A quick-setting and quick-hardening cement clinker, a preparation method and application thereof

Abstract

The application discloses a kind of quick-setting quick-hardening cement clinker and its preparation method and application.The clinker includes calcium sulphosilicate 11.15~22.76wt%, calcium sulphoaluminate 22.21~28.00wt%, dicalcium silicate 39.28~45.72wt%, calcium sulfate 7.93~9.29wt%, iron phase 2.33~3.64wt%, free calcium 0.49~1.52wt%, and the rest is hybrid mineral component;The raw material of the clinker includes limestone 51.0~52.0wt%, phosphogypsum 28.0~30.0wt%, fly ash 9.0~11.0wt%, bauxite 8.0~11.0wt%.The application regulates the proportion and content of each component, and prepares the clinker meeting the requirements while improving the mineral activity, not only early hydration speed is fast, early strength is high, but also ensures that later strength develops stably.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a fast-setting and fast-hardening cement clinker, its preparation method, and its application. Background Technology

[0002] In ordinary silicate cement clinker, the main mineral is allitite (C3S), with a calcium oxide content reaching 73.7% and a formation temperature of approximately 1450℃, resulting in significant energy consumption and high carbon emissions. Belite (C2S), on the other hand, forms rapidly above 1250℃ and has a low calcium oxide content. Therefore, high-belite cement has significant advantages in terms of low energy consumption and low carbon emissions. However, high-belite cement is a low-heat silicate cement with belite as the dominant mineral, exhibiting a slower hydration rate and lower early strength, limiting its application and development. Sulfoaluminate cement, containing a large amount of anhydrous calcium sulfoaluminate (C4A3S), features high early strength and a low firing temperature, but its later strength growth is not significant. Therefore, combining the advantages of both belite cement and sulfoaluminate cement, developing high-belite sulfoaluminate cement with belite and anhydrous calcium sulfoaluminate as the dominant minerals has become a research hotspot. Recent studies have shown that calcium sulfosilicate (C5S2S) exhibits stronger hydration activity than β-C2S in the sulfoaluminate system, and its formation temperature (900-1200℃) is lower than that of β-C2S. Therefore, the main mineral components of Belite sulfoaluminate cement were adjusted from dicalcium silicate and calcium sulfoaluminate to calcium sulfosilicate, dicalcium silicate, and calcium sulfoaluminate, forming dicalcium silicate-calcium sulfoaluminate-calcium sulfosilicate clinker. C5S2S minerals are richer in elements than β-C2S but have a lower calcium content. Therefore, dicalcium silicate-calcium sulfoaluminate-calcium sulfosilicate clinker can reduce the amount of limestone used, improve the utilization rate of solid waste raw materials, effectively reduce the cement firing temperature, and reduce coal consumption. Therefore, the dicalcium silicate-calcium sulfosilicate-calcium sulfoaluminate cement system has a wide range of applications. However, when calcium sulfosilicate and belite coexist in cement clinker and the content of calcium sulfosilicate is higher than that of belite, the dissolution of calcium sulfosilicate during hydration causes silicon ions in the pore solution to reach saturation, which inhibits the hydration of belite and thus affects the later strength development of cement clinker.

[0003] However, when calcium sulfosilicate and belite coexist in cement clinker and the content of calcium sulfosilicate is higher than that of belite, the dissolution of calcium sulfosilicate during hydration causes silicon ions in the pore solution to reach saturation, which inhibits the hydration of belite and thus affects the later strength development of cement clinker. Summary of the Invention

[0004] The purpose of this invention is to provide a rapid-setting and rapid-hardening cement clinker, its preparation method, and its application. The mineral composition of the clinker is optimized to produce a dicalcium silicate-calcium sulfoaluminate-calcium sulfosilicate cement clinker with high early-stage strength, low firing temperature, and stable strength growth in later stages. To achieve the above objective, the technical solution adopted by this invention is as follows:

[0005] A fast-setting and fast-hardening cement clinker comprises the following mineral components by mass fraction: calcium sulfosilicate 11.15–22.76 wt%, calcium sulfoaluminate 22.21–28.00 wt%, dicalcium silicate 39.28–45.72 wt%, calcium sulfate 7.93–9.29 wt%, iron phase 2.33–3.64 wt%, free calcium 0.49–1.52 wt%, with the balance being mixed mineral components;

[0006] The clinker is composed of the following raw materials by mass fraction: limestone 51.0–52.0 wt%, phosphogypsum 28.0–30.0 wt%, fly ash 9.0–11.0 wt%, and bauxite 8.0–11.0 wt%.

