KR101275435B1 - Producing method for superfine blast furnace slag blended cement ground by air jet mill - Google Patents

Abstract

The present invention relates to a method for producing blast furnace slag mixed cement of fine powder, and more specifically, to a process for obtaining blast furnace slag fine powder using an air jet mill including a classifier for blast furnace slag, and the blast furnace slag fine powder. And a common Portland cement (OPC) is characterized in that it comprises a process of mixing at a certain ratio.
According to the present invention, the effect of finely pulverized blast furnace slag can be used as a substitute material for cement, and the effect of exhibiting high strength and excellent hydration characteristics in the blast furnace slag mixed cement can be expected.

Description

Producing method for superfine blast furnace slag blended cement ground by air jet mill}

The present invention relates to a method for producing a fine powder blast furnace slag mixed cement using an air jet mill.

Steel waste is produced in the process of producing steel by consuming a large amount of raw materials or energy, and it is about 65% of the main steel in various and quantitative quantities. About 80% of the solid by-products of the steel waste are slag, and the remaining 20% are emitted in the form of sludge and dust. These by-products contain a large amount of useful components such as iron, calcium oxide, calcium silicate, and most of them are utilized in various fields as resources. In Korea, blast furnace slag (BFS, Blast Furnace Slag) is used as a raw material in general cement about 5-25% and blast furnace slag cement about 30 ~ 60%.

The recycling of blast furnace slag will prevent the depletion of mineral resources such as limestone needed for clinker production, save fuel / power consumed in the manufacture of clinker, and help prevent damage to forest resources due to limestone production. . In addition, it is possible to reduce the environmental and economic burden of landfill by industrial by-products. In the cement industry, increasing the utilization of industrial by-products such as slag in order to reduce environmental loads can have a major effect. By using the blast furnace slag as an industrial by-product, it is possible to reduce the relative amount of clinker required for cement production, and to manufacture high-functional concrete having various uses in addition to a CO ₂ reduction effect. At present, the utilization of blast furnace slag is widely used in the case of blast furnace slag cement, mainly for mass concrete, marine concrete, etc., and slag is also used in Ordinary Portland Cement (OPC). The mixture is used within the range of%.

The blast furnace slag cement is widely used for LNG, power plants, coastal structures, various industrial bases, etc., which require special durability because it has superior seawater resistance, watertightness, chemical resistance, and suppression of alkali aggregate reaction, compared to general cement. However, such blast furnace slag cement has disadvantages such as premature strength reduction, neutralization reaction promotion, low temperature hydration reaction reduction and dry shrinkage increase. Many researches have been made to make up for the shortcomings, and many efforts have been made to overcome these shortcomings through the fine powdering of alkali stimulants and blast furnace chain slags that can stimulate the latent hydraulic slag itself. However, in the case of alkali stimulants, since the unit price is high and the mixing range for expressing reference characteristics is remarkably narrow, it is difficult to realize practical use due to severe variation in physical properties of the product during mass production. In addition, blast furnace slag is pulverized to have a powder degree of about 4,000 ㎠ / g (about 16㎛) using a ball mill, roller mill, tube mill, etc. To produce slag having a powder degree in the range of about 6,000 to 8,000 cm 2 / g.

As a result of the efforts to solve the above problems, it was found that the fine powder blast furnace slag having a small particle size can be produced by using the grinding method by the collision force between particles instead of the conventional physical grinding method. .

Accordingly, an object of the present invention is to provide a method for producing a cemented blast furnace slag mixed cement using a fine powder blast furnace slag pulverized using an air jet mill.

As an example for achieving the above object, the manufacturing method of the fine powder blast furnace slag mixed cement according to the present invention is classified into an air pressure of 5 to 10 bar by using an air jet mill including a classifier for the blast furnace slag. Grinding by adjusting the rotational speed of the wheel to 6,500 to 11,000 rpm to obtain a fine powder blast furnace slag of the average particle size range 2.0 to 5.0 ㎛ or 16,000 to 10,000 cm 2 / g, and the fine powder blast furnace chain slag 30 to 50 wt% Portland cement (OPC) is characterized in that it comprises a process of mixing 50 to 70 wt%.

Hereinafter, each process of the present invention will be described in detail.

