JP5805442B2 - 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.

  Glycerin is used as a grinding aid for hydraulic compounds. For example, in Patent Document 1, untreated glycerin is used as a cement additive to improve the compressive strength of cement, and the untreated glycerin contains 1 to 10% alkali metal inorganic salt in weight%. It is described that It is described that the untreated glycerin can be added during the clinker grinding treatment.

  In addition, there is a technique using an inorganic salt in order to improve the 7-day strength and 28-day strength of concrete. For example, Patent Document 2 describes a strength-enhancing additive composed of a higher trialkanolamine and a water-soluble alkali metal salt, and this additive may be a mixture with cement powder, and during finishing mill processing. Describes that mutual grinding with a cement clinker is also possible.

  Patent Document 3 discloses that (A) a polyhydric alcohol and an alkylene oxide adduct of a polyhydric alcohol are selected in order to improve the grinding efficiency and the strength of the hydraulic composition produced from the obtained hydraulic powder. In the presence of a compound (a) obtained by reacting one or more of the above and (B) a sulfating agent, hydraulic powder is produced through a step of pulverizing the hydraulic compound.

Special table 2008-519752 gazette Japanese Patent Laid-Open No. 3-183647 JP 2010-42986 A

  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 concrete hardened body, the hydraulic property of the grinding aid such as glycerin in the manufacturing method of hydraulic powder It is desired to further improve the compressive strength at the time of curing of the hydraulic composition using the obtained hydraulic powder without reducing the grindability of the compound.

  An object of the present invention is to provide a hydraulic powder such as cement for improving the compressive strength (the compressive strength after 24 hours after the hydraulic powder comes into contact with water, hereinafter referred to as the strength for 24 hours) when the hydraulic composition is cured. It is providing the manufacturing method of the hydraulic powder from which is obtained. For example, the 24-hour strength is an indicator of the demoldable time associated with the concrete secondary product production cycle.

  The inventor added an alkali metal sulfate salt to a hydraulic compound together with glycerin and / or glycerin monoacetate as a grinding aid, without reducing the grindability of the grinding aid, It has been found that the compressive strength during curing of a hydraulic composition using the obtained hydraulic powder is greatly improved.

  The present invention relates to the production of a hydraulic powder that is pulverized by adding one or more compounds A selected from glycerin and glycerin monoacetate [hereinafter referred to as compound A] and alkali metal sulfate B to the hydraulic compound. Regarding the method.

  According to the present invention, glycerin and / or glycerin monoacetate and an alkali metal sulfate salt are added and pulverized, so that the pulverization property of the hydraulic compound of the pulverization aid such as glycerin can be reduced. There is provided a method for producing a hydraulic powder from which a hydraulic powder such as cement that improves the compressive strength during curing of the hydraulic composition is obtained.

  In the present invention, glycerin and / or glycerin monoacetate and alkali metal sulfate are added at the time of grinding the hydraulic compound, so that glycerin and / or glycerin monoacetate and alkali metal sulfate are hydraulic powder. It adheres evenly to the surface. At the time of kneading the hydraulic powder and water, since glycerin and / or glycerin monoacetate and alkali metal sulfate salt are present in the vicinity of each other, the hydration reaction of the mineral constituting the hydraulic powder is promoted efficiently, It is estimated that the strength improvement effect can be expressed effectively. And even if an alkali metal sulfate salt is present during the pulverization of the hydraulic compound, it does not hinder the improvement of the pulverization efficiency by glycerin or glycerin monoacetic acid ester. An advantageous effect will be obtained.

  On the other hand, after obtaining a hydraulic powder using glycerin and / or glycerin monoacetate, which is a grinding aid, when mixed with an alkali metal sulfate, glycerin or glycerin monoacetate is added to the surface of the hydraulic powder. However, some alkali metal sulfates are locally attached to the surface of the hydraulic powder, and some are not attached to the hydraulic powder. As a result, at the time of kneading the obtained hydraulic powder and water, glycerin or glycerin monoacetic acid ester and alkali metal sulfate sulfate are less likely to exhibit a coordinated effect, so the degree of improvement in curing strength is inferior. It is estimated to be.

  Regarding the action of glycerin or glycerin monoacetate and alkali metal sulfate, glycerin and / or glycerin monoacetate promotes the elution of calcium ions in hydraulic powder, and the hydration rate of hydraulic powder and It is presumed that both the hydration reaction rate is improved, and the generation of hydrated crystal minerals containing sulfate ions is promoted and the hardening strength is improved by the moderate presence of sulfate ions generated from alkali metal sulfates. .