[0007] Furthermore, a fast-setting and fast-hardening cement clinker comprises the following mineral composition by mass fraction: 15-20 wt% calcium sulfosilicate, 23-25 ​​wt% calcium sulfoaluminate, 40-42 wt% dicalcium silicate, 8-9 wt% calcium sulfate, 2.5-3.2 wt% iron phase, 0.5-1.2 wt% free calcium, and the balance being mixed mineral components;

[0008] The clinker is composed of the following raw materials by mass fraction: limestone 51.0-52.0 wt%, phosphogypsum 28.0-29.0 wt%, fly ash 9.0-10.0 wt%, and bauxite 8.0-10.0 wt%.

[0009] Further, the mass ratio of dicalcium silicate to calcium sulfosilicate is 1.73 to 3.95:1; the mass ratio of calcium sulfosilicate to calcium sulfoaluminate is 0.4 to 1.02:1; and the iron phase is calcium aluminoferrite.

[0010] Furthermore, the SO3 content in the phosphogypsum is 40-45 wt%.

[0011] Furthermore, the CaO content in the limestone is 50–55 wt%.

[0012] Furthermore, the fly ash contains 50-60 wt% SiO2 and 20-30 wt% Al2O3.

[0013] A method for preparing rapid-setting and fast-hardening cement clinker includes the following steps:

[0014] Step 1: Dry the raw materials limestone, phosphogypsum, fly ash and bauxite, then crush and grind them into the corresponding raw material powders for later use.

[0015] Step 2: Mix and grind the raw material powders obtained in Step 1 according to their mass fractions to obtain cement raw meal;

[0016] Step 3: After mixing the cement raw meal with water, press it into corrugated test cakes and dry them in an oven; preferably, the mass of water added is 10-12 wt% of the mass of the cement raw meal, the size of the corrugated test cake is 13 mm × 10 mm, and the oven temperature is 105 ℃.

[0017] Step 4: Place the dried corrugated test cake in a high-temperature furnace for calcination. After calcination, quickly remove the corrugated test cake and cool it to room temperature to obtain the cement clinker. Preferably, the cooling is achieved by fan quenching.

[0018] Furthermore, the fineness of the cement raw meal meets the requirement that the residue on an 80μm sieve is less than 12%.

[0019] Further, in step 4, the temperature is increased to 900°C at a heating rate of 10-20°C / min, the corrugated test cake is kept at 900°C for 20 min, and then increased to 1210-1250°C at a heating rate of 5-10°C / min, the corrugated test cake is kept at 1210-1250°C for 30-60 min.

[0020] The present invention discloses the application of the above-mentioned rapid-setting and rapid-hardening cement clinker in cement preparation.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention uses calcium sulfosilicate to replace a small portion of dicalcium silicate (belite). The presence of calcium sulfosilicate is beneficial to the development of the later-stage strength of cement clinker. A small amount of calcium sulfosilicate ensures the full utilization of the hydration activity of belite, preventing the dissolution of large amounts of calcium sulfosilicate during hydration from saturating silicon ions in the pore solution and inhibiting belite hydration, thus guaranteeing the later-stage strength development of cement clinker. Furthermore, the calcined cement clinker also contains highly active α-C2S (α-dicalcium silicate), whose hydration activity is higher than that of β-C2S (β-dicalcium silicate), which, together with calcium sulfosilicate, can provide a guarantee for the later-stage strength development of clinker.

[0023] 2. The calcination temperature of the cement clinker of the present invention is 1210-1250℃, which is about 200-250℃ lower than the process temperature of ordinary silicate cement (OPC) and about 50-150℃ lower than the process temperature of sulfoaluminate cement (CSA). This can effectively reduce production energy consumption, and the CO2 emissions during the clinker preparation process are low, showing significant low-carbon advantages.

