Modified lepidolite slag roadbed filler and preparation method thereof

Abstract

The invention relates to a modified lepidolite slag roadbed filler and a preparation method thereof, and belongs to the technical field of roadbed engineering. The modified lepidolite slag roadbed filler comprises the following components in parts by weight: 74-80 parts of lepidolite slag, 0.8-1.2 parts of potassium ferrate powder, 1.5-2 parts of lime, 1.2-1.8 parts of a composite modified adsorption material, 1.5-3 parts of blast furnace slag powder and 14-18 parts of water. According to the modification principle, the utilization requirement of harmless engineering is met by utilizing the complementary chemical characteristic of materials such as the lepidolite slag and the inorganic modifier, so that the lepidolite slag is used for roadbed filling engineering, and the preparation process can effectively solve the problems that heat is rapidly released due to the lime hydration reaction and the volcanic ash reaction, the temperature is sharply increased and the construction cost is reduced. Therefore, the condition that the curing effect of the lepidolite slag roadbed filler is reduced is avoided. Through a unique material formula and a preparation process, the lepidolite slag is converted into a green and harmless roadbed material with stable pavement performance, and the roadbed material is used for road engineering construction.

Description

Technical Field

[0001] This invention belongs to the field of roadbed engineering technology, and specifically relates to a modified lithium mica slag roadbed filler and its preparation method. Background Technology

[0002] Lithium mica slag, a solid waste generated during lithium ore processing, contains various harmful ions and needs to be prepared as roadbed filler by adding solidifying materials such as lime and slag powder to achieve resource utilization. Traditional methods for preparing lithium mica slag roadbed filler employ lime stabilization technology, using the hydration and pozzolanic reactions of lime to generate cementitious substances that solidify the harmful ions. Continuous stirring is then used to thoroughly mix the solidified material with the lithium mica slag to improve solidification efficiency. However, the violent hydration reaction between lime and water releases a large amount of heat, and the lime hydration products react with the active aluminosilicates in the lithium mica slag in a pozzolanic reaction, further releasing heat. This causes the mixture temperature to rise sharply in a short period. Traditional continuous stirring cannot effectively dissipate heat, and the high temperature environment exacerbates moisture evaporation, leading to a rapid decrease in moisture content. The hydration and pozzolanic reactions are hampered by water shortage, hindering their full progress. Furthermore, the high temperature damages the structure of the already formed cementitious products, significantly reducing the solidification effect. In existing technologies, the lack of effective temperature control means prevents the temperature rise during the lime hydration and pozzolanic reactions from being suppressed. The mechanical heat generated by continuous stirring further exacerbates the temperature accumulation effect, causing the solidification reaction to deviate from the optimal temperature conditions. In other words, the existing technology has a technical problem where the heat released by the lime hydration reaction and the volcanic ash reaction causes a rapid rise in temperature, which reduces the solidification effect of the lithium mica slag roadbed filler. Summary of the Invention

[0003] In view of this, the present invention provides a modified lithium mica slag roadbed filler and its preparation method, which can solve the technical problem in the prior art where the heat released by lime hydration reaction and volcanic ash reaction causes a rapid temperature rise, resulting in a reduction in the solidification effect of lithium mica slag roadbed filler.

[0004] The present invention is achieved as follows: The first aspect of the present invention provides a modified lithium mica slag roadbed filler, which is composed of the following solid components in parts by mass: 74-80 parts of lithium mica slag, 0.8-1.2 parts of potassium ferrate powder, 1.5-2 parts of lime, 1.2-1.8 parts of composite modified adsorbent material, 1.5-3 parts of blast furnace slag powder, and 15-20 parts of water.

[0005] The lithium mica slag comprises the following chemical composition with the following oxide percentages: 25-40%. 18-22% 8-22% 9-14% The particle size is concentrated in the range of 0 to 5 mm, the non-uniformity coefficient is not less than 5, and the curvature coefficient is in the range of 1 to 3.

[0006] Among them, the potassium ferrate powder is effective The content is not less than 90%, the particle size range is between 75 and 150 μm, and the ferrate ions generated after potassium ferrate powder is dissolved in water have an effect on the lithium mica residue. and It undergoes an oxidation reaction.

[0007] The lime contains at least 78% effective calcium oxide and magnesium oxide, and has a fineness of 0.08 mm with a pass rate of more than 85%. The calcium oxide in the lime is hydrated to generate calcium hydroxide and provides hydroxide ions.

[0008] The composite modified adsorbent material is composed of hydroxyl iron-aluminum composite oxides, with hydroxyl iron oxide accounting for 0.8%–1.2% by mass and hydroxyl aluminum oxide accounting for 0.4%–0.6% by mass, and has a specific surface area of ​​not less than 200. .

[0009] The second aspect of this invention provides a method for preparing modified lepidolite slag roadbed filler, comprising the following steps: weighing lepidolite slag, potassium ferrate powder, lime, composite modified adsorbent material, and blast furnace slag powder, and dry mixing them to obtain modified lepidolite slag roadbed dry mix; conducting a compaction test on the modified lepidolite slag roadbed dry mix to determine the maximum dry density and optimum moisture content, and recording the temperature change curve of the mixture; weighing potassium ferrate powder according to a ratio and adding it to the lepidolite slag for the first stirring; adding water to the mixture three times according to the optimum moisture content ratio and performing a steaming treatment; after the steaming is completed, measuring the actual moisture content and temperature of the wet lepidolite slag material, and performing [further processing] based on the measurement results. Atomized spraying for water replenishment or pre-cooling with cooling water was used. Lime and composite modified adsorbent were weighed according to the proportion and added to the wet lithium mica slag material by intermittent stirring. The intermittent stirring pause time adjustment coefficient and stirring time adjustment coefficient were determined by the intermittent stirring parameter calibration experiment. The actual intermittent stirring pause time and actual stirring time were calculated according to the intermittent stirring parameter calculation function. Blast furnace slag powder was weighed according to the proportion and dissolved in water to prepare slag powder suspension. The slag powder suspension was added to the mixture in batches using a batch feeding optimization scheduling strategy. After all materials were mixed, the temperature rise rate and water loss rate of the mixture were measured, and a hydration reaction control game model was established for two-layer optimization.

[0010] Among them, the water The value is 6.5-9, water A value below 6.5 negatively impacts the co-precipitation and stabilization / solidification reactions, affecting the water's... A value higher than 9 intensifies the decomposition reaction of potassium ferrate.

[0011] The aforementioned braising process allows water to fully permeate the lithium mica residue particles, thereby reducing the amount of water in the lithium mica residue. and It comes into full contact with ferrate ions and undergoes an oxidation reaction; the simmering time is 5–8 hours.

[0012] The atomized spray water replenishment uses an atomizing nozzle with a nozzle orifice diameter of 0.3–0.5 mm and a spray pressure of 0.2–0.4 mm. The spraying time is 30-60 seconds. The atomized spraying water replenishment disperses the water evenly on the surface of the mixture in the form of fine droplets.

[0013] The cooling water pre-cooling treatment uses cooling water at a temperature of 5-15°C instead of room temperature water for subsequent water addition operations. The cooling water reduces the rate of temperature rise of the mixture by absorbing the heat released by the lime hydration reaction and the volcanic ash reaction.

[0014] The intermittent stirring method involves setting a cycle of alternating stirring and stopping. During the stirring phase, lime and composite modified adsorbent materials are fully mixed with the wet lithium mica slag. During the stopping phase, the internal temperature of the mixture is reduced through natural heat dissipation.

[0015] Specifically, the intermittent stirring parameter calibration experiment involves setting 5 different initial intermittent stirring pause times and 5 different initial stirring times. A stirring experiment is conducted on each combination of initial intermittent stirring pause time and initial stirring time, and the temperature peak and temperature uniformity of the mixture are measured during the stirring process. The optimal initial intermittent stirring pause time and the optimal initial stirring time are determined based on the experimental group with the lowest temperature peak and the highest temperature uniformity among the 25 experimental data sets.

[0016] The intermittent stirring parameter calculation function calculates the actual intermittent stirring pause time and the actual stirring time based on the temperature monitoring value and actual moisture content of the wet lithium mica slag. When the temperature monitoring value of the wet lithium mica slag increases, the actual intermittent stirring pause time is extended, and when the actual moisture content of the wet lithium mica slag decreases, the actual stirring time is shortened.

[0017] This invention uses lepidolite slag, potassium ferrate powder, lime, composite modified adsorbent material, blast furnace slag powder, and water as basic raw materials to generate a highly crystalline product that can fill the voids between lithium slag particles, optimize structural density, and reduce the risk of leaching of characteristic pollutants from the lepidolite slag. Furthermore, this invention replaces the traditional continuous stirring method with an intermittent stirring approach. During the stirring phase, the solidified material and lepidolite slag are thoroughly mixed. During the rest phase, natural heat dissipation is used to lower the temperature of the mixture, avoiding the continuous temperature accumulation caused by continuous stirring. Simultaneously, an intermittent stirring parameter calculation function is established to dynamically adjust the intermittent stirring rest time and stirring time based on temperature monitoring values ​​and moisture content. When the temperature rises, the rest time is extended to increase heat dissipation; when the moisture content decreases, the stirring time is shortened to reduce moisture evaporation. This invention further constructs a hydration reaction control game model consisting of an upper-level model aiming to maximize temperature uniformity and a lower-level model aiming to maximize moisture content stability. Through dual-layer optimization, it seeks the optimal balance between temperature and moisture control. The upper-level model optimizes the intermittent stirring pause time to achieve uniform temperature distribution, while the lower-level model optimizes the frequency of atomized spraying to maintain stable moisture content. The two models influence each other and optimize synergistically through coupling terms, ensuring that the hydration and pozzolanic reactions proceed fully under suitable temperature and moisture conditions. In summary, this invention, through the dual effects of intermittent stirring and the hydration reaction control game model, effectively controls the problem of excessive moisture evaporation caused by rapid heat release and sharp temperature rise during lime hydration and pozzolanic reactions, thus avoiding a decrease in the solidification effect of lithium mica slag roadbed filler.

[0018] This invention provides a modified lithium mica slag roadbed filler and its preparation method. The core objective is to transform industrial solid waste lithium mica slag into a high-performance roadbed engineering material. Through unique material proportioning and refined process control, this invention fundamentally solves the leaching pollution problem of characteristic pollutants in lithium mica slag. Simultaneously, by controlling the preparation process, it avoids engineering problems such as loose structure and uneven strength in modified lithium mica slag, ensuring that the resulting filler possesses excellent road performance. This not only provides a reliable solution for the large-scale utilization of lithium mica slag but also directly provides road engineering with a new type of roadbed material that is green, harmless, stable in performance, and cost-effective, demonstrating significant engineering application value and promising prospects for promotion. Attached Figure Description

[0019] Figure 1 This is a flowchart of the method of the present invention.

[0020] Figure 2 This is a graph showing the temperature change of the mixture in Example 2.

[0021] Figure 3 This is a temperature distribution evolution diagram of the intermittent stirring process in Example 2.