  Furthermore, alkali metal ions generated from alkali metal sulfates have a hydration reaction rate by breaking the gel layer generated on the surface of the hydraulic powder generated by the hydration reaction when kneading the hydraulic powder and water. It is estimated that the cured strength is improved.

  Commercially available glycerin and glycerin monoacetate of Compound A can be used. As glycerin, commercially available refined glycerin, for example, glycerin obtained by transesterification of oil derived from palm can be used. In addition, rough brine obtained by hydrolysis of beef tallow and vegetable oil, purified brine obtained by removing impurities from coarse brine, and the like can be used. From the viewpoint of improving the 24-hour strength and the 7-day strength, rough brine and purified glycerin are preferable, and purified glycerin is more preferable.

  As the alkali metal sulfate B, a commercially available product can be used. Examples of the alkali metal sulfate B include sodium sulfate, potassium sulfate and lithium sulfate. Among these, sodium sulfate is preferably used from the viewpoint of improving the strength for 24 hours and the strength for 7 days.

  Compound A is added in an amount of 0.01 to 1 with respect to 100 parts by weight of a raw material hydraulic compound used for pulverization, for example, cement clinker, from the viewpoint of improvement of pulverization and improvement of 24 hour strength and 7 day strength. .50 parts by weight, more preferably 0.02 to 1.50 parts by weight, more preferably 0.04 to 1.00 parts by weight, and more preferably 0.11 to 0.70 parts by weight. Is more preferable. In addition, from the viewpoint of improving grindability, Compound A is used in an amount of 0.04 parts by weight or more, and further 0.11 parts by weight or more with respect to 100 parts by weight of a hydraulic compound as a raw material used for grinding. It is preferably 1.20 parts by weight or less, more preferably 0.60 parts by weight or less, still more preferably 0.50 parts by weight or less, and even more preferably 0.25 parts by weight or less. Further, from the viewpoint of improving the strength for 24 hours and 7 days, the compound A is preferably 0.12 parts by weight or more with respect to 100 parts by weight of a hydraulic compound as a raw material used for pulverization, for example, cement clinker. 15 parts by weight or more is more preferable, and 0.35 parts by weight or more is still more preferable. Moreover, 1.80 weight part or less is preferable, 1.40 weight part or less is more preferable, 1.20 weight part or less is still more preferable.

  Moreover, the addition amount of the alkali metal sulfate B is 0.02 to 2 with respect to 100 parts by weight of a raw material hydraulic compound used for pulverization, for example, cement clinker, from the viewpoint of improving the strength for 24 hours and 7 days. 0.0 part by weight is preferable, 0.12 to 1.7 part by weight is more preferable, 0.25 to 0.95 part by weight is still more preferable, and 0.35 to 0.80 part by weight is still more preferable.

  From the viewpoint of improving the strength for 24 hours and the strength for 7 days, the total amount of the compound A and the alkali metal sulfate B added is the sum of the amount of the raw material hydraulic compound used for grinding, for example, 100 parts by weight of cement clinker. The solid content is preferably 0.04 to 3.5 parts by weight, more preferably 0.14 to 3.2 parts by weight, still more preferably 0.30 to 2.00 parts by weight, and 0.40 to 1.80 parts by weight. Is more preferable, and 0.65 to 1.30 parts by weight is even more preferable.

  In the present invention, from the viewpoint of improving the grindability of the hydraulic compound, the weight ratio of compound A to alkali metal sulfate B is preferably compound A / alkali metal sulfate B, preferably 0.1 or more, 0.2 The above is more preferable, and 1.0 or more is still more preferable. Further, from the viewpoint of improving the strength for 24 hours and the strength for 7 days, the weight ratio of the compound A and the alkali metal sulfate B is preferably 10 or less, more preferably 8.0 or less in the compound A / alkali metal sulfate B. Preferably, it is 2.0 or less, more preferably 1.0 or less, still more preferably 0.3 or less, and even more preferably 0.2 or less. From the above two viewpoints, the weight ratio between the compound A selected from glycerin and glycerin monoacetate and the alkali metal sulfate B is compound A / alkali metal sulfate B, preferably 0.1 to 8.0, 0.1-2.0 are more preferable, 0.2-1.0 are still more preferable, and 0.2-0.3 are still more preferable.

