High-strength and high-impermeability aluminate cement and preparation method thereof

Abstract

The invention discloses high-strength and high-impermeability aluminate cement and a preparation method thereof, particularly relates to the technical field of cement, and relates to the high-strength and high-impermeability aluminate cement and the preparation method thereof. The high-strength and high-impermeability aluminate cement is prepared from the following raw materials in parts by weight: 48 to 55 parts of bauxite, 10 to 15 parts of modified forsterite, 3 to 5 parts of aluminum borate, 12 to 15 parts of limestone, 8 to 10 parts of gypsum, 4 to 6 parts of titanium dioxide, 2 to 3 parts of lithium carbonate and 2 to 3 parts of silica fume. The microstructures formed under the guidance of the biomineralization template agent effectively reduce the porosity and aperture in the cement, reduce permeation channels of moisture and harmful media, and improve the impermeability of the cement.

Description

Technical Field

[0001] The present invention relates to the technical field of cement, and more specifically, to a high-strength and high-permeability resistant aluminate cement and a preparation method thereof. Background Art

[0002] Aluminate cement is widely used in the construction field. Its characteristics such as rapid hardening, high strength, sulfate erosion resistance, and high temperature resistance make it a commonly used material in many projects. Therefore, developing an aluminate cement with both high strength and high permeability resistance and its preparation method has become a key problem urgently needed to be solved in the industry.

[0003] The cement in the related technology includes bauxite, limestone, and iron ore. Among them, bauxite is the main aluminum source of aluminate cement, and bauxite provides alumina components. During the high-temperature calcination process, alumina reacts with calcium oxide in limestone to form calcium aluminate minerals, which are the main hydraulic mineral components of aluminate cement and directly determine the basic performance of the cement. Limestone mainly provides calcium oxide for the cement, and calcium oxide reacts with alumina to form various calcium aluminate minerals. Iron ore can introduce iron oxide components, adjust the mineral composition and liquid phase amount of cement clinker during the calcination process, promote the formation and development of minerals, improve the burning performance of the cement, reduce the calcination temperature, and save energy.

[0004] However, in actual use, there are still some disadvantages. For example, the strength is low. The mineral composition of the aluminate cement prepared by the related technology is relatively single, mainly prepared from bauxite and limestone, and the types of calcium aluminate minerals formed are limited. The anti-permeability ability is poor. There are many large pores inside the aluminate cement prepared by the related technology, and these pores are interconnected to form a permeation channel. It is difficult to balance the performance. The types of raw materials of the aluminate cement prepared by the related technology are few, and the proportion is relatively fixed, and it is difficult to optimize the performance by adjusting the raw materials. Summary of the Invention

[0005] In order to improve the above problems and reduce the problems of poor strength, poor mechanical properties, and low filtration efficiency of the high-strength and high-permeability resistant aluminate cement in the related technology, the present invention particularly provides a high-strength and high-permeability resistant aluminate cement and a preparation method thereof to solve the problems raised in the above background art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A high-strength and high-permeability resistant aluminate cement, comprising the following steps:

[0008] C1. Select a special-grade bauxite ore with an Al2O3 content ≥ 85%, coarsely crush it to a particle size < 5 mm by a jaw crusher, then perform surface activation treatment on the bauxite powder with a 10% dilute hydrochloric acid solution, and then dehydrate it and dry it at 120 °C for 2 h to obtain bauxite;

[0009] C2. Grind the raw forsterite ore to 200 mesh, then place it in a high-temperature tubular furnace and calcine it at 1500 °C for 2 h under a N2 atmosphere. After the calcined product is quenched rapidly with water, wet grinding is carried out for 4 h by adding 0.5% sodium polyacrylate dispersant through a planetary ball mill to obtain modified forsterite;

[0010] C3. Extract the calcium carbonate template agent from deep-sea corals. After removing the organic matrix by dissolving with dilute acetic acid, prepare porous CaCO3 microspheres with a particle size of 20 - 50 nm by spray drying method. Disperse the microspheres in deionized water to prepare a suspension with a solid content of 15%. Add 0.3% chitosan for surface modification, then mix it with 0.1 mol / L Ca(NO3)2 solution, add 0.05% polyvinyl alcohol as a film-forming agent, adjust the pH to 9.0 with ammonia water, and stir in a 60 °C constant temperature water bath for 30 min to obtain a mineralization precursor solution.

[0011] C4. Put bauxite, modified forsterite, aluminum borate, limestone, gypsum, titanium dioxide, lithium carbonate, and silica fume into a mixer and mix at a speed of 45 r / min for 40 min to make a uniform raw material. Press the raw material into a cylindrical green body with a diameter of φ50×20 mm and put it into a graphite crucible in a plasma reaction furnace. During this period, introduce argon with a flow rate of 50 L / min and maintain the furnace pressure at 5×10 -3 Pa. Start the radio frequency power supply and gradually increase the power to 80 kW to raise the furnace temperature to 1200 °C within 30 min and maintain the constant temperature reaction for 2 h; after the reaction ends, immediately introduce liquid nitrogen into the furnace and carry out rapid quenching under the condition of a cooling rate of 500 °C / min. The quenched clinker is crushed to 10 mm by a jaw crusher and then classified to a particle size of 3 - 5 mm through a vibrating screen to obtain cement clinker;

[0012] C5. Immerse the cement clinker obtained in C4 into the mineralization precursor solution obtained in C3, rotate at 150 r / min, at a temperature of 45 °C, and cure for 72 h. During this period, supplement 10% volume of the mineralization precursor solution every 12 h. Wash the cured particles 3 times with deionized water, then soak them in an ethanol solution containing 5% silane coupling agent for 2 h, and take them out and dry them in a blast drying oven at 80 °C for 12 h to obtain the modified cement clinker;

[0013] C6. Place the modified cement clinker obtained in C5 into a tube mill and carry out rough grinding under the conditions of a feeding rate of 15 t / h, an inlet and outlet pressure difference of 0.08 MPa, a ventilation volume of 2000 m 3 / h, and a specific surface area of the discharged material of 300 m 2 / kg. Then mix the roughly ground material with 2% TiO2 and 3% lithium-based admixture and put them into a vertical roller mill. Roll at 8 MPa, the grinding table rotates at 35 r / min, and the specific surface area is 380 - 420 m 2 / kg, and perform fine grinding to obtain high-strength and high-permeability-resistant aluminous cement.

[0014] Preferably, the components and weight parts of the raw materials for preparing the high-strength and high-permeability-resistant aluminous cement are as follows: 48 - 55 parts of bauxite, 10 - 15 parts of modified forsterite, 3 - 5 parts of aluminum borate, 12 - 15 parts of limestone, 8 - 10 parts of gypsum, 4 - 6 parts of titanium dioxide, 2 - 3 parts of lithium carbonate, and 2 - 3 parts of silica fume.

[0015] Preferably, in the C1 surface activation treatment, the bauxite ore is mixed with a 10% dilute hydrochloric acid solution at a liquid-solid ratio of (2 - 4):1.

[0016] Preferably, in the C2, the wet-ground calcined product is wet-ground under the condition of a ball-to-material ratio of (4 - 6):1.

[0017] Preferably, in the C3, the suspension of the surface-modified calcium carbonate template agent is mixed with a 0.1mol / L Ca(NO3)2 solution at a volume ratio of 1:(2 - 4).

