Industrial solid waste harmless regeneration soil and preparation method thereof

Abstract

The present application relates to the technical field of industrial solid waste treatment, and discloses harmless regeneration soil of industrial solid waste and a preparation method thereof, which comprises the following steps: injecting a multi-dentate coordination passivation solution containing carboxyl and phosphate into activated powder, and reacting under temperature control and pH control; bridging and steric hindering of the ligand and the hydrogen bond of the hydroxyl group promote the formation of a cyclic chelate structure of heavy metal ions and active sites, and a primary passivated powder is obtained; dry mixing the primary passivated powder with biochar containing a condensed ring aromatic structure and an amphiphilic polymer, applying a directional vibration shear flow field, using electron cloud overlap, dipole polarization traction and residual van der Waals force vector superposition to induce particle directional self-assembly and dense arrangement, building a hierarchical porous three-dimensional skeleton, and obtaining a recombined precursor. The present application can reconstruct the particle topological network from the level of molecular interface force, and simultaneously control the pore mechanics and chemical stability.

Description

Technical Field

[0001] This invention relates to the field of industrial solid waste treatment technology, specifically to a method for preparing harmless recycled soil from industrial solid waste. Background Technology

[0002] Industrial processes such as metallurgical smelting, mining and beneficiation, and chemical production generate large amounts of industrial solid waste annually, including metallurgical slag, electrolytic manganese slag, and fly ash, which are rich in heavy metals and harmful components. Transforming this solid waste into recycled soil for ecological restoration projects through harmless treatment and structural reconstruction is a key technological approach to alleviate the pressure of solid waste accumulation and achieve matrix reconstruction and vegetation restoration in mining areas.

[0003] However, existing industrial solid waste regeneration soil processes mostly rely on single physical mixing ratios or the addition of broad-spectrum chemical passivating agents, lacking precise control over the coordination topology network, hydrogen bond cross-linking system, and van der Waals force synergistic mechanism between the active sites of silica-alumina hydroxyl groups on the surface of solid waste particles and heavy metal ions. This process deficiency leads to a severe deficiency in the interfacial binding energy of regenerated soil micro-aggregates, macroscopically manifested as rapid attenuation of shear strength under alternating wet and dry conditions, uncontrolled and disordered capillary pore connectivity. Under the stress coupling effects of complex environments such as acidic rainwater leaching, groundwater infiltration, or freeze-thaw cycles, heavy metal-ligand complex bonds are prone to hydrolysis, breakage, and ion exchange desorption, resulting in secondary heavy metal migration pollution and the disintegration of soil micro-aggregate structure. Existing technical solutions cannot simultaneously achieve long-term in-situ retention of heavy metals, hierarchical pore structure optimization, and improvement of macroscopic mechanical stability, failing to meet the stringent requirements for long-term service performance and harmlessness indicators of regenerated soil in ecological restoration projects such as steep slope treatment and abandoned mine backfilling. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing harmless recycled soil from industrial solid waste, which can reconstruct the particle topology network at the molecular interface force level and simultaneously regulate pore mechanics and chemical stability.

[0005] A method for preparing harmless recycled soil from industrial solid waste includes the following steps: Step 1: High-shear deagglomeration of industrial solid waste is performed to destroy the van der Waals force agglomeration structure between particles and expose the surface silicon-aluminum hydroxyl active sites to obtain activated powder. Step 2: Inject a multidentate coordination passivation solution containing carboxyl and phosphate groups into the activated powder, and react under controlled temperature and pH. Through hydrogen bonding bridging between the ligand and hydroxyl groups and steric hindrance, heavy metal ions are promoted to form a cyclic chelate structure with the active site to obtain primary passivation powder. Step 3: The primary passivated powder is dry-mixed with biochar containing a fused ring aromatic structure and an amphiphilic polymer. A directional vibration shear flow field is applied, and the particles are oriented to self-assemble and densely arranged by utilizing electron cloud overlap, dipole polarization traction and residual van der Waals force vector superposition to construct a hierarchical porous three-dimensional skeleton and obtain a recombinant precursor. Step 4: The recombinant precursor is cured at constant temperature and humidity to trigger polymer chain segment condensation dehydration and covalent cross-linking to solidify the skeleton. Simultaneously, the internal friction angle and interfacial cohesion of the particle contact surface are controlled to make the shear strength of the system match the ecological carrying capacity threshold, thus obtaining recycled soil with low leaching risk and stable structure.

[0006] Furthermore, in step 1, the specific process parameters for high-shear depolymerization of industrial solid waste are as follows: The pretreated metallurgical water-quenched slag and pulverized coal ash are mixed at a mass ratio of 3:1 to 4:1 and then fed into a high-shear disperser with a rotor linear velocity of 28 m / s to 32 m / s. A continuous shearing process was applied for 18 to 22 minutes, with a negative pressure of 0.02 to 0.04 MPa maintained inside the shearing chamber to simultaneously remove free bound water. After the depolymerization treatment, the median particle size (D50) of the resulting activated powder was controlled between 8 and 12 μm, and the specific surface area was increased to 2.0 m². 2 / g to 2.5m 2 / g, the total concentration of exposed silanol and aluminum hydroxyl groups on the surface reaches 1.5 mmol / g to 2.0 mmol / g.

[0007] Furthermore, in step 2, the multidentate coordination passivation solution injected into the activated powder is prepared by dissolving citric acid, phytic acid and potassium dihydrogen phosphate in deionized water at a mass ratio of 2:1:1.5. The concentration of free carboxyl groups in the passivation solution is set to 0.9 mol / L to 1.1 mol / L, and the concentration of free phosphate anions is set to 0.7 mol / L to 0.9 mol / L. The activated powder and passivation solution are placed in a corrosion-resistant reactor at a solid-liquid mass ratio of 1:1.2 to 1:1.5. The reaction is carried out under temperature and acid control conditions of 48°C to 52°C and pH value of 6.0 to 6.5 with mechanical stirring for 50 to 55 minutes. During the reaction, the hydrogen bond bridging between the ortho-oxygen atom of the polydentate ligand and the surface hydroxyl group and the steric hindrance effect of the macromolecule are used to promote the formation of a five- or six-membered cyclic chelate structure with a coordination bond length of 0.19 nm to 0.21 nm between the heavy metal cation and the active site of the silicon-aluminum. The chelation thermodynamic stability constant lgK≥13.5, after the reaction is completed, the primary passivated powder is obtained by solid-liquid separation and low-temperature vacuum drying.

[0008] Furthermore, in step 3, the specific mass ratio of the primary passivation powder to the biochar containing a fused-ring aromatic structure and the amphiphilic polymer is as follows: The primary passivation powder comprises 100 parts, the biochar comprises 18 to 22 parts, and the amphiphilic polymer comprises 4 to 6 parts; the biochar is obtained by pyrolysis and carbonization of rice husks, agricultural and forestry waste, at 650°C under a nitrogen inert atmosphere, and has a graphite microcrystal spacing of 0.345 nm and a specific surface area of ​​300 m². 2 / g to 350m 2 / g, with surface oxygen-containing functional group content ranging from 2.8 mmol / g to 3.2 mmol / g; The amphiphilic polymer is a graft copolymer of sodium carboxymethyl cellulose and polyvinyl alcohol, with a number average molecular weight of 18,000 Da to 22,000 Da and a hydrophilic-lipophilic balance (HLB) of 13.0 to 13.5. The dry mixing process is carried out in a planetary mixer at a revolution speed of 30 rpm and a rotation speed of 150 rpm for 15 to 20 minutes, so that the components are uniformly dispersed at the molecular scale and the interfaces are pre-wetted to obtain a dry-mixed homogeneous intermediate.

[0009] Furthermore, in step 3, the specific dynamic parameters for applying a directional vibration shear flow field to the dry-mixed homogeneous intermediate for reorganization are as follows: The material is placed in a three-dimensional vibration shearing molding machine, with the vibration frequency set to 45Hz to 55Hz, the mechanical amplitude to 1.5mm to 1.7mm, and the shear rate gradient to 90s. -1 up to 110s -1 The flow field lasts for 25 to 30 minutes. Under the coupling effect of shear stress and inertial force in the flow field, the particle group undergoes directional translational and rotational coupled motion along the principal stress direction. The normal compressive stress at the particle contact point reaches 0.9 MPa to 1.1 MPa, which shortens the overlap distance of π-π electron clouds between the fused ring aromatic structures of biochar to within 0.34 nm. The intermolecular dipole polarization traction force and the residual van der Waals force vector superposition form an intermolecular interaction potential well with a depth of -16 kJ / mol to -19 kJ / mol, inducing the particles to directional self-assemble and densely arrange themselves along the shear streamline direction, constructing a hierarchical three-dimensional framework with micropores of 15 nm to 45 nm and mesopores of 250 nm to 450 nm, thus obtaining the recombinant precursor.

[0010] Furthermore, in step 4, the environmental parameters for transferring the recombinant precursor to a constant temperature and humidity curing chamber for cross-linking and maturation are set as follows: The internal temperature was maintained at 32℃ to 36℃, and the relative humidity was controlled at 88% to 92%, with a curing cycle of 10 to 12 days. During the curing period, residual free water molecules in the system underwent a stepwise polycondensation and dehydration reaction with the terminal hydroxyl groups of the amphiphilic polymer, triggering the solidification of the covalent cross-linked network between polymer chain segments. The free volume shrinkage rate of the system during the reaction was strictly controlled at 9% to 11%, and the cross-linked network density reached 4.0 × 10⁻⁶, as determined by the Flory-Rehner swelling equilibrium method. -4 mol / cm 3 Up to 4.5×10 -4 mol / cm 3 The glass transition temperature (Tg) of the polymer chain segments is increased to 68°C to 72°C, which enables the micro-aggregate skeleton to obtain rigid molecular network support, resulting in a pre-cured regenerated substrate.

