Cement raw material with high sunlight absorption rate and preparation method and application thereof

Abstract

The present invention relates to the technical field of cement preparation, and in particular to a cement raw material with high sunlight absorptivity, a preparation method and an application thereof. The invention relates to a method of preparing a cement raw material with high sunlight absorptivity, wherein Ca(OH)2 is mixed with original cement raw material, added to a mixed solution of copper nitrate and manganese nitrate to react and generate a precipitate, and the precipitate is evenly distributed on the surface of the original cement raw material. The cement raw material with high sunlight absorptivity can be prepared, and when cement clinker is produced using solar energy, the absorption of sunlight by the cement raw material can be greatly improved, thereby improving calcination efficiency and reducing energy consumption in cement production.

Description

Technical Field

[0001] The present invention relates to the technical field of cement preparation, and in particular to a cement raw material with high sunlight absorption rate, and a preparation method and application thereof. Background Art

[0002] The cement industry's energy structure is primarily coal-fired, accounting for approximately 85%, making it an energy- and resource-intensive industry. Carbon dioxide emissions from the cement industry primarily stem from the clinker production process, accounting for approximately 95% of the industry's total carbon emissions. Carbonate decomposition is the primary source of carbon emissions in cement production, and fuel combustion is the second-largest source. Therefore, selecting an energy source that does not emit carbon dioxide can effectively reduce carbon dioxide emissions in the cement industry. Solar energy is an inexhaustible renewable energy source and one of the most widely used renewable energy sources. Therefore, researchers have proposed using solar energy to provide heat for cement clinker calcination, a concept that has been put into practice.

[0003] In the process of using solar energy to produce cement clinker, sunlight directly shines on the cement clinker. When relevant scholars used SF40 solar furnace to produce Portland cement clinker, the chemical and mineral data of the gray clinker produced were very similar to those of standard cement. However, when producing white cement, the clinker produced was very different from the standard. This is because white cement clinker has a very low absorption rate for sunlight and therefore cannot be produced by direct exposure. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a cement raw meal with high sunlight absorptivity. Specifically, Ca(OH)2 is mixed with original cement raw meal, added to a mixed solution of copper nitrate and manganese nitrate to react and generate a precipitate, and the precipitate is evenly distributed on the surface of the original cement raw meal. Thus, cement raw meal with high sunlight absorptivity is prepared. When cement clinker is produced using solar energy, the absorption of sunlight by the cement raw meal can be greatly improved, thereby improving the calcination efficiency and reducing the energy consumption of cement production.

[0005] Specifically, the method for preparing cement raw material with high sunlight absorptivity of the present invention comprises the following steps:

[0006] 1) Weigh the raw materials according to the ratio,

[0007] 2) Dissolve Mn(NO3)2 and Cu(NO3)2 in water and stir evenly to obtain a mixed solution.

[0008] 3) Add Ca(OH)2 to the original cement raw material and mix evenly, then add it to the mixed liquid to obtain a suspension.

[0009] 4) Stir the suspension at a constant temperature.

[0010] 5) Dry and grind to obtain.

[0011] The present invention mixes Ca(OH)2 with raw cement raw materials, adds the mixture to a mixed solution of copper nitrate and manganese nitrate to react and generate a precipitate, and uniformly distributes the mixture on the surface of the raw cement raw materials. During the cement calcination process, the precipitate gradually forms substances such as binary oxides. Research by the present invention shows that materials with a suitable band gap can absorb sunlight radiation to the greatest extent, which is manifested as high absorption of incident light on a macro scale. The present invention has concluded through a large number of experimental studies that Cu and Mn have an ideal band gap, and the emissivity of the materials doped with oxygen atoms in the infrared region is reduced, which can better absorb sunlight. In addition, in order to better achieve the clinker burning effect, the present invention method generates a precipitate on the surface of the raw cement raw materials. During the cement material calcination process, as the temperature rises, copper-manganese oxides are gradually formed. Compared with the addition of oxides in the same proportion, the synthesis on the surface makes the surface area larger, which can more effectively absorb sunlight, thereby improving the absorption rate of sunlight by the cement raw materials.

[0012] Preferably, the molar ratio of Mn(NO3)2 to Cu(NO3)2 is (1.8-2.2):1, the molar ratio of Ca(OH)2 to Cu(NO3)2 is (2.8-3.2):1, and Mn(NO3)2 accounts for 0.8-4% of the mass of the original cement raw material.

