KR102576649B1 - Low carbon and low energy cement clinker, manufacturing method of the same and manufacturing method of cement using the same - Google Patents

Abstract

The present invention relates to cement clinker, a method of manufacturing the cement clinker, and a method of manufacturing cement using the cement clinker, wherein the cement clinker includes calcium sulfo aluminate (CSA), alite (Ca ₃ SiO ₅ , C ₃ S), belite (2CaO·SiO ₂ , C ₂ S), aluminate (3CaO·Al ₂ O ₃ , C ₃ A), ferrite (4CaO·Al ₂ O ₃ ·Fe ₂ O ₃ , C ₄ AF), calcium oxide (CaO), and calcium sulfate (CaSO ₄ ), including 10 to 40% by weight of CSA, 20 to 40% by weight of C ₃ S, and 10 to 40% by weight of C ₂ S. It is characterized in that it is a CSA-C ₃ SC ₂ S clinker containing.

Description

Low-carbon, low-energy cement clinker, a method of manufacturing the cement clinker, and a method of manufacturing cement using the cement clinker. {LOW CARBON AND LOW ENERGY CEMENT CLINKER, MANUFACTURING METHOD OF THE SAME AND MANUFACTURING METHOD OF CEMENT USING THE SAME}

The present invention relates to cement clinker, a method of manufacturing the cement clinker, and a method of manufacturing cement using the cement clinker. More specifically, the present invention relates to a low calcination temperature and low carbon dioxide emissions compared to general cement clinker, realizing low carbon and low energy. It relates to a cement clinker, a method of manufacturing the cement clinker, and a method of manufacturing cement using the cement clinker.

With the expansion of industrial infrastructure, advancement of industry, and expansion of living space, the characteristics of concrete are diversifying and its uses are expanding. Accordingly, in addition to the general characteristics of existing concrete, enhanced characteristics according to the intended use are required.

Ordinary Portland Cement (OPC) clinker (hereinafter referred to as OPC clinker), which is widely used as a building material, is fired at a high temperature of about 1,450℃, and is subjected to the decarboxylation reaction of limestone, which accounts for the largest amount of OPC raw materials, and bituminous coal. Due to the use of the same fossil raw materials, carbon dioxide (CO ₂ ), the main culprit of greenhouse gases, is emitted up to about 0.8 tons per ton of cement, which is a problem.

For this reason, clinker that can replace the OPC clinker is being developed. A representative example is CSA-based clinker, which mainly contains Calcium Sulfo Aluminate (CSA, C ₄ A ₃ S), which has a firing temperature of around 1,200-1,300℃, which is 100-200 degrees lower than that of OPC clinker. Not only does it save energy because the temperature is low, but it also has the advantage of reducing CO ₂ emissions as the amount of limestone input is reduced. In addition, CSA cement has a faster setting time and strength development speed than other general cements, so it can be used in emergency construction, shotcrete, and secondary products, such as called ultra-fast hardening cement, and can complement the shortcomings of existing OPC clinker.

However, despite these advantages, there is a problem in that there is no bauxite resource, a source of alumina, in Korea, so all CSA cement is imported and used from overseas.

The crystal structure of CSA (C ₄ A ₃ S) clinker, which constitutes the CSA-based cement, is a porous crystal framework composed of Al-O tetrahedral groups connected to each node, and a single lattice located within the framework structure ( cell), there are four quadrangular rings connected from four Al-O tetrahedra by nodal points, and these four quadrangles form an axial hole path in the direction parallel to the axis of the 001 plane. Inside the pore structure, other tetrahedra of SO are located in 1/4 coordination and 3/4 coordination, respectively, and all square rings are combined with Al-O tetrahedra to form eight hexagonal axial directions parallel to the axis of the 001 plane. A pore structure is formed, and Ca ²⁺ ions are located at 0 coordination and 1/2 coordination in the axial pore structure.