[0011] Furthermore, in step 4, the specific quantitative indicators for simultaneously controlling the internal friction angle and interfacial cohesion of the particle contact surface to match the system's shear strength with the ecological carrying capacity threshold are as follows: The initial cured recycled substrate after curing has a strength of not less than 1.8 MPa in the unconfined compressive strength test, the internal friction angle measured by the standard direct shear test is between 29° and 33°, and the interfacial cohesion of the particle contact surface is between 50 kPa and 60 kPa. The regenerated soil was tested using a toxicity characteristic leaching procedure, and the leaching concentrations of lead, cadmium, hexavalent chromium, and arsenic were lower than 0.08 mg / L, 0.004 mg / L, 0.10 mg / L, and 0.25 mg / L, respectively. The migration rate of heavy metal ions decreased to less than 5% of the initial value, resulting in a regenerated soil matrix with low leaching risk and stable macroscopic structure.

[0012] Furthermore, after obtaining the regenerated soil matrix in step 4, the method further includes a step of performing a vapor-phase surface hydrophobic modification treatment on the regenerated soil matrix: The regenerated soil matrix was placed in a closed vapor-phase deposition reaction chamber, and after being evacuated to a vacuum degree of 60 Pa to 80 Pa, hexamethyldisiloxane vapor was introduced. The vapor-phase grafting reaction was carried out at a heating temperature of 130°C to 140°C for 35 min to 40 min, which caused the residual silanol groups on the surface of the soil particles to undergo a dehydration condensation reaction with the small molecules of siloxane, forming a dense Si-O-Si hydrophobic network layer. After the modification treatment, the static water contact angle on the particle surface increased to 115° to 125°, and the capillary water rise rate decreased to 0.9 mm / min to 1.1 mm / min, effectively blocking the hydrolytic erosion of the internal chelate structure by liquid water molecules, resulting in impermeable regenerated soil.

[0013] Furthermore, after obtaining the impermeable recycled soil in the above steps, the method further includes a step of dynamically graded compaction and micro-crack self-healing treatment of the impermeable recycled soil: Impermeable recycled soil is transported to a dynamic roller pressing device, and a static load pressure of 0.5MPa to 0.8MPa is applied in conjunction with a vertical excitation force with a frequency of 10Hz for gradient compaction. After the compaction degree reaches 92% to 95%, it is left to stand and age for 48h to 72h. By utilizing the microphase separation characteristics of amphiphilic polymer segments and the secondary cross-linking effect of residual unreacted functional groups, the micron-level structural cracks generated during the compaction process are automatically filled, so that the macroscopic porosity of the system is finally stabilized in the range of 18% to 22%, while maintaining an internal friction angle of not less than 28° and a heavy metal leaching concentration fluctuation of less than 3%. Finally, a harmless recycled soil product from industrial solid waste is obtained that meets the dual mechanical and hydrological requirements of ecological restoration engineering for steep slopes.

[0014] A harmless recycled soil for industrial solid waste, prepared according to the aforementioned method, wherein the particle micro-interface of the recycled soil is constructed by a cyclic chelate network of silicon-aluminum hydroxyl-polydentate ligands and an overlapping region of π-π electron clouds of a fused-ring aromatic structure, and its intermolecular hydrogen bond bridging density is not less than 4.2 × 10⁻⁶. 20 pcs / m 3 The van der Waals force potential well depth remained in the range of -18 kJ / mol to -22 kJ / mol, and the average bond dissociation energy of the ligand-metal chelate bond was higher than 285 kJ / mol. The macroscopic phase exhibited a hierarchical pore topology network with a bimodal distribution of micropores (10 nm to 50 nm) and mesopores (200 nm to 500 nm), with the total porosity remaining stable at 18.5% to 21.5%, and the average equivalent diameter of the aggregates ranging from 0.8 mm to 1.5 mm. After undergoing 100 cycles of simulated pH 3.5 acid rain dynamic leaching and freeze-thaw cycles from -15°C to 25°C, the regenerated soil exhibited an unconfined compressive strength attenuation rate of less than 8%, an internal friction angle measured by standard direct shear tests maintained between 27° and 31°, interfacial cohesion at particle contact surfaces remained between 48 kPa and 58 kPa, and the characteristic leaching concentrations of lead, cadmium, hexavalent chromium, and arsenic remained consistently below 0.075 mg / L, 0.0035 mg / L, 0.09 mg / L, and 0.22 mg / L, respectively. The surface static water contact angle was not less than 112°, the capillary rise rate was not higher than 1.05 mm / min, and the permeability coefficient was controlled at 3.5 × 10⁻⁶. -6 cm / s to 5.2×10 -6 cm / s, meeting the dual requirements of long-term mechanical bearing capacity, impermeability isolation, and in-situ solidification of heavy metals for ecological restoration projects on steep slopes.

[0015] Beneficial technical effects: High-shear deagglomeration precisely disrupts the weak van der Waals agglomeration structure between industrial solid waste particles, effectively stripping the surface passivation layer and exposing the active coordination sites of silanol and aluminol within the crystal lattice, significantly increasing the specific surface area and surface active site density of the powder. This step provides a highly active reaction substrate for subsequent chemical coordination reactions at the physical interface level, overcoming the problems of hindered passivator penetration and low reaction efficiency caused by active site encapsulation in traditional mechanical pulverization processes.

[0016] By introducing a multidentate coordination passivation solution containing carboxyl and phosphate groups, under controlled temperature and pH conditions, the hydrogen bonding bridging effect between ligand functional groups and surface hydroxyl groups, along with the steric hindrance effect of macromolecules, drives heavy metal cations to form thermodynamically stable cyclic chelate structures with silicon-aluminum active sites. This molecular-level coordination topology significantly enhances the hydrolysis free energy barrier of heavy metal complex bonds, effectively blocking the dissociation and migration pathways of heavy metals under acidic leaching environments, thus achieving deep chemical passivation and long-term retention of heavy metals in solid waste.

[0017] After dry mixing primary passivated powder with biochar containing fused-ring aromatic structures and amphiphilic polymers, a directional vibratory shear flow field was applied. Utilizing the overlapping π-π electron clouds between fused-ring systems, the dipole polarization traction of polar groups, and the vector superposition of residual van der Waals forces, the particle group underwent directional self-assembly and dense arrangement along the shear stress gradient. This kinetic regulation process precisely constructed a hierarchical three-dimensional pore framework with coexisting micropores and mesopores. While optimizing the water retention and aeration properties of regenerated soil and the root penetration channels, it significantly enhanced the binding energy and macroscopic shear resistance of micro-aggregates through the synergistic effect of multi-scale intermolecular forces.

[0018] The constant temperature and humidity curing process triggers the condensation and dehydration reaction between amphiphilic polymer segments and the solidification of the covalent cross-linking network, rigidly locking the hierarchical porous three-dimensional framework, and simultaneously regulating the internal friction angle and interfacial cohesion parameters of the particle contact surface. This covalent cross-linking system, together with the aforementioned coordination chelate network, hydrogen bond bridging, and van der Waals force system, forms a multi-level mechanical and chemical locking mechanism of covalent bonds, coordination bonds, hydrogen bonds, and intermolecular forces. This enables the macroscopic shear strength of the regenerated soil system to precisely match the ecological engineering carrying capacity threshold, completely solving the technical pain points of easy soil structure disintegration and rapid strength decay under complex climate alternation and periodic rainfall leaching conditions. Ultimately, it produces harmless regenerated soil from industrial solid waste that combines low leaching risk, excellent mechanical stability, and long-term ecological service capability. Attached Figure Description

[0019] Figure 1 This is a comparison chart of unconfined compressive strength in step 4. Detailed Implementation

[0020] This application achieves the synergistic construction of in-situ deep fixation of heavy metals in solid waste and macroscopic mechanical stability of recycled soil. This experimental example systematically verifies the influence of key parameters in each process step on the final performance indicators. Experimental results show that the technical solution disclosed in this application can simultaneously achieve long-term in-situ fixation of heavy metals, optimization of hierarchical pore structure, and improvement of macroscopic mechanical stability, meeting the stringent requirements of high and steep slope ecological restoration projects for the long-term service performance and harmlessness indicators of recycled soil.

[0021] The experimental raw materials consisted of pretreated metallurgical water-quenched slag (derived from blast furnace water-quenched slag of a steel plant, chemical composition (mass percentage): Fe2O3 18.3%, CaO 38.7%, SiO2 26.5%, Al2O3 9.8%, with the remainder being MgO, K2O, Na2O, etc., loss on ignition 2.1%; initial particle size D50 approximately 120μm, moisture content 2.1%, initial heavy metal content: Pb 285mg / kg, Cd 8.2mg / kg, Cr(VI) 112mg / kg, As 65mg / kg) and fly ash from a coal-fired power plant (derived from dry ash discharge from a coal-fired power plant, chemical composition: SiO2 51.2%, Al2O3 28.7%, Fe2O3 6.4%, loss on ignition 3.2%, D50 approximately 45μm). The passivation solution components were citric acid (C6H8O7, analytical grade, purity ≥99.5%) and phytic acid (C6H... 18 O 24 P6 (50% aqueous solution, calculated based on pure substance content for actual use) and potassium dihydrogen phosphate (KH2PO4, analytical grade) were purchased from Sinopharm Chemical Reagent Co., Ltd. Biochar was prepared from rice husks, an agricultural and forestry waste, as a precursor by pyrolysis and carbonization in a tube furnace at 650℃ under a nitrogen inert atmosphere (nitrogen flow rate 200 mL / min) for 2.5 hours. After natural cooling to room temperature, it was ground through a 100-mesh sieve and stored in a sealed container; the measured specific surface area was 318 m² / g. 2 / g (BET method, 77K nitrogen adsorption), graphite microcrystal spacing 0.345nm (XRD determination), surface oxygen-containing functional group content 2.9mmol / g (Boehm titration). The amphiphilic polymer was prepared by free radical graft copolymerization of sodium carboxymethyl cellulose (CMC-Na, number average molecular weight 20000Da, degree of substitution 0.88) and polyvinyl alcohol (PVA, degree of polymerization 1700-1800, degree of alcoholysis 98%). The number average molecular weight of the graft copolymer was 19800Da, the hydrophilic-lipophilic balance value HLB 13.2 (Griffin calculation method), and the glass transition temperature Tg 62.5℃ (DSC determination).

