Red-mud-based cementing material based on efficient drying, component homogenization and activity improvement, and preparation method therefor

Abstract

The present invention belongs to the field of resource utilization of building materials and solid waste, and relates to a red-mud-based cementing material based on efficient drying, component homogenization and activity improvement, and a preparation method therefor. The preparation method comprises: adding a filter aid to red mud to carry out sedimentation, then subjecting same to filter pressing until the water content is 14-16%, then drying the solid material, which has been subjected to filter pressing, until the water content is 4% or below, and finally grinding same to obtain the product. The filter aid comprises the following raw materials: 10-30 parts of polyaluminum chloride, 5-15 parts of polyaluminum sulfate, 1000-1200 parts of blast furnace slag or fly ash, 700-900 parts of steel slag, 400-600 parts of carbide slag or alkaline residues, and 300-400 parts of desulfurized gypsum or phosphogypsum or fluorgypsum. By means of the present invention, the dehydration efficiency of red mud can be improved, the red-mud-based cementing material can also be prepared in one step; the preparation process for the red-mud-based cementing material is simplified; and the prepared red-mud-based cementing material has the advantages of a high mechanical strength, high durability and erosion resistance.

Description

Red mud-based gelling material and preparation method based on efficient drying, component homogenization and activity enhancement

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present invention claims priority to Chinese patent application No. 202410120633.X filed with the State Intellectual Property Office of China on January 29, 2024, entitled “Red mud-based cementitious material and preparation method based on efficient drying-component homogenization-activity enhancement”, the entire contents of which are incorporated by reference into the present invention and constitute a part of the present invention for all purposes. Technical Field

[0003] The present invention belongs to the field of building materials and solid waste resource utilization, and relates to a red mud-based gelling material based on efficient drying-component homogenization-activity enhancement and a preparation method. Background Art

[0004] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0005] Currently, red mud is mainly used in the preparation of building materials, soil remediation, environmental protection and other fields, and the preparation of cement-based binders is the most effective way to achieve large-scale, high-value-added utilization of red mud. Studies have shown that red mud can be prepared into concrete admixtures, grouting materials, road engineering materials, etc. However, the crux of the current difficulty in promoting and applying red mud on a large scale is its high water content. The water content of red mud in storage yards is about 30%, while the preparation of cement-based binders requires a water content of less than 4%. Therefore, the difficulty of dehydrating red mud and the high cost of dehydration have become technical difficulties that restrict the application of large-scale red mud in engineering projects.

[0006] In terms of red mud dewatering, the technologies that have been reported are mainly drying and filtration, which generally have defects such as high cost and low dewatering efficiency. In recent years, relevant researchers have conducted a lot of research work on new technologies for efficient red mud dewatering. Among them, the patent "A Bayer red mud dehydration and preheating device before sintering into the kiln" discloses a method and process for dehydrating red mud, but the moisture content of the red mud after dehydration is still 20%, which does not meet the performance requirements for preparing cement-like cementitious materials; the patent "A dehydrating agent and its preparation method and application, red mud dehydration method" discloses a preparation method and dehydration process of a new red mud dehydrating agent, but after dehydration using this technology, the red mud moisture content is 6.5-18.5%, which still does not meet the performance requirements for preparing cement-like cementitious materials; the patent "Bayer process red mud dehydration method for dry feeding sintering of alumina by serial method" discloses a technology that mainly uses mechanical dehydration to reduce the moisture content of the separated and washed Bayer process red mud to 35-45%, and then discharges it into the red mud drying yard or existing red mud yard through a pump for natural drying and mechanical turning to further reduce the moisture content of the red mud. When the moisture content of red mud drops below 15%, it is transported back to the alumina plant for batching and calcination. This technology is time-consuming and costly, and the moisture content does not meet the performance requirements for preparing cement-based gelling materials.

[0007] In summary, the current red mud dehydration processes do not meet the moisture content requirements for preparing cement-based binders. Summary of the Invention

[0008] In order to address the deficiencies of the prior art, the purpose of the present invention is to provide a red mud-based cementitious material and a preparation method based on the integration of efficient drying, component homogenization and activity enhancement. The present invention can not only improve the dehydration efficiency of red mud, but also prepare red mud-based cementitious material in one step, simplify the preparation process of red mud-based cementitious material, and the prepared red mud-based cementitious material has the advantages of high mechanical strength, high durability, corrosion resistance, and green environmental protection, and can be used in construction fields such as bridge engineering, road engineering, tunnel engineering, and municipal engineering.