Therefore, in order to improve the properties of the CSA clinker in consideration of the crystal structure, a certain amount of belite (2CaO·SiO ₂ , C ₂ S) is formed. By mixing this belite, the compressive strength of concrete is improved and durability is improved. It is effective (Korean Patent Publication No. 10-1879727).

In addition, in Korean Patent Publication No. 10-1999-0049245 and Korean Patent Publication No. 10-2137711, the high fluidity and low heat characteristics of concrete are improved by including belite and alite (Ca ₃ SiO ₅ , C ₃ S) in clinker. Improved features such as:

The results of this prior art suggest that the properties of clinker can be improved by containing a certain amount of a separate crystal structure such as belite or alite in CSA clinker.

Republic of Korea Patent Publication No. 10-1879727 Republic of Korea Patent Publication No. 10-1999-0049245

The present invention was developed in consideration of the above-described prior art, and provides cement clinker and its production that can lower the firing temperature during the manufacturing process and reduce CO ₂ emissions by ensuring that the cement clinker contains a certain amount of belite and alite. The purpose is to provide a method.

In particular, the aim is to manufacture CSA-based cement clinker using industrial by-products as raw materials, and to provide a cement clinker and a method for manufacturing the same that can improve physical properties such as compressive strength and curing speed of concrete through the obtained CSA-based cement clinker. The purpose.

The cement clinker of the present invention to solve the above problems includes Calcium Sulfo Aluminate (Ca ₄ (AlO ₂ ) ₆ SO ₄ , CSA), alite (Ca ₃ SiO ₅ , C ₃ S), and Bell. Belite (2CaO·SiO ₂ , C ₂ S), aluminate (3CaO·Al ₂ O ₃ , C ₃ A), ferrite (4CaO·Al ₂ O ₃ ·Fe ₂ O ₃ , C ₄ AF) , calcium oxide (CaO), calcium sulfate (CaSO ₄ ), and comprising 10 to 40% by weight of CSA, 20 to 40% by weight of C ₃ S, and 10 to 40% by weight of C ₂ S. do.

At this time, the cement clinker may be obtained from limestone, coal ash, slag, and gypsum.

In addition, the method for producing cement clinker according to the present invention includes the steps of grinding and mixing limestone, coal ash, slag, and gypsum to produce a mixture, calcining the mixture at a temperature of 1,200 to 1,300° C. to produce cement clinker, Characterized in that it includes the step of cooling the cement clinker.

At this time, the slag preferably contains 0.3 to 1.0% by weight of fluorine.

In addition, the mixture preferably consists of 35 to 50% by weight of limestone, 10 to 20% by weight of coal ash, 30 to 40% by weight of slag, and 5 to 10% by weight of gypsum.

In addition, the method of manufacturing cement using the cement clinker involves grinding 80 to 100 parts by weight of the cement clinker to a fineness (brain specific surface area) of 3,000 to 8,000 cm2/g, and then grinding the cement clinker to a fineness of 3,000 to 8,000 cm2/g. It is preferable to prepare it by adding 0 to 20 parts by weight, or to mix 80 to 100 parts by weight of the cement clinker and 0 to 20 parts by weight of gypsum and then grind them together to have a powder degree of 3,000 to 8,000 cm2/g.

The cement clinker according to the present invention contains belite and alite in a certain amount, thereby lowering the firing temperature during the manufacturing process and reducing CO ₂ emissions.

In addition, while manufacturing CSA-based cement clinker using industrial by-products as raw materials, the obtained CSA-based cement clinker has the effect of improving the physical properties such as compressive strength and curing speed of concrete.

