Low-carbon high-performance cement clinker and preparation method thereof
By using a combination of steel slag and specific conditioning materials in cement clinker, a low-carbon, high-performance cement clinker with high activity R-type tricalcium silicate was prepared, solving the problem of steel slag utilization and improving the strength and resource utilization efficiency of cement clinker.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA BUILDING MATERIALS ACADEMY CO LTD
- Filing Date
- 2024-11-07
- Publication Date
- 2026-07-07
AI Technical Summary
Existing technologies cannot effectively utilize steel slag resources, leading to steel slag accumulation that causes environmental damage and resource waste. At the same time, when steel slag is used as a raw material for cement clinker, the tricalcium silicate crystal form cannot be effectively transformed into the highly active R-type, affecting the cementitious performance.
By replacing part of the cement raw meal with steel slag and adding conditioning materials such as lead-zinc slag, copper slag, manganese slag, and lithium slag, and through high-temperature calcination and rapid cooling, low-carbon, high-performance cement clinker containing highly active R-type tricalcium silicate is prepared.
It realizes the resource utilization of steel slag, reduces cement production costs, improves the strength performance of clinker, and does not introduce additional environmentally polluting components. It has a wide range of raw material sources and strong applicability.
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Figure CN119390364B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of building materials technology, and in particular to a low-carbon cement clinker and its preparation method. Background Technology
[0002] The chemical composition of steel slag is similar to that of silicate cement clinker. If the chemical composition of steel slag can be adjusted to meet the requirements of cement clinker, then steel slag can be used as a raw material for cement production. This would not only reduce carbon emissions in the cement production process, but also solve the environmental damage and resource waste caused by the long-standing accumulation of steel slag.
[0003] Steel slag has a high iron content, making grinding difficult and impacting its economic benefits as cement raw material. If granular steel slag, after iron beneficiation at steel plants, is directly fed into the kiln tail for high-temperature remodeling to replace part of the cement raw material in cement clinker production, its iron components facilitate the formation of a liquid phase at lower temperatures, promoting melting. The silicate phase already present in the steel slag can also act as a seed crystal induction nucleation agent, promoting clinker formation. During firing, larger steel slag particles break down under rapid heating, reducing their particle size. The surfaces of some steel slag particles begin to melt, forming more flux minerals, promoting the high-temperature firing reaction of the raw material and forming clinker minerals. Simultaneously, f-CaO in the steel slag is consumed and reacts to form the clinker mineral phase, and the low-activity γ-dicalcium silicate is remodeled into highly active dicalcium silicate. However, compared to traditional clinker, the main cementing mineral, tricalcium silicate, still primarily has an M-type crystal structure, resulting in lower cementing properties.
[0004] The search revealed that patent ZL201410265848.7 discloses a silicate cement clinker and its preparation method, which achieves the transformation of tricalcium silicate to R-crystal by adding magnesium-containing or phosphorus-containing raw materials to the raw meal to introduce ions; however, this patent still uses traditional raw materials to produce clinker and does not play a role in the resource utilization of industrial solid waste.
[0005] Patent CN201510382980.0 discloses a small-particle cement clinker, and patent CN201611145160.0 discloses a cement clinker and its preparation method and application. Both patents apply industrial waste to the production of cement clinker, but the crystal form of tricalcium silicate in the clinker remains unchanged.
[0006] Therefore, how to make full use of solid waste resources such as steel slag to save natural mineral resources and use solid waste for the preparation of high-performance low-carbon cement clinker has become a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0007] To address the above problems, this invention provides a low-carbon, high-performance cement clinker and its preparation method, which effectively utilizes steel slag, and the prepared clinker contains tricalcium silicate in a highly active R-crystal form, resulting in high clinker strength.
[0008] The technical solution of this invention is: a low-carbon, high-performance cement clinker, wherein the raw materials in the cement clinker, by weight percentage, include the following components: 75-90% raw meal, 5-20% steel slag, and 2-8% conditioning material.