[0013] Preferably, the raw cement ratio in step 3) is: KH = 0.87 ± 0.02, SM = 2.56 ± 0.02, and IM = 1.50 ± 0.02. Studies have shown that, unlike traditional cement clinker firing, solar firing requires adjustment of the raw cement ratio to achieve better firing results.

[0014] Preferably, the liquid-to-solid mass ratio in the suspension in step 3) is (1-1.2):1.

[0015] Preferably, in step 2), the stirring speed is 500-600 rpm and the stirring time is 30-40 min.

[0016] Preferably, in step 4), the constant temperature is 70-80° C., the stirring speed is 900-1000 rpm, and the stirring time is 60-90 min.

[0017] Preferably, in step 5), the drying temperature is 100-110° C., and the powder is ground to a particle size of less than 200 μm.

[0018] The present invention also relates to a cement raw material with high sunlight absorptivity, which is specifically prepared by the above-mentioned preparation method.

[0019] The present invention also relates to cement clinker, which is specifically made by burning the above-mentioned cement raw material in a solar light concentrating device.

[0020] The present invention also relates to cement, specifically, prepared from the above-mentioned cement clinker. More preferably, the cement is prepared by grinding the above-mentioned cement clinker and gypsum. More preferably, the cement is prepared by grinding the above-mentioned cement clinker, gypsum, and a mixed material.

[0021] The present invention also relates to the application of the cement in preparing building materials.

[0022] The present invention has the following technical advantages:

[0023] 1. The present invention synthesizes copper and manganese on the surface of the original cement raw material, and gradually forms copper and manganese oxides and other substances during the calcination process to increase the cement raw material's absorption rate of sunlight, thereby getting rid of dependence on traditional fossil energy and achieving low energy consumption and clean energy.

[0024] 2. The method of adding copper manganese oxide in the present invention is to directly synthesize it on the surface of the original cement raw material. When the addition amount is the same, the absorption rate of sunlight is greatly improved.

[0025] 3. The cement clinker and cement prepared by the present invention have good mechanical properties and meet the requirements of use. DETAILED DESCRIPTION

[0026] In order to characterize the technical effect of the present invention, cement raw meal was prepared, 5% water was added to the raw meal and mixed evenly, and the raw meal was pressed into a cake with a diameter of 50 mm and a height of 5 mm by a pressing method. The raw meal was heated to 800°C, 950°C, 1100°C, 1250°C, and 1400°C respectively using a solar concentrating device, and quenched to room temperature after reaching the set temperature. The absorbance of the raw meal samples at room temperature and the samples after heating and quenching was tested using an ultraviolet-visible-near-infrared spectrophotometer. The test wavelength range was 280-2500nm, the scanning slit length was 2nm, the scanning step length was 5nm, and the sunlight weighted absorption ratio was calculated to complete the raw meal test. The cement raw meal was then fired into clinker using a solar concentrating device. After cooling, 4% gypsum and 10% fly ash were added and ground to less than 75μm to obtain cement. Net slurry specimens were prepared according to national standards and the mechanical properties were tested. During the test, the original cement raw material ratio values ​​were: KH=0.87, SM=2.56, IM=1.50.

[0027] Example 1, cement raw meal, the preparation method comprises the following steps: 1) weighing each raw material according to a proportion, 2) dissolving Mn(NO3)2 and Cu(NO3)2 in water and stirring evenly to obtain a mixed solution, 3) adding Ca(OH)2 to the original cement raw meal and mixing evenly, and then adding it to the mixed solution to obtain a suspension, 4) stirring the suspension under constant temperature conditions, 5) drying and grinding to a particle size of less than 200 μm, to obtain, wherein the molar ratio of Mn(NO3)2 to Cu(NO3)2 is 2:1, the molar ratio of Ca(OH)2 to Cu(NO3)2 is 3.1:1, Mn(NO3)2 accounts for 0.8% of the mass of the original cement raw meal, and the liquid-to-solid mass ratio in the suspension is 1.1:1.

[0028] After testing, the weighted absorption ratio of sunlight of cement raw material at room temperature is 33.59%, the weighted absorption ratio after sunlight treatment at 800℃ is 32.59%, the weighted absorption ratio after sunlight treatment at 950℃ is 29.55%, the weighted absorption ratio after sunlight treatment at 1100℃ is 30.97%, the weighted absorption ratio after sunlight treatment at 1250℃ is 41.31%, and the weighted absorption ratio after sunlight treatment at 1400℃ is 56.76%. The 3d compressive strength of cement slurry specimen is 23.6MPa, the 7d compressive strength is 35.8MPa, and the 28d compressive strength is 49.2MPa.