[0024] 3. The cement clinker of this invention contains a small amount of free calcium (f-CaO). f-CaO promotes the hydration of anhydrous calcium sulfoaluminate in the early stage of cement hydration, thus accelerating early setting and hardening. Although the f-CaO content of this invention exceeds the maximum limit of 0.2 wt% for f-CaO in ordinary sulfoaluminate cement clinker, the calcium sulfoaluminate content in the cement clinker of this invention is only 22.21–28.00 wt%, far lower than the 60–70 wt% content of anhydrous calcium sulfoaluminate minerals in ordinary sulfoaluminate cement clinker.

[0025] 4. The cement clinker of the present invention contains a certain amount of calcium sulfate (CaSO4). CaSO4 reacts with calcium sulfoaluminate to form ettringite, which can promote the early strength development of cement clinker. Attached Figure Description

[0026] Figure 1 The image shows the XRD pattern of the cement clinker prepared in Example 1.

[0027] Figure 2 The image shows the XRD pattern of the cement clinker prepared in Example 2.

[0028] Figure 3 The image shows the XRD pattern of the cement clinker prepared in Example 3.

[0029] Figure 4 The image shows the XRD pattern of the cement clinker prepared in Example 4.

[0030] Figure 5 The image shows the XRD pattern of the cement clinker prepared in Example 5.

[0031] Figure 6 The XRD pattern of the cement clinker prepared in Comparative Example 1 is shown.

[0032] Figure 7 The image shows the XRD pattern of the cement clinker from Comparative Example 2. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0034] Example 1

[0035] As a preferred embodiment of the present invention, the fast-setting and fast-hardening cement clinker disclosed in this embodiment is composed of the following raw materials by mass fraction: limestone 52.0 wt%, phosphogypsum 28.0 wt%, fly ash 10.0 wt%, and bauxite 10.0 wt%.

[0036] This embodiment of a method for preparing fast-setting and fast-hardening cement clinker includes the following steps:

[0037] Step 1: Dry the raw materials limestone, phosphogypsum, fly ash and bauxite, then crush and grind them into the corresponding raw material powders for later use.

[0038] Step 2: Mix and grind the raw material powders obtained in Step 1 according to the above mass ratio to obtain cement raw meal. The fineness of the cement raw meal meets the requirement that the residue on an 80μm sieve is less than 12%.

[0039] Step 3: After mixing the cement raw materials with water, press them into corrugated test cakes and dry them in an oven. The water added is 10wt% of the cement raw materials. The size of the corrugated test cakes is 13mm×10mm. The oven temperature is 105℃.

[0040] Step 4: Place the dried corrugated test cake in a high-temperature furnace for calcination. After calcination, quickly remove the corrugated test cake and cool it to room temperature with a fan to obtain the cement clinker. The calcination process involves heating the temperature to 900°C at a rate of 10-20°C / min, holding the corrugated test cake at 900°C for 20 minutes, and then heating the temperature to 1230°C at a rate of 5-10°C / min. The corrugated test cake is then held at 1230°C for 40 minutes.

[0041] According to Rietveld quantitative analysis, the mineral composition of the cement clinker in this embodiment is as follows: calcium sulfosilicate 12.33 wt%, calcium sulfoaluminate 25.25 wt%, dicalcium silicate 45.72 wt%, calcium sulfate 8.01 wt%, calcium aluminoferrite 3.34 wt%, free calcium 0.97 wt%, and the balance being mixed mineral components.

[0042] In this embodiment, 10 wt% of anhydrite is added to the cement clinker, and then the mixture is ground to a specific surface area of ​​447 m². 2 / kg, made into cement.

[0043] Example 2

[0044] As a preferred embodiment of the present invention, the fast-setting and fast-hardening cement clinker disclosed in this embodiment is composed of the following raw materials by mass fraction: limestone 51.5 wt%, phosphogypsum 29.0 wt%, fly ash 10.5 wt%, and bauxite 9.0 wt%.

[0045] This embodiment of a method for preparing fast-setting and fast-hardening cement clinker includes the following steps:

[0046] Step 1: Dry the raw materials limestone, phosphogypsum, fly ash and bauxite, then crush and grind them into the corresponding raw material powders for later use.

[0047] Step 2: Mix and grind the raw material powders obtained in Step 1 according to the above mass ratio to obtain cement raw meal. The fineness of the cement raw meal meets the requirement that the residue on an 80μm sieve is less than 12%.

