Waste incineration fly ash-based high belite sulphoaluminate cement clinker and preparation method thereof

Abstract

The invention belongs to the technical field of building materials, and provides a waste incineration fly ash-based high belite sulphoaluminate cement clinker and a preparation method thereof. The clinker is prepared from the following raw materials in parts by mass: 32.25 to 34.25 parts of waste incineration fly ash, 41.34 to 43.34 parts of carbide slag, 0.36 to 2.36 parts of ferric oxide and 22.05 to 24.05 parts of bauxite tailings. According to the method, the waste incineration fly ash serves as a preparation raw material, the fly ash contains high-content calcium sulfate and heavy metal ions, the components enter C2S mineral lattices in the calcination process, lattice distortion is caused, and the activity of C2S is improved. Meanwhile, heavy metal ions in the fly ash are effectively solidified in a clinker mineral structure, the leaching risk of heavy metal and environmental pollution are reduced, and harmless treatment of the fly ash is achieved. The waste incineration fly ash based high belite sulphoaluminate cement clinker prepared by the preparation method disclosed by the invention has excellent early compressive strength.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a garbage incineration fly ash-based high-belite sulphoaluminate cement clinker and a preparation method thereof. Background Art

[0002] The development of High Belite Calcium Sulphoaluminate Cement (HB-CSA) began in the 1980s. It is a new type of low-carbon cement developed on the basis of traditional sulphoaluminate cement (CSA) by reducing the content of calcium sulphoaluminate (C4A3$) and increasing the content of dicalcium silicate (C2S). Compared with CSA, the content of C4A3$ in HB-CSA is reduced and the content of C2S is increased. This mineral composition characteristic not only reduces the demand for high-grade aluminum raw materials, but also effectively alleviates the problem of strength shrinkage of cement in the later stage of hydration. At the same time, its production cost is also lower than that of traditional CSA cement. However, with the decrease of the content of highly active C4A3$, the overall hydration rate of HB-CSA slows down, and it loses the most distinctive advantage of CSA in rapid hardening and early strength, making it difficult to meet the needs of some practical projects. Therefore, the activation treatment of C2S has become the focus of current research.

[0003] In addition, with the acceleration of urbanization and the improvement of people's living standards, the amount of domestic waste generated continues to increase. As an efficient way of waste disposal, waste incineration is widely used because it can significantly reduce the volume and mass of waste and recover heat energy. However, a large amount of fly ash is produced during the waste incineration process. These fly ashes contain a variety of harmful substances, such as heavy metals, soluble salts and dioxins. If not properly handled, they will pose a serious threat to the environment and human health. Traditional methods for treating waste incineration fly ash mainly include landfill and stabilization treatment, but these methods have problems such as high cost and secondary pollution, and it is difficult to achieve resource utilization.

[0004] In summary, it is of great significance to provide a HB-CSA with high early strength and efficiently treat the fly ash generated by waste incineration. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems existing in the prior art and provide a high-belite sulphoaluminate cement clinker based on waste incineration fly ash and a preparation method thereof.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a high-belite sulphoaluminate cement clinker based on waste incineration fly ash, comprising the following raw materials in parts by weight:

[0008] 32.25-34.25 parts of waste incineration fly ash, 41.34-43.34 parts of carbide slag, 0.36-2.36 parts of ferric oxide and 22.05-24.05 parts of bauxite tailings.

[0009] Preferably, the mass fraction of calcium oxide in the waste incineration fly ash is 44.9%, the mass fraction of silicon dioxide is 5.11%, the mass fraction of aluminum oxide is 1.8%, the mass fraction of iron oxide is 2.03%, and the mass fraction of sulfur trioxide is 10.1%.

[0010] Preferably, the mass fraction of calcium oxide in carbide slag is 70.32%, the mass fraction of silicon dioxide is 2.41%, the mass fraction of aluminum oxide is 1.07%, the mass fraction of iron oxide is 0.32%, and the mass fraction of sulfur trioxide is 0.52%.

[0011] Preferably, the mass fraction of calcium oxide in the bauxite tailings is 1.44%, the mass fraction of silicon dioxide is 37.22%, the mass fraction of aluminum oxide is 36.94%, the mass fraction of iron oxide is 4.95%, and the mass fraction of sulfur trioxide is 0.45%.

[0012] The present invention also provides a method for preparing the waste incineration fly ash-based high-belite sulphoaluminate cement clinker, comprising the following steps:

[0013] The waste incineration fly ash, carbide slag, ferric oxide and bauxite tailings are mixed and ground to obtain a mixture; the mixture is calcined to obtain the waste incineration fly ash-based high-belite sulphoaluminate cement clinker.

