JP5883243B2 - Method for producing hydraulic powder - Google Patents

Description

  The present invention relates to a method for producing hydraulic powder, which includes a step of pulverizing a hydraulic compound using a pulverization aid.

  Various hydraulic powders are produced by pulverizing hydraulic compounds such as Portland cement clinker and blast furnace slag. For example, Portland cement is manufactured by adding an appropriate amount of gypsum to a clinker obtained by firing raw materials such as limestone, clay, iron slag and the like, and pulverizing them. At that time, a grinding aid such as diethylene glycol or triethanolamine is used to increase the grinding efficiency of the hydraulic compound. In the pulverization step, it is desirable that the hydraulic compound is made as efficiently as possible with the desired particle size without reducing the strength of the cured body using the obtained hydraulic powder.

  As a grinding aid, for example, in Patent Document 1, glycerin monoacetate (monoacetin) is added to a clinker 100 for grinding the clinker for the purpose of improving the grinding efficiency of the clinker and the compressive strength when the cement is cured. A method for producing a cement that adds and pulverizes 0.05 to 0.50 parts by weight with respect to parts by weight is disclosed.

  Further, in Patent Document 2, for the purpose of providing a method for producing a high-strength cement that can sufficiently ensure the effect of improving physical properties using granulated ultrafine particles with good handling properties, There is disclosed a method for producing a high-strength cement that is pulverized by adding 50 parts by weight or less of a granular material having a particle diameter of less than 2 mm and a pulverization aid to 100 parts by weight of a clinker. Examples of the grinding aid include amines such as triethanolamine and diethanolamine and glycols such as diethylene glycol.

US Patent No. 2203809 JP-A-5-147984

  However, due to reasons such as improving the productivity of hydraulic powder, improving the productivity of secondary concrete products, and improving the strength of the hardened concrete, the method for producing hydraulic powder provides the pulverizability of the hydraulic compound. Further improvement is desired in both the compressive strength at the time of curing of the hydraulic composition using the hydraulic powder.

  The problem of the present invention is that the pulverization efficiency of the hydraulic compound is good, that is, it is possible to shorten the time to reach the desired particle size, and the compressive strength (24 when the obtained hydraulic composition is cured). It is to provide a method for producing a hydraulic powder that is compatible with obtaining a hydraulic powder such as cement that improves time and 7 days). For example, the compressive strength when cured after 24 hours is an indicator of the time at which demolding is possible, for example, related to the production cycle of a secondary concrete product. It is an index related to the hardening strength to reach.

  The inventor uses glycerin monoacetate ester and N-methyldiethanolamine in combination as a grinding aid to greatly improve both the grindability of the hydraulic compound and the compressive strength during curing of the hydraulic composition. I found out.

  The present invention relates to a method for producing hydraulic powder, which comprises a step of pulverizing a hydraulic compound in the presence of glycerin monoacetate and N-methyldiethanolamine.

Further, the present invention is a hydraulic powder obtained by the production method of the present invention, wherein a specific surface area (hereinafter referred to as a brane value) measured by a Blaine specific surface area measurement method is 2000 to 5000 cm ² / g. It relates to a certain hydraulic powder.

  The present invention also relates to a grinding aid for hydraulic compounds containing glycerin monoacetate and N-methyldiethanolamine.

  According to the present invention, by using glycerin monoacetate (monoacetin) and N-methyldiethanolamine in combination, the grinding efficiency of the hydraulic compound is good, that is, the time to reach the desired particle size is shortened. There is provided a method for producing a hydraulic powder that is compatible with the fact that it can be obtained and that a hydraulic powder such as cement that improves the compressive strength during curing of the resulting hydraulic composition is obtained.

  There are two reasons why the grindability is improved by the grinding aid. The first reason is to suppress electrostatic aggregation (agglomeration) of the material to be crushed, and the second reason is dehydration from moisture in the air, diluting water of the grinding aid, and added dihydrate gypsum crystal water. It is a point which suppresses the liquid bridge | crosslinking by which to-be-ground particles aggregate through the water | moisture content by the etc.