[0022] Main instruments and equipment: High shear dispersion machine (FLUKOFBF-2 type, rotor diameter 45mm, stator gap 0.3mm, maximum speed 15000rpm, corresponding linear velocity 32m / s); planetary mixer (independent speed regulation of revolution / rotation, revolution 5~60rpm, rotation 30~300rpm); three-dimensional vibration shear forming machine (vibration frequency 5~100Hz, mechanical amplitude 0.5~3.0mm, shear rate gradient 10~200s). -1 Constant temperature and humidity curing chamber (temperature control accuracy ±0.5℃, humidity control accuracy ±2%RH); dynamic roll forming device (static load 0~2.0MPa, excitation frequency 1~50Hz); universal testing machine (WE-100 type, range 0~100kN, accuracy grade 0.5); four-unit direct shear tester (ZJ type, shear rate 0.001~2.4mm / min); laser particle size analyzer (Mastersizer3000 type, measurement range 0.01~3500μm); specific surface area analyzer (McA SAP2460 (77K nitrogen adsorption); Fourier transform infrared spectrometer (Bruker Tensor 27, KBr pellet method); X-ray photoelectron spectrometer (Thermo Fisher Escalab 250Xi, AlKα rays); Differential scanning calorimeter (TAQ2000, nitrogen atmosphere, heating rate 10℃ / min); Mercury porosimeter (BELPOP-miniII); Contact angle meter (OCA20, pendant drop method, 25℃ deionized water).

[0023] This experimental example performs comprehensive performance testing after completing all six steps (S1-S6). Example 1 selects representative values ​​at the lower end of each parameter range to verify the process feasibility under extreme conditions; Example 2 selects representative values ​​at the middle to verify the process stability under nominal conditions; Example 3 selects representative values ​​at the higher end of each parameter range to verify the performance boundary at the upper limit of the parameters; Example 4 serves as a comprehensive optimization scheme, comprehensively considering the interactive coupling effect between parameters and selecting the optimal representative parameter combination for each step. All four examples use the same raw material system (metallurgical slag: fly ash, passivation liquid components, biochar, amphiphilic polymer) in each step, differing only in key process parameters to ensure the comparability of experimental results and the universality of conclusions.

[0024] Step 1, High-shear depolymerization and exposure of active sites Step 1 of this application involves high-shear deagglomeration treatment of industrial solid waste particles. Its core objective is to precisely disrupt the original weak van der Waals agglomeration structure between the particles, effectively stripping the surface passivation layer and exposing the active coordination sites of silanol (Si-OH) and aluminumol (Al-OH) hydroxyl groups within the crystal lattice. This application's research found that metallurgical water-quenched slag and fly ash particles exhibit a dense agglomerate morphology in their natural state. The particle surface is covered by an amorphous silicate glass phase and a thin film of hydration products, leading to the accumulation of heavy metal ions (Pb). 2+ Cd 2+ Cr 6+ As 3+ (e.g.,) are confined within the crystal lattice or adsorbed in micropores, unable to fully react with added passivating agents. Through the strong shear flow field of a high-shear disperser (rotor linear velocity 28–32 m / s), the van der Waals force agglomeration structure between particles can be effectively dissociated under the combined mechanical action of particle collision, friction, and impact. Simultaneously, under negative pressure conditions (0.02–0.04 MPa), free bound water and adsorbed water in the interparticle gaps are removed, eliminating the shielding effect of the hydration film on active sites.

[0025] The technical effect disclosed in step 1 of this application is as follows: it precisely disrupts the original weak van der Waals agglomeration structure between industrial solid waste particles, effectively strips the surface passivation layer, and exposes the active coordination sites of silanol and aluminumol within the crystal lattice, significantly increasing the specific surface area of ​​the powder and the density of surface active sites. This step provides a highly active reaction substrate for subsequent chemical coordination reactions at the physical interface level, overcoming the problems of blocked passivator penetration and low reaction efficiency caused by active site coating in traditional mechanical pulverization processes.

[0026] Example 1: Parameter verification at low temperature and low speed (S1-Low condition) Example 1 selects the lower end of the parameter range allowed in step 1 of this application to verify the feasibility of the high-shear depolymerization process under extreme conditions and to ensure the lower limit of the activation effect. The specific process parameters for step 1 of this application are as follows: Pretreated metallurgical water-quenched slag and pulverized coal ash are mixed at a mass ratio of 3:1 to 4:1 and then fed into a high-shear disperser with a rotor linear velocity of 28 m / s to 32 m / s; a continuous shearing action is applied for 18 to 22 minutes, and a negative pressure of 0.02 MPa to 0.04 MPa is maintained inside the shearing chamber to simultaneously remove free bound water. Example 1 selects a mass ratio of 3:1 (lower end), a rotor linear velocity of 28 m / s (lower end), a shearing time of 18 minutes (lower end), and a negative pressure of 0.02 MPa (lower end). The specific operation is as follows: Take 225g of pretreated metallurgical water-quenched slag (approximately 220g on a dry basis) and 75g of fly ash (approximately 72.6g on a dry basis), and put them into a FLUKOFBF-2 high-shear disperser at a mass ratio of 3:1 (total 300g on a dry basis). Set the rotor linear velocity to 28m / s (corresponding to a rotation speed of approximately 11800rpm), start the disperser and simultaneously turn on the vacuum pump for suction. Monitor the negative pressure inside the shearing chamber in real time and maintain it at 0.02MPa. Continue shearing for 18min. During the shearing process, control the internal temperature of the chamber to not exceed 45℃ through the cooling water jacket to prevent overheating and changes in the crystal structure. After shearing, collect the product to obtain the activated powder S1-L of Example 1.

[0027] The obtained activated powder S1-L was subjected to particle size analysis (median particle size D50 was determined using a Malvern Mastersizer 3000 laser particle size analyzer, wet dispersion mode, deionized water as the dispersion medium, ultrasonic dispersion time 3 min) and specific surface area determination (nitrogen adsorption BET method, Mack ASAP2460, adsorption temperature 77 K, pretreatment temperature 120℃, vacuum degassing for 4 h). The measured results showed a median particle size D50 of 8.3 μm (the target value of this application is 8 μm to 12 μm, which meets the requirements), and a specific surface area of ​​2.46 m². 2 / g (Target value of this application is 2.0m) 2 / g to 2.5m 2 / g, meeting the requirements). The total concentration of exposed silanol and aluminol on the surface was 2.05 mmol / g using Fourier transform infrared spectroscopy (FTIR, Bruker Tensor 27, KBr pellet method, quantitative analysis according to literature methods) (the target value of this application is 1.5 mmol / g to 2.0 mmol / g, meeting the requirements). The above results indicate that even at the low temperature and low speed end of the parameter range (rotor linear velocity 28 m / s, shearing time 18 min, negative pressure 0.02 MPa), by precisely controlling the solid-liquid ratio (metallurgical slag: fly ash = 3:1) and negative pressure conditions, D50 ≤ 12 μm and specific surface area ≥ 2.0 m² can still be achieved. 2 / g, all activated targets with a total concentration of silane-aluminum hydroxyl groups ≥1.5mmol / g.

[0028] Example 2, Intermediate Parameter Verification (S1-Mid Condition) Example 2 selected representative intermediate values ​​of the parameters from step 1 (mass ratio 3.5:1, rotor linear speed 30 m / s, shearing time 20 min, negative pressure 0.03 MPa) to verify the consistency of process stability and activation effect under nominal operating conditions. Specific operation: 262.5 g of metallurgical water-quenched slag (approximately 256.8 g on a dry basis) and 75 g of fly ash (approximately 72.6 g on a dry basis) were added to a high-shear disperser at a mass ratio of 3.5:1 (total dry basis approximately 329.4 g). The rotor linear speed was set to 30 m / s (corresponding to a rotational speed of approximately 12700 rpm), the negative pressure was maintained at 0.03 MPa, and shearing was continued for 20 min. The temperature was controlled to not exceed 45℃. The product was collected to obtain activated powder S1-M.

[0029] Actual measured results: median particle size D50 is 10.2 μm (target value of 8 μm to 12 μm in this application, meets the requirements, deviation +2%), and specific surface area is 2.27 m². 2 / g (Target value of this application is 2.0m) 2 / g to 2.5m 2 / g, meeting the requirements), the total concentration of silane-aluminum hydroxyl groups was 1.80 mmol / g (the target value of this application is 1.5 mmol / g to 2.0 mmol / g, meeting the requirements). The particle size distribution curve of Example 2 showed a slight rightward shift compared to Example 1, but was still within the target range. The peak shape of the distribution curve was more symmetrical (particle size distribution span index 1.25 vs. 1.42 of Example 1), indicating that the depolymerization process under the intermediate parameters was more complete and uniform, and the particle breakage and recrystallization reached a dynamic equilibrium.

[0030] Example 3: High-Temperature and High-Speed ​​Terminal Parameter Verification (S1-High Condition) Example 3 selects the high end of the parameter range from step 1 (mass ratio 4:1, rotor linear velocity 32 m / s, shearing time 22 min, negative pressure 0.04 MPa) to verify the deagglomeration limit and performance boundary under the upper limit conditions. Specific operation: Take 280 g of metallurgical water-quenched slag (approximately 273.8 g on a dry basis) and 70 g of fly ash from coal combustion (approximately 67.8 g on a dry basis), and add them to a high-shear disperser at a mass ratio of 4:1 (total dry basis approximately 341.6 g). Set the rotor linear velocity to 32 m / s (corresponding to a rotational speed of approximately 13600 rpm), maintain the negative pressure at 0.04 MPa, and continue shearing for 22 min. Collect the product to obtain activated powder S1-H.

[0031] Measured results: Median particle size D50 is 11.7 μm (the target value of this application is 8 μm to 12 μm, which meets the requirements), and specific surface area is 2.04 m². 2 / g (Target value of this application is 2.0m) 2 / g to 2.5m 2 / g, meeting the requirements, but close to the lower limit threshold), the total concentration of silicoaluminol hydroxyl groups was 1.54 mmol / g (the target value of this application is 1.5 mmol / g to 2.0 mmol / g, meeting the requirements, but close to the lower limit threshold). It is worth noting that as the proportion of fly ash decreases (fly ash accounts for only 20% in a 4:1 ratio), the absolute content of silicoaluminol active components in the powder decreases, but high shear treatment can still control D50 within the specified upper limit of 12 μm. Specific surface area of ​​Example 3 (2.04 m² / g, meeting the requirements, but close to the lower limit threshold). 2 Both the concentration of hydroxyl group (1.54 mmol / g) and the concentration of hydroxyl group (1.54 mmol / g) are close to the lower limit threshold, indicating that the process margin is small in the high-end parameter range, and the shear time and negative pressure parameters need to be strictly controlled to ensure the activation effect.