[0018] Preferably, in the C5, the cement clinker is immersed in the mineralization precursor solution under the condition of a liquid-solid ratio of 5:1.

[0019] The technical effects and advantages of the present invention:

[0020] 1. Through plasma-assisted synthesis, the present invention forms a cement mineral phase with a special structure. At the same time, bio-mineralization regulation makes the cement hydration products have a denser microstructure, thus significantly improving the strength of the cement.

[0021] 2. The microstructure formed by the bio-mineralization template agent of the present invention effectively reduces the porosity and pore diameter inside the cement, reduces the penetration channels of water and harmful media, and improves the impermeability of the cement.

[0022] 3. The present invention uses bauxite to provide an aluminum source to form aluminous minerals, which is the main source of the cement strength. Modified forsterite promotes the formation of magnesium aluminate spinel, enhancing the high-temperature resistance and mechanical strength of the cement. Aluminum borate is used as a flux to reduce the calcination temperature, promote mineral formation, induce crystal nucleus generation, and optimize the cement microstructure. Limestone adjusts the setting time of the cement, reacts with bauxite to form calcium aluminate, increasing the early strength. Gypsum delays the hydration rate of the cement, prevents flash setting, forms ettringite, and improves the early strength. Titanium dioxide photocatalytically decomposes harmful substances, improves the impermeability, refines the cement pores, and enhances the density. Lithium carbonate inhibits the polymorphic transformation of aluminous minerals, reduces volume shrinkage, and enhances the durability and crack resistance of the cement. Silica fume fills the cement pores, improves the density, and the pozzolanic reaction generates C-S-H gel, enhancing the strength and impermeability. Specific embodiments

[0023] The present invention will be further described in detail below in conjunction with the embodiments of the present invention. The raw materials used in the examples and embodiments of the present invention are all common commercially available materials except as specifically described below;

[0024] Preparation Examples 1 - 5

[0025] A high-strength and high-permeability-resistant aluminous cement, the preparation components and their corresponding proportions are shown in the following table, and it is prepared by the following preparation method:

[0026] C1. Select special-grade bauxite ore with an Al2O3 content of ≥85%. After being coarsely crushed by a jaw crusher to a particle size of <5 mm, the bauxite powder is surface-activated with a 10% dilute hydrochloric acid solution at a liquid-solid ratio of 3:1, and then dehydrated and dried at 120°C for 2 h to obtain bauxite;

[0027] C2. Grind the original forsterite powder to 200 meshes, then place it in a high-temperature tube furnace and calcine it at 1500°C for 2 h in an N2 atmosphere. After the calcined product is quenched and rapidly cooled with water, 0.5% sodium polyacrylate dispersant is added through a planetary ball mill, and wet grinding is carried out at a ball-to-material ratio of 5:1 for 4 h to obtain modified forsterite;

[0028] C3. Extract calcium carbonate template agent from deep-sea corals. After removing the organic matrix by dissolving with dilute acetic acid, porous CaCO3 microspheres with a particle size of 20 - 50 nm are prepared by spray drying method. The microspheres are dispersed in deionized water to prepare a suspension with a solid content of 15%, 0.3% chitosan is added for surface modification, and then it is mixed with 0.1 mol / L Ca(NO3)2 solution at a volume ratio of 1:3. 0.05% polyvinyl alcohol is added as a film-forming agent, the pH is adjusted to 9.0 with ammonia water, and it is stirred in a 60°C constant temperature water bath for 30 min to obtain a mineralization precursor solution.

[0029] C4. Put bauxite, modified forsterite, aluminum borate, limestone, gypsum, titanium dioxide, lithium carbonate, and silica fume into a mixer and mix them at a speed of 45 r / min for 40 min to make a uniform raw meal. Press the raw meal into a cylindrical blank with a size of m50×20 mm, put it into a graphite crucible in a plasma reaction furnace, and during this period, introduce argon with a flow rate of 50 L / min and maintain the furnace pressure at 5×10 - 3 Pa, start the radio frequency power supply, gradually increase the power to 80 kW, so that the furnace temperature rises to 1200°C within 30 min, and maintain the constant temperature reaction for 2 h; after the reaction is completed, immediately introduce liquid nitrogen into the furnace and perform rapid quenching at a cooling rate of 500°C / min. The quenched clinker is crushed to 10 mm by a jaw crusher and then classified to a particle size of 3 - 5 mm through a vibrating screen to obtain cement clinker;

[0030] C5. Immerse the cement clinker obtained in C4 into the mineralization precursor solution obtained in C3 under the condition of a liquid-solid ratio of 5:1, at a rotation speed of 150 r / min, a temperature of 45 °C, and cure for 72 h. During the curing process, supplement 10% by volume of the mineralization precursor solution every 12 h. After curing, wash the particles 3 times with deionized water, then immerse them in an ethanol solution containing 5% silane coupling agent for 2 h, take them out and dry them in a blast drying oven at 80 °C for 12 h to obtain the modified cement clinker;

[0031] C6. Place the modified cement clinker obtained in C5 into a tube mill, and under the conditions of a feeding rate of 15 t / h, an inlet-outlet pressure difference of 0.08 MPa, a ventilation volume of 2000 m 3 / h, and a specific surface area of the milled material of 300 m 2 / kg, carry out rough grinding. Then mix the roughly ground material with 2% TiO2 and 3% lithium-based admixture and put them into a vertical roller mill, and under the conditions of a roll pressure of 8 MPa, a grinding table rotation speed of 35 r / min, and a specific surface area of 380 - 420 m 2 / kg, carry out fine grinding to obtain high-strength and high impermeability aluminate cement.

[0032] Table: Each component of the preparation raw materials and their mass ratios (g) in Preparation Examples 1 - 5

[0033]

[0034]

[0035] Preparation Example 6

[0036] A high-strength and high impermeability aluminate cement, which is different from Preparation Example 1 in that the preparation method is as follows:

[0037] C1. Select special-grade bauxite ore with an Al2O3 content of ≥85%, crush it roughly to a particle size of <5 mm by a jaw crusher, then carry out surface activation treatment on the bauxite powder with a 10% dilute hydrochloric acid solution under the condition of a liquid-solid ratio of 2:1, then dehydrate it, and dry it at 120 °C for 2 h to obtain bauxite;

[0038] C2. Grind the original forsterite ore powder to 200 meshes, then place it in a high-temperature tube furnace, calcine it at 1500 °C for 2 h under a N2 atmosphere. After the calcined product is quenched rapidly with water, add 0.5% sodium polyacrylate dispersant through a planetary ball mill, and carry out wet grinding for 4 h under the condition of a ball-to-material ratio of 5:1 to obtain modified forsterite;

[0039] C3. Extract calcium carbonate templating agent from deep-sea corals. After removing the organic matrix by dissolving in dilute acetic acid, prepare porous CaCO3 microspheres with a particle size of 20 - 50 nm by spray drying method. Disperse the microspheres in deionized water to prepare a suspension with a solid content of 15%. Add 0.3% chitosan for surface modification, then mix with 0.1 mol / L Ca(NO3)2 solution at a volume ratio of 1:3. Add 0.05% polyvinyl alcohol as a film-forming agent, adjust the pH to 9.0 with ammonia water, and stir in a 60°C constant temperature water bath for 30 min to obtain a mineralization precursor solution.