  The mechanism for producing the effect of the present invention is unknown, but is estimated as follows. That is, the glycerin monoacetate ester and N-methyldiethanolamine according to the present invention are present when pulverizing the hydraulic compound, so that a desired particle size can be obtained in a shorter time than a conventional pulverization aid. Can be pulverized. Since glycerin monoacetate and N-methyldiethanolamine have different coating areas on the fracture surface of the object to be crushed, by using these compounds in combination, the gaps are complementarily filled, and the fracture surface of the object to be crushed can be made without any gaps. It is presumed that the molecules can be arranged. In addition, glycerin monoacetate and N-methyldiethanolamine both have hydrophobic methyl groups, and by orienting the methyl groups outward from the surface of the material to be crushed at an appropriate interval, liquid crosslinking due to moisture is suppressed. Is estimated to be more effective. By covering the fracture surface of the material to be crushed without gaps and methyl groups (hydrophobic groups) oriented outward from the surface of the material to be crushed, both electrostatic agglomeration and liquid cross-linking due to moisture are suppressed. It is estimated that the grinding efficiency is improved.

  On the other hand, regarding the improvement of the compressive strength at the time of hardening of the hydraulic composition, in order to improve the initial compressive strength for 24 hours from water contact, the porosity in the hydrated product is reduced and the hydrated product is constituted. It is estimated that densification of the crystal structure is effective. In addition, since this crystal structure is the foundation of the hydration reaction in the cement hydration composition that continues for a long period of time, it will affect the subsequent hydration crystal structure, and hence the compressive strength of the cement for more than 7 days. Presumed.

The glycerin monoacetate according to the present invention undergoes hydrolysis in the cement hydration system, whereby glycerin and acetic acid are generated. Glycerin promotes the formation of ettringite, a hydrated product composed of C ₃ A, C ₄ AF and gypsum, which are minerals contained in cement, and acetic acid gradually lowers the pH of cement hydrated water. Thus, it is considered that the production of monosulfate, which is a hydrated product composed of ettringite and C ₃ A, is promoted. Ettringite greatly reduces the porosity in the cement hydrated product due to the entanglement of the long needle-like crystals, and monosulfate improves the compactness of the crystal structure constituting the cement hydrated product due to the lamination of the dense hexagonal plate crystals. Greatly improve. It is presumed that the compressive strength after 24 hours and 7 days after contact with the cement is improved by more efficiently producing these cement hydrates.

  N-methyldiethanolamine promotes the dissolution of gypsum and promotes the production of ettringite by an alkanolamine skeleton having an appropriate calcium ion scavenging ability (pKCa). This dissolution promotion effect of gypsum is considered to work synergistically with the ettringite production promotion effect of glycerol derived from glycerol monoacetate described above. Due to the efficient production reaction of ettringite, the subsequent monosulfate production reaction is also started early, and the production amount in 24 hours after contact with the cement is increased. At this time, it is considered that the monosulfate production promoting action of acetic acid derived from glycerin monoacetate described above works synergistically. As a result of these actions acting synergistically, the reduction in porosity and the improvement of the compactness in the cement hydrate are achieved more efficiently, and the compressive strength is improved 24 hours and 7 days after the cement contacts the water. It is estimated that.

  A commercial item can be used for the glycerol monoacetic acid ester which concerns on this invention. In glycerol diacetate ester and glycerol triacetate ester with many ester groups in a molecule | numerator, there exists a tendency for the improvement of the grindability of a hydraulic compound and the improvement of compressive strength to be inferior.

  At the time of pulverizing the hydraulic compound, water can be added to adjust the viscosity of the liquid containing glycerin monoacetate. Moreover, it is excellent also in the mixability with the water at the time of mixing the hydraulic powder manufactured by this invention with water, and preparing a hydraulic composition.

