Manganese slag red mud composite stabilized soil and preparation method and application thereof

Abstract

The present application relates to solid waste resource technology field, disclose a kind of manganese slag red mud composite stabilized soil and its preparation method and application.A kind of manganese slag red mud composite stabilized soil, including by the following mass fraction of solid component is prepared: electrolytic manganese slag 55~70 parts, red mud 20~40 parts, quicklime 5~10 parts, phosphogypsum 8~15 parts, silicon-aluminum adjusting agent 10~15 parts, stabilizing aid 5~10 parts, heavy metal ion stabilizer 1~5 parts, dispersing agent 1~3 parts.The manganese slag red mud composite stabilized soil provided by the present application realizes the large amount of use of electrolytic manganese slag and red mud by the synergistic reaction of red mud and manganese slag, which is beneficial to environmental protection, reduces the demand for natural soil and stone resources, and reduces the cost of building materials.The manganese slag red mud composite stabilized soil has high compressive strength, strong resistance to deformation, good water erosion resistance and good overall stability, and can be well applied to road or infrastructure construction.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and in particular to a manganese slag red mud composite stabilized soil, its preparation method, and its application. Background Technology

[0002] Electrolytic manganese slag is produced during the electrolytic production of metallic manganese. Its main chemical components include SiO2, Al2O3, Fe2O3, and CaSO4. Each ton of electrolytic manganese produces 6 to 8 tons of waste slag. Currently, the main method for treating and disposing of electrolytic manganese slag is wet stockpiling. However, manganese slag contains heavy metals and a large amount of water-soluble salts, and is acidic or weakly acidic. During stockpiling, heavy metal elements such as iron, manganese, and copper can seep into the soil and groundwater, which can have adverse effects on the ecosystem and water resources.

[0003] Red mud is an industrial solid waste generated after extracting alumina from bauxite. Its main chemical components include SiO2, Al2O3, CaO, and Fe2O3, and it appears as a reddish-brown, muddy substance. Red mud contains minerals such as aragonite and calcite, and its discharge and dumping can lead to soil pollution, ecosystem damage, or negative impacts on air quality. The chemical alkalis bound to red mud are difficult to remove and present in large quantities, making the harmless disposal and large-scale utilization of red mud a long-standing challenge.

[0004] Treating electrolytic manganese slag and red mud to meet environmental regulations and sustainable development requirements is a complex and challenging task. Traditional treatment methods typically include storage and landfilling, but these methods do not fully utilize the resource value of these wastes and can easily lead to long-term environmental risks. Another treatment method is to subject the waste to high-temperature thermal treatment or chemical treatment to reduce its toxicity or alter its physical properties, but these methods are generally costly and difficult to implement. Due to the complex chemical composition of manganese slag and red mud, traditional treatment methods struggle to achieve stable treatment results.

[0005] Current road and infrastructure construction places a significant demand on natural soil and rock materials such as clay, loam, soil, gravel, and rock. Large-scale extraction of these natural soil and rock resources can negatively impact land resources and even trigger environmental problems such as ecosystem damage, soil erosion, and air quality deterioration. Therefore, there is an urgent need to develop an alternative material to natural soil and rock to meet the requirements of large-scale road and infrastructure construction. Summary of the Invention

[0006] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, one objective of the present invention is to provide a manganese slag and red mud composite stabilized soil; a second objective is to provide a method for preparing this manganese slag and red mud composite stabilized soil; and a third objective is to provide applications of this manganese slag and red mud composite stabilized soil.

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

[0008] The first aspect of the present invention provides a manganese slag and red mud composite stabilized soil, comprising solid components prepared in the following parts by weight: 55-70 parts of electrolytic manganese slag, 20-40 parts of red mud, 5-10 parts of quicklime, 8-15 parts of phosphogypsum, 10-15 parts of silicon-aluminum modifier, 5-10 parts of stabilizing agent, 1-5 parts of heavy metal ion stabilizer, and 1-3 parts of dispersant.

[0009] The basic principles of this invention are explained as follows:

[0010] 1) When electrolytic manganese slag is used in conjunction with red mud, the calcium sulfate, manganese sulfate, ferric sulfate and other sulfates rich in electrolytic manganese slag can form Ca(OH)2, Mn(OH)2 and other precipitates under appropriate reaction conditions by taking advantage of the strong alkalinity of red mud, thereby accelerating the removal of ammonia through exothermic reaction; at the same time, the acid radicals in manganese slag can neutralize the strong alkalinity of red mud, solving the problems of poor stability and long setting time of manganese slag as an admixture due to its acidic characteristics, as well as the problems of efflorescence and cracking caused by excessive alkali concentration of red mud when it is used in building materials.

