JP4302119B2 - 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 nature conservation, ground granulated blast furnace slag as an alternative to natural sand, and a particle size adjusted product obtained by pulverizing this to adjust the particle size (hereinafter simply referred to as granulated blast furnace slag, etc.) ) Is increasingly used for fine aggregates for concrete. Granulated blast furnace slag, etc. is stored for a long period of time in a piled state for waiting for shipment or use, and is often transported for a long period of time by ship etc. When transported, it will solidify and eventually become a rock mass, and it can no longer be used as a substitute for natural sand as described above, so when using granulated blast furnace slag as a substitute for natural sand, etc. Is strongly required to prevent it from consolidating even if it is stored or transported over a long period of time. The present invention relates to an anti-caking agent such as blast furnace granulated slag that meets such requirements.

Conventionally, as an anti-caking agent such as granulated blast furnace slag, 1) alkylene oxide adducts of aliphatic oxycarboxylic acids and salts thereof (see, for example, Patent Documents 1 and 2), 2) acrylic acid polymers (for example, Patent Documents) 3) and 3) phosphonic acid derivatives (see, for example, Patent Document 5) and the like are known. However, although these conventional anti-caking agents have a corresponding effect, there is a problem that the effect is insufficient to meet the demand for stable anti-caking properties over a long period of time. The quality and properties of blast furnace granulated slag and the like vary depending on the conditions at the time of production. However, the variation in quality and properties also affects the anti-caking property of the anti-caking agent used for these, for example, blast furnace granulation When calcium ions are eluted from the slag and the pH of pore water existing between the particles rises and the caking property is increased, the anti-caking agent used in such blast furnace granulated slag is prevented. The properties are significantly reduced.
JP-A-6-127986 JP 2001-58855 A JP 2003-160364 A JP 2004-99389 A JP 2005-82426 A

  The problem to be solved by the present invention is a consolidation that can sufficiently prevent consolidation of blast furnace granulated slag and the like stably over a long period of time without being affected by variations in quality or properties of blast furnace granulated slag or the like. It is in place to provide an inhibitor.

  Thus, as a result of researches to solve the above problems, the present inventors have found that a specific two-component system is properly used as an anti-caking agent such as blast furnace granulated slag. .

  That is, the present invention is an anti-caking agent such as granulated blast furnace slag, containing 30 to 99% by mass of the following A component and 70 to 1% by mass of the following B component, and both in total. The present invention relates to an anti-caking agent comprising 100% by mass.

  Component A: at least one selected from an acrylic acid polymer having a mass average molecular weight of 1,000 to 100,000 and an alkali metal salt thereof

  Component B: at least one selected from phosphoric acid, sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, tripolyphosphoric acid and sodium tripolyphosphate

  The component A used in the anti-caking agent of the present invention is at least one selected from an acrylic acid polymer having a mass average molecular weight of 1,000 to 100,000, preferably 3000 to 50,000, and an alkali metal salt thereof. Examples of the alkali metal salt of the acrylic acid polymer include sodium salt, potassium salt, lithium salt and the like of the acrylic acid polymer, and sodium salt is preferable from an industrial viewpoint. In the present invention, the weight average molecular weight means the weight average molecular weight in terms of polyethylene glycol according to the GPC method, and the alkali metal salt of the acrylic acid polymer is completely contained in the acrylic acid polymer using, for example, an alkali metal hydroxide. It means that not only the sum but also the partially neutralized one is included.

  In addition to polyacrylic acid obtained by homopolymerizing acrylic acid, acrylic acid polymer is copolymerized with acrylic acid in a range of less than 10 mol% of other vinyl monomers copolymerizable with acrylic acid. It means that the copolymer obtained by doing is also included. Specific examples of the copolymerizable vinyl monomer include methacrylic acid or a salt thereof, acrylamide, methacrylic acid hydroxyethyl ester, acrylic acid methyl ester, (meth) allyl sulfonate, and the like. The body is mentioned. Any of the acrylic acid polymers described above can be synthesized by known methods.

  The component B used in the anti-caking agent of the present invention is at least one selected from phosphoric acid, sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, tripolyphosphoric acid and sodium tripolyphosphate. From the viewpoint, phosphoric acid and sodium tripolyphosphate are preferable. In particular, when an acrylic acid polymer is used as the A component, sodium tripolyphosphate is preferably used as the B component, and when an alkali metal salt of an acrylic acid polymer is used as the A component, phosphorus is used as the B component. It is preferable to use an acid.

  The anti-caking agent of the present invention comprises 30 to 99% by mass of the A component and 70 to 1% by mass of the B component, preferably 40 to 97% by mass of the A component and 60 to 3% by mass of the B component. It contains, and both are contained so that it may become 100 mass% in total. The content ratios of the A component and the B component are preferably selected as appropriate in relation to the quality and properties of the blast furnace granulated slag and the like within the range of the content ratio as described above.