[0022] Figure 4 This is an optimized diagram of the batch feeding path for the slag powder suspension in Example 2.

[0023] Figure 5 This is the convergence graph of the two-layer optimization of the hydration reaction control game model in Example 2. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0025] The first aspect of this invention provides a modified lithium mica slag roadbed filler, which is composed of the following solid components in parts by mass: 72-80 parts lithium mica slag, 0.8-1.2 parts potassium ferrate powder, 1.5-2 parts lime, 1.2-1.8 parts composite modified adsorbent material, 1.5-3 parts blast furnace slag powder, and 14-18 parts water.

[0026] Further specified, the lithium mica slag comprises the following chemical composition in percentage of oxides: 25-40% SiO2, 18-22% Al2O3, 8-22% CaO, and 9-14% SO3;

[0027] Lithium mica residue, as an industrial waste, contains a large amount of silica and alumina. It has high compaction strength and low volume change rate upon contact with water, making it effective in improving the overall stability of roadbeds when used as a filler. Furthermore, lithium mica residue also contains some sulfates, which can react with high-alumina, high-calcium materials and its own calcium oxide to form hydrated calcium sulfoaluminate and hydrated calcium silicate gels. This further optimizes the aggregate interface, resulting in a denser structure and reduced leaching of harmful substances.

[0028] Further specified, the particle size of the lithium mica slag is concentrated in the range of 0 to 5 mm, its non-uniformity coefficient should not be less than 5, and its curvature coefficient should be in the range of 1 to 3;

[0029] Lithium mica slag is the skeleton carrier and basic raw material of filler. The slag particles are sub-nanometer in size and have many pores between them. By controlling its non-uniformity coefficient to be no less than 5 and its curvature coefficient to be within the range of 1 to 3, it can achieve better compaction during rolling, thereby increasing the strength and stability of the roadbed.

[0030] Further specified, the potassium ferrate powder contains ≥90% effective K2FeO4 and has a particle size range of 75–150 μm.

[0031] Further specified, the effective calcium oxide and magnesium oxide content in the lime is ≥78%, and the fineness passing rate of 0.08mm is greater than 85%.

[0032] Further specified, the composite modified adsorbent material is composed of hydroxyl iron-aluminum composite oxides, wherein the mass percentage of hydroxyl iron oxide is 0.8%-1.2% and the mass percentage of hydroxyl aluminum oxide is 0.4%-0.6%. Specific surface area ≥200 m² / g.

[0033] Further specifying, the blast furnace slag powder is S95 grade blast furnace slag powder.

[0034] To address the leaching pollution caused by beryllium, thallium, manganese, and fluorides in lepidolite slag, this invention modifies it by adding potassium ferrate powder, lime, a composite modified adsorbent, and blast furnace slag powder. Specifically, the ferrate ions obtained by dissolving potassium ferrate powder in water can oxidize Mn²⁺ and Tl⁺ in lepidolite slag to Mn. 4 ⁺ and Tl 3 ⁺, and generates MnO2 and Tl(OH)3 precipitates, which are then reduced to Fe(OH)3 colloids with flocculation properties, and the decomposition products pose no risk of secondary pollution. The calcium hydroxide produced by the hydration of effective calcium oxide in lime can provide OH... - With oxidized Tl 3+ Be 2+ The reaction occurs, producing Be(OH)₂ and Tl(OH)₃ precipitates; the provided Ca 2+ It can also be used with F - The reaction produces CaF2 precipitate, which helps remove fluorides from the leachate; furthermore, lime provides the necessary alkaline environment for subsequent stabilization and solidification reactions. The composite modified adsorbent material is composed of a hydroxyl-iron-aluminum composite oxide. The hydroxyl groups (-OH) on the surface of this oxide can interact with F⁻ through ion exchange to form more stable Fe-F and Al-F covalent bonds, further reducing the fluoride leaching content; the Al in the hydroxyl-aluminum octahedral lattice... 3+ It can undergo isomorphous substitution with incompletely precipitated Be²⁺, fixing Be²⁺ in the crystal lattice; Fe in iron hydroxyoxide 3+ This not only further promotes the full oxidation of Mn²⁺ and Tl⁺, but also allows (-OH) to form stable Fe-O-Mn and Fe-O-Tl complexes with the aforementioned oxidation products. Furthermore, the negatively charged sites on the surface of the hydroxyl oxide exhibit electrostatic adsorption of Be²⁺, Mn²⁺, and Tl⁺. As a low-cost industrial byproduct, blast furnace slag powder contains vitreous active components that can undergo hydration reactions with aluminosilicates in lime and lepidolite slag to generate cementitious phases such as CSH and CAH. The resulting dense cemented layer further restricts the leaching of characteristic pollutants, reducing the risk of pollution.

[0035] Further specified, the pH of the water is 6 to 9.

[0036] If the pH of the water is too low (acidic), it will affect the co-precipitation and stabilization of the mixture; if the pH of the water is too high (alkaline), it will intensify the oxidation reaction between potassium ferrate and water, limiting its effect on Mn. 2+ 、Tl + The oxidation effect.

[0037] The minimum bearing ratio of modified lithium mica slag roadbed filler should meet the requirements of the current "Highway Roadbed Design Specification" (JTGD30); the compaction degree of modified lithium mica slag roadbed should meet the requirements of Table 1.

[0038] Table 1: Compaction Degree of Modified Lithium Mica Slag Subgrade

[0039] Note: The compaction degrees listed in the table are the compaction degrees corresponding to the maximum dry density obtained from the heavy compaction test according to the current "Highway Geotechnical Test Procedure" (JTG 3430).

[0040] like Figure 1 The diagram shown is a flowchart of a method for preparing modified lithium mica slag roadbed filler provided by the second aspect of the present invention. This method includes the following steps:

[0041] S01. Weigh 74-80 parts of lithium mica slag, 0.8-1.2 parts of potassium ferrate powder, 1.5-2 parts of lime, 1.2-1.8 parts of composite modified adsorbent material, and 1.5-3 parts of blast furnace slag powder and dry mix them to obtain modified lithium mica slag roadbed dry mix.

[0042] S02. Compaction tests were conducted on the modified lithium mica slag roadbed dry mix to determine the maximum dry density and optimum moisture content, and the temperature change curve of the mix was recorded.

[0043] S03. Weigh out potassium ferrate powder according to the proportion and add it to the lithium mica residue for the first stirring. The stirring time is 3-5 minutes and the stirring speed is 30-50 r / min.

[0044] S04. Add water to the mixture described in step S03 in three steps according to the optimal moisture content ratio. Each time, the amount of water added is one-third of the total water volume. Stir for 2-3 minutes after each addition of water. After all the water has been added, perform a simmering process for 5-8 hours.

[0045] S05. After the simmering process is completed, the actual moisture content and temperature of the wet lithium mica residue are measured. When the ratio of the actual moisture content to the optimum moisture content is <0.85, atomized spraying is used to replenish the water.

[0046] S06. Weigh lime and composite modified adsorbent material according to the proportion, and add them to the wet lithium mica slag described in step S05 by intermittent stirring. Determine the intermittent stirring pause time adjustment coefficient and stirring time adjustment coefficient through intermittent stirring parameter calibration experiment. Calculate the actual intermittent stirring pause time and actual stirring time according to the intermittent stirring parameter calculation function. The intermittent stirring cycle is the actual stirring time followed by the actual intermittent stirring pause time. The total stirring time shall not be less than 8 minutes.

[0047] S07. Weigh out blast furnace slag powder according to the proportion and dissolve it in 15-20 parts of water to prepare slag powder suspension. Use a batch feeding optimization scheduling strategy to determine the order of adding slag powder suspension and the amount added in each batch. Add the slag powder suspension to the mixture described in step S06 in batches, and stir for 1-2 minutes after each addition.

[0048] S08. After all materials are mixed, the temperature rise rate and water loss rate of the mixture are measured. A game model for controlling the hydration reaction is established for two-layer optimization. When the temperature rise rate is >8℃ / min, the intermittent stirring pause time is increased to 2min. When the water loss rate is >0.5% / min, the frequency of atomized spray water replenishment is increased to obtain modified lithium mica slag roadbed filler.

[0049] The lithium mica slag comprises the following chemical composition with the following oxide percentages: 25-40%. 18-22% 8-22% 9-14% The particle size is concentrated in the range of 0 to 5 mm, the non-uniformity coefficient is not less than 5, and the curvature coefficient is in the range of 1 to 3.

[0050] Among them, the potassium ferrate powder is effective The content is not less than 90%, and the particle size ranges from 75 to 150 μm. The ferrate ions generated when potassium ferrate powder dissolves in water affect the ferrate ions in lepidolite slag. and To carry out an oxidation reaction, Oxidized to And generate Precipitation, Oxidized to And generate Precipitation occurs when the ferrate ions are reduced to... It acts as a colloid and plays a flocculation role.

[0051] The lime contains at least 78% effective calcium oxide and magnesium oxide, and has a 0.08mm fineness passing rate greater than 85%. The calcium oxide in the lime hydrates to form calcium hydroxide, and the hydroxide ions provided by the calcium hydroxide react with the oxidized calcium hydroxide... and A precipitation reaction occurs, producing and Precipitation; provided by calcium hydroxide Reacts with fluoride ions to produce precipitation.

[0052] The composite modified adsorbent material is composed of hydroxyl iron-aluminum composite oxides, with hydroxyl iron oxide accounting for 0.8%–1.2% by mass and hydroxyl aluminum oxide accounting for 0.4%–0.6% by mass, and has a specific surface area of ​​not less than 200. The hydroxyl groups on the surface of the composite modified adsorbent material form iron-fluorine and aluminum-fluorine coordination bonds with fluoride ions through ion exchange; the hydroxyl groups in the octahedral lattice of alumina... and Isomorphic substitution reaction occurs; in iron hydroxyoxide Promote and The oxidation reaction results in the formation of iron-manganese complexes and iron-thallium complexes by the hydroxyl groups and the oxidation products.

[0053] The blast furnace slag powder is S95 grade blast furnace slag powder. The vitreous active components in the blast furnace slag powder undergo a hydration reaction with the aluminosilicates in lime and lepidolite slag to generate calcium silicate hydration gel and calcium aluminate hydration gel, forming a dense cemented layer.

[0054] Among them, the water The value is 6.5–9. (Water) A value below 6.5 negatively impacts the co-precipitation and stabilization / solidification reactions; water... Values ​​above 9 intensify the decomposition reaction of potassium ferrate and reduce its effectiveness. and The oxidation efficiency.

[0055] The aforementioned braising process allows water to fully permeate the lithium mica residue particles, thereby reducing the amount of water in the lithium mica residue. and When the potassium ferrate comes into full contact with ferrate ions and undergoes an oxidation reaction, the oxidation reaction is insufficient when the simmering time is less than 5 hours, and excessive decomposition of potassium ferrate when the simmering time exceeds 8 hours, which leads to a decrease in oxidation efficiency.

