Sulfate silicate cement, its preparation process and its applications
The sulfo-silicate cement addresses the balance of strength and expansion performance issues in existing cements by using a simple process with specific clinker components, ensuring long-term structural integrity.
Patent Information
- Application Number
- FR2025000102
- Authority / Receiving Office
- FR · FR
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-09-04
- Filing Date
- 2025-01-07
- Publication Date
- 2026-03-06
AI Technical Summary
Existing cements face challenges in achieving a balance between excellent initial and advanced phase strength and expansion performance, require high-quality raw materials that are difficult to obtain, and involve complex preparation processes with high costs and energy consumption.
A sulfo-silicate cement comprising specific proportions of C5S2$, C2S, C4A3$, C4AF, and fC$ in the sulfo-silicate cement clinker, combined with gypsum, is prepared using a simple process that utilizes abundant raw materials and reduces energy consumption.
The sulfo-silicate cement achieves excellent initial and advanced phase strengths with controlled expansion performance, suitable for various construction applications and maintains long-term integrity.
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Abstract
Description
Title of the invention: Sulfate silicate cement, its preparation process and its applications technical field
[0001] This application relates to the field of construction cement, and in particular sulfosilicate cement, its preparation process and its applications. PRIOR TECHNOLOGY
[0002] With advances in technology, the building industry demands higher-performance cementitious materials. Higher-performance cementitious materials are characterized by a low water-to-binder ratio, a high cementitious content, a high active mineral extender content, a low coarse aggregate content, and so on. They exhibit significant shrinkage during hardening and use after hardening, which increases the risk of initial cracking. Cracking of cementitious materials is a significant factor that exacerbates deterioration and even structural failure, reducing the lifespan of buildings. On the other hand, due to the penetration of corrosive ions from outside the cementitious materials, the cracking caused by shrinkage will accelerate the rate of erosion and reduce the lifespan of the structure.It is therefore necessary to develop a cement with the lowest possible shrinkage, or even no shrinkage at all, in order to meet the needs of building engineering.
[0003] In recent years, research on controlling the shrinkage of Portland cement has primarily used magnesium oxide (MgO), calcium oxide (CaO), calcium sulfoaluminate (C4Al3), etc., as expanding agents, adding them to the cement to compensate for the initial shrinkage of Portland cement and reduce the likelihood of cracking in cement-based materials. However, existing expanding agents have complex components, are expensive, and have varying impacts on the performance of Portland cement due to differences between products from different companies, which does not promote quality control of concrete.
[0004] Existing patents disclose a low-heat Portland cement, its preparation process, and its applications. By controlling the dicalcium silicate content to above 40%, the heat of hydration and the drying shrinkage of the cement and its resulting concrete are effectively reduced, which plays a positive role in mitigating the problem of concrete cracking. However, it has a significant drawback of low initial strength.
[0005] In order to solve the problem of low initial strength of Portland cement at low heat, existing patents reveal that by appropriately reducing the dicalcium silicate content (minimum of 35%), the initial strength of Portland cement at low heat can be improved to some extent, but the improvement is limited and cannot meet the requirements.
[0006] Existing patents disclose a process for preparing a high early strength, low shrinkage composite Portland cement using C2OAl13M3S3 (Q-phase) as the initial component and combining it with a low-shrinkage Portland cement clinker with a low tricalcium silicate content. The high early strength is improved to some extent, but it is dependent on the Q-phase of the early strength component. The shrinkage of the admixture or strength-regulating component, such as Q-phase, active MgO, and the like, is difficult to obtain directly in its natural state and must be processed, which increases energy consumption and costs.
[0007] Existing cement fails to find the balance between excellent strength in initial and advanced phases and expansion performance, the problem of a complex preparation process and the high quality requirements of raw materials. Summary of the invention
[0008] Thus, the first technical problem to be solved by the present application is to overcome the defect of existing cements which cannot simultaneously achieve excellent initial and advanced phase strength and expansion performance, so the present application provides a sulfo-silicate cement, its preparation process and its applications.
[0009] The second technical problem that the present application must solve is that existing cement requires high-quality raw materials that are difficult to obtain, and involves high processing costs and complex preparation processes, so the present application provides a sulfo-silicate cement, its preparation process and its applications.
[0010] Consequently, the present application provides the following technical solutions.