[0009] In order to achieve the above object, the technical solution of the present invention is:

[0010] On the one hand, a preparation method of red mud-based gelling material based on efficient drying-component homogenization-activity enhancement is provided. According to the mass ratio of red mud to filter aid of 1 to 3:1, the filter aid is added to the red mud for sedimentation, and then filtered to a moisture content of 14 to 16%. Then, the waste heat of the alumina plant is passed into the grinding equipment, and the solid material after the filter press is ground and dried. Finally, the moisture content of the red mud-based gelling material is less than 4%, and the specific surface area is 350 to 450 m 2 / kg, that is;

[0011] The filter aid comprises the following raw materials in terms of weight percentage:

[0012] 10-30 parts of polyaluminium chloride, 5-15 parts of polyaluminium sulfate, 1000-1200 parts of blast furnace slag or fly ash, 700-900 parts of steel slag, 400-600 parts of carbide slag or alkali slag, 300-400 parts of desulfurised gypsum or phosphogypsum or fluorinated gypsum.

[0013] On the other hand, a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement is obtained by the above preparation method.

[0014] The third aspect is the application of the above-mentioned red mud-based cementitious material based on efficient drying, component homogenization and activity enhancement in bridge engineering, road engineering, tunnel engineering or municipal engineering.

[0015] The beneficial effects of the present invention are:

[0016] 1) In the preparation method of the present invention, a filter aid is added, and the filter aid contains polyaluminum chloride and polyaluminum sulfate. During the red mud dehydration process, the filter aid not only has a flocculation effect to improve the dehydration efficiency, but also the aluminum element can participate in the geopolymerization process of the red mud-based cementitious material, thereby improving the working performance of the red mud-based cementitious material; secondly, the chloride ions and sulfate ions therein have a salt-stimulating effect on solid wastes such as red mud, blast furnace slag, and steel slag, thereby promoting the hydration process of the red mud-based cementitious material system; furthermore, polyaluminum chloride and polyaluminum sulfate can solidify and dispose of heavy metals such as lead, arsenic, and chromium present in the red mud, thereby ensuring the green and environmentally friendly characteristics of the red mud-based cementitious material.

[0017] 2) The present invention uses blast furnace slag, fly ash, steel slag, carbide slag, alkali residue, desulfurized gypsum and other components in the filter aid to play the role of a skeleton structure in the red mud slurry to a certain extent, and maintains the porous structure of the red mud filter cake by forming a hard grid skeleton, thereby effectively solving the compressibility problem of the red mud and improving the dehydration efficiency of the red mud. In addition, the blast furnace slag, fly ash, steel slag, carbide slag, alkali residue, desulfurized gypsum and other components in the filter aid are also the main components for preparing red mud-based cementitious materials. They work together with red mud to prepare red mud-based cementitious materials with short setting time, high mechanical strength, strong durability, green and environmental protection, and low price through geopolymer reaction. It can completely replace silicate cement and be applied in bridge engineering, road engineering, tunnel engineering, municipal engineering and other construction fields.

[0018] 3) In the original drying process, the water content of red mud is relatively high. As the drying progresses, the red mud agglomerates, hindering the continued evaporation of water. More energy is required to reduce the water content of the red mud to below 4%. The addition of filter aids in the present invention can form a grid skeleton to maintain the porous structure of the red mud filter cake, which is not only beneficial to improving the dehydration efficiency of the filter press process, but also the porous structure formed is more conducive to the volatilization of water in the drying process, thereby improving the dehydration efficiency of the drying process and reducing energy consumption. On the other hand, the filter aid and red mud can undergo a slight geopolymerization reaction under the action of the alkalinity of the red mud to form a hydration product with a three-dimensional skeleton structure, further improving the dehydration efficiency of the red mud. In the drying process, the present invention can use industrial waste heat to further dry and grind the red mud-filter aid composite system after filter press to obtain a red mud-based gelling material. The industrial waste heat of alumina enterprises can be used to dry the red mud-filter aid composite system, and the industrial waste heat can be used to improve the gelling activity of solid wastes such as red mud, reduce energy consumption and production costs, and promote the coordinated development of alumina enterprises and building materials production enterprises, reduce the transportation links of raw materials such as red mud in the production process, save costs, and reduce environmental pollution.

[0019] 4) In the preparation method of the present invention, the utilization rate of red mud is high, and other solid wastes are synergistically utilized, so that solid wastes can be utilized in large quantities and resource utilization of solid wastes such as red mud can be realized.