Figure 1 is a process diagram showing a method of manufacturing cement using the cement clinker of the present invention.
Figure 2 shows the results of X-ray diffraction analysis for CSA-C ₃ SC ₂ S clinker samples 1 to 3.
Figure 3 shows the results of X-ray diffraction analysis for CSA-C ₃ SC ₂ S clinker samples 4 and 5.
Figure 4 shows the results of X-ray diffraction analysis for CSA-C ₃ SC ₂ S clinker samples 6 to 9.
Figure 5 shows the results of X-ray diffraction analysis for CSA-C ₃ SC ₂ S clinker samples 10 to 13.
Figure 6 shows the results of X-ray diffraction analysis of samples 1 to 4 synthesized by a pilot process of CSA-C ₃ SC ₂ S clinker.
Figure 7 shows the results of measuring the compressive strength of cement manufactured using CSA-C ₃ SC ₂ S clinker, measuring the compressive strength according to the curing time of (a) specimens 1 to 5 and (b) specimens 6 to 10. It is a result.
Figure 8 shows the results of measuring the setting time of cement manufactured using CSA-C ₃ SC ₂ S clinker, showing the initial setting and final setting times of (a) specimens 1 to 5 and (b) specimens 6 to 10. .

Hereinafter, the present invention will be described in detail.

The cement clinker according to the present invention includes Calcium Sulfo Aluminate (CSA), alite (Ca ₃ SiO ₅ , C ₃ S), belite (2CaO·SiO ₂ , C ₂ S), and aluminate. (3CaO·Al ₂ O ₃ , C ₃ A), ferrite (4CaO·Al ₂ O ₃ ·Fe ₂ O ₃ , C ₄ AF), calcium oxide (CaO), and calcium sulfate (CaSO ₄ ). As such, it is characterized in that it contains 10 to 40% by weight of CSA, 20 to 40% by weight of C ₃ S, and 10 to 40% by weight of C ₂ S. In other words, the cement clinker has the effect of improving the physical properties of concrete by containing a certain amount of C ₃ S and C ₂ S in CSA.

The cement clinker is obtained from limestone, coal ash, slag, and gypsum, and the effects of cost reduction and resource recycling can be achieved by using coal ash and slag, which are industrial by-products. Coal ash, which is a raw material for obtaining the cement clinker, is a by-product generated in a pulverized coal boiler type thermal power plant, and the slag can be used as refining slag generated in a special steel manufacturing process. Additionally, it is preferable to use flue gas desulfurization gypsum as the gypsum.

In general, when manufacturing CSA-based cement clinker, it can be manufactured using limestone, coal ash, bauxite, and gypsum as raw materials. The analysis results of these raw materials using an X-ray fluorescence spectrometer (XRF) are shown in Table 1.

SiO ₂ Al ₂ O _{3 Fe2O3 _} CaO SO ₃ MgO limestone 6.67 0.66 0.28 53.36 0.17 0.47 coal ash 57.80 22.90 10.20 4.02 0.05 1.24 bauxite 4.96 45.90 19.80 0.05 0.13 0.02 gypsum 1.39 0.28 0.20 44.80 51.20 0.09

CSA clinker is manufactured by mixing and firing each raw material. CSA clinker with a CSA content of 50 to 70% by weight is called CSA-only clinker, CSA content is 20 to 30% by weight, and C ₂ S content is 40 to 60% by weight. This is called CSA-C ₂ S clinker. The CSA-only clinker can be used by mixing with OPC when manufacturing concrete, and CSA-C ₂ S clinker has the advantage of being able to be used alone without mixing with OPC.

Therefore, for CSA synthesis, various studies are being conducted to establish a raw material mixing equation according to the properties of the raw materials. Among these, the formula below published by Mehta in 1974 has been most widely used as the relationship formula between the chemical components of raw materials and the product. Using this Mehta relationship, the production rate after the sintering reaction can be predicted from the chemical composition of the raw materials, so it is most commonly used when synthesizing CSA-based cement clinker.

The CSA-based cement clinker includes C ₃ A, C ₄ AF, CaO, CaSO ₄ , etc. in addition to CSA, C ₃ S and C ₂ S, and C ₄ AF is Fe ₂ O ₃ , Al ₂ O ₃ , CaO Since it is a component produced by sintering, the amount of CSA produced is primarily affected by the amount of C ₄ AF produced. Additionally, the remaining Al ₂ O ₃ reacts with CaO to form C ₃ A. In addition, since the C ₃ S and C ₂ S are formed by reacting the silicate component contained in the raw material with unreacted calcium after CSA is generated, the component ratio varies depending on the content of the raw material and firing conditions.