[0040] C4. Put bauxite, modified forsterite, aluminum borate, limestone, gypsum, titanium dioxide, lithium carbonate, and silica fume into a mixer and mix at a speed of 45 r / min for 40 min to make a uniform raw material. Press the raw material into a cylindrical green body of 250×20 mm, put it into a graphite crucible in a plasma reaction furnace. During this period, introduce argon with a flow rate of 50 L / min and maintain the furnace pressure at 5×10 - 3 Pa. Start the radio frequency power supply, gradually increase the power to 80 kW, and raise the furnace temperature to 1200°C within 30 min. Maintain the constant temperature reaction for 2 h. After the reaction ends, immediately introduce liquid nitrogen into the furnace and perform rapid quenching under the condition of a cooling rate of 500°C / min. The quenched clinker is crushed to 10 mm by a jaw crusher and then classified to a particle size of 3 - 5 mm through a vibrating screen to obtain cement clinker.

[0041] C5. Immerse the cement clinker obtained in C4 in the mineralization precursor solution obtained in C3 under the condition of a liquid-solid ratio of 5:1, rotate at 150 r / min, at a temperature of 45°C, and cure for 72 h. During this period, supplement 10% volume of the mineralization precursor solution every 12 h. Wash the cured particles 3 times with deionized water, then soak them in an ethanol solution containing 5% silane coupling agent for 2 h, take them out and dry them in a blast drying oven at 80°C for 12 h to obtain the modified cement clinker.

[0042] C6. Put the modified cement clinker obtained in C5 into a tube mill and perform rough grinding under the conditions of a feeding rate of 15 t / h, an inlet and outlet pressure difference of 0.08 MPa, a ventilation volume of 2000 m 3 / h, and a specific surface area of the milled material of 300 m 2 / kg. Then mix the roughly ground material with 2% TiO2 and 3% lithium-based admixture and put them into a vertical roller mill, and perform fine grinding at a roll pressure of 8 MPa, a grinding table speed of 35 r / min, and a specific surface area of 380 - 420 m 2 / kg to obtain high-strength and high impermeability aluminate cement.

[0043] Preparation Example 7

[0044] A high-strength and high-permeability-resistant aluminate cement, which is different from Preparation Example 1, and the preparation method is as follows:

[0045] C1. Select special-grade bauxite ore with an Al2O3 content of ≥85%, crush it roughly to a particle size of <5 mm by a jaw crusher, then perform surface activation treatment on the bauxite powder with a 10% dilute hydrochloric acid solution under a liquid-solid ratio of 4:1, and then dehydrate it and dry it at 120°C for 2 h to obtain bauxite;

[0046] C2. Grind the original forsterite powder to 200 meshes, then place it in a high-temperature tubular furnace and calcine it at 1500°C for 2 h under an N2 atmosphere. After the calcined product is quenched rapidly by water, add 0.5% sodium polyacrylate dispersant through a planetary ball mill and perform wet grinding for 4 h under a ball-to-material ratio of 5:1 to obtain modified forsterite;

[0047] C3. Extract calcium carbonate template agent from deep-sea corals, remove the organic matrix by dissolving it with dilute acetic acid, and then prepare porous CaCO3 microspheres with a particle size of 20 - 50 nm by spray drying method. Disperse the microspheres in deionized water to prepare a suspension with a solid content of 15%, add 0.3% chitosan for surface modification, then mix it with 0.1 mol / L Ca(NO3)2 solution at a volume ratio of 1:3, add 0.05% polyvinyl alcohol as a film-forming agent, adjust the pH to 9.0 with ammonia water, and stir it in a 60°C constant temperature water bath for 30 min to obtain a mineralization precursor solution.

[0048] C4. Put bauxite, modified forsterite, aluminum borate, limestone, gypsum, titanium dioxide, lithium carbonate, and silica fume into a mixer and mix them at a speed of 45 r / min for 40 min to make a uniform raw material. Press the raw material into a cylindrical green body with a diameter of φ50×20 mm, put it into a graphite crucible in a plasma reaction furnace, and during this period, introduce argon with a flow rate of 50 L / min and maintain the furnace pressure at 5×10 -3 Pa, start the radio frequency power supply, gradually increase the power to 80 kW, and raise the furnace temperature to 1200°C within 30 min and maintain the constant temperature reaction for 2 h; after the reaction ends, immediately introduce liquid nitrogen into the furnace and perform rapid quenching under a cooling rate of 500°C / min. The quenched clinker is crushed to 10 mm by a jaw crusher and then classified to a particle size of 3 - 5 mm through a vibrating screen to obtain cement clinker;

[0049] C5. Immerse the cement clinker obtained in C4 in the mineralization precursor solution obtained in C3 under a liquid-solid ratio of 5:1, rotate at a speed of 150 r / min, at a temperature of 45°C, and cure for 72 h. During this period, supplement 10% volume of the mineralization precursor solution every 12 h. Wash the cured particles 3 times with deionized water, then soak them in an ethanol solution containing 5% silane coupling agent for 2 h, take them out and dry them in a blast drying oven at 80°C for 12 h to obtain the modified cement clinker;

[0050] C6. Place the modified cement clinker obtained in C5 into a tube mill. Under the conditions of a feeding rate of 15 t / h, an inlet and outlet pressure difference of 0.08 MPa, a ventilation volume of 2000 m 3 / h, and a specific surface area of the milled material of 300 m 2 / kg, carry out rough grinding. Then mix the roughly ground material with 2% TiO2 and 3% lithium-based admixture and put them into a vertical roller mill. Under the conditions of a roll pressure of 8 MPa, a grinding table speed of 35 r / min, and a specific surface area of 380 - 420 m 2 / kg, carry out fine grinding to obtain high-strength and high-permeability-resistant aluminate cement.

[0051] Preparation Example 8

[0052] A high-strength and high-permeability-resistant aluminate cement, which is different from that in Preparation Example 1 in that the preparation method is as follows:

[0053] C1. Select special-grade bauxite ore with an Al2O3 content of ≥85%. After being coarsely crushed to a particle size of <5 mm by a jaw crusher, carry out surface activation treatment on the bauxite powder with a 10% dilute hydrochloric acid solution under the condition of a liquid-solid ratio of 3:1. Then, after dehydration, dry it at 120 °C for 2 h to obtain bauxite;

[0054] C2. Grind the raw forsterite powder to 200 meshes, then place it in a high-temperature tube furnace, calcine it at 1500 °C for 2 h under a N2 atmosphere. After the calcined product is quenched and rapidly cooled with water, add 0.5% sodium polyacrylate dispersant through a planetary ball mill, and carry out wet grinding for 4 h under the condition of a ball-to-material ratio of 4:1 to obtain modified forsterite;

[0055] C3. Extract a calcium carbonate template agent from deep-sea corals. After removing the organic matrix by dissolving it with dilute acetic acid, use the spray drying method to prepare porous CaCO3 microspheres with a particle size of 20 - 50 nm. Disperse the microspheres in deionized water, prepare a suspension with a solid content of 15%, add 0.3% chitosan for surface modification, then mix it with a 0.1 mol / L Ca(NO3)2 solution at a volume ratio of 1:3, add 0.05% polyvinyl alcohol as a film-forming agent, adjust the pH to 9.0 with ammonia water, and stir it in a 60 °C constant temperature water bath for 30 min to obtain a mineralization precursor solution.

