BELITE-YE'ELIMITE-TERNESITE CEMENT CLINKER AND METHOD FOR PREPARING THE SAME

Abstract

A belite-ye'elimite-ternesite cement clinker includes: ye'elimite: 20-50 wt. %; ternesite: 24-50 wt. %; belite: 10-35 wt. %; and free-calcium sulfate (f-C$): 2-10 wt. %. The composition of cement clinker includes an appropriate amount of ye'elimite minerals, ensuring fast early hydration and high early strength of the cement clinker. The cement clinker further includes a certain amount of free-calcium sulfate (f-C$), and is characterized by its good grindability, leading to decreased energy and mechanical losses essential for clinker grinding. This environmentally conscious and energy-efficient method aligns with the global objective of reducing carbon emissions.

Claims

1. A belite-ye'elimite-ternesite cement clinker, comprising: ye'elimite: 20-50 wt. %; ternesite: 24-50 wt. %; belite: 10-35 wt. %; and free-calcium sulfate (f-C$): 2-10 wt. %.

2. The cement clinker of claim 1, comprising: ye'elimite: 40-43 wt. %; ternesite: 24-35 wt. %; belite: 15-25 wt. %; and free-calcium sulfate (f-C$): 3-5 wt. %; wherein, cubic ye'elimite accounts for 9-15 wt. % of the cement clinker; ?-C.sub.2S accounts for 1-3 wt. % of the cement clinker; and a mass ratio of belite to ternesite is 0.25-1, and a mass ratio of ternesite to ye'elimite is 0.5-1.

3. The cement clinker of claim 2, wherein raw materials of the cement clinker comprise 40-65 wt. % of limestone, 15-30 wt. % of phosphogypsum, 5-20 wt. % of fly ash, and 5-25 wt. % of aluminum source; particularly, raw materials of the cement clinker comprise 48-52 wt. % of limestone, 18-24 wt. % of phosphogypsum, 9-15 wt. % of fly ash, and 18-21 wt. % of aluminum source.

4. The cement clinker of claim 3, wherein the aluminum source is an industrial waste comprising more than 40 wt. % aluminum; and the industrial waste comprises low-grade bauxite, alumina ash, high-alumina fly ash, or a combination thereof, or the limestone comprises 50-60 wt. % CaO; or the phosphogypsum comprises 40-50 wt. % SO.sub.3; or the fly ash comprises 40-60 wt. % SiO.sub.2 and 30-35 wt. % Al.sub.2O.sub.3.

5. The cement clinker of claim 4, wherein the raw materials of the cement clinker comprise the following main chemical compositions: limestone comprising 0.61 wt. % of SiO.sub.2, 0.05 wt. % of Al.sub.2O.sub.3, 0.19 wt. % of Fe.sub.2O.sub.3, 55.9 wt. % of CaO, 0.01 wt. % of MgO, and 0.42 wt. % of SO.sub.3, with a loss on ignition of 42.64; phosphogypsum comprising 1.44 wt. % of SiO.sub.2, 1.19 wt. % of Al.sub.2O.sub.3, 0.62 wt. % of Fe.sub.2O.sub.3, 33.93 wt. % of CaO, 0.31 wt. % of MgO, and 47.04 wt. % of SO.sub.3, with a loss on ignition of 15.45; fly ash comprising 52.47 wt. % of SiO.sub.2, 34.02 wt. % of Al.sub.2O.sub.3, 2.92 wt. % of Fe.sub.2O.sub.3, 4.80 wt. % of CaO, 0.69 wt. % of MgO, and 0.27 wt. % of SO.sub.3, with a loss on ignition of 2.32; low grade bauxite comprising 21.72 wt. % of SiO.sub.2, 52.40 wt. % of Al.sub.2O.sub.3, and 7.63 wt. % of Fe.sub.2O.sub.3, with a loss on ignition of 16.00; alumina ash comprising 27.20 wt. % of SiO.sub.2, 56.16 wt. % of Al.sub.2O.sub.3, 12.49 wt. % of Fe.sub.2O.sub.3, 5.62 wt. % of CaO, 2.80 wt. % of MgO, and 0.78 wt. % of SO.sub.3, with a loss on ignition of ?6.01; and high-alumina fly ash comprising 40.24 wt. % of SiO.sub.2, 48.30 wt. % of Al.sub.2O.sub.3, 2.70 wt. % of Fe.sub.2O.sub.3, 3.17 wt. % of CaO, 0.03 wt. % of MgO, and 0.64 wt. % of SO.sub.3, with a loss on ignition of 2.16.

