A method for producing silicate cement clinker using high-content crystalline SiO2 silica raw materials

Abstract

This invention discloses a method for producing silicate cement clinker using high-content crystalline SiO2 silicate raw materials. A chemical activator is incorporated into the high-content crystalline SiO2 silicate raw materials during grinding to enhance the reactivity of the crystalline silicon. This raw material is then used to formulate silicate cement raw meal, which is subsequently calcined to obtain silicate cement clinker. The clinker produced using this method exhibits high early strength and high later-stage strength, with the early and later-stage strengths developing in a balanced manner. Cement mortar prepared from this clinker achieves strengths exceeding 30 MPa, 45 MPa, and 60 MPa at 3 days, 7 days, and 28 days, respectively, demonstrating a significant improvement in the mechanical properties of the clinker.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering materials technology, specifically relating to a method for producing silicate cement clinker using high-content crystalline SiO2 silica raw materials. Background Technology

[0002] Silicate cement clinker is mainly composed of tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), and tetracalcium aluminoferrite (C4AF). SiO2 is one of the main oxide components in silicate cement clinker, and its crystallization characteristics in the raw materials have a decisive influence on the energy consumption of silicate cement clinker firing and the quality of clinker.

[0003] Currently, due to the scarcity of natural resources, the siliceous raw materials used in the production of silicate cement clinker all contain a large amount of crystalline SiO2. Because crystalline SiO2 has low reactivity, this inevitably leads to increased energy consumption during silicate cement clinker firing and a decrease in clinker quality. Therefore, developing a method to improve the performance of silicate cement clinker prepared from siliceous raw materials with high crystalline SiO2 content is of significant guiding importance for the sustainable development of cement enterprises. Summary of the Invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a method for producing silicate cement clinker using low-grade materials containing a large amount of crystalline SiO2, thereby improving the performance of silicate cement clinker and reducing its production cost.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for producing silicate cement clinker using high-content crystalline SiO2 silicate raw materials involves adding a chemical activator to the high-content crystalline SiO2 silicate raw materials and grinding them to improve the reactivity of the crystalline silicon in the silicate raw materials. Then, the raw materials are used as raw materials to prepare silicate cement raw meal, which is then calcined to obtain silicate cement clinker.

[0007] Specifically, the method of the present invention includes the following steps:

[0008] (1) Raw material grinding: Limestone, bauxite and non-ferrous metal slag are ground to less than 10% residue on an 80μm sieve. High-content crystalline SiO2 silica raw materials are crushed and then mixed with chemical activators and ground for 10-30 minutes.

[0009] (2) Raw meal preparation: Prepare silicate cement raw meal according to the dry basis raw material mass percentage;

[0010] (3) Clinker calcination: The cement raw meal from step (2) is heated to 850-950℃ at a rate of 10-20℃ / min and held for 20-40 minutes, and then heated to 1400-1500℃ and held for 20-40 minutes.

[0011] (4) Clinker cooling: The clinker obtained from calcination in step (3) is rapidly cooled to room temperature to obtain blocky silicate cement clinker;

[0012] (5) Clinker grinding: Grind the blocky silicate cement clinker obtained in step (4) to a specific surface area of ​​340-360 m2 / kg.

[0013] Preferably, the high-content crystalline SiO2 raw material is sandstone; wherein the content of crystalline SiO2 is ≥60wt / %.

[0014] Preferably, the chemical activator is selected from any one of triethanolamine (TEA), triisopropanolamine (TIPA), diethanolamine monoisopropanolamine (DEIPA), and monoethanolamine diisopropanolamine (EDIPA).

[0015] In existing reports, triethanolamine (TEA), triisopropanolamine (TIPA), diethanolamine monoisopropanolamine (DEIPA), and monoethanolamine diisopropanolamine (EDIPA) are commonly used as grinding aids for cement clinker. This invention is the first to discover that using the above-mentioned chemical activators when grinding raw materials with high crystalline SiO2 content can stimulate the reactivity of crystalline SiO2 in the raw materials, thereby improving the strength of silicate cement clinker.

[0016] Preferably, the chemical activator dosage is 0.02% to 0.1% of the mass of the high-content crystalline SiO2 raw material.

[0017] Preferably, in step (2), the silicate cement raw material is made from the following raw materials in the following mass percentages: 10% to 20% high-content crystalline SiO2 silica raw material, 1.5% to 5.0% bauxite, 1.5% to 3.0% non-ferrous metal slag, and the balance being limestone.

[0018] Preferably, the ratio of the silicate cement clinker is controlled as follows: KH = 0.92 ± 0.02, SM = 2.5 ± 0.1, and IM = 1.5 ± 0.1.

[0019] Furthermore, the silicate cement clinker prepared by the above production method is also within the scope of protection of this invention.