[0056] C4. Put bauxite, modified forsterite, aluminum borate, limestone, gypsum, titanium dioxide, lithium carbonate, and silica fume into a mixer, mix them at a speed of 45 r / min for 40 min to make a uniform raw meal. Press the raw meal into a cylindrical green body with a diameter of φ50 × 20 mm, and put it into a graphite crucible of a plasma reaction furnace. During this period, introduce argon with a flow rate of 50 L / min and maintain the furnace pressure at 5 × 10 -3Pa, start the radio frequency power supply, gradually increase the power to 80 kW, raise the temperature in the furnace to 1200 °C within 30 min, and maintain the constant temperature reaction for 2 h; after the reaction, immediately introduce liquid nitrogen into the furnace and perform rapid quenching under the condition of a cooling rate of 500 °C / min. The quenched clinker is crushed to 10 mm by a jaw crusher and then classified to a particle size of 3-5 mm through a vibrating screen to obtain cement clinker;

[0057] C5. Immerse the cement clinker obtained in C4 in the mineralization precursor solution obtained in C3 under the condition of a liquid-solid ratio of 5:1, rotate at 150 r / min, maintain the temperature at 45 °C, and cure for 72 h. During this period, supplement 10% by volume of the mineralization precursor solution every 12 h. Wash the cured particles 3 times with deionized water, then immerse them in an ethanol solution containing 5% silane coupling agent for 2 h, take them out and dry them in a blast drying oven at 80 °C for 12 h to obtain the modified cement clinker;

[0058] C6. Place the modified cement clinker obtained in C5 in a tube mill, under the conditions of a feeding rate of 15 t / h, an inlet and outlet pressure difference of 0.08 MPa, a ventilation volume of 2000 m 3 / h, and a specific surface area of the milled material of 300 m 2 / kg for rough grinding. Then mix the roughly ground material with 2% TiO2 and 3% lithium-based admixture and put them into a vertical roller mill. Under the conditions of a roll pressure of 8 MPa, a grinding table speed of 35 r / min, and a specific surface area of 380 - 420 m 2 / kg, carry out fine grinding to obtain high-strength and high-permeability-resistant aluminate cement.

[0059] Preparation Example 9

[0060] A high-strength and high-permeability-resistant aluminate cement, which is different from Preparation Example 1 in that the preparation method is as follows:

[0061] C1. Select special-grade bauxite ore with an Al2O3 content of ≥85%. After being coarsely crushed to a particle size of <5 mm by a jaw crusher, perform surface activation treatment on the bauxite powder with a 10% dilute hydrochloric acid solution under the condition of a liquid-solid ratio of 3:1. Then, after dehydration, dry it at 120 °C for 2 h to obtain bauxite;

[0062] C2. Grind the original forsterite ore to 200 mesh, then place it in a high-temperature tube furnace, calcine it at 1500 °C for 2 h under a N2 atmosphere. After the calcined product is quenched and rapidly cooled with water, add 0.5% sodium polyacrylate dispersant through a planetary ball mill and perform wet grinding for 4 h under the condition of a ball-to-material ratio of 6:1 to obtain modified forsterite;

[0063] C3. Extract calcium carbonate templating agent from deep - sea corals. After removing the organic matrix by dissolving in dilute acetic acid, prepare porous CaCO3 microspheres with a particle size of 20 - 50 nm by spray - drying method. Disperse the microspheres in deionized water to prepare a suspension with a solid content of 15%. Add 0.3% chitosan for surface modification, then mix with 0.1 mol / L Ca(NO3)2 solution at a volume ratio of 1:3. Add 0.05% polyvinyl alcohol as a film - forming agent, adjust the pH to 9.0 with ammonia water, and stir in a 60 °C constant - temperature water bath for 30 min to obtain a mineralization precursor solution.

[0064] C4. Put bauxite, modified forsterite, aluminum borate, limestone, gypsum, titanium dioxide, lithium carbonate, and silica fume into a mixer and mix at a speed of 45 r / min for 40 min to make a uniform raw material. Press the raw material into a cylindrical green body with a size of φ50×20 mm and place it in a graphite crucible of a plasma reaction furnace. During this period, introduce argon with a flow rate of 50 L / min and maintain the furnace pressure at 5×10 - 3 Pa. Start the radio - frequency power supply and gradually increase the power to 80 kW to raise the furnace temperature to 1200 °C within 30 min and maintain the constant - temperature reaction for 2 h. After the reaction is completed, immediately introduce liquid nitrogen into the furnace and perform rapid quenching under the condition of a cooling rate of 500 °C / min. The quenched clinker is crushed to 10 mm by a jaw crusher and then classified to a particle size of 3 - 5 mm through a vibrating screen to obtain cement clinker.

[0065] C5. Immerse the cement clinker obtained in C4 in the mineralization precursor solution obtained in C3 under the condition of a liquid - to - solid ratio of 5:1, rotate at 150 r / min, maintain the temperature at 45 °C, and cure for 72 h. During this period, supplement 10% volume of the mineralization precursor solution every 12 h. Wash the cured particles 3 times with deionized water, then soak them in an ethanol solution containing 5% silane coupling agent for 2 h, and take them out and dry in a blast drying oven at 80 °C for 12 h to obtain the modified cement clinker.

[0066] C6. Place the modified cement clinker obtained in C5 in a tube mill and perform rough grinding under the conditions of a feeding rate of 15 t / h, an inlet - outlet pressure difference of 0.08 MPa, a ventilation volume of 2000 m 3 / h, and a specific surface area of the mill - exit material of 300 m 2 / kg. Then mix the roughly ground material with 2% TiO2 and 3% lithium - based admixture and put them into a vertical roller mill. Perform fine grinding under the conditions of a roll pressure of 8 MPa, a grinding - disk rotation speed of 35 r / min, and a specific surface area of 380 - 420 m 2 / kg to obtain high - strength and high - impermeability aluminate cement.

[0067] Preparation Example 10

[0068] A high - strength and high - impermeability aluminate cement, which is different from that of Preparation Example 1 in that the preparation method is as follows:

[0069] C1. Select special-grade bauxite ore with an Al2O3 content of ≥85%. After coarse crushing it to a particle size of <5 mm with a jaw crusher, surface activate the bauxite powder with a 10% dilute hydrochloric acid solution under the condition of a liquid-solid ratio of 3:1. Then, after dehydration, dry it at 120 °C for 2 h to obtain bauxite;

[0070] C2. Grind the original forsterite ore to 200 mesh, then place it in a high-temperature tube furnace and calcine it at 1500 °C for 2 h under a N2 atmosphere. After the calcined product is quenched and rapidly cooled with water, add 0.5% sodium polyacrylate dispersant through a planetary ball mill and carry out wet grinding for 4 h under the condition of a ball-to-material ratio of 5:1 to obtain modified forsterite;

[0071] C3. Extract calcium carbonate template agent from deep-sea corals. After removing the organic matrix by dissolving it with dilute acetic acid, prepare porous CaCO3 microspheres with a particle size of 20 - 50 nm by spray drying method. Disperse the microspheres in deionized water to prepare a suspension with a solid content of 15%. Add 0.3% chitosan for surface modification, then mix it with 0.1 mol / L Ca(NO3)2 solution at a volume ratio of 1:2, add 0.05% polyvinyl alcohol as a film-forming agent, adjust the pH to 9.0 with ammonia water, and stir in a 60 °C constant temperature water bath for 30 min to obtain a mineralization precursor solution.