[0011] 2) Using electrolytic manganese slag as a sulfate activator and red mud as an alkali activator, composite stabilized soil is prepared by activating manganese slag and red mud, which can improve the stability and compressive strength of the material.

[0012] 3) Electrolytic manganese slag and red mud usually contain trace elements such as hexavalent chromium, mercury, and vanadium (content less than 0.1%). There is a risk of trace element spillage and environmental pollution during the resource utilization process. Heavy metal ion stabilizers can solidify these elements in the mixture of red mud and electrolytic manganese slag, reduce their solubility and migration, and further reduce the impact on the environment.

[0013] 4) The silicon-aluminum modifier can optimize the calcium-silicon ratio and silicon-aluminum ratio of the material system, adjusting the calcium-silicon ratio of the system to 0.6-1.5 and the silicon-aluminum ratio to ≥2. The silicon-aluminum modifier can synergistically promote the cementing activity and improve the sealing rate of heavy metal elements in the mineral composition of the remaining components of the manganese slag red mud composite stabilized soil.

[0014] 5) The stabilizing agent contains a layered structure that can physically adsorb the water attached to the red mud and chemically adsorb the attached alkaline solution. The stabilizing agent can complement the particle size distribution of manganese slag and red mud, achieving overlap of particle size distribution between manganese slag and red mud, improving compaction performance, and will not affect the chemical properties of manganese slag and red mud.

[0015] Preferably, the electrolytic manganese slag comprises the following chemical components by mass percentage: 8.5–9.2% CaO, 33–35% SiO2, 5–6.5% Al2O3, 18–22% Fe2O3, 7.5–8% MnO, and 19–23% SO3.

[0016] Preferably, the water content of the electrolytic manganese slag is 22-28%; more preferably, the water content of the electrolytic manganese slag is 24-26%.

[0017] Preferably, the particle size of the electrolytic manganese slag is 2.5–6.5 μm; more preferably, the particle size of the electrolytic manganese slag is 3.0–6.0 μm.

[0018] Preferably, the particle size of the electrolytic manganese slag is concentrated in the range of 2.0 to 3.0 μm, accounting for 65 to 75%; more preferably, the particle size of the electrolytic manganese slag is concentrated in the range of 2.0 to 3.0 μm, accounting for 68 to 72%.

[0019] Preferably, the pH value of the electrolytic manganese slag leachate is 5.3 to 6.6; more preferably, the pH value of the electrolytic manganese slag leachate is 5.5 to 6.0.

[0020] Preferably, the red mud comprises the following chemical components by mass percentage: 10.31–12.15% SiO2, 19.54–21.67% Al2O3, 36.21–41.58% Fe2O3, 14.57–16.80% NaOH, 1.58–3.05% CaO, 7.33–8.50% Na2O, 5.25–6.20% TiO2, and 0.16–0.35% MgO.

[0021] Preferably, the red mud comprises the following mineral components: aragonite, calcite, opal, gibbsite, and goethite.

[0022] Preferably, the red mud contains 55-70% shale and calcite; more preferably, the red mud contains 60-65% shale and calcite.

[0023] Preferably, the specific gravity of the red mud is 2.7 to 2.9; more preferably, the specific gravity of the red mud is 2.75 to 2.85.

[0024] Preferably, the dry density of the red mud is 1.0–1.3 g / cm³. 3 More preferably, the dry density of the red mud is 1.2–1.3 g / cm³. 3 .

[0025] Preferably, the red mud has a moisture content of 25-35%; more preferably, the red mud has a moisture content of 28-32%.

[0026] Preferably, the liquid limit of the red mud is 40-49%; more preferably, the liquid limit of the red mud is 43-46%.

[0027] Preferably, the plastic limit of the red mud is 30-35%; more preferably, the plastic limit of the red mud is 31-34%.

[0028] Preferably, the pH value of the red mud is 10.5 to 12.0; more preferably, the pH value of the red mud is 11.0 to 11.5.

[0029] Preferably, the quicklime is industrial quicklime with a mesh size of 300-500 mesh and an effective calcium content of 85-90%.

[0030] Preferably, the phosphogypsum is heat-treated at 140–300°C before use to form β-type hemihydrate gypsum; more preferably, the phosphogypsum is heat-treated at 190–250°C before use to form β-type hemihydrate gypsum.

[0031] Preferably, the silica-alumina modifier includes at least one of steel slag waste incinerator slag, non-ferrous metallurgical slag, metakaolin, diorite powder, sodium silicate, and diorite powder.

[0032] Preferably, the apparent density of the silicon-aluminum modifier is 2.6–2.9 g / cm³. 3 More preferably, the apparent density of the silicon-aluminum modifier is 2.7–2.8 g / cm³. 3 .

[0033] Preferably, the specific surface area of ​​the silicon-aluminum modifier is 350–400 m². 2 / kg; More preferably, the specific surface area of ​​the silicon-aluminum modifier is 380-400 m² / kg. 2 / kg.