[0029] Example 2, cement raw meal, the preparation method comprises the following steps: 1) weighing each raw material according to a proportion, 2) dissolving Mn(NO3)2 and Cu(NO3)2 in water and stirring uniformly to obtain a mixed solution, 3) adding Ca(OH)2 to the original cement raw meal and mixing uniformly, and then adding the mixture to obtain a suspension, 4) stirring the suspension under constant temperature conditions, 5) drying and grinding to a particle size of less than 200 μm, to obtain, wherein the molar ratio of Mn(NO3)2 to Cu(NO3)2 is 2.1:1, the molar ratio of Ca(OH)2 to Cu(NO3)2 is 3:1, Mn(NO3)2 accounts for 3.5% of the mass of the original cement raw meal, and the liquid-to-solid mass ratio in the suspension is 1.1:1.

[0030] After testing, the weighted absorption ratio of sunlight of cement raw material at room temperature is 42.12%, the weighted absorption ratio after sunlight treatment at 800℃ is 41.87%, the weighted absorption ratio after sunlight treatment at 950℃ is 32.97%, the weighted absorption ratio after sunlight treatment at 1100℃ is 36.02%, the weighted absorption ratio after sunlight treatment at 1250℃ is 47.05%, and the weighted absorption ratio after sunlight treatment at 1400℃ is 58.31%. The 3d compressive strength of cement slurry specimen is 24.9MPa, the 7d compressive strength is 37.3MPa, and the 28d compressive strength is 50.8MPa.

[0031] Comparative Example 1, cement raw meal, the preparation method includes the following steps: 1) weighing each raw material according to the ratio, 2) dissolving Mn(NO3)2 in water and stirring evenly to obtain a mixed solution, 3) adding Ca(OH)2 to the original cement raw meal and mixing evenly, and then adding it to the mixed solution to obtain a suspension, 4) stirring the suspension under constant temperature conditions, 5) drying and grinding to a particle size of less than 200 μm, to obtain, wherein the molar ratio of Ca(OH)2 to Mn(NO3)2 is 3.1:1, Mn(NO3)2 accounts for 0.8% of the mass of the original cement raw meal, and the liquid-to-solid mass ratio in the suspension is 1.1:1.

[0032] After testing, the weighted absorption ratio of sunlight of cement raw material at room temperature is 27.10%, the weighted absorption ratio after sunlight treatment at 800℃ is 27.87%, the weighted absorption ratio after sunlight treatment at 950℃ is 25.56%, the weighted absorption ratio after sunlight treatment at 1100℃ is 25.21%, the weighted absorption ratio after sunlight treatment at 1250℃ is 35.16%, and the weighted absorption ratio after sunlight treatment at 1400℃ is 50.23%. The 3d compressive strength of cement slurry specimen is 19.8MPa, the 7d compressive strength is 29.7MPa, and the 28d compressive strength is 45.3MPa.

[0033] Comparative Example 2, cement raw meal, the preparation method comprises the following steps: 1) weighing each raw material according to a proportion, 2) dissolving Cu(NO3)2 in water and stirring uniformly to obtain a mixed solution, 3) adding Ca(OH)2 to the original cement raw meal and mixing uniformly, and then adding it to the mixed solution to obtain a suspension, 4) stirring the suspension under constant temperature conditions, 5) drying and grinding to a particle size of less than 200 μm, to obtain, wherein the molar ratio of Ca(OH)2 to Cu(NO3)2 is 3.1:1, Cu(NO3)2 accounts for 0.8% of the mass of the original cement raw meal, and the liquid-to-solid mass ratio in the suspension is 1.1:1.

[0034] After testing, the weighted absorption ratio of sunlight of cement raw material at room temperature is 24.76%, the weighted absorption ratio after sunlight treatment at 800℃ is 25.90%, the weighted absorption ratio after sunlight treatment at 950℃ is 24.62%, the weighted absorption ratio after sunlight treatment at 1100℃ is 25.38%, the weighted absorption ratio after sunlight treatment at 1250℃ is 35.44%, and the weighted absorption ratio after sunlight treatment at 1400℃ is 49.92%. The 3d compressive strength of cement slurry specimen is 19.6MPa, the 7d compressive strength is 29.3MPa, and the 28d compressive strength is 46.1MPa.