6. A method for preparing the cement clinker of claim 1, the method comprising: (1) individually grinding the raw materials of the cement clinker; weighting the ground raw materials according to mass percentages; thoroughly mixing the ground raw materials to obtain a raw mixture; pressing the raw mixture into a cake and then drying the cake to obtain a raw clinker cake; and (2) calcining the raw clinker cake; cooling the calcined raw clinker cake to room temperature; and grinding the cooled raw clinker cake to obtain a cement clinker.

7. The method of claim 6, wherein in (1), the raw materials are ground to a particle size of ?0.075 mm; or the ground raw materials are thoroughly mixed for 6-9 hours using a mixer.

8. The method of claim 7, wherein in (2), calcining the raw clinker cake comprises heating the raw clinker cake to a temperature of 1200-1250? C. at a heating rate of 5-10? C./min, and maintaining the temperature for 60-120 minutes.

9. Belite-ye'elimite-ternesite cement, comprising the belite-ye'elimite-ternesite cement clinker of claim 1 or the belite-ye'elimite-ternesite cement clinker prepared by the method of claim 6, and calcium sulfate.

10. The cement of claim 9, wherein an amount of calcium sulfate is calculated according to a molar ratio of ye'elimite within the cement clinker to SO.sub.3 contained in the calcium sulfate and subtracting the amount of free-calcium sulfate (f-C$) in the cement clinker; the molar ratio of ye'elimite within the cement clinker to SO.sub.3 contained in calcium sulfate is determined according to the specification of the cement; and/or, the calcium sulfate comprises phosphogypsum, gypsum, anhydrite, desulfurization gypsum, or a combination thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0059] FIG. 1 shows an XRD pattern of a cement clinker according to Example 1 of the disclosure. Herein, Y for Ye'elimite (C.sub.4A.sub.3$), T for Ternesite (C.sub.5S.sub.2$), B1 for Belite (?-C.sub.2S), B2 for Belite (?-C.sub.2S), and A for Anhydride (C$);

[0060] FIG. 2 shows an XRD pattern of a cement clinker according to Example 2 of the disclosure. Herein, Y for Ye'elimite (C.sub.4A.sub.3$), T for Ternesite (C.sub.5S.sub.2$), B1 for Belite (?-C.sub.2S), B2 for Belite (?-C.sub.2S), and A for free-anhydride (f-C$);

[0061] FIG. 3 shows an XRD pattern of a cement clinker according to Example 3 of the disclosure. Herein, Y for Ye'elimite (C.sub.4A.sub.3$), T for Ternesite (C.sub.5S.sub.2$), B1 for Belite (?-C.sub.2S), B2 for Belite (?-C.sub.2S), and A for free-anhydride (f-C$);

[0062] FIG. 4 shows an XRD pattern of a cement clinker according to Example 4 of the disclosure. Herein, Y for Ye'elimite (C.sub.4A.sub.3$), T for Ternesite (C.sub.5S.sub.2$), B1 for Belite (?-C.sub.2S), B2 for Belite (?-C.sub.2S), and A for free-anhydride (f-C$);

[0063] FIG. 5 shows an XRD pattern of a cement clinker according to Example 5 of the disclosure. Herein, Y for Ye'elimite (C.sub.4A.sub.3$), T for Ternesite (C.sub.5S.sub.2$), B1 for Belite (?-C.sub.2S), B2 for Belite (?-C.sub.2S), and A for free-anhydride (f-C$);

[0064] FIG. 6 shows an XRD pattern of a cement clinker according to Example 6 of the disclosure. Herein, Y for Ye'elimite (C.sub.4A.sub.3$), T for Ternesite (C.sub.5S.sub.2$), B1 for Belite (?-C.sub.2S), B2 for Belite (?-C.sub.2S), and A for free-anhydride (f-C$);

[0065] FIG. 7 shows an XRD pattern of a cement clinker according to Comparison Example 1 of the disclosure. Herein, Y for Ye'elimite (C.sub.4A.sub.3$), T for Ternesite (C.sub.5S.sub.2$), B1 for Belite (?-C.sub.2S), B2 for Belite (?-C.sub.2S), and A for free-anhydride (f-C$);

[0066] FIG. 8 shows an XRD pattern of a cement clinker according to Comparison Example 2 of the disclosure. Herein, Y for Ye'elimite (C.sub.4A.sub.3$), T for Ternesite (C.sub.5S.sub.2$), B1 for Belite (?-C.sub.2S), B2 for Belite (?-C.sub.2S), and A for free-anhydride (f-C$); and

[0067] FIG. 9 shows mortar strengths at different time point (1-day, 3-day, 7-day, 28-day, and 90-day) of the cement prepared in Examples 1-6 and Comparison Examples 1-2, and a reference cement.