[0020] Furthermore, the silicate cement clinker prepared by the present invention comprises the following mineral composition by mass percentage: tricalcium silicate 56.3%–58.5%, dicalcium silicate 13.1%–17.1%, tricalcium aluminate 4.7%–5.2%, tetracalcium aluminoferrite 8.7%–8.9%, and free calcium oxide 0.5%–1.4%.

[0021] Furthermore, the silicate cement clinker prepared by this invention has cement mortar strengths of 30 MPa, 45 MPa, and 60 MPa or higher at 3 days, 7 days, and 28 days, respectively.

[0022] Beneficial effects:

[0023] (1) This invention is the first to incorporate a chemical activator into high-content crystalline SiO2 silica raw materials for grinding. During the grinding process, the reactivity of crystalline SiO2 in the silica raw materials is activated. The content of free calcium oxide in the clinker prepared by grinding sandstone with a dosage of 0.04% EDIPA for 30 minutes is reduced from 3.81wt / % to 0.5wt / %, which significantly improves the calcination quality of the clinker and realizes that low-grade materials with high content crystalline SiO2 can be used as raw materials for cement production.

[0024] (2) The clinker prepared by the method of the present invention has the characteristics of high early strength and high late strength. The early strength and late strength of the clinker develop in a matching manner. The strength of cement mortar prepared from the clinker reaches more than 30MPa, 45MPa and 60MPa at 3 days, 7 days and 28 days respectively, and the mechanical properties of the clinker are significantly improved. Attached Figure Description

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0026] Figure 1 This invention describes the effect of grinding sandstone for 30 minutes using different chemical activators.

[0027] Figure 2 These are the XRD patterns of silicate cement clinker prepared according to various embodiments and comparative examples of the present invention. Detailed Implementation

[0028] The present invention can be better understood from the following embodiments.

[0029] The chemical composition of the raw materials used in the following examples is shown in Table 1.

[0030] Table 1. Chemical composition of raw materials (wt / %)

[0031]

[0032] Clinker strength testing shall be performed in accordance with the national standard GB / T17671~1999.

[0033] The determination of specific surface area shall be carried out in accordance with the national standard GB / T8074~2008.

[0034] The mineral content in the clinker was obtained by XRD full spectrum fitting, and the calculation was performed using the HighScorePlus software package based on the Rietveld method.

[0035] First, the high-content crystalline SiO2 silica raw material (sandstone) is ground. Figure 1 The images show the D90 values ​​of sandstone after grinding for 30 minutes under different chemical activators and dosages. This invention used four different chemical activators—TEA, TIPA, EDIPA, and DEIPA—to investigate the improvement in the grindability of sandstone at dosages of 0.02%, 0.04%, 0.06%, 0.08%, and 0.1%. It was found that TIPA and EDIPA at all dosages were more effective than TEA and DEIPA in improving the grindability of high-crystalline SiO2 silica raw materials (sandstone). The best grinding effect was observed when using EDIPA at a dosage of 0.08%.

[0036] Example 1

[0037] Sandstone, limestone, bauxite, and non-ferrous metal slag, ground for 30 min with 0.04% EDIPA, were batched according to KH = 0.92 ± 0.02, SM = 2.5 ± 0.1, and IM = 1.5 ± 0.1. The raw materials were batched and mixed uniformly according to the dry basis raw material mass percentage. The complete chemical analysis of the raw materials is shown in Table 1. During the calcination stage, the temperature was increased at 10℃ / min to 900℃, held for 30 min, then increased at 10℃ / min to 1450℃, held for 30 min, and finally rapidly air-cooled to room temperature. The calcined clinker was ground to a specific surface area of ​​340-360 m². 2 The chemical composition of the calcined clinker is shown in Table 2, the mineral composition is shown in Table 3, and the XRD pattern of the cement clinker is shown in Table 4. Figure 2 As shown.

[0038] Example 2

[0039] Sandstone, limestone, bauxite, and non-ferrous metal slag, ground for 10 min with TIPA at a dosage of 0.08%, were batched according to KH = 0.92 ± 0.02, SM = 2.5 ± 0.1, and IM = 1.5 ± 0.1. The raw materials were batched and mixed uniformly according to the dry basis raw material mass percentage. The complete chemical analysis of the raw materials is shown in Table 1. During the calcination stage, the temperature was increased at 10℃ / min to 900℃, held for 30 min, then increased at 10℃ / min to 1450℃, held for 30 min, and finally rapidly cooled to room temperature. The calcined clinker was ground to a specific surface area of ​​340-360 m². 2 The chemical composition of the calcined clinker is shown in Table 2, the mineral composition is shown in Table 3, and the XRD pattern of the cement clinker is shown in Table 4. Figure 2 As shown.

