Belite sulphoaluminate cement and low-temperature preparation method thereof

Abstract

The invention relates to belite sulphoaluminate cement, the mass ratio of belite sulphoaluminate cement clinker to gypsum in the cement is (93-100): (0.5-7), the doping amount of gypsum is small, calcium sulphoaluminate can be promoted to be hydrated to generate more alumina gel, the alumina gel and dicalcium silicate generate hydrated calcium aluminosilicate, and the calcium aluminosilicate and dicalcium silicate are mixed to generate calcium aluminosilicate. Meanwhile, calcium sulphoaluminate is promoted to be hydrated to generate less ettringite and part of monosulfur hydrated calcium sulphoaluminate, and the early strength and the later strength of the cement are remarkably improved; the invention further relates to a low-temperature preparation method of the belite sulphoaluminate cement, the calcination temperature of the raw material is 1120-1200 DEG C and is lower than the calcination temperature in the prior art, and the preparation energy consumption of the cement clinker is reduced; according to the present invention, the early strength of the cement prepared through the calcination at the temperature of the present invention develops rapidly, the later strength of the cement slurry does not shrink with the increase of the hydration age, and the cement slurry still presents the stable increase trend, and the calcination temperature can increase the crystal defect of the calcium sulphoaluminate so as to easily provide the hydration activity of the calcium sulphoaluminate.

Description

Technical Field

[0001] The invention belongs to the technical field of special cements, and in particular relates to a belite sulphoaluminate cement and a low-temperature preparation method thereof. Background Art

[0002] As an important specialty cement, sulphoaluminate cement offers unique advantages, including rapid early strength and hardening, minimal expansion, strong resistance to sulfate attack, and a relatively low firing temperature (1250-1350°C). It is therefore particularly valuable in emergency repair projects, marine engineering, low-temperature construction, and the utilization of industrial waste. However, sulphoaluminate cement production requires large quantities of high-grade bauxite, a relatively scarce and expensive resource. This has significantly increased production costs, severely restricting its application and development.

[0003] In order to reduce the production cost of sulphoaluminate cement, researchers have developed Belite Sulphoaluminate Cement, which optimizes the mineral composition of ordinary sulphoaluminate cement, significantly increasing the content of dicalcium silicate while moderately reducing the content of calcium sulphoaluminate. However, due to the reduced content of calcium sulphoaluminate, the overall hydration of high Belite Sulphoaluminate Cement is slower, and it no longer has the early strength advantage of sulphoaluminate cement. In addition, dicalcium silicate, as the main mineral in Belite Sulphoaluminate Cement clinker, has a slow hydration rate and is the main contributor to the later strength of cement. However, due to the hydration of calcium sulphoaluminate and its product ettringite, the hydration activity of dicalcium silicate is difficult to be effectively exerted, resulting in slow growth in the later strength of Belite Sulphoaluminate Cement. Existing technologies change the crystal structure of dicalcium silicate by ion doping to improve its hydration activity, but this method of changing the activity of dicalcium silicate is still limited. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a belite sulphoaluminate cement and a low-temperature preparation method thereof.

[0005] The technical solution of the present invention is: A low-temperature preparation method of belite sulphoaluminate cement comprises the following steps: S1. Preparation of cement clinker: The raw materials of the Belite sulphoaluminate cement clinker were ground to obtain cement raw material; the raw materials were mixed, pressed and dried to obtain a raw cake, which was calcined and cooled to room temperature to obtain Belite sulphoaluminate cement clinker; S2. Preparation of Belite Sulphoaluminate Cement: The cement clinker is mixed with raw gypsum and ground to obtain Belite Sulphoaluminate Cement.

[0006] Furthermore, the mass ratio of the belite sulphoaluminate cement clinker in step S1 to the raw gypsum in step S2 is (93-100):(0.5-7).

[0007] Furthermore, the raw materials of the belite sulphoaluminate cement clinker in step S1 include, by mass, 82-96 parts of limestone, 6-17 parts of raw gypsum, 5-28 parts of bauxite, 18-42 parts of fly ash, and 0-0.5 parts of calcium fluoride.

[0008] Furthermore, the content of Al2O3 in the bauxite is 55-70wt.%.