In addition, in order to improve compressive strength by lowering the firing temperature and reducing the amount of limestone used compared to OPC cement manufactured at a high firing temperature of 1,450°C, the present invention applies CSA-C ₃ SC ₂ S clinker to make cement. It is being manufactured.

The cement can be manufactured through the same sequence of processes as in FIG. 1.

First, the raw materials (limestone, coal ash, slag and gypsum) are crushed and the ground powder is mixed to prepare the mixture. The raw materials for producing the mixture are preferably comprised of 35 to 50% by weight of limestone, 10 to 20% by weight of coal ash, 30 to 40% by weight of slag, and 5 to 10% by weight of gypsum. By mixing the raw materials in the above range, cement clinker of the composition desired in the present invention can be obtained.

Next, the mixture is fired at a temperature of 1,200 to 1,300°C to produce cement clinker. Cement clinker is obtained by quenching the produced cement clinker. Next, cement can be obtained through a process of milling the cement clinker.

When manufacturing cement by adding gypsum in the grinding process of the cement clinker to produce low-carbon, low-energy cement in the cement manufacturing process, 80 to 100 parts by weight of the cement clinker is added to have a fineness (brain specific surface area) of 3,000 to 3,000. Cement can be produced by grinding to 8,000 cm2/g and then adding 0 to 20 parts by weight of gypsum with a powder fineness of 3,000 to 8,000 cm2/g. In addition, 80 to 100 parts by weight of the cement clinker and 0 to 20 parts by weight of gypsum may be mixed and then ground together to produce a powder of 3,000 to 8,000 cm2/g.

Existing OPC clinker is fired at 1,450℃, and it is desirable to apply a mineralizer mechanism to lower the firing temperature. For this purpose, CSA-C ₃ SC ₂ S clinker is synthesized at low temperature by containing F (fluorine) and SO ₃ components. For this purpose, limestone, coal ash, slag, and gypsum are used as raw materials, and it is preferable to use the raw materials made of the elements shown in Table 2. In Table 2, the unit is weight%.

SiO ₂ Al ₂ O _{3 Fe2O3 _} CaO SO ₃ MgO limestone 6.67 0.66 0.28 53.36 0.17 0.47 coal ash 57.80 22.90 10.20 4.02 - - slag 11.30 23.40 1.62 56.10 3.06 - gypsum 2.69 1.68 0.80 49.70 44.00 -

When producing clinker using the above raw materials, it was found that clinker containing 10 to 40% by weight of CSA, 20 to 40% by weight of C ₃ S, and 10 to 40% by weight of C ₂ S was obtained.

Samples 1 to 3 were prepared by mixing the raw materials in the content ratio as shown in Table 3 and firing them at 1,250°C (unit: weight %). At this time, coal ash recovered from a pulverized coal boiler type thermal power plant was used, and refining slag generated during the production of special steel was recovered and used as slag.

limestone coal ash slag gypsum sample 1 40 15 30 15 sample 2 43 12 30 15 Sample 3 55 15 15 15

The results of analyzing the manufactured clinker sample using an X-ray diffraction device (XRD) and an X-ray fluorescence analyzer (XRF) are shown in Figure 2. Additionally, from the above analysis results, Samples 1 to 3 were found to consist of the components shown in Table 4.

C ₃ S C ₂ S C ₃ A C _4AF CSAs CaO _CaSO4 Sample 1 11.52 46.28 - 12.12 22.70 0.47 1.01 sample 2 38.38 20.41 - 12.66 21.69 1.11 0.94 Sample 3 1.35 50.40 - 14.10 28.86 - 0.66

As a result of review based on the correlation between the fluorine component contained in slag and the SO ₃ component contained in gypsum, it was confirmed that Sample 2 showed the closest result to the desired CSA-C ₃ SC ₂ S clinker. In addition, since the melting point in the clinkering process can be lowered by the mineralizer, it is expected that C ₃ S can be produced even at a relatively low sintering temperature.