DETAILED DESCRIPTION

[0068] To further illustrate the disclosure, embodiments detailing a belite-ye'elimite-ternesite cement clinker and a method for preparing the same are described below. It should be noted that the following embodiments are intended to describe and not to limit the disclosure.

[0069] For embodiments lacking specific experimental details, standard procedures as described in the field's literature can be used. Unspecified materials or instruments are common products available for purchase.

[0070] In the following examples and comparisons, Table 1 lists the main chemical compositions of raw materials. These listed materials are exemplars and should not be viewed as constraints on the disclosure.

TABLE-US-00001 TABLE 1 Main chemical composition of raw materials Loss on SiO.sub.2 Al.sub.2O.sub.3 Fe.sub.2O.sub.3 CaO MgO SO.sub.3 Ignition (wt. (wt. (wt. (wt. (wt. (wt. (LOI) %) %) %) %) %) %) Limestone 42.64 0.61 0.05 0.19 55.9 0.01 0.42 Phospho- 15.45 1.44 1.19 0.62 33.93 0.31 47.04 gypsum Fly ash 2.32 52.47 34.02 2.92 4.80 0.69 0.27 Low-grade 16.00 21.72 52.40 7.63 / / / bauxite Alumina ash ?6.01 27.20 56.16 12.49 5.62 2.80 0.78 High-alumina 2.16 40.24 48.30 2.70 3.17 0.03 0.64 fly ash

Example 1

[0071] A belite-ye'elimite-ternesite cement clinker comprises the following raw materials:

[0072] 460 g of limestone, 260 g of phosphogypsum, 70 g of fly ash, and 210 g of low-grade bauxite. The main chemical compositions of each raw material were listed in Table 1.

[0073] A method for preparing the belite-ye'elimite-ternesite cement clinker, and the method comprises: [0074] (1) the raw materials were dried at 105? C. for 24 hours to remove moisture, then finely ground using a grinder to a particle size of ?0.075 mm; the ground raw materials were weighted based on the amounts described above and mixed in a mixer for 7.5 hours to form a raw mixture; [0075] (2) 14 mL of alcohol was added to 200 g of the raw mixture and mixed thoroughly; the resulting mixture was placed into a grinding and pressing machine and compressed under a pressure of 20 MPa to form a corrugated circular disk with a diameter of 10 cm and a thickness of 0.8 cm; the corrugated circular disk was then dried in a drying oven at 105? C. for 6 hours to produce a raw clinker cake; [0076] (3) the raw clinker cake was subjected to high-temperature heating using an electric furnace with a silicon molybdenum rod; the temperature was gradually raised to 1230? C. at a rate of 9.9? C./min and held at the temperature for 80 minutes; subsequently, the calcined clinker cake was quickly cooled to room temperature using forced air, thereby producing a clinker block; and [0077] (4) the cooled clinker block was crushed and ground to a fineness of 0.045 mm, ensuring that no more than 9% of the residue remained on a sieve, thereby obtaining a belite-ye'elimite-ternesite cement clinker.

[0078] Using the Topas software, the composition of the cement clinker obtained in Example 1 was determined as follows: ye'elimite at 38.97 wt. %, ternesite at 42.18 wt. %, belite at 10.49 wt. %, and free-calcium sulfate (f-C$) at 4.32 wt. %.

[0079] Within the cement clinker, the proportion of cubic ye'elimite within the cement clinker was 9.95 wt. %; the proportion of ?-C.sub.2S within the cement clinker was 2.34 wt. %; the mass ratio of belite to ternesite was 0.25; and the mass ratio of ternesite to ye'elimite was 1.08.

[0080] Example 1 further provides a method for preparing a belite-ye'elimite-ternesite cement, and the method is described as follows: 150 g of the cement clinker obtained in Example 1 was blend with 0.05 g of phosphogypsum (with an SO.sub.3 content of 47.04 wt. %); the molar ratio of ye'elimite within the cement clinker to SO.sub.3 in phosphogypsum was maintained at 2:1; and the amount of phosphogypsum to be added was determined by subtracting the amount of free-calcium sulfate (f-C$) in the cement clinker from the molar ratio of 2:1.