[0056] The atomized spray water replenishment uses an atomizing nozzle with a nozzle orifice diameter of 0.3–0.5 mm and a spray pressure of 0.2–0.4 mm. The duration of a single spray is 30–60 seconds. Atomized spraying distributes water evenly onto the surface of the mixture in the form of fine droplets, preventing excessive local moisture from causing the mixture to clump.

[0057] Optionally, in S05, a pre-cooling treatment with cooling water is also included when the temperature is >55℃; wherein, the pre-cooling treatment with cooling water at a temperature of 5 to 25℃ is used instead of room temperature water for subsequent water addition operations, and the cooling water reduces the amount of moisture evaporation of the mixture by absorbing the heat released by the lime hydration reaction and the volcanic ash reaction.

[0058] The intermittent stirring method involves setting a cycle of alternating stirring and stopping. During the stirring phase, lime and composite modified adsorbent materials are fully mixed with the wet lithium mica slag. During the stopping phase, the internal temperature of the mixture is reduced through natural heat dissipation, thus avoiding the temperature accumulation effect caused by continuous stirring.

[0059] The intermittent stirring parameter calibration experiment includes the following operations: setting 5 different initial intermittent stirring pause times of 0.5 min, 1 min, 1.5 min, 2 min, and 2.5 min, and setting 5 different initial stirring times of 1 min, 1.5 min, 2 min, 2.5 min, and 3 min, respectively. A stirring experiment is conducted on each combination of initial intermittent stirring pause time and initial stirring time. The peak temperature and temperature uniformity of the mixture during stirring are measured, and 25 sets of experimental data are recorded. The peak temperature is the maximum temperature of the mixture during stirring, and the temperature uniformity is the reciprocal of the standard deviation of the temperature at each monitoring point of the mixture at the end of stirring. Based on the experimental group with the lowest peak temperature and the highest temperature uniformity among the 25 sets of experimental data, the optimal initial intermittent stirring pause time and the optimal initial stirring time are determined, and the intermittent stirring pause time adjustment coefficient and the stirring time adjustment coefficient are calculated. The intermittent stirring parameter calibration experiment, through systematic parameter combination testing, establishes a quantitative relationship between the initial intermittent stirring pause time and the initial stirring time and the temperature control effect of the mixture, providing experimental basis for the adjustment coefficients of the subsequent intermittent stirring parameter calculation function.

[0060] The intermittent stirring pause time adjustment coefficient is calculated by dividing the optimal initial intermittent stirring pause time by 1 min, and the stirring time adjustment coefficient is calculated by dividing the optimal initial stirring time by 2 min. The intermittent stirring pause time adjustment coefficient and the stirring time adjustment coefficient are used to calculate the actual intermittent stirring pause time and the actual stirring time in the intermittent stirring parameter calculation function.

[0061] The intermittent stirring parameter calculation function is used to calculate the actual intermittent stirring pause time and actual stirring time based on the temperature monitoring value and actual moisture content of the wet lithium mica residue. The inputs include the temperature monitoring value of the wet lithium mica residue, the actual moisture content of the wet lithium mica residue, the intermittent stirring pause time adjustment coefficient, and the stirring time adjustment coefficient. The output is the actual intermittent stirring pause time and actual stirring time. The intermittent stirring parameter calculation function is described as follows: , ,in This refers to the actual intermittent stirring pause time, in minutes. The baseline intermittent stirring pause time is set to 1 minute. This is an adjustment coefficient for the intermittent stirring pause time. The temperature monitoring value of the wet lithium mica residue is in °C. This is a temperature reference value, taken as 25℃. The actual moisture content of the wet lithium mica residue is expressed in %. The optimal moisture content is expressed as a percentage. This is the actual mixing time, in minutes. The baseline stirring time is 2 minutes. This is the stirring time adjustment coefficient. The intermittent stirring parameter calculation function dynamically adjusts the actual intermittent stirring pause time and the actual stirring time by using the ratio of the temperature monitoring value to the temperature reference value and the ratio of the actual moisture content to the optimum moisture content. When the temperature monitoring value of the wet lithium mica slag increases, the actual intermittent stirring pause time is extended to increase heat dissipation time; when the actual moisture content of the wet lithium mica slag decreases, the actual stirring time is shortened to reduce moisture evaporation.

[0062] The temperature rise rate is the increase in temperature of the mixture per unit time. A temperature rise rate greater than 8℃ / min indicates that the heat released by the lime hydration reaction and the volcanic ash reaction exceeds the natural heat dissipation rate, and it is necessary to extend the intermittent stirring pause time to increase the heat dissipation time.

[0063] The water loss rate is the percentage decrease in the moisture content of the mixture per unit time. A water loss rate greater than 0.5% / min indicates that the moisture in the mixture evaporates too quickly, and it is necessary to increase the frequency of atomized spraying to maintain a suitable moisture content in the mixture.

[0064] The slag powder suspension is prepared by mixing blast furnace slag powder and water at a mass ratio of 1:10 to 1:13 and stirring for 3 to 5 minutes. The slag powder particles in the slag powder suspension are evenly dispersed in the water. When the mixture is added in batches, the slag powder suspension is evenly distributed inside the mixture, avoiding uneven volcanic ash reaction caused by local enrichment of slag powder.

[0065] The batch feeding optimization scheduling strategy is based on the Traveling Salesman Problem (TSP) model. The surface of the mixture is divided into n feeding location nodes, where n is an integer from 5 to 10. Each feeding location node corresponds to a temperature monitoring point and a moisture content monitoring point. The shortest path is calculated by starting from the initial feeding point, sequentially visiting all feeding location nodes, and returning to the initial point, minimizing the total length of the distribution path of the slag powder suspension on the surface of the mixture. The objective function of the TSP model is to minimize the total path length, with the constraint that each feeding location node is visited only once. The path planning results determine the order of adding the slag powder suspension. The amount added in each batch is dynamically adjusted based on the temperature and moisture content monitoring values ​​of the corresponding feeding location nodes. Feeding location nodes with higher temperature monitoring values ​​receive a smaller amount of feed, while feeding location nodes with lower moisture content monitoring values ​​receive a larger amount of feed. The batch feeding optimization scheduling strategy optimizes the spatial distribution path of slag powder suspension by using a traveling salesman problem model. While ensuring that slag powder is uniformly obtained at all locations on the surface of the mixture, it minimizes the movement distance during the feeding process, improves feeding efficiency, and reduces the differences in local volcanic ash reaction intensity.

[0066] The hydration reaction control game model includes an upper-level model aiming to maximize temperature uniformity and a lower-level model aiming to maximize moisture content stability. The objective function of the upper-level model maximizes the uniformity of temperature distribution at each monitoring point of the mixture. Inputs include the temperature monitoring values ​​at each monitoring point, the intermittent stirring pause time, and the heat dissipation coefficient; the output is the optimized intermittent stirring pause time. The objective function of the lower-level model maximizes the stability of the mixture's moisture content over time. Inputs include the actual moisture content of the mixture, the frequency of atomized spray water replenishment, and the evaporation rate coefficient; the output is the optimized atomized spray water replenishment frequency. The objective function of the upper-level model is described as follows: ,in The standard deviation of temperature monitoring values ​​at each monitoring point is given in °C. This is a reference value for the standard deviation of temperature, and its value is 10℃. This refers to the intermittent stirring pause time, expressed in minutes. This is a reference value for the intermittent stirring pause time, and is taken as 1 minute. Moisture content deviation, in percentage. This is a reference value for moisture content deviation, and its value is 1%. The coupling coefficient is denoted as 0.3 to 0.5; the objective function of the lower-level model is expressed as follows: ,in The absolute value of the difference between the actual moisture content and the optimum moisture content of the mixture, expressed as a percentage. This is a reference value for the moisture content difference, and the value is taken as 2%. This refers to the frequency of water replenishment for atomized spraying, expressed in times per hour. This is a reference value for the frequency of water replenishment for atomized spraying, and is taken as 6 times / hour. The coupling coefficient is 0.2 to 0.4. The constraints of the upper-level model are: the intermittent stirring pause time ∈ [1, 3] min and the difference between the maximum and minimum temperature monitoring values ​​at each monitoring point ≤ 15℃. The constraints of the lower-level model are: the atomized spray water replenishment frequency ∈ [3, 12] times / h and the ratio of the actual moisture content of the mixture to the optimum moisture content ∈ [0.85, 1.15]. The hydration reaction control game model seeks the optimal balance between temperature control and moisture control through the mutual game between the upper-level model and the lower-level model. The upper-level model optimizes the intermittent stirring pause time to achieve uniform temperature distribution, and the lower-level model optimizes the atomized spray water replenishment frequency to maintain stable moisture content. The two models influence each other and optimize synergistically through coupling terms.

[0067] The heat dissipation coefficient is the ratio of the heat lost by the mixture through a unit area per unit time to the temperature difference. The heat dissipation coefficient is calculated using heat transfer formulas based on the thermal properties of the mixture and the ambient temperature. The heat dissipation coefficient is used to optimize the temperature uniformity in the objective function of the upper-level model.

[0068] The evaporation rate coefficient is the ratio of the mass of water evaporated per unit area per unit time to the moisture content of the mixture. The evaporation rate coefficient is calculated using the evaporation kinetics formula based on the surface area of ​​the mixture, ambient humidity, and temperature. The evaporation rate coefficient is used for the optimization calculation of moisture content stability in the objective function of the lower-level model.

[0069] The moisture content deviation is the average of the absolute values ​​of the differences between the actual moisture content of the mixture at each monitoring point and the average actual moisture content of the mixture at all monitoring points. The moisture content deviation reflects the degree of unevenness of the moisture content distribution within the mixture. The moisture content deviation appears as a coupling term in the objective function of the upper-level model to coordinate the mutual influence between temperature control and moisture control.

[0070] The standard deviation of the temperature monitoring value appears as a coupling term in the objective function of the lower-level model to coordinate the mutual influence between moisture control and temperature control. When the temperature distribution is uneven, the frequency of atomized spray water replenishment needs to be adjusted accordingly to avoid rapid evaporation of moisture in local overheated areas.

[0071] The specific implementation methods of the above steps are described in detail below.

[0072] The specific implementation of step S01 is as follows: First, an electronic scale is used to accurately weigh each component raw material. 74-80 parts of lithium mica slag are weighed as the main filler substrate, 0.8-1.2 parts of potassium ferrate powder are weighed as the oxidant component, 1.5-2 parts of lime are weighed as the alkaline activator, 1.2-1.8 parts of composite modified adsorbent material are weighed as the adsorption and solidification component, and 1.5-3 parts of blast furnace slag powder are weighed as the pozzolanic active component. Then, the weighed raw materials are put into a twin-shaft screw dry mixer for premixing. The dry mixing time is controlled at 5-8 minutes, and the stirring speed is controlled at 40-60 r / min. Low-speed stirring is used during the dry mixing process to avoid material dust and segregation. After the components are fully and evenly mixed in the dry mixer, the material is discharged to obtain the modified lithium mica slag roadbed dry mix. The purpose of this step is to initially mix the raw materials in a dry state, so that the potassium ferrate powder is evenly dispersed on the surface of the lithium mica slag particles, providing a sufficient contact interface for the subsequent oxidation reaction after water addition, while ensuring the uniform distribution of lime and composite modified adsorbent in the mixture, and avoiding local enrichment or depletion during the subsequent wet mixing process.