First, a process of obtaining fine powder blast furnace slag using an air jet mill.

In the present invention, in order to increase the activity of the blast furnace slag, the pulverization of the blast furnace slag was increased, and the particle size distribution was narrowed so that the d90 value was 6 µm or less. Grinding used an air jet mill in which grinding is performed by the collision force of the particles themselves, rather than the conventional physical grinding type (ball mill, rod mill, tube mill, etc.).

The pulverized blast furnace slag particles are pulverized by the collision between the blast furnace slag particles caused by the injection of high pressure air into the apparatus of the air jet mill into which the blast furnace slag is injected, and the powder degree of the crushed blast furnace slag particles is Fineness of the desired particle size can be obtained by adjusting the powder degree by adjusting the rotation speed.

In order to generate the collision force between particles, high pressure air can be injected into the apparatus into which the blast furnace slag is injected, and a device equipped with a classification wheel is used. At this time, by spraying the air of high pressure of 1 to 10 bar to cause the particles to collide themselves by pulverization, the conditions are different depending on the specific gravity and hardness of the raw material to be crushed, but the pulverization It is possible.

As described above, the grinding principle by the air jet mill does not use a grinding paddle when grinding, unlike an impact grinder, so that there is no degree of contamination that may occur when the paddle is worn. The powder pulverized by the collision force between particles moves in the direction of the classification wheel by the airflow formed inside the pulverizer, and the particles of the desired size are classified by the classification wheel, and the large particles are lowered back to the bottom of the pulverizer to be pulverized. And classification can have the same effect.

In order to obtain fine powder blast furnace slag, it is preferable to use a blast furnace slag to be crushed in the size range of 2 to 5 mm in terms of grinding efficiency. If the particles are too large, it takes a long time for fine powdering. The air pressure to be sprayed into the air jet mill is adjusted to be in the range of 5 to 10 bar, preferably in the range of 6 to 8 bar.

On the other hand, fine powders obtained by the above-mentioned grinding through the classification wheel are classified, wherein the rotation speed of the classification wheel is preferably in the range of 6,500 to 11,000 rpm for classification and grinding of the fine powder.

Under the above conditions, fine powder blast furnace slag in the range of 2.0 to 5.0 μm or 16,000 to 10,000 cm 2 / g can be obtained. Compared to the blast furnace slag obtained by ordinary physical forces in the range of 6 to 15 μm or 8,000 to 4,000 cm 2 / g, the above results are remarkable. In addition, according to the present invention, since the distribution of the particle size is narrowly formed, the d90 value is 6 µm or less.

Next, the process of mixing the blast furnace chain slag fine powder and OPC.

The fine powder blast furnace slag is mixed with ordinary portland cement to produce blast furnace slag mixed cement. At this time, the fine powder blast furnace slag is preferably in the range of 30 to 50 wt% to obtain a cement having the desired properties. If the content of the fine powder blast furnace slag is less than the above range, it is difficult to obtain the intrinsic long-term strength enhancement characteristics of the blast furnace slag, and if the content of the fine powder blast furnace slag is higher than the above range, additional raw materials required for the stimulating effect are needed. And it tends to be difficult to express stable properties of the cured product.

On the other hand, for the purpose of promoting the hydraulic properties of the fine powder blast furnace chain slag may comprise an alkali activator in the range of 5 to 10 wt% relative to the fine powder blast furnace chain slag usage. The alkali activator may be used in the range of 325 to 425 mesh of Busan lime, and when the particle size of Busan lime is within the above range there is an advantage that there is no separate pretreatment process other than sieve. The by-product lime may be used by-product during the acetylene gas manufacturing process.

High-powder powder with improved durability by mixing latent hydraulic materials such as fly ash or silica fume in the range of 2 to 20wt% compared to the high-powder blast furnace slag usage for the purpose of promoting the hydraulic properties and improving durability of the fine blast furnace slag. The blast furnace slag mixed cement can be obtained.

In addition, in order to further reinforce the strength of the high-powder blast furnace crushed slag mixed cement, when the additional fine powder blast furnace slag is used in addition to the aluminate-based cement in the range of 5 to 30 wt%, the ultra fine powder blast furnace slag Mixed cement can be obtained.