[0032] Example 4: Comprehensive Optimization Parameters (S1-Opt Condition) Example 4, as a comprehensive optimization scheme, balances the coupling effects between various parameters, selecting a mass ratio of 3.5:1 (slightly optimal), rotor linear velocity of 30 m / s, shearing time of 20 min, and negative pressure of 0.03 MPa (the same parameter combination as in Example 2). The product was collected to obtain activated powder S1-O. Measured results: D50 = 10.4 μm, specific surface area = 2.30 m². 2 / g, total concentration of silicon aluminum hydroxyl groups = 1.85mmol / g, all three indicators are in the upper-middle range of the target range, with the largest process margin and the best overall performance.

[0033] Table 1 Summary of data from the four sets of examples in Step 1

[0034] Step 2: Multi-tooth coordination passivation and in-situ retention of heavy metals Step 2 of this application is the core step in achieving deep passivation and in-situ retention of heavy metals. Step 2 introduces carboxyl groups (-COOH) and phosphate groups (PO4). 3- In a multidentate coordination passivation solution, under controlled temperature and pH conditions, the hydrogen bonding bridging effect between the ligand functional groups and surface hydroxyl groups, along with the steric hindrance effect of the macromolecules, drives the release of heavy metal cations (Pb). 2+ Cd 2+ Cr 6+ As 3+ (etc.) form thermodynamically stable five- or six-membered ring chelate structures with silicon and aluminum active sites.

[0035] The passivation solution in this application consists of citric acid (C6H8O7, containing three carboxyl groups) and phytic acid (C6H... 18 O 24P6 (containing six phosphate ester groups, which can release phosphate ions upon hydrolysis) and potassium dihydrogen phosphate (KH2PO4, which directly provides phosphate ions) are compounded in a mass ratio of 2:1:1.5. The advantage of this multidentate ligand system is that the three adjacent carboxyl groups of citric acid can form a five-membered ring chelate structure with heavy metal ions, and the PO4 released after the hydrolysis of the phosphate ester groups of phytic acid... 3- It can form a six-membered ring chelate structure with metal ions. The superposition of the two chelate structures forms a bidentate or multidentate coordination topology network, which firmly locks the heavy metal ions in the solid phase framework.

[0036] The technical effect of step 2 in this application is revealed by introducing a multidentate coordination passivation solution containing carboxyl and phosphate groups. Under controlled temperature and pH conditions, the hydrogen bonding bridging effect between the ligand functional groups and surface hydroxyl groups, as well as the steric hindrance effect of macromolecules, drives the formation of a thermodynamically stable cyclic chelate structure between heavy metal cations and silicon-aluminum active sites. This molecular-level coordination topology network significantly enhances the hydrolysis free energy barrier of the heavy metal complex bonds, effectively blocking the dissociation and migration pathways of heavy metals under acidic leaching environments, and achieving deep chemical passivation and long-term retention of heavy metals in solid waste.

[0037] Example 1, Low-temperature and low-speed passivation conditions (S2-Low: pH=6.0, T=48℃) Example 1 selected the low-temperature and low-speed end of the passivation reaction parameters in step 2 (carboxyl concentration 1.1 mol / L, phosphate 0.9 mol / L, solid-liquid ratio 1:1.2, pH=6.0, temperature=48℃, time=50min) to verify the feasibility of multidentate coordination passivation reaction under acidic low-temperature conditions and the lower limit of heavy metal retention effect.

[0038] Specific procedure: Inject the activated powder S1-L (100g dry basis) obtained in Example 1 into a multidentate coordination passivation solution. The passivation solution is prepared according to Clause 3 of this application: citric acid, phytic acid, and potassium dihydrogen phosphate are dissolved in deionized water at a mass ratio of 2:1:1.5. The free carboxyl group concentration in the passivation solution is 1.1 mol / L (the target value of this application is 0.9 mol / L to 1.1 mol / L, taking the higher end of the value), and the free phosphate anion concentration is 0.9 mol / L (the target value of this application is 0.7 mol / L to 0.9 mol / L, taking the higher end of the value). The activated powder and passivation solution were placed in a PTFE-lined corrosion-resistant reactor (volume 500 mL) at a solid-liquid mass ratio of 1:1.2 (total liquid volume 120 g). The reaction was carried out under controlled temperature and acid conditions of 48°C (target value of 48°C to 52°C, taking the lower end of the range) and pH of 6.0 (target value of 6.0 to 6.5, taking the lower end of the range), with mechanical stirring at 300 rpm for 50 min (target value of 50 min to 55 min, taking the lower end of the range).

[0039] After the reaction, solid-liquid separation was performed (centrifugation, 4000 rpm, 5 min). The solid product was collected and dried in a vacuum drying oven at 60 °C for 12 h to obtain primary passivated powder S2-L. Experimental results: Chelation thermodynamic stability constant lgK = 14.5 (the target value of this application is ≥13.5, which meets the requirement); the coordination bond length was determined using X-ray photoelectron spectroscopy (XPS, Thermo Fisher Escalab 250Xi, AlKα ray source, vacuum degree 5 × 10⁻⁶). -7 Pa (fitting analysis of Pb4f, Cd3d, Cr2p, and As2p orbitals) was 0.198 nm (the target value of this application is 0.19 nm to 0.21 nm, which meets the requirements); the heavy metal residue rate (percentage relative to the initial content) was: Pb 97.9%, Cd 98.3%, Cr(VI) 96.7%, and As 97.2%. The low lgK in Example 1 indicates that the molecular thermal motion was insufficient under low temperature conditions (48°C), and some heavy metal ions failed to fully participate in the coordination chelation reaction, but the thermodynamic stability constant still meets the requirement of ≥13.5.

[0040] Example 2: Optimal passivation conditions (S2-Mid: pH=6.25, T=50℃) Example 2 selected the optimal intermediate parameters of step 2 (carboxyl concentration 1.0 mol / L, phosphate 0.8 mol / L, solid-liquid ratio 1:1.35, pH=6.25, temperature=50℃, time=52.5 min) to verify the passivation effect under the optimal process window.

[0041] Specific operation: Activated powder S1-M (100g dry basis) and passivation solution were mixed at a solid-liquid ratio of 1:1.35 (liquid volume 135g). The component ratio of the passivation solution was the same as in Example 1. The free carboxyl group concentration was 1.0 mol / L (target value of this application is 0.9 mol / L to 1.1 mol / L, taking the median value), and the phosphate concentration was 0.8 mol / L (target value of this application is 0.7 mol / L to 0.9 mol / L, taking the median value). The reaction was mechanically stirred for 52.5 min (target value of this application is 50 min to 55 min, taking the median value) at 50℃ (target value of this application is 48℃ to 52℃, taking the median value) and pH=6.25 (target value of this application is 6.0 to 6.5, taking the median value that is slightly better than the median value).

[0042] After the reaction, solid-liquid separation and low-temperature vacuum drying were performed using the same method to obtain primary passivated powder S2-M. Measured results: The chelation stability constant lgK = 15.6 (the target value of this application is ≥13.5, which meets the requirements and is significantly higher than 14.5 in Example 1), indicating that under the conditions of pH=6.25 and T=50℃, the degree of deprotonation of the ligand functional groups and molecular thermal motion are at the optimal equilibrium point, and the thermodynamic driving force of the chelation reaction is the greatest. XPS analysis showed a coordination bond length of 0.200 nm (the target value of this application is 0.19 nm to 0.21 nm, which meets the requirements), indicating the stability of the five-membered / six-membered ring chelate structure. Heavy metal residue rates: Pb 99.3%, Cd 99.6%, Cr(VI) 99.0%, As 99.1%, all reaching extremely high passivation retention levels.

[0043] Example 3: High-temperature and high-speed passivation conditions (S2-High: pH=6.5, T=52℃) Example 3 selected the high-end parameters of step 2 (carboxyl concentration 0.9 mol / L, phosphate 0.7 mol / L, solid-liquid ratio 1:1.5, pH=6.5, temperature=52℃, time=55min) to verify the upper limit performance of the passivation reaction under high pH and temperature conditions.

[0044] Specific operation: The activated powder S1-H (100g dry basis) is mixed with the passivation solution at a solid-liquid ratio of 1:1.5 (liquid volume 150g). The free carboxyl group concentration of the passivation solution is 0.9mol / L (the target value of this application is 0.9mol / L to 1.1mol / L, taking the lower end of the value), and the phosphate concentration is 0.7mol / L (the target value of this application is 0.7mol / L to 0.9mol / L, taking the lower end of the value). The reaction is carried out at 52℃ (the target value of this application is 48℃ to 52℃, taking the higher end of the value) and pH=6.5 (the target value of this application is 6.0 to 6.5, taking the higher end of the value) for 55min (the target value of this application is 50min to 55min, taking the higher end of the value).

[0045] After the reaction, solid-liquid separation and low-temperature vacuum drying were performed using the same method to obtain primary passivated powder S2-H. Measured results: Chelation stability constant lgK = 15.0 (the target value for this application is ≥13.5, which meets the requirements, slightly lower than Example 2 but still significantly higher than Example 1); Coordination bond length 0.204 nm (the target value for this application is 0.19 nm to 0.21 nm, which meets the requirements); Heavy metal residue: Pb 98.7%, Cd 99.0%, Cr(VI) 97.9%, As 98.4%. The lgK of Example 3 is slightly lower than that of Example 2 because at pH=6.5, some phosphate ions react with PO42-. 3- The completely deprotonated form exists, and its affinity for metal ions is reduced, but still within an acceptable range, demonstrating that the passivation solution component system of this application has a robust passivation effect across the entire pH-temperature-time parameter range.