[0073] The specific implementation of step S02 is as follows: Following the compaction test method in the Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering, a heavy compactor is used to conduct compaction tests on the modified lithium mica slag roadbed dry mix. During the test, 5-7 different moisture content gradients are set, with 3 parallel samples prepared for each moisture content gradient. By measuring the dry density values ​​of the samples at different moisture contents, a curve showing the relationship between dry density and moisture content is plotted. The maximum dry density and optimum moisture content corresponding to the peak value of the curve are determined. Simultaneously, multi-point temperature sensors are used to monitor the temperature of the mixture in real time during the compaction test, recording the temperature change data from the start of water addition to the completion of compaction, and establishing a temperature-time curve. The purpose of this step is to determine the optimum moisture content parameter required for the mixture to reach maximum density through the compaction test, providing a precise basis for subsequent water addition operations. At the same time, temperature monitoring helps to understand the thermodynamic characteristics of the mixture during the wet mixing process, providing basic data support for the formulation of subsequent temperature control measures.

[0074] The specific implementation of step S03 is as follows: Weigh potassium ferrate powder according to the proportion determined in step S01, slowly add the potassium ferrate powder to the lepidolite slag, and perform the first mixing using a planetary mixer. During the mixing process, strictly control the mixing time to 3-5 minutes and the mixing speed to a low range of 30-50 r / min. The mixing blades adopt a spiral design to achieve vertical tumbling and radial mixing of the material. Maintain the relative humidity of the environment within the range of 40%-60% during the mixing process to prevent the potassium ferrate powder from absorbing moisture. After mixing, perform a uniformity test on the mixture. The uniformity of mixing is evaluated by taking samples from different locations in the mixture and measuring the coefficient of variation of the potassium ferrate content. The purpose of this step is to fully mix the potassium ferrate powder and the lepidolite slag in a dry state, so that the potassium ferrate powder is evenly attached to the surface of the lepidolite slag particles. This creates conditions for the rapid release and uniform distribution of ferrate ions after subsequent water addition. The low-speed mixing method can prevent the potassium ferrate powder from decomposing and becoming ineffective due to mechanical force, while also preventing excessive heating of the material and moisture evaporation from affecting the efficiency of subsequent oxidation reactions.

[0075] The specific implementation of step S04 is as follows: Calculate the total water addition based on the optimal moisture content determined in step S02. Divide the total water addition into three equal parts and add the water to the mixture prepared in step S03 using a phased water addition method. After the first water addition, start the mixer and mix for 2-3 minutes to allow the water to initially penetrate into the surface of the lithium mica residue particles. After the second water addition, stir again for 2-3 minutes to promote the diffusion of water into the interior of the lithium mica residue particles. After the third water addition and stirring, transfer the mixture to a sealed container for simmering. The simmering container is covered with a polyethylene film to prevent moisture evaporation. The simmering time is controlled within the range of 5-8 hours. During the simmering process, manually turn the mixture every 1-2 hours to promote uniform moisture distribution. The purpose of this step is to achieve sufficient water penetration into the lithium mica residue particles through phased water addition and simmering treatment, allowing heavy metal ions in the lithium mica residue to be absorbed into the surface of the particles. and The mixture is fully dissolved and undergoes an oxidation reaction with ferrate ions. The method of adding water in stages can avoid the clumping of the mixture and uneven moisture distribution caused by adding too much water at once. The curing process provides sufficient reaction time for the oxidation reaction, so that the oxidation and solidification effect of heavy metal ions can reach the optimal state.

[0076] The specific implementation of step S05 is as follows: After the simmering process is completed, the actual moisture content of the lithium mica residue wet material is determined by drying method. At the same time, the surface temperature of the mixture is measured by infrared thermometer and the internal temperature of the mixture is measured by insertion temperature probe. The average value of the temperature measurement values ​​at multiple points is taken as the temperature monitoring value. The ratio of the actual moisture content to the optimum moisture content is calculated. When the ratio is less than 0.85, the atomizing spray system is started to replenish water. The atomizing spray uses atomizing nozzles with an aperture of 0.3-0.5mm, the spray pressure is set to 0.2-0.4MPa, and the spray time for a single spray is controlled at 30-60s. After spraying, the mixture is left to stand for 5-10 minutes to allow the water to penetrate. Then the moisture content is measured again to determine whether further water replenishment is needed. When the temperature monitoring value exceeds 55℃, the subsequent water replenishment operation is changed to use cooling water with a temperature of 5-15℃ instead of room temperature water. The purpose of this step is to ensure that the moisture content and temperature of the mixture are within a suitable range through real-time monitoring and dynamic adjustment. The atomized spray water replenishment method can evenly disperse the water in the form of fine droplets on the surface of the mixture, avoiding the clumping problem caused by local over-wetting. The cooling water pre-cooling treatment controls the rate of temperature rise of the mixture by absorbing the heat released by the lime hydration reaction, preventing the rapid evaporation of water and the decomposition and failure of potassium ferrate caused by high temperature.

[0077] The specific implementation of step S06 is as follows: Lime and composite modified adsorbent material are weighed according to the specified ratio. These two materials are then added to the wet lithium mica slag treated in step S05 using an intermittent stirring method. Temperature control is achieved by setting alternating stirring and stopping cycles. First, an intermittent stirring parameter calibration experiment is conducted. Five initial intermittent stirring stop times are set: 0.5 min, 1 min, 1.5 min, 2 min, and 2.5 min. Five initial stirring times are set: 1 min, 1.5 min, 2 min, 2.5 min, and 3 min. Stirring experiments are conducted for 25 parameter combinations. During stirring, multi-point temperature sensors are used to monitor the mixture temperature in real time, recording the temperature peak, which is the highest temperature value observed during stirring. At the end of stirring, the temperature at each monitoring point is measured, and the standard deviation is calculated. The reciprocal of the standard deviation is used as the temperature uniformity index, starting from 25... From the experimental data, the experimental group with the lowest temperature peak and the highest temperature uniformity was selected. The parameters corresponding to this experimental group are the optimal initial intermittent stirring pause time and the optimal initial stirring time. The intermittent stirring pause time adjustment coefficient is obtained by dividing the optimal initial intermittent stirring pause time by 1 min, and the stirring time adjustment coefficient is obtained by dividing the optimal initial stirring time by 2 min. Then, the actual parameters are calculated according to the intermittent stirring parameter calculation function. The input of the calculation function includes the temperature monitoring value of the lithium mica slag wet material, the actual moisture content, the intermittent stirring pause time adjustment coefficient, and the stirring time adjustment coefficient. The output is the actual intermittent stirring pause time and the actual stirring time. The calculation principle is to dynamically adjust the parameters based on the ratio of the temperature monitoring value to the reference temperature of 25℃ and the ratio of the actual moisture content to the optimum moisture content. When the temperature rises, the pause time is automatically extended to increase heat dissipation; when the moisture content decreases, the stirring time is automatically shortened to reduce moisture evaporation. The purpose of this step is to effectively control the temperature rise effect caused by the lime hydration reaction while ensuring the mixing uniformity through intermittent stirring. The calibration experiment provides a quantitative experimental basis for parameter adjustment, and the parameter calculation function realizes intelligent dynamic adjustment of stirring parameters based on real-time monitoring data.

[0078] The specific implementation of step S07 is as follows: Blast furnace slag powder is weighed according to the specified ratio, and the slag powder is mixed with water at a mass ratio of 1:10 to 1:13. A slag powder suspension is prepared by stirring with a high-speed disperser for 3 to 5 minutes to ensure that the slag powder particles are uniformly dispersed in the water to form a stable suspension system. Then, a batch feeding optimization scheduling strategy is adopted to determine the addition scheme of the suspension. First, the surface of the mixture is divided into 5 to 10 feeding location nodes. Temperature sensors and moisture content sensors are placed at each node for real-time monitoring. The feeding process is modeled as a traveling salesman problem, starting from the initial feeding point and sequentially visiting all feeding points. The optimization objective is to minimize the total path length from the initial feeding point to the current feeding point. The constraint is that each feeding point node is visited only once. The optimal feeding sequence is obtained by solving this Traveling Salesman Problem. After determining the feeding sequence, the amount of each batch of feed is dynamically allocated based on the temperature and moisture content monitoring values ​​of each feeding point node. Nodes with higher temperatures are allocated smaller amounts to avoid exacerbating the exothermic volcanic ash reaction, while nodes with lower moisture content are allocated larger amounts to compensate for moisture loss. The slag powder suspension is added to the mixture in batches according to the optimized sequence and allocation, with local mixing for 1–2 minutes after each batch. The purpose of this step is to achieve uniform distribution of slag powder in the mixture through batch feeding and path optimization. The application of the Traveling Salesman Problem model minimizes the movement distance during feeding and improves feeding efficiency. The dynamic allocation strategy is adjusted according to the temperature and moisture content differences at each location, avoiding uneven volcanic ash reaction and local overheating caused by local enrichment of slag powder.

[0079] The specific implementation of step S08 is as follows: After all materials are mixed, the temperature rise rate and water loss rate of the mixture are measured by a real-time monitoring system. The temperature rise rate is obtained by calculating the temperature increase per unit time, and the water loss rate is obtained by calculating the percentage decrease in moisture content per unit time. Then, a hydration reaction control game model is established for two-layer optimization. This game model includes an upper-layer model and a lower-layer model. The upper-layer model aims to maximize temperature uniformity. The input parameters include the temperature monitoring values ​​at each monitoring point, the intermittent stirring pause time, and the heat dissipation coefficient. The output is the optimized intermittent stirring pause time. Its objective function comprehensively considers the ratio of the temperature standard deviation to the reference value of 10℃, the ratio of the intermittent stirring pause time to the reference value of 1min, and the influence of moisture content deviation. Multi-objective collaborative optimization is achieved through exponential functions and coupling terms. The constraints require that the intermittent stirring pause time be within the range of 1 to 3min and that the difference between the maximum and minimum temperatures at each monitoring point not exceed 15℃. The lower-layer model aims to maximize moisture content stability. The input parameters include the actual temperature rise rate of the mixture, the temperature rise rate, and the water loss rate. The objective function takes into account the actual moisture content, the frequency of atomized spray water replenishment, and the evaporation rate coefficient, and outputs the optimized atomized spray water replenishment frequency. It comprehensively considers the ratio of the absolute value of the difference between the actual and optimum moisture content to the reference value of 2%, the ratio of the atomized spray water replenishment frequency to the reference value of 6 times / h, and the influence of the temperature standard deviation. The constraints require the atomized spray water replenishment frequency to be in the range of 3–12 times / h and the ratio of the actual to optimum moisture content to be in the range of 0.85–1.15. The upper and lower level models influence each other through coupling coefficients. The process involves iterative solutions. The upper-level model's moisture content deviation coupling term is set to 0.3–0.5 times the optimal moisture content deviation reference value, while the lower-level model's temperature standard deviation coupling term is set to 0.2–0.4 times the temperature standard deviation reference value. When the temperature rise rate exceeds 8℃ / min, the intermittent stirring pause time is increased to 2 minutes based on the upper-level model's optimization results to enhance heat dissipation. When the water loss rate exceeds 0.5% / min, the frequency of atomized spraying is increased based on the lower-level model's optimization results to maintain stable moisture content. The purpose of this step is to achieve intelligent collaborative optimization of temperature and moisture control through a game theory model. The upper-level model focuses on achieving uniform temperature distribution, while the lower-level model focuses on maintaining stable moisture content. The two models mutually constrain and collaborate through coupling terms, seeking the optimal balance between temperature and moisture control to ensure that the hydration reaction process of the modified lithium mica slag roadbed filler is under control.

