High-temperature sintered high-calcium sulphoaluminate red mud-based grouting material and its preparation method and application

Abstract

The present invention discloses a high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material, as well as its preparation method and application. The raw materials for the cement clinker include: 40-50 parts red mud, 20-25 parts phosphogypsum, 10-15 parts coal gangue, 15-20 parts bauxite, and 5-10 parts carbide slag. The slurry ingredients are: 1400-1600 parts high-calcium sulphoaluminate cement clinker, 600-800 parts shield sand, 100-200 parts steel slag, and 50-60 parts bentonite. The present invention utilizes a three-heating and three-holding process, heating to 260-300°C, 760-820°C, and 1100-1250°C, respectively, and holding for 30 minutes, 30 minutes, and 2 hours, respectively. This heating and holding process dehydrates and combines CaO, Al2O3, and CaSO4 in the raw materials during the high-temperature sintering process, increasing the content of minerals such as #imgabs0#C4AF in the clinker while controlling the C2S content. This improves the clinker's rapid hardening and high-strength properties. Ultrafine ball milling technology is used to control the powder particle size ranges to 0-4, 4-8, and 10-22 μm, with a mass ratio of 9:3:1 between the three ranges. This results in the grouting material exhibiting early strength, rapid hardening, and corrosion resistance.

Description

Technical Field

[0001] The invention herein relates to the field of preparing grouting materials using sulphoaluminate cement, in particular to the preparation and application of a high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material. Background Art

[0002] As a major alumina producer, China discharges millions of tons of waste slag annually. Red mud is an industrial waste residue generated during alumina production, with 1.0 to 1.8 tons of red mud discharged for every ton of alumina produced. As red mud stockpiles grow and the environmental pollution it causes becomes increasingly serious, its current utilization rate is low, with my country's comprehensive red mud utilization rate at only 7%. Red mud is highly alkaline, and some parts are radioactive. Its storage severely impacts the ecological balance and poses a significant threat to human health. Maximizing red mud resource utilization is imperative. Its use in grouting materials can not only alleviate the environmental burden and increase economic benefits, but also improve the erosion resistance, frost resistance, and anti-seepage properties of the grouting material.

[0003] Sulphoaluminate cement is primarily composed of calcium sulfoaluminate, dicalcium silicate, and iron. Its production requires calcium sulfate as a raw material with a high aluminum-silicon ratio. Limestone, bauxite, and gypsum are typically used, and the sintering temperature is 1250-1350°C. The calcium, aluminum, sulfur, and silicon in these raw materials are sintered at high temperatures to produce calcium sulfoaluminate and dicalcium silicate, which are then made into sulphoaluminate cement clinker. High-calcium sulphoaluminate cement contains a higher calcium content than ordinary sulphoaluminate cement. Using red mud and phosphogypsum as the primary raw materials, supplemented by other raw materials, and sintering at high temperatures, sulphoaluminate cement clinker, primarily composed of calcium sulfoaluminate, dicalcium silicate, and iron, can be produced. This method achieves comprehensive utilization of difficult-to-use solid waste, and its application has been very successful. This represents an innovation for the cement industry, but the high firing temperatures produce large amounts of pollutants such as CO2, which pose a significant environmental risk.

[0004] Portland cement has stable properties, but its early strength development is slow and it is easily damaged by seawater corrosion, which cannot guarantee the durability of marine engineering. High-calcium sulphoaluminate cement not only has the excellent properties of traditional Portland cement, but also has the excellent properties of rapid hardening and early strength, dense cement stone structure, good anti-seepage and corrosion resistance, low CaO concentration in the cement liquid phase, and hydration products with filling and densification effects.

[0005] Applying sulphoaluminate cement clinker in grouting materials can not only solve the problems of low strength and poor corrosion resistance of ordinary grouting materials, but also make the slurry have the properties of early strength, high strength, frost resistance, impermeability, and resistance to seawater erosion, which can make its application environment more extensive and has very good development prospects. Summary of the Invention

[0006] In response to the problems caused by the above situation, the present application provides a high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material and its preparation method and application. In this application, a new sintering process of three heatings (260-300°C, 760-820°C, 1100-1250°C) and three insulations (30min, 30min, 2h) is adopted, which can effectively increase the cementitious minerals in the clinker, and the low-temperature firing can reduce carbon emissions. High-calcium raw materials such as red mud and phosphogypsum are selected to make high-calcium sulphoaluminate cement. In addition to the excellent properties of traditional silicate cement, it also has the characteristics of fast hydration and hardening of sulphoaluminate cement and high early strength. Adjusting and selecting a new particle size and ratio range can make the slurry have the characteristics of high strength and high stone rate. Effectively utilizing solid wastes such as red mud, steel slag, phosphogypsum, coal gangue, carbide slag as raw materials has low production cost and good economic benefits.