  The compound A according to the present invention is usually excellent in workability such as weighing and addition operation when the hydraulic compound is used for pulverization because the mixture is liquid at normal temperature, for example, 20 ° C. Compound A 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 total concentration of Compound A in the aqueous solution is preferably 30 to 99% by weight, more preferably 40 to 99% by weight, and still more preferably 50 to 99% by weight.

  In the case of using an aqueous solution containing Compound A, from the viewpoint of workability such as weighing and addition operation, etc. when used for pulverization of the hydraulic compound and pulverization of the hard compound, the said relative to 100 parts by weight of the hydraulic compound The amount of water in the aqueous solution is preferably 0.001 to 2.0 parts by weight, more preferably 0.005 to 1.0 parts by weight, and further 0.001 to 0.50 parts by weight. preferable.

  The alkali metal sulfate B according to the present invention is usually in a powder form. When using a hydraulic compound for grinding | pulverization, it can add with a powder similarly to the gypsum added.

  In the present invention, since compound A and alkali metal sulfate B prepared separately can be added at the time of pulverization, adjustment of the amount added to the hydraulic group compound, adjustment of the weight ratio of compound A and alkali metal sulfate B, etc. Becomes easy.

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 the hydraulic compound include minerals contained in cement (C ₃ S, C ₂ S, C ₃ A, C ₄ AF), slag, fly ash, limestone, iron slag, alumina, incineration ash, and the like. It can be used as a raw material for hydraulic powder.

When obtaining Portland cement as a hydraulic powder, for example, Portland cement preliminarily grinds a clinker, which is a hydraulic compound obtained by firing raw materials such as limestone, clay, iron slag, etc. In addition, it is finely pulverized to produce a powder having a specific surface area of a brain value of 2500 cm ² / g or more.

  The compound A and the alkali metal sulfate B according to the present invention are preferably used as a grinding aid for the hydraulic compound, preferably clinker grinding. Moreover, it is preferable to use the compound A and the alkali metal sulfate B according to the present invention as a grinding aid in finish grinding.

  As a method of adding compound A and alkali metal sulfate B to pulverize, compound A (preferably as an aqueous solution) and alkali metal sulfate B (preferably in powder form) are added to a raw material containing a hydraulic compound, for example, clinker. And do it. In addition, although the alkali metal sulfate salt B can be mix | blended with this aqueous solution, it is preferable to attach separately from the aqueous solution from a viewpoint of the solubility to the water of the alkali metal sulfate B salt.

  As other components, antifoaming agents, water, known grinding aids other than Compound A, and the like may be added.

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, Blaine value is preferably 2000~5000cm ² / g, more preferably 2500~5000cm ² / g, 3000~4000cm ² / g is 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.

  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 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. The concrete using the hydraulic powder obtained by the production method of the present invention is improved in strength for 24 hours and 7 days from water contact. For example, the hydraulic powder obtained by the production method of the present invention Even when blending and replacing hydraulic powders (blast furnace slag, fly ash, limestone, etc.) with low initial age strength after contact with water, compared to the case of using hydraulic powders not yet implemented in the present invention It has advantages such as being able to obtain the strength of 24 hours and 7 days, which is equivalent or better.

(Example 1-1)
Component, CaO: about 68%, SiO _2: about 25%, Al ₂ O _3: about 4%, Fe ₂ O _3: about 3%, MgO other: to be about 3% (by weight), limestone The clay, silica, iron oxide raw materials and the like fired in combination were primarily pulverized by a crusher and grinder, and a normal Portland cement clinker was obtained by passing through a 3.5 mm sieve.

1000 g of this clinker, 30.3 g of dihydrate gypsum having an SO ₃ amount of 45.93 wt% (1.4 parts by weight of SO _{3 with} respect to 100 parts by weight of clinker), and glycerin (purified glycerin manufactured by Kao Corporation) A ball mill (AXB-15, Co., Ltd.) was used as a material to use 3.2 g of a 50% aqueous solution (solid content 1.6 g) and 8.0 g of sodium sulfate (manufactured by Wako Pure Chemical Industries, Ltd., reagent). ), Manufactured by Seiwa Giken Co., Ltd.) and pulverized by a ball mill. For grinding with a ball mill, stainless steel pots with a capacity of 18 liters (outer diameter 300 mm), 30 pieces of 30 mmφ (nominal 1/4) and 70 20 mmφ (nominal 3/4) 70 (total of 100) stainless balls are used. The ball mill was rotated at 35 rpm.