According to the present invention described above, it is possible to expect the effect that can be used as an alternative to cement by pulverizing the blast furnace slag.

According to the present invention described above, by producing a mixed cement mixed with high fine powder blast furnace slag, it is possible to expect the effect of exhibiting high strength and excellent hydration characteristics.

Figure 1 shows the particle size characteristics of the blast furnace chain slag fine powder according to Example 1, and the slag powder 8,000 cm 2 / g.
Figure 2 shows the X-ray diffraction analysis results according to the hydration time for each compounding sample of Example 2.
Figure 3 shows the DSC analysis results according to the hydration time for each compounding sample of Example 2.
4 and 5 show the pore structure analysis results for each compounding sample of Example 2.
Figure 6 shows the results of the measurement of the condensation test for each compounding sample of Example 2.
Figure 7 shows the compressive strength test results for each compound sample of Example 2.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples.

Reference Example . Starting material

The test materials used below were blast furnace slag with 4,000 and 8,000 ㎠ / g of powder produced by A company in Korea, ordinary portland cement of H company, and Busan lime as an alkali activator. Table 1 shows the chemical composition for each raw material.

Chemical Composition (unit: wt%) SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO SO ₃ Na ₂ O K ₂ O TiO ₂ P ₂ O ₅ LOI OPC ¹⁾ 19.3 4.40 3.99 65.0 1.23 3.02 0.15 1.28 0.30 0.15 1.10 BFS_raw ²⁾ 31.0 14.6 0.43 44.2 4.45 1.68 0.24 0.61 1.68 N.D. 1.02 BFS4000 ³⁾ 29.6 13.1 0.33 46.7 3.60 4.40 0.25 0.56 0.79 0.01 0.70 BFS8000 ⁴⁾ 28.9 12.8 0.36 46.3 3.53 6.11 0.23 0.53 0.67 0.01 0.56 SBFS ⁵⁾ 30.4 14.9 0.43 44.7 4.41 1.69 0.21 0.62 1.75 99.11 0.89 SCL ⁶⁾ 2.51 1.44 0.20 70.3 0.03 0.32 N.D. N.D. 0.05 N.D. 25.0 1) OPC: Ordinary Portland Cement (Powder 3,300blaine), 2) Crushed blast furnace slag about 2mm in size
3) 4,000 ㎠ / g blast furnace slag, 4) 8,000 ㎠ / g blast furnace slag, 5) high fine powder blast furnace slag
6) Busan lime is less than 325 mesh

Busan slaked lime used as an alkali activator of blast furnace slag is produced as a by-product when manufacturing acetylene gas. As calcium carbide (CaC ₂ ) is used as a raw material, it contains a large amount of unreacted carbide and its particle size distribution is uneven.

Table 2 shows the results of the chemical analysis according to the particle size distribution of Busan lime. As shown in Table 2, by-products having a size of 325 mesh or less were used in consideration of the reactivity as an activator.

Particle Size Ranges
(Mesh) Chemical Composition (unit: wt%) SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO SO ₃ C (Carbon) LOI +35 3.92 1.32 7.47 48.9 0.04 0.7 12.19 24.81 -35 to +80 1.57 0.61 3.13 65.1 0.01 0.33 4.09 24.91 -80 ~ + 120 0.83 0.41 0.51 70.9 0.01 0.23 1.81 25.19 -120 ~ + 170 0.63 0.33 0.3 69.4 0.01 0.25 1.46 27.54 -170-+325 1.08 0.62 0.22 71.7 0.02 0.29 1.43 24.57 -325 2.51 1.44 0.2 70.3 0.04 0.44 1.56 23.44

Example  One. Blast furnace slag Fine powder  Produce

Grinding was performed using a GCS-16 model air jet mill from NETZSCH, Germany. The initial particle size of the blast furnace slag was used to about 2 to 3mm, it was ground by adjusting the air pressure of 6 to 8bar, the rotational speed of the classification wheel to 6,500 to 11,000rpm.

Figure 1 shows the slag particle size characteristics after performing the grinding under the above conditions. In addition, the powder currently produced in Korea also shows the particle size of the slag is 8,000 cm 2 / g. As shown in FIG. 1 (a), the particle size of the crushed slag was 2.31 μm based on the Mode value, which was about six times smaller than the 13.61 μm of the BFS8,000. Comparing the d90 value of Figure 1 (b) it can be seen that evenly distributed particles of the same size in the particle size distribution range of 4.61 ㎛ in the fine powder blast furnace slag, 28.42 ㎛ in the BFS8,000.