[0007] To achieve the above object, the technical solution adopted in the present invention is as follows:

[0008] A high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material, a preparation method, and an application thereof. The high-calcium sulphoaluminate cement clinker in the grouting material comprises the following components in parts by weight:

[0009]

[0010] The obtained high calcium sulphoaluminate cement clinker is then used in grouting materials, which include the following components in parts by weight:

[0011]

[0012] Preferably, the sintering process is to heat the raw material three times and keep it warm three times, heating to 260-300℃, 760-820℃, 1100-1250℃ respectively, and keeping it warm for 30min, 30min, and 2h respectively, which is conducive to the full combination of calcium, aluminum, and sulfur ions in the raw material and improve the clinker content. The content of C4AF controls the content of C2S.

[0013] Preferably, the raw materials are pre-prepared by grinding all raw materials uniformly to a size that can pass a 170-mesh sieve. This ensures uniform and small particle size of the raw materials. Mineralizers are added during the sintering of the sulphoaluminate clinker to improve the flammability of the material and reduce the sintering temperature.

[0014] Preferably, the mineralizer is a composite mineralizer, including CaSO4 and CaF2, which can not only reduce the concentration of sulphoaluminate

[0015] The temperature of salt cement sintering can also provide synthetic of sulfur element.

[0016] Preferably, the water-cement ratio is controlled between 0.65 and 0.80, the mortar-sand ratio is controlled between 0.5 and 0.6, and the water expansion ratio is controlled within 0.2.

[0017] Preferably, the sulfur element in the clinker is provided by phosphogypsum and mineralizer, the calcium element in the clinker is provided by carbide slag and phosphogypsum, the aluminum element in the clinker is provided by red mud, bauxite and coal gangue, and the silicon element in the clinker is provided by red mud and coal gangue.

[0018] Preferably, the calcium content of the selected materials is relatively high, and the high calcium sulphoaluminate cement is cooked

[0019] In the material The higher the content, the faster the hydration reaction.

[0020] Preferably, the red mud particles have relatively uniform fineness, high surface energy and reaction activity, the SiO2 and CaO contents in the red mud are much higher than those in the Bayer process red mud, and the red mud has high activity and good hydration performance.

[0021] Furthermore, the red mud selected is sintered red mud, which has much higher performance than other types of red mud.

[0022] Furthermore, the gases generated during the firing process are collected and classified. CO2 can carbonize the steel slag, significantly improving its compressive strength.

[0023] Preferably, the particle size of sulphoaluminate cement clinker is 2-8 μm and 10-22 μm, with a mass ratio of 3:7. In the fine particle size range of 2-8 μm, the hydration degree is high and the 3d strength is high; in the range of 8-24 μm, the water demand and hydration rate of sulphoaluminate cement clinker are relatively moderate, and it has a higher 3d strength and the highest 28d strength.

[0024] Preferably, phosphogypsum is a solid waste generated in the wet phosphoric acid process, and its main component is dihydrate gypsum, which can replace natural gypsum as a raw material for preparing sulfoaluminate cement. The impurities in the phosphogypsum can serve as mineralizers to promote the formation of cement clinker minerals, and the calcium oxide produced by the decomposition of the phosphogypsum can replace part of the limestone.

[0025] Preferably, coal gangue is solid waste discharged during coal mining and coal washing. It is a low-carbon rock associated with coal during the coal formation period. It contains a large amount of SiO2, Al2O3 and other substances. As a raw material for preparing sulphoaluminate cement, it can improve the fluidity of concrete and obtain high-performance concrete with strong fluidity and strength.

[0026] Preferably, the bauxite is from Henan Province, where the aluminum content is 47.37% and W(Al2O3) / W(SiO2)=1.7. According to the bauxite industry index requirements, the aluminum content of bauxite should be ≥40% and W(Al2O3) / W(SiO2)≥1.8. Therefore, this bauxite is a low-aluminum-silicon ratio, low-grade bauxite.

[0027] Preferably, the main chemical component of carbide slag is CaO (calculated as oxide), with a content of 54% to 72%, and contains small amounts of impurities such as SiO2, Al2O3, SO3, and Fe2O3, with a loss on ignition of 23% to 31%. Carbide slag has a relatively fine particle size and high activity, meeting the requirements of building material preparation and environmental protection.

[0028] Preferably, as an improved technical solution of the present invention, the shield sand is derived from the slag produced during the shield excavation process. The shield sand produced after separation has a suitable particle size and good economic benefits.

[0029] Preferably, after carbonization, the porosity of the steel slag is reduced and the compressive strength is significantly improved.

[0030] Preferably, the main component of bentonite is sodium montmorillonite, which is a mineral composed of a microscopic flaky structure; the flaky crystals are usually less than 2 μm and are colloidal. They can absorb water molecules, thereby increasing the molecular distance and expanding the bentonite particles. Once the bentonite particles absorb water, the intramolecular charge reaches saturation, which prevents water molecules from passing through. This ensures that the bentonite has extremely low water permeability, giving it an excellent waterproof barrier effect.

[0031] Preferably, additional admixtures such as early strength agent, water reducing agent, etc. can be added according to different environments.