[0011] The first aspect of the invention claims a sulfo-silicate cement, in which the sulfo-silicate cement comprises a sulfo-silicate cement clinker and gypsum;
[0012] sulfosilicate cement clinker comprises 3% to 50% of C5S2$, 20% to 70% of C2S, 20% to 45% of C4A3$, 1% to 15% of C4AF, and 0% to 20% of fC$, based on the total mass of sulfosilicate cement clinker; and
[0013] The mass percentage content of gypsum in sulfosilicate cement corresponds to the following calculation formula: C G = 0 / 13 x M x xi00% HAS:
[0014] in which, CG represents the gypsum content in the sulfosilicate cement; Y represents the C4A3$ content in the sulfosilicate cement clinker; Sg represents the SO3 content of the gypsum; M represents the coefficient of gypsum, Me[0-4]; A represents the fC$ content in the sulfosilicate cement clinker; and T represents the C5S2$ content in the sulfosilicate cement clinker.
[0015] In this application, the proportion of each component in sulfosilicate cement clinker is tested by X-ray diffraction. The specific method includes a quantitative analysis following X-ray diffraction testing. In the quantitative XRD analysis, Topas 3 software combined with the Rietveld method is used to analyze the samples with zero-point displacement, background coefficient, scale factor, mesh parameters, and preferred orientation as adjustment parameters; Sg here corresponds to the SO3 content of the gypsum, which is not zero. The SO3 content of different types of gypsum is tested in accordance with GB / T 176-2017, "Chemical analysis methods for cement." The gypsum coefficient (M) is artificially selected according to actual requirements, and the specific selection method depends on the cement expansion performance requirements.The selected M value increases according to the increase in the required rate of cement expansion. When the rate of cement expansion is controlled to reach 0.02% at 28 days, the selected M value is 0.8, and when the rate of cement expansion is controlled to reach 0.06% at 28 days, the selected M value is 3.1.
[0016] According to the present application, the mass ratio of sulfo-silicate cement clinker to gypsum is (60-100): (0-40).
[0017] According to the present application, sulfo-silicate cement clinker is obtained by calcining a mixture of limestone raw material, a silica-alumina raw material, an iron correction material, a sulfur raw material, and an active agent.
[0018] According to the present application, the mass ratio of limestone raw material, silica-alumina raw material, iron correction material, sulfur raw material, and active agent is (35-65): (20-45): (0-30): (2-30): (0.01-2).
[0019] According to the present application, the limestone raw material comprises at least one of the following: limestone, calcium carbide, steel slag, marble, marl, and chalk.
[0020] According to the present application, the silica-alumina raw material comprises at least one element among fly ash, coal gangue, red mud, bauxite, sandstone, clay, shale, and argillite.
[0021] According to the present application, raw materials such as bauxite, fly ash, steel slag, and the like contain an iron oxide component, so it is not necessary to add an iron correction material separately.
[0022] According to the present application, the sulfur raw material comprises at least one element among natural gypsum, phosphogypsum, desulfurized gypsum, and anhydrite.
[0023] According to the present application, the main component of desulfurized gypsum is the same as natural gypsum, which is calcium sulfate dihydrate with a content greater than or equal to 93%. It can be used as a sulfur raw material; natural gypsum is a mineral gypsum found in nature, and its main components are gypsum dihydrate and anhydrite.
[0024] According to the present application, the iron correction material comprises at least one element among iron residues, laterite, pyrite, and iron powder.
[0025] According to the present application, the active agent comprises at least one element from among fluorite, szaibélyite, phosphorus slag, and tourmaline.
[0026] According to this application, calcination is carried out at a temperature between 1200°C and 1300°C for a duration of between 0.5 hours and 2 hours. This application further includes a step of grinding the mixture obtained by mixing before calcination.
[0027] According to the present application, the SO3 content of the gypsum is between 35% and 55%, based on the total mass of the gypsum.
[0028] According to the present application, gypsum comprises at least one element among dihydrated gypsum, hemihydrated gypsum, anhydrite, phosphogypsum, and desulfurized gypsum.
[0029] The second aspect of the invention claims a process for preparing the aforementioned sulfosilicate cement, in which the process comprises: S1, preparing a sulfosilicate cement clinker; and S2, mixing the sulfosilicate cement clinker with gypsum, grinding, and obtaining the sulfosilicate cement.