  A commercial item can be used for N-methyldiethanolamine which concerns on this invention. N-methyldiethanolamine can be used as a salt from the viewpoint of enhancing the solubility in water. Salts include mixtures of salts selected from sulfates, acetates, chloride salts, formates, carbonates, silicates, hydroxide salts and mixtures thereof. By improving the water solubility of N-methyldiethanolamine, it is possible to improve the handleability. In addition, when using the alkanolamine which concerns on this invention as a salt, the weights, such as the usage-amount mentioned later, are not the weight of the salt itself, but the weight in terms of amine, that is, the weight in terms of N-methyldiethanolamine.

  In the present invention, the weight ratio of glycerin monoacetate and N-methyldiethanolamine is such that the grindability of the hydraulic compound is improved and the compressive strength at the time of curing of the resulting hydraulic composition is improved. The weight ratio of acetate / N-methyldiethanolamine is preferably 2/8 to 8/2, more preferably 3/7 to 7/3, still more preferably 4/6 to 6/4, and 4.5 / 5. 5 to 5.5 / 4.5 is even more preferable. Moreover, from the viewpoint of improving the compressive strength after 7 days at the time of curing the hydraulic composition, the weight ratio of glycerin monoacetate / N-methyldiethanolamine is preferably 1/9 to 7/3, and 2/8 to 7 / 3 is more preferable, 2/8 to 4/6 is still more preferable, and 2.5 / 7.5 to 3.5 / 6.5 is still more preferable.

  Since the mixture of glycerin monoacetate and N-methyldiethanolamine according to the present invention is usually liquid at room temperature, for example, 20 ° C., the workability such as weighing and adding operation when using a hydraulic compound for grinding is improved. It is excellent. Glycerin monoacetate and N-methyldiethanolamine can be used as a liquid having a concentration of 100% by weight, but may be used as an aqueous solution from the viewpoint of facilitating handling. In this case, the concentration of glycerin monoacetate and N-methyldiethanolamine in the aqueous solution is preferably 30 to 99% by weight in an aqueous solution of glycerin monoacetate, an aqueous solution of N-methyldiethanolamine, and a mixture thereof. 99 weight% is more preferable and 50-99 weight% is still more preferable. The mixture is preferably used as it is (concentration 100%) or as an aqueous solution at a concentration of 30 to 99% by weight, more preferably 40 to 99% by weight, and further 50 to 99% by weight.

In the method for producing hydraulic powder of the present invention, a hydraulic compound is pulverized to obtain hydraulic powder. A hydraulic compound is a substance that has the property of curing by reacting with water, and a single substance does not have curability, but when two or more are combined, a hydrate is formed by interaction through water and cured. Refers to a compound. In general, hydraulic compounds include alkaline earth metal oxides and oxides such as SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , TiO ₂ , P ₂ O ₅ , and ZnO hydrate at room temperature or hydrothermal conditions. Form things. Examples of hydraulic compounds include minerals (C ₃ S, C ₂ S, C ₃ A, C ₄ AF), slag, fly ash, limestone, iron slag, gypsum, alumina, incinerated ash, etc. contained in cement. And can be used as a raw material for hydraulic powders.

Also, as mineral contained in the hydraulic powder, e.g., in _{cement, 3CaO · SiO 2 (C 3} S: _{alite), 2CaO · SiO 2 (C} 2 S: _{belite), 3CaO · Al 2 O 3} ( C ₃ A: calcium aluminate), 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ (C ₄ AF: calcium aluminoferrite), and hydraulic compounds containing these components can be used.