[0080] It should be noted that the key technical concepts of this invention include the following three aspects. First, there is the intermittent stirring temperature control technology. This technology achieves thorough mixing of materials during the stirring phase and utilizes natural heat dissipation to reduce the internal temperature of the mixture during the pause phase, avoiding the temperature accumulation effect caused by traditional continuous stirring. The parameter calculation function established through calibration experiments can dynamically adjust the stirring parameters based on real-time monitored temperature and moisture content data, achieving precise and intelligent temperature control. Compared to traditional fixed-parameter stirring methods, this technology can effectively suppress the temperature rise caused by lime hydration and volcanic ash reactions while ensuring mixing uniformity, preventing rapid evaporation of moisture and decomposition of potassium ferrate due to high temperatures, significantly improving the efficiency of heavy metal oxidation and solidification and the long-term stability of roadbed filler. Secondly, there is the batch feeding optimization scheduling technology based on the Traveling Salesman Problem (TSP). This technology models the feeding process of slag powder suspension as a TSP, optimizes the feeding sequence by solving for the shortest path, and dynamically allocates the feeding amount according to the temperature and moisture content differences at each feeding location. Compared with traditional one-time feeding or uniform batch feeding methods, this technology achieves spatial optimization of slag powder distribution in the mixture, ensuring the uniformity of the pozzolanic reaction while avoiding local overheating and uneven moisture distribution, effectively improving the overall performance uniformity of the subgrade filler. Thirdly, there is the hydration reaction control technology driven by a two-layer game model. This technology establishes an upper-level model with the goal of maximizing temperature uniformity and a lower-level model with the goal of maximizing moisture content stability. The two models influence each other and optimize synergistically through coupling terms. Compared with traditional single-objective control methods, this technology achieves synergistic optimization of temperature control and moisture control, maintaining stable moisture content while ensuring uniform temperature distribution, avoiding the problem of neglecting one aspect for another caused by a single control strategy, and significantly improving the controllability of the hydration reaction process and the stability of the subgrade filler performance. The synergistic effect of these three technical approaches lies in the fact that intermittent stirring technology provides a basic means for temperature control, batch feeding optimization technology realizes the optimization of material spatial distribution, and the two-layer game model coordinates the two key control variables of temperature and moisture at a higher level. The three work together to form a complete technical system from micro-reaction control to macro-process optimization. Compared with the traditional experience-driven preparation method, this synergistic technical system realizes the precision, intelligence and controllability of the preparation process of modified lithium mica slag roadbed filler, fundamentally improving the heavy metal solidification efficiency, mechanical property stability and long-term durability of the product.

[0081] It should be noted that this invention also solves the following technical problems: In the preparation process of lithium mica slag roadbed filler, the chemical properties of various harmful components such as manganese ions, thallium ions, beryllium ions and fluoride ions contained in lithium mica slag are quite different. Traditional single solidification agent treatment methods are difficult to achieve efficient solidification of harmful ions with different properties. Manganese ions and thallium ions need to be converted into high-valence precipitates through oxidation reactions, while beryllium ions and fluoride ions need to be fixed through co-precipitation reactions and adsorption coordination. Simply relying on the alkaline precipitation effect of lime or the physical encapsulation effect of slag powder cannot simultaneously meet the solidification requirements of multiple harmful ions, resulting in some harmful ions being insufficiently solidified and re-dissolving during later use. This invention constructs a multi-component synergistic solidification system consisting of potassium ferrate oxidation, lime co-precipitation, composite adsorbent material coordination adsorption, and blast furnace slag powder volcanic ash cementation. The system utilizes the strong oxidizing properties of potassium ferrate to oxidize manganese and thallium ions into insoluble manganese dioxide and thallium hydroxide precipitates. Hydroxide ions generated by lime hydration form co-precipitates with beryllium ions and oxidation products. Hydroxyl groups on the surface of the composite modified adsorbent material form coordination bonds with fluoride ions and undergo isomorphous substitution with beryllium ions. A dense cementing layer is generated by the volcanic ash reaction of blast furnace slag powder to encapsulate the formed precipitates. Through the sequential synergistic effect of multiple solidification mechanisms, efficient solidification of harmful ions with different chemical properties is achieved.

[0082] In addition, the present invention also solves the technical problem that uneven distribution of curing material in the mixture leads to large differences in curing effect in local areas. The traditional one-time centralized feeding method causes lime and slag powder to accumulate on the surface of the mixture. Although continuous stirring can promote material diffusion, it can also cause the concentration of curing material in local areas to be too high while the concentration in other areas is insufficient. The hydration reaction and volcanic ash reaction in the high concentration area are too violent, resulting in local overheating. The curing reaction in the low concentration area is insufficient, resulting in the residue of harmful ions. This invention employs an intermittent stirring method to separately add lime and composite modified adsorbent materials. During the pause phase, the materials naturally diffuse and penetrate into the mixture under the influence of gravity and concentration gradient. After preparing the blast furnace slag powder into a suspension, the feeding path is optimized based on the traveling salesman problem model. This allows the slag powder suspension to sequentially visit each feeding point node on the surface of the mixture along the shortest path. Simultaneously, the batch addition amount is dynamically adjusted based on the temperature and moisture content monitoring values ​​of each feeding point node. The addition amount is reduced at high-temperature locations to avoid excessively vigorous volcanic ash reaction, while the addition amount is increased at low-moisture-content locations to replenish moisture and promote hydration reaction. This achieves uniform distribution of the solidified material and spatial consistency of the solidification reaction, ensuring the uniformity of the overall solidification effect of the lithium mica slag roadbed filler.

[0083] Specifically, the principle of this invention is as follows: The technical principle of this invention lies in achieving a dynamic balance between temperature and moisture through the cyclical operation of intermittent stirring and the coordinated control of a two-layer game optimization model. The intermittent stirring method decomposes the continuous stirring process into a cyclical operation of alternating stirring and pauses. During the stirring phase, the mechanical action ensures the solidified material is uniformly dispersed in the lithium mica slag, promoting the full progress of hydration and volcanic ash reactions. During the pause phase, mechanical stirring ceases, eliminating the generation of mechanical heat. The mixture dissipates heat to the environment through surface convection and internal heat conduction, gradually reducing the temperature to a suitable range. The intermittent stirring parameter calculation function uses the ratio of the monitored temperature value to the reference temperature value and the ratio of the moisture content to the optimum moisture content to achieve real-time adjustment of the pause and stirring times. At high temperatures, extending the pause time increases heat dissipation; at low moisture content, shortening the stirring time reduces evaporation loss. The upper-level model of the hydration reaction control game model optimizes the intermittent stirring pause time with the goal of minimizing the temperature standard deviation, while the lower-level model optimizes the frequency of atomized spray water replenishment with the goal of minimizing the moisture content deviation. The two models are linked by coupling terms to link temperature control and moisture control, and seek the global optimal solution under the premise of satisfying their respective constraints. This ensures that the hydration reaction and the volcanic ash reaction always take place under suitable temperature and sufficient moisture conditions, thereby ensuring the full generation and stable existence of cementitious products and improving the solidification effect of lithium mica slag roadbed filler.

[0084] The following provides a specific embodiment 1 of the second aspect of the present invention, and the specific implementation of each step in this embodiment 1 is described in detail below.

[0085] In this embodiment, the specific implementation of step S01 is the same as described above, and will not be repeated in detail here.

[0086] The specific implementation of step S02 is as follows: In accordance with the compaction test method in the Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering, a heavy compactor is used to conduct a compaction test on the modified lithium mica slag roadbed dry mix. During the test, 5 to 7 different moisture content gradients are set, and 3 parallel samples are prepared for each moisture content gradient. By measuring the dry density values ​​of the samples at different moisture contents, a curve of the relationship between dry density and moisture content is plotted, and the maximum dry density and optimum moisture content value corresponding to the peak value of the curve are determined. At the same time, during the compaction test, multi-point temperature sensors are used to monitor the temperature of the mixture in real time, and the temperature change data from the start of water addition to the completion of compaction are recorded to establish a temperature change curve over time.

[0087] The specific implementation methods for steps S03-S05 are the same as those described above, and will not be repeated in detail here.

[0088] The specific implementation of step S06 is as follows: Lime and composite modified adsorbent material are weighed according to the specified ratio. These two materials are then added to the wet lithium mica slag treated in step S05 using an intermittent stirring method. Temperature control is achieved by setting alternating stirring and stopping cycles. First, an intermittent stirring parameter calibration experiment is conducted. Five initial intermittent stirring stop times are set: 0.5 min, 1 min, 1.5 min, 2 min, and 2.5 min. Five initial stirring times are set: 1 min, 1.5 min, 2 min, 2.5 min, and 3 min. Stirring experiments are conducted for each of the 25 parameter combinations. During the stirring process, a multi-point temperature sensor is used to monitor the temperature of the mixture in real time, recording the temperature peak, which is the highest temperature value observed during stirring. At the end of stirring, the temperature at each monitoring point is measured, and the standard deviation is calculated. The formula for calculating temperature uniformity is as follows:

[0089] ;

[0090] In the formula, Temperature uniformity, unit: ; The standard deviation of the temperature at each monitoring point at the end of stirring is expressed in °C. From 25 sets of experimental data, the experimental group with the lowest temperature peak and the highest temperature uniformity was selected. The parameters corresponding to this experimental group are the optimal initial intermittent stirring pause time and the optimal initial stirring time. The formulas for calculating the intermittent stirring pause time adjustment coefficient and the stirring time adjustment coefficient are as follows:

[0091] ;

[0092] ;

[0093] In the formula, This is a dimensionless adjustment coefficient for the intermittent stirring pause time. The optimal initial intermittent stirring pause time, in minutes; The baseline intermittent stirring pause time is set to 1 minute. This is a dimensionless coefficient for adjusting the stirring time. The optimal initial stirring time is given in minutes. The baseline stirring time is 2 minutes. After obtaining the adjustment coefficient from the calibration experiment, the actual operating parameters are calculated using the intermittent stirring parameter calculation function, which is described below:

[0094] ;

[0095] ;

[0096] In the formula, This refers to the actual intermittent stirring pause time, in minutes. The temperature monitoring value of wet lithium mica residue is in °C. This is a temperature reference value, taken as 25℃. The actual moisture content of the wet lithium mica residue is expressed in % (%). The optimal moisture content is expressed in % (%). This represents the actual mixing time, in minutes. The intermittent mixing parameter calculation function achieves dynamic parameter optimization through cross-adjustment of the temperature ratio and moisture content ratio. When the monitored temperature value increases, the temperature ratio... Enlargement leads to Extend the time to increase heat dissipation, while the moisture content ratio Located in the denominator, making By shortening the time to reduce water evaporation, this function implements a coordinated regulation mechanism for temperature and moisture control.