[0048] Step 3: After mixing the cement raw materials with water, press them into corrugated test cakes and dry them in an oven. The water added is 10wt% of the cement raw materials. The size of the corrugated test cakes is 13mm×10mm. The oven temperature is 105℃.

[0049] Step 4: Place the dried corrugated test cake in a high-temperature furnace for calcination. After calcination, quickly remove the corrugated test cake and cool it to room temperature with a fan to obtain the cement clinker. The calcination process involves heating the temperature to 900°C at a rate of 10-20°C / min, holding the corrugated test cake at 900°C for 20 minutes, and then heating the temperature to 1210°C at a rate of 5-10°C / min. The corrugated test cake is then held at 1210°C for 60 minutes.

[0050] According to Rietveld quantitative analysis, the mineral composition of the cement clinker in this embodiment is as follows: calcium sulfosilicate 15.90 wt%, calcium sulfoaluminate 23.96 wt%, dicalcium silicate 43.53 wt%, calcium sulfate 8.15 wt%, calcium aluminoferrite 3.64 wt%, free calcium 0.84 wt%, and the balance being mixed mineral components.

[0051] In this embodiment, 10 wt% of anhydrite is added to the cement clinker, and then the mixture is ground to a specific surface area of ​​452 m². 2 / kg, made into cement.

[0052] Example 3

[0053] As a preferred embodiment of the present invention, the fast-setting and fast-hardening cement clinker disclosed in this embodiment is composed of the following raw materials by mass fraction: limestone 52.0 wt%, phosphogypsum 28.0 wt%, fly ash 9.0 wt%, and bauxite 11.0 wt%.

[0054] This embodiment of a method for preparing fast-setting and fast-hardening cement clinker includes the following steps:

[0055] Step 1: Dry the raw materials limestone, phosphogypsum, fly ash and bauxite, then crush and grind them into the corresponding raw material powders for later use.

[0056] Step 2: Mix and grind the raw material powders obtained in Step 1 according to the above mass ratio to obtain cement raw meal. The fineness of the cement raw meal meets the requirement that the residue on an 80μm sieve is less than 12%.

[0057] Step 3: After mixing the cement raw materials with water, press them into corrugated test cakes and dry them in an oven. The water added is 10wt% of the cement raw materials. The size of the corrugated test cakes is 13mm×10mm. The oven temperature is 105℃.

[0058] Step 4: Place the dried corrugated test cake in a high-temperature furnace for calcination. After calcination, quickly remove the corrugated test cake and cool it to room temperature with a fan to obtain the cement clinker. The calcination process involves heating the temperature to 900°C at a rate of 10-20°C / min, holding the corrugated test cake at 900°C for 20 minutes, and then heating the temperature to 1250°C at a rate of 5-10°C / min. The corrugated test cake is then held at 1250°C for 40 minutes.

[0059] According to Rietveld quantitative analysis, the mineral composition of the cement clinker in this embodiment is as follows: calcium sulfosilicate 12.13 wt%, calcium sulfoaluminate 28.00 wt%, dicalcium silicate 44.02 wt%, calcium sulfate 9.29 wt%, calcium aluminoferrite 2.33 wt%, free calcium 0.49 wt%, and the balance being mixed mineral components.

[0060] In this embodiment, 5 wt% of anhydrite was added to the cement clinker, and then the mixture was ground to a specific surface area of ​​443 m². 2 / kg, made into cement.

[0061] Example 4

[0062] As a preferred embodiment of the present invention, the fast-setting and fast-hardening cement clinker disclosed in this embodiment is composed of the following raw materials by mass fraction: limestone 52.0 wt%, phosphogypsum 28.0 wt%, fly ash 9.0 wt%, and bauxite 11.0 wt%.

[0063] This embodiment describes a method for preparing fast-setting and fast-hardening cement clinker, comprising the following steps:

[0064] Step 1: Dry the raw materials limestone, phosphogypsum, fly ash and bauxite, then crush and grind them into the corresponding raw material powders for later use.

[0065] Step 2: Mix and grind the raw material powders obtained in Step 1 according to the above mass ratio to obtain cement raw meal. The fineness of the cement raw meal meets the requirement that the residue on an 80μm sieve is less than 12%.

[0066] Step 3: After mixing the cement raw materials with water, press them into corrugated test cakes and dry them in an oven. The water added is 10wt% of the cement raw materials. The size of the corrugated test cakes is 13mm×10mm. The oven temperature is 105℃.