[0034] Preferably, the stabilizing agent includes at least one of zeolite powder, diatomaceous earth, vermiculite powder, talc powder, clay, shale powder, and fly ash.

[0035] Preferably, the heavy metal ion stabilizer includes at least one of metal hydroxide stabilizers, organic chelating agents, phosphate stabilizers, and lignin-based triaminotriethylamine salt stabilizers.

[0036] Preferably, the heavy metal ion stabilizer includes at least one of aluminum hydroxide, iron hydroxide, polyaluminum sulfate, layered double hydroxide, calcined layered double hydroxide, DTC-type organic chelating agent, disodium hydrogen phosphate, superphosphate, and lignin-based triaminotriethylamine salt.

[0037] Preferably, the dispersant includes at least one of phosphate dispersants, organophosphorus dispersants, sulfate dispersants, alcohol dispersants, cellulose derivative dispersants, polymeric dispersants, and salt dispersants.

[0038] Preferably, the dispersant comprises at least one of sodium tripolyphosphate, sodium hexametaphosphate and sodium pyrophosphate, triethylhexylphosphate, sodium dodecyl sulfate, methylpentanol, cellulose derivatives, polyacrylamide, carboxylates, polycarboxylates, and sulfonates.

[0039] Preferably, the manganese slag red mud composite stabilized soil also includes water.

[0040] Preferably, the mass ratio of water to the total mass of solid components in the manganese slag red mud composite stabilized soil is 1:(4-11).

[0041] The second aspect of the present invention provides a method for preparing the manganese slag red mud composite stabilized soil described in the first aspect of the present invention, comprising the following steps:

[0042] 1) Mix electrolytic manganese slag with red mud, dispersant, and heavy metal ion stabilizer, and let stand to obtain a mixture;

[0043] 2) Add quicklime, phosphogypsum, silica-alumina modifier, stabilizer and water to the mixture, and mix to form manganese slag red mud composite stabilized soil.

[0044] Preferably, in step 1), the electrolytic manganese slag is further subjected to water washing and ammonium salt precipitation pretreatment before use; the specific operation of ammonium salt precipitation of electrolytic manganese slag is as follows: manganese slag is dissolved in an acidic solution, ammonia is added to generate precipitable manganese ammonium salt, supersaturated salts are added to the solution to precipitate the manganese ammonium salt, and the precipitate is separated.

[0045] Preferably, in step 1), the recovery rate of manganese and ammonia nitrogen in the water washing and ammonium salt precipitation pretreatment of the electrolytic manganese slag is ≥80%.

[0046] Preferably, in step 1), the moisture content of the electrolytic manganese slag is controlled to be 20-28% before use.

[0047] Preferably, in step 1), the red mud is further subjected to a pressure filter pretreatment before use.

[0048] Preferably, in step 1), the moisture content of the red mud is controlled to be 25-35% before use.

[0049] Preferably, in step 1), the mechanical equipment used for mixing is a forced mixer with a speed of 10-20 rpm and a mixing time of 5-7 minutes.

[0050] Preferably, in step 1), the standing process is carried out by covering or isolating the air to prevent moisture loss.

[0051] Preferably, in step 1), the settling time is 6 to 10 hours; more preferably, in step 1), the settling time is 7 to 9 hours.

[0052] Preferably, in step 2), the mechanical equipment used for mixing is a forced mixer with a mixer speed of 10-20 rpm and a mixing time of 5-7 minutes.

[0053] The third aspect of the present invention provides the application of the manganese slag red mud composite stabilized soil described in the first aspect of the present invention in road or infrastructure construction.

[0054] Preferably, the manganese slag red mud composite stabilized soil is applied to road construction using the road mixing method, which includes the following steps:

[0055] 1) Mix electrolytic manganese slag with red mud, dispersant, and heavy metal ion stabilizer, and let stand to obtain a mixture;

[0056] 2) Spread the mixture on the road surface, add quicklime, phosphogypsum, silica-alumina modifier, stabilizer and water to the surface, and mix.

[0057] 3) Compacting;

[0058] 4) Maintenance.

[0059] Preferably, in step 1), the electrolytic manganese slag is further subjected to water washing and ammonium salt precipitation pretreatment before use; the specific operation of ammonium salt precipitation of electrolytic manganese slag is as follows: manganese slag is dissolved in an acidic solution, ammonia is added to generate precipitable manganese ammonium salt, supersaturated salts are added to the solution to precipitate the manganese ammonium salt, and the precipitate is separated.

[0060] Preferably, in step 1), the recovery rate of manganese and ammonia nitrogen in the water washing and ammonium salt precipitation pretreatment of the electrolytic manganese slag is 80-85%.