[0097] The specific implementation of step S07 is as follows: Blast furnace slag powder is weighed according to the specified ratio, and the slag powder is mixed with water at a mass ratio of 1:10 to 1:13. A slag powder suspension is prepared by stirring with a high-speed disperser for 3 to 5 minutes. Then, a batch feeding optimization scheduling strategy is used to determine the addition scheme of the suspension. First, the surface of the mixture is divided into... Each feeding location node The integers are between 5 and 10. Temperature and moisture sensors are placed at each node. The feeding process is modeled as a traveling salesman problem for path optimization. The objective function of the traveling salesman problem is expressed as follows:

[0098] ;

[0099] In the formula, This represents the total path length, in meters (m). This represents the total number of feeding locations, dimensionless. For nodes To the node The distance, in meters; As a decision variable, when the feeding path starts from node Directly reach the node hour ,otherwise The traveler's sales problem is dimensionless. The constraints are stated as follows:

[0100] ;

[0101] ;

[0102] ;

[0103] In the formula, the first constraint condition represents each node There is only one outgoing edge, and the second constraint condition represents each node. There is only one incoming edge, and the third constraint is the sub-loop elimination constraint, where For any non-empty proper subset of the node set, For subset The number of nodes in the loop is constrained to ensure that there are no subloops that do not contain the initial node. After solving the Traveling Salesman Problem to obtain the optimal feeding sequence, the amount of each batch of feed is dynamically allocated based on the temperature and moisture content monitoring values ​​of each feeding location node. The formula for calculating the amount of each batch of feed is as follows:

[0104] ;

[0105] ;

[0106] ;

[0107] In the formula, For nodes The amount added is expressed in kg; The total amount of slag powder suspension is expressed in kg. For nodes The temperature weighting coefficient is dimensionless. For nodes The moisture content weighting coefficient is dimensionless. For nodes Temperature monitoring values, in °C; and These are the maximum and minimum temperature monitoring values ​​for all nodes, respectively, in °C. For nodes The moisture content monitoring value, in % %. and These represent the maximum and minimum values ​​of moisture content monitoring at all nodes, in percentage. The temperature weighting coefficient calculation formula uses the maximum value minus the measured value to give nodes with higher temperatures a smaller weighting coefficient, while the moisture content weighting coefficient calculation formula uses the optimal value minus the measured value to give nodes with lower moisture content a larger weighting coefficient. Dynamic optimization of the amount added to each node is achieved through the normalization of the weighting coefficient allocation.

[0108] The specific implementation of step S08 is as follows: after all materials are mixed, the temperature rise rate and water loss rate of the mixture are measured by a real-time monitoring system. The calculation formulas for the temperature rise rate and water loss rate are expressed as follows:

[0109] ;

[0110] ;

[0111] In the formula, This is the rate of temperature rise, expressed in °C / min. and They are time points and Temperature monitoring values, in °C; and These represent two consecutive monitoring time points, in minutes. This represents the rate of water loss, expressed as % / min. and They are time points and The moisture content is monitored and expressed as a percentage. When the temperature rise rate exceeds 8℃ / min or the water loss rate exceeds 0.5% / min, a two-layer optimization game model for hydration reaction control is established. This game model consists of an upper-layer model and a lower-layer model. The upper-layer model aims to maximize temperature uniformity, and its objective function is expressed as follows:

[0112] ;

[0113] In the formula, The objective function value of the upper-level model is dimensionless. This represents the standard deviation of the temperature monitoring values ​​at each monitoring point, in °C. This is a reference value for the standard deviation of temperature, and its value is 10℃. This refers to the intermittent stirring pause time, expressed in minutes. The coupling coefficient is 0.3 to 0.5 and is dimensionless. Moisture content deviation, in percentage (%) The moisture content deviation is a reference value and is set to 1%. The constraints of the upper-level model are as follows:

[0114] ;

[0115] ;

[0116] In the formula, The unit is min; and These represent the maximum and minimum temperature readings at each monitoring point, in °C. The lower-level model optimizes for maximizing moisture content stability, and its objective function is expressed as follows:

[0117] ;

[0118] In the formula, This represents the objective function value of the lower-level model, which is dimensionless. The absolute value of the difference between the actual moisture content and the optimum moisture content of the mixture, expressed in % (%). This is a reference value for the moisture content difference, and the value is taken as 2%. This refers to the frequency of water replenishment for atomized spraying, expressed in times per hour. The reference value for the frequency of water replenishment for atomized spraying is 6 times / hour; The coupling coefficient is 0.2 to 0.4 and is dimensionless. The constraints of the lower-level model are stated as follows:

[0119] ;

[0120] ;

[0121] In the formula, The unit is times / hour. The formula for calculating moisture content deviation is as follows:

[0122] ;

[0123] ;

[0124] In the formula, For monitoring points Actual moisture content, in % . The value represents the average actual moisture content at all monitoring points, expressed as a percentage. The upper and lower models influence each other through coupling terms. The moisture content deviation coupling term in the objective function of the upper model requires temperature optimization to consider the uniformity of moisture distribution, while the temperature standard deviation coupling term in the objective function of the lower model requires moisture optimization to consider the uniformity of temperature distribution. The two models achieve collaborative optimization through iterative solutions. When the temperature rise rate exceeds a threshold, the intermittent stirring pause time is increased to 2 minutes based on the optimization results of the upper model. When the water loss rate exceeds a threshold, the frequency of atomized spray water replenishment is increased based on the optimization results of the lower model.

[0125] To better understand and implement this invention, several specific embodiments are provided below. It should be noted that the methods described in the following embodiments are conventional methods, and the raw materials, reagents, and equipment, unless otherwise specified, are commercially available. For ease of description of the formulation of the first aspect of this invention, the preparation methods in this set of embodiments and their comparative examples are described using simplified methods. The parameters related to the raw materials used in the following embodiments include:

[0126] 1) Potassium ferrate powder: effective K2FeO4 content 91.4%, particle size range between 75 and 150 μm;

[0127] 2) Lime: The effective calcium oxide and magnesium oxide content is 78%, and the passing rate of 0.08mm fineness is 85%;

[0128] 3) Composite modified adsorbent material: specific surface area is 202 m² / kg;

[0129] 4) Blast furnace slag powder: S95 grade blast furnace slag powder;

[0130] 5) Water: pH = 6.5~7.8

[0131] The following is a detailed description of Example 1.

[0132] 1. A modified lithium mica slag roadbed filler, comprising solid components prepared in the following mass parts: 74 parts lithium mica slag, 1.2 parts potassium ferrate powder, 2 parts lime, 1.2 parts iron hydroxyl oxide, 0.6 parts aluminum hydroxyl oxide, 3 parts blast furnace slag powder, and 18 parts water.

[0133] 2. Lithium mica residue: The chemical composition includes the following percentages by mass: 25.2% SiO2, 20.3% Al2O3, 8.9% CaO, and 10.5% SO3; the particle size does not exceed 5 mm, the non-uniformity coefficient is 8.73, and the curvature coefficient should be 1.68; the total beryllium concentration in the leaching solution of lithium mica residue is 0.018 mg / L, the total thallium concentration is 0.011 mg / L, the total manganese concentration is 12.86 mg / L, and the fluoride concentration is 29.8 mg / L.

[0134] 3. The preparation method of the above-mentioned modified lithium mica slag roadbed filler is as follows:

[0135] S1. Weigh the lithium mica slag as described in claim 1, and mix it with potassium ferrate powder, lime, composite modified adsorbent material, and blast furnace slag powder to obtain modified lithium mica slag roadbed mixture.

[0136] S2. The maximum dry density of the modified lithium mica slag mixture was found to be 1.56 g / cm³ based on the compaction test. 3 The optimal moisture content is 18%.

[0137] S3. Weigh out the potassium ferrate powder according to claim 1 in proportion, add it to the lithium mica residue according to claim 1 and stir evenly;

[0138] S4. Weigh water according to the optimal moisture content ratio, spread it on the mixture obtained in step S3, stir evenly, and let it sit for 5-8 hours to obtain lepidolite slag wet material.

[0139] S5. Weigh the lime and composite modified adsorbent material according to the proportion described in claim 1, and add them to the wet lithium mica slag obtained in step S4, and stir evenly;

[0140] S6. Weigh out the blast furnace slag powder of claim 1 according to the proportion, dissolve it in a small amount of water, and spread it while stirring in the mixture obtained in step S5. After all materials are mixed evenly, the modified lithium mica slag roadbed filler can be obtained.

[0141] The following is a detailed description of Example 2.

[0142] 1. A modified lithium mica slag roadbed filler, comprising solid components prepared in the following mass parts: 76 parts lithium mica slag, 1.0 part potassium ferrate powder, 2.0 parts lime, 0.8 parts ferric hydroxide, 0.4 parts alumina hydroxide, 2.0 parts blast furnace slag powder, and 17.8 parts water.

[0143] 2. Lithium mica residue: The chemical composition includes the following percentages by mass: 32.2% SiO2, 18.1% Al2O3, 15.22% CaO, and 13.7% SO3; the particle size does not exceed 5 mm, the non-uniformity coefficient is 11.22, and the curvature coefficient should be 1.16; the total beryllium concentration in the leaching solution of lithium mica residue is 0.008 mg / L, the total thallium concentration is 0.004 mg / L, the total manganese concentration is 8.23 ​​mg / L, and the fluoride concentration is 14.8 mg / L.

[0144] 3. The preparation method of the above-mentioned modified lithium mica slag roadbed filler is as follows:

[0145] S1. Weigh out the lithium mica slag, mix it with potassium ferrate powder, lime, composite modified adsorbent material and blast furnace slag powder to obtain modified lithium mica slag mixture;

[0146] S2. The maximum dry density of the modified lithium mica slag roadbed mixture was found to be 1.47 g / cm³ based on compaction tests. 3 The optimal moisture content is 17.8%;

[0147] S3. Weigh out the potassium ferrate powder according to claim 1 in proportion, add it to the lithium mica residue according to claim 1 and stir evenly;

[0148] S4. Weigh water according to the optimal moisture content ratio, spread it on the mixture obtained in step S3, stir evenly, and let it sit for 5-8 hours to obtain lepidolite slag wet material.

[0149] S5. Weigh the lime and composite modified adsorbent material according to the proportion described in claim 1, and add them to the wet lithium mica slag obtained in step S4, and stir evenly;

[0150] S6. Weigh out the blast furnace slag powder of claim 1 according to the proportion, dissolve it in a small amount of water, and spread it while stirring in the mixture obtained in step S5. After all materials are mixed evenly, the modified lithium mica slag roadbed filler can be obtained.