[0014] Preferably, the mass fraction of the mixed material having a particle size less than 80 μm is ≥90%.

[0015] Preferably, the calcination comprises a first calcination, a second calcination and a third calcination performed sequentially;

[0016] The temperature of the first calcination was 700°C, the temperature of the second calcination was 1000°C, and the temperature of the third calcination was 1250°C.

[0017] Preferably, the holding time of the first calcination, the second calcination and the third calcination is independently 20 minutes.

[0018] The beneficial effects of the present invention are:

[0019] The present invention provides a high-belite sulphoaluminate cement clinker based on fly ash from garbage incineration, comprising the following raw materials by mass: 32.25 to 34.25 parts of fly ash from garbage incineration, 41.34 to 43.34 parts of carbide slag, 0.36 to 2.36 parts of ferric oxide and 22.05 to 24.05 parts of bauxite tailings. The present invention uses fly ash from garbage incineration as one of the raw materials for preparing high-belite sulphoaluminate cement. The fly ash has a high content of calcium sulfate and heavy metal ions. During the calcination process, these components enter the C2S mineral lattice, resulting in lattice distortion and increasing the activity of C2S. At the same time, the heavy metal ions in the fly ash are effectively solidified in the clinker mineral structure, reducing the risk of heavy metal leaching and environmental pollution, and achieving harmless treatment of fly ash. In addition, the present invention makes full use of the effective components in fly ash by rationally optimizing the ratio of each raw material and the calcination system during preparation, thereby reducing the energy consumption of cement production and the demand for natural raw materials. The produced cement clinker not only has excellent performance, but also reduces carbon dioxide emissions, achieving the goal of resource utilization and low-carbon environmental protection. The waste incineration fly ash-based high-belite sulphoaluminate cement clinker prepared by the present invention has good early compressive strength, mechanical properties and durability, meets the needs of modern building materials for high performance and sustainable development, and has significant economic and environmental benefits. DETAILED DESCRIPTION

[0020] The present invention provides a high-belite sulphoaluminate cement clinker based on waste incineration fly ash, comprising the following raw materials in parts by weight:

[0021] 32.25-34.25 parts of waste incineration fly ash, 41.34-43.34 parts of carbide slag, 0.36-2.36 parts of ferric oxide and 22.05-24.05 parts of bauxite tailings.

[0022] In the present invention, the mass fraction of the waste incineration fly ash is 32.25 to 34.25 parts, preferably 32.47 to 34.19 parts, more preferably 32.75 to 33.94 parts, and even more preferably 33.15 to 33.55 parts.

[0023] In the present invention, the mass fraction of carbide slag is 41.34 to 43.34 parts, preferably 41.65 to 43.23 parts, more preferably 41.95 to 42.95 parts, and even more preferably 42.25 to 42.45 parts.

[0024] In the present invention, the mass fraction of ferric oxide is 0.36 to 2.36 parts, preferably 0.53 to 2.11 parts, more preferably 0.83 to 2.01 parts, and even more preferably 1.56 to 1.76 parts.

[0025] In the present invention, the mass fraction of the bauxite tailings is 22.05 to 24.05 parts, preferably 22.55 to 23.55 parts, more preferably 22.75 to 23.25 parts, and even more preferably 22.95 to 23.05 parts.

[0026] In the present invention, the mass fraction of calcium oxide in the waste incineration fly ash is preferably 44.9%, the mass fraction of silicon dioxide is preferably 5.11%, the mass fraction of aluminum oxide is preferably 1.8%, the mass fraction of iron oxide is preferably 2.03%, the mass fraction of sulfur trioxide is preferably 10.1%, and other impurities are the remainder.

[0027] In the present invention, the mass fraction of calcium oxide in carbide slag is preferably 70.32%, the mass fraction of silicon dioxide is preferably 2.41%, the mass fraction of aluminum oxide is preferably 1.07%, the mass fraction of iron oxide is preferably 0.32%, the mass fraction of sulfur trioxide is preferably 0.52%, and other impurities are the remainder.

[0028] In the present invention, the purity of ferric oxide is preferably 100%.

[0029] In the present invention, the mass fraction of calcium oxide in the bauxite tailings is preferably 1.44%, the mass fraction of silicon dioxide is preferably 37.22%, the mass fraction of aluminum oxide is preferably 36.94%, the mass fraction of iron oxide is preferably 4.95%, the mass fraction of sulfur trioxide is preferably 0.45%, and other impurities are the remainder.