[0067] Step 4: Place the dried corrugated test cake in a high-temperature furnace for calcination. After calcination, quickly remove the corrugated test cake and cool it to room temperature with a fan to obtain the cement clinker. The calcination process involves heating the temperature to 900°C at a rate of 10-20°C / min, holding the corrugated test cake at 900°C for 20 minutes, and then heating the temperature to 1230°C at a rate of 5-10°C / min. The corrugated test cake is then held at 1230°C for 40 minutes.

[0068] According to Rietveld quantitative analysis, the mineral composition of the cement clinker in this embodiment is as follows: calcium sulfosilicate 11.15wt%, calcium sulfoaluminate 27.93wt%, dicalcium silicate 44.02wt%, calcium sulfate 8.12wt%, calcium aluminoferrite 2.99wt%, free calcium 1.52wt%, and the balance being mixed mineral components.

[0069] In this embodiment, 10 wt% of anhydrite is added to the cement clinker, and then the mixture is ground to a specific surface area of ​​449 m². 2 / kg, made into cement.

[0070] Example 5

[0071] As a preferred embodiment of the present invention, the fast-setting and fast-hardening cement clinker disclosed in this embodiment is composed of the following raw materials by mass fraction: limestone 51.0 wt%, phosphogypsum 30.0 wt%, fly ash 11.0 wt%, and bauxite 8.0 wt%.

[0072] This embodiment describes a method for preparing fast-setting and fast-hardening cement clinker, comprising the following steps:

[0073] Step 1: Dry the raw materials limestone, phosphogypsum, fly ash and bauxite, then crush and grind them into the corresponding raw material powders for later use.

[0074] Step 2: Mix and grind the raw material powders obtained in Step 1 according to the above mass ratio to obtain cement raw meal. The fineness of the cement raw meal meets the requirement that the residue on an 80μm sieve is less than 12%.

[0075] Step 3: After mixing the cement raw materials with water, press them into corrugated test cakes and dry them in an oven. The water added is 10wt% of the cement raw materials. The size of the corrugated test cakes is 13mm×10mm. The oven temperature is 105℃.

[0076] Step 4: Place the dried corrugated test cake in a high-temperature furnace for calcination. After calcination, quickly remove the corrugated test cake and cool it to room temperature with a fan to obtain the cement clinker. The calcination process involves heating the temperature to 900°C at a rate of 10-20°C / min, holding the corrugated test cake at 900°C for 20 minutes, and then heating the temperature to 1220°C at a rate of 5-10°C / min. The corrugated test cake is then held at 1220°C for 40 minutes.

[0077] According to Rietveld quantitative analysis, the mineral composition of the cement clinker in this embodiment is as follows: calcium sulfosilicate 22.76 wt%, calcium sulfoaluminate 22.21 wt%, dicalcium silicate 39.28 wt%, calcium sulfate 7.93 wt%, calcium aluminoferrite 3.13 wt%, free calcium 1.16 wt%, and the balance being mixed mineral components.

[0078] In this example, 10 wt% of anhydrite was added to the cement clinker, and then the mixture was ground to a specific surface area of ​​459 m². 2 / kg, made into cement.

[0079] Comparative Example 1

[0080] The cement clinker in this comparative example is composed of the following raw materials by mass fraction: limestone 49.0 wt%, phosphogypsum 21.0 wt%, fly ash 9.0 wt%, and bauxite 21.0 wt%.

[0081] The method for preparing cement clinker in this comparative example includes the following steps:

[0082] Step 1: Dry the raw materials limestone, phosphogypsum, fly ash and bauxite, then crush and grind them into the corresponding raw material powders for later use.

[0083] Step 2: Mix and grind the raw material powders obtained in Step 1 according to the above mass ratio to obtain cement raw meal. The fineness of the cement raw meal meets the requirement that the residue on an 80μm sieve is less than 12%.

[0084] Step 3: After mixing the cement raw materials with water, press them into corrugated test cakes and dry them in an oven. The water added is 10wt% of the cement raw materials. The size of the corrugated test cakes is 13mm×10mm. The oven temperature is 105℃.