Example 2

[0081] A belite-ye'elimite-ternesite cement clinker comprises the following raw materials:

[0082] 490 g of limestone, 220 g of phosphogypsum, 90 g of fly ash, and 200 g of low-grade bauxite. The main chemical compositions of each raw material were listed in Table 1.

[0083] A method for preparing the belite-ye'elimite-ternesite cement clinker, and the method comprises: [0084] (1) the raw materials were dried at 105? C. for 24 hours to remove moisture, then finely ground using a grinder to a particle size of ?0.075 mm; the ground raw materials were weighted based on the amounts described above and mixed in a mixer for 6 hours to form a raw mixture; [0085] (2) 14 mL of alcohol was added to 200 g of the raw mixture and mixed thoroughly; the resulting mixture was placed into a grinding and pressing machine and compressed under a pressure of 20 MPa to form a corrugated circular disk with a diameter of 10 cm and a thickness of 0.7 cm; the corrugated circular disk was then dried in a drying oven at 105? C. for 6 hours to produce a raw clinker cake; [0086] (3) the raw clinker cake was subjected to high-temperature heating using an electric furnace with a silicon molybdenum rod; the temperature was gradually raised to 1250? C. at a rate of 5? C./min and held at the temperature for 120 minutes; subsequently, the calcined clinker cake was quickly cooled to room temperature using forced air, thereby producing a clinker block; and [0087] (4) the cooled clinker block was crushed and ground to a fineness of 0.045 mm, ensuring that no more than 9% of the residue remained on a sieve, thereby obtaining a belite-ye'elimite-ternesite cement clinker.

[0088] Using the Topas software, the composition of the cement clinker obtained in Example 2 was determined as follows: ye'elimite at 40.96 wt. %, ternesite at 33.29 wt. %, belite at 16.86 wt. %, and free-calcium sulfate (f-C$) at 4.32 wt. %.

[0089] Within the cement clinker, the proportion of cubic ye'elimite within the cement clinker was 10.80 wt. %; the proportion of ?C.sub.2S within the cement clinker was 1.38 wt. %; the mass ratio of C.sub.2S to ternesite was 0.51; and the mass ratio of ternesite to ye'elimite was 0.81.

[0090] Example 2 further provides a method for preparing a belite-ye'elimite-ternesite cement, and the method is described as follows: 150 g of the cement clinker obtained in Example 2 was blend with 0.92 g of gypsum (with an SO.sub.3 content of 23.69 wt. %); the molar ratio of ye'elimite within the cement clinker to SO.sub.3 in gypsum was maintained at 2:1; and the amount of gypsum to be added was determined by subtracting the amount of free-calcium sulfate (f-C$) in the cement clinker from the molar ratio of 2:1.

Example 3

[0091] A belite-ye'elimite-ternesite cement clinker comprises the following raw materials:

[0092] 520 g of limestone, 200 g of phosphogypsum, 120 g of fly ash, and 180 g of low-grade bauxite. The main chemical compositions of each raw material were listed in Table 1.

[0093] A method for preparing the belite-ye'elimite-ternesite cement clinker, and the method comprises: [0094] (1) the raw materials were dried at 105? C. for 24 hours to remove moisture, then finely ground using a grinder to a particle size of ?0.075 mm; the ground raw materials were weighted based on the amounts described above and mixed in a mixer for 9 hours to form a raw mixture; [0095] (2) 14 mL of alcohol was added to 200 g of the raw mixture and mixed thoroughly; the resulting mixture was placed into a grinding and pressing machine and compressed under a pressure of 20 MPa to form a corrugated circular disk with a diameter of 10 cm and a thickness of 0.5 cm; the corrugated circular disk was then dried in a drying oven at 105? C. for 6 hours to produce a raw clinker cake; [0096] (3) the raw clinker cake was subjected to high-temperature heating using an electric furnace with a silicon molybdenum rod; the temperature was gradually raised to 1210? C. at a rate of 7.5? C./min and held at the temperature for 60 minutes; subsequently, the calcined clinker cake was quickly cooled to room temperature using forced air, thereby producing a clinker block; and [0097] (4) the cooled clinker block was crushed and ground to a fineness of 0.045 mm, ensuring that no more than 9% of the residue remained on a sieve, thereby obtaining a belite-ye'elimite-ternesite cement clinker.