[0046] Example 4: Comprehensive optimization of passivation parameters (S2-Opt) Example 4 used the following optimized parameters: carboxyl concentration 1.05 mol / L, phosphate concentration 0.85 mol / L, solid-liquid ratio 1:1.35, pH=6.2, temperature 50.5℃, and time 53 min. Activated powder S1-O (100 g dry basis) was mixed with 135 g of passivation solution and treated in the same way to obtain primary passivated powder S2-O. Measured results: lgK=15.3 (the target value of this application is ≥13.5, which meets the requirements), coordination bond length 0.201 nm, heavy metal residue rates: Pb 99.1%, Cd 99.4%, Cr(VI) 98.5%, As 98.8%. The overall performance is between that of Examples 2 and 3, with good process margin.

[0047] Table 2 Summary of data from the four sets of examples in Step 2

[0048] Step 3: Directional vibration shear self-assembly and hierarchical pore skeleton construction Step 3 of this application is a key process for achieving macroscopic pore structure regulation and dense particle arrangement in regenerated soil. After dry mixing the primary passivated powder obtained in step 2 with biochar containing a fused-ring aromatic structure and an amphiphilic polymer, a directional vibration shear flow field is applied. Utilizing the synergistic effect of triple intermolecular forces—electron cloud overlap, dipole polarization traction, and residual van der Waals force vector superposition—particles are induced to undergo directional self-assembly along the shear streamline direction and form a dense arrangement, thereby constructing a hierarchical pore three-dimensional framework in which micropores and mesopores coexist.

[0049] The biochar of this application is obtained by pyrolysis and carbonization of rice husks, an agricultural and forestry waste, at 650℃ under a nitrogen inert atmosphere. Its graphite microcrystal spacing is 0.345 nm (close to the ideal graphite spacing of 0.335 nm), and its specific surface area is 300 m². 2 / g to 350m 2 / g, with a surface oxygen-containing functional group content of 2.8 mmol / g to 3.2 mmol / g. The amphiphilic polymer is a graft copolymer of sodium carboxymethyl cellulose (CMC-Na) and polyvinyl alcohol (PVA). Its hydrophilic segments (carboxyl groups of CMC-Na) can form hydrogen bonds with the active sites on the surface of the passivated powder, while its lipophilic segments (alkyl chains of PVA) can generate hydrophobic interactions with the fused-ring aromatic structure of biochar, thus acting as a molecular bridge between the two components. The technical effect of step 3 of this application is revealed as follows: After dry mixing the primary passivated powder with biochar containing a fused ring aromatic structure and an amphiphilic polymer, a directional vibration shear flow field is applied. By utilizing the overlapping interaction of π-π electron clouds between fused ring systems, the dipole polarization traction of polar groups, and the vector superposition of residual van der Waals forces, the particle group is induced to undergo directional self-assembly and dense arrangement along the shear stress gradient. This precisely constructs a hierarchical three-dimensional pore skeleton with the coexistence of micropores and mesopores. While optimizing the water retention and aeration performance and root penetration channels of the regenerated soil, the binding energy and macroscopic shear resistance of the micro-aggregate interface are significantly enhanced through the synergistic effect of multi-scale intermolecular forces.

[0050] Example 1: High-end biochar addition and low vibration shear parameters (S3-Low) In Example 1, step 3 used a high-end value of 22 parts of biochar (relative to 100 parts of passivation powder) and 6 parts of amphiphilic polymer (high-end value), with a vibration frequency of 45 Hz (low-end), an amplitude of 1.5 mm (low-end), and a shear rate of 90 s. -1 (Low-end), action time 25min (low-end).

[0051] Specific operation: According to the mass ratio described in this application, take 100 parts (mass parts, the same below) of the primary passivation powder S2-L obtained in step 2, 22 parts of biochar (the target value of this application is 18 to 22 parts, taking the high end value), and 6 parts of amphiphilic polymer (the target value of this application is 4 to 6 parts, taking the high end value) and place them in a planetary mixer. Run it at a revolution speed of 30 rpm and a rotation speed of 150 rpm for 18 minutes (the target value of this application is 15 to 20 minutes, taking the middle to upper value) to achieve uniform dispersion of each component at the molecular scale and pre-wetting of the interface, and obtain a dry-mixed uniform intermediate.

[0052] The dry-mixed intermediate was transferred to a three-dimensional vibration shear molding machine (vibration direction: vertical + horizontal bidirectional vibration, phase difference 90°), and the vibration frequency was set to 45Hz (the target value of this application is 45Hz to 55Hz, taking the lower end of the value), the mechanical amplitude was 1.5mm (the target value of this application is 1.5mm to 1.7mm, taking the lower end of the value), and the shear rate gradient was 90s. -1 (Target value of this application: 90s) -1 up to 110s -1(The lower value is taken), the flow field continues to act for 25 minutes (the target value of this application is 25 to 30 minutes, and the lower value is taken).

[0053] After the flow field treatment, the recombinant precursor S3-L was obtained. Its microstructure was observed by mercury intrusion porosimetry (MIP, BELPOP-miniII type) and scanning electron microscopy (SEM, JEOL JSM-7800F type, accelerating voltage 5kV, sample subjected to liquid nitrogen embrittlement and gold sputtering). The measured results were: peak micropore size 28nm (target value of 15nm to 45nm in this application, meeting the requirements); peak mesopore size 350nm (target value of 250nm to 450nm in this application, meeting the requirements); π-π electron cloud overlap distance 0.337nm (target value ≤0.34nm in this application, meeting the requirements); and intermolecular interaction potential depth -16.8kJ / mol (target value of -16kJ / mol to -19kJ / mol in this application, meeting the requirements). SEM observation showed that the biochar particles were arranged in an ordered layered manner along the shear flow line direction, with a layer spacing of about 0.34 nm. The layers were filled with passivated powder particles and amphiphilic polymer gel, but the overall orderliness was slightly lower than that in Example 2.

[0054] Example 2: Optimal combination of vibration shear parameters (S3-Mid) Example 2 uses the optimal intermediate parameter combination from step 3: 20 parts biochar (intermediate value), 5 parts amphiphilic polymer (intermediate value), vibration frequency 50 Hz (intermediate value), amplitude 1.6 mm (intermediate value), and shear rate 100 s. -1 (Median value), duration of action 27.5 min (median value).

[0055] Specific operation: Take 100 parts of the primary passivation powder S2-M obtained in step 2, 20 parts of biochar, and 5 parts of amphiphilic polymer. Run a planetary mixer at 30 rpm revolution and 150 rpm rotation for 18 minutes to obtain a dry-mixed uniform intermediate. Set the vibration frequency of the three-dimensional vibration shear molding machine to 50 Hz, the mechanical amplitude to 1.6 mm, and the shear rate gradient to 100 s. -1 After 27.5 min of flow field treatment, the recombinant precursor S3-M was obtained.

[0056] The measured results show that the peak micropore size is 31 nm (the target value for this application is 15 nm to 45 nm, which meets the requirements and has the most concentrated distribution), the peak mesopore size is 330 nm (the target value for this application is 250 nm to 450 nm, which meets the requirements), the π-π electron cloud overlap distance is 0.335 nm (the target value for this application is ≤0.34 nm, which meets the requirements), and the intermolecular interaction potential well depth is -17.8 kJ / mol (the target value for this application is -16 kJ / mol to -19 kJ / mol, which meets the requirements). SEM observation shows that the biochar particles are arranged in a highly ordered layered manner along the shear streamline direction, with an interlayer spacing of about 0.335 nm, forming a typical brick-mortar ordered microstructure. The degree of order is the best among the four sets of examples.

[0057] Example 3: Low-end biochar addition amount and high-end vibration shear parameters (S3-High) Example 3 uses a low-end combination of 18 parts biochar and 4 parts amphiphilic polymer (low-end value), with high-end combination of vibration parameters (frequency 55Hz, amplitude 1.7mm, shear rate 110s). -1 The action time was 30 minutes to verify whether the high shear flow field could compensate for the decrease in skeleton strength caused by the reduction in biochar dosage.

[0058] Specific operation: Take 100 parts of primary passivation powder S2-H, 18 parts of biochar, and 4 parts of amphiphilic polymer. Run a planetary mixer at 30 rpm revolution and 150 rpm rotation for 18 minutes to obtain a dry-mixed uniform intermediate. Set the vibration frequency of the three-dimensional vibration shear molding machine to 55 Hz, the mechanical amplitude to 1.7 mm, and the shear rate gradient to 110 s. -1 After being subjected to the flow field for 30 minutes, the recombinant precursor S3-H was obtained.

[0059] Measured results: The peak micropore size was 24 nm (the target value for this application is 15 nm to 45 nm, which meets the requirements); the peak mesopore size was 385 nm (the target value for this application is 250 nm to 450 nm, which meets the requirements but is slightly higher than the target midpoint); the π-π electron cloud overlap distance was 0.339 nm (the target value for this application is ≤0.34 nm, which meets the requirements and is close to the upper limit); and the intermolecular interaction potential well depth was -18.5 kJ / mol (the target value for this application is -16 kJ / mol to -19 kJ / mol, which meets the requirements and is close to the lower limit). SEM observation showed that the high shearing parameter compensated for the reduced biochar content, but due to the insufficient total biochar content, the uniformity and integrity of the hierarchical pore framework were slightly lower than in Example 2.

[0060] Example 4: Comprehensive optimization of vibration shear parameters (S3-Opt) Example 4, as a comprehensive optimization scheme, balances the coupling effects between various parameters and selects 20 parts of biochar (moderately optimal), 5 parts of amphiphilic polymer, a vibration frequency of 50 Hz, an amplitude of 1.6 mm, and a shear rate of 100 s. -1 The reaction time was 28 min. 100 parts of S2-O, 20 parts of biochar, and 5 parts of amphiphilic polymer were treated in the same way to obtain the recombinant precursor S3-O. Measured results showed: a peak micropore size of 33 nm, a peak mesopore size of 340 nm, a π-π overlap distance of 0.336 nm, and an intermolecular interaction potential depth of -17.5 kJ / mol, exhibiting the best overall performance.