[0032] Furthermore, the present invention also provides a preparation process for the above-mentioned red mud for high-calcium sulphoaluminate cement slurry, which comprises: (1) placing 40-50 parts of red mud, 20-25 parts of phosphogypsum, 10-15 parts of coal gangue, 15-20 parts of bauxite, and 5-10 parts of carbide slag into a dryer and drying them at 105°C to 110°C for two hours to keep the quality of the raw materials unchanged.

[0033] (2) taking the product of (1) and grinding it in a grinder, while controlling the grinding temperature below 80° C. during the process, and sieving it through a 170-mesh sieve after grinding to obtain powder 1;

[0034] (3) placing the product powder in step (2) in a calcining furnace, adding 1 to 2 parts of a mineralizer, and first heating to 260 to 300° C. and keeping the temperature for 30 minutes, then continuing to heat to 760 to 820° C. and keeping the temperature for 30 minutes, and finally heating to 1100 to 1250° C. and keeping the temperature for two hours to obtain high-calcium sulphoaluminate cement clinker during a high-temperature sintering process.

[0035] (4) Ball milling the cement clinker to a maximum particle size of less than 60 μm.

[0036] (5) The steel slag specimens were subjected to carbonization treatment in the early stage. The carbon dioxide used for carbonization came from the industrial waste gas collected during the burning of high calcium sulphoaluminate cement clinker.

[0037] (6) The raw materials, shield sand, bentonite and carbonized steel slag, are crushed separately, and then ball-milled to a maximum particle size of less than 60 μm. They are weighed in proportion and set aside.

[0038] (7) Put bentonite and shield sand into a mixer and stir them at a stirring speed of 800 to 1000 r / min for 10 to 15 minutes to make them uniform; put steel slag into a mixer and stir them at a stirring speed of 800 to 1000 r / min for 5 to 8 minutes.

[0039] (8) The raw materials in (7) and high calcium sulphoaluminate cement clinker are subjected to ultrafine ball milling, so that the particle size of the high calcium sulphoaluminate cement clinker is 2 to 8 μm and 10 to 22 μm, and the mass ratio is 3:7; and the particle size of the steel slag is 4 to 8 μm.

[0040] (9) The bentonite and shield sand mixture in (8) is subjected to ultrafine ball milling to obtain particle sizes of 0-4 μm and 4-8 μm, with a mass ratio of 1:1.

[0041] (10) The product after ultrafine ball milling is placed in a blender and mixed thoroughly. 3 / 4 of water is added and stirred at a stirring speed of 1200-1300 r / min for 2-3 minutes to ensure that it is fully mixed.

[0042] (11) Add admixtures and 1 / 4 of water according to specific conditions, and stir at a stirring speed of 1200-1300 r / min for 2 minutes to obtain a high-calcium sulfoaluminate red mud-based grouting material.

[0043] Preferably, since the high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material has the characteristics of early strength, high strength, good reinforcement effect, and corrosion resistance, it can be used in harsh projects such as submarine engineering grouting and shield wall back grouting.

[0044] The beneficial effects of the present invention are:

[0045] 1. The present invention adopts a high-temperature sintering method to produce high-calcium sulphoaluminate cement clinker. After the raw materials are dried, they are fired. During the firing process, they are heated three times. First, they are heated to 260-300°C and kept warm for 30 minutes to remove the crystal water and interlayer water in the raw materials. Then they are heated to 760-820°C and kept warm for 30 minutes to allow the carbonates in the raw materials to fully react to generate oxidation products, in preparation for the subsequent solid-phase reaction. Finally, the temperature is heated to 1100-1250°C and kept warm for two hours, which is conducive to promoting the conversion of calcium ions, sulfur ions, aluminum ions, etc. in the raw materials to The synthetic conversion of C4AF, and at this time the temperature can effectively control the generation of C2S. C4AF hydration has the characteristics of fast reaction speed and high strength. C4AF produces more hydrated calcium sulfoaluminate, hydrated alumina gel, and iron gel, effectively enhancing the early strength and rapid hardening properties of the slurry. Currently, sulphoaluminate cement is sintered at 1250-1350°C using limestone, bauxite, and gypsum as raw materials. However, by adjusting the ratio of the raw materials, controlling the particle size, and adding admixtures, the calcination temperature of sulphoaluminate cement can be lowered to 1100-1250°C, reducing carbon emissions and allowing the hydration process to fully function.

[0046] 2. When selecting materials, there are many restrictions on the preparation of sulphoaluminate cement, which requires calcium sulfate and the aluminum-silicon ratio in the raw materials should be as high as possible. The main raw material is red mud, which is similar to the raw materials for sintering sulphoaluminate cement and has the possibility of replacing raw materials to make cement. The comprehensive utilization rate of red mud in my country is currently only 15%. In the present invention, red mud is introduced as a raw material, and the mass of red mud used accounts for as high as 35% to 40% of the total mass ratio, which can well realize the resource recycling of red mud and meet the preparation requirements of sulphoaluminate cement clinker. In addition, red mud cooperates with steel slag, coal gangue, and carbide slag to prepare sulphoaluminate cement clinker. The main components of the raw materials are rich in calcium, sulfur, aluminum, silicon, etc., and have a high aluminum-silicon ratio and calcium content. During the high-temperature sintering process, CaO, Al2O3, CaSO4, etc. in the raw materials,

[0047] After dehydration, it decomposes and combines to form new gelled minerals C4AF makes its clinker have the characteristics of early strength and high strength. And because the sulphoaluminate cement clinker is high calcium, the calcium content is higher than that of ordinary sulphoaluminate cement clinker when the raw materials are selected, the high calcium sulphoaluminate cement produced by its burning produces more hydration.