[0098] Using the Topas software, the composition of the cement clinker obtained in Example 3 was determined as follows: ye'elimite at 42.89 wt. %, ternesite at 24.8 wt. %, belite at 24.52 wt. %, and free-calcium sulfate (f-C$) at 3.64 wt. %.

[0099] Within the cement clinker, the proportion of cubic ye'elimite within the cement clinker was 13.28 wt. %; the proportion of ?-C.sub.2S within the cement clinker was 1.77 wt. %; the mass ratio of belite to ternesite was 0.99; and the mass ratio of ternesite to ye'elimite was 0.58.

[0100] Example 3 further provides a method for preparing a belite-ye'elimite-ternesite cement, and the method is described as follows: 150 g of the cement clinker obtained in Example 3 was blend with 2.06 g of anhydrite (with an SO.sub.3 content of 48.89 wt. %); the molar ratio of ye'elimite within the cement clinker to SO.sub.3 in anhydrite was maintained at 2:1; and the amount of anhydrite to be added was determined by subtracting the amount of free-calcium sulfate (f-C$) in the cement clinker from the molar ratio of 2:1.

Example 4

[0101] A belite-ye'elimite-ternesite cement clinker comprises the following raw materials:

[0102] 520 g of limestone, 200 g of phosphogypsum, 100 g of fly ash, and 180 g of alumina ash. The main chemical compositions of each raw material were listed in Table 1.

[0103] A method for preparing the belite-ye'elimite-ternesite cement clinker, and the method comprises: [0104] (1) the raw materials were dried at 105? C. for 24 hours to remove moisture, then finely ground using a grinder to a particle size of ?0.075 mm; the ground raw materials were weighted based on the amounts described above and mixed in a mixer for 8 hours to form a raw mixture; [0105] (2) 14 mL of alcohol was added to 200 g of the raw mixture and mixed thoroughly; the resulting mixture was placed into a grinding and pressing machine and compressed under a pressure of 20 MPa to form a corrugated circular disk with a diameter of 10 cm and a thickness of 0.9 cm; the corrugated circular disk was then dried in a drying oven at 105? C. for 6 hours to produce a raw clinker cake; [0106] (3) the raw clinker cake was subjected to high-temperature heating using an electric furnace with a silicon molybdenum rod; the temperature was gradually raised to 1240? C. at a rate of 6? C./min and held at the temperature for 110 minutes; subsequently, the calcined clinker cake was quickly cooled to room temperature using forced air, thereby producing a clinker block; and [0107] (4) the cooled clinker block was crushed and ground to a fineness of 0.045 mm, ensuring that no more than 9% of the residue remained on a sieve, thereby obtaining a belite-ye'elimite-ternesite cement clinker.

[0108] Using the Topas software, the composition of the cement clinker obtained in Example 4 was determined as follows: ye'elimite at 37.23 wt. %, ternesite at 39.23 wt. %, belite at 14.71 wt. %, and free-calcium sulfate (f-C$) at 4.12 wt. %.

[0109] Within the cement clinker, the proportion of cubic ye'elimite within the cement clinker was 9.18 wt. %; the proportion of ?-C.sub.2S within the cement clinker was 1.68 wt. %; the mass ratio of belite to ternesite was 0.40; and the mass ratio of ternesite to ye'elimite was 1.05.

[0110] Example 4 further provides a method for preparing a belite-ye'elimite-ternesite cement, and the method is described as follows: 200 g of the cement clinker obtained in Example 4 was blend with 0.17 g of desulfogypsum (with an SO.sub.3 content of 21.47 wt. %); the molar ratio of ye'elimite within the cement clinker to SO.sub.3 in desulfogypsum was maintained at 2:1; and the amount of desulfogypsum to be added was determined by subtracting the amount of free-calcium sulfate (f-C$) in the cement clinker from the molar ratio of 2:1.

Example 5

[0111] A belite-ye'elimite-ternesite cement clinker comprises the following raw materials:

[0112] 570 g of limestone, 210 g of phosphogypsum, 60 g of fly ash, and 200 g of high-alumina fly ash. The main chemical compositions of each raw material were listed in Table 1.