From the viewpoint of improving grindability of the hydraulic compound and improving the compressive strength of the cured product of the hydraulic composition, the content of C ₃ A in the obtained hydraulic compound powder is preferably 0.5 to 9.5% by weight, More preferably, the components of the hydraulic compound are adjusted so as to be 1.0 to 9.0% by weight. In order to make the content of C ₃ A as a pore to C ₃ S and C ₂ S of the hydraulic compound within the above range in the hydraulic powder after pulverization, for example, a firing step in the production of the hydraulic compound And a method of firing the raw material of the hydraulic compound (for example, clinker) at 1250 ° C. or higher, preferably 1300 to 1450 ° C., more preferably 1350 to 1450 ° C. Furthermore, from the viewpoint of improving the compressive strength of the cured product of the hydraulic composition, the content of C ₄ AF in the obtained hydraulic powder is preferably 11% by weight or less, more preferably 0.1 to 10% by weight. , Even more preferably. It is preferable to adjust the components of the hydraulic compound so as to be 1 to 9.5% by weight. The contents of C ₃ A and C ₄ AF in the hydraulic powder are measured by the method of quantifying each mineral shown in the examples.

The effect of improving pulverization in the presence of N-methyldiethanolamine and glycerin monoacetate according to the present invention is presumed to be due to the mechanism described above, but if the content of pores such as C ₃ A increases, the pulverization step Is governed by mechanical force, and it is assumed that the difference due to the difference in the compound used for the grinding aid is reduced. Further, when the hydraulic composition is cured, it is presumed that the curing reaction between C ₃ A and gypsum and the like is promoted by an appropriate chelating action of N-methyldiethanolamine and glycerol monoacetate according to the present invention.

When obtaining Portland cement as hydraulic powder, for example, Portland cement is a clinker (also called cement clinker, which is a hydraulic compound obtained by firing raw materials such as limestone, clay, iron dies, etc., and contains gypsum. If the sometimes) pre-ground, gypsum is added if necessary, finish grinding, Blaine value 2000 cm ² / g or more, are preferably produced as a powder having the above specific surface area 2500 cm ² / g. The glycerin monoacetate and N-methyldiethanolamine according to the present invention are preferably used as a grinding aid for the hydraulic compound, preferably clinker grinding. The glycerin monoacetate and N-methyldiethanolamine according to the present invention are preferably used as grinding aids in finish grinding.

  From the viewpoint of pulverizing to a desired particle size in a short time, glycerin monoacetic acid ester is 0.0005 to 0.1 parts by weight based on 100 parts by weight of a hydraulic compound used for pulverization, for example, cement clinker. .0025 to 0.05 parts by weight, further 0.005 to 0.04 parts by weight, further 0.010 to 0.030 parts by weight, and further 0.018 to 0.025 parts by weight. preferable. In addition, glycerol monoacetate is used in an amount of 0.010 to 0.030 parts by weight with respect to 100 parts by weight of a hydraulic compound, for example, a cement clinker, from the viewpoint of improving the compressive strength after 24 hours during curing of the hydraulic composition. It is preferable to use it so that it may become 0.018-0.025 weight part more. In addition, the glycerin monoacetic acid ester is 0.005 to 0.030 parts by weight with respect to 100 parts by weight of a hydraulic compound, for example, a cement clinker, from the viewpoint of improving the compressive strength after 7 days of curing the hydraulic composition. It is preferable to use it so that it may become 0.010-0.015 weight part. In addition, glycerin monoacetate is a raw material water used for pulverization from the viewpoint of pulverizing to a desired particle size in a short time, and improving compressive strength after 24 hours and 7 days after curing of the hydraulic composition. Hard compounds such as 0.005 to 0.04 parts by weight, more preferably 0.010 to 0.030 parts by weight, and even more preferably 0.010 to 0.025 parts by weight with respect to 100 parts by weight of cement clinker. Is preferred.