[0030] According to the present application, sulfo-silicate cement is ground to obtain a specific surface area greater than 300m2 / kg; optionally, sulfo-silicate cement is ground to obtain a specific surface area between 300m2 / kg and 400m2 / kg.
[0031] According to the present application, the quantities of sulfo-silicate cement clinker and gypsum were recorded in the first aspect of this application, and are not repeated here.
[0032] The third aspect of this application claims the use of the aforementioned sulfo-silicate cement or sulfo-silicate cement prepared according to the aforementioned process in the field of building.
[0033] The technical solution of the present application has the following advantages.
[0034] 1. The present application provides a sulfosilicate cement, in which the cement sulfo-silicate comprises sulfo-silicate cement clinker and gypsum; the sulfo-silicate cement clinker comprises 3% to 50% C5S2$, 20% to 70% C2S, 20% to 45% C4A3$, 1% to 15% C4AF, and 0% to 20% fC$, based on the total mass of sulfo-silicate cement clinker; and the quantities of gypsum and sulfo-silicate cement clinker correspond to the following calculation formula: C G = 0.13 XM x X100% : s ; where, CG represents the gypsum content in the sulfosilicate cement; Y represents the C4Al3$ content in the sulfosilicate cement clinker; Sg represents the SO3$ content of the gypsum; M represents the coefficient of gypsum, Me[0-4]; A represents the fC$ content in the sulfosilicate cement clinker; and T represents the C5S2$ content in the sulfosilicate cement clinker. The specific formula in this application can precisely adjust the quantities of sulfosilicate cement clinker and gypsum, so that the sulfosilicate cement has excellent initial and advanced phase strengths as well as expansion performance, which is suitable for various construction scenarios such as casting structural elements, repairing cracks, etc., and allows for long-term integrity after use.
[0035] 2. The present application has low requirements regarding the raw materials of The reaction requires abundant raw material resources and does not necessitate complex raw material pretreatment steps. The preparation process is simple, reducing costs and energy consumption, and is suitable for large-scale applications. BRIEF DESCRIPTION OF THE FIGURES
[0036] In order to provide a clearer explanation of the specific embodiments of this application or of prior art technical solutions, a brief introduction of the figures to be used in the description of the specific embodiments or of the prior art is given below. Of course, the figures described below constitute some embodiments of this application. A person skilled in the art can derive other figures based on these figures without creative effort.
[0037] Fig. 1 represents a photograph of the sulfosilicate cement prepared in Example 1 after 28 days of placement;
[0038] Figure 2 shows a photograph of the sulfosilicate cement prepared in Example 5 after 28 days of placement; and
[0039] Fig. 3 represents a photograph of the sulfosilicate cement prepared in Comparative Example 1 at 28 days of placement. DETAILED DESCRIPTION
[0040] The following examples are provided for the purpose of better understanding this application and are not limited to the embodiments described and do not limit the content and scope of this application. Any product identical or similar to this application and obtained by any person who has been inspired by this application or by combining this application with features of the prior art is covered by the scope of protection of this application.
[0041] When specific experimental steps or conditions are not specified in the examples, the conventional experimental steps or conditions described in the prior art literature may be applied. If the manufacturer of the reagents or instruments used is not specified, they are conventional reagents or instruments that can be acquired on the market.
[0042] Raw material resources are not limited, and come mainly from reused waste.
