyama produced by Steel Pipe Mining Co., Ltd., specific gravity 2.74) and coarse aggregate (Okazaki crushed stone, specific gravity 2.68) which were sprayed and mixed in order and empty for 15 seconds Kneaded. Next, in each example, the AE water reducing agent (trade name Tupol EX20 manufactured by Takemoto Yushi Co., Ltd.) is kneaded so that the target slump falls within the range of 18 ± 1 cm so that it becomes 0.2% by weight with respect to the cement weight. Added with water and kneaded for 2 minutes. At this time, an air amount adjusting agent (trade name AE200 manufactured by Takemoto Yushi Co., Ltd.) was added so that the target air amount was 4 to 5%. About the prepared concrete of each test example, the physical property was measured as follows. The results are summarized in Table 4.
Slump: Measured according to JIS-A1101 Air amount: Measured according to JIS-A1128 Compressive strength: Measured according to JIS-A1108

Claims (3)

A anti-caking agent for blast furnace slag or the particle size adjustment thereof, is composed of a structural unit derived from a monomer of the structural unit and the following represented by Chemical Formula 1 below, and in all the structural units anti-caking agent, characterized in that it consists of one or more selected from the number-average molecular weight 3,000 to 100,000 acrylic polymer of the organic over 60 mol% or more of structural units represented by the following Symbol of Formula 1 .

(In chemical formula 1,
M: hydrogen atom, alkali metal, alkaline earth metal, ammonium or organic amine)
Monomer: One or more selected from methacrylic acid, methacrylic acid salt, hydroxyalkyl methacrylate and styrene sulfonic acid salt The anti-caking agent according to claim 1, wherein the acrylic acid polymer has 5 to 30 mol% of structural units formed from the monomers in all the structural units.   The anti-caking agent according to claim 1 or 2, wherein the acrylic polymer has a structural unit represented by Chemical Formula 1 when M is sodium.