  From the viewpoint of pulverizing to a desired particle size in a short time, N-methyldiethanolamine is 0.0005 to 0.10 parts by weight with respect to 100 parts by weight of a hydraulic compound as a raw material used for pulverization, for example, 0 to 0 parts by weight. .0025 to 0.05 parts by weight, further 0.005 to 0.04 parts by weight, further 0.010 to 0.030 parts by weight, and further 0.015 to 0.022 parts by weight. preferable. Moreover, N-methyldiethanolamine is 0.010-0.030 weight part with respect to 100 weight part of hydraulic compounds, for example, cement clinker from a viewpoint of an improvement of the compressive strength after 24 hours at the time of hardening of a hydraulic composition, It is preferable to use it so that it may become 0.015-0.022 weight part. Moreover, N-methyldiethanolamine is 0.010-0.035 weight part with respect to 100 weight part of hydraulic compounds, for example, a cement clinker from a viewpoint of the improvement of a compressive strength after 7 days at the time of hardening of a hydraulic composition. It is preferable to use it so that it may become 0.025-0.030 weight part. N-methyldiethanolamine is a raw material water used for pulverization from the viewpoint of pulverizing to a desired particle size in a short time, and improving compressive strength after 24 hours and 7 days after curing of the hydraulic composition. Hard compounds such as 0.005 to 0.04 parts by weight, more preferably 0.010 to 0.030 parts by weight, and even more preferably 0.015 to 0.030 parts by weight with respect to 100 parts by weight of cement clinker. Is preferred.

  The total amount of glycerin monoacetate and N-methyldiethanolamine is 0.001 to 0.2 parts by weight in terms of the total solid content with respect to 100 parts by weight of the raw hydraulic compound used for pulverization, for example, cement clinker. 0.005 to 0.1 parts by weight, 0.01 to 0.08 parts by weight, 0.020 to 0.060 parts by weight, and 0.033 to 0.047 parts by weight. From the viewpoint of grinding to a desired particle size in a short time. The total amount of glycerin monoacetate and N-methyldiethanolamine is a total solid content with respect to 100 parts by weight of a hydraulic compound, for example, a cement clinker, from the viewpoint of improving the compressive strength after 24 hours at the time of curing the hydraulic composition. It is preferable to use 0.020 to 0.060 parts by weight, more preferably 0.033 to 0.047 parts by weight. The total amount of glycerin monoacetate and N-methyldiethanolamine is 0.015 with respect to 100 parts by weight of a hydraulic compound, for example, a cement clinker, from the viewpoint of improving compressive strength after 7 days of curing the hydraulic composition. It is preferable to use it so that it may become -0.065 weight part, and 0.035-0.045 weight part more. In addition, the total amount of glycerin monoacetate and N-methyldiethanolamine is from the viewpoint of pulverizing to a desired particle size in a short time, from the viewpoint of improving compressive strength after 24 hours and 7 days after curing of the hydraulic composition. , Starting material hydraulic compound used for pulverization, for example, 0.010 to 0.08 parts by weight, more 0.020 to 0.060 parts by weight, and further 0.025 to 0.055 parts by weight based on 100 parts by weight of cement clinker It is preferable to use it so that it may become a weight part.

  As a method of grinding in the presence of glycerin monoacetate and N-methyldiethanolamine, it is preferable to add a mixture of glycerin monoacetate and N-methyldiethanolamine to a raw material containing a hydraulic compound such as clinker. Examples of the method of addition include a method of supplying the mixture or a mixture containing the mixture and other components, preferably in the form of an aqueous solution, by dropping, spraying, or the like. Examples of other components include known anti-foaming agents, water, glycerin monoacetate, and known grinding aids other than N-methyldiethanolamine. As for the addition of the mixture to the raw material containing the hydraulic compound, the total amount finally used may be added all at once, or may be added in divided portions. Moreover, you may supply and add continuously or intermittently. Moreover, you may add glycerol monoacetic acid ester and N-methyldiethanolamine separately.