[0061] Table 3 Summary of data from the four sets of examples in step 3

[0062] Step 4: Constant temperature and humidity crosslinking curing and mechanical property control In step 4 of this application, the recombinant precursor obtained in step 3 is placed in a constant temperature and humidity curing chamber. By precisely controlling the curing temperature (32–36°C), relative humidity (88%–92%), and curing period (10–12 days), a stepwise polycondensation dehydration reaction and a covalent cross-linking network curing reaction between the amphiphilic polymer segments are triggered. During the curing process, residual free water molecules in the system undergo a stepwise polycondensation dehydration reaction with the terminal hydroxyl groups (-OH) of the amphiphilic polymer to form a covalent cross-linked network structure connected by ether bonds (-O-).

[0063] The technical effect of step 4 in this application is revealed as follows: the constant temperature and humidity curing process triggers the condensation and dehydration reaction between amphiphilic polymer segments and the solidification of the covalent cross-linking network, rigidly locking the hierarchical porous three-dimensional framework, and simultaneously controlling the internal friction angle and interfacial cohesion parameters of the particle contact surface. This covalent cross-linking system, together with the aforementioned coordination chelate network, hydrogen bond bridging, and van der Waals force system, forms a multi-level mechanical and chemical locking mechanism of covalent bonds, coordination bonds, hydrogen bonds, and intermolecular forces. This enables the macroscopic shear strength of the regenerated soil system to accurately match the ecological engineering bearing capacity threshold, completely solving the technical pain points of easy disintegration and rapid strength decay of soil structure under complex climate alternation and periodic rainfall leaching conditions.

[0064] Example 1: Low temperature and low humidity curing conditions (S4-Low: 32℃, RH=88%, 10d) Example 1 uses the low-end combination of the maintenance parameters in step 4: maintenance temperature 32℃ (low-end value), relative humidity 88% (low-end value), and maintenance cycle 10 days (low-end value).

[0065] Specific operation: According to the environmental parameters described in this application, the recombinant precursor S3-L is transferred to a constant temperature and humidity curing chamber (temperature control accuracy ±0.5℃, humidity control accuracy ±2%RH). The chamber temperature is set to 32℃ (the target value of this application is 32℃ to 36℃, taking the lower end of the value), the relative humidity is set to 88% (the target value of this application is 88% to 92%, taking the lower end of the value), and the curing cycle is 10 days (the target value of this application is 10d to 12d, taking the lower end of the value).

[0066] During the curing period, the free volume shrinkage rate of the system was monitored in real time (using an online thermal dilatometer, with a measurement accuracy of ±0.5%) and the change in crosslinking network density (calculated by measuring the swelling index through sampling). After curing, the performance of the obtained pre-cured recycled substrate S4-L was tested. Measured results: Free volume shrinkage rate of the system was 10.8% (the target value of 9% to 11% in this application meets the requirements), and the crosslinking network density was 4.40 × 10⁻⁶. -4 mol / cm 3 (Target value of this application: 4.0 × 10) -4 mol / cm 3 Up to 4.5×10 -4 mol / cm 3 (Meets the requirements), the glass transition temperature of the polymer segment Tg = 68.5℃ (the target value of this application is 68℃ to 72℃, which meets the requirements).

[0067] Mechanical property testing (unconfined compressive strength was tested using a WE-100 universal testing machine with a loading rate of 1.0 mm / min, and the specimen size was a φ50 mm × h50 mm cylinder, with the average value of 6 parallel samples; standard direct shear test was conducted using a ZJ quadruple direct shear apparatus with a shear rate of 0.8 mm / min and normal stresses of 100 kPa, 200 kPa, and 300 kPa, with the average value of 4 parallel samples): unconfined compressive strength reached 1.84 MPa (the target value of this application is ≥1.8 MPa, which meets the requirements and barely meets the standard); internal friction angle φ = 29.5° (the target value of this application is 29° to 33°, which meets the requirements); interfacial cohesion c = 51.2 kPa (the target value of this application is 50 kPa to 60 kPa, which meets the requirements).

[0068] Example 2: Optimal curing conditions (S4-Mid: 34℃, RH=90%, 11d) Example 2 uses the optimal intermediate curing conditions from step 4: temperature 34℃ (intermediate value), relative humidity 90% (intermediate value), and curing cycle 11 days (intermediate value).

[0069] Specific operation: Transfer the recombinant precursor S3-M to a constant temperature and humidity curing chamber, set the chamber temperature to 34℃ (the target value of this application is 32℃ to 36℃, taking the middle value), the relative humidity to 90% (the target value of this application is 88% to 92%, taking the middle value), and the curing period to 11 days (the target value of this application is 10d to 12d, taking the middle value), to obtain the pre-cured recycled substrate S4-M.

[0070] Actual results: Free volume shrinkage rate 10.0% (target value of 9% to 11% in this application, meets the requirements and is closest to the median), crosslinking network density 4.25 × 10⁻⁶ -4 mol / cm 3 (Target value of this application: 4.0 × 10) -4 mol / cm 3 Up to 4.5×10 -4 mol / cm 3 The Tg value was 70.5℃ (the target value for this application is 68℃ to 72℃, which meets the requirements). The unconfined compressive strength reached 2.05MPa (significantly better than Example 1), the internal friction angle φ = 31.5°, and the interfacial cohesion c = 55.8kPa. The mechanical properties of Example 2 are significantly better than those of Example 1 because: the higher temperature (34℃ vs 32℃) accelerated the polycondensation and dehydration reaction rate, the sufficient humidity (90% vs 88%) ensured the full swelling and orientation of the polymer chain segments, and the longer curing period (11d vs 10d) made the covalent crosslinked network more dense and complete.

[0071] Example 3: High temperature and high humidity curing conditions (S4-High: 36℃, RH=92%, 12d) Example 3 uses the high-end maintenance conditions of step 4: temperature 36℃ (high-end value), relative humidity 92% (high-end value), and maintenance cycle of 12 days (high-end value).

[0072] Specific operation: Transfer the recombinant precursor S3-H to a constant temperature and humidity curing chamber, set the chamber temperature to 36℃ (the target value of this application is 32℃ to 36℃, taking the high end value), the relative humidity to 92% (the target value of this application is 88% to 92%, taking the high end value), and the curing period to 12 days (the target value of this application is 10d to 12d, taking the high end value), to obtain the pre-cured recycled substrate S4-H.

[0073] Actual results: Free volume shrinkage rate 9.3% (target value of 9% to 11% in this application, meets the requirements), crosslinking network density 4.08 × 10⁻⁶ -4 mol / cm 3 (Target value of this application: 4.0 × 10) -4 mol / cm 3 Up to 4.5×10 -4 mol / cm 3The temperature was 71.5℃ (the target value for this application is 68℃ to 72℃, which meets the requirements). The unconfined compressive strength reached 2.10 MPa (slightly better than Example 2), the internal friction angle φ = 32.6°, and the interfacial cohesion c = 58.2 kPa. Although the high temperature and high humidity long-term curing of Example 3 further improved the mechanical properties, the increase in Tg (71.5℃ vs. 70.5℃ in Example 2) has become relatively gradual, indicating that the crosslinking reaction was nearly complete under the conditions of 36℃, 92%RH, and 12d, and the marginal benefits of further extending the curing time or increasing the temperature are diminishing.

[0074] Example 4: Comprehensive Optimization of Maintenance Parameters (S4-Opt) Example 4 uses comprehensively optimized curing parameters: temperature 33℃, relative humidity 89%, and curing period 11 days. S3-O is cured using the same method to obtain initially cured recycled substrate S4-O. Actual measured results: free volume shrinkage rate 10.2% (meets requirements), crosslinking network density 4.30×10⁻⁶. -4 mol / cm 3 (Meets requirements), Tg = 70.2℃ (Meets requirements), unconfined compressive strength 1.96MPa, internal friction angle 30.5°, interfacial cohesion 53.2kPa. The overall performance is between that of Examples 2 and 3, see Table 4 for details. Figure 1 .

[0075] Table 4 Summary of mechanical property data in step 4

[0076] Step 5: Hydrophobic modification of vapor phase surface and improvement of impermeability Step 5 of this application introduces a vapor-phase surface hydrophobic modification treatment on the regenerated soil matrix obtained in step 4. Hexamethyldisiloxane (HMDSO, molecular formula (C2H5)2Si(CH3)2O) is used as the hydrophobic modifier, and a vapor-phase grafting reaction is carried out in a closed vapor-phase deposition reaction chamber. The siloxane free radicals generated by the decomposition of HMDSO vapor under heating conditions (130–140°C) undergo a dehydration condensation reaction with the residual silanol groups (Si-OH) on the surface of soil particles, forming a dense Si-O-Si hydrophobic network layer. The introduction of this hydrophobic layer can effectively block the hydrolytic erosion channels of liquid water molecules on the internal heavy metal-ligand chelate structure, further strengthening the long-term retention effect of heavy metals from a chemical perspective.

[0077] All four sets of examples underwent step 5, vapor-phase surface hydrophobic modification treatment. The treatment parameters were taken from the high end or the middle of each parameter range (corresponding one-to-one with the curing scheme in step 4): Example 1 corresponds to a treatment temperature of 130℃ (the target value of this application is 130℃ to 140℃, taking the low end value) and a time of 35min (the target value of this application is 35min to 40min, taking the low end value); Example 2 corresponds to a treatment temperature of 135℃ (middle value) and a time of 37.5min (middle value); Example 3 corresponds to a treatment temperature of 140℃ (high end value) and a time of 40min (high end value); Example 4 corresponds to a treatment temperature of 135℃ and a time of 38min.

[0078] Processing procedure: 200g of recycled soil matrix sample is placed in a closed vapor deposition reaction chamber. The chamber is evacuated to a vacuum level of 70Pa (the target value for this application is 60Pa to 80Pa, using the midpoint). HMDSO vapor is then introduced (flow rate 5mL / min), heated to the set temperature, and held for a specified time to complete the vapor-phase grafting reaction. After treatment, the sample is allowed to cool naturally to room temperature, and the product is collected. Contact angle was measured using an OCA20 contact angle meter (dangling drop method, 25℃ deionized water, droplet volume 2μL, 5 points measured on a flat sample surface, average value taken). Capillary water absorption rate was measured using a self-assembled capillary water absorption device (bottom contact with deionized water, recording the capillary water rise height within 1 hour and converting it to rate). Step 6: Dynamic graded compaction and microcrack self-healing. In step 6 of this application, the impermeable recycled soil treated with vapor-phase hydrophobic modification in step 5 is transferred to a dynamic roller compaction device. Gradual compaction of the soil is achieved through the coupling effect of static load pressure (0.5–0.8 MPa) and vertical excitation force (frequency 10 Hz). During compaction, the amphiphilic polymer segments undergo localized microphase separation and rearrangement at particle contact points, forming a dynamic polymer network with self-healing capabilities. When compaction generates micron-scale structural cracks, the polymer segments migrate into the crack region under capillary action on the crack walls and undergo secondary cross-linking reactions (hydrogen bond self-assembly and limited covalent re-cross-linking) between residual unreacted functional groups (-OH, -COOH), automatically filling the crack space and thus achieving the self-healing function of the microcracks.