[0048] product C4AF.

[0049] 3. In order to bring out the best activity of each raw material, the present invention has made adjustments in the selection of particle size. In the current production process of most slurries, there is a lack of selection and control of the raw material particle size, which makes it difficult to give full play to the activity and hydration of the raw materials. The present invention has achieved specific optimization and classification in terms of particle size. The particle size of sulphoaluminate cement clinker is 2-8μm and 10-22μm, the water demand and hydration rate are relatively moderate, and a small amount of hydration products in the early stage can make the slurry structure more compact, with higher 3d and 28d strength. The steel slag particle size is adjusted to 4-8μm, with higher 3d and 28d activity indexes. Compared with materials with other particle sizes, the adjusted material has higher 3d and 28d strengths, suitable setting time, and is suitable for configuring setting materials.

[0050] 4. If the material is well stacked, it can form a higher strength without being fully hydrated. However, the slurry preparation in existing patents ignores this point. Most of them grind the raw materials into ordinary particle sizes, with obvious gaps between the particles, resulting in low strength. In order to increase the packing density of the slurry, reduce the initial porosity of the cement slurry, and improve the slurry strength, the present invention optimizes the mass proportion of each particle size range. After the raw materials are ultrafine ground, the high calcium sulphoaluminate cement clinker with a particle size of 2-8μm and 10-22μm is mixed with an air flow classifier at different speeds at a mass ratio of 3:7; the bentonite and shield sand mixture is ultrafine ball milled to a particle size of 0-4μm and 4-8μm, with a mass ratio of 1:1. This makes the slurry more compact and densely distributed internally, and has higher 3d and 28d strength after grouting.

[0051] 5. This invention captures carbon dioxide gas from high-temperature sintering of cement clinker and uses it to perform early carbonization treatment on steel slag specimens, effectively improving the compressive strength of the slag and reducing porosity. This also enhances the late-stage strength of the slurry and reduces bleeding. This not only addresses the issue of gas emissions during cement sintering, but also contributes to achieving dual carbon goals and protecting the ecological environment. Compared to conventional grouting slurries, this method also offers superior late-stage strength and bleeding rates.

[0052] 6. In addition to adding bentonite to improve the performance of the slurry, the present invention also has a unique flow effect that can improve the flow properties of the fast-hardening synchronous grouting material to a certain extent, enhance pumpability, and reduce the slurry bleeding rate. Additional admixtures can also be added according to different environments. For example, in a water-rich environment, the slurry is required to have characteristics such as early strength and rapid setting, which are difficult to meet with ordinary grouting materials. However, adding appropriate additives such as early strength agents, water reducers such as naphthalene-based high-efficiency water reducers, high-performance polycarboxylic acid water reducers, polycarboxylic acid-based high-efficiency water reducers, sodium chloride, sodium sulfate, etc. can well control its setting time, bleeding rate, and consistency. Mineralizers are also added during the calcination process to reduce the calcination temperature of sulphoaluminate cement and reduce carbon emissions. As a grouting material, it has good properties such as good pumpability, high early and late strength, strong durability, reasonable cost, environmental protection and non-toxicity, and good corrosion resistance, filling the gap in marine engineering grouting materials.

[0053] 7. The raw materials used in this invention, such as red mud, coal gangue, and carbide slag, are derived from industrial waste. The shield sand is separated from the shield slag during shield tunneling. Experimental results show that shield sand has similar properties to ordinary sand and is less expensive. The resulting high-calcium sulphoaluminate red mud-based grouting material exhibits excellent workability and can be grouted with additives tailored to the complexity of the site. It is primarily suitable for projects such as submarine tunnel grouting, shield grouting, and grouting in broken rock masses. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 The invention discloses a method for preparing a high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material. DETAILED DESCRIPTION

[0055] The following examples will clearly and completely demonstrate the concept, purpose, technical solution, and effects of the present invention. The following examples and accompanying drawings will help you fully understand the purpose, features, and effects of the present invention. Obviously, the examples described are only some examples of the present invention and are representative and can serve to illustrate this application to a certain extent.

[0056] Figure 1 The preparation method of the high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material of the present invention is described in conjunction with examples.

[0057] Example 1: High-temperature sintered high-calcium sulphoaluminate red mud-based grouting material for shield grouting in water-rich soft soil strata

[0058] 1. Prepare raw materials: red mud, phosphogypsum, coal gangue, bauxite, carbide slag, mineralizer, steel slag, bentonite, shield sand, water reducer, and early strength agent.