In the method for producing hydraulic powder according to the present invention, the pulverization conditions may be adjusted so that a powder having an appropriate particle size can be obtained depending on the raw material, use, and the like. Compressive strength upon curing of the resultant hydraulic powder, and from the viewpoint of production cost, the specific surface area, i.e. the Blaine value of the resultant hydraulic powder has the 2000~5000cm ² / g Preferably, 2500~5000cm ² / g Is more preferable, and 3000-4000 cm < ² > / g is still more preferable. It is preferable to grind a hydraulic compound such as a clinker until the specific surface area becomes a powder satisfying the above range. The target brain value can be obtained, for example, by adjusting the grinding time. When the pulverization time is lengthened, the brane value tends to increase, and when shortened, the brane value tends to decrease.

  In the present invention, the pulverizing apparatus used for pulverizing the hydraulic compound is not particularly limited, and examples thereof include a ball mill which is widely used for pulverizing cement and the like. The material of the grinding media (grinding balls) of the apparatus is preferably one having a hardness equal to or higher than that of the material to be ground (for example, calcium aluminate in the case of cement clinker). Steel, stainless steel, alumina, zirconia, titania, tungsten carbide and the like can be mentioned.

  The hydraulic powder obtained by the production method of the present invention is a hydraulic powder with a total amount of glycerin monoacetate and N-methyldiethanolamine as a solid content from the viewpoint of improving the compressive strength when the hydraulic composition is cured. In the body, 0.0005 to 0.5% by weight, more 0.0025 to 0.2% by weight, further 0.005 to 0.1% by weight, still more 0.010 to 0.060% by weight, still more 0 It is preferable to contain 0.015-0.047 weight%.

Further, the hydraulic powder obtained by the production method of the present invention has a C ₃ A content of 0.5 to 9 in the hydraulic powder from the viewpoint of improving the compressive strength of the cured product of the hydraulic composition. 0.5% by weight is preferable, and 1.0 to 9.0% by weight is more preferable. Furthermore, from the viewpoint of improving the compressive strength of the cured product of the hydraulic composition, the content of C ₄ AF in the hydraulic powder is 11% by weight or less, further 0.1 to 10% by weight, and further 0.1 to 9%. It is preferably 5% by weight. The contents of C ₃ A and C ₄ AF in the hydraulic powder are measured by the method of quantifying each mineral shown in the examples.

  Glycerol monoacetate and N-methyldiethanolamine according to the present invention are used for grinding hydraulic compounds as grinding aids for hydraulic compounds, have good grinding efficiency, and improve the compressive strength of hydraulic compositions. Can do.

  When an aqueous solution containing glycerin monoacetate and N-methyldiethanolamine is used as the grinding aid for the hydraulic compound, the concentration of glycerin monoacetate and N-methyldiethanolamine in the aqueous solution is preferably 30 to 99 weights. %, More preferably 40 to 99% by weight, still more preferably 50 to 99% by weight. In the case of using an aqueous solution containing glycerin monoacetate and N-methyldiethanolamine, 100 weight of the hydraulic compound is used from the viewpoint of workability such as weighing and adding operation when using the grindability of the hydraulic compound and grinding of the hard compound. The amount of water in the aqueous solution is preferably 0.001 to 0.1 parts by weight, more preferably 0.001 to 0.08 parts by weight, and 0.001 to 0.05 parts by weight with respect to parts. More preferably.

  An antifoaming agent can be used in combination from the viewpoint of suppressing strength reduction due to an increase in the amount of air in the hydraulic composition. Moreover, by making an antifoamer exist at the time of the grinding | pulverization of a hydraulic compound, an antifoamer can be uniformly distributed on the surface of the hydraulic powder obtained, and the said inhibitory effect can also be expressed more effectively.

  As the antifoaming agent, a silicone-based antifoaming agent, a fatty acid ester-based antifoaming agent, and an ether-based antifoaming agent are preferable. In the silicone-based antifoaming agent, dimethylpolysiloxane is more preferable, and in the fatty acid ester-based antifoaming agent, polyalkylene glycol. Fatty acid esters are more preferred, and polyalkylene glycol ethers are more preferred for ether-based antifoaming agents.