[0009] Furthermore, the mineral phase of the belite sulphoaluminate cement clinker in step S1 includes the following components in parts by mass: 45-70 parts of dicalcium silicate, 25-40 parts of calcium sulphoaluminate, 2-10 parts of tetracalcium aluminoferrite, 0-5 parts of calcium sulphosilicate, and 0-5 parts of high-temperature anhydrite.

[0010] Furthermore, the raw materials of the belite sulphoaluminate cement clinker in step S1 are ground and then passed through a 100-200 mesh sieve.

[0011] Furthermore, the calcination temperature in step S1 is 1120-1200° C., and the holding time is 20-60 min.

[0012] Furthermore, in step S2, the cement clinker is mixed with raw gypsum, ground and then passed through a 100-200 mesh sieve.

[0013] Furthermore, the specific surface area of ​​the belite sulphoaluminate cement in step S2 is 320-380 m 2 / kg.

[0014] Belite sulphoaluminate cement prepared according to the low-temperature preparation method.

[0015] Compared with the prior art, the present invention has at least the following advantages: 1. The present invention relates to a belite sulphoaluminate cement, wherein the mass ratio of belite sulphoaluminate cement clinker to raw gypsum in the belite sulphoaluminate cement is (93-100):(0.5-7), and the physical phase of the belite sulphoaluminate cement clinker comprises 45-70 parts of dicalcium silicate, 25-40 parts of calcium sulphoaluminate, 2-10 parts of tetracalcium aluminoferrite, 0-5 parts of calcium sulphosilicate, and 0-5 parts of high-temperature anhydrite; the raw gypsum content in the belite sulphoaluminate cement is relatively low, which can promote the hydration of calcium sulphoaluminate to generate more alumina and less ettringite and part of monosulfide water. Calcium sulphoaluminate, alumina gel is an intermediate product of cement hydration, existing in the form of amorphous Al(OH)3 or low-crystallinity hydrated alumina (Al2O3﹒nH2O), and has high reactivity. Further, alumina gel and dicalcium silicate generate hydrated calcium aluminosilicate. Hydrated calcium aluminosilicate has a layered structure, which can fill pores and increase density, significantly improving the early and late strength of Belite sulphoaluminate cement. The chemically bound water content of the cement paste of the finished Belite sulphoaluminate cement was analyzed, and it was found that the chemically bound water content of the finished Belite sulphoaluminate cement was high and the hydration activity was improved.

[0016] 2. The present invention relates to a low-temperature preparation method for belite sulphoaluminate cement. In the low-temperature preparation method, the raw material calcination temperature is 1120-1200°C, which is lower than the calcination temperature in the prior art. This reduces the energy consumption of preparing belite sulphoaluminate cement clinker and protects the environment. Compressive strength tests of cement pastes at different ages show that the early strength of the belite sulphoaluminate cement calcined at the temperature of the present invention develops rapidly, and the late strength of the cement paste does not decrease with the increase of hydration age, but continues to show a stable growth trend. The calcination temperature can increase the crystal defects of calcium sulphoaluminate, which is more conducive to the hydration activity of calcium sulphoaluminate. In the low-temperature preparation method of the belite sulphoaluminate cement of the present invention, the raw materials of the belite sulphoaluminate cement raw material contain calcium fluoride. The introduction of calcium fluoride ion doping increases the crystal defects of calcium sulphoaluminate and dicalcium silicate, improves the burnability of the raw material, further improves the hydration activity of calcium sulphoaluminate and dicalcium silicate, and enhances the mechanical properties of the belite sulphoaluminate cement. The method has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention, the following briefly introduces the drawings required for the specific embodiments or the description of the prior art.