[0020] 5) In conventional technologies, filter aids remain in the red mud filter cake, causing the red mud to increase in volume and weight, increasing subsequent treatment and disposal costs. This invention selects industrial solid waste that can be used in conjunction with red mud to produce cementitious materials as a filter aid, achieving the dual purpose of red mud dehydration and cementitious material production with a simple process. DETAILED DESCRIPTION

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] Given that one of the bottlenecks in preparing cement-based cementitious materials from red mud is the high moisture content and high dehydration cost of red mud, the present invention proposes a red mud-based cementitious material and preparation method based on efficient drying, component homogenization and activity enhancement.

[0024] A typical embodiment of the present invention provides a method for preparing a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement. The method comprises adding the filter aid to the red mud for sedimentation according to a mass ratio of red mud to filter aid of 1 to 3:1, and then filtering to a moisture content of 14 to 16%. The waste heat of the alumina plant is then passed through the grinding equipment, and the solid material after filtering is ground and dried. The final red mud-based gelling material has a moisture content of less than 4% and a specific surface area of ​​350 to 450 m 2 / kg, that is;

[0025] The filter aid comprises the following raw materials in terms of weight percentage:

[0026] 10-30 parts of polyaluminium chloride, 5-15 parts of polyaluminium sulfate, 1000-1200 parts of blast furnace slag or fly ash, 700-900 parts of steel slag, 400-600 parts of carbide slag or alkali slag, 300-400 parts of desulfurised gypsum or phosphogypsum or fluorinated gypsum.

[0027] In some embodiments, the filter aid comprises the following raw materials, calculated by weight percentage:

[0028] 10-30 parts of polyaluminium chloride, 5-15 parts of polyaluminium sulfate, 1000-1200 parts of blast furnace slag, 700-900 parts of steel slag, 400-600 parts of carbide slag or alkali slag, and 300-400 parts of desulfurised gypsum, phosphogypsum or fluorstyrene. Studies have shown that in the filter aid system of the present invention, blast furnace slag is more conducive to improving the setting rate and mechanical properties of red mud-based cementitious materials than fly ash.

[0029] In some embodiments, the filter aid comprises the following raw materials, calculated by weight percentage:

[0030] 10-30 parts polyaluminium chloride, 5-15 parts polyaluminium sulfate, 1000-1200 parts blast furnace slag, 700-900 parts steel slag, 400-600 parts carbide slag or alkali slag, and 300-400 parts fluorgypsum. Studies have shown that in the filter aid system of the present invention, red mud-based cementitious materials prepared using fluorgypsum have a shorter initial setting time and higher mechanical properties than gypsum.

[0031] In some embodiments, the mass ratio of red mud to filter aid is 1 to 1.5: 1. Studies have shown that under such conditions, the mechanical properties of the obtained red mud-based cementitious material are better.

[0032] In some embodiments, the polyaluminium chloride is in liquid state, has a neutrality level n of 1 to 3, and a basicity greater than 70%.

[0033] Polyaluminum chloride not only has a flocculation effect during the dehydration process of red mud, but the aluminum element in it can also participate in the geopolymerization process of red mud-based cementitious materials, thereby improving the working performance of red mud-based cementitious materials; secondly, chloride ions have a salt-stimulating effect on solid wastes such as red mud, blast furnace slag, and steel slag, thereby promoting the hydration process of cement-based cementitious materials systems; furthermore, polyaluminum chloride can dispose of heavy metals such as lead, arsenic, and chromium present in red mud, thereby ensuring the green and environmentally friendly characteristics of red mud-based cementitious materials.

[0034] In some embodiments, the polyaluminum sulfate is liquid and contains 7-17% aluminum.

[0035] Polyaluminum sulfate not only has a flocculation effect during the dehydration process of red mud, but the aluminum element in it can also participate in the geopolymerization process of red mud-based cementitious materials, thereby improving the working performance of red mud-based cementitious materials; secondly, sulfate ions have a salt-stimulating effect on solid wastes such as red mud, blast furnace slag, and steel slag, thereby promoting the hydration process of cement-based cementitious materials system.

[0036] The red mud described in the present invention is the residue discharged from the Bayer aluminum production process. Its main components are Al2O3, SiO2, Fe2O3, Na2O, etc., and it has a large specific surface area, has a micro-aggregate filling function and potential gelling activity. After activation treatment, it has the potential to prepare mortar / concrete / road structure admixtures.

[0037] The blast furnace slag of the present invention mainly consists of Al2O3, SiO2, and CaO. Its mineral phase is composed of glassy silicon-aluminum components. It has high gelling activity and can supplement the calcium source in red mud-based gelling materials. It can also provide skeleton support for the red mud filter cake and improve the incompressibility of the red mud filter cake. The blast furnace slag needs to be ground to a specific surface area of ​​350-450m 2 / kg.