[0113] A method for preparing the belite-ye'elimite-ternesite cement clinker, and the method comprises: [0114] (1) the raw materials were dried at 105? C. for 24 hours to remove moisture, then finely ground using a grinder to a particle size of ?0.075 mm; the ground raw materials were weighted based on the amounts described above and mixed in a mixer for 7 hours to form a raw mixture; [0115] (2) 14 mL of alcohol was added to 200 g of the raw mixture and mixed thoroughly; the resulting mixture was placed into a grinding and pressing machine and compressed under a pressure of 20 MPa to form a corrugated circular disk with a diameter of 10 cm and a thickness of 1 cm; the corrugated circular disk was then dried in a drying oven at 105? C. for 6 hours to produce a raw clinker cake; [0116] (3) the raw clinker cake was subjected to high-temperature heating using an electric furnace with a silicon molybdenum rod; the temperature was gradually raised to 1220? C. at a rate of 8.5? C./min and held at the temperature for 100 minutes; subsequently, the calcined clinker cake was quickly cooled to room temperature using forced air, thereby producing a clinker block; and [0117] (4) the cooled clinker block was crushed and ground to a fineness of 0.045 mm, ensuring that no more than 9% of the residue remained on a sieve, thereby obtaining a belite-ye'elimite-ternesite cement clinker.

[0118] Using the Topas software, the composition of the cement clinker obtained in Example 5 was determined as follows: ye'elimite at 37.89 wt. %, ternesite at 40.06 wt. %, belite at 13.85 wt. %, and free-calcium sulfate (f-C$) at 2.07 wt. %.

[0119] Within the cement clinker, the proportion of cubic ye'elimite within the cement clinker was 9.21 wt. %; the proportion of ?-C.sub.2S within the cement clinker was 1.51 wt. %; the mass ratio of belite to ternesite was 0.35; and the mass ratio of ternesite to ye'elimite was 1.06.

[0120] Example 5 further provides a method for preparing a belite-ye'elimite-ternesite cement, and the method is described as follows: 200 g of the cement clinker obtained in Example 5 was blend with 5.39 g of phosphogypsum (with an SO.sub.3 content of 47.04 wt. %); the molar ratio of ye'elimite within the cement clinker to SO.sub.3 in phosphogypsum was maintained at 2:1; and the amount of phosphogypsum to be added was determined by subtracting the amount of free-calcium sulfate (f-C$) in the cement clinker from the molar ratio of 2:1.

Example 6

[0121] A belite-ye'elimite-ternesite cement clinker comprises the following raw materials:

[0122] 490 g of limestone, 220 g of phosphogypsum, 90 g of fly ash, and 200 g of low-grade bauxite. The main chemical compositions of each raw material were listed in Table 1.

[0123] A method for preparing the belite-ye'elimite-ternesite silicate cement clinker, and the method comprises: [0124] (1) the raw materials were dried at 105? C. for 24 hours to remove moisture, then finely ground using a grinder to a particle size of ?0.075 mm; the ground raw materials were weighted based on the amounts described above and mixed in a mixer for 6 hours to form a raw mixture; [0125] (2) 14 mL of alcohol was added to 200 g of the raw mixture and mixed thoroughly; the resulting mixture was placed into a grinding and pressing machine and compressed under a pressure of 20 MPa to form a corrugated circular disk with a diameter of 10 cm and a thickness of 0.7 cm; the corrugated circular disk was then dried in a drying oven at 105? C. for 6 hours to produce a raw clinker cake; [0126] (3) the raw clinker cake was subjected to high-temperature heating using an electric furnace with a silicon molybdenum rod; the temperature was gradually raised to 1250? C. at a rate of 10? C./min and held at the temperature for 120 minutes; subsequently, the calcined clinker cake was quickly cooled to room temperature using forced air, thereby producing a clinker block; and [0127] (4) the cooled clinker block was crushed and ground to a fineness of 0.045 mm, ensuring that no more than 9% of the residue remained on a sieve, thereby obtaining a belite-ye'elimite-ternesite cement clinker.

[0128] Using the Topas software, the composition of the cement clinker obtained in Example 6 was determined as follows: ye'elimite at 41.86 wt. %, ternesite at 33.39 wt. %, belite at 17.75 wt. %, and free-calcium sulfate (f-C$) at 4.43 wt. %.

[0129] Within the cement clinker, the proportion of cubic ye'elimite within the cement clinker was 10.57 wt. %; the proportion of ?-C.sub.2S within the cement clinker was 1.34 wt. %; the mass ratio of belite to ternesite was 0.53; and the mass ratio of ternesite to ye'elimite was 0.80.