[0079] The processing parameters in step 6 of the four sets of embodiments correspond one-to-one with the schemes in steps 1 to 5: Embodiment 1 uses a static load of 0.5MPa (the target value of this application is 0.5MPa to 0.8MPa, taking the lower end of the value), an excitation frequency of 10Hz (fixed value), a target compaction degree of 92% (the target value of this application is 92% to 95%, taking the lower end of the value), and aging for 48h (the target value of this application is 48h to 72h, taking the lower end of the value); Embodiment 2 uses a static load of 0.65MPa (intermediate value), a target compaction degree of 93.5% (intermediate value), and aging for 60h (intermediate value); Embodiment 3 uses a static load of 0.8MPa (high end value), a target compaction degree of 95% (high end value), and aging for 72h (high end value); Embodiment 4 uses a static load of 0.65MPa, a target compaction degree of 93.5%, and aging for 60h.

[0080] After compaction, nuclear magnetic resonance imaging (MRI) was used to determine the internal pore distribution and crack self-healing effect of the sample (crack width < 5 μm is considered effective repair); at the same time, the final product was verified by standard direct shear test (to ensure that the internal friction angle and cohesion do not decrease after microcrack self-healing treatment).

[0081] Table 5 shows the final products of the four sets of examples and a set of control samples without any passivation treatment (only subjected to high shear depolymerization but without passivation treatment, vibration shear self-assembly and cross-linking curing) for heavy metal leaching concentration detection using the toxicity characteristic leaching procedure method (TCLP, USEP Method 1311).

[0082]

[0083] As shown in the table, the final products of all four examples meet the heavy metal leaching concentration limits specified in this application: lead (Pb) < 0.08 mg / L (the most stringent limit, met by all four), cadmium (Cd) < 0.004 mg / L (Example 2 is the best, 0.0019 mg / L), hexavalent chromium < 0.10 mg / L, and arsenic < 0.25 mg / L. Example 2 showed the best performance in heavy metal passivation, mainly due to the intermediate passivation parameter combination of pH=6.25 and T=50℃ used in step 2. Under this parameter combination, the chelation stability constant lgK reached the highest of 15.6, resulting in the most stable cyclic chelation structure. The heavy metal ion mobility of all four examples decreased to less than 5% of the initial value, meeting the technical requirement of the present application that the heavy metal ion mobility decrease to less than 5% of the initial value.

[0084] This application's technical solution achieves the synergistic construction of a four-level mechanochemical locking mechanism: covalent bonds, coordination bonds, hydrogen bonds, and intermolecular forces. The covalent cross-linked network (from the polymer condensation and dehydration reaction in step 4) provides rigid molecular network support to the micro-aggregate skeleton, rigidly locking the hierarchical porous three-dimensional skeleton. Coordinate bonds (from the heavy metal-polydentate ligand chelate structure in step 2) provide strong chemical bonding between metals and ligands (bond dissociation energy > 285 kJ / mol, the target value in this application is > 285 kJ / mol). Hydrogen bonds (from the ligand-hydroxyl hydrogen bond bridging in step 2 and the amphiphilic polymer-particle hydrogen bond binding in step 3) provide moderate-strength reversible bonding. Van der Waals forces (from the overlap of fused-ring aromatic π-π electron clouds in step 3 and the intermolecular potential well between particles) provide weak but widespread intermolecular attraction. These four forces work synergistically at different scales, enabling the macroscopic mechanical properties of the regenerated soil system to precisely match the ecological engineering carrying capacity threshold.

[0085] The final product of Example 2 (with the best overall performance) was subjected to dynamic leaching under simulated pH 3.5 acid rain (leaching solution flow rate 0.5 mL / min, leaching time 72 h, equivalent to 10 years of natural rainfall) and coupled with 100 freeze-thaw cycles from -15℃ to 25℃. The test results showed that the unconfined compressive strength attenuation rate was <5% (measured at 4.6%), the internal friction angle measured by the standard direct shear test was maintained at 30.2° (meeting the ≥27° requirement specified in this application), and the interfacial cohesion was maintained at 53.5 kPa (meeting the >48 kPa requirement specified in this application). Meanwhile, the characteristic leaching concentrations of heavy metals are consistently lower than the limits specified in this application (Pb < 0.075 mg / L, Cd < 0.0035 mg / L, Cr(VI) < 0.09 mg / L, As < 0.22 mg / L), the static water contact angle is not less than 112° (measured 114°), the capillary water rise rate is not higher than 1.05 mm / min (measured 1.02 mm / min), and the permeability coefficient is controlled at 3.8 × 10⁻⁶. - 6 cm / s to 4.5×10 -6 Within the range of cm / s (meeting the 3.5×10 specified in this application) -6 cm / s to 5.2×10 -6 (cm / s requirement), fully meeting the dual requirements of long-term mechanical bearing capacity of the matrix, impermeability isolation and in-situ solidification of heavy metals for ecological restoration projects of high and steep slopes.

[0086] Example 2: Mercury intrusion porosimetry pore size distribution of the final product: Micropore size is concentrated in the 10–50 nm range, and mesopore size is concentrated in the 200–500 nm range (median 330 nm; mesopores in this application range 200 nm to 500 nm), exhibiting a typical bimodal distribution. Total porosity is 19.8% (target value of 18.5% to 21.5%, meeting the requirements), and the average equivalent diameter of aggregates is 1.15 mm (target value of 0.8 mm to 1.5 mm, meeting the requirements). Combined Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) characterization results show an intermolecular hydrogen bond bridging density of 4.38 × 10⁻⁶. 2 pcs / m 3 The van der Waals force potential well depth is -19.8 kJ / mol (within the target range of -18 kJ / mol to -22 kJ / mol, meeting the requirements), and the measured average bond dissociation energy of the ligand-metal chelate bond is 296 kJ / mol. The synergistic enhancement effect of these multi-scale intermolecular forces provides a solid physicochemical basis for the long-term mechanical stability and long-term retention of heavy metals in regenerated soils.

[0087] This application precisely disrupts the weak van der Waals agglomeration structure between industrial solid waste particles through high-shear deagglomeration treatment, effectively stripping the surface passivation layer and exposing the active coordination sites of silanol and aluminol within the crystal lattice. This significantly increases the specific surface area and surface active site density of the powder, providing a highly active reaction substrate for subsequent chemical coordination reactions. By introducing a multidentate coordination passivation liquid containing carboxyl and phosphate groups, it drives the formation of thermodynamically stable cyclic chelate structures between heavy metal cations and silanol / aluminum active sites, greatly enhancing the hydrolysis free energy barrier of the heavy metal complex bonds, achieving deep chemical passivation and long-term retention of heavy metals in solid waste. Furthermore, it precisely utilizes directional vibration shearing self-assembly... A hierarchical three-dimensional pore framework with both micropores and mesopores was constructed. This optimized the water retention and aeration properties of the recycled soil and the root penetration channels. At the same time, the binding energy and macroscopic shear strength of the micro-aggregate interface were enhanced through multi-scale intermolecular forces. The hierarchical three-dimensional pore framework was rigidly locked by triggering covalent cross-linking network solidification through constant temperature and humidity curing. The internal friction angle and interfacial cohesion parameters of the particle contact surface were simultaneously controlled to form a multi-level mechanical and chemical locking mechanism of covalent bonds, coordination bonds, hydrogen bonds, and intermolecular forces. Finally, harmless recycled soil from industrial solid waste with low leaching risk, excellent mechanical stability, and long-term ecological service capability was obtained.

Claims

1. A method for preparing harmless recycled soil from industrial solid waste, characterized in that, Includes the following steps: Step 1: High-shear deagglomeration of industrial solid waste is performed to destroy the van der Waals force agglomeration structure between particles and expose the surface silicon-aluminum hydroxyl active sites to obtain activated powder. Step 2: Inject a multidentate coordination passivation solution containing carboxyl and phosphate groups into the activated powder, and react under controlled temperature and pH. Through hydrogen bonding bridging between the ligand and hydroxyl groups and steric hindrance, heavy metal ions are promoted to form a cyclic chelate structure with the active site to obtain primary passivation powder. Step 3: The primary passivated powder is dry-mixed with biochar containing a fused ring aromatic structure and an amphiphilic polymer. A directional vibration shear flow field is applied, and the particles are oriented to self-assemble and densely arranged by utilizing electron cloud overlap, dipole polarization traction and residual van der Waals force vector superposition to construct a hierarchical porous three-dimensional skeleton and obtain a recombinant precursor. Step 4: The recombinant precursor is cured at constant temperature and humidity to trigger polymer chain segment condensation dehydration and covalent cross-linking to solidify the skeleton. Simultaneously, the internal friction angle and interfacial cohesion of the particle contact surface are controlled to make the shear strength of the system match the ecological carrying capacity threshold, thus obtaining recycled soil with low leaching risk and stable structure.

2. The method for preparing harmless recycled soil from industrial solid waste as described in claim 1, characterized in that, In step 1, the specific process parameters for high-shear depolymerization of industrial solid waste are as follows: The pretreated metallurgical water-quenched slag and pulverized coal ash are mixed at a mass ratio of 3:1 to 4:1 and then fed into a high-shear disperser with a rotor linear velocity of 28 m / s to 32 m / s. A continuous shearing process was applied for 18 to 22 minutes, with a negative pressure of 0.02 to 0.04 MPa maintained inside the shearing chamber to simultaneously remove free bound water. After the depolymerization treatment, the median particle size (D50) of the resulting activated powder was controlled between 8 and 12 μm, and the specific surface area was increased to 2.0 m². 2 / g to 2.5m 2 / g, the total concentration of exposed silanol and aluminum hydroxyl groups on the surface reaches 1.5 mmol / g to 2.0 mmol / g.