[0059] 2. Production steps

[0060] (1) Place 40 parts of red mud, 20 parts of phosphogypsum, 10 parts of coal gangue, 15 parts of bauxite, and 10 parts of carbide slag in a dryer and dry them at 105-110°C for two hours to keep the quality of the raw materials unchanged.

[0061] (2) taking the product of (1) and grinding it in a grinder, while controlling the grinding temperature below 80° C. during the process, and sieving it through a 170-mesh sieve after grinding to obtain powder 1;

[0062] (3) placing the product powder in step (2) in a calcining furnace, adding 2 parts of a mineralizer, and in a high-temperature sintering process, first heating to 260-300° C. and keeping the temperature for 30 minutes, then continuing to heat to 760-820° C. and keeping the temperature for 30 minutes, and finally heating to 1100-1250° C. and keeping the temperature for two hours to obtain high-calcium sulphoaluminate cement clinker.

[0063] (4) Ball milling the cement clinker to a maximum particle size of less than 60 μm.

[0064] (5) Prepare high calcium sulphoaluminate cement grouting slurry, the raw materials of which are: 1400 parts of high calcium sulphoaluminate cement clinker, 600 parts of shield sand, 100 parts of steel slag, 50 parts of bentonite, 1600 parts of water, 8 parts of water reducer, and 6 parts of early strength agent, wherein the early strength agent is a mixture of triethanolamine, sodium chloride, and calcium formate, and the mass ratio is 1:1.2:0.8; the water reducer is an ordinary naphthalenesulfonate type water reducer, and its water reduction rate is not less than 25%, the hydration control time is greater than 20h, and the hydrolysis degree is not higher than 30%.

[0065] (6) The steel slag specimens were subjected to an early carbonization treatment, and the carbon dioxide used for carbonization came from the industrial waste gas collected during the firing of high-calcium sulphoaluminate cement clinker.

[0066] (7) The bentonite, shield sand and carbonized steel slag in (5) are crushed separately, and then ball-milled to a maximum particle size of less than 60 μm. The mixture is weighed in proportion and set aside.

[0067] (8) Place bentonite and shield sand in a mixer and stir them at a stirring speed of 800-1000 r / min for 10-15 minutes to make them uniform; place steel slag in a mixer and stir them at a stirring speed of 800-1000 r / min for 5-8 minutes.

[0068] (9) The raw materials in (7) and high calcium sulphoaluminate cement clinker are subjected to ultrafine ball milling, so that the particle size of the high calcium sulphoaluminate cement clinker is 2 to 8 and 10 to 22 μm, and the mass ratio is 3:7; and the particle size of the steel slag is 4 to 8 μm.

[0069] (10) The bentonite and shield sand mixture in (8) is subjected to ultrafine ball milling to obtain a particle size range of 0-4 and 4-8 μm, with a mass ratio of 1:1.

[0070] (11) The product after ultrafine ball milling was placed in a blender and mixed thoroughly. 3 / 4 of water was added and stirred at a stirring speed of 1200-1300 r / min for 2-3 min.

[0071] (12) Add an early strength agent, a water reducing agent, and 1 / 4 of water, and stir at a stirring speed of 1200-1300 r / min for 2-3 minutes to obtain a red mud-based high-calcium sulfoaluminate cement-based grouting slurry for shield tunneling in water-rich strata.

[0072] Example 2: High-temperature sintered high-calcium sulphoaluminate red mud-based grouting material used for grouting treatment of water-rich broken rock mass

[0073] 1. Prepare raw materials: red mud, phosphogypsum, coal gangue, bauxite, carbide slag, mineralizer, steel slag, bentonite, shield sand, lignin, and early strength agent.

[0074] 2. Production steps

[0075] (1) 45 parts of red mud, 23 parts of phosphogypsum, 15 parts of coal gangue, 18 parts of bauxite, and 6 parts of carbide slag were placed in a dryer and dried at 105-110°C for two hours to keep the quality of the raw materials unchanged.

[0076] (2) taking the product of (1) and grinding it in a grinder, while controlling the grinding temperature below 80° C. during the process, and sieving it through a 170-mesh sieve after grinding to obtain powder 1;

[0077] (3) placing the product powder in step (2) in a calcining furnace, adding 2 parts of a mineralizer, and in a high-temperature sintering process, first heating to 260-300° C. and keeping the temperature for 30 minutes, then continuing to heat to 760-820° C. and keeping the temperature for 30 minutes, and finally heating to 1100-1250° C. and keeping the temperature for two hours to obtain high-calcium sulphoaluminate cement clinker.

[0078] (4) Ball milling the cement clinker to a maximum particle size of less than 60 μm.

[0079] (5) Prepare high calcium sulphoaluminate cement grouting slurry, the raw materials of which are: 1500 parts of high calcium sulphoaluminate cement clinker, 650 parts of shield sand, 150 parts of steel slag, 55 parts of bentonite, 1800 parts of water, 6 parts of early strength agent, and 7 parts of lignin, wherein the early strength agent is a mixture of triethanolamine, sodium chloride, and calcium formate, and the mass ratio is 1:1.2:0.8.