  The weight ratio of the total amount (a) of glycerin monoacetate and N-methyldiethanolamine to the amount (b) of the antifoaming agent is such that (a) / (b) = 99/1 to 50/50 is preferable, 97/3 to 60/40 is more preferable, and 95/5 to 70/30 is more preferable. The weight ratio of glycerin monoacetate and N-methyldiethanolamine (a) to the antifoaming agent (b) is calculated in terms of effective content (solid content).

  The hydraulic composition using the hydraulic powder obtained by the production method of the present invention has improved compressive strength. Examples of the hydraulic powder include Portland cement, blast furnace slag, alumina cement and other cements, fly ash, limestone, and gypsum.

  The hydraulic powder obtained by the production method of the present invention can be used as a material for concrete structures and concrete products. Since the concrete using the hydraulic powder obtained by the production method of the present invention has improved compressive strength after 24 hours and 7 days from water contact, for example, the hydraulic powder obtained by the production method of the present invention Even if hydraulic powder with low initial age strength after contact with water (blast furnace slag, fly ash, limestone, etc.) is added to the body, it is compared with the case of using hydraulic powder not yet implemented in the present invention. And, it has advantages such as being able to obtain compressive strength after 24 hours and 7 days, which is equal to or higher than that.

(Examples 1-8 and Comparative Examples 1-11)
The following materials are used in the following blending amounts, charged in a lump and pulverized by a ball mill (crushing time to reach the target brain value), and hardening of the hydraulic composition using the resulting cement The compression strength test at the time was evaluated as follows. The results are shown in Table 1.

(1-1) Materials used clinker: components, CaO: about 68%, SiO _2: about 25%, Al ₂ O _3: about 4%, MgO other: to be about 3% (by weight), Ordinary Portland cement clinker obtained by primary pulverization of limestone, clay, silica, etc. by crusher and grinder
Dihydrate gypsum: dihydrate gypsum with an amount of SO ₃ of 45.93% by weight and grinding aid: See Table 1.

(1-2) Compounding amount / clinker: 1000 g
Dihydrate gypsum: 52.3 g (2.4 parts by weight of SO _{3 with} respect to 100 parts by weight of clinker)
Grinding aid: parts by weight of the compounds in Table 1 shown in Table 1. For the addition, a 50% by weight aqueous solution was used.

The contents of C ₃ S, C ₂ S, C ₃ A and C ₄ AF in the hydraulic powder obtained by the above blending were 49.5% by weight, 42.2% by weight and 4.5%, respectively. % By weight and 0.2% by weight.

The minerals in the hydraulic powder were quantified by the following method. As a powder X-ray apparatus, RINT-2500 (manufactured by Rigaku Corporation) is used. As measurement conditions, target CuKα, tube current 40 mA, tube voltage 200 kV, scanning range 5 to 70 ° .2θ, scanning conditions are step scanning, step width. The setting was 0.02 ° and the counting time was 2 seconds. Then, 0.3 g of the standard substance “α-corundum (Al ₂ O ₃ )” was added to 2.7 g of the hydraulic powder of the sample, and quantified with Rietveld analysis software based on the peak area of the standard substance. As Rietveld analysis software, PDXL Ver.1.8 manufactured by Rigaku Corporation was used.

(1-3) Ball mill AXB-15 manufactured by Seiwa Giken Co., Ltd., stainless steel pot capacity of 18 liters (outer diameter 300 mm), stainless steel balls 30 mmφ (nominal 1/4), 20 mmφ (nominal 3 / 4), a total of 100 70 pieces, and the rotation speed of the ball mill was set to 35 rpm. A part of the pulverized material was discharged during sampling and sampled.