[0038] The steel slag described in the present invention is solid waste generated during the steelmaking process in the steel industry, including converter slag, open-hearth slag and electric furnace slag. The main components of steel slag are Al2O3, SiO2, and CaO, and its mineral phase composition contains dicalcium silicate and tricalcium silicate. It has high gelling activity, can improve the gelling activity of red mud-based gelling materials, and can provide skeleton support for red mud filter cakes, thereby improving the incompressibility of red mud filter cakes. The steel slag needs to be ground to a specific surface area of ​​350-450m 2 / kg.

[0039] The fly ash described in the present invention is a solid waste generated during the combustion of coal in coal-fired power plants. The main chemical components of fly ash are Al2O3 and SiO2. It has micro-aggregate filling, morphological effect and pozzolanic effect, and can be used in conjunction with red mud to prepare cement-based geopolymer cementitious materials. Fly ash needs to be ground to a specific surface area of ​​350-450m 2 / kg.

[0040] The alkali residue described in the present invention is the waste residue discharged when producing sodium carbonate and sodium bicarbonate in the chemical industry, and is mainly composed of calcium and magnesium components. The present invention mainly utilizes Ca(OH)2 and Mg(OH)2 in the alkali residue to provide active stimulation and volcanic ash effect, and the alkali residue has strong adsorption and has a good adsorption and solidification effect on heavy metals. The alkali residue needs to be ground to a specific surface area of ​​350-450m 2 / kg.

[0041] The main components of the desulfurized gypsum, phosphogypsum or fluorgypsum described in the present invention are CaSO4·2H2O. The main chemical composition of various types of solid waste gypsum is CaSO4·2H2O, which can provide a calcium source in the red mud-based cementitious material system and can also provide salt stimulation of sulfate ions. In addition, it can provide a skeleton support for the red mud filter cake and improve the incompressibility of the red mud filter cake. Desulfurized gypsum, phosphogypsum or fluorgypsum needs to be ground to a specific surface area of ​​350-450m 2 / kg.

[0042] In the present invention, the various filter aids can undergo a slight geopolymerization reaction under the alkalinity of the red mud slurry to generate a Na2O-CaO-SiO2-Al2O3-H2O gel with a three-dimensional network structure. On the basis of the single-component skeleton support, the water flow channels in the red mud filter cake are further increased, thereby further improving the dehydration efficiency of the red mud.

[0043] In some embodiments, first, according to the raw material ratio in the filter aid, polyaluminum chloride, polyaluminum sulfate, fly ash, alkali slag or carbide slag, desulfurization gypsum or phosphogypsum or fluorgypsum are mixed as component 1 and added to the red mud and stirred evenly. After 0.5 to 1 hour, steel slag is added to the red mud slurry as component 2, and then stirred for 0.2 to 0.5 hours. After settling for 0.4 to 0.6 hours, filter pressing is immediately performed.

[0044] Alternatively, first, according to the raw material ratio in the filter aid, polyaluminum chloride, polyaluminum sulfate, alkali slag or carbide slag, desulfurization gypsum or phosphogypsum or fluorgypsum are mixed as component 1 and added to the red mud and stirred evenly. After 0.5 to 1 hour, blast furnace slag and steel slag are mixed as component 2 and added to the red mud slurry, and then stirred for 0.2 to 0.5 hours. After settling for 0.4 to 0.6 hours, filter pressing is immediately performed.

[0045] First, polyaluminium chloride and polyaluminium sulfate have a settling effect on red mud slurry and can be added in advance. Second, filter aids such as fly ash, alkali slag, carbide slag, desulfurised gypsum, phosphogypsum, and fluorgypsum have low gelling activity and can be added to the red mud slurry in advance to allow them to fully contact the alkaline components in the red mud, thereby increasing their gelling activity. Under the action of the alkaline components, they can form a three-dimensional geopolymer gel, improving the filter aid effect. Finally, because other filter aids such as blast furnace slag and steel slag have high gelling activity, they will react rapidly in the alkaline environment of the red mud slurry. Controlling the reaction time within 0.2 to 0.5 hours can not only produce hydration products to improve dehydration efficiency, but also avoid excessive reaction time and prevent the performance of red mud-based cementitious materials from deteriorating. In addition, uniform stirring facilitates better contact between the filter aid and the red mud, thereby reducing settling time.

[0046] In some embodiments, industrial waste heat is used as a heat source for drying. This heat can dry out residual moisture in the red mud-filter aid composite system and thermally treat raw materials such as red mud, steel slag, and fly ash, thereby increasing their gelling activity. Furthermore, this reduces drying costs and improves waste heat utilization efficiency.