[0151] The following is a detailed description of Example 3.

[0152] 1. A modified lithium mica slag roadbed filler, comprising solid components prepared in the following mass parts: 78 parts lithium mica slag, 0.8 parts potassium ferrate powder, 1.5 parts lime, 1.0 part iron hydroxyl oxide, 0.5 parts aluminum hydroxyl oxide, 2.2 parts blast furnace slag powder, and 16 parts water.

[0153] 2. Lithium mica residue: The chemical composition includes the following percentages by mass: 38.3.2% SiO2, 19.6% Al2O3, 21.8% CaO, and 13.8% SO3; the particle size does not exceed 5 mm, the non-uniformity coefficient is 9.19, and the curvature coefficient should be 1.09; the total beryllium concentration in the leaching solution of lithium mica residue is 0.003 mg / L, the total thallium concentration is 0.004 mg / L, the total manganese concentration is 3.83 mg / L, and the fluoride concentration is 18.27 mg / L.

[0154] 3. The preparation method of the above-mentioned modified lithium mica slag roadbed filler is as follows:

[0155] S1. Weigh out the lithium mica slag, mix it with potassium ferrate powder, lime, composite modified adsorbent material and blast furnace slag powder to obtain modified lithium mica slag mixture;

[0156] S2. Based on the compaction test, the maximum dry density of the modified lithium mica slag roadbed mixture was 1.58 g / cm3, and the optimum moisture content was 16%.

[0157] S3. Weigh out the potassium ferrate powder according to claim 1 in proportion, add it to the lithium mica residue according to claim 1 and stir evenly;

[0158] S4. Weigh water according to the optimal moisture content ratio, spread it on the mixture obtained in step S3, stir evenly, and let it sit for 5-8 hours to obtain lepidolite slag wet material.

[0159] S5. Weigh the lime and composite modified adsorbent material according to the proportion described in claim 1, and add them to the wet lithium mica slag obtained in step S4, and stir evenly;

[0160] S6. Weigh out the blast furnace slag powder of claim 1 according to the proportion, dissolve it in a small amount of water, and spread it while stirring in the mixture obtained in step S5. After all materials are mixed evenly, the modified lithium mica slag roadbed filler can be obtained.

[0161] The following is a detailed description of Example 4.

[0162] 1. A modified lithium mica slag roadbed filler, comprising solid components prepared in the following mass parts: 80 parts lithium mica slag, 0.8 parts potassium ferrate powder, 1.5 parts lime, 0.8 parts iron hydroxyl oxide, 0.4 parts aluminum hydroxyl oxide, 1.5 parts blast furnace slag powder, and 15 parts water.

[0163] 2. Lithium mica residue: The chemical composition includes the following percentages by mass: 35.6% SiO2, 21.5% Al2O3, 20.7% CaO, and 9.2% SO3; the particle size does not exceed 5 mm, the non-uniformity coefficient is 6.73, and the curvature coefficient should be 1.05; the total beryllium concentration in the leaching solution of lithium mica residue is 0.002 mg / L, the total thallium concentration is 0.006 mg / L, the total manganese concentration is 1.52 mg / L, and the fluoride concentration is 10.73 mg / L.

[0164] 3. The preparation method of the above-mentioned modified lithium mica slag roadbed filler is as follows:

[0165] S1. Weigh out the lithium mica slag, mix it with potassium ferrate powder, lime, composite modified adsorbent material and blast furnace slag powder to obtain modified lithium mica slag mixture;

[0166] S2. According to the compaction test, the maximum dry density of the modified lithium mica slag roadbed mixture is 1.44 g / cm3 and the optimum moisture content is 15%.

[0167] S3. Weigh out the potassium ferrate powder according to claim 1 in proportion, add it to the lithium mica residue according to claim 1 and stir evenly;

[0168] S4. Weigh water according to the optimal moisture content ratio, spread it on the mixture obtained in step S3, stir evenly, and let it sit for 5-8 hours to obtain lepidolite slag wet material.

[0169] S5. Weigh the lime and composite modified adsorbent material according to the proportion described in claim 1, and add them to the wet lithium mica slag obtained in step S4, and stir evenly;

[0170] S6. Weigh out the blast furnace slag powder of claim 1 according to the proportion, dissolve it in a small amount of water, and spread it while stirring in the mixture obtained in step S5. After all materials are mixed evenly, the modified lithium mica slag roadbed filler can be obtained.

[0171] The following is a detailed description of proportion 1.

[0172] The lithium mica slag roadbed filler used in this comparative example is the same as that in Example 1, except that potassium ferrate powder, lime, composite modified adsorbent material and blast furnace slag powder were not added, that is, an equal amount of lithium mica slag was used to replace the above materials.

[0173] For the modified lithium mica slag roadbed fillers obtained in Examples 2-5 and the lithium mica slag roadbed filler in Comparative Example 2, load-bearing ratio tests were conducted on the fillers obtained in each example and comparative example according to the "Specifications for Testing Geotechnical Engineering for Highways" (JTG 3430-2020). The test results are shown in Table 1. Meanwhile, according to the "Specifications for Testing Inorganic Binder Stabilized Materials for Highway Engineering" (JTG3441-2024), specimens of each group of fillers were formed. Then, each group of specimens was manually crushed into particles smaller than 3 mm. Leachate was prepared according to the "Horizontal Oscillation Method for Leaching Toxicity of Solid Waste" (HJ 557-2010). The leaching content of characteristic pollutants in the leachate was determined by atomic absorption spectrophotometry and inductively coupled plasma mass spectrometry, respectively. The test results are shown in Table 3.

[0174] Table 2: CBR Strength Test Results of Lithium Mica Slag

[0175] Note: The above CBR control values ​​are the minimum CBR values ​​required for subgrade fill material according to the "Specifications for Design of Highway Subgrade" (JTG D30-2015).

[0176] Table 3: Test Results of Characteristic Pollutant Concentrations in Leachate

[0177] Note: The above target limits are the concentration limits of modified lithium slag leachate required by the Jiangxi Provincial Local Standard "Technical Specification for the Use of Lithium Slag in Highway Subgrade Engineering (Trial)" (DB36 / T 1968-2024).

[0178] The test results in Tables 1 and 2 show that the lithium mica slag material has high strength and a CBR value far exceeding the requirements for roadbed fillers. The modified lithium mica slag filler prepared by this modification method has a further improved CBR value and excellent engineering performance. The content of characteristic pollutants in the leachate of the modified lithium mica slag roadbed fillers prepared in Examples 2-5 all meet the requirements of the "Technical Specification for the Utilization of Lithium Slag in Highway Subgrade Engineering (Trial)" (DB36 / T 1968-2024), indicating that the modification effect of lithium mica slag is good. Comparing Comparative Example 1 and Example 2, when potassium ferrate powder, lime, composite modified adsorbent material and blast furnace slag powder were not added to the lithium mica slag, the concentration of various characteristic pollutants was still lower than that of the raw materials. This may be because the Al2O3, CaO and other substances in the lithium mica slag underwent stabilization and solidification reactions during the process of adding water and molding. However, the concentration of various characteristic pollutants in Comparative Example 1 still significantly exceeded the requirements of the "Technical Specification for the Use of Lithium Slag in Highway Subgrade Engineering (Trial)" (DB36 / T 1968-2024) and could not be used as subgrade filler.

[0179] This invention utilizes potassium ferrate powder, lime, composite modified adsorbent materials, and blast furnace slag powder to modify lepidolite slag, turning waste into treasure, consuming the resources of lepidolite slag industrial solid waste, reducing resource waste and environmental pollution risks, and lowering production costs.

[0180] To better understand the preparation method provided in the second aspect of this invention, a specific application scenario example 6 is provided below: A technical team faces the problem of resource utilization of lithium mica residue in a highway subgrade project in a certain region. The lithium mica residue stockpile in this region reaches 150,000 tons, which contains , , Lithium mica slag contains heavy metal ions and fluoride ions, which pose environmental pollution risks if directly stored. There is currently no precedent for solidification treatment of lithium mica slag; it is mainly used for storage, or in the manufacture of ceramics or base materials. The technical team decided to adopt the modified lithium mica slag roadbed filler preparation method of this invention to transform lithium mica slag into an engineering material that meets the technical requirements for roadbed fillers.

[0181] The technical team first conducted a compositional analysis on the lithium mica residue, measuring the content of lithium mica residue... The content is 32%. The content is 20%. The content is 15%. The content is 11%, the particle size is mainly distributed in the range of 0-5mm, the non-uniformity coefficient is 6.2, and the curvature coefficient is 1.8. According to the formula requirements, 77 parts of lepidolite slag, 1 part of potassium ferrate powder, 1.8 parts of lime, 1.5 parts of composite modified adsorbent material, and 2 parts of blast furnace slag powder were weighed and dry-mixed to obtain modified lepidolite slag roadbed dry mix. The potassium ferrate powder contains effective... The content is 92%, and the particle size ranges from 90 to 130 μm. The effective calcium oxide and magnesium oxide content in the lime is 80%, and the passing rate of 0.08 mm fineness is 88%. The composite modified adsorbent material is composed of hydroxyl iron-aluminum composite oxides, wherein the mass percentage of hydroxyl iron oxide is 1.0%, the mass percentage of hydroxyl aluminum oxide is 0.5%, and the specific surface area is... The blast furnace slag powder is grade S95.

[0182] The technical team conducted compaction tests on the modified lithium mica slag roadbed dry mix and determined the maximum dry density to be [value missing]. The optimal moisture content was 13.5%, and the temperature change curve of the mixture was recorded. For example... Figure 2 As shown, the temperature change curve reflects the temperature evolution within the mixture at different time points. One part of potassium ferrate powder was weighed and added to 77 parts of lepidolite slag for the first stirring, which lasted 4 minutes at a stirring speed of 40 r / min. The ferrate ions generated after the potassium ferrate powder dissolved in water affect the lepidolite slag... and To carry out an oxidation reaction, Oxidized to And generate Precipitation, Oxidized to And generate precipitation.

[0183] Based on an optimal moisture content of 13.5%, the required water volume is 10.4 parts. The technical team added the water to the mixture in three stages, with each addition being 3.47 parts, and stirred for 2.5 minutes after each addition. The value is 7.5, which meets the requirement range of 6.5 to 9. After all water is added, a steaming process is performed for 6 hours. During the steaming process, the water fully wets the lithium mica residue particles, and the lithium mica residue... and Upon full contact with ferrate ions and undergoing an oxidation reaction, the ferrate ions themselves are reduced to... It acts as a colloid and plays a flocculation role.

[0184] After the curing process, the actual moisture content of the lithium mica residue wet material was measured to be 11.2% at a temperature of 28℃. The ratio of the actual moisture content to the optimum moisture content was 0.83, falling within the range of [0, 0.85), necessitating atomized spraying for water replenishment. The technical team used an atomizing nozzle with a nozzle orifice diameter of 0.4mm, a spraying pressure of 0.3MPa, and a single spraying time of 45s to adjust the actual moisture content to 13.2%. Atomized spraying evenly dispersed the moisture onto the surface of the mixture in the form of fine droplets, avoiding the problem of excessive local moisture leading to agglomeration of the mixture.