[0061] Preferably, in step 1), the moisture content of the electrolytic manganese slag is controlled to be 20-28% before use.

[0062] Preferably, in step 1), the red mud is further subjected to a pressure filter pretreatment before use.

[0063] Preferably, in step 1), the moisture content of the red mud is controlled to be 25-35% before use.

[0064] Preferably, in step 1), the mechanical equipment used for mixing is a forced mixer.

[0065] Preferably, in step 1), the settling time is 6 to 10 hours; more preferably, in step 1), the settling time is 7 to 9 hours.

[0066] Preferably, in step 2), the mechanical equipment used for mixing is a road mixer with a working speed of 2 to 3.3 km / h, a mixing width of 2300 to 2500 mm, and a mixing depth of 0 to 400 mm.

[0067] Preferably, in step 3), the compaction equipment is a road roller with a travel speed of 2 to 4 km / h.

[0068] Preferably, in step 3), the compaction method is vibratory compaction, the compaction procedure is steady pressure - light vibration rolling - heavy vibration rolling, the number of compaction times is 3 to 5, the vibration frequency is 5 to 30 Hz, and the vibration force is 600 to 800 kg.

[0069] Preferably, in step 4), the curing temperature is 20–25°C and the humidity is 90–95%.

[0070] The beneficial effects of this invention are:

[0071] 1) The manganese slag and red mud composite stabilized soil provided by the present invention utilizes the synergistic reaction of red mud and manganese slag to achieve the large-scale use of electrolytic manganese slag and red mud, which is beneficial to environmental protection, can reduce the demand for natural soil and rock resources, and reduce the cost of building materials; the manganese slag and red mud composite stabilized soil has high compressive strength, strong resistance to deformation, good water erosion resistance, and high overall stability, and can be well applied to highway engineering construction.

[0072] 2) This invention prepares composite stabilized soil by activating manganese slag and red mud, and then enhances the activation effect and achieves high solidification of heavy metal elements through the synergistic effect of external additives such as silicon-aluminum modifier, stabilizing agent, and heavy metal ion stabilizer. The resulting material has good comprehensive performance. The preparation method is simple and practical. Detailed Implementation

[0073] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art.

[0074] The parameters related to the raw materials used in the following examples and comparative examples include:

[0075] 1) Electrolytic manganese slag: It contains the following chemical components by mass percentage: 8.5-9.2% CaO, 33-35% SiO2, 5-6.5% Al2O3, 18-22% Fe2O3, 7.5-8% MnO, and 19-23% SO3; the moisture content is 22-28%; the particle size is 2.5-6.5μm; the particle size is concentrated in the range of 2.0-3.0μm, accounting for 70%; and the pH of the leachate is 5.3-6.6.

[0076] 2) Red mud: Comprising the following chemical components by mass percentage: 10.31–12.15% SiO2, 19.54–21.67% Al2O3, 36.21–41.58% Fe2O3, 14.57–16.80% NaOH, 1.58–3.05% CaO, 7.33–8.50% Na2O, 5.25–6.20% TiO2, and 0.16–0.35% MgO; Mineral components include: aragonite, calcite, opal, gibbsite, and goethite; Aragonite and calcite comprise 60–65% of the mineral composition; specific gravity is 2.8; dry density is 1.3 g / cm³. 3 Moisture content: 25-35%; Liquid limit: 40-49%; Plastic limit: 30-35%; pH value: 10.5-12.0.

[0077] 3) Quicklime: Industrial quicklime, 300 mesh, with an effective calcium content of 85%.

[0078] 4) Phosphogypsum: Before use, it is heated at 140-300℃ to form β-type hemihydrate gypsum.

[0079] 5) Silicon-aluminum modifier: apparent density is 2.6–2.9 g / cm³ 3 ; Specific surface area is 350-400 m² 2 / kg.

[0080] Example 1

[0081] A manganese slag red mud composite stabilized soil, comprising components in parts by weight:

[0082] Electrolytic manganese slag 60 copies Red mud 25 copies quicklime 8 copies phosphogypsum 12 copies Silicon-aluminum modifier 10 copies Stabilizers 5 copies Heavy metal ion stabilizers 3 copies dispersant 3 copies water 15 copies

[0083] The silica-alumina modifier consists of: 10 parts steel slag incinerator slag, 5 parts metakaolin, 3 parts diorite powder, and 1 part sodium silicate; the stabilizer consists of: 10 parts zeolite powder, 5 parts diatomite, and 3 parts talc powder; the heavy metal ion stabilizer is aluminum hydroxide; and the dispersant is sodium tripolyphosphate.