[0043] The specific numbers and values of the raw materials added and the final products in the examples are whole numbers. Example 1
[0044] This example provides a process for preparing sulfosilicate cement, comprising the following specific steps:
[0045] mix 42 parts limestone, 11 parts calcium carbide slag, 10 parts bauxite, 6 parts sandstone, 5 parts red mud, 25 parts phosphogypsum, and 1 part tourmaline uniformly according to the mass parts, and calcine at 1250°C for 2 hours to obtain sulfo-silicate cement clinker comprising 7% C5S2$, 42% C2S, 39% C4A3$, 5% C4AF, 5% fC$, and the remainder in impurities;
[0046] select desulfurized gypsum (M = 3.0, Sg = 37.59%) for mixing, and
[0047] calculate using the formula, Cr = 0.13 X 3.0 X 3^-^^-7^27 x 100%=20% 37.59% , so that when the quantity of sulfosilicate cement clinker is 80 parts, and the quantity of desulfurized gypsum is 20 parts, mix and grind to obtain a sulfosilicate cement with a specific surface area of 342 m² / kg. The state of the sulfo- silicate after 28 days of placement is shown in [Fig.1], and it can be seen from [Fig.1] that it retains its integrity after 28 days of placement. Example 2
[0048] This example provides a process for preparing sulfosilicate cement, comprising the following specific steps:
[0049] mix 56 parts of limestone, 3 parts of bauxite, 21 parts of fly ash, 1 part of iron residue, 18 parts of anhydrite, and 0.5 parts of fluorite uniformly according to the parts by mass, and calcine at 1250°C for 1.5 hours to obtain sulfo-silicate cement clinker comprising 13% of C5S2$, 35% of C2S, 45% of C4A3$, 5% of C4AF, and 2% of fC$;
[0050] select dihydrated gypsum (M = 3.6, Sg = 35.58%) for mixing, and
[0051] calculate using the formula, _ 3?%, so that when the quantity of 68 parts sulfo-silicate cement clinker, 32 parts dihydrate gypsum, mix and grind to obtain a sulfo-silicate cement with a specific surface area of 356 m2 / kg. Example 3
[0052] This example provides a process for preparing sulfosilicate cement, comprising the following specific steps:
[0053] mix 26 parts of steel slag, 20 parts of marl, 11 parts of shale, 16 parts of coal gangue, 26.2 parts of desulfurized gypsum, 0.3 parts of fluorite, 0.2 parts of szaibelyite, and 0.3 parts of phosphorus slag uniformly according to the mass parts, and calcine at 1260°C for 0.67 hours to obtain sulfo-silicate cement clinker comprising 20% of C5S2$, 46% of C2S, 32% of C4A3$, 2% of C4AF, and no fC$;
[0054] select phosphogypsum (M = 0.9, Sg = 43.10%) for mixing, and
[0055] calculate using the formula, _ 70^, so that when the quantity of clinker sulfo-silicate cement of 98 parts, the quantity of phosphogypsum of 2 parts, mix and grind to obtain a sulfo-silicate cement with a specific surface area of 351 m2 / kg. Example 4
[0056] This example provides a process for preparing sulfosilicate cement, comprising the following specific steps:
[0057] Mix 16 parts steel slag, 35 parts marble, 5 parts clay, 16 parts fly ash, 28.4 parts desulfurized gypsum, 0.2 parts fluorite, and 0.4 parts phosphorus slag uniformly according to the mass proportions, and calcine at 1250°C for 1 hour to obtain sulfo-silicate cement clinker comprising 21% of C5S2$, 34% of C2S, 40% of C4A3$, 3% of C4AF, and 2% of fC$;
[0058] select phosphogypsum (M = 2.7, Sg = 43.10%) for mixing, and
[0059] calculate using the formula, , so that when the quantity of clinker sulfo-silicate cement of 93 parts, the quantity of phosphogypsum of 7 parts, mix and grind to obtain a sulfo-silicate cement with a specific surface area of 349 m2 / kg. Example 5
[0060] This example provides a process for preparing sulfosilicate cement, comprising the following specific steps:
[0061] mix 36 parts of calcium carbide slag, 20 parts of steel slag, 16 parts of sandstone, 9 parts of red mud, 2 parts of laterite, 16.7 parts of phosphogypsum, 0.1 parts of fluorite, and 0.2 parts of szaibélyite uniformly according to the mass parts, and calcine at 1240°C for 1 hour to obtain sulfo-silicate cement clinker comprising 3% of C5S2$, 53% of C2S, 30% of C4A3$, 4% of C4AF, and 10% of fC$;
[0062] do not add gypsum, M = 0, and
[0063] Grind 100 parts of sulfosilicate cement clinker to obtain a sulfosilicate cement with a specific surface area of 353 m² / kg. The state of the sulfosilicate cement after 28 days of placement is shown in [Fig. 2], and it can be seen from example 5 that it retains its integrity. Comparative example 1
[0064] This comparative example provides a process for preparing sulfosilicate cement, comprising the following specific steps:
[0065] A sulfosilicate cement was prepared according to the steps in Example 5; based on mass proportions, 70 parts of sulfosilicate cement clinker and 30 parts of anhydrite were mixed and ground to obtain a sulfosilicate cement with a specific surface area of 361 m² / kg. It can be seen from [Fig. 3] that the sulfosilicate cement prepared in Comparative Example 1 had already broken and disintegrated after 28 days and could not be tested.