[0185] 1.8 parts lime and 1.5 parts composite modified adsorbent were weighed out and added to the wet lithium mica slag using intermittent stirring. The technical team determined the adjustment coefficients for intermittent stirring pause time and stirring time through intermittent stirring parameter calibration experiments. As shown in Table 4, the calibration experiment results show the influence of different initial parameter combinations on the temperature control effect of the mixture.

[0186] Table 4 Results of intermittent stirring parameter calibration experiment

[0187] The optimal initial intermittent stirring pause time was determined to be 2.5 min from the experimental data, and the optimal initial stirring time was determined to be 2.0 min. The calculated adjustment coefficients for the intermittent stirring pause time and the stirring time were 2.5 and 1.0, respectively. Based on the intermittent stirring parameter calculation function, the monitored temperature of the wet lithium mica slag was 28℃, the actual moisture content was 13.2%, the temperature reference value was 25℃, and the optimal moisture content was 13.5%. The calculated actual intermittent stirring pause time was 2.77 min, and the actual stirring time was 1.95 min. The technical team operated according to the intermittent stirring cycle, stirring for 1.95 min followed by a 2.77 min pause, for a total stirring time of 9 min. Figure 3 As shown, the internal temperature distribution of the mixture during intermittent mixing exhibits periodic fluctuations, and the temperature accumulation effect is reduced through natural heat dissipation during the rest phase.

[0188] Calcium oxide in lime hydrates to form calcium hydroxide, and the hydroxide ions provided by calcium hydroxide react with those of the oxidized product. and A precipitation reaction occurs, producing and Precipitation, provided by calcium hydroxide Reacts with fluoride ions to produce Precipitation. The hydroxyl groups on the surface of the composite modified adsorbent material react with fluoride ions through ion exchange to form iron-fluorine and aluminum-fluorine coordination bonds, which then form hydroxyl groups within the octahedral lattice of the alumina. and An isomorphous substitution reaction occurs in ferric hydroxyoxide. Promote and The oxidation reaction results in the formation of iron-manganese complexes and iron-thallium complexes by the hydroxyl groups and the oxidation products.

[0189] Two parts of blast furnace slag powder were weighed and dissolved in 18 parts of water to prepare a slag powder suspension. The slag powder and water were mixed at a mass ratio of 1:9 and stirred for 4 minutes. The technical team divided the surface of the mixture into eight feeding locations, each corresponding to a temperature monitoring point and a moisture content monitoring point. A batch feeding optimization scheduling strategy was adopted, and optimization calculations were performed based on a traveling salesman problem model to determine the order of addition of the slag powder suspension and the amount added in each batch. Figure 4 As shown, the optimized feeding path minimizes the total length of the slag powder suspension distribution path on the surface of the mixture. Following the optimized scheduling results, the technical team added the slag powder suspension to the mixture in 8 batches, stirring for 1.5 minutes after each addition. Nodes with higher temperature monitoring values ​​were allocated 2.0 parts of the suspension, while nodes with lower moisture content monitoring values ​​were allocated 2.5 parts.

[0190] After all materials were mixed, the temperature rise rate of the mixture was measured to be 6.8℃ / min, and the water loss rate was 0.35% / min, both within the control range. The technical team established a two-layer optimization model to control the hydration reaction. The upper-layer model aimed to maximize temperature uniformity, while the lower-layer model aimed to maximize moisture content stability. The standard deviation of the temperature monitoring values ​​at each monitoring point was 5.2℃, and the absolute value of the difference between the actual moisture content and the optimum moisture content of the mixture was 0.8%. Figure 5 As shown, the optimization results of the hydration reaction control game model indicate that the intermittent stirring pause time and the atomized spray water replenishment frequency gradually converge to the optimal equilibrium point during the iteration process. Through two-layer optimization calculation, the optimized intermittent stirring pause time is 2.2 min, and the atomized spray water replenishment frequency is 7 times / h, finally yielding the modified lithium mica slag roadbed filler.

[0191] The vitreous active components in blast furnace slag powder undergo a hydration reaction with the aluminosilicates in lime and lepidolite slag, generating calcium silicate hydration gel and calcium aluminate hydration gel, forming a dense cemented layer. The technical team conducted performance tests on the prepared modified lepidolite slag roadbed filler, achieving an unconfined compressive strength of 0.85 MPa. The leaching concentration was reduced to 0.08 mg / L. The leaching concentration was reduced to 0.005 mg / L. The leaching concentration was reduced to 0.003 mg / L, and the fluoride ion leaching concentration was reduced to 0.9 mg / L. All indicators met the technical specifications for roadbed fillers.

[0192] The technological advancements of this invention compared to traditional lithium mica slag solidification methods are mainly reflected in the following aspects. Traditional methods use a single solidifying agent, resulting in a limited fixation mechanism for heavy metal and fluoride ions. The treatment effect is restricted by the direct reaction between the solidifying agent and pollutants, failing to form multiple fixation barriers. This invention constructs a four-tiered fixation system—oxidative fixation, precipitation fixation, adsorption fixation, and gelation fixation—through the oxidation of potassium ferrate powder, the precipitation of lime, the adsorption and coordination of composite modified adsorbent materials, and the pozzolanic cementitious effect of blast furnace slag powder. These different fixation mechanisms synergistically enhance each other. Traditional methods cannot effectively control temperature accumulation and moisture loss during stirring, leading to uneven hydration reaction rates and affecting the stability of the solidification effect. This invention achieves temperature control through intermittent stirring, alternating between stirring and stopping, replenishes moisture during evaporation through atomized spraying, and seeks the optimal balance between temperature and moisture control through a two-layer optimization of a hydration reaction control game model, thereby ensuring that the hydration reaction proceeds uniformly under suitable temperature and moisture content conditions. Traditional methods lack spatial optimization scheduling when adding slag powder, which can easily lead to local enrichment of slag powder and uneven reaction of pozzolanic material. This invention optimizes the spatial distribution path of slag powder suspension by using a batch feeding optimization scheduling strategy based on the traveling salesman problem model. This minimizes the feeding distance while ensuring uniform distribution of slag powder on the surface of the mixture, thereby improving the spatial uniformity of pozzolanic reaction and the consistency of gelation effect.

[0193] It should be noted that the variables involved in this invention are explained in detail in Table 5 below.

[0194] Table 5. Variable Explanation Table

[0195] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A modified lithium mica slag roadbed filler, characterized in that, It is composed of the following solid components in parts by mass: 74-80 parts of lithium mica slag, 0.8-1.2 parts of potassium ferrate powder, 1.5-2 parts of lime, 1.2-1.8 parts of composite modified adsorbent material, 1.5-3 parts of blast furnace slag powder, and 15-20 parts of water.

2. The modified lithium mica slag roadbed filler according to claim 1, characterized in that, The lithium methane slag comprises the following chemical composition with the following oxide percentages: 25-40%. 18-22% 8-22% 9-14% The particle size is concentrated in the range of 0 to 5 mm, the non-uniformity coefficient is not less than 5, and the curvature coefficient is in the range of 1 to 3.

3. The modified lithium mica slag roadbed filler according to claim 1, characterized in that, The potassium ferrate powder is effective The content is not less than 90%, the particle size range is between 75 and 150 μm, and the ferrate ions generated after potassium ferrate powder is dissolved in water have an effect on the lithium mica residue. and It undergoes an oxidation reaction.

4. The modified lithium mica slag roadbed filler according to claim 1, characterized in that, The lime contains no less than 78% effective calcium oxide and magnesium oxide, and has a fineness of 0.08 mm with a pass rate of more than 85%. The calcium oxide in the lime is hydrated to generate calcium hydroxide and provides hydroxide ions.

5. The modified lithium mica slag roadbed filler according to claim 1, characterized in that, The composite modified adsorbent material is composed of hydroxyl iron-aluminum composite oxides, with 0.8%–1.2% hydroxyl iron oxide and 0.4%–0.6% hydroxyl aluminum oxide by mass, and has a specific surface area of ​​not less than 200. .

6. A method for preparing modified lithium mica slag roadbed filler, characterized in that, The process includes the following steps: Weighing lithium mica slag, potassium ferrate powder, lime, composite modified adsorbent material, and blast furnace slag powder, and dry-mixing them to obtain modified lithium mica slag roadbed dry mix; conducting compaction tests on the modified lithium mica slag roadbed dry mix to determine the maximum dry density and optimum moisture content, and recording the temperature change curve of the mixture; weighing potassium ferrate powder according to the ratio and adding it to the lithium mica slag for the first stirring; adding water to the mixture in three stages according to the optimum moisture content ratio and performing a steaming treatment; after steaming, measuring the actual moisture content and temperature of the wet lithium mica slag material, and performing atomized spray water replenishment or cooling water pre-cooling treatment based on the measurement results. Lime and composite modified adsorbent were weighed according to proportion and added to the wet lithium mica slag material by intermittent stirring. The intermittent stirring pause time adjustment coefficient and stirring time adjustment coefficient were determined by the intermittent stirring parameter calibration experiment. The actual intermittent stirring pause time and actual stirring time were calculated according to the intermittent stirring parameter calculation function. Blast furnace slag powder was weighed according to proportion and dissolved in water to prepare slag powder suspension. The slag powder suspension was added to the mixture in batches by a batch feeding optimization scheduling strategy. After all materials were mixed, the temperature rise rate and water loss rate of the mixture were measured and a hydration reaction control game model was established for two-layer optimization.

7. The preparation method of the modified lithium mica slag roadbed filler according to claim 6, characterized in that, The water The value is 6.5-9, water A value below 6.5 negatively impacts the co-precipitation and stabilization / solidification reactions, affecting the water's... A value higher than 9 intensifies the decomposition reaction of potassium ferrate.

8. The preparation method of the modified lithium mica slag roadbed filler according to claim 7, characterized in that, The braising process allows moisture to fully penetrate the lithium mica residue particles, thus reducing the moisture content in the lithium mica residue. and It comes into full contact with ferrate ions and undergoes an oxidation reaction; the simmering time is 5–8 hours.

9. The preparation method of the modified lithium mica slag roadbed filler according to claim 8, characterized in that, The atomized spray water replenishment uses an atomizing nozzle with a nozzle orifice diameter of 0.3–0.5 mm and a spray pressure of 0.2–0.4 mm. The spraying time is 30-60 seconds. The atomized spraying water replenishment disperses the water evenly on the surface of the mixture in the form of fine droplets.

10. The method for preparing modified lithium mica slag roadbed filler according to claim 9, characterized in that, The cooling water precooling treatment uses cooling water with a temperature of 5-15℃ instead of room temperature water for subsequent water addition operations. The cooling water absorbs the heat released by the lime hydration reaction and the volcanic ash reaction, reducing the water evaporated due to the rise in temperature of the mixture.

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