[0072] C4. Put bauxite, modified forsterite, aluminum borate, limestone, gypsum, titanium dioxide, lithium carbonate, and silica fume into a mixer and mix them at a speed of 45 r / min for 40 min to make a uniform raw material. Press the raw material into a cylindrical green body with a diameter of φ50 × 20 mm and put it into a graphite crucible of a plasma reaction furnace. During this period, introduce argon with a flow rate of 50 L / min and maintain the furnace pressure at 5×10 -3 Pa, start the radio frequency power supply, gradually increase the power to 80 kW, and raise the furnace temperature to 1200 °C within 30 min and maintain the constant temperature reaction for 2 h; after the reaction ends, immediately introduce liquid nitrogen into the furnace and carry out rapid quenching under the condition of a cooling rate of 500 °C / min. The quenched clinker is crushed to 10 mm with a jaw crusher and then classified to a particle size of 3 - 5 mm through a vibrating screen to obtain cement clinker;

[0073] C5. Immerse the cement clinker obtained in C4 in the mineralization precursor solution obtained in C3 under the condition of a liquid-solid ratio of 5:1, rotate at 150 r / min, at a temperature of 45 °C, and cure for 72 h. During this period, supplement 10% volume of the mineralization precursor solution every 12 h. Wash the cured particles 3 times with deionized water, then soak them in an ethanol solution containing 5% silane coupling agent for 2 h, take them out and dry them in a blast drying oven at 80 °C for 12 h to obtain the modified cement clinker;

[0074] C6. Place the modified cement clinker obtained in C5 into a tube mill. Under the conditions of a feeding rate of 15 t / h, an inlet-outlet pressure difference of 0.08 MPa, a ventilation volume of 2000 m 3 / h, and a specific surface area of the milled material of 300 m 2 / kg, conduct rough grinding. Then mix the roughly ground material with 2% TiO2 and 3% lithium-based admixture and put them into a vertical roller mill. Under the conditions of a roll pressure of 8 MPa, a grinding table speed of 35 r / min, and a specific surface area of 380 - 420 m 2 / kg, conduct fine grinding to obtain high-strength and high impermeability aluminous cement.

[0075] Preparation Example 11

[0076] A high-strength and high impermeability aluminous cement, which is different from that in Preparation Example 1. The preparation method is as follows:

[0077] C1. Select special-grade bauxite ore with an Al2O3 content ≥ 85%. After being roughly crushed by a jaw crusher to a particle size < 5 mm, conduct surface activation treatment on the bauxite powder with a 10% dilute hydrochloric acid solution under the condition of a liquid-solid ratio of 3:1. Then, after dehydration, dry it at 120 °C for 2 h to obtain bauxite.

[0078] C2. Grind the original forsterite powder to 200 meshes, then place it in a high-temperature tube furnace, calcine it at 1500 °C for 2 h under a N2 atmosphere. After the calcined product is quenched and rapidly cooled with water, add 0.5% sodium polyacrylate dispersant through a planetary ball mill, and conduct wet grinding for 4 h under the condition of a ball-to-material ratio of 5:1 to obtain modified forsterite.

[0079] C3. Extract calcium carbonate templating agent from deep-sea corals. After removing the organic matrix by dissolving with dilute acetic acid, prepare porous CaCO3 microspheres with a particle size of 20 - 50 nm by spray drying method. Disperse the microspheres in deionized water, prepare a suspension with a solid content of 15%, add 0.3% chitosan for surface modification, then mix it with 0.1 mol / L Ca(NO3)2 solution at a volume ratio of 1:4, add 0.05% polyvinyl alcohol as a film-forming agent, adjust the pH to 9.0 with ammonia water, and stir in a 60 °C constant temperature water bath for 30 min to obtain a mineralization precursor solution.

[0080] C4. Put bauxite, modified forsterite, aluminum borate, limestone, gypsum, titanium dioxide, lithium carbonate, and silica fume into a mixer, mix them at a speed of 45 r / min for 40 min to make a uniform raw meal. Press the raw meal into a cylindrical green body with a diameter of φ50 × 20 mm, put it into a graphite crucible of a plasma reaction furnace. During this period, introduce argon with a flow rate of 50 L / min and maintain the furnace pressure at 5 × 10 -3Pa, start the radio frequency power supply, gradually increase the power to 80 kW, raise the temperature in the furnace to 1200 °C within 30 min, and maintain the constant temperature reaction for 2 h; after the reaction, immediately introduce liquid nitrogen into the furnace and perform rapid quenching at a cooling rate of 500 °C / min. The quenched clinker is crushed to 10 mm by a jaw crusher and then classified to a particle size of 3-5 mm through a vibrating screen to obtain cement clinker;

[0081] C5. Immerse the cement clinker obtained in C4 into the mineralization precursor solution obtained in C3 under the condition of a liquid-solid ratio of 5:1, rotate at 150 r / min, maintain the temperature at 45 °C, and cure for 72 h. During the curing process, add 10% by volume of the mineralization precursor solution every 12 h. The cured particles are washed 3 times with deionized water, then immersed in an ethanol solution containing 5% silane coupling agent for 2 h, taken out and dried in a blast drying oven at 80 °C for 12 h to obtain the modified cement clinker;

[0082] C6. Place the modified cement clinker obtained in C5 into a tube mill, under the conditions of a feeding rate of 15 t / h, an inlet and outlet pressure difference of 0.08 MPa, a ventilation volume of 2000 m 3 / h, and a specific surface area of the milled material of 300 m 2 / kg for rough grinding, and then mix the roughly ground material with 2% TiO2 and 3% lithium-based admixture and put them into a vertical roller mill, under the conditions of a roll pressure of 8 MPa, a grinding table speed of 35 r / min, and a specific surface area of 380 - 420 m 2 / kg for fine grinding to obtain high-strength and high-permeability resistance aluminate cement.

[0083] Preparation Example 12

[0084] A high-strength and high-permeability resistance aluminate cement, different from Preparation Example 1, the preparation method is as follows:

[0085] C1. Select special-grade bauxite ore with an Al2O3 content ≥ 85%, after coarse crushing to a particle size < 5 mm by a jaw crusher, perform surface activation treatment on the bauxite powder with 10% dilute hydrochloric acid solution under the condition of a liquid-solid ratio of 3:1, then dehydrate and dry at 120 °C for 2 h to obtain bauxite;

[0086] C2. Grind the raw forsterite powder to 200 mesh, then place it in a high-temperature tube furnace, calcine at 1500 °C for 2 h under a N2 atmosphere, after the calcined product is quenched rapidly with water, add 0.5% sodium polyacrylate dispersant through a planetary ball mill and perform wet grinding for 4 h under the condition of a ball-to-material ratio of 5:1 to obtain modified forsterite;

[0087] C3. Extract calcium carbonate templating agent from deep-sea corals. After removing the organic matrix by dissolving in dilute acetic acid, prepare porous CaCO3 microspheres with a particle size of 20 - 50 nm using spray drying method. Disperse the microspheres in deionized water to prepare a suspension with a solid content of 15%. Add 0.3% chitosan for surface modification, then mix with 0.1 mol / L Ca(NO3)2 solution at a volume ratio of 1:3. Add 0.05% polyvinyl alcohol as a film-forming agent, adjust the pH to 9.0 with ammonia water, and stir in a constant temperature water bath at 60 °C for 30 min to obtain a mineralization precursor solution.