[0084] The preparation method of the above-mentioned manganese slag red mud composite stabilized soil is as follows:

[0085] 1) The electrolytic manganese slag is pretreated by water washing and ammonium salt precipitation. The specific operation is as follows: the manganese slag is dissolved in an acidic solution, ammonia is added to generate precipitable manganese ammonium salt, supersaturated salts are added to the solution to precipitate the manganese ammonium salt, the precipitate is separated, and the moisture content of the residue is controlled at 20-28%; the red mud is pretreated by pressure filtration and the moisture content is controlled at 25-35%.

[0086] 2) The pretreated electrolytic manganese slag is mixed with red mud, dispersant, and heavy metal ion stabilizer using a forced mixer. The mixing speed is 10-20 rpm and the mixing time is 5-7 minutes. The mixture is then allowed to stand for 8 hours to obtain the mixture.

[0087] 3) Add quicklime, phosphogypsum, silica-alumina modifier, stabilizer and water to the mixture, and mix using a forced mixer at a speed of 10-20 rpm for 5-7 minutes to obtain manganese slag red mud composite stabilized soil.

[0088] Example 2

[0089] A manganese slag red mud composite stabilized soil, comprising components in parts by weight:

[0090] Electrolytic manganese slag 55 copies Red mud 20 copies quicklime 5 copies phosphogypsum 8 copies Silicon-aluminum modifier 10 copies Stabilizers 5 copies Heavy metal ion stabilizers 1 copy dispersant 1 copy water 10 copies

[0091] The silica-alumina modifier consists of: 10 parts steel slag incinerator slag, 5 parts metakaolin, 3 parts diorite powder, and 1 part sodium silicate; the stabilizer consists of: 10 parts zeolite powder, 5 parts diatomite, and 3 parts talc powder; the heavy metal ion stabilizer is aluminum hydroxide; and the dispersant is sodium tripolyphosphate.

[0092] The preparation method of the above-mentioned manganese slag red mud composite stabilized soil is as follows:

[0093] 1) The electrolytic manganese slag is pretreated by water washing and ammonium salt precipitation. The specific operation is as follows: the manganese slag is dissolved in an acidic solution, ammonia is added to generate precipitable manganese ammonium salt, supersaturated salts are added to the solution to precipitate the manganese ammonium salt, the precipitate is separated, and the moisture content of the residue is controlled at 20-28%; the red mud is pretreated by pressure filtration and the moisture content is controlled at 25-35%.

[0094] 2) The pretreated electrolytic manganese slag is mixed with red mud, dispersant, and heavy metal ion stabilizer using a forced mixer. The mixing speed is 10-20 rpm and the mixing time is 5-7 minutes. The mixture is then allowed to stand for 8 hours to obtain the mixture.

[0095] 3) Add quicklime, phosphogypsum, silica-alumina modifier, stabilizer and water to the mixture, and mix using a forced mixer at a speed of 10-20 rpm for 5-7 minutes to obtain manganese slag red mud composite stabilized soil.

[0096] Example 3

[0097] A manganese slag red mud composite stabilized soil, comprising components in parts by weight:

[0098] Electrolytic manganese slag 70 copies Red mud 40 copies quicklime 10 copies phosphogypsum 15 copies Silicon-aluminum modifier 15 copies Stabilizers 10 copies Heavy metal ion stabilizers 5 copies dispersant 3 copies water 25 copies

[0099] The silica-alumina modifier consists of: 10 parts steel slag incinerator slag, 5 parts metakaolin, 3 parts diorite powder, and 1 part sodium silicate; the stabilizer consists of: 10 parts zeolite powder, 5 parts diatomite, and 3 parts talc powder; the heavy metal ion stabilizer is aluminum hydroxide; and the dispersant is sodium tripolyphosphate.

[0100] The preparation method of the above-mentioned manganese slag red mud composite stabilized soil is as follows:

[0101] 1) The electrolytic manganese slag is pretreated by water washing and ammonium salt precipitation. The specific operation is as follows: the manganese slag is dissolved in an acidic solution, ammonia is added to generate precipitable manganese ammonium salt, supersaturated salts are added to the solution to precipitate the manganese ammonium salt, the precipitate is separated, and the moisture content of the residue is controlled at 20-28%; the red mud is pretreated by pressure filtration and the moisture content is controlled at 25-35%.

[0102] 2) The pretreated electrolytic manganese slag is mixed with red mud, dispersant, and heavy metal ion stabilizer using a forced mixer. The mixing speed is 10-20 rpm and the mixing time is 5-7 minutes. The mixture is then allowed to stand for 8 hours to obtain the mixture.

[0103] 3) Add quicklime, phosphogypsum, silica-alumina modifier, stabilizer and water to the mixture, and mix using a forced mixer at a speed of 10-20 rpm for 5-7 minutes to obtain manganese slag red mud composite stabilized soil.