[0047] In one or more embodiments, the temperature of the industrial waste heat is 80 to 300 degrees Celsius.

[0048] In some embodiments, the powder is ground to a specific surface area of ​​350 to 450 m 2 / kg.

[0049] Another embodiment of the present invention provides a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement, which is obtained by the above-mentioned preparation method.

[0050] A third embodiment of the present invention provides an application of the above-mentioned red mud-based gelling material based on efficient drying, component homogenization and activity enhancement in bridge engineering, road engineering, tunnel engineering or municipal engineering.

[0051] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0052] Example 1

[0053] A method for preparing a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement comprises the following steps:

[0054] (1) First, 10 parts of polyaluminium chloride, 5 parts of polyaluminium sulfate, 1000 parts of blast furnace slag, 700 parts of steel slag, 400 parts of carbide slag, and 300 parts of desulfurized gypsum are prepared as a filter aid for red mud dewatering. The carbide slag and desulfurized gypsum are directly mixed, and then mixed with polyaluminium chloride and polyaluminium sulfate to prepare a filter aid as component 1. The blast furnace slag and steel slag are directly mixed as component 2.

[0055] (2) According to the ratio of red mud to filter aid of 3:1, component 1 was first put into the red mud sedimentation tank and stirred for 0.5 hours. Then component 2 was added thereto, stirred for 0.2 hours, and allowed to stand for 0.5 hours.

[0056] (3) The red mud-filter aid composite system is filtered by mechanical filtration until the water content is about 15%.

[0057] (4) After filtration, the red mud-filter aid composite system is transported to the industrial waste heat-grinding synergistic utilization system through a conveyor belt. The red mud-filter aid composite system is dried to a moisture content of 4% by industrial waste heat, and the red mud-filter aid composite system is ground to a specific surface area of ​​400m 2 / kg, and red mud-based gelling material is obtained.

[0058] Example 2

[0059] A method for preparing a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement comprises the following steps:

[0060] (1) A filter aid for red mud dewatering was prepared by mixing 10 parts of polyaluminium chloride, 5 parts of polyaluminium sulfate, 1000 parts of blast furnace slag, 700 parts of steel slag, 400 parts of carbide slag, and 300 parts of desulfurised gypsum. The carbide slag and desulfurised gypsum were directly mixed and then mixed with polyaluminium chloride and polyaluminium sulfate to prepare the filter aid as component 1. The blast furnace slag and steel slag were directly mixed as component 2.

[0061] (2) According to the ratio of red mud to filter aid of 1:1, component 1 was first put into the red mud sedimentation tank and stirred for 0.5 hours. Then component 2 was added thereto, stirred for 0.2 hours, and allowed to stand for 0.5 hours.

[0062] (3) The red mud-filter aid composite system is filtered by mechanical filtration until the water content is about 15%.

[0063] (4) After filtration, the red mud-filter aid composite system is transported to the industrial waste heat-grinding synergistic utilization system through a conveyor belt, and the red mud-filter aid composite system is dried to a moisture content of less than 4% by industrial waste heat, and the red mud-filter aid composite system is ground to a specific surface area of ​​400m 2 / kg, and red mud-based gelling material is obtained.

[0064] Example 3

[0065] A method for preparing a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement comprises the following steps:

[0066] (1) A filter aid for red mud dewatering was prepared by mixing 10 parts of polyaluminium chloride, 5 parts of polyaluminium sulfate, 1000 parts of fly ash, 900 parts of steel slag, 600 parts of alkali residue, and 400 parts of phosphogypsum. The fly ash, alkali residue, and phosphogypsum were directly mixed and then mixed with polyaluminium chloride and polyaluminium sulfate to prepare the filter aid as component 1. The steel slag was directly used as component 2.

[0067] (2) According to the ratio of red mud to filter aid of 3:1, component 1 was first put into the red mud sedimentation tank and stirred for 0.5 hours. Then component 2 was added thereto, stirred for 0.2 hours, and allowed to stand for 0.5 hours.

[0068] (3) The red mud-filter aid composite system is filtered by mechanical filtration until the water content is about 15%.

[0069] (4) After filtration, the red mud-filter aid composite system is transported to the industrial waste heat-grinding synergistic utilization system through a conveyor belt, and the red mud-filter aid composite system is dried to a moisture content of less than 4% by industrial waste heat, and the red mud-filter aid composite system is ground to a specific surface area of ​​400m 2 / kg, and red mud-based gelling material is obtained.