[0018] Figure 1 This is the XRD pattern of the Belite sulphoaluminate cement clinker prepared in Example 1; Figure 2 This is the XRD pattern of the Belite sulphoaluminate cement clinker prepared in Example 2; Figure 3This is the XRD pattern of the Belite sulphoaluminate cement clinker prepared in Example 3; Figure 4 This is the XRD pattern of the belite sulphoaluminate cement clinker prepared in Comparative Example 2; Figure 5 This is the XRD pattern of the hydration product of the Belite sulphoaluminate cement paste obtained in Example 1; Figure 6 This is the XRD pattern of the hydration product of the Belite sulphoaluminate cement paste obtained in Example 2; Figure 7 This is the XRD pattern of the hydration product of the Belite sulphoaluminate cement paste obtained in Example 3; Figure 8 This is the XRD pattern of the hydration product of the Belite sulphoaluminate cement paste obtained in Comparative Example 1; Figure 9 The compressive strength of the belite sulphoaluminate cement paste at different ages prepared in Examples 1-3 and Comparative Examples 1-2; Figure 10 Graph showing the relationship between the chemically bound water content at 90 days of age and the strength of the belite sulphoaluminate cement pastes obtained in Examples 1-3 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0019] The present invention is described in further detail below. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above application content.

[0020] This document provides general and / or specific descriptions of the materials and experimental methods used in the experiments. Unless otherwise specified, all experimental or testing methods are conventional methods. All reagents and instruments used, unless the manufacturer is specified, are commercially available, conventional products and were prepared or used using conventional methods.

[0021] When expressing a certain amount, concentration or other value or parameter in the form of a range, preferred range, or preferred upper and lower numerical limits, it should be understood that it is equivalent to specifically disclosing any range by combining any pair of upper range limits or preferred numerical values ​​with any lower range limit or preferred numerical value, without considering whether the range is specifically disclosed. Unless otherwise indicated, the numerical range values ​​listed herein include the endpoints of the range and all integers and fractions within the range.

[0022] Example 1 A low-temperature preparation method of belite sulphoaluminate cement comprises the following steps: S1. Preparation of Belite Sulphoaluminate Cement Raw Material: Limestone, bauxite, fly ash and gypsum were dried and ground to a powder with a fineness of 140 mesh. 84.78 parts of limestone, 24.92 parts of bauxite, 19.97 parts of fly ash, 15.13 parts of gypsum and 0.3 parts of calcium fluoride were mixed to obtain cement raw material powder; 10 wt.% water was added to the cement raw material, pressed into a cake in a mold, and dried at 105 ° C to obtain a raw material cake; S2. Calcination of Belite Sulphoaluminate Cement Clinker: The raw cake obtained in step S1 was calcined in a high-temperature furnace at a temperature of 1150°C for 30 min. After calcination, the raw cake was removed from the high-temperature furnace and rapidly cooled to room temperature with a blast to obtain Belite Sulphoaluminate Cement Clinker. S3. Preparation of Belite Sulphoaluminate Cement: The Belite Sulphoaluminate Cement clinker obtained in step S2 was mixed with 0.5 wt.% raw gypsum, ground in a ball mill, and the particles were passed through a 200-mesh square sieve to obtain Belite Sulphoaluminate Cement. The specific surface area of ​​the Belite Sulphoaluminate Cement powder reached 340 m 2 / kg.

[0023] The XRD pattern of the Belite sulphoaluminate cement prepared in this example is shown in FIG. Figure 1 As shown in the figure, the phase composition of Belite sulfoaluminate cement clinker is composed of dicalcium silicate (C2S), calcium sulfoaluminate, tetracalcium aluminoferrite (C4AF), calcium sulfosilicate (C5S2S), and high-temperature anhydrite. Rietveld quantitative analysis reveals that the proportions of each mineral are 49.4 wt.% dicalcium silicate, 38.3 wt.% calcium sulfoaluminate, 6.5 wt.% tetracalcium aluminoferrite, 1.9 wt.% calcium sulfosilicate, and 3.9 wt.% high-temperature anhydrite.

[0024] Example 2 A low-temperature preparation method of belite sulphoaluminate cement comprises the following steps: S1. Preparation of Belite Sulphoaluminate Cement Raw Meal: Limestone, bauxite, fly ash, and gypsum were dried and ground to a 120-mesh powder. 94.71 parts of limestone, 6.92 parts of bauxite, 39.79 parts of fly ash, 7.72 parts of gypsum, and 0.3 parts of calcium fluoride were mixed to obtain cement raw meal powder. 10 wt.% water was added to the cement raw meal, pressed into a cake in a mold, and dried at 105°C to obtain a raw meal cake. S2. Calcination of Belite Sulphoaluminate Cement Clinker: The raw cake obtained in step S1 was calcined in a high-temperature furnace at a temperature of 1170°C for 45 minutes. After calcination, the raw cake was removed from the high-temperature furnace and rapidly cooled to room temperature with a blast to obtain Belite Sulphoaluminate Cement Clinker. S3. Preparation of Belite Sulphoaluminate Cement: The Belite Sulphoaluminate Cement clinker obtained in step S2 was mixed with 2 wt.% raw gypsum, ground in a ball mill, and the particles were passed through a 200-mesh square sieve to obtain Belite Sulphoaluminate Cement. The specific surface area of ​​the Belite Sulphoaluminate Cement powder reached 350 m 2 / kg.