(1-4) a milling arrival time target Blaine value and 3300 ± 100cm ² / g, 60 minutes from the start grinding, 75 minutes, measure the Blaine values for the sample after 90 minutes, reaches the target Blaine value 3300 cm ² / g The time was determined by a quadratic regression equation of Microsoft Excel 2003 manufactured by Microsoft Corporation. Crushing was finished with the time as the final arrival time (crushing arrival time) to obtain cement. The total amount of glycerin fatty acid ester (monoacetin) and N-methyldiethanolamine in the cement is 0.02% by weight (Example 7) and 0.04% by weight (Examples 1 to 6) calculated from the amount of raw materials used. ) And 0.08% by weight (Example 8). For the measurement of the brane value, a brane air permeation device defined in a physical test method for cement (JIS R 5201) was used. The difference in the crushed arrival time in this test becomes a larger difference at the actual machine level. The shorter the pulverization time, the better the pulverizability.

(1-5) Compressive strength test

The compressive strength was measured in accordance with Cement Physical Test Method (JIS R 5201), Annex 2 (Cement Test Method-Strength Measurement). The cement used has a brain value of 3300 ± 100 cm ² / g obtained above. From the viewpoint of manufacturing a concrete product or a structure, it is desirable that the compressive strength is larger.

Monoacetin: Glycerol monoacetate (manufactured by Wako Pure Chemical Industries, Ltd., reagent)
M-DEA: N-methyldiethanolamine (Nippon Emulsifier Co., Ltd., amino alcohol MDA)
・ TiPA: Triisopropanolamine (Wako Pure Chemical Industries, Ltd.)
DEA: Diethanolamine (Sigma Aldrich)
-TEA: Triethanolamine (manufactured by Sigma-Aldrich)
・ T-Bu-DEA (Wako Pure Chemical Industries, Ltd.)
・ Diacetin: (Wako Pure Chemical Industries, Reagent)
・ Triacetin: (Wako Pure Chemical Industries, Reagent)

From Table 1, it can be seen that by using glycerin monoacetate and N-methyldiethanolamine in combination, both the pulverization efficiency and the compressive strength are greatly improved as compared with the case where the same amount is used alone. The values in Table 1 are relative values with the reference value (100) when no grinding aid is used. For reference, the absolute value of the standard pulverization arrival time is 135 minutes, the absolute value of the compressive strength is 12.7 N / mm ² of the average value of the standard values after 24 hours (N = 10), and the standard value after 7 days. The average value (N = 10) was 34.8 N / mm ² .

(Example 9 and Comparative Examples 12 to 13)
Further, the contents of C ₃ S, C ₂ S, C ₃ A, C ₄ AF and gypsum in the hydraulic powder were 63.1 wt%, 16.2 wt%, 8.6 wt%, 8 Using 0.5 wt% nominal 3.6 wt% hydraulic powder, the pulverization time, compressive strength after 24 hours and after 7 days were evaluated in the same manner as in Example 1. The results are shown in Table 2. The values in Table 2 are relative values with the reference value (100) when no grinding aid is used. For reference, the absolute value of the standard pulverization arrival time is 143 minutes, the absolute value of the compressive strength is 11.5 N / mm ² of the average value of the reference values after 24 hours (N = 10), and the reference value after 7 days. The average value (N = 10) was 40.9 N / mm ² .

Claims (3)

A method for producing a hydraulic powder comprising a step of pulverizing a hydraulic compound in the presence of glycerin monoacetate and N-methyldiethanolamine,
The weight ratio of glycerin monoacetate and N-methyldiethanolamine in the above process is 2/8 to 8/2 in terms of weight ratio of glycerin monoacetate / N-methyldiethanolamine.
A method for producing hydraulic powder. The method for producing a hard powder according to claim 1, wherein the total amount of glycerin monoacetate and N-methyldiethanolamine is 0.001 to 0.2 parts by weight with respect to 100 parts by weight of the hydraulic compound. Water containing glycerin monoacetate and N-methyldiethanolamine, wherein the weight ratio of glycerin monoacetate to N-methyldiethanolamine is glycerin monoacetate / N-methyldiethanolamine and is 2/8 to 8/2. A grinding aid for hard compounds.