[0080] (6) The steel slag specimens were subjected to an early carbonization treatment, and the carbon dioxide used for carbonization came from the industrial waste gas collected during the firing of high-calcium sulphoaluminate cement clinker.

[0081] (7) The bentonite, shield sand and carbonized steel slag in (5) are crushed separately, and then ball-milled to a maximum particle size of less than 60 μm. The mixture is weighed in proportion and set aside.

[0082] (8) Place bentonite and shield sand in a mixer and stir them at a stirring speed of 800-1000 r / min for 10-15 minutes to make them uniform; place steel slag in a mixer and stir them at a stirring speed of 800-1000 r / min for 5-8 minutes.

[0083] (9) The raw materials in (7) and high calcium sulphoaluminate cement clinker are subjected to ultrafine ball milling, so that the particle size of the high calcium sulphoaluminate cement clinker is 2 to 8 and 10 to 22 μm, and the mass ratio is 3:7; and the particle size of the steel slag is 4 to 8 μm.

[0084] (10) The bentonite and shield sand mixture in (8) is subjected to ultrafine ball milling to obtain a particle size range of 0-4 and 4-8 μm, with a mass ratio of 1:1.

[0085] (11) The product after ultrafine ball milling was placed in a blender and mixed thoroughly. 3 / 4 of water was added and stirred at a stirring speed of 1200-1300 r / min for 2-3 min.

[0086] (12) Adding an early strength agent, lignin, and 1 / 4 of water, stirring at a stirring speed of 1200-1300 r / min for 2-3 minutes, a red mud-based high-calcium sulphoaluminate cement-based grouting slurry for water-rich broken rock mass is obtained.

[0087] Example 3: High-temperature sintered high-calcium sulphoaluminate red mud-based grouting material for grouting in broken rock mass

[0088] 1. Prepare raw materials: red mud, phosphogypsum, coal gangue, bauxite, carbide slag, mineralizer, steel slag, bentonite, shield sand, natural fiber, and early strength agent.

[0089] 2. Production steps

[0090] (1) 50 parts of red mud, 25 parts of phosphogypsum, 15 parts of coal gangue, 20 parts of bauxite, and 8 parts of carbide slag were placed in a dryer and dried at 105-110°C for two hours to keep the quality of the raw materials unchanged.

[0091] (2) taking the product of (1) and grinding it in a grinder, while controlling the grinding temperature below 80° C. during the process, and sieving it through a 170-mesh sieve after grinding to obtain powder 1;

[0092] (3) placing the product powder in step (2) in a calcining furnace, adding 2 parts of a mineralizer, and in a high-temperature sintering process, first heating to 260-300° C. and keeping the temperature for 30 minutes, then continuing to heat to 760-820° C. and keeping the temperature for 30 minutes, and finally heating to 1100-1250° C. and keeping the temperature for two hours to obtain high-calcium sulphoaluminate cement clinker.

[0093] (4) Ball milling the cement clinker to a maximum particle size of less than 60 μm.

[0094] (5) Prepare high calcium sulphoaluminate cement grouting slurry. The raw materials are: 1600 parts of high calcium sulphoaluminate cement clinker, 700 parts of shield sand, 120 parts of steel slag, 60 parts of bentonite, 2000 parts of water, 6 parts of early strength agent, and 20 parts of natural fiber. The early strength agent is a mixture of triethanolamine, sodium chloride, and calcium formate in a mass ratio of 1:1.2:0.8.

[0095] (6) The steel slag specimens were subjected to an early carbonization treatment, and the carbon dioxide used for carbonization came from the industrial waste gas collected during the firing of high-calcium sulphoaluminate cement clinker.

[0096] (7) The bentonite, shield sand and carbonized steel slag in (5) are crushed separately, and then ball-milled to a maximum particle size of less than 60 μm. The mixture is weighed in proportion and set aside.

[0097] (8) Place bentonite and shield sand in a mixer and stir them at a stirring speed of 800-1000 r / min for 10-15 minutes to make them uniform; place steel slag in a mixer and stir them at a stirring speed of 800-1000 r / min for 5-8 minutes.

[0098] (9) The raw materials in (7) and high calcium sulphoaluminate cement clinker are subjected to ultrafine ball milling, so that the particle size of the high calcium sulphoaluminate cement clinker is 2 to 8 and 10 to 22 μm, and the mass ratio is 3:7; and the particle size of the steel slag is 4 to 8 μm.

[0099] (10) The bentonite and shield sand mixture in (8) is subjected to ultrafine ball milling to obtain particle sizes of 0-4 and 4-8 μm, respectively, with a mass ratio of 1:1.

[0100] (11) The product after ultrafine ball milling was placed in a blender and mixed thoroughly. 3 / 4 of water was added and stirred at a stirring speed of 1200-1300 r / min for 2-3 min.

[0101] (12) Adding an early strength agent, natural fiber, and 1 / 4 of water, stirring at a stirring speed of 1200-1300 r / min for 2-3 minutes, a red mud-based high-calcium sulfoaluminate cement-based grouting slurry for crushing rock mass is obtained.