The target brane value is set to 3300 ± 100 cm ² / g, and after 60 minutes, 75 minutes, and 90 minutes from the start of grinding, a part of the ground product is discharged and sampled, and the brain value of the sample is measured to obtain the target brain value of 3300 cm ² / g. The reaching time was determined by a quadratic regression equation of Microsoft Excel 2003 manufactured by Microsoft Corporation. The time was the final arrival time (crush arrival time), and the pulverization was finished to obtain cement. The final arrival time was 108 minutes. The final arrival time when glycerin and sodium sulfate were not added was 120 minutes. Moreover, the measurement of a brane value used the brane air permeation | transmission apparatus prescribed | regulated to the physical test method (JISR5201) of a cement.

  Next, mortar was prepared from the obtained cement according to Cement Physical Test Method (JIS R 5201), Annex 2 (Cement Test Method—Measurement of Strength), and the strength was measured for 24 hours and 7 days. From the viewpoint of manufacturing concrete products and structures, it is desirable that the 24-hour strength and the 7-day strength are larger.

(Comparative Example 1-1)
A cement was obtained in the same manner as in Example 1-1 except that sodium sulfate was not added as a material used for grinding. The final arrival time was 108 minutes. To the obtained cement, 8.0 g of sodium sulfate (0.80 parts by weight with respect to 100 parts by weight of clinker) was added and mixed to prepare a mortar in the same manner as in Example 1-1. It was measured.

(Comparative Example 1-2)
A cement was obtained in the same manner as in Example 1-1 except that glycerin was not added as a material used for grinding. The final arrival time was 120 minutes. A mortar was prepared in the same manner as in Example 1-1 by adding and mixing 3.2 g of a 50% aqueous solution of glycerin (solid content: 1.6 g) (0.16 parts by weight with respect to 100 parts by weight of clinker) to the obtained cement. Then, the strength for 24 hours and the strength for 7 days were measured.

  The results of Example 1-1, Comparative Example 1-1, and Comparative Example 1-2 are shown in Table 1.

(Example 2-1 and Comparative Example 2-1)
Mortar was prepared in the same manner as in Example 1-1 and Comparative Example 1-1 except that monoacetin (glycerin monoacetate ester, manufactured by Wako Pure Chemical Industries, Ltd., reagent) was used instead of glycerin. Time intensity and 7-day intensity were measured. The results are shown in Table 2. Note that the final arrival times of Example 2-1 and Comparative Example 2-1 were both 100 minutes.

(Example 3-1 and Comparative example 3-1)
Mortar was prepared in the same manner as in Example 1-1 and Comparative Example 1-1 except that the amount of sodium sulfate added was 16 g, and the strength for 24 hours and the strength for 7 days were measured. The results are shown in Table 3. The final arrival times of Example 3-1 and Comparative Example 3-1 were 109 minutes and 108 minutes, respectively.

(Example 4-1 and Comparative example 4-1)
Mortar was prepared in the same manner as in Example 1-1 and Comparative Example 1-1 except that the amount of glycerin added was 0.4 g and the amount of sodium sulfate added was 2.0 g. The strength was measured. The results are shown in Table 4. The final arrival times of Example 4-1 and Comparative Example 4-1 were 102 minutes and 101 minutes, respectively.

  From Tables 1 to 4, by adding and pulverizing both the one or more compounds (A) selected from glycerin and glycerin monoacetate and the alkali metal sulfate sulfate (B) during pulverization of the hydraulic powder, 24 It can be seen that the time intensity and the 7-day intensity are greatly improved.

Claims (2)

A method for producing a hydraulic powder comprising adding one or more compounds A selected from glycerin and glycerin monoacetate (hereinafter referred to as compound A) and an alkali metal sulfate B to a hydraulic compound and pulverizing them. ,
Compound A is added in an amount of 0.01 to 1.50 parts by weight with respect to 100 parts by weight of the hydraulic compound,
The addition amount of the alkali metal sulfate B is 0.02 to 2.0 parts by weight with respect to 100 parts by weight of the hydraulic compound,
The weight ratio of compound A and alkali metal sulfate salt B [compound A / alkali metal sulfate B] is 0.1 to 2.0.
A method for producing hydraulic powder. The manufacturing method of the hydraulic powder of Claim 1 whose compound A is glycerol monoacetic acid ester.