[0088] C4. Put bauxite, modified forsterite, aluminum borate, limestone, gypsum, titanium dioxide, lithium carbonate, and silica fume into a mixer and mix at a speed of 45 r / min for 40 min to make a uniform raw material. Press the raw material into a cylindrical green body with a diameter of φ50×20 mm and place it in a graphite crucible of a plasma reaction furnace. During this period, introduce argon with a flow rate of 50 L / min and maintain the furnace pressure at 5×10 -3 Pa. Start the radio frequency power supply and gradually increase the power to 80 kW to raise the furnace temperature to 1200 °C within 30 min and maintain the constant temperature reaction for 2 h. After the reaction ends, immediately introduce liquid nitrogen into the furnace and perform rapid quenching under the condition of a cooling rate of 500 °C / min. The quenched clinker is crushed to 10 mm by a jaw crusher and then classified to a particle size of 3 - 5 mm through a vibrating screen to obtain cement clinker.

[0089] C5. Immerse the cement clinker obtained in C4 into the mineralization precursor solution obtained in C3 under the condition of a liquid-solid ratio of 4:1, rotate at a speed of 150 r / min, at a temperature of 45 °C, and cure for 72 h. During this period, supplement 10% volume of the mineralization precursor solution every 12 h. Wash the cured particles 3 times with deionized water, then immerse them in an ethanol solution containing 5% silane coupling agent for 2 h, take them out and dry them in a blast drying oven at 80 °C for 12 h to obtain the modified cement clinker.

[0090] C6. Place the modified cement clinker obtained in C5 into a tube mill and perform rough grinding under the conditions of a feeding rate of 15 t / h, an inlet and outlet pressure difference of 0.08 MPa, a ventilation volume of 2000 m 3 / h, and a specific surface area of the milled material of 300 m 2 / kg. Then mix the roughly ground material with 2% TiO2 and 3% lithium-based admixture and put them into a vertical roller mill. Perform fine grinding at a roll pressure of 8 MPa, a grinding disc speed of 35 r / min, and a specific surface area of 380 - 420 m 2 / kg to obtain high-strength and high impermeability aluminate cement.

[0091] Preparation Example 13

[0092] A high-strength and high impermeability aluminate cement, which is different from that of Preparation Example 1 in that the preparation method is as follows:

[0093] C1. Select special-grade bauxite ore with an Al2O3 content of ≥85%. After coarse crushing it to a particle size of <5 mm with a jaw crusher, surface activation treatment is carried out on the bauxite powder with a 10% dilute hydrochloric acid solution under a liquid-solid ratio of 3:1. Then, after dehydration, it is dried at 120 °C for 2 h to obtain bauxite;

[0094] C2. Grind the original forsterite ore to 200 mesh, then place it in a high-temperature tube furnace and calcine it at 1500 °C for 2 h under a N2 atmosphere. After the calcined product is quenched rapidly with water, 0.5% sodium polyacrylate dispersant is added through a planetary ball mill, and wet grinding is carried out for 4 h under a ball-to-material ratio of 5:1 to obtain modified forsterite;

[0095] C3. Extract calcium carbonate template agent from deep-sea corals. After removing the organic matrix by dissolving it with dilute acetic acid, porous CaCO3 microspheres with a particle size of 20 - 50 nm are prepared by spray drying method. The microspheres are dispersed in deionized water to prepare a suspension with a solid content of 15%. 0.3% chitosan is added for surface modification, and then it is mixed with 0.1 mol / L Ca(NO3)2 solution at a volume ratio of 1:3. 0.05% polyvinyl alcohol is added as a film-forming agent, and the pH is adjusted to 9.0 with ammonia water. Stir for 30 min in a 60 °C constant-temperature water bath to obtain a mineralization precursor solution.

[0096] C4. Put bauxite, modified forsterite, aluminum borate, limestone, gypsum, titanium dioxide, lithium carbonate, and silica fume into a mixer and mix them at a speed of 45 r / min for 40 min to make a uniform raw material. Press the raw material into a cylindrical green body with a diameter of φ50×20 mm and put it into a graphite crucible in a plasma reaction furnace. During this period, argon with a flow rate of 50 L / min is introduced and the pressure in the furnace is maintained at 5×10 -3 Pa. Start the radio frequency power supply and gradually increase the power to 80 kW to raise the temperature in the furnace to 1200 °C within 30 min and maintain the constant-temperature reaction for 2 h; after the reaction is completed, immediately introduce liquid nitrogen into the furnace and perform rapid quenching under a cooling rate of 500 °C / min. The quenched clinker is crushed to 10 mm with a jaw crusher and then classified to a particle size of 3 - 5 mm through a vibrating screen to obtain cement clinker;

[0097] C5. Immerse the cement clinker obtained in C4 in the mineralization precursor solution obtained in C3 under a liquid-solid ratio of 6:1, rotate at a speed of 150 r / min, at a temperature of 45 °C, and cure for 72 h. During this period, 10% volume of the mineralization precursor solution is supplemented every 12 h. The cured particles are washed 3 times with deionized water, then immersed in an ethanol solution containing 5% silane coupling agent for 2 h, taken out and dried in a blast drying oven at 80 °C for 12 h to obtain the modified cement clinker;

[0098] C6. Place the modified cement clinker obtained in C5 into a tube mill. Under the conditions of a feeding rate of 15 t / h, an inlet-outlet pressure difference of 0.08 MPa, a ventilation rate of 2000 m 3 / h, and a specific surface area of the milled material of 300 m 2 / kg, conduct rough grinding. Then mix the roughly ground material with 2% TiO2 and 3% lithium-based admixture and put them into a vertical roller mill. Under the conditions of a roll pressure of 8 MPa, a grinding table speed of 35 r / min, and a specific surface area of 380 - 420 m 2 / kg, conduct fine grinding to obtain high-strength and high impermeability aluminate cement.

[0099] Performance detection test

[0100] Select the high-strength and high impermeability aluminate cement prepared in each example for inspection. The test subjects are 130 portions of high-strength and high impermeability aluminate cement, with 10 portions in each group. Detect their strength and impermeability. The specific detection steps are as follows:

[0101] Strength:

[0102] First, sample the high-strength and high impermeability aluminate cement prepared in the example after natural drying for 7 days. Use a compression testing machine to detect the compressive strength of the sample. Control the loading rate at 2400 N / s, record the failure load value. Compressive strength = failure load / compressive area, and use this to characterize the strength of the high-strength and high impermeability aluminate cement. The detection results and evaluation criteria are as follows:

[0103] Compressive strength > 50 MPa (regarded as high strength);

[0104] Compressive strength < 50 MPa (regarded as low strength).