[0035] Comparative Example 3, cement raw meal, the preparation method includes the following steps: 1) weighing each raw material according to the ratio, 2) dissolving Mn(NO3)2 and Cu(NO3)2 in water and stirring evenly to obtain a mixed solution, 3) adding NaOH to the original cement raw meal and mixing evenly, and then adding it to the mixed solution to obtain a suspension, 4) stirring the suspension under constant temperature conditions, 5) drying and grinding to a particle size of less than 200μm, so as to obtain, wherein the molar ratio of Mn(NO3)2 and Cu(NO3)2 is 2:1, the molar ratio of NaOH and Cu(NO3)2 is 3.1:1, Mn(NO3)2 accounts for 0.8% of the mass of the original cement raw meal, and the liquid-solid mass ratio in the suspension is 1.1:1.

[0036] After testing, the weighted absorption ratio of sunlight of cement raw material at room temperature is 25.57%, the weighted absorption ratio after sunlight treatment at 800℃ is 24.28%, the weighted absorption ratio after sunlight treatment at 950℃ is 23.96%, the weighted absorption ratio after sunlight treatment at 1100℃ is 24.08%, the weighted absorption ratio after sunlight treatment at 1250℃ is 34.32%, and the weighted absorption ratio after sunlight treatment at 1400℃ is 49.81%. The 3d compressive strength of cement slurry specimen is 18.7MPa, the 7d compressive strength is 28.3MPa, and the 28d compressive strength is 43.8MPa.

[0037] Comparative Example 4, cement raw meal, the preparation method includes the following steps: 1) weighing each raw material according to the ratio, 2) adding Ca(OH)2 to the original cement raw meal, mixing evenly, and grinding to a particle size of less than 200 μm, to obtain, wherein Ca(OH)2 accounts for 0.8% of the mass of the original cement raw meal.

[0038] After testing, the weighted absorption ratio of sunlight of cement raw material at room temperature is 20.69%, the weighted absorption ratio after sunlight treatment at 800℃ is 22.44%, the weighted absorption ratio after sunlight treatment at 950℃ is 21.33%, the weighted absorption ratio after sunlight treatment at 1100℃ is 22.15%, the weighted absorption ratio after sunlight treatment at 1250℃ is 30.21%, and the weighted absorption ratio after sunlight treatment at 1400℃ is 42.65%. The 3d compressive strength of cement slurry specimen is 16.2MPa, the 7d compressive strength is 25.1MPa, and the 28d compressive strength is 36.3MPa.

[0039] Comparative Example 5 is different from Example 1 in that the original cement raw material ratio values ​​are: KH=0.98, SM=2.0, IM=1.36, and the others are the same.

[0040] After testing, the weighted absorption ratio of sunlight of cement raw material at room temperature is 26.49%, the weighted absorption ratio after sunlight treatment at 800℃ is 26.91%, the weighted absorption ratio after sunlight treatment at 950℃ is 25.07%, the weighted absorption ratio after sunlight treatment at 1100℃ is 24.76%, the weighted absorption ratio after sunlight treatment at 1250℃ is 35.22%, and the weighted absorption ratio after sunlight treatment at 1400℃ is 50.34%. The 3d compressive strength of cement slurry specimen is 19.4MPa, the 7d compressive strength is 28.8MPa, and the 28d compressive strength is 43.2MPa.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing cement raw meal with high sunlight absorption rate, characterized in that: The steps include: 1) Weigh the raw materials according to the ratio, 2) Dissolve Mn(NO3)2 and Cu(NO3)2 in water and stir evenly to obtain a mixed solution. 3) Add Ca(OH)2 to the original cement raw material and mix evenly, then add it to the mixed solution to obtain a suspension. The molar ratio of Mn(NO3)2 and Cu(NO3)2 is (1.8-2.2):1, the molar ratio of Ca(OH)2 and Cu(NO3)2 is (2.8-3.2):1, and Mn(NO3)2 accounts for 0.8-4% of the original cement raw material mass. The original cement raw material rate values ​​are: KH=0.87±0.02, SM=2.56±0.02, IM=1.50±0.02, 4) Stir the suspension at a constant temperature. 5) Dry and grind to obtain.

2. The preparation method according to claim 1, characterized in that The liquid-to-solid mass ratio in the suspension in step 3) is (1-1.2):

1.

3. The preparation method according to claim 1, characterized in that In step 2), the stirring speed is 500-600 rpm and the stirring time is 30-40 min.

4. The preparation method according to claim 1, characterized in that In step 4), the constant temperature is 70-80°C.

5. The preparation method according to claim 1, characterized in that In step 5), the drying temperature is 100-110°C and the powder is ground to a particle size of less than 200 μm.

6. A cement raw material with high sunlight absorption rate, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 5.

7. Cement clinker, characterized in that The cement raw material according to claim 6 is fired in a solar concentrating device.

8. Cement, characterized in that Prepared from the cement clinker according to claim 7.