Next, clinker was manufactured using raw materials with elemental contents according to XRF analysis as shown in Table 5. At this time, the raw material slag containing a certain amount of fluorine was used.

SiO ₂ Al ₂ O _{3 Fe2O3 _} CaO SO ₃ MgO F Ig.Loss limestone 5.43 0.68 0.29 55.02 0.12 0.49 - 37.75 coal ash 52.50 21.40 6.63 7.67 0.98 1.94 - 3.8 slag 9.62 27.50 0.67 56.20 2.53 2.31 0.41 - gypsum 0.93 0.47 0.50 46.30 43.30 0.39 - 7.84

To prepare a clinker sample, clinker was synthesized by firing the raw materials as shown in Table 6 (unit: weight %).

limestone coal ash slag gypsum Sample 4 40 15 30 15 Sample 5 43 12 30 15

The XRD analysis results of the synthesized clinker are shown in Figure 3, and from the above analysis results, it was confirmed that clinker with the components shown in Table 8 was synthesized.

C ₃ S C ₂ S C ₃ A C _4AF CSAs CaO _CaSO4 Sample 4 9.53 42.46 0.86 4.78 28.37 0.83 4.29 Sample 5 26.27 24.75 1.37 3.61 26.46 2.75 5.43

The XRD analysis confirmed that CaO and CaSO ₄ existed alone in Sample 5, and from this, the sample was prepared by adjusting the amount of gypsum added as shown in Table 9 (unit: weight %). This lowered the gypsum content from 15% by weight to 10 to 12% by weight, and clinker samples were synthesized by adjusting the contents of limestone and slag according to the gypsum content.

limestone coal ash slag gypsum Sample 6 43 15 30 12 Sample 7 45 15 30 10 Sample 8 43 12 33 12 Sample 9 43 12 35 10

The XRD analysis results for the synthesized clinker of Samples 6 to 9 are shown in Figure 4, and from the analysis results, it was confirmed that clinker with the components shown in Table 9 was synthesized.

C ₃ S C ₂ S C ₃ A C ₄ AF CSAs CaO _CaSO4 Sample 6 20.52 36.14 0.24 5.36 26.93 0.55 2.83 Sample 7 21.97 32.46 0.30 5.50 27.54 0.85 1.90 Sample 8 33.70 17.74 - 4.28 30.86 2.66 2.68 Sample 9 37.45 16.85 - 4.63 31.65 1.77 0.89

From the results in Table 9, it was confirmed that when the gypsum was lowered to 10% by weight, a sample close to the desired content ratio in the present invention could be synthesized with CSA 31.65% by weight, C ₃ S 37.45% by weight, and C ₂ S 16.85% by weight. did.

Based on Sample 9, which was judged to have the most appropriate content ratio in Table 9 above, the amount of limestone input was reduced in order to create a mixture capable of reducing greenhouse gas emissions, and in order to secure economic efficiency, the input amount of gypsum, which has the highest unit cost among the raw materials, was reduced to Table 10 and The raw materials were mixed with the same composition.

limestone coal ash slag gypsum Sample 10 44.0 13.0 35.0 8.0 Sample 11 45.5 14.5 35.0 5.0 Sample 12 43.0 12.0 35.0 10.0 Sample 13 38.0 12.0 40.0 10.0

In addition, the element content of the clinker of Samples 10 to 13 is shown in Table 11.

C ₃ S C ₂ S C ₃ A C ₄ AF CSAs CaO _CaSO4 Sample 10 36.47 19.23 0.60 4.56 30.06 1.47 0.41 Sample 11 23.55 30.17 4.78 6.84 23.36 1.43 0.12 Sample 12 38.87 15.01 - 4.48 31.34 1.82 1.31 Sample 13 33.26 17.19 0.05 5.18 34.82 0.53 0.78

From the XRD measurement results in Table 11 and Figure 5, the experimental results of reducing the amount of limestone and gypsum based on Sample 9 showed that the amount of limestone could be reduced to 38% by weight, and the amount of gypsum could be reduced to 8% by weight, as shown in Table 12. It was confirmed that it was possible. Therefore, it was found that when synthesizing clinker according to the present invention, limestone, which is a raw material, can be contained in the range of 38 to 50% by weight, and gypsum can be contained in the range of 8 to 15% by weight.