Example  2. Blast furnace slag  With mixed cement Cured  Manufacture and Characterization

Hydration and physical properties of blast furnace slag fine powder obtained in Example 1 and by using Busan lime as an activator were investigated.

Tables 3 and 4 show the conditions for the experiment. 30 wt% and 50 wt% of slag (BFS4,000, BFS8,000, SBFS) by particle size was added to the OPC, and by-product slag (10 wt%) was added to the added slag content. The paste for hydration characteristics and the water-cement ratio for condensation measurement were 0.4, and the mortar compressive strength test was carried out by setting the water ratio and fine aggregate addition rate according to KS L 5105. For the analysis of paste hydration characteristics, the mixture was hydrated in a thermo-hygrostat with a relative humidity of 98% and a temperature of 23 ± 2 ° C after stirring for 3 minutes with water. The hydration time was set to 1, 3, 7, and 28 days. The hydration was stopped with acetone and dried for 24 hours in a dryer (45 ° C.), followed by test analysis.

Hydration characteristics analysis is XRD (D / MAX 2500V / PC, Rigaku Co. Ltd., Japan), DSC (STA 449C Jupiter, NETZSCH Co. Ltd., Germany), FE-SEM (S-4300, Hitachi Co. Ltd. , Japan), Porosimeter (Auto Pore IV 9520, Micromertics Co. Ltd, USA), and condensation characteristics analysis (KS L 5108).

In the case of compressive strength test, cement: standard yarn = 1: 2.45 according to KS standard. The mold was molded in a 5 × 5 × 5 cm 3 cubic mold and cured for 1 day, followed by curing for 7, 28, and 91 days in moisture to measure the compressive strength according to age.

Type of specimen BFS contents in OPC (wt%) Activator contents in slag (wt%) Curing time (days)
(Curing method) Test
methods Paste, W / S ¹⁾ : 0.4 30, 50 10 1, 3, 7, 28
(humidity chamber) X-ray diffraction
Thermal analysis
Porosimeter
Mortar (W / S: 0.485)
Solid: Send = 1: 2.45 30, 50 7, 28, 91
(water bath) Setting time
Compressive strength 1) water / solid ratio

Mixes designation Mass percent (%) OPC BFS4000 BFS8000 SBFS S1 100 S2 70 30 S3 70 30 S4 70 30 S5 50 50 S6 50 50 S7 50 50

Figure 2 shows the X-ray diffraction analysis results according to the hydration time for each compounding sample of Example 2. The analysis was performed at 2θ: 5 ° to 65 ° and scan speed at 4 ° / min. On the first day of hydration, calcium hydroxide (portlandite, Ca (OH) ₂ ), calcium silicate hydrates (CSH), and ettringite (AFt, Ettringite, C6AH32) were produced as the main hydrates. It can be seen that phosphorus C3S and β-C2S remain (FIG. 2 (a)). It can be seen that the peaks due to ettringite hydrates near 9 °, 16 ° and 19 ° are produced more with slag than with OPC. The reason for this is found in the chemical analysis of the slag used in this study. BFS8,000 contains about 6wt% of SO ₃ , so the gypsum is coated on BFS4,000 and high-powder blast furnace slag for the same experimental conditions. Because of the additional formulation, relatively more gypsum was added than OPC. Therefore, it can be said that the SO ₃ component capable of producing ettringite is increased to produce more ettringite hydration products.

Generally, about 5wt% gypsum (CaSO ₄ ) is added to the slag fine powder for concrete activation. When slag is pulverized, the gypsum is added together and pulverized. In the production of slag powder with high powder density, the finely ground gypsum is pulverized into finer powder and contains more powder than slag. . The peak due to the CSH phase, the main hydration product of the slag cement, overlapped with the peak due to the unreacted cement mineral component, making it difficult to analyze clearly. As hydration proceeds, hydration of C3S, which has a relatively high hydration speed, proceeds rapidly. However, the hydration of C2S proceeds quite slowly, and it can be seen that it remains until the 28th day of hydration.