[0102] Comparative group 1 Ordinary Portland cement-based grouting material used for shield grouting in water-rich strata

[0103] 1. Raw materials: ordinary Portland cement, steel slag, bentonite, shield sand, silica fume, water reducing agent, early strength agent.

[0104] 2. Production steps

[0105] (1) Carbonize the steel slag specimens in advance.

[0106] (2) The ordinary Portland cement, bentonite, shield sand and carbonized steel slag in the raw materials are crushed separately, and then ball-milled to a maximum particle size of less than 60 μm. The raw materials are weighed in proportion and set aside.

[0107] (3) Place bentonite and shield sand in a mixer and stir them at a stirring speed of 800-1000 r / min for 10-15 minutes to make them uniform; place steel slag in a mixer and stir them at a stirring speed of 800-1000 r / min for 5-8 minutes.

[0108] (4) The raw materials are subjected to ultrafine ball milling to make the particle size of ordinary silicate cement clinker 2-8 and 10-22 μm, with a mass ratio of 3:7; and the particle size of steel slag is 4-8 μm.

[0109] (5) The bentonite and shield sand mixture in (3) is subjected to ultrafine ball milling to obtain particle sizes of 0-4 and 4-8 μm, respectively, with a mass ratio of 1:1.

[0110] (6) The product after ultrafine ball milling was placed in a blender and mixed thoroughly, 3 / 4 of water was added, and the mixture was stirred at a stirring speed of 1200-1300 r / min until the product was finely divided into 2-3 μm.

[0111] (7) Add early strength agent, water reducing agent and 1 / 4 of water, stir at a stirring speed of 1200-1300 r / min for 2-3 minutes to obtain an ordinary silicate cement grouting slurry for shield tunneling in water-rich strata.

[0112] Comparative Group 2 Ordinary sulphoaluminate cement-based grouting material used for grouting treatment of water-rich broken rock mass

[0113] 1. Raw materials: ordinary sulphoaluminate cement, coal furnace slag, bentonite, shield sand, silica fume, lignin, early strength agent.

[0114] 2. Production steps (1) Crush the ordinary sulphoaluminate cement, coal furnace slag, bentonite and shield sand in the raw materials separately, then ball-mill them to a maximum particle size of less than 60 μm, weigh them according to proportion and set them aside.

[0115] (3) Place bentonite and shield sand in a mixer and stir them at a stirring speed of 800-1000 r / min for 10-15 minutes to make them uniform; place coal furnace slag and silica fume in a mixer and stir them at a stirring speed of 800-1000 r / min for 5-8 minutes.

[0116] (4) The raw materials are subjected to ultrafine ball milling to reduce the particle size of ordinary sulphoaluminate cement to 2-8 and 10-22 μm, respectively, with a mass ratio of 3:7; and the particle size of coal furnace slag and silica fume to 4-8 μm.

[0117] (5) The bentonite and shield sand mixture in (3) is subjected to ultrafine ball milling to make its particle size range 0-4 and 4-8 μm, and the mass ratio is 1:1.

[0118] (6) The product after ultrafine ball milling is placed in a blender and mixed thoroughly, 3 / 4 of water is added, and the mixture is stirred at a stirring speed of 1200-1300 r / min for 2-3 min.

[0119] (7) Add lignin, early strength agent, and 1 / 4 of water, and stir at a stirring speed of 1200-1300 r / min for 2-3 minutes to obtain a common sulphoaluminate cement slurry for water-rich broken rock mass.

[0120] Comparative group of high calcium silicate cement-based grouting materials used for grouting repair of broken rock

[0121] 1. Raw materials: high calcium silicate cement, fly ash, steel slag, slag, shield sand, silica fume, bentonite, natural fiber, early strength agent.

[0122] 2. Production steps (1) Crush the high calcium silicate cement, fly ash, steel slag, slag, shield sand, silica fume and bentonite in the raw materials separately, then ball mill them to a maximum particle size of less than 60 μm, weigh them according to proportion and set them aside.

[0123] (3) Place bentonite, shield sand and silica fume in a mixer and stir them at a stirring speed of 800-1000 r / min for 10-15 minutes to make them uniform; place fly ash, steel slag, slag and shield sand in a mixer and stir them at a stirring speed of 800-1000 r / min for 5-8 minutes.

[0124] (4) The raw materials are subjected to ultrafine ball milling to make the particle size of ordinary sulphoaluminate cement 2-8 and 10-22 μm, with a mass ratio of 3:7; and the particle size of fly ash, steel slag, slag and shield sand is 4-8 μm.

[0125] (5) The bentonite, shield sand, and silica fume mixture in (3) is subjected to ultrafine ball milling to obtain a particle size range of 0-4 and 4-8 μm, with a mass ratio of 1:1.

[0126] (6) The product after ultrafine ball milling is placed in a blender and mixed thoroughly, 3 / 4 of water is added, and the mixture is stirred at a stirring speed of 1200-1300 r / min for 2-3 minutes.

[0127] (7) Add natural fiber, early strength agent, and 1 / 4 of water, and stir at a stirring speed of 1200-1300 r / min for 2-3 minutes to obtain a high-calcium silicate cement-based grouting slurry for crushing rock mass.