In general, cement clinker is R.H., which can estimate cement properties by calculating the composition of the four major cement minerals through chemical composition. Bogue (1929) is widely used, and includes Lime Saturation Factor (LSF), Silica Modulus (SM), and Iron Modulus (IM).

Since the cement clinker is a new clinker that contains calcium sulfo aluminate (C4A3S, CSA) in addition to the four major cement minerals, a new modulus presentation is necessary.

The US patent “Hybrid Cement Clinker and Cement Made from That Clinker, US 8,986,444 B2” presents the modulus including the four major minerals of cement and CSA minerals, as shown in the formula below.

In the above equation, LAD (Lime Adequate Degree) is the lime saturation rate and can be viewed as the amount of limestone required when manufacturing clinker. Additionally, RSA (Ratio of Silicates and Aluminates) refers to the ratio of silicates and aluminates, and RSF (Ratio of Sulfoaluminates and Ferroaluminates) refers to the ratio of CSA to ferroaluminates.

By applying the above modulus, it can be effectively applied to produce low-carbon, low-energy cement clinker, and the application results are shown in Table 12.

division Raw material composition (%) Clinker mineral phase (%) Modulus limestone coal ash slag gypsum C ₃ S C ₂ S C ₄ A ₃ S C _4AF LAD RSA RSF Sample 1 40.0 15.0 30.0 15.0 11.52 46.28 22.70 12.12 0.72 1.66 1.87 Sample 2 43.0 12.0 30.0 15.0 38.38 20.41 21.69 12.66 0.86 1.71 1.71 Sample 3 55.0 15.0 15.0 15.0 1.35 50.40 28.86 14.10 0.67 1.20 2.05 Sample 4 40.0 15.0 30.0 15.0 9.53 42.46 28.37 4.78 0.71 1.57 5.94 Sample 5 43.0 12.0 30.0 15.0 26.27 24.75 26.46 3.61 0.81 1.70 7.33 Sample 6 43.0 15.0 30.0 12.0 20.52 36.14 26.93 5.36 0.77 1.75 5.02 Sample 7 45.0 15.0 30.0 10.0 21.97 32.46 27.54 5.50 0.78 1.65 5.01 Sample 8 43.0 12.0 33.0 12.0 33.70 17.74 30.86 4.28 0.86 1.46 7.21 Sample 9 43.0 12.0 35.0 10.0 37.45 16.85 31.65 4.63 0.88 1.50 6.84 Sample 10 44.0 13.0 35.0 8.0 36.47 19.23 30.06 4.56 0.86 1.61 6.59 Sample 11 45.5 14.5 35.0 5.0 23.55 30.17 23.36 6.84 0.79 1.78 3.42 Sample 12 43.0 12.0 35.0 10.0 38.87 15.01 31.34 4.48 0.89 1.50 7.00 Sample 13 38.0 12.0 40.0 10.0 33.26 17.19 34.82 5.18 0.86 1.26 6.72

From the above experimental results, it was confirmed that the cement clinker that satisfies the physical properties required in the present invention preferably exhibits an LAD of 0.8 to 0.9, an RSA of 1.2 to 1.7, and an RSF of 1.7 to 7.2.

From the above experimental results, clinker was synthesized by firing at 1,250°C for 1 to 2 hours using a cement pilot kiln (about 3 tons/day). Firing was performed by putting the raw materials into a kiln stabilized at 1,250°C. At this time, the mixing ratio of raw materials is shown in Table 13.

limestone coal ash slag gypsum Pilot sample 1 43.0 12.0 35.0 10.0 Pilot sample 2 45.0 10.0 35.0 10.0 Pilot sample 3 49.0 10.0 35.0 6.0 Pilot sample 4 45.0 11.0 35.0 9.0

XRD analysis of the synthesized samples confirmed whether CaO and CaSO ₄ existed alone. The synthesized samples were confirmed to consist of the same ingredients as shown in Table 14.