[0025] The XRD pattern of the Belite sulphoaluminate cement prepared in this example is shown in FIG. Figure 2 As shown in the figure, it can be seen that the phase composition of Belite sulphoaluminate cement clinker is dicalcium silicate (C2S), calcium sulphoaluminate, tetracalcium aluminoferrite (C4AF), calcium sulphosilicate (C5S2S), and high-temperature anhydrite.

[0026] Example 3 A low-temperature preparation method of belite sulphoaluminate cement comprises the following steps: S1. Preparation of Belite Sulphoaluminate Cement Raw Material: Limestone, bauxite, fly ash, and gypsum were dried and ground to a powder with a fineness of 170 mesh. 87.79 parts of limestone, 14.78 parts of bauxite, 30.61 parts of fly ash, 14.05 parts of gypsum, and 0.5 parts of calcium fluoride were mixed to obtain cement raw material powder; 10 wt.% water was added to the cement raw material, pressed into a cake in a mold, and dried at 105°C to obtain a raw material cake; S2. Calcination of Belite Sulphoaluminate Cement Clinker: The raw cake obtained in step S1 is calcined in a high-temperature furnace at a temperature of 1180°C for 60 min. After calcination, the raw cake is removed from the high-temperature furnace and rapidly cooled to room temperature by blasting to obtain Belite Sulphoaluminate Cement Clinker.

[0027] S3. Preparation of Belite Sulphoaluminate Cement: The Belite Sulphoaluminate Cement clinker obtained in step S2 was mixed with 5 wt.% raw gypsum, ground in a ball mill, and the particles were passed through a 200-mesh square-hole sieve to obtain Belite Sulphoaluminate Cement. The specific surface area of ​​the Belite Sulphoaluminate Cement powder reached 360 m 2 / kg.

[0028] The XRD pattern of the Belite sulphoaluminate cement prepared in this example is shown in FIG. Figure 3 As shown in the figure, it can be seen that the phase composition of Belite sulphoaluminate cement clinker is dicalcium silicate (C2S), calcium sulphoaluminate, tetracalcium aluminoferrite (C4AF), and high-temperature anhydrite.

[0029] Comparative Example 1 This comparative example provides a low-temperature preparation method of belite sulphoaluminate cement, which is basically the same as Example 1, except that in step S3, cement clinker is mixed with 10 wt.% raw gypsum. The preparation method is specifically as follows.

[0030] S1. Preparation of Belite Sulphoaluminate Cement Raw Material: After drying limestone, bauxite, fly ash and gypsum, they were ground to a powder with a fineness of 140 mesh. 84.78 parts of limestone, 24.92 parts of bauxite, 19.97 parts of fly ash, 15.13 parts of gypsum and 0.3 parts of calcium fluoride were mixed to obtain cement raw material powder; 10 wt.% water was added to the cement raw material, pressed into a cake in a mold, and dried at 105 ° C to obtain a raw material cake; S2. Calcination of Belite Sulphoaluminate Cement Clinker: The raw cake obtained in step S1 was calcined in a high-temperature furnace at a temperature of 1150°C for 30 min. After calcination, the raw cake was removed from the high-temperature furnace and rapidly cooled to room temperature with a blast to obtain Belite Sulphoaluminate Cement Clinker. S3. Preparation of Belite Sulphoaluminate Cement: The Belite Sulphoaluminate Cement clinker obtained in step S2 was mixed with 10 wt.% raw gypsum, ground in a ball mill, and the particles were passed through a 200-mesh square sieve to obtain Belite Sulphoaluminate Cement. The specific surface area of ​​the Belite Sulphoaluminate Cement powder reached 340 m 2 / kg.