As shown in (b) of FIG. 2, the ettringite hydrate produced in the early stage of hydration is converted into monosulfate (AFm, Monosulfate, 3C4AH12) hydrate to be produced. The monosulfate generation process in general Portland cement can be expressed as follows.

C3A + 3CH2 + 26H ₂ O → C6AH32

2C3A + C6AH32 + 4H ₂ O → 3C4AH12

C3A + CH + 12H ₂ O → C4AH13

Ettlingite hydrate is produced at maximum on day 1 of hydration and appears around the C3A particles. As the hydration proceeds further, the remaining C3A and ettringite react again to produce monosulfate. Unreacted C3A again produces C-A-H hydrate. In slag cement, monosulfate is produced with different tendency. Substantially, the amount of C3A contained in the OPC will be reduced by the amount of blast furnace slag substituted for the general OPC. Therefore, when interpreting the monosulfate production process as in the case of general OPC, the amount of production should be relatively lower than that of OPC.

However, the slag cement contributes to the formation of ettringite and monosulfate by the elution of the CaO component and Al ₂ O ₃ component of the slag itself, as well as the cement mineral phase C3A. Therefore, it is thought that a higher amount of high sulfate-based hydration product is produced than OPC despite containing a small amount of C3A.

As shown in Figure 2 it can be seen that in the slag-containing specimens than in the case of OPC all the amount of ettringite is converted to monosulfate. The peaks due to unreacted C3S and C2S were reduced significantly, indicating that they were converted to significant hydration products. It can be seen that the peaks of the C-S-H hydration products near 29 ° and 50 ° increase gradually. Comparing the peaks of the main hydration products of slag cement, 29 °, 31 °, and 50 ° CSH phase on the 28th day of hydration of FIG. It can be seen that the peak size is further increased. The peaks caused by monosulfate hydration products are rather smaller when using the fine powder blast furnace slag. It is thought to appear. The strength of hardened cement is largely dependent on the degree of C-S-H hydrate formation (Richardson, 2000; Richardson and Groves, 1992; Chandra and Xu, 1992). Therefore, it can be expected that the compressive strength will be further increased when using the fine powder blast furnace slag.

Figure 3 shows the DSC analysis results according to the hydration time for each sample. DSC analysis was performed at a temperature increase rate of 5 ° C / min from 25 ° C to 700 ° C. As shown in Fig. 3 (a) of hydration 1, the endothermic peak was exhibited by thermal decomposition of CSH hydrate and ettringite hydrate near 120 ° C, and the endothermic peak by decomposition of Ca (OH) ₂ hydrate near 490 ° C. You can check. It was confirmed that a large amount of ettringite was produced in the case of the slag added relatively. As in XRD analysis, hydring time is converted to monosulfate and the amount of CSH hydration product is increased. As shown in (b) of FIG. 3, it can be seen that the endothermic peak due to decomposition of the monosulfate aqueous phase from about 3 days of hydration appears in the vicinity of 200 ° C. In addition, the endothermic peak due to decomposition of the CSH phase in the vicinity of 100 ℃ can be seen that gradually increases with the hydration time. Compared to the endothermic peak due to 500 ℃ Ca (OH) decomposition of a _second product in the vicinity of, the slag replacement ratio is increased as OPC content is reduced to decrease the amount of Ca (OH) ₂ hydrate is produced by the hydration of the C3S and C2S It can be seen that the peak is also small. Also it would be generated when the OPC Ca (OH) ₂ hydrate more and more as the elapsed time of the sign language accordingly peak will also increase. However, in the case of the slag-mixed sample, Ca (OH) ₂ and the added by-lime of cousine were consumed for slag activation, so that the endothermic peak size due to thermal decomposition of Ca (OH) ₂ was also reduced with age. Can be.

4 and 5 and Table 5 shows the pore structure analysis results. Porosity and pore distribution were measured by curing each specimen made with a water-cement ratio of 0.4 for 28 days in moisture (23 ± 2 ℃, 95% relative humidity) and stopping hydration with acetone.