[0128] Table 1

[0129]

[0130] It can be seen from the results in Table 1 that the slurries obtained in various embodiments of the present invention can effectively meet the general performance requirements of single-liquid grouting such as shield tunneling in water-rich strata and grouting in broken rock masses, and have a shorter setting time and higher early and late strength, which can better meet the needs of construction.

Claims

1. A high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material, characterized in that: The raw materials of the grouting material include the following parts by weight: 1400-1600 parts of high-temperature sintered high-calcium sulphoaluminate cement clinker, 600-800 parts of shield sand, 100-200 parts of steel slag, 50-60 parts of bentonite, and 1600-2000 parts of water; The raw materials of high-temperature sintered high-calcium sulphoaluminate cement clinker include the following parts by weight: 40-50 parts of red mud, 20-25 parts of phosphogypsum, 10-15 parts of coal gangue, 15-20 parts of bauxite, 5-10 parts of carbide slag, and 1-2 parts of mineralizer; After ball milling, the particle sizes of high-calcium sulphoaluminate cement clinker sintered at high temperature were 2-8 μm and 10-22 μm, the particle size of steel slag was 4-8 μm, and the particle size of shield sand-bentonite mixture was 0-4 μm and 4-8 μm. The sintering process of high-temperature sintered high-calcium sulphoaluminate cement clinker is as follows: first, heat to 260-300℃ and keep warm for 30min, then continue to heat to 760-820℃ and keep warm for 30min, and finally heat to 1100-1250℃ and keep warm for 2h, to increase the C4AF content, controls the C2S content in clinker; The preparation method of high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material comprises the following steps: (1) Place 40-50 parts of red mud, 20-25 parts of phosphogypsum, 10-15 parts of coal gangue, 15-20 parts of bauxite, and 5-10 parts of carbide slag in a dryer and dry at 105-110°C for two hours; (2) taking the product of (1) and grinding it in a grinder, while controlling the grinding temperature below 80° C. during the process, and sieving it through a 170-mesh sieve after grinding to obtain powder 1; (3) placing the product powder in step (2) in a calcining furnace, adding 1 to 2 parts of a mineralizer, and first heating to 260 to 300° C. and keeping the temperature for 30 minutes, then heating to 760 to 820° C. and keeping the temperature for 30 minutes, and finally heating to 1100 to 1250° C. and keeping the temperature for two hours to obtain high-temperature sintered high-calcium sulphoaluminate cement clinker; (4) ball-milling the cement clinker to a maximum particle size of less than 60 μm; (5) The steel slag specimens were subjected to carbonization treatment in the early stage. The carbon dioxide used for carbonization was collected from the industrial waste gas during the high-temperature sintering of high-calcium sulphoaluminate cement clinker. (6) Crush the shield sand, bentonite and carbonized steel slag separately, then ball-mill them to a maximum particle size of less than 60 μm, weigh them in proportion and set aside; (7) Place bentonite and shield sand in a mixer and stir them at a stirring speed of 800 to 1000 r / min for 10 to 15 minutes to make them uniform; place carbonized steel slag in a mixer and stir them at a stirring speed of 800 to 1000 r / min for 5 to 8 minutes; (8) The stirred material and high temperature sintered high calcium sulphoaluminate cement clinker are subjected to ultrafine ball milling. The particle sizes of high-calcium sulphoaluminate cement clinker sintered at high temperature are 2-8 μm and 10-22 μm, respectively, with a mass ratio of 3:7; the particle size of steel slag is 4-8 μm; (9) The particle sizes of the shield sand-bentonite mixture after ultrafine ball milling are 0-4 μm and 4-8 μm, respectively, with a mass ratio of 1:1; (10) The product after ultrafine ball milling was placed in a blender and mixed thoroughly, 3 / 4 of water was added, and the mixture was stirred at a stirring speed of 1200-1300 r / min for 2-3 min to ensure that the mixture was fully mixed. (11) Add admixtures and 1 / 4 of water, stir at a stirring speed of 1200-1300 r / min for 2 minutes to obtain a high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material.

2. The high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material according to claim 1, characterized in that: The main chemical components of high-temperature sintered high-calcium sulphoaluminate cement clinker are: CaO accounting for 45-50 parts by weight, SiO2 accounting for 3-10 parts by weight, Al2O3 accounting for 25-36 parts by weight, Fe2O3 accounting for 2-4 parts by weight, SO3 accounting for 5-9 parts by weight, and the main mineral components are C4A3S, C2S, and C4AF.

3. The high-temperature sintered high-calcium sulphoaluminate red mud-based grouting material according to claim 1, characterized in that: In step (5), the steel slag specimen is subjected to preliminary carbonization treatment. The steel slag specimen is placed in an environment with a temperature of 20±1°C and a relative humidity of 60% to 80% for curing for 60 minutes, and then placed in a carbonization reactor. 99.9% CO2 gas is introduced for carbonization curing. During the curing period, the CO2 partial pressure of the system is kept constant at 0.35 MPa.

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