[0130] Example 6 further provides a method for preparing a belite-ye'elimite-ternesite cement, and the method is described as follows: 150 g of the cement clinker obtained in Example 6 was blend with 0.88 g of anhydrite (with an SO.sub.3 content of 23.69 wt. %); the molar ratio of ye'elimite within the cement clinker to SO.sub.3 in the anhydrite was maintained at 2:1; and the amount of anhydrite to be added was determined by subtracting the amount of free-calcium sulfate (f-C$) in the cement clinker from the molar ratio of 2:1.

Comparison Example 1

[0131] Comparison Example 1 is identical to Example 2, except for one difference:

[0132] The raw clinker cake was calcined at 1200? C.

[0133] Using the Topas software, the composition of the cement clinker obtained in Comparison Example 1 was determined as follows: ye'elimite at 35.81 wt. %, ternesite at 50.14 wt. %, belite at 10.58 wt. %, and free-calcium sulfate (f-C$) at 0.94 wt. %.

[0134] Within the cement clinker, the proportion of cubic ye'elimite within the cement clinker was 4.55 wt. %; the proportion of ?-C.sub.2S within the cement clinker was 0.74 wt. %; the mass ratio of belite to ternesite was 0.21; and the mass ratio of ternesite to ye'elimite was 1.4.

Comparison Example 2

[0135] Comparison Example 2 replicates Example 2 from Chinese Patent CN114213043A, following a specific method for preparing a cement clinker: fly ash, phosphogypsum, limestone, and bauxite were dried at 100? C. for 24 hours, then ground into particles with a fineness of ?200 mesh; a mixture containing 580 g of limestone, 103.3 g of phosphogypsum, 206.1 g of fly ash, and 110.6 g of bauxite were thoroughly blend in a mixer for 12 hours; subsequently, 20 g of the resulting mixture was compressed into a circular disc with a diameter of 20 mm under a pressure of 20 MPa; the circular disc was then placed in a box-type resistance furnace, heated to 1150? C. at a rate of 10? C./min, held for 30 minutes, and rapidly cooled using air flow; and the resulting cooled clinker block was further crushed to achieve a fineness of 200 mesh.

[0136] Utilizing the Topas software, the composition of the cement clinker obtained in Comparison Example 2 was determined as follows: ye'elimite at 34 wt. %, ternesite at 12.6 wt. %, belite at 48.5 wt. %, and mayenite at 1.10 wt. %. Within the cement clinker, the mass ratio of belite to ternesite was 3.85; and the mass ratio of ternesite to ye'elimite was 0.37. No free-calcium sulfate (f-C$), cubic ye'elimite, and ?-C.sub.2S were detected.

Experimental Example

Structural Determination

[0137] X-ray diffraction analysis was conducted on the cement clinkers prepared in Examples 1-6 and Comparison Examples 1-2, along with a reference silicate cement. The X-ray diffraction analysis was carried out using a scanning speed of 4?/min and a step size of 0.01?, and the results were shown in FIGS. 1-8.

[0138] The figures reveal that, in the cement clinkers prepared in Examples 1-6, no diffraction peaks corresponding to free calcium oxide were detected. The absence signifies the successful calcination process achieved at the given temperature. Furthermore, the cement clinkers exhibit a pronounced diffraction peak for C.sub.5S.sub.2$, indicating the successful crystallization of C.sub.5S.sub.2$ under the specific experimental conditions. Additionally, the cement clinkers comprise a highly reactive ?-C.sub.2S phase. The ?-C.sub.2S phase exhibits greater hydration reactivity compared to ?-C.sub.2S and enhances the strength development of the cement clinkers during later stages. In Comparison Example 1, the lower calcination temperature results in subdued diffraction peaks associated with free-calcium sulfate (f-C$) and belite, suggesting their conversion into ternesite through a chemical reaction. The impact of temperature ramp rate on the formation of the cement clinkers is insignificant, as demonstrated through the comparison between Examples 2 and 6. However, in Comparison Example 2, the formation of ternesite is minimal, to the point of being nearly undetectable, which differs significantly from the results observed in Examples 1-6.