[0009] The conditioning material includes at least two of lead-zinc slag, copper slag, manganese slag, and lithium slag.
[0010] The lead-zinc slag in the conditioning material is calculated as ZnO oxide, with a weight percentage of 0-5.5%; copper slag is calculated as CuO oxide, with a weight percentage of 0-2.0%; manganese slag is calculated as MnO2 oxide, with a weight percentage of 0-7.0%; and lithium slag is calculated as Li2O oxide, with a weight percentage of 0-3.0 wt%.
[0011] The minerals in the cement clinker, by weight percentage, include tricalcium silicate at a content of 45-70 wt%, and its crystal form is R-type.
[0012] The limestone saturation coefficient of the cement clinker ranges from 0.82 to 0.94%; the silicon content ranges from 1.7 to 2.7%; and the aluminum content ranges from 0.8 to 1.7%.
[0013] The steel slag was not ground, and the particle size of the steel slag was ≤15mm.
[0014] A method for preparing low-carbon, high-performance cement clinker includes the following steps:
[0015] Step 1: Select the type of conditioning material according to the composition of the required cement clinker, and determine the weight ratio of each conditioning material component;
[0016] Step 2: The raw materials, steel slag and the above-mentioned conditioning materials are thoroughly mixed, and then calcined at high temperature and rapidly cooled to room temperature to prepare cement clinker.
[0017] The high-temperature calcination temperature range is 1400℃~1500℃.
[0018] The obtained cement clinker was ground, and the fineness of the sample was controlled to be ground to a specific surface area of 320~360m². 2 / kg.
[0019] This invention uses steel slag to replace a portion of the cement raw meal in the preparation of cement clinker. This not only effectively realizes the resource utilization of steel slag but also reduces the production cost of cement clinker and conserves natural mineral resources. It proposes adding conditioning materials to stabilize tricalcium silicate (R-type) and improve clinker strength by ensuring the content of zinc, copper, manganese, or lithium in the clinker. No additional environmentally polluting components such as fluorine or sulfur are added, making it environmentally friendly, safe, and reliable. Furthermore, the raw materials used are widely available and have strong applicability. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the local characteristic fingerprint region of tricalcium silicate in the clinker sample of Comparative Example 1 of the present invention;
[0021] Figure 2 This is a schematic diagram of the local characteristic fingerprint region of tricalcium silicate in the clinker sample of Example 1 of the present invention. Detailed Implementation
[0022] The present invention will be further described below with reference to specific embodiments, but the following embodiments should not be construed as limiting the present invention.
[0023] This invention replaces part of the cement raw meal with steel slag and simultaneously incorporates conditioning materials containing specific trace elements to condition and clinkerize the steel slag, forming highly active R-crystal tricalcium silicate, and preparing low-carbon, high-performance cement clinker, thereby realizing the resource utilization of steel slag and improving the performance of clinker.
[0024] Clinker typically contains little to no impurity ions, primarily monoclinic M3 crystals. This invention introduces conditioning materials into the clinker, enabling not only the use of steel slag as a raw material for cement clinker production but also the introduction of certain amounts of Zn, Cu, Mn, and Li, thus producing low-carbon, high-performance cement clinker containing highly active R-type tricalcium silicate. The high performance of this invention is specifically manifested in its high compressive strength.
[0025] This invention discloses a low-carbon, high-performance cement clinker, wherein the raw materials in the cement clinker, by weight percentage, comprise the following components: 75-90% raw meal, 5-20% steel slag, and 2-8% conditioning material.
[0026] The conditioning materials include at least two of lead-zinc slag, copper slag, manganese slag, and lithium slag, and are used to adjust the content of trace components in clinker.
[0027] This invention proposes to replace part of the cement raw meal with steel slag to produce cement clinker. In order to further improve the strength properties of the cement clinker, it is proposed to add conditioning materials to improve the crystal form of the main minerals in the clinker.