[0040] Comparative Example

[0041] The raw materials, including crushed sandstone that has passed through a 200μm sieve, limestone, bauxite, and non-ferrous metal slag, were batched according to KH = 0.92±0.02, SM = 2.5±0.1, and IM = 1.5±0.1. The raw materials were batched and mixed uniformly according to the dry basis raw material mass percentage. The complete chemical analysis of the raw materials is shown in Table 1. During the calcination stage, the temperature was increased at 10℃ / min to 900℃, held for 30 min, then increased at 10℃ / min to 1450℃, held for 30 min, and finally rapidly cooled to room temperature. The calcined clinker was ground to a specific surface area of ​​340-360 m². 2 The chemical composition of the calcined clinker is shown in Table 2, the mineral composition is shown in Table 3, and the XRD pattern of the cement clinker is shown in Table 4. Figure 2 As shown.

[0042] Table 2. Chemical composition of clinker (wt / %)

[0043]

[0044] Table 3. Clinker mineral content (wt / %)

[0045]

[0046] Table 4 Mortar Strength of Clinker

[0047]

[0048] Table 2 shows the chemical composition of clinker in Examples 1 and 2 and the comparative examples. The chemical composition of the clinker is basically the same, and all belong to the category of ordinary Portland cement. Figure 2Table 3 shows the XRD patterns of Examples 1 and 2 and the comparative example. The table also shows the clinker mineral content obtained quantitatively through XRD full-spectrum fitting. In the comparative example, the f-CaO and C2S contents are significantly higher than in Examples 1 and 2, while the C3S content is lower. This is because the sandstone in the comparative example has a higher content of crystalline SiO2, leading to slower C2S formation and conversion to C3S in the clinker, resulting in a lower C3S content and a higher C2S content.

[0049] This invention provides a method for producing silicate cement clinker using high-content crystalline SiO2 silica raw materials. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for producing silicate cement clinker using high-content crystalline SiO2 silica raw materials, characterized in that, Chemical activators are added to high-content crystalline SiO2 silica raw materials and then milled to improve the reactivity of crystalline silicon in the raw materials. The raw materials are then used as raw materials to prepare silicate cement raw meal, which is then calcined to obtain silicate cement clinker. The high-content crystalline SiO2 silica raw material is sandstone; wherein the content of crystalline SiO2 is ≥60 wt%; The chemical activator is selected from any one of triethanolamine, triisopropanolamine, diethanol monoisopropanolamine, and monoethanolamine diisopropanolamine; The silicate cement raw meal is made from the following raw materials in the indicated mass percentages: 10%–20% high-content crystalline SiO2 silica raw material, 1.5%–5.0% bauxite, 1.5%–3.0% non-ferrous metal slag, and the balance being limestone.

2. The method for producing silicate cement clinker using high-content crystalline SiO2 silica raw materials according to claim 1, characterized in that, Includes the following steps: (1) Raw material grinding: Limestone, bauxite, and non-ferrous metal slag are ground until the residue on an 80μm sieve is less than 10%. High-content crystalline SiO2 silica raw materials are crushed, mixed with chemical activators, and then ground for 10-30 minutes. (2) Raw meal preparation: Prepare silicate cement raw meal by mixing the raw materials from step (1) according to the dry basis raw material mass percentage; (3) Clinker firing: The cement raw meal from step (2) is heated to 850~950℃ at a rate of 10-20℃ / min and held for 20~40min, and then heated to 1400~1500℃ and held for 20~40min. (4) Clinker cooling: The clinker obtained from calcination in step (3) is rapidly cooled to room temperature by air to obtain blocky silicate cement clinker; (5) Clinker grinding: Grind the block silicate cement clinker obtained in step (4) to a specific surface area of ​​340-360 m² / kg.

3. The method for producing silicate cement clinker using high-content crystalline SiO2 silica raw materials according to claim 1, characterized in that, The chemical activator dosage is 0.02% to 0.1% of the mass of the high-content crystalline SiO2 silicon raw material.

4. The method for producing silicate cement clinker using high-content crystalline SiO2 silica raw materials according to claim 1, characterized in that, The ratio values ​​of the silicate cement clinker are controlled as follows: KH=0.92±0.02, SM=2.5±0.1, IM=1.5±0.

1.

5. Silicate cement clinker prepared by the production method according to any one of claims 1 to 4.

6. The silicate cement clinker according to claim 5, characterized in that, Its mineral composition by mass percentage includes: tricalcium silicate 56.3%–58.5%, dicalcium silicate 13.1%–17.1%, tricalcium aluminate 4.7%–5.2%, tetracalcium aluminoferrite 8.7%–8.9%, and free calcium oxide 0.5%–1.4%.

7. The silicate cement clinker according to claim 6, characterized in that, The cement mortar made from the silicate cement clinker reaches strengths of 30 MPa, 45 MPa, and 60 MPa or higher after 3 days, 7 days, and 28 days, respectively.

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