[0031] Comparative Example 2 This comparative example provides a low-temperature preparation method of belite sulphoaluminate cement, which is basically the same as Example 1, except that the calcination temperature in step S2 is 1250°C. The preparation method is specifically as follows.

[0032] S1. Preparation of Belite Sulphoaluminate Cement Raw Material: Limestone, bauxite, fly ash and gypsum were dried and ground to a powder with a fineness of 140 mesh. 84.78 parts of limestone, 24.92 parts of bauxite, 19.97 parts of fly ash, 15.13 parts of gypsum and 0.3 parts of calcium fluoride were mixed to obtain cement raw material powder; 10 wt.% water was added to the cement raw material, pressed into a cake in a mold, and dried at 105 ° C to obtain a raw material cake; S2. Calcination of Belite Sulphoaluminate Cement Clinker: The raw cake obtained in step S1 was calcined in a high-temperature furnace at a temperature of 1250°C for 30 min. After calcination, the raw cake was removed from the high-temperature furnace and rapidly cooled to room temperature with a blast to obtain Belite Sulphoaluminate Cement Clinker. S3. Preparation of Belite Sulphoaluminate Cement: The Belite Sulphoaluminate Cement clinker obtained in step S2 was ground in a ball mill, and the particles were passed through a 200-mesh square sieve to obtain Belite Sulphoaluminate Cement. The specific surface area of ​​the Belite Sulphoaluminate Cement powder reached 340 m 2 / kg.

[0033] The XRD pattern of the Belite sulphoaluminate cement prepared in this example is shown in FIG. Figure 4As shown in the figure, the phase composition of Belite sulfoaluminate cement clinker is composed of dicalcium silicate (C2S), calcium sulfoaluminate, tetracalcium aluminoferrite (C4AF), high-temperature anhydrite, and sulfur-free calcium silicate. Rietveld quantitative analysis reveals that the proportions of each mineral are 50.6 wt.% dicalcium silicate, 39.7 wt.% calcium sulfoaluminate, 6.8 wt.% tetracalcium aluminoferrite, and 2.9 wt.% high-temperature anhydrite.

[0034] Test Example 1 The XRD patterns of the hydration products of the Belite sulphoaluminate cement paste prepared in Examples 1 to 3 and Comparative Example 1 are shown in FIG. Figure 5-8 As shown, from Figure 5-7 It can be seen from the results that the belite sulphoaluminate cement pastes prepared in Examples 1 to 3 began to generate a large amount of hydrated calcium silicoaluminate (Stratlingite) and monosulfate hydrated calcium sulfoaluminate (Monosulfate) after hydration for 7 days, and the diffraction peak of calcium sulfoaluminate was no longer obvious; while the hydrated calcium silicoaluminate and monosulfate hydrated calcium sulfoaluminate were absent in the hydration product of the belite sulphoaluminate cement paste prepared in Comparative Example 1; this indicates that a low amount of raw gypsum can promote the formation of calcium sulfoaluminate hydrate. More aluminum gel and less ettringite. Aluminum gel is an intermediate product of cement hydration, existing in the form of amorphous Al(OH)3 or low-crystallinity hydrated alumina (Al2O3﹒nH2O), with high reactivity. Further, aluminum gel and dicalcium silicate generate hydrated calcium aluminosilicate, while promoting the conversion of calcium sulfoaluminate into monosulfide hydrated calcium sulfoaluminate. Hydrated calcium aluminosilicate has a layered structure, which can fill pores and improve density, significantly improving the early and late strength of Belite sulfoaluminate cement.

[0035] from Figure 8 It can be seen that a large amount of ettringite is generated in the slurry of the belite sulfoaluminate cement prepared in Comparative Example 1. Unreacted gypsum is still present after 90 days of hydration, and no diffraction peaks of calcium hydroxide and hydrated calcium aluminosilicate (Stratlingite) are observed, indicating that the high gypsum content hinders the later hydration of belite.