[0028] Steel slag contains trace amounts of impurity ions, which can cause lattice distortion of tricalcium silicate, change the symmetry of the crystal structure, and induce the tricalcium silicate crystal form to transform into the highly active R-type, thereby improving the strength of the clinker.
[0029] In this invention, steel slag is a minor component, and the amount of impurity ions it introduces is relatively small, insufficient to induce a transformation in the tricalcium silicate crystal form. Therefore, by adding conditioning materials to supplement the quantity of these ions, combined with the "inducing" properties of steel slag, the goal of optimizing the tricalcium silicate crystal form is achieved.
[0030] The lead-zinc slag in the conditioning material is calculated as ZnO oxide, with a weight percentage of 0-5.5%; copper slag is calculated as CuO oxide, with a weight percentage of 0-2.0%; manganese slag is calculated as MnO2 oxide, with a weight percentage of 0-7.0%; and lithium slag is calculated as Li2O oxide, with a weight percentage of 0-3.0 wt%.
[0031] The minerals in the cement clinker, by weight percentage, include tricalcium silicate at a content of 45-70 wt%, and its crystal form is R-type.
[0032] The limestone saturation coefficient (KH) of the cement clinker ranges from 0.82 to 0.94%; the silica content (SM) ranges from 1.7 to 2.7%; and the aluminum content (IM) ranges from 0.8 to 1.7%.
[0033] The steel slag is unground, with a particle size ≤15mm. No grinding is required, thus not increasing production energy consumption.
[0034] A method for preparing low-carbon, high-performance cement clinker.
[0035] Includes the following steps:
[0036] Step 1: Select the type of conditioning material according to the composition of the required cement clinker, and determine the weight ratio of each conditioning material component;
[0037] Step 2: The raw materials, steel slag and the above-mentioned conditioning materials are thoroughly mixed, and then calcined at high temperature and rapidly cooled to room temperature to prepare cement clinker.
[0038] The low-carbon, high-performance cement clinker prepared by this invention contains trace amounts of zinc, copper, manganese, or lithium, as well as 45% to 70% of tricalcium silicate of type R.
[0039] The synergistic effect of elements such as Zn, Cu, Mn and Li can cause lattice distortion of tricalcium silicate, change the symmetry of the crystal structure, and induce the transformation of tricalcium silicate crystal form to the highly active R-type, thereby improving the strength of clinker.
[0040] The high-temperature calcination temperature range is 1400℃~1500℃.
[0041] The obtained cement clinker was ground, and the fineness of the sample was controlled to be ground to a specific surface area of 320~360m². 2 / kg.
[0042] The cement clinker prepared by this invention has high strength. When preparing cement of the same strength grade, the amount of clinker can be reduced and the amount of admixtures can be increased, thereby improving the application efficiency of clinker, saving energy, utilizing waste and reducing emissions.
[0043] The tricalcium silicate in the cement clinker prepared by this invention is of the R type, and the compressive strength of the clinker can be significantly improved compared with that of clinker without this technology.
[0044] This invention replaces part of the cement raw meal with steel slag, and simultaneously incorporates conditioning materials containing specific trace elements to condition and clinkerize the steel slag, while retaining the highly active R-crystal form of tricalcium silicate, thus preparing low-carbon, high-performance cement clinker, achieving resource utilization of steel slag and improvement of clinker performance.
[0045] Clinker typically contains little or no zinc, copper, manganese, or lithium, and tricalcium silicate is primarily monoclinic M3 crystal. This invention introduces conditioning materials into the clinker, enabling not only the use of steel slag as a raw material for cement clinker production but also the introduction of a certain amount of zinc, copper, manganese, or lithium into the clinker. This allows for the preparation of low-carbon, high-performance cement clinker containing highly active R-type tricalcium silicate.
[0046] The steel slag in this invention includes CaO, SiO2, Al2O3, MgO, and Fe2O3, etc.