[0070] Example 4

[0071] A method for preparing a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement comprises the following steps:

[0072] (1) A filter aid for red mud dewatering was prepared by mixing 30 parts of polyaluminium chloride, 15 parts of polyaluminium sulfate, 1200 parts of blast furnace slag, 700 parts of steel slag, 600 parts of alkali residue, and 300 parts of fluorgypsum. The alkali residue and fluorgypsum were directly mixed and then mixed with polyaluminium chloride and polyaluminium sulfate to prepare the filter aid as component 1. The blast furnace slag and steel slag were directly mixed as component 2.

[0073] (2) According to the ratio of red mud to filter aid of 1:1, component 1 was first put into the red mud sedimentation tank and stirred for 0.5 hours. Then component 2 was added thereto, stirred for 0.2 hours, and allowed to stand for 0.5 hours.

[0074] (3) The red mud-filter aid composite system is filtered by mechanical filtration until the water content is about 15%.

[0075] (4) After filtration, the red mud-filter aid composite system is transported to the industrial waste heat-grinding synergistic utilization system through a conveyor belt, and the red mud-filter aid composite system is dried to a moisture content of less than 4% by industrial waste heat, and the red mud-filter aid composite system is ground to a specific surface area of ​​400m 2 / kg, and red mud-based gelling material is obtained.

[0076] Example 5

[0077] A method for preparing a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement comprises the following steps:

[0078] (1) A filter aid for red mud dewatering was prepared by mixing 10 parts of polyaluminium chloride, 15 parts of polyaluminium sulfate, 1200 parts of fly ash, 700 parts of steel slag, 600 parts of carbide slag, and 400 parts of phosphogypsum. The fly ash, carbide slag, and phosphogypsum were directly mixed and then mixed with polyaluminium chloride and polyaluminium sulfate to prepare the filter aid as component 1. The steel slag was directly used as component 2.

[0079] (2) According to the ratio of red mud to filter aid of 1:1, component 1 was first put into the red mud sedimentation tank and stirred for 0.5 hours. Then component 2 was added thereto, stirred for 0.2 hours, and allowed to stand for 0.5 hours.

[0080] (3) The red mud-filter aid composite system is filtered by mechanical filtration until the water content is about 15%.

[0081] (4) After filtration, the red mud-filter aid composite system is transported to the industrial waste heat utilization system through a conveyor belt, and the red mud-filter aid composite system is dried to a moisture content of less than 4% by industrial waste heat, and the red mud-filter aid composite system is ground to a specific surface area of ​​400m 2 / kg, and red mud-based gelling material is obtained.

[0082] Example 6

[0083] A method for preparing a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement comprises the following steps:

[0084] (1) A filter aid for red mud dewatering was prepared by mixing 30 parts of polyaluminium chloride, 5 parts of polyaluminium sulfate, 1200 parts of blast furnace slag, 700 parts of steel slag, 400 parts of alkali residue, and 400 parts of phosphogypsum. The alkali residue and phosphogypsum were directly mixed and then mixed with polyaluminium chloride and polyaluminium sulfate to prepare the filter aid as component 1. The blast furnace slag and steel slag were directly mixed as component 2.

[0085] (2) According to the ratio of red mud to filter aid of 1:1, component 1 was first put into the red mud sedimentation tank and stirred for 0.5 hours. Then component 2 was added thereto, stirred for 0.2 hours, and allowed to stand for 0.5 hours.

[0086] (3) The red mud-filter aid composite system is filtered by mechanical filtration until the water content is about 15%.

[0087] (4) After filtration, the red mud-filter aid composite system is transported to the industrial waste heat-grinding synergistic utilization system through a conveyor belt, and the red mud-filter aid composite system is dried to a moisture content of less than 4% by industrial waste heat, and the red mud-filter aid composite system is ground to a specific surface area of ​​400m 2 / kg, and red mud-based gelling material is obtained.

[0088] Example 7

[0089] A method for preparing a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement comprises the following steps:

[0090] (1) First, 10 parts of polyaluminium chloride, 5 parts of polyaluminium sulfate, 1000 parts of blast furnace slag, 700 parts of steel slag, 400 parts of carbide slag and 300 parts of desulfurized gypsum were prepared as a filter aid for red mud dewatering, wherein the carbide slag and desulfurized gypsum were directly mixed and then mixed with polyaluminium chloride and polyaluminium sulfate to prepare a filter aid as component 1. The blast furnace slag and steel slag were directly mixed as component 2.

[0091] (2) According to the ratio of red mud to filter aid of 3:1, component 1 was first put into the red mud sedimentation tank and stirred for 0.5 hours. Then component 2 was added thereto, stirred for 0.5 hours, and allowed to stand for 0.5 hours.