  Although the anti-caking agent of the present invention has been described above, the anti-caking agent of the present invention preferably has an aqueous solution having a concentration of 1% by mass of 4 to 10, more preferably 5 to 9. preferable. Those having a numerical value range in which the pH of an aqueous solution having a concentration of 1% by mass exhibits a more excellent anti-caking effect without being affected by variations in quality or properties such as granulated blast furnace slag.

  The anti-caking agent of the present invention is usually in a proportion of 0.002 to 0.5 parts by mass, preferably 0.005 to 0.1 parts by mass, per 100 parts by mass of blast furnace granulated slag and the like. Use.

  The anti-caking agent of the present invention is usually diluted with water to form an aqueous solution, preferably an aqueous solution having a concentration of 1.5 to 15% by mass, and this aqueous solution is consolidated per 100 parts by mass of blast furnace granulated slag and the like. As an inhibitor, it sprays and uses it in the ratio of 0.002-0.5 mass part, Preferably it is the ratio of 0.005-0.1 mass part.

  When using the anti-caking agent of the present invention, other additives can be used in combination for the purpose. Examples of such other additives include antiseptics, rust inhibitors, and antioxidants.

  According to the anti-caking agent of the present invention described above, the caking of granulated blast furnace slag and the like can be sufficiently prevented stably over a long period of time without being affected by the quality or properties of the granulated blast furnace slag or the like. it can. Moreover, when blast furnace granulated slag or the like thus prevented from being consolidated is used as a part of the fine aggregate for concrete, there is no adverse effect on the physical properties of the concrete.

  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 the examples. In the following examples and the like, unless otherwise indicated, “part” means “part by mass” and “%” means “% by mass”.

Test Category 1 (Synthesis of acrylic acid polymer and alkali metal salt used as component A)
Synthesis of acrylic acid polymer (a-1) 72 g of acrylic acid, 3.5 g of 3-mercaptopropionic acid and 687.5 g of water were charged and mixed in a reaction vessel, and the atmosphere was replaced with nitrogen, and then the atmosphere was changed to nitrogen. The temperature of the reaction system is kept at 60 ° C. in a warm water bath, 8 g of 20% sodium persulfate aqueous solution is added dropwise to initiate the polymerization, the polymerization reaction is carried out for 4 hours, and the acrylic acid polymer (a-1 ) Was obtained. The acrylic acid polymer (a-1) had a mass average molecular weight of 7,300.

Synthesis of acrylic acid polymer (a-2) A 10% aqueous solution of acrylic acid polymer (a-2) described in Table 1 was obtained in the same manner as acrylic acid polymer (a-1). .

Synthesis of alkali metal salt of acrylic acid polymer (a-3) A reaction vessel was charged with 72 g of acrylic acid, 3.5 g of 3-mercaptopropionic acid and 742 g of water and mixed, and 66 g of 30% aqueous sodium hydroxide solution was added. The mixture was neutralized by stirring. After substituting the atmosphere with nitrogen, the temperature of the reaction system was kept at 60 ° C. in a warm water bath under a nitrogen atmosphere, and 10 g of 20% sodium persulfate aqueous solution was added dropwise to initiate polymerization, and the polymerization reaction was carried out for 4 hours. Thus, a 10% aqueous solution of an alkali metal salt of an acrylic acid polymer (a-3) was obtained. The degree of neutralization of the alkali metal salt (a-3) of this acrylic acid polymer was 0.5, and the mass average molecular weight was 4,200.

Synthesis of alkali metal salts (a-4) to (a-6) of acrylic acid polymer The acrylic acid system described in Table 1 in the same manner as the alkali metal salt (a-3) of acrylic acid polymer A 10% aqueous solution of polymer alkali metal salts (a-4) to (a-6) was obtained.

In Table 1,
Degree of neutralization: moles of carboxyl groups of acrylic acid polymer stoichiometrically neutralized with alkali metal hydroxide / moles of all carboxyl groups of acrylic acid polymer

Test Category 2 (Preparation of anti-caking agent)
Example 1 {Preparation of 10% aqueous solution of anti-caking agent (P-1)}
An anti-caking agent (P-1) was prepared by mixing 80 parts of a 10% aqueous solution of the acrylic acid polymer (a-1) synthesized in Test Category 1 as component A and 20 parts of a 10% aqueous solution of sodium tripolyphosphate as component B. ) Was prepared. The pH of the aqueous solution having a solid content concentration of 1% obtained by diluting the anti-caking agent (P-1) with water was 4.3.

Examples 2 to 13 and Comparative Examples 1 to 19 {Preparation of 10% aqueous solutions of anti-caking agents (P-2) to (P-13) and (R-1) to (R-19)}
Similarly to the anti-caking agent (P-1), 10% aqueous solutions of the anti-caking agents (P-2) to (P-13) and (R-1) to (R-19) were prepared. Table 2 summarizes the contents of the anti-caking agents prepared above.