[0085] Step 4: Place the dried corrugated test cake in a high-temperature furnace for calcination. After calcination, quickly remove the corrugated test cake and cool it to room temperature with a fan to obtain cement clinker. The calcination process involves heating the temperature to 900℃ at a rate of 10-20℃ / min, holding the corrugated test cake at 900℃ for 20 minutes, and then heating it to 1200℃ at a rate of 5-10℃ / min. The corrugated test cake is then held at 1200℃ for 60 minutes.

[0086] According to Rietveld quantitative analysis, the mineral composition of the cement clinker in this comparative example is as follows: calcium sulfosilicate 28.56 wt%, calcium sulfoaluminate 41.94 wt%, dicalcium silicate 18.75 wt%, calcium sulfate 1.66 wt%, calcium aluminoferrite 3.16 wt%, free calcium 0.01 wt%, and the balance being mixed mineral components.

[0087] In this comparative example, 10 wt% of anhydrite was added to the cement clinker, and then the mixture was ground to a specific surface area of ​​437 m². 2 / kg, made into cement.

[0088] Comparative Example 2

[0089] This comparative example is a high-belite sulfoaluminate cement clinker produced by a certain unit, with a firing temperature range of 1350±25℃. Rietveld quantitative analysis revealed the following mineral composition of the cement clinker: tricalcium aluminate (C3Amonoclinic) 3.06 wt%, calcium sulfoaluminate 41.73 wt%, dicalcium silicate 41.92 wt%, calcium sulfate 2.53 wt%, free calcium 0.12 wt%, and the remainder being mixed mineral components.

[0090] In this comparative example, 15 wt% of anhydrite was added to the cement clinker, and then the mixture was ground to a specific surface area of ​​352 m². 2 / kg, made into cement.

[0091] The mechanical properties of cement in Examples 1 to 5 and Comparative Examples 1 to 5 were tested according to GB 20472-2006 "Sulphoaluminate Cement". The water content was determined by a water-cement ratio of 0.47 (211.5 mL) and a mortar flowability of 165 mm to 175 mm. The mechanical properties are shown in Table 1.

[0092] Table 1. Test results of mechanical properties of various cements

[0093]

[0094] According to the data in Table 1, the 28-day flexural strength of the cement prepared in the embodiments of the present invention meets the 28-day flexural strength requirement of the national standard GB175-2007 for general-purpose cement. The 28-day compressive strength of the cement prepared in the embodiments of the present invention also meets the 28-day compressive strength requirement of the national standard GB175-2007 for general-purpose cement. Furthermore, the 28-day compressive strength of the cement in Examples 1, 2, and 3 is significantly greater than that of the cement in Comparative Example 2. The calcium sulfosilicate content in the cement clinker of Comparative Example 1 is much higher than that of dicalcium silicate, which inhibits belite hydration and thus affects the later-stage strength development of the cement clinker. Therefore, the 28-day compressive strength of the cement in Comparative Example 1 is lower than that of the other examples.

[0095] Figures 1-5 The images are XRD patterns of the cement clinker prepared in Examples 1 through 5, respectively. Figures 6-7The XRD patterns of cement clinker from Comparative Examples 1 and 2 are shown below. The XRD patterns of cement clinker prepared in Examples 1-5 by changing the batching scheme and calcination temperature show the following mineral composition ranges: calcium sulfosilicate (Temesite) 11.15–22.76 wt%, calcium sulfoaluminate (Ca4Al6O3) wt%. 12 The cement clinker contained 22.21–28.00 wt% SO4, 39.28–45.72 wt% dicalcium silicate (shown as all C2S markings), 7.93–9.29 wt% anhydrite, 2.33–3.64 wt% C4AF Colville, and 0.49–1.52 wt% free calcium. The calcium sulfosilicate content was lower than the dicalcium silicate content, and the clinker contained a certain amount of calcium sulfate and free calcium. The XRD pattern of the cement clinker in Comparative Example 1 showed the same mineral composition as Examples 1–5, but the calcium sulfosilicate (28.56 wt%) content was higher than the dicalcium silicate (18.75 wt%) content, while the calcium sulfate and free calcium contents were lower. The XRD pattern of the cement clinker in Comparative Example 2 showed that the main minerals were calcium sulfoaluminate and dicalcium silicate, with low calcium sulfate and free calcium contents.