C ₃ S C ₂ S C ₃ A C _4AF CSAs CaO _CaSO4 Pilot sample 1 10.79 38.88 - 4.50 25.76 3.31 0.99 Pilot sample 2 24.79 27.29 0.70 5.67 23.05 1.88 1.06 Pilot sample 3 24.11 24.80 2.47 7.37 22.76 5.19 0.41 Pilot sample 4 36.84 14.97 0.76 7.09 26.53 2.28 2.23

Among the pilot samples, samples 3 and 4 were found to have a high content of C ₃ A, so concrete was manufactured using the pilot samples 3 and 4 with the ingredients as shown in Table 15 (unit: weight %). In Table 15, Samples 1 to 5 used the clinker of Pilot Sample 3, and Samples 6 to 10 used the clinker of Pilot Sample 4.

OPC clinker gypsum Plain 100 - - Psalm 1 - 100 - Psalm 2 - 95 5 Psalm 3 - 90 10 Psalm 4 - 85 15 Psalm 5 - 80 20 Psalm 6 - 100 - Psalm 7 - 95 5 Psalm 8 - 90 10 Psalm 9 - 85 15 Psalm 10 - 80 20

The results of measuring the compressive strength according to the curing period for the manufactured concrete specimen are shown in Figure 7. Looking at the results in Figure 7, it was shown that when applying the clinker according to the present invention, high compressive strength of cement can be achieved without mixing OPC. In addition, even if 10 to 20% by weight of gypsum was contained during cement manufacturing, the compressive strength due to curing was sufficiently high, showing that price competitiveness in cement manufacturing could be increased.

In addition, looking at the results in Figure 8, it was found that when manufacturing cement using the cement clinker of the present invention, the setting time was shortened, making it possible to shorten the cement curing time and period.

Although the present invention has been described through preferred embodiments as described above, it is not limited to the above embodiments and various modifications and modifications may be made by those skilled in the art without departing from the spirit of the present invention. Change is possible. Such modifications and variations should be considered to fall within the scope of the present invention and the appended claims.

Claims (7)

delete delete delete A method for producing cement clinker, comprising:
Preparing a mixture by grinding and mixing 45 to 49% by weight of limestone, 10 to 11% by weight of coal ash, 35% by weight of slag, and 6 to 9% by weight of gypsum;
Preparing cement clinker by calcining the mixture at a temperature of 1,250°C for 1 to 2 hours;
Cooling the cement clinker;
Includes,
The coal ash is recovered from a pulverized coal boiler-type thermal power plant, the slag is recovered from refining slag generated during the production of special steel, and the gypsum is flue gas desulfurized gypsum.
Manufacture of cement clinker, characterized in that the cement clinker exhibits a Lime Adequate Degree (LAD) of 0.8 to 0.9, a Ratio of Silicates and Aluminates (RSA) of 1.2 to 1.7, and a Ratio of Sulfoaluminates and Ferroaluminates (RSF) of 1.7 to 7.2. method.
delete In claim 4,
A method for producing cement clinker, characterized in that the slag contains 0.3 to 1.0% by weight of fluorine.
A method of manufacturing cement using cement clinker manufactured according to the manufacturing method of claim 4,
It is manufactured by grinding 80 to 100 parts by weight of the cement clinker to a fineness (brain specific surface area) of 3,000 to 8,000 cm2/g and then adding 0 to 20 parts by weight of gypsum with a fineness of 3,000 to 8,000 cm2/g, or the cement clinker. A method for producing cement, characterized in that 80 to 100 parts by weight and 0 to 20 parts by weight of gypsum are mixed and then ground together to produce a powder degree of 3,000 to 8,000 cm2/g.