[0139] Utilizing the XRD patterns, a quantitative analysis of the mineral components within the cement clinkers from Examples 1-6 and Comparison Examples 1-2 was carried out using Topas software and Rietveld full-pattern fitting. The results revealed that the levels of the mineral components in Examples 1-6 aligned with the design specifications. Notably, the content of ternesite reached 42.18 wt. %, demonstrating the feasibility of achieving stable calcination for the belite-ye'elimite-ternesite clinker. The achievement is facilitated through a single calcination process performed within the temperature range of 1210-1250? C., achieved by designing and regulating the content of phosphogypsum in the raw mixture. In comparison, Comparison Example 1 experiences a decrease in the content of cubic ye'elimite and ?-C.sub.2S due to the lower calcination temperature. Comparison Example 2 displays lower ternesite content and the presence of C.sub.12A.sub.7, while cubic ye'elimite and ?-C.sub.2S are not detected. In Examples 1-6, incorporating 2-10 wt. % free-calcium sulfate (f-C$) stimulates the generation of ye'elimite during the early stages of calcination, instead of forming mayenite, calcium aluminate, or other aluminum compounds when calcium sulfate is present. Additionally, the results of quantitative analysis suggest a rise in the proportion of the highly reactive c-C.sub.4A.sub.3$ in Examples 1-6, accounting for about ? of the total C.sub.4A.sub.3$ content. The increment contributes to the early-stage strength development of the cement clinker.

Test for Compressive Strength of Cement Mortar

[0140] A strength performance test was conducted on the cement clinkers prepared in Examples 1-6 and Comparison Examples 1-2. The resulting cements, derived from the cement clinkers and mixed with a water-to-cement ratio of 0.5 and a sand-to-cement ratio of 3, underwent a test for compressive strength of cement mortar. A reference cement is obtained through combining Portland cement clinker and anhydrite. The reference cement underwent identical test for compressive strength of cement mortar, employing the same water-to-cement ratio and sand-to-cement ratio. The resulting cement mortars were placed within a curing chamber with a constant temperature of 20? C. and a relative humidity of 95%. Subsequently, the compressive strengths of the cement mortars were evaluated at various time intervals. The results for cement mortars at 1 day, 3 days, 7 days, 28 days, and 90 days are detailed in Table 2 and FIG. 9.

TABLE-US-00002 TABLE 2 Mortar strength of belite-ye'elimite-ternesite cement prepared in Examples and Comparison Examples, compared to reference cement Mortar compressive strength/MPa Reference Age/d cement Example 1 Example 2 Example 3 Example 4 1 17.2 32.3 33.4 34.2 33.1 3 32.3 36.4 41.3 42.6 37.9 7 41.6 37.2 42.8 44.6 40.8 28 52.2 51.2 55.2 58.1 52.4 90 62.3 65.8 67.7 69.1 63.7 Mortar compressive strength/MPa Comparison Comparison Age/d Example 5 Example 6 Example 1 Example 2 1 32.8 33.7 30.1 25.4 3 37.8 42.3 33.1 26.9 7 39.2 42.8 35.3 27.6 28 53.7 54.2 51.1 42.6 90 64.1 66.7 60.1 55.3

[0141] The data from Table 2 and FIG. 9, demonstrate that the compressive strengths of the belite-ye'elimite-ternesite cement clinkers, as prepared in Examples 1-6 show significant superiority over those of the reference cement at both 1 day and 3 days. Notably, in Examples 3 and 6, the strengths at 3 days match the 7-day strength of the reference cement. Furthermore, when considering the cement clinkers prepared in Examples 2-6, the strengths at 28 days exceed that of the reference cement, with the exception of Example 1, which shows a slightly lower value. Nevertheless, as time progresses, the cement clinkers prepared in Examples 1-6 exhibit a gradual strengthening effect, eventually surpassing the reference cement in compressive strength at 90 days. The cement clinkers from Examples 2, 3, and 6 demonstrate enhanced strength compared to Examples 1, 4, and 5. This phenomenon can be linked to the theoretically greater reactivity of ternesite compared to belite, where a higher content of ternesite typically corresponds to improved strength performance. However, due to the collaboration hydration process of minerals within the system, there is an optimal range for the mass ratio of belite to ternesite, which lies between 0.25 and 1. Similarly, the mass ratio of ternesite to ye'elimite falls between 0.5 to 1 to achieve optimal strength. Deviating from the ranges often leads to a reduction in strength. Comparison Example 1 shows lower strength, indicating a slightly weaker performance of the cement clinkers calcined at 1200? C. Compared to Comparison Example 2, the strength of the cement prepared using the methods of Examples 1-6 has experienced an enhancement. This improvement highlights a specific performance advantage as described in the disclosure.

[0142] It will be obvious to those skilled in the art that changes and modifications may be made, and therefore, the aim in the appended claims is to cover all such changes and modifications.