[0096] Finally, it should be noted that the above embodiments are merely preferred embodiments of the present invention used to illustrate the technical solutions of the present invention, and are not intended to limit the invention, nor are they intended to limit the patent scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. That is to say, any changes or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but whose technical problems are still consistent with the present invention, should be included within the protection scope of the present invention. In addition, the direct or indirect application of the technical solutions of the present invention to other related technical fields are similarly included within the patent protection scope of the present invention.

Claims

1. A fast-setting and fast-hardening cement clinker, characterized in that, The mineral composition, expressed by mass fraction, includes: calcium sulfosilicate 11.15–22.76 wt%, calcium sulfoaluminate 22.21–28.00 wt%, dicalcium silicate 39.28–45.72 wt%, calcium sulfate 7.93–9.29 wt%, iron phase 2.33–3.64 wt%, free calcium 0.49–1.52 wt%, with the balance being mixed mineral components. The clinker is composed of the following raw materials by mass fraction: limestone 51.0-52.0 wt%, phosphogypsum 28.0-30.0 wt%, fly ash 9.0-11.0 wt%, and bauxite 8.0-11.0 wt%.

2. The rapid-setting and rapid-hardening cement clinker according to claim 1, characterized in that, The mineral composition includes the following by mass fraction: calcium sulfosilicate 15-20 wt%, calcium sulfoaluminate 23-25 ​​wt%, dicalcium silicate 40-42 wt%, calcium sulfate 8-9 wt%, iron phase 2.5-3.2 wt%, free calcium 0.5-1.2 wt%, and the balance being mixed mineral components. The clinker is composed of the following raw materials by mass fraction: limestone 51.0-52.0 wt%, phosphogypsum 28.0-29.0 wt%, fly ash 9.0-10.0 wt%, and bauxite 8.0-10.0 wt%, with the sum of the mass fractions of the raw materials being 100%.

3. The rapid-setting and rapid-hardening cement clinker according to claim 1, characterized in that, The mass ratio of dicalcium silicate to calcium sulfosilicate is 1.73~3.95:1; the mass ratio of calcium sulfosilicate to calcium sulfoaluminate is 0.4~1.02:1; and the iron phase is calcium aluminoferrite.

4. The rapid-setting and rapid-hardening cement clinker according to claim 1, characterized in that, The SO3 content in the phosphogypsum is 40-45 wt%.

5. The rapid-setting and rapid-hardening cement clinker according to claim 1, characterized in that, The limestone contains 50-55 wt% CaO.

6. The rapid-setting and rapid-hardening cement clinker according to claim 1, characterized in that, The fly ash contains 50-60 wt% SiO2 and 20-30 wt% Al2O3.

7. A method for preparing rapid-setting and rapid-hardening cement clinker according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Dry the raw materials limestone, phosphogypsum, fly ash and bauxite, then crush and grind them into the corresponding raw material powders for later use. Step 2: Mix and grind the raw material powders obtained in Step 1 according to their mass fractions to obtain cement raw meal; Step 3: Add water to the cement raw materials, mix well, press into corrugated test cakes, and dry in an oven; Step 4: Place the dried corrugated test cake in a high-temperature furnace for calcination. After calcination, quickly remove the corrugated test cake and cool it to room temperature to obtain the cement clinker.

8. The method for preparing a rapid-setting and rapid-hardening cement clinker according to claim 7, characterized in that, In step 3, the water added is 10-12 wt% of the cement raw material, the corrugated test cake size is 13 mm × 10 mm, and the oven temperature is 105 ℃.

9. The method for preparing a rapid-setting and rapid-hardening cement clinker according to claim 7, characterized in that, In step 4, cooling is achieved using a fan-assisted rapid cooling method.

10. A method for preparing rapid-setting and rapid-hardening cement clinker according to claim 7, characterized in that, The fineness of the cement raw meal meets the requirement that the residue on an 80 μm sieve is less than 12%.

11. The method for preparing a rapid-setting and rapid-hardening cement clinker according to claim 7, characterized in that, In step 4, the temperature is increased to 900℃ at a heating rate of 10~20℃ / min, and the corrugated test cake is kept at 900℃ for 20min. Then, the temperature is increased to 1210~1250℃ at a heating rate of 5-10℃ / min, and the corrugated test cake is kept at 1210~1250℃ for 30~60min.

12. The application of a fast-setting and fast-hardening cement clinker according to any one of claims 1 to 6 in the preparation of cement.

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