Looking at the cumulative distribution of the pore size of Figure 4 it can be seen that even in the case of a sample with high fine powder added blast furnace slag, the pore distribution appears quite small. In the case of S1 (OPC) it can be seen that relatively large pores of 0.05 to 0.1 ㎛ size distribution, the porosity was also high as 21.3%. In the case of using BFS4,000 of S2, the pore distribution is lowered a little, so that the pore size is reduced to 0.02㎛. The smaller the slag powder, the smaller the pore distribution and size. When BFS8,000 was added, it showed pore size up to 0.01㎛ size, and it was confirmed that the pore distribution slag has a very small pore distribution up to 0.005㎛ size. Comparing the case of adding 30wt% and 50wt% of slag compared to OPC, it was found that the pore size and distribution gradually decreased. When 50 wt% of the fine powder blast furnace slag was added, most of the pores were found to have a size around 10 nm. As the content of blast furnace slag increases, the Al / Ca and Si / Ca ratios increase, thereby decreasing calcium hydroxide hydrate and AFm hydrate while increasing C-S-H hydrate. Indeed, the strength of cement specimens mainly depended on the C-S-H hydration products, and thus the results of this study showed similar results.

Figure 5 shows the distribution of the actual pores. In the case of S1, pore distribution of 0.1 to 0.05 mu m is shown. S2, S3, and S4 to which 30 wt% of slag was added show pore distribution of 0.1-0.01 micrometer, 1-0.05 micrometer, and 0.5-0.05 micrometer, respectively. The total pore distribution was found to be wider than in the case of OPC. However, when the fine powder blast furnace slag is added, it can be seen that there are relatively many pores of less than 10 nm.

As can be seen from the average pore size of Table 5, it had a pore size of 12.5 nm, which is about four times smaller than that of OPC. However, the porosity did not change significantly, so the total porosity was similar but the size was considerably small. When the slag was added 50wt%, the pore distribution had a smaller pore distribution than when 30wt% was added, and the pore distribution of 0.1 to 0.001㎛ was shown when the high fine blast furnace slag was added. The average pore size was 10.5 nm, which was 6 times smaller than OPC.

The above results can be considered as the following factors. Firstly, in the uncured OPC paste, the space between the cement particles is filled by water and air. When the fine powder slag is added as a mixture, the fine powder serves to fill voids in the paste and replace water occupying space. Secondly, slag not only has the effect of densifying the hardened body by producing CSH hydrate, but also has a filling effect of filling the pores of the slag particles. Therefore, the smaller the particle size of the slag, the greater the filling effect of the particles. These results are similar to those of Stovall et al (1986).

Specimens Data summary Median pore diameter
(Volume) Median pore diameter
(Area) Average Pore Diameter Bulk Density at 0.51psia Apparent Density Porosity S1 64.5 nm 44.8 nm 62.1 nm 1.55 g / mL 1.97 g / mL 21.3% S2 27.7 nm 18.3 nm 27.0 nm 1.53 g / mL 1.88 g / mL 18.5% S3 15.1 nm 7.9 nm 13.8 nm 1.51 g / mL 1.85 g / mL 18.5% S4 13.9 nm 6.3 nm 12.5 nm 1.52 g / mL 1.87 g / mL 19.1% S5 24.1 nm 12.9 nm 20.5 nm 1.48 g / mL 1.83 g / mL 18.9% S6 15.0 nm 8.8nm 15.4 nm 1.45 g / mL 1.82 g / mL 20.0% S7 12.0nm 5.7 nm 10.5nm 1.48 g / mL 1.85 g / mL 20.1%

Figure 6 shows the results of the condensation test measurement. The addition of 30 wt% slag showed similar or faster condensation than OPC. In the case of S4 using the fine powder blast furnace slag, the solidification time was 5 hours 15 minutes and 6 hours 55 minutes, respectively. When 50 wt% of slag was added, S5 using BFS4,000 and S6 using BFS8,000 showed slower condensation than OPC. Although it shows lower condensation than S4, it is considered that the addition of 50 wt% of fine powder blast furnace slag shows a faster condensation than the OPC, which has a good effect on the initial strength improvement. This tendency also increases the specific surface area of the slag involved in the reaction as the powder density of the slag increases. Accordingly, due to the activator and Ca (OH) ₂ hydrate from the OPC hydration is considered that a rapid hydration rate from the start.