[0047] Example 1:
[0048] The designed usage amounts of tempering material, steel slag, and raw meal are 5%, 20%, and 75%, respectively. The clinker yield values are KH=0.898, SM=2.50, and IM=1.31, respectively. The tempering material is prepared from copper slag. No tempering material is used in the clinker of Comparative Example 1. The calculated chemical composition of the clinker is shown in Table 2. The tempering material, steel slag, and raw meal are mixed evenly according to the calculated composition, and then calcined in a high-temperature furnace at 1430℃ followed by rapid cooling. The cooled clinker is crushed and ground, and the specific surface area is controlled to be (340±20) m². 2 / kg.
[0049] Table 2 Chemical composition of clinker (wt%)
[0050] <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> CaO MgO <![CDATA[SO3]]> <![CDATA[K2O]]> <![CDATA[Na2O]]> CuO Comparative Example 1 21.29 4.83 3.68 62.99 6.30 0.30 0.31 0.31 0 Example 1 21.16 4.80 3.66 62.61 6.26 0.29 0.31 0.31 0.60
[0051] XRD diffraction was used to test the clinker samples, and the X-ray diffraction peaks of the clinker in the characteristic fingerprint regions of 31°–33° and 51°–53° were obtained. Figure 1 As shown, no conditioning material was used in the clinker of Comparative Example 1, but the diffraction pattern between 31° and 33° was affected by the solid solution of other impurities. The interplanar spacing of (224) is close, and the diffraction peaks of the two planes merge; there is a shoulder peak to the right of the (620) diffraction peak between 51° and 53°, which is the (040) diffraction peak of the monoclinic M3 crystal form. Therefore, the tricalcium silicate in the clinker of Comparative Example 1 is of the M3 crystal form. Figure 2 As shown, since the clinker of Example 1 used tempering material, the diffraction spectrum has only two diffraction peaks at 32° to 33°, and only one R-type (220) crystal plane diffraction peak between 51° and 53°, indicating that the tricalcium silicate in the clinker of Example 1 is R-type.
[0052] The clinker prepared above was mixed with 5% gypsum, and the compressive strength of the clinker samples was tested according to GB / T17671-1999. The water-cement ratio was 0.5, and water was added to make 40mm×40mm×40mm mortar blocks. After standard curing, the compressive strength of the blocks at 3 days, 7 days, 28 days, and 90 days was measured, as shown in Table 3.
[0053] Table 3. Free calcium content, specific surface area, and strength properties of clinker samples
[0054]
[0055] Example 2:
[0056] The designed usage amounts of tempering material, steel slag, and raw meal were 6%, 14%, and 80%, respectively. The clinker yield values were KH=0.902, SM=2.45, and IM=1.35, respectively. The tempering material was prepared from lead-zinc slag. No tempering material was used in the clinker of Comparative Example 2. The calculated chemical composition of the clinker is shown in Table 4. The tempering material, steel slag, and raw meal were mixed evenly according to the calculated composition, and then calcined in a high-temperature furnace at 1450℃ followed by rapid cooling. The cooled clinker was crushed and ground, and the specific surface area was controlled to be (340±20) m². 2 / kg.
[0057] Table 4. Chemical composition of clinker (wt%)
[0058] <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> CaO MgO <![CDATA[SO3]]> <![CDATA[K2O]]> <![CDATA[Na2O]]> ZnO Comparative Example 2 21.13 4.96 3.67 63.03 6.29 0.30 0.31 0.31 0 Example 2 20.07 4.72 3.49 59.89 5.97 0.28 0.29 0.30 5.00
[0059] XRD diffraction was used to test the clinker samples. The tricalcium silicate in the clinker of Comparative Example 2 was of the M3 crystal form, and the tricalcium silicate in the clinker of Example 2 was of the R crystal form.
[0060] The clinker prepared above was mixed with 5% gypsum, and the compressive strength of the clinker samples was tested according to GB / T17671-1999. With a water-cement ratio of 0.5, water was added and mixed to form 40mm×40mm×40mm mortar blocks. After standard curing, the compressive strength at 3 days, 7 days, 28 days, and 90 days was measured, as shown in Table 5.