[0066] The strength of the prepared cements was tested in accordance with GB / T 17671-2021, and the expansion rate was tested in accordance with JC / T 313-2009. The test results are shown in Table 1.
[0067] [Tables 1] Compressive Strength (MPa) Expansion Rate (%) 3 Days 28 Days 3 Days 28 Days Example 1 37.6 63.7 0.026 0.058 Example 2 33.4 61.8 0.064 0.094 Example 3 31.1 58.8 0.019 0.023 Example 4 35.0 62.6 0.038 0.047 Example 5 30.5 60.3 0.017 0.031 Comparative Example 1 28.2 0.171
[0068] Note: "\" means it is impossible to carry out the test.
[0069] The sulfo-silicate cement produced by this application has excellent initial and advanced phase strengths as well as expansion performance, and can maintain long-term integrity after use.
[0070] Of course, the above examples are merely illustrative and not intended to limit the implementation methods. For ordinary technicians in the field, other forms of change or variation can be made based on the above explanations. It is neither necessary nor possible to list all implementation methods here exhaustively. The obvious changes or variations that result are covered by the scope of protection of this application.
Claims
Demands
1. Sulfosilicate cement, wherein the sulfosilicate cement comprises sulfosilicate cement clinker and gypsum; the sulfosilicate cement clinker comprises 3% to 50% of C5S2$, 20% to 70% of C2S, 20% to 45% of C4A3$, 1% to 15% of C4AF, and 0% to 20% of fC$, based on the total mass of sulfosilicate cement clinker; and the mass percentage content of gypsum in the sulfosilicate cement is calculated using the following formula: Y — _Tv 3 ^7 = 0.13 XMX ----X100% in which, CG represents the gypsum content in the sulfosilicate cement; Y represents the C4A3$ content in the sulfosilicate cement clinker; Sg represents the SO3 content of gypsum; M represents the coefficient of gypsum, Me[0-4]; A represents the fC$ content in sulfosilicate cement clinker; and T represents the C5S2$ content in sulfosilicate cement clinker.
2. Sulfosilicate cement according to claim 1, wherein the mass ratio of sulfosilicate cement clinker to gypsum is (60-100): (0-40).
3. Sulfosilicate cement according to claim 1, wherein the sulfosilicate cement clinker is obtained by calcining a mixture of limestone raw material, silica-alumina raw material, iron correction material, sulfur raw material, and an active agent; optionally, the mass ratio of limestone raw material, silica-alumina raw material, iron correction material, sulfur raw material, and active agent is (35-65): (20-45): (0-30): (2-30): (0.01-2).
4. Sulfosilicate cement according to claim 3, wherein the limestone raw material comprises at least one of the following: limestone, calcium carbide, steel slag, marble, marl, and chalk; and / or the silica-alumina raw material comprises at least one of the following: fly ash, coal gangue, red mud, bauxite, sandstone, clay, shale, and argillite; and / or, the sulfur raw material comprises at least one element from natural gypsum, phosphogypsum, desulfurized gypsum, and anhydrite; and / or, the iron correction material comprises at least one element from iron residues, laterite, pyrite, and iron powder; and / or, the active agent comprises at least one element from fluorite, szaibelyite, phosphorus slag, and tourmaline.
5. Sulfo-silicate cement according to claim 3, wherein calcination is carried out at a temperature between 1200°C and 1300°C for a duration between 0.5 hours and 2 hours.
6. Sulfo-silicate cement according to claim 1, wherein the SO3 content of the gypsum is between 35% and 55%, based on the total mass of the gypsum.
7. Sulfo-silicate cement according to claim 1, wherein the gypsum comprises at least one element among dihydrated gypsum, hemihydrated gypsum, anhydrite, phosphogypsum, and desulfurized gypsum.
8. A process for preparing sulfosilicate cement according to any one of claims 1-7, wherein the process comprises: S1, preparing a sulfosilicate cement clinker; and S2, mixing the sulfosilicate cement clinker with gypsum, grinding, and obtaining the sulfosilicate cement.
9. A process according to claim 8, wherein the sulfo-silicate cement is ground to obtain a specific surface area greater than 300m2 / kg; optionally, the sulfo-silicate cement is ground to obtain a specific surface area between 300m2 / kg and 400m2 / kg.
10. Use of sulfosilicate cement according to any one of claims 1-7 or of sulfosilicate cement prepared using the process according to claim 8 or 9 in the field of building.