In Table 2,
pH: pH of an aqueous solution having a solid content concentration of 1%
a-1 to a-6: Acrylic acid polymer or alkali metal salt thereof listed in Table 1 b-1: sodium tripolyphosphate b-2: phosphoric acid b-3: sodium phosphate b-4: tripolyphosphoric acid b- 5: Sodium dihydrogen phosphate b-6: Sodium monohydrogen phosphate c-1: Sodium sulfate c-2: Sodium chloride c-3: Sodium nitrate d-1: Sulfuric acid

Test category 3 (Evaluation of anti-caking property)
Blast furnace granulated slag fine aggregate {Fukuyama blast furnace granulated slag made by JFE Mineral Co., Ltd. adjusted to the particle size distribution of 5mm blast furnace granulated slag fine aggregate according to JIS-A5011 (concrete slag aggregate) The pH value of the pore water is higher than that of the standard (having a pH value of less than 9.5 to 11) (having a pH value of 11.7)}. % Aqueous solution was sprayed so as to have the addition amount shown in Table 3, and mixed with a hand scoop. After mixing for 5 minutes with a tilting mixer, add water to a water content of 10%, mix again with a tilting mixer for 5 minutes, and granulate blast furnace granulated slag with anti-caking agent attached. The material was obtained. The blast furnace granulated slag fine aggregate to which the anti-caking agent is adhered in this manner is filled in a cylindrical container having an inner diameter of 100 mm up to a height of 125 mm, which corresponds to a storage height of 10 m for the blast furnace granulated slag. A specimen was loaded with a pressure of 15 MPa. The specimen was sealed in a container in order to prevent evaporation of moisture, and was accelerated and cured for up to 16 weeks in a constant temperature room at 80 ° C. After curing for a predetermined period, the specimen was removed and the particle size was measured. The particle size was measured using a sieve having a mesh opening of 5 mm, the mass of the material remaining on the sieve without passing through the sieve was measured, and the ratio in the specimen was obtained (the ratio of 5 mm sieve in Table 3). The results are summarized in Table 3. In Table 3, it means that the consolidation of a blast-furnace granulated slag fine aggregate is prevented, so that the numerical value (%) on a 5 mm sieve is low.

In Table 3,
Addition amount: part by mass of anti-caking agent (solid content) per 100 parts by mass of granulated blast furnace slag fine aggregate R-20: sodium gluconate

Test Category 4 (Evaluation of granulated blast furnace slag mixed with anti-caking agent as fine aggregate for concrete)
The concrete of each example was prepared as follows on the conditions of the mixing | blending number 1 of Table 4. Add 50L pan-type forced kneading mixer with normal Portland cement (density 3.16, brane value 3300), Oikawa water sand (density 2.63) as fine aggregate and anti-caking agent as in test category 3 Two types of blast furnace granulated slag (Fukuyama blast furnace granulated slag manufactured by JFE Mineral Co., Ltd., density 2.74) and coarse aggregate (Okazaki crushed stone, density 2) mixed by spraying so that the amount is 0.03 .68) were sequentially added and kneaded for 15 seconds. Then, in each example, 0.8% amount of high-performance AE water reducing agent (trade name Tupol HP-11 manufactured by Takemoto Yushi Co., Ltd.) is mixed with the cement so that the target slump is within the range of 18 ± 1 cm. And kneaded for 2 minutes. At this time, an AE agent (trade name AE-300 manufactured by Takemoto Yushi Co., Ltd.) was added so that the target air amount was 4 to 5%. The physical properties of the concrete of each test example thus prepared were evaluated by the following methods. The results are summarized in Table 5.

Slump: Measured according to JIS-A1101.
Air amount: Measured according to JIS-A1128.
Compressive strength: measured in accordance with JIS-A1108.
Setting time: Measured according to JIS-A6204.

In Table 4,
* 1: Blast furnace granulated slag mixed by spraying anti-caking agent

In Table 5,
Type of anti-caking agent: Anti-caking agent listed in Table 2 * 2: No anti-caking agent added * 3: Concrete kneaded with compound No. 2 in Table 4, and granulated blast furnace slag Unmixed concrete

Claims (6)

An anti-caking agent for granulated blast furnace slag or its particle size-adjusted product, which contains 30 to 99% by mass of the following A component and 70 to 1% by mass of the following B component, and both are 100 in total. An anti-caking agent characterized by being contained in an amount of mass%.
Component A: at least one selected from acrylic acid polymers having a mass average molecular weight of 1000 to 100,000 and alkali metal salts thereof Component B: phosphoric acid, sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, tripolyphosphoric acid And at least one selected from sodium tripolyphosphate   The anti-caking agent according to claim 1, wherein the pH of the aqueous solution having a concentration of 1% by mass is 4 to 10.   The anti-caking agent according to claim 1 or 2, wherein the component A is at least one selected from an acrylic acid polymer having a mass average molecular weight of 3000 to 50000 and an alkali metal salt thereof.   The anti-caking agent according to any one of claims 1 to 3, wherein the component A is an alkali metal salt of an acrylic acid polymer and the component B is phosphoric acid.   The caking inhibitor according to any one of claims 1 to 4, wherein the alkali metal salt of the acrylic acid polymer is a sodium salt of an acrylic acid polymer. The anti-caking agent according to any one of claims 1 to 3, wherein the component A is an acrylic acid polymer and the component B is sodium tripolyphosphate.