[0104] Example 4

[0105] A manganese slag red mud composite stabilized soil, comprising components in parts by weight:

[0106] Electrolytic manganese slag 55 copies Red mud 40 copies quicklime 8 copies phosphogypsum 10 copies Silicon-aluminum modifier 10 copies Stabilizers 5 copies Heavy metal ion stabilizers 5 copies dispersant 3 copies water 20 copies

[0107] The silica-alumina modifier consists of: 10 parts steel slag incinerator slag, 5 parts metakaolin, 3 parts diorite powder, and 1 part sodium silicate; the stabilizer consists of: 10 parts zeolite powder, 5 parts diatomite, and 3 parts talc powder; the heavy metal ion stabilizer is aluminum hydroxide; and the dispersant is sodium tripolyphosphate.

[0108] The preparation method of the above-mentioned manganese slag red mud composite stabilized soil is as follows:

[0109] 1) The electrolytic manganese slag is pretreated by water washing and ammonium salt precipitation. The specific operation is as follows: the manganese slag is dissolved in an acidic solution, ammonia is added to generate precipitable manganese ammonium salt, supersaturated salts are added to the solution to precipitate the manganese ammonium salt, the precipitate is separated, and the moisture content of the residue is controlled at 20-28%; the red mud is pretreated by pressure filtration and the moisture content is controlled at 25-35%.

[0110] 2) The pretreated electrolytic manganese slag is mixed with red mud, dispersant, and heavy metal ion stabilizer using a forced mixer. The mixing speed is 10-20 rpm and the mixing time is 5-7 minutes. The mixture is then allowed to stand for 8 hours to obtain the mixture.

[0111] 3) Add quicklime, phosphogypsum, silica-alumina modifier, stabilizer and water to the mixture, and mix using a forced mixer at a speed of 10-20 rpm for 5-7 minutes to obtain manganese slag red mud composite stabilized soil.

[0112] Comparative Example 1

[0113] A manganese slag red mud composite stabilized soil, comprising components in parts by weight:

[0114] Electrolytic manganese slag 70 copies Red mud 40 copies cement 10 copies dispersant 2 copies water 15 copies

[0115] The dispersant is sodium tripolyphosphate.

[0116] The preparation method of the above-mentioned manganese slag red mud composite stabilized soil is as follows:

[0117] 1) The electrolytic manganese slag is pretreated by water washing and ammonium salt precipitation. The specific operation is as follows: the manganese slag is dissolved in an acidic solution, ammonia is added to generate precipitable manganese ammonium salt, supersaturated salts are added to the solution to precipitate the manganese ammonium salt, the precipitate is separated, and the moisture content of the residue is controlled at 20-28%; the red mud is pretreated by pressure filtration and the moisture content is controlled at 25-35%.

[0118] 2) The pretreated electrolytic manganese slag, red mud, and dispersant are mixed using a forced mixer at a speed of 10-20 rpm for 5-7 minutes. The mixture is then allowed to stand for 8 hours to obtain the mixture.

[0119] 3) Add cement and water to the mixture and mix using a forced mixer at a speed of 10-20 rpm for 5-7 minutes to obtain manganese slag red mud composite stabilized soil.

[0120] Comparative Example 2

[0121] A manganese slag red mud composite stabilized soil, comprising components in parts by weight:

[0122]

[0123]

[0124] The stabilizing agent consists of 10 parts zeolite powder, 5 parts diatomaceous earth, and 3 parts talc powder; the heavy metal ion stabilizer is aluminum hydroxide; and the dispersant is sodium tripolyphosphate.

[0125] The preparation method of the above-mentioned manganese slag red mud composite stabilized soil is as follows:

[0126] 1) The electrolytic manganese slag is pretreated by water washing and ammonium salt precipitation. The specific operation is as follows: the manganese slag is dissolved in an acidic solution, ammonia is added to generate precipitable manganese ammonium salt, supersaturated salts are added to the solution to precipitate the manganese ammonium salt, the precipitate is separated, and the moisture content of the residue is controlled at 20-28%; the red mud is pretreated by pressure filtration and the moisture content is controlled at 25-35%.

[0127] 2) The pretreated electrolytic manganese slag is mixed with red mud, dispersant and heavy metal ion stabilizer using a forced mixer. The mixing speed is 10-20 rpm and the mixing time is 5-7 minutes. The mixture is then left to stand for 8 hours to obtain the mixture.

[0128] 3) Add quicklime, phosphogypsum, stabilizing agent and water to the mixture, and mix using a forced mixer at a speed of 10-20 rpm for 5-7 minutes to obtain manganese slag red mud composite stabilized soil.