[0092] (3) The red mud-filter aid composite system is filtered by mechanical filtration until the water content is about 15%.

[0093] (4) After filtration, the red mud-filter aid composite system is transported to the industrial waste heat-grinding synergistic utilization system through a conveyor belt. The red mud-filter aid composite system is dried to a moisture content of 4% by industrial waste heat, and the red mud-filter aid composite system is ground to a specific surface area of ​​400m 2 / kg, and red mud-based gelling material is obtained.

[0094] Comparative Example 1

[0095] A method for preparing a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement comprises the following steps:

[0096] (1) A filter aid for red mud dewatering was prepared by mixing 10 parts of polyaluminium chloride, 1000 parts of blast furnace slag, 700 parts of steel slag, 400 parts of carbide slag and 300 parts of desulfurised gypsum. The carbide slag and desulfurised gypsum were directly mixed and then mixed with polyaluminium chloride to prepare a filter aid as component 1. The blast furnace slag and steel slag were directly mixed as component 2.

[0097] (2) According to the ratio of red mud to filter aid of 3:1, component 1 was first put into the red mud sedimentation tank and stirred for 0.5 hours. Then component 2 was added thereto, stirred for 0.2 hours, and allowed to stand for 0.5 hours.

[0098] (3) The red mud-filter aid composite system is filtered by mechanical filtration until the water content is about 15%.

[0099] (4) After filtration, the red mud-filter aid composite system is transported to the industrial waste heat-grinding synergistic utilization system through a conveyor belt. The red mud-filter aid composite system is dried to a moisture content of 4% by industrial waste heat, and the red mud-filter aid composite system is ground to a specific surface area of ​​400m 2 / kg, and red mud-based gelling material is obtained.

[0100] Comparative Example 2

[0101] A method for preparing a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement comprises the following steps:

[0102] (1) A filter aid for red mud dewatering was prepared by mixing 5 parts of polyaluminium sulfate, 1000 parts of blast furnace slag, 700 parts of steel slag, 400 parts of carbide slag and 300 parts of desulfurised gypsum. The carbide slag and desulfurised gypsum were directly mixed and then mixed with polyaluminium sulfate to prepare a filter aid as component 1. The blast furnace slag and steel slag were directly mixed as component 2.

[0103] (2) According to the ratio of red mud to filter aid of 3:1, component 1 was first put into the red mud sedimentation tank and stirred for 0.5 hours. Then component 2 was added thereto, stirred for 0.2 hours, and allowed to stand for 0.5 hours.

[0104] (3) The red mud-filter aid composite system is filtered by mechanical filtration until the water content is about 15%.

[0105] (4) After filtration, the red mud-filter aid composite system is transported to the industrial waste heat-grinding synergistic utilization system through a conveyor belt. The red mud-filter aid composite system is dried to a moisture content of 4% by industrial waste heat, and the red mud-filter aid composite system is ground to a specific surface area of ​​400m 2 / kg, and red mud-based gelling material is obtained.

[0106] Comparative Example 3

[0107] A method for preparing a red mud-based gelling material based on efficient drying, component homogenization and activity enhancement comprises the following steps:

[0108] (1) First, 10 parts of polyaluminium chloride, 5 parts of polyaluminium sulfate, 1000 parts of blast furnace slag, 700 parts of steel slag, 400 parts of carbide slag and 300 parts of desulfurised gypsum are prepared as a filter aid for red mud dewatering, wherein the carbide slag, desulfurised gypsum, blast furnace slag and steel slag are directly mixed and then mixed with polyaluminium chloride and polyaluminium sulfate to prepare a filter aid.

[0109] (2) Pour the red mud into the red mud sedimentation tank at a ratio of 3:1, stir for 1 hour, and let it stand for 0.2 hour.

[0110] (3) The red mud-filter aid composite system is filtered by mechanical filtration until the water content is about 15%.

[0111] (4) After filtration, the red mud-filter aid composite system is transported to the industrial waste heat-grinding synergistic utilization system through a conveyor belt. The red mud-filter aid composite system is dried to a moisture content of 4% by industrial waste heat, and the red mud-filter aid composite system is ground to a specific surface area of ​​400m 2 / kg, and red mud-based gelling material is obtained.

[0112] Performance Testing

[0113] The performance of red mud-based cementitious materials was tested with reference to GB 175-2023 “General Portland Cement”, and the results are shown in Table 1.