[0105] Impermeability:

[0106] First, sample the high-strength and high impermeability aluminate cement prepared in the example after natural drying for 7 days. Use a paraffin - rosin sealant with a ratio of 3:1 to seal the sample, and then test its impermeability. First, apply an initial water pressure of 0.1 MPa and maintain it for 2 h. Then increase the pressure by 0.1 MPa every 8 h until water seepage occurs in the sample. Record the initial water seepage pressure and calculate the permeability coefficient, and use this to characterize the impermeability of the high-strength and high impermeability aluminate cement. The detection results and evaluation criteria are as follows:

[0107] Initial water seepage pressure ≥ 1.2 MPa, permeability coefficient ≤ 1×10 -10 cm / s (regarded as strong impermeability);

[0108] Initial water seepage pressure < 1.2 MPa, permeability coefficient > 1×10 -10 cm / s (regarded as weak impermeability).

[0109] Specifically, the high-strength and high-permeability-resistant aluminate cement prepared above is the high-strength and high-permeability-resistant aluminate cement produced by maintaining the normal production method. For the defective high-strength and high-permeability-resistant aluminate cement produced, the data of this high-strength and high-permeability-resistant aluminate cement is discarded and not counted.

[0110] Examples 1 - 5

[0111] A high-strength and high-permeability-resistant aluminate cement, and the corresponding relationships of the preparation methods used are shown in the following table.

[0112] Table: Comparison table of the usage of high-strength and high-permeability-resistant aluminate cement in Examples 1 - 5

[0113] Group High-strength and high impermeability aluminate cement Example 1 Prepared from Preparation Example 1 Example 2 Prepared from Preparation Example 2 Example 3 Prepared from Preparation Example 3 Example 4 Prepared from Preparation Example 4 Example 5 Prepared from Preparation Example 5

[0114] Extract the high-strength and high-permeability-resistant aluminate cement in Examples 1 - 5 above, and test its compressive strength, initial seepage pressure, and permeability coefficient according to the above measurement steps and measurement standards. The test results are averaged and recorded in the following table.

[0115] Table: Performance test results of compressive strength, initial seepage pressure, and permeability coefficient in Examples 1 - 5

[0116]

[0117] As can be seen from the above table, during the preparation process of the high-strength and high-permeability-resistant aluminate cement in Examples 1 - 5, it has a good effect of improving the production effect of the high-strength and high-permeability-resistant aluminate cement. Bauxite provides the aluminum source and forms aluminate minerals, which is the main source of the cement strength. Modified forsterite promotes the formation of magnesium aluminate spinel, enhancing the high-temperature resistance and mechanical strength of the cement. Aluminum borate is used as a flux to lower the calcination temperature, promote mineral formation, induce crystal nucleus generation, and optimize the microscopic structure of the cement. Limestone adjusts the setting time of the cement, reacts with bauxite to form calcium aluminate, increasing the early strength. Gypsum delays the hydration rate of the cement, prevents flash setting, generates ettringite, and improves the early strength. Titanium dioxide photocatalytically decomposes harmful substances, enhances the impermeability, refines the pores of the cement, and increases the density. Lithium carbonate inhibits the polymorphic transformation of aluminate minerals, reduces volume shrinkage, and enhances the durability and crack resistance of the cement. Silica fume fills the pores of the cement, increases the density, and the pozzolanic reaction generates C-S-H gel, enhancing the strength and impermeability; thus achieving the purpose of improving the production effect of the high-strength and high-permeability-resistant aluminate cement;

[0118] Its compressive strength is 51.9 - 54.6 MPa, which is regarded as high strength; the initial seepage pressure is 1.27 - 1.62 MPa, and the permeability coefficient is 0.74 - 0.88×10 -10 cm / s, which is regarded as having strong impermeability;

[0119] It can be seen that when the production raw materials are fixed, the production effect of high-strength and high-permeability-resistant aluminate cement can be increased by adjusting the proportion of the preparation raw materials. Combining the data in the above table, it is not difficult to see that when preparing high-strength and high-permeability-resistant aluminate cement, the high-strength and high-permeability-resistant aluminate cement prepared with 48 parts of bauxite, 15 parts of modified forsterite, 5 parts of aluminum borate, 13 parts of limestone, 9 parts of gypsum, 4 parts of titanium dioxide, 3 parts of lithium carbonate, and 3 parts of silica fume has the highest strength. Analyzing the reason, the increase in the proportion of modified forsterite promotes the formation of magnesium aluminate spinel. This mineral has high strength and high-temperature resistance characteristics, significantly enhancing the mechanical properties of the cement. Aluminum borate, as a flux, reduces the calcination temperature, promotes the full formation of aluminate minerals, improves the mineral crystallinity, induces crystal nucleus generation, refines the microscopic structure of the cement, reduces pore defects, and enhances the strength. It is obtained from Examples 1-5.

[0120] It can be seen that when the production raw materials are fixed, the production effect of high-strength and high-permeability-resistant aluminate cement can be increased by adjusting the proportion of the preparation raw materials. Combining the data in the above table, it is not difficult to see that when preparing high-strength and high-permeability-resistant aluminate cement, the high-strength and high-permeability-resistant aluminate cement prepared with 55 parts of bauxite, 10 parts of modified forsterite, 4 parts of aluminum borate, 12 parts of limestone, 8 parts of gypsum, 6 parts of titanium dioxide, 2 parts of lithium carbonate, and 3 parts of silica fume has the highest impermeability. Analyzing the reason, the highest proportion of bauxite generates more aluminate minerals, forming a continuous gelling structure, reducing connected pores, and improving impermeability. The increase in the proportion of titanium dioxide leads to the decomposition of harmful substances by photocatalysis, inhibits the penetration of erosive media in the pores, refines the pore structure, reduces the porosity, enhances the cement density, reduces the inhibition of the crystal form transformation of aluminate minerals, makes the structure more stable, reduces the volume shrinkage cracks in the later stage, and indirectly improves the impermeability. It is obtained from Examples 1-5.

[0121] Examples 6-13

[0122] A kind of high-strength and high-permeability-resistant aluminate cement, and the corresponding relationship of its used preparation method is shown in the following table.

[0123] Table: Comparison table of the usage of high-strength and high-permeability-resistant aluminate cement in Examples 6-15

[0124] Group High-strength and high impermeability aluminate cement Example 6 Prepared from Preparation Example 6 Example 7 Prepared from Preparation Example 7 Example 8 Prepared from Preparation Example 8 Example 9 Prepared from Preparation Example 9 Example 10 Prepared from Preparation Example 10 Example 11 Prepared from Preparation Example 11 Example 12 Prepared from Preparation Example 12 Example 13 Prepared from Preparation Example 3

[0125] Extract the high-strength and high-permeability-resistant aluminate cement in Examples 6-13 above, and test its compressive strength, initial water seepage pressure, and permeability coefficient according to the above measurement steps and measurement standards. The test results are averaged and recorded in the following table.