[0129] Comparative Example 3

[0130] A manganese slag red mud composite stabilized soil, comprising components in parts by weight:

[0131] Electrolytic manganese slag 60 copies Red mud 30 copies quicklime 8 copies phosphogypsum 12 copies Silicon-aluminum modifier 12 copies Heavy metal ion stabilizers 5 copies dispersant 3 copies water 15 copies

[0132] The silicon-aluminum modifier consists of: 10 parts steel slag incinerator slag, 5 parts metakaolin, 3 parts diorite powder, and 1 part sodium silicate; the heavy metal ion stabilizer is aluminum hydroxide; and the dispersant is sodium tripolyphosphate.

[0133] The preparation method of the above-mentioned manganese slag red mud composite stabilized soil is as follows:

[0134] 1) The electrolytic manganese slag is pretreated by water washing and ammonium salt precipitation. The specific operation is as follows: the manganese slag is dissolved in an acidic solution, ammonia is added to generate precipitable manganese ammonium salt, supersaturated salts are added to the solution to precipitate the manganese ammonium salt, the precipitate is separated, and the moisture content of the residue is controlled at 20-28%; the red mud is pretreated by pressure filtration and the moisture content is controlled at 25-35%.

[0135] 2) The pretreated electrolytic manganese slag is mixed with red mud, dispersant and heavy metal ion stabilizer using a forced mixer. The mixing speed is 10-20 rpm and the mixing time is 5-7 minutes. The mixture is then left to stand for 8 hours to obtain the mixture.

[0136] 3) Add quicklime, phosphogypsum, silica-alumina modifier and water to the mixture, and mix using a forced mixer at a speed of 10-20 rpm for 5-7 minutes to obtain manganese slag red mud composite stabilized soil.

[0137] Performance testing

[0138] 1. Construction:

[0139] (1) Construction method: road mixing method.

[0140] (2) Implementation Standards: Construction Requirements and Technical Specifications: JTG / D30-2015 Highway Subgrade Design Specifications;

[0141] JTG / TF20-2015 Technical Specifications for Highway Pavement Base Construction.

[0142] (3) Specific steps:

[0143] 1) The electrolytic manganese slag is pretreated by water washing and ammonium salt precipitation, and the moisture content of the residue is controlled to be 20-28%; the red mud is pretreated by pressure filtration, and the moisture content is controlled to be 25-35%.

[0144] 2) The pretreated electrolytic manganese slag is mixed with red mud, dispersant, and heavy metal ion stabilizer using a forced mixer and left to stand for 6-10 hours to obtain a mixture;

[0145] 3) Spread the mixture on the road surface, add quicklime, phosphogypsum, silica-alumina modifier, stabilizer and water to the surface, and mix it with a road mixer at a working speed of 2 to 3.3 km / h, a mixing width of 2400 mm and a mixing depth of 0 to 400 mm.

[0146] 4) Compaction is carried out by a road roller. The road roller travel speed is 3km / h, the compaction method is vibratory compaction, the compaction procedure is steady pressure - light vibratory rolling - heavy vibratory rolling, the number of compaction times is 3 to 5, the vibration frequency is 5 to 30Hz, and the vibration force is 600 to 800kg.

[0147] 5) Cover with geomembrane and geotextile for curing. The curing temperature is 20℃ and the humidity is 90%.

[0148] 2. Testing Standards:

[0149] The following performance tests were all performed in accordance with the standard: JTG3040-2020 Highway Geotechnical Test Procedure.

[0150] 3. Test Results:

[0151] The performance test results of the manganese slag red mud composite stabilized soils prepared in Examples 1-4 and Comparative Examples 1-3 are shown in Table 1.

[0152] Table 1. Performance test results of manganese slag and red mud composite stabilized soil

[0153]

[0154]

[0155] Table 1 shows the performance test results of the manganese slag and red mud composite stabilized soil. As can be seen from Table 1, the manganese slag and red mud composite stabilized soils in Examples 1-4 have a resilient modulus as high as 123 MPa, indicating good elastic recovery performance and strong resistance to deformation and recovery; the 7-day compressive strength is ≥1.15 MPa, showing high compressive strength; and the 28-day water-soaked retention strength reaches over 82%, indicating minimal dissolution of hydration products and cementitious materials during water immersion, resulting in good water erosion resistance and resistance to disintegration upon contact with water. Therefore, the manganese slag and red mud composite stabilized soil prepared using the components and preparation method provided by this invention exhibits good overall stability.

[0156] In Comparative Example 1, cement was added to consolidate electrolytic manganese slag and red mud. Although cement, as a commonly used binder for inorganic binders, can also play a consolidation role, there is no synergistic reaction between cement and electrolytic manganese slag and red mud, which significantly reduces the resilient modulus and compressive strength of the composite stabilized soil.

[0157] In Comparative Example 2, no silicon-aluminum modifier was added, and the calcium-silicon ratio of the raw material system was not optimized, resulting in a poor activation effect of manganese slag and red mud, and a significant deterioration in the overall performance of the material, such as compressive strength.