[0030] The present invention also provides a method for preparing the waste incineration fly ash-based high-belite sulphoaluminate cement clinker, comprising the following steps:

[0031] The waste incineration fly ash, carbide slag, ferric oxide and bauxite tailings are mixed and ground to obtain a mixture; the mixture is calcined to obtain the waste incineration fly ash-based high-belite sulphoaluminate cement clinker.

[0032] In the present invention, before mixing waste incineration fly ash, carbide slag, ferric oxide and bauxite tailings, it is preferred that the waste incineration fly ash, carbide slag, ferric oxide and bauxite tailings are crushed and ground independently in sequence to obtain ground particles of waste incineration fly ash, ground particles of carbide slag, ground particles of ferric oxide and ground particles of bauxite tailings; then, each ground particle is dried independently, mixed after drying, and ground to obtain a mixture.

[0033] In the present invention, the particle sizes of the ground particles of waste incineration fly ash, the ground particles of carbide slag, the ground particles of ferric oxide and the ground particles of bauxite tailings are independently preferably ≤0.75mm, further preferably ≤0.73mm, and more preferably ≤0.70mm; the target moisture content of each ground particle after drying is independently preferably ≤0.5%, further preferably ≤0.3%, and more preferably ≤0.2%.

[0034] In the present invention, after grinding, the mixture is divided into a mixture with a particle size less than 80 μm and a mixture with a particle size greater than or equal to 80 μm according to the particle size; the mass fraction of the mixture with a particle size less than 80 μm in the mixture is preferably ≥90%, further preferably ≥95%, and more preferably ≥98%.

[0035] In the present invention, the calcination preferably comprises a first calcination, a second calcination, and a third calcination performed sequentially.

[0036] In the present invention, the temperature of the first calcination is preferably 700°C, the temperature of the second calcination is preferably 1000°C, and the temperature of the third calcination is preferably 1250°C.

[0037] In the present invention, the holding time of the first calcination, the second calcination and the third calcination is preferably independently 20 minutes.

[0038] In the present invention, after the third calcination is completed, the obtained system is cooled to obtain the waste incineration fly ash-based high-belite sulphoaluminate cement clinker; the cooling rate of the cooling is preferably 50°C / min, and the target temperature of the cooling is preferably 20-30°C, further preferably 22-28°C, and more preferably 25°C.

[0039] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0040] Example 1

[0041] In this embodiment, the waste incineration fly ash-based high-belite sulphoaluminate cement clinker comprises the following raw materials in parts by weight:

[0042] 34.19 parts of waste incineration fly ash, 41.65 parts of carbide slag, 2.11 parts of ferric oxide and 22.05 parts of bauxite tailings; among which, the mass fraction of calcium oxide in the waste incineration fly ash is 44.9%, the mass fraction of silicon dioxide is 5.11%, the mass fraction of aluminum oxide is 1.8%, the mass fraction of ferric oxide is 2.03%, the mass fraction of sulfur trioxide is 10.1%, and the remainder is other impurities; the mass fraction of calcium oxide in the carbide slag is 70.32%, the mass fraction of silicon dioxide is The mass fraction of aluminum oxide is 2.41%, the mass fraction of aluminum oxide is 1.07%, the mass fraction of iron oxide is 0.32%, the mass fraction of sulfur trioxide is 0.52%, and the balance is other impurities; the purity of iron oxide is 100%; the mass fraction of calcium oxide in bauxite tailings is 1.44%, the mass fraction of silicon dioxide is 37.22%, the mass fraction of aluminum oxide is 36.94%, the mass fraction of iron oxide is 4.95%, the mass fraction of sulfur trioxide is 0.45%, and the balance is other impurities.

[0043] The preparation method comprises the following steps: crushing and grinding waste incineration fly ash, carbide slag, ferric oxide and bauxite tailings independently and sequentially to obtain ground particles of waste incineration fly ash with a particle size of 0.70 mm, ground particles of carbide slag with a particle size of 0.70 mm, ground particles of ferric oxide with a particle size of 0.70 mm and ground particles of bauxite tailings with a particle size of 0.70 mm; then, drying the above ground particles independently until the moisture content is independently 0. The mixture is calcined at 700°C for 20 min in a preheater, then placed in a rotary kiln and calcined at 1000°C for 20 min, and finally calcined at 1250°C for 20 min. After the calcination, the obtained system is cooled to 25°C at a cooling rate of 50°C / min to obtain a waste incineration fly ash-based high-belite sulphoaluminate cement clinker.