[0114] Table 1 Properties of red mud-based gelling materials prepared in various embodiments

[0115] Analysis of the test data shows that the smaller the mass ratio of red mud to filter aid, the better the performance of the prepared red mud-based cementitious material; blast furnace slag has better effect than fly ash in the system, and desulfurization gypsum has better effect than phosphogypsum and fluorgypsum in the system; alkali slag has better effect than calcium carbide slag in the system; polyaluminum chloride and polyaluminum sulfate have little effect on the performance of red mud-based cementitious materials, but have a certain degree of improvement effect.

[0116] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing red mud-based gelling materials based on efficient drying, component homogenization and activity enhancement, characterized in that: According to the mass ratio of red mud to filter aid of 1 to 3:1, the filter aid is added to the red mud for sedimentation, and then filtered to a moisture content of 14 to 16%. The solid material after filtration is then dried to a moisture content of less than 4%, and finally ground to obtain the product; The filter aid comprises the following raw materials in terms of weight percentage: 10-30 parts of polyaluminium chloride, 5-15 parts of polyaluminium sulfate, 1000-1200 parts of blast furnace slag or fly ash, 700-900 parts of steel slag, 400-600 parts of carbide slag or alkali slag, 300-400 parts of desulfurised gypsum or phosphogypsum or fluorinated gypsum.

2. The method for preparing red mud-based gelling materials based on efficient drying, component homogenization and activity enhancement according to claim 1, characterized in that: The filter aid comprises the following raw materials in terms of weight percentage: 10-30 parts of polyaluminium chloride, 5-15 parts of polyaluminium sulfate, 1000-1200 parts of blast furnace slag, 700-900 parts of steel slag, 400-600 parts of carbide slag or alkali slag, 300-400 parts of desulfurised gypsum, phosphogypsum or fluorinated gypsum; Alternatively, the filter aid comprises the following raw materials in percentage by weight: 10-30 parts of polyaluminium chloride, 5-15 parts of polyaluminium sulfate, 1000-1200 parts of blast furnace slag, 700-900 parts of steel slag, 400-600 parts of carbide slag or alkali slag, and 300-400 parts of fluorgypsum.

3. The method for preparing red mud-based gelling materials based on efficient drying, component homogenization and activity enhancement according to claim 1, characterized in that: The mass ratio of red mud to filter aid is 1 to 3:

1.

4. The method for preparing red mud-based gelling materials based on efficient drying, component homogenization and activity enhancement according to claim 1, characterized in that: The polyaluminium chloride is in liquid state, with a neutrality degree n of 1 to 3 and a basicity greater than 70%.

5. The method for preparing red mud-based gelling materials based on efficient drying, component homogenization and activity enhancement according to claim 1, characterized in that: The polyaluminium sulfate is liquid and contains 7-17% aluminium.

6. The method for preparing red mud-based gelling materials based on efficient drying, component homogenization and activity enhancement according to claim 1, characterized in that: First, according to the raw material ratio of the filter aid, polyaluminium chloride, polyaluminium sulfate, fly ash, alkali residue or carbide slag, desulfurised gypsum or phosphogypsum or fluorstyrene is mixed as component 1 and added to the red mud and stirred evenly. After 0.5 to 1 hour, steel slag is added to the red mud slurry as component 2, and stirred for another 0.2 to 0.5 hours. After settling for 0.4 to 0.6 hours, filter pressing is immediately performed; Alternatively, first, according to the raw material ratio in the filter aid, polyaluminum chloride, polyaluminum sulfate, alkali slag or carbide slag, desulfurization gypsum or phosphogypsum or fluorgypsum are mixed as component 1 and added to the red mud and stirred evenly. After 0.5 to 1 hour, blast furnace slag and steel slag are mixed as component 2 and added to the red mud slurry, and then stirred for 0.2 to 0.5 hours. After settling for 0.4 to 0.6 hours, filter pressing is immediately performed.

7. The method for preparing red mud-based gelling materials based on efficient drying, component homogenization and activity enhancement according to claim 1, characterized in that: Use industrial waste heat as the heat source for drying; Alternatively, the temperature of industrial waste heat is 80 to 300 degrees Celsius.

8. The method for preparing red mud-based gelling materials based on efficient drying, component homogenization and activity enhancement according to claim 1, characterized in that: Grind to a specific surface area of 350-450m 2 / kg.

9. A red mud-based gelling material based on efficient drying, component homogenization and activity enhancement, characterized by: The method is obtained by any one of claims 1 to 8.

10. Use of the red mud-based gelling material based on efficient drying, component homogenization and activity enhancement according to claim 9 in bridge engineering, road engineering, tunnel engineering or municipal engineering.

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