[0158] In Comparative Example 3, no stabilizing agent was added, which resulted in the gradation of electrolytic manganese slag and red mud not being optimized during mixing and compaction. As a result, the particles could not be fully interlocked during compaction, leading to a decrease in the strength and stability of the material.

[0159] The manganese slag and red mud composite stabilized soil provided by this invention utilizes a large amount of solid waste such as electrolytic manganese slag and red mud, realizing the resource utilization of solid waste, saving raw material costs, and reducing construction costs when combined with road mixing methods. The manganese slag and red mud composite stabilized soil has high compressive strength, strong resistance to deformation and recovery, and strong resistance to water erosion. Under environmental conditions such as humidity changes and water erosion, it exhibits good overall stability and durability. Therefore, the manganese slag and red mud composite stabilized soil provided by this invention can have excellent application effects in road construction or infrastructure development.

Claims

1. A manganese slag red mud composite stabilized soil, characterized in that, It is prepared from water and solid components; by mass, the composition of the solid components is as follows: 55-70 parts of electrolytic manganese slag, 20-40 parts of red mud, 5-10 parts of quicklime, 8-15 parts of phosphogypsum, 10-15 parts of silicon-aluminum modifier, 5-10 parts of stabilizing agent, 1-5 parts of heavy metal ion stabilizer, and 1-3 parts of dispersant. The silicon-aluminum modifier is selected from at least one of steel slag, waste incinerator slag, non-ferrous metallurgical slag, metakaolin, and diorite powder; the silicon-aluminum modifier adjusts the calcium-silicon ratio of the system to be 0.6~1.5 and the silicon-aluminum ratio to be ≥2. The stabilizing agent includes at least one of zeolite powder, diatomaceous earth, vermiculite powder, talc powder, shale powder, and fly ash.

2. The manganese slag red mud composite stabilized soil according to claim 1, characterized in that, The electrolytic manganese slag comprises the following chemical components by mass percentage: 8.5-9.2% CaO, 33-35% SiO2, 5-6.5% Al2O3, 18-22% Fe2O3, 7.5-8% MnO, and 19-23% SO3; And / or, the moisture content of the electrolytic manganese slag is 22-28%; And / or, the particle size of the electrolytic manganese slag is 2.5~6.5μm; And / or, the particle size of the electrolytic manganese slag is concentrated in the range of <3.0 μm, accounting for 65~75%; And / or, the pH value of the electrolytic manganese slag leachate is 5.3~6.

6.

3. The manganese slag red mud composite stabilized soil according to claim 1, characterized in that, The red mud comprises the following chemical components by mass percentage: 10.31~12.15% SiO2, 19.54~21.67% Al2O3, 36.21~41.58% Fe2O3, 14.57~16.80% NaOH, 1.58~3.05% CaO, 7.33~8.50% Na2O, 5.25~6.20% TiO2, and 0.16~0.35% MgO; And / or, the red mud includes the following mineral components: aragonite, calcite, opal, gibbsite, and goethite; And / or, the mineral composition of the red mud contains 55-70% sulphite and calcite; And / or, the specific gravity of the red mud is 2.7 to 2.9; And / or, the dry density of the red mud is ≤1.3 g / cm³. 3 ; And / or, the water content of the red mud is 25-35%; And / or, the liquid limit of the red mud is 40-49%; And / or, the plastic limit of the red mud is 30-35%; And / or, the pH value of the red mud is 10.5~12.

0.

4. The manganese slag red mud composite stabilized soil according to claim 1, characterized in that, The apparent density of the silicon-aluminum modifier is 2.6~2.9 g / cm³. 3 ; And / or, the specific surface area of ​​the silicon-aluminum modifier is 350~400m². 2 / kg.

5. The manganese slag red mud composite stabilized soil according to claim 1, characterized in that, The heavy metal ion stabilizer includes at least one of metal hydroxide stabilizers, organic chelating agents, and phosphate stabilizers.

6. The manganese slag red mud composite stabilized soil according to claim 1, characterized in that, The dispersant is selected from phosphate dispersants.

7. A manganese slag red mud composite stabilized soil according to any one of claims 1 to 6, characterized in that, The mass ratio of water to the total mass of solid components is 1:(4~11).

8. A method for preparing manganese slag red mud composite stabilized soil according to any one of claims 1 to 7, characterized in that, Includes the following steps: 1) Mix electrolytic manganese slag with red mud, dispersant, and heavy metal ion stabilizer, and let stand to obtain a mixture; 2) Add quicklime, phosphogypsum, silica-alumina modifier, stabilizer and water to the mixture, and mix to obtain manganese slag red mud composite stabilized soil.

9. The application of the manganese slag red mud composite stabilized soil according to any one of claims 1 to 7 in road or infrastructure construction.

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