[0061] Table 5. Free calcium content, specific surface area, and strength properties of clinker samples
[0062]
[0063] Example 3:
[0064] The designed usage amounts of tempering material, steel slag, and raw meal were 4%, 6%, and 90%, respectively, with the tempering material containing phosphorus. The designed clinker yield values were KH=0.892, SM=2.40, and IM=1.42, respectively. The tempering material was prepared from manganese slag. No tempering material was used in the clinker of Comparative Example 3. The calculated chemical composition of the clinker is shown in Table 6. The tempering material, steel slag, and raw meal were mixed evenly according to the calculated composition, and then calcined in a high-temperature furnace at 1410℃ followed by rapid cooling. The cooled clinker was crushed and ground, and the specific surface area of the clinker was controlled to be (340±20) m². 2 / kg.
[0065] Table 6. Chemical composition of clinker (wt%)
[0066] <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> CaO MgO <![CDATA[SO3]]> <![CDATA[K2O]]> <![CDATA[Na2O]]> <![CDATA[MnO2]]> Comparative Example 3 21.16 5.17 3.64 62.88 6.24 0.29 0.31 0.31 0 Example 3 21.07 5.15 3.63 62.60 6.21 0.29 0.30 0.31 4.5
[0067] XRD diffraction was used to test the clinker samples. The tricalcium silicate in the clinker of Comparative Example 3 was of the M3 crystal form, and the tricalcium silicate in the clinker of Example 3 was of the R crystal form.
[0068] The clinker prepared above was mixed with 5% gypsum, and the compressive strength of the clinker samples was tested according to GB / T17671-1999. With a water-cement ratio of 0.5, water was added and mixed to form 40mm×40mm×40mm mortar blocks. After standard curing, the compressive strength at 3 days, 7 days, 28 days, and 90 days was measured, as shown in Table 7.
[0069] Table 7. Free calcium content, specific surface area, and strength properties of clinker samples
[0070]
[0071] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within the spirit and scope of its protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.
Claims
1. A low-carbon, high-performance cement clinker, characterized in that, The raw materials in the cement clinker, by weight percentage, include the following components: 75-90% raw meal, 5-20% steel slag, and 2-8% quenching and tempering materials. The conditioning material includes at least two of lead-zinc slag, copper slag, manganese slag, and lithium slag; The lead-zinc slag in the conditioning material, calculated as ZnO oxide, has a weight percentage of 0-5.5%; the copper slag, calculated as CuO oxide, has a weight percentage of 0-2.0%; the manganese slag, calculated as MnO2 oxide, has a weight percentage of 0-7.0%; and the lithium slag, calculated as Li2O oxide, has a weight percentage of 0-3.0 wt%. The minerals in the cement clinker, by weight percentage, include tricalcium silicate at a content of 45-70 wt%, and its crystal form is R-type.
2. The low-carbon, high-performance cement clinker according to claim 1, characterized in that, The lime saturation coefficient of the cement clinker ranges from 0.82 to 0.94; the silicon content ranges from 1.7 to 2.7; and the aluminum content ranges from 0.8 to 1.
7.
3. The low-carbon, high-performance cement clinker according to claim 1, characterized in that, The steel slag was not ground, and the particle size of the steel slag was ≤15mm.
4. A method for preparing the low-carbon high-performance cement clinker according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Select the type of conditioning material according to the composition of the required cement clinker, and determine the weight ratio of each conditioning material component; Step 2: The raw materials, steel slag and the above-mentioned conditioning materials are thoroughly mixed, and then calcined at high temperature and rapidly cooled to room temperature to prepare cement clinker.
5. The method for preparing low-carbon high-performance cement clinker according to claim 4, characterized in that, The high-temperature calcination temperature range is 1400℃~1500℃.
6. The method for preparing low-carbon high-performance cement clinker according to claim 4, characterized in that, The obtained cement clinker was ground, and the fineness of the sample was controlled to be ground to a specific surface area of 320~360m². 2 / kg.