[0126] Table: Performance test results of compressive strength, initial water seepage pressure, and permeability coefficient of Examples 1, 6-13

[0127]

[0128]

[0129] As can be seen from the above table, in the preparation process of the high-strength and high-permeability-resistant aluminate cement in Examples 1 and 6-11, it has a good effect of improving the production effect of the high-strength and high-permeability-resistant aluminate cement. Bauxite provides the aluminum source to form aluminate minerals, which is the main source of the cement strength. Modified forsterite promotes the formation of magnesium aluminate spinel, enhancing the high-temperature resistance and mechanical strength of the cement. Aluminum borate acts as a flux to reduce the calcination temperature, promote mineral formation, induce crystal nucleus generation, and optimize the microscopic structure of the cement. Limestone adjusts the setting time of the cement, reacts with bauxite to form calcium aluminate, increasing the early strength. Gypsum delays the hydration rate of the cement, prevents flash setting, forms ettringite, and improves the early strength. Titanium dioxide photocatalytically decomposes harmful substances, improves the impermeability, refines the pores of the cement, and enhances the density. Lithium carbonate inhibits the polymorphic transformation of aluminate minerals, reduces volume shrinkage, and enhances the durability and crack resistance of the cement. Silica fume fills the pores of the cement, improves the density, and forms C-S-H gel through pozzolanic reaction, enhancing the strength and impermeability; thus achieving the purpose of improving the production effect of the high-strength and high-permeability-resistant aluminate cement;

[0130] Its compressive strength is 51.9-52.7 MPa, which is regarded as high strength; the initial seepage pressure is 1.32-1.37 MPa, and the permeability coefficient is 0.82-0.88×10 -10 cm / s, which is regarded as strong impermeability;

[0131] It can be seen that when the production raw materials are certain, the production effect of the high-strength and high-permeability-resistant aluminate cement can be increased by adjusting the preparation conditions. Combining the data in the above table, it is not difficult to see that when preparing bauxite, the surface-activated bauxite ore is mixed with 10% dilute hydrochloric acid solution at a liquid-solid ratio of 3:1; when preparing modified forsterite, the calcined product is wet-ground under the condition of a ball-to-material ratio of 5:1; when preparing the mineralization precursor solution, the surface-modified calcium carbonate template agent is mixed with 0.1 mol / L Ca(NO3)2 solution at a volume ratio of 1:3; when preparing the cement clinker, the cement clinker is mixed with the mineralization precursor solution at a volume ratio of 1:3; the obtained high-strength and high-permeability-resistant aluminate cement has the highest strength, which is obtained from Examples 1 and 6-13.

[0132] This specific embodiment is only an explanation of the present invention and not a limitation thereof. Those skilled in the art can make modifications without creative contributions to this embodiment after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A preparation method of high-strength and high impermeability aluminate cement, characterized in that, It includes the following steps: C1. Select super-grade bauxite ore with Al2O3 content ≥ 85%. After being coarsely crushed by a jaw crusher to a particle size < 5 mm, the bauxite powder is subjected to surface activation treatment with 10% dilute hydrochloric acid solution, then dehydrated and dried at 120 °C for 2 h to obtain bauxite; C2. Grind the raw forsterite ore to 200 meshes, then place it in a high-temperature tubular furnace and calcine it at 1500 °C for 2 h under N2 atmosphere. After the calcined product is quenched and rapidly cooled with water, it is wet-ground for 4 h by adding 0.5% sodium polyacrylate dispersant through a planetary ball mill to obtain modified forsterite; C3. Extract calcium carbonate template agent from deep-sea corals. After removing the organic matrix by dissolving with dilute acetic acid, porous CaCO3 microspheres with a particle size of 20 - 50 nm are prepared by spray drying method. The microspheres are dispersed in deionized water to prepare a suspension with a solid content of 15%. 0.3% chitosan is added for surface modification, then it is mixed with 0.1 mol / L Ca(NO3)2 solution, 0.05% polyvinyl alcohol is added as a film-forming agent, the pH is adjusted to 9.0 with ammonia water, and it is stirred in a constant temperature water bath at 60 °C for 30 min to obtain a mineralization precursor solution. C4. Put bauxite, modified forsterite, aluminum borate, limestone, gypsum, titanium dioxide, lithium carbonate, and silica fume into a mixer and mix at a speed of 45 r / min for 40 min to make a uniform raw meal. Press the raw meal into a cylindrical green body with a size of φ50×20 mm and place it in a graphite crucible of a plasma reaction furnace. During this period, introduce argon with a flow rate of 50 L / min and maintain the pressure in the furnace at 5×10 -3 Pa. Start the radio frequency power supply and gradually increase the power to 80 kW to raise the temperature in the furnace to 1200 °C within 30 min and maintain the constant temperature reaction for 2 h. After the reaction is completed, immediately introduce liquid nitrogen into the furnace and perform rapid quenching under the condition of a cooling rate of 500 °C / min. The quenched clinker is crushed to 10 mm by a jaw crusher and then classified to a particle size of 3-5 mm through a vibrating screen to obtain cement clinker; C5. Immerse the cement clinker obtained in C4 into the mineralization precursor solution obtained in C3, at a rotation speed of 150 r / min, a temperature of 45 °C, and cure for 72 h. During this period, 10% volume of the mineralization precursor solution is replenished every 12 h. The cured particles are washed 3 times with deionized water, then immersed in an ethanol solution containing 5% silane coupling agent for 2 h, taken out and dried in a forced-air drying oven at 80 °C for 12 h to obtain the modified cement clinker; C6. Place the modified cement clinker obtained in C5 into a tube mill and conduct rough grinding under the conditions of a feeding rate of 15 t / h, an inlet and outlet pressure difference of 0.08 MPa, a ventilation volume of 2000 m 3 / h, and a specific surface area of the milled material of 300 m 2 / kg. Then mix the roughly ground material with 2% TiO2 and 3% lithium-based admixture and feed them into a vertical roller mill. Conduct fine grinding under the conditions of a roll pressure of 8 MPa, a grinding table speed of 35 r / min, and a specific surface area of 380 - 420 m 2 / kg to obtain high-strength and high impermeability aluminate cement.

2. The preparation method of a high-strength and high impermeability aluminate cement according to claim 1, wherein: The components and weight parts of the raw materials for preparing the high-strength and high-permeability resistance aluminate cement are as follows: 48 - 55 parts of bauxite, 10 - 15 parts of modified forsterite, 3 - 5 parts of aluminum borate, 12 - 15 parts of limestone, 8 - 10 parts of gypsum, 4 - 6 parts of titanium dioxide, 2 - 3 parts of lithium carbonate, 2 - 3 parts of silica fume.

3. The preparation method of a high-strength and high-permeability-resistant aluminate cement according to claim 1, wherein: In the surface activation treatment in C1, the bauxite ore and 10% dilute hydrochloric acid solution are mixed at a liquid-solid ratio of (2 - 4):

1.

4. The preparation method of a high-strength and high impermeability aluminate cement according to claim 1, characterized in that: In C2, the wet grinding of the calcined product is carried out under the condition of a ball-to-material ratio of (4 - 6):

1.

5. The preparation method of a high-strength and high-permeability-resistant aluminate cement according to claim 1, characterized in that: In C3, the surface-modified calcium carbonate template agent suspension and 0.1 mol / L Ca(NO3)2 solution are mixed at a volume ratio of 1:(2 - 4).

6. The preparation method of a high-strength and high anti-seepage aluminate cement according to claim 1, characterized in that: In C5, the cement clinker is immersed in the mineralization precursor solution under the condition of a liquid-solid ratio of 5:

1.

7. The high-strength and high-permeability resistance aluminate cement prepared by the preparation method according to any one of claims 1 - 6.

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