[0044] Example 2

[0045] In this embodiment, the waste incineration fly ash-based high-belite sulphoaluminate cement clinker comprises the following raw materials in parts by weight:

[0046] 32.47 parts of waste incineration fly ash, 42.95 parts of carbide slag, 0.53 parts of ferric oxide and 24.05 parts of bauxite tailings; among which, the mass fraction of calcium oxide in the waste incineration fly ash is 44.9%, the mass fraction of silicon dioxide is 5.11%, the mass fraction of aluminum oxide is 1.8%, the mass fraction of ferric oxide is 2.03%, the mass fraction of sulfur trioxide is 10.1%, and the rest is other impurities; the mass fraction of calcium oxide in the carbide slag is 70.32%, the mass fraction of silicon dioxide is The mass fraction of aluminum oxide is 2.41%, the mass fraction of aluminum oxide is 1.07%, the mass fraction of iron oxide is 0.32%, the mass fraction of sulfur trioxide is 0.52%, and the balance is other impurities; the purity of iron oxide is 100%; the mass fraction of calcium oxide in bauxite tailings is 1.44%, the mass fraction of silicon dioxide is 37.22%, the mass fraction of aluminum oxide is 36.94%, the mass fraction of iron oxide is 4.95%, the mass fraction of sulfur trioxide is 0.45%, and the balance is other impurities.

[0047] The preparation method comprises the following steps: crushing and grinding waste incineration fly ash, carbide slag, ferric oxide and bauxite tailings independently and sequentially to obtain ground particles of waste incineration fly ash with a particle size of 0.70 mm, ground particles of carbide slag with a particle size of 0.70 mm, ground particles of ferric oxide with a particle size of 0.70 mm and ground particles of bauxite tailings with a particle size of 0.70 mm; then, drying the above ground particles independently until the moisture content is independently 0. The mixture is calcined at 700°C for 20 min in a preheater, then placed in a rotary kiln and calcined at 1000°C for 20 min, and finally calcined at 1250°C for 20 min. After the calcination, the obtained system is cooled to 25°C at a cooling rate of 50°C / min to obtain a waste incineration fly ash-based high-belite sulphoaluminate cement clinker.

[0048] Example 3

[0049] In this embodiment, the waste incineration fly ash-based high-belite sulphoaluminate cement clinker comprises the following raw materials in parts by weight:

[0050] 33.94 parts of waste incineration fly ash, 42.45 parts of carbide slag, 1.56 parts of ferric oxide and 22.05 parts of bauxite tailings; among which, the mass fraction of calcium oxide in the waste incineration fly ash is 44.9%, the mass fraction of silicon dioxide is 5.11%, the mass fraction of aluminum oxide is 1.8%, the mass fraction of ferric oxide is 2.03%, the mass fraction of sulfur trioxide is 10.1%, and the rest is other impurities; the mass fraction of calcium oxide in the carbide slag is 70.32%, the mass fraction of silicon dioxide is The mass fraction of aluminum oxide is 2.41%, the mass fraction of aluminum oxide is 1.07%, the mass fraction of iron oxide is 0.32%, the mass fraction of sulfur trioxide is 0.52%, and the balance is other impurities; the purity of iron oxide is 100%; the mass fraction of calcium oxide in bauxite tailings is 1.44%, the mass fraction of silicon dioxide is 37.22%, the mass fraction of aluminum oxide is 36.94%, the mass fraction of iron oxide is 4.95%, the mass fraction of sulfur trioxide is 0.45%, and the balance is other impurities.

[0051] The preparation method comprises the following steps: crushing and grinding waste incineration fly ash, carbide slag, ferric oxide and bauxite tailings independently and sequentially to obtain ground particles of waste incineration fly ash with a particle size of 0.70 mm, ground particles of carbide slag with a particle size of 0.70 mm, ground particles of ferric oxide with a particle size of 0.70 mm and ground particles of bauxite tailings with a particle size of 0.70 mm; then, drying the above ground particles independently until the moisture content is independently 0. The mixture is calcined at 700°C for 20 min in a preheater, then placed in a rotary kiln and calcined at 1000°C for 20 min, and finally calcined at 1250°C for 20 min. After the calcination, the obtained system is cooled to 25°C at a cooling rate of 50°C / min to obtain a waste incineration fly ash-based high-belite sulphoaluminate cement clinker.

[0052] Comparative Example 1

[0053] Commercially available high-belite sulphoaluminate cement (purchased from Zhucheng Jiuqi Building Materials Co., Ltd.).