Figure 7 shows the compressive strength test results for the specimen prepared according to the mixing ratio. As shown in FIG. 7, when the fine powder blast furnace slag was used from the 7th day of hydration, the high compressive strength value was shown. The addition of 50wt% slag showed the highest 640.1kgf / ㎠ and the strength improvement over 200kgf / ㎠ over OPC and about 100kgf / ㎠ over BFS8,000.

Initial (hour: min.) Final (hour: min.) S1 6:05 7:46 S2 5:55 7:40 S3 6:09 7:51 S4 5:15 6:55 S5 7:17 9:16 S6 6:20 8:10 S7 5:47 7:21

Curing
Time Compressive Strength (kgf / ㎠) S1 S2 S3 S4 S5 S6 S7 7days 321.5 309.8 386.0 461.7 305.7 441.7 562.8 28days 389.5 364.2 458.8 549.1 449.7 531.9 638.7 91days 434.7 456.8 484.9 551.4 525.5 533.2 640.1

As described above, when pulverized slag fine powder prepared by using an air jet mill was added to Busanwt lime as an activator and replaced to 50wt% of Portland cement, the following hydration and physical properties were shown.

That is, when the air pressure is adjusted to 6 to 8 bar and the speed of rotation of the classifier wheel to 10,000 rpm using an air jet mill including a classifier, blast furnace slag fine powder having an average particle size of 2.7 μm (16,000 cm 2 / g) is obtained. Can be.

As a result of X-ray diffraction analysis, the main hydration products were Ca (OH) ₂ , CSH, AFt (ettlingite) and AFm (monosulfate). The specimens mixed with the fine powder blast furnace slag showed rapid CSH hydrate production at 28 days of hydration. DSC analysis showed that increasing the addition of bitter powder slag more could be confirmed that the thermal decomposition endothermic peak significantly reduced due to the Ca (OH) ₂ hydrate by the formation of the CSH.

In addition, as a result of measuring the pore size and distribution at 28 days of each sample, when 50wt% of crushed blast furnace slag was added, the average pore size was 10.7 nm, which was about 6 times smaller than that of portland cement. Almost 90% of the distribution was found to be distributed below 10nm. Compressive strength test results showed that 551.4kgf / cm2 when 30wt% was added and 640kgf / cm2 when 50wt% was added when high-powder blast furnace slag was added at 91 days of age. When slag 50wt% was added, the strength value was about 50% for OPC and about 20% higher than BFS8,000.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and various substitutions, modifications, and changes are possible within the scope without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

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Claims (7)

The blast furnace slag was ground to an air pressure of 5 to 10 bar using an air jet mill containing a classifier, and the grinding wheel was adjusted to 6,500 to 11,000 rpm to adjust the rotational speed of the classifier wheel to have an average particle size of 2.0 to 5.0 μm. The process of obtaining slag,
Mixing the fine powder blast furnace slag with 30 to 50 wt% and usually 50 to 70 wt% of portland cement (OPC),
A process of further mixing an alkali activator of 5 to 10wt.% Relative to the fine powder blast furnace chain slag content in the mixture of the fine powder blast furnace chain slag and ordinary Falkland cement
Method for producing a high-fine powder blast furnace slag mixed cement comprising a.
The method according to claim 1,
The blast furnace chain slag is a fine powder blast furnace chain slag mixing cement, characterized in that the particle size is 2 to 5 mm when injected into the air jet mill.
delete The method according to claim 1,
The alkali activator is a method for producing a high fine powder blast furnace chain slag mixed cement, characterized in that by-calcium lime in the range of 325 mesh or more.
The method of claim 4,
The method of producing a fine powder blast furnace slag mixed cement, characterized in that the by-product lime is by-produced during the acetylene gas manufacturing process.
The method according to claim 1,
The high powder blast furnace chain slag mixing cement is a method for producing a high powder blast furnace chain slag mixed cement, characterized in that it further comprises a thermal power plant fly ash or silica fume in the range of 2 to 20 wt% relative to the amount of fine powder blast furnace chain slag used.
The method according to claim 1,
The method of producing a fine powder blast furnace chain slag mixed cement further comprises an aluminate-based cement in the range of 5 to 30 wt% relative to the amount of fine powder blast furnace chain slag used.

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