3. The method for preparing harmless recycled soil from industrial solid waste as described in claim 2, characterized in that, In step 2, the multidentate coordination passivation solution injected into the activated powder is prepared by dissolving citric acid, phytic acid and potassium dihydrogen phosphate in deionized water at a mass ratio of 2:1:1.

5. The concentration of free carboxyl groups in the passivation solution is set to 0.9 mol / L to 1.1 mol / L, and the concentration of free phosphate anions is set to 0.7 mol / L to 0.9 mol / L. The activated powder and passivation solution are placed in a corrosion-resistant reactor at a solid-liquid mass ratio of 1:1.2 to 1:1.

5. The reaction is carried out under temperature and acid control conditions of 48°C to 52°C and pH value of 6.0 to 6.5 with mechanical stirring for 50 to 55 minutes. During the reaction, the hydrogen bond bridging between the ortho-oxygen atom of the polydentate ligand and the surface hydroxyl group and the steric hindrance effect of the macromolecule are used to promote the formation of a five- or six-membered cyclic chelate structure with a coordination bond length of 0.19 nm to 0.21 nm between the heavy metal cation and the active site of the silicon-aluminum. The chelation thermodynamic stability constant lgK≥13.5, after the reaction is completed, the primary passivated powder is obtained by solid-liquid separation and low-temperature vacuum drying.

4. The method for preparing harmless recycled soil from industrial solid waste as described in claim 3, characterized in that, In step 3, the specific mass ratio of the primary passivation powder to the biochar containing a fused-ring aromatic structure and the amphiphilic polymer is as follows: The primary passivation powder comprises 100 parts, the biochar comprises 18 to 22 parts, and the amphiphilic polymer comprises 4 to 6 parts; the biochar is obtained by pyrolysis and carbonization of rice husks, agricultural and forestry waste, at 650°C under a nitrogen inert atmosphere, and has a graphite microcrystal spacing of 0.345 nm and a specific surface area of ​​300 m². 2 / g to 350m 2 / g, with surface oxygen-containing functional group content ranging from 2.8 mmol / g to 3.2 mmol / g; The amphiphilic polymer is a graft copolymer of sodium carboxymethyl cellulose and polyvinyl alcohol, with a number average molecular weight of 18,000 Da to 22,000 Da and a hydrophilic-lipophilic balance (HLB) of 13.0 to 13.

5. The dry mixing process is carried out in a planetary mixer at a revolution speed of 30 rpm and a rotation speed of 150 rpm for 15 to 20 minutes, so that the components are uniformly dispersed at the molecular scale and the interfaces are pre-wetted to obtain a dry-mixed homogeneous intermediate.

5. The method for preparing harmless recycled soil from industrial solid waste as described in claim 4, characterized in that, In step 3, the specific dynamic parameters for applying a directional vibration shear flow field to the dry-mixed homogeneous intermediate for reorganization are as follows: The material is placed in a three-dimensional vibration shearing molding machine, with the vibration frequency set to 45Hz to 55Hz, the mechanical amplitude to 1.5mm to 1.7mm, and the shear rate gradient to 90s. -1 up to 110s -1 The flow field lasts for 25 to 30 minutes. Under the coupling effect of shear stress and inertial force in the flow field, the particle group undergoes directional translational and rotational coupled motion along the principal stress direction. The normal compressive stress at the particle contact point reaches 0.9 MPa to 1.1 MPa, which shortens the overlap distance of π-π electron clouds between the fused ring aromatic structures of biochar to within 0.34 nm. The intermolecular dipole polarization traction force and the residual van der Waals force vector superposition form an intermolecular interaction potential well with a depth of -16 kJ / mol to -19 kJ / mol, inducing the particles to directional self-assemble and densely arrange themselves along the shear streamline direction, constructing a hierarchical three-dimensional framework with micropores of 15 nm to 45 nm and mesopores of 250 nm to 450 nm, thus obtaining the recombinant precursor.

6. The method for preparing harmless recycled soil from industrial solid waste as described in claim 5, characterized in that, In step 4, the environmental parameters for transferring the recombinant precursor to a constant temperature and humidity curing chamber for crosslinking and maturation are set as follows: The internal temperature was maintained at 32℃ to 36℃, and the relative humidity was controlled at 88% to 92%, with a curing cycle of 10 to 12 days. During the curing period, residual free water molecules in the system underwent a stepwise polycondensation and dehydration reaction with the terminal hydroxyl groups of the amphiphilic polymer, triggering the solidification of the covalent cross-linked network between polymer chain segments. The free volume shrinkage rate of the system during the reaction was strictly controlled at 9% to 11%, and the cross-linked network density reached 4.0 × 10⁻⁶, as determined by the Flory-Rehner swelling equilibrium method. -4 mol / cm 3 Up to 4.5×10 -4 mol / cm 3 The glass transition temperature (Tg) of the polymer chain segments is increased to 68°C to 72°C, which enables the micro-aggregate skeleton to obtain rigid molecular network support, resulting in a pre-cured regenerated substrate.

7. The method for preparing harmless recycled soil from industrial solid waste as described in claim 6, characterized in that, In step 4, the specific quantitative indicators for simultaneously controlling the internal friction angle and interfacial cohesion of the particle contact surface to match the shear strength of the system with the ecological carrying capacity threshold are as follows: The initial cured recycled substrate after curing has a strength of not less than 1.8 MPa in the unconfined compressive strength test, the internal friction angle measured by the standard direct shear test is between 29° and 33°, and the interfacial cohesion of the particle contact surface is between 50 kPa and 60 kPa. The regenerated soil was tested using a toxicity characteristic leaching procedure, and the leaching concentrations of lead, cadmium, hexavalent chromium, and arsenic were lower than 0.08 mg / L, 0.004 mg / L, 0.10 mg / L, and 0.25 mg / L, respectively. The migration rate of heavy metal ions decreased to less than 5% of the initial value, resulting in a regenerated soil matrix with low leaching risk and stable macroscopic structure.

8. The method for preparing harmless recycled soil from industrial solid waste as described in claim 7, characterized in that, After obtaining the regenerated soil matrix in step 4, the method further includes a step of performing vapor-phase surface hydrophobic modification treatment on the regenerated soil matrix: The regenerated soil matrix was placed in a closed vapor-phase deposition reaction chamber, and after being evacuated to a vacuum degree of 60 Pa to 80 Pa, hexamethyldisiloxane vapor was introduced. The vapor-phase grafting reaction was carried out at a heating temperature of 130°C to 140°C for 35 min to 40 min, which caused the residual silanol groups on the surface of the soil particles to undergo a dehydration condensation reaction with the small molecules of siloxane, forming a dense Si-O-Si hydrophobic network layer. After the modification treatment, the static water contact angle on the particle surface increased to 115° to 125°, and the capillary water rise rate decreased to 0.9 mm / min to 1.1 mm / min, effectively blocking the hydrolytic erosion of the internal chelate structure by liquid water molecules, resulting in impermeable regenerated soil.

9. The method for preparing harmless recycled soil from industrial solid waste as described in claim 8, characterized in that, After obtaining the impermeable recycled soil in the above steps, the method further includes a step of dynamically graded compaction and micro-crack self-healing treatment of the impermeable recycled soil: Impermeable recycled soil is transported to a dynamic roller pressing device, and a static load pressure of 0.5MPa to 0.8MPa is applied in conjunction with a vertical excitation force with a frequency of 10Hz for gradient compaction. After the compaction degree reaches 92% to 95%, it is left to stand and age for 48h to 72h. By utilizing the microphase separation characteristics of amphiphilic polymer segments and the secondary cross-linking effect of residual unreacted functional groups, the micron-level structural cracks generated during the compaction process are automatically filled, so that the macroscopic porosity of the system is finally stabilized in the range of 18% to 22%, while maintaining an internal friction angle of not less than 28° and a heavy metal leaching concentration fluctuation of less than 3%. Finally, a harmless recycled soil product from industrial solid waste is obtained that meets the dual mechanical and hydrological requirements of ecological restoration engineering for steep slopes.

10. A type of harmless recycled soil from industrial solid waste prepared by the method according to any one of claims 1 to 9, characterized in that, The microscopic interface of the regenerated soil particles is constructed by a cyclic chelate network of silicoaluminohydroxy-polydentate ligands and an overlapping region of π-π electron clouds of fused-ring aromatic structures, with an intermolecular hydrogen bond bridging density of not less than 4.2 × 10⁻⁶. 20 pcs / m 3 The van der Waals force potential well depth remained in the range of -18 kJ / mol to -22 kJ / mol, and the average bond dissociation energy of the ligand-metal chelate bond was higher than 285 kJ / mol. The macroscopic phase exhibited a hierarchical pore topology network with a bimodal distribution of micropores (10 nm to 50 nm) and mesopores (200 nm to 500 nm), with the total porosity remaining stable at 18.5% to 21.5%, and the average equivalent diameter of the aggregates ranging from 0.8 mm to 1.5 mm. After undergoing 100 cycles of simulated pH 3.5 acid rain dynamic leaching and freeze-thaw cycles from -15°C to 25°C, the regenerated soil exhibited an unconfined compressive strength attenuation rate of less than 8%, an internal friction angle measured by standard direct shear tests maintained between 27° and 31°, interfacial cohesion at particle contact surfaces remained between 48 kPa and 58 kPa, and the characteristic leaching concentrations of lead, cadmium, hexavalent chromium, and arsenic remained consistently below 0.075 mg / L, 0.0035 mg / L, 0.09 mg / L, and 0.22 mg / L, respectively. The surface static water contact angle was not less than 112°, the capillary rise rate was not higher than 1.05 mm / min, and the permeability coefficient was controlled at 3.5 × 10⁻⁶. -6 cm / s to 5.2×10 -6 cm / s, meeting the dual requirements of long-term mechanical bearing capacity, impermeability isolation, and in-situ solidification of heavy metals for ecological restoration projects on steep slopes.

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