[0054] The waste incineration fly ash-based high-belite sulphoaluminate cement clinker obtained in Examples 1 to 3 and the commercially available high-belite sulphoaluminate cement in Comparative Example 1 were respectively used as cementitious materials, and four corresponding samples were prepared according to a water-cement ratio of 0.5. The 6h compressive strength of the four samples was tested (test standard: DBJT 13-196-2021 "Cement Paste Material Mix Design and Test Procedure"), and the early compressive strength test results of different samples were obtained, as shown in Table 1.

[0055] Table 1 Early compressive strength test results of different samples

[0056] Case Example 1 Example 2 Example 3 Comparative Example 1 6h compressive strength / MPa 30.6 31.8 32.6 18

[0057] It can be seen from the above embodiments that the present invention provides a high-belite sulphoaluminate cement clinker based on waste incineration fly ash, comprising the following raw materials by mass: 32.25-34.25 parts of waste incineration fly ash, 41.34-43.34 parts of carbide slag, 0.36-2.36 parts of ferric oxide and 22.05-24.05 parts of bauxite tailings. The present invention uses waste incineration fly ash as one of the raw materials for preparing high-belite sulphoaluminate cement. The fly ash has a high content of calcium sulfate and heavy metal ions. During the calcination process, these components enter the C2S mineral lattice, resulting in lattice distortion and increasing the activity of C2S. At the same time, the heavy metal ions in the fly ash are effectively solidified in the clinker mineral structure, reducing the risk of heavy metal leaching and environmental pollution, and realizing the harmless treatment of fly ash. In addition, the present invention makes full use of the effective components in fly ash by rationally optimizing the ratio of each raw material and the calcination system during preparation, thereby reducing the energy consumption of cement production and the demand for natural raw materials. The produced cement clinker not only has excellent performance, but also reduces carbon dioxide emissions, achieving the goal of resource utilization and low-carbon environmental protection. The waste incineration fly ash-based high-belite sulphoaluminate cement clinker prepared by the present invention has good early compressive strength, mechanical properties and durability, meets the needs of modern building materials for high performance and sustainable development, and has significant economic and environmental benefits.

[0058] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-belite sulphoaluminate cement clinker based on waste incineration fly ash, It is characterized in that Contains the following raw materials by mass: 32.25-34.25 parts of waste incineration fly ash, 41.34-43.34 parts of carbide slag, 0.36-2.36 parts of ferric oxide and 22.05-24.05 parts of bauxite tailings.

2. The waste incineration fly ash-based high-belite sulphoaluminate cement clinker according to claim 1, It is characterized in that The mass fraction of calcium oxide in waste incineration fly ash is 44.9%, the mass fraction of silicon dioxide is 5.11%, the mass fraction of aluminum oxide is 1.8%, the mass fraction of iron oxide is 2.03%, and the mass fraction of sulfur trioxide is 10.1%.

3. The waste incineration fly ash-based high-belite sulphoaluminate cement clinker according to claim 1 or 2, It is characterized in that The mass fraction of calcium oxide in carbide slag is 70.32%, the mass fraction of silicon dioxide is 2.41%, the mass fraction of aluminum oxide is 1.07%, the mass fraction of iron oxide is 0.32%, and the mass fraction of sulfur trioxide is 0.52%.

4. The waste incineration fly ash-based high-belite sulphoaluminate cement clinker according to claim 3, It is characterized in that The mass fraction of calcium oxide in bauxite tailings is 1.44%, the mass fraction of silicon dioxide is 37.22%, the mass fraction of aluminum oxide is 36.94%, the mass fraction of iron oxide is 4.95%, and the mass fraction of sulfur trioxide is 0.45%.

5. The method for preparing high-belite sulphoaluminate cement clinker based on waste incineration fly ash according to any one of claims 1 to 4, It is characterized in that It includes the following steps: The waste incineration fly ash, carbide slag, ferric oxide and bauxite tailings are mixed and ground to obtain a mixture; the mixture is calcined to obtain the waste incineration fly ash-based high-belite sulphoaluminate cement clinker.

6. The method for preparing high-belite sulphoaluminate cement clinker based on waste incineration fly ash according to claim 5, It is characterized in that The mass fraction of the mixture with particle size less than 80 μm is ≥ 90%.

7. The method for preparing high-belite sulphoaluminate cement clinker based on waste incineration fly ash according to claim 5 or 6, It is characterized in that The calcination comprises a first calcination, a second calcination and a third calcination performed sequentially; The temperature of the first calcination was 700°C, the temperature of the second calcination was 1000°C, and the temperature of the third calcination was 1250°C.

8. The method for preparing high-belite sulphoaluminate cement clinker based on waste incineration fly ash according to claim 7, It is characterized in that The holding time of the first calcination, the second calcination and the third calcination is independently 20 minutes.