[0036] Test Example 2 In this test example, the belite sulphoaluminate cement products prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to cement paste strength tests. The water-cement ratio of the belite sulphoaluminate cement paste was 0.4, and the curing condition was water curing at 20°C. The test results of the belite sulphoaluminate cement paste strength were as follows: Figure 9As shown in the figure, it can be seen that the early strength of the belite sulphoaluminate cement paste prepared in Examples 1 to 3 develops rapidly. As the hydration age increases, the later strength of the belite sulphoaluminate cement paste does not shrink, showing a stable growth trend. The hydration of dicalcium silicate promotes the growth of the later strength of the belite sulphoaluminate cement paste. In the belite sulphoaluminate cement prepared in Comparative Example 1, the early strength of the belite sulphoaluminate cement paste increases with the increase in the amount of raw gypsum, but the later strength increases slowly, indicating that a larger amount of raw gypsum is not conducive to the hydration activity of dicalcium silicate, which corresponds to the results of Test Example 1. Compared with the belite sulphoaluminate cement prepared in Comparative Example 2, the cement paste of Example 1 has higher strength in the early, middle, and late stages, indicating that the increase in calcination temperature is not conducive to the hydration activity of calcium sulphoaluminate.

[0037] Test Example 3 In this test example, the cement products obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to chemically bound water content analysis of cement paste. The relationship between the chemically bound water content and the strength of the belite sulphoaluminate cement paste is shown in the following figure: Figure 10 As shown in the figure, it can be seen that the compressive strength of the belite sulphoaluminate cement paste is closely related to the chemically bound water content. As the chemically bound water content decreases, the compressive strength also decreases. The chemically bound water content of the cement paste in Example 1 is higher than that in Comparative Examples 1 and 2, indicating that under the condition of low-temperature calcination, a relatively small amount of raw gypsum is beneficial to promote the hydration of dicalcium silicate, thereby improving the later strength of the belite sulphoaluminate cement.

[0038] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. 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, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A low-temperature preparation method of Belite sulphoaluminate cement, characterized in that: The steps include: S1. Preparation of cement clinker: The raw materials of the Belite sulphoaluminate cement clinker were ground to obtain cement raw material; the raw materials were mixed, pressed and dried to obtain a raw cake, which was calcined and cooled to room temperature to obtain Belite sulphoaluminate cement clinker; S2. Preparation of Belite Sulphoaluminate Cement: The cement clinker is mixed with raw gypsum and ground to obtain Belite Sulphoaluminate Cement.

2. The low-temperature preparation method according to claim 1, characterized in that: The mass ratio of the belite sulphoaluminate cement clinker in step S1 to the raw gypsum in step S2 is (93-100):(0.5-7).

3. The low-temperature preparation method according to claim 2, characterized in that: The raw materials of the belite sulphoaluminate cement clinker in step S1 include, by mass, 82-96 parts of limestone, 6-17 parts of gypsum, 5-28 parts of bauxite, 18-42 parts of fly ash, and 0-0.5 parts of calcium fluoride.

4. The low-temperature preparation method according to claim 3, characterized in that: The content of Al2O3 in the bauxite is 55-70wt.%.

5. The low-temperature preparation method according to claim 1, characterized in that: The mineral phase of the belite sulphoaluminate cement clinker in step S1 includes the following components in parts by mass: 45-70 parts of dicalcium silicate, 25-40 parts of calcium sulphoaluminate, 2-10 parts of tetracalcium aluminoferrite, 0-5 parts of calcium sulphosilicate, and 0-5 parts of high-temperature anhydrite.

6. The low-temperature preparation method according to claim 5, characterized in that: The raw materials of the belite sulphoaluminate cement clinker in step S1 are ground and then passed through a 100-200 mesh sieve.

7. The low-temperature preparation method according to claim 6, characterized in that: The calcination temperature in step S1 is 1120-1200° C., and the holding time is 20-60 minutes.

8. The low-temperature preparation method according to claim 7, characterized in that: In step S2, the cement clinker and gypsum are mixed, ground, and then passed through a 100-200 mesh sieve.

9. The low-temperature preparation method according to any one of claims 1 to 8, characterized in that: The specific surface area of ​​the Belite sulphoaluminate cement in step S2 is 320-380m 2 / kg.

10. Belite sulphoaluminate cement prepared by the low-temperature preparation method according to any one of claims 1 to 9.

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