Multi-source tailing solid waste-based road base material and preparation method thereof

Abstract

The invention discloses a multi-source tailing solid waste-based road base material and a preparation method thereof, and belongs to the technical field of road engineering materials. The material is prepared by taking industrial solid wastes such as gold tailings and iron ore tailings as main raw materials and adding an alkaline activator, a gelling matrix material, an additive, modified montmorillonite, an anti-cracking material and the like. The modified montmorillonite is modified by adopting a composite pillared agent and a chelating agent, through ion exchange and chelation, the curing effect on heavy metal ions is remarkably improved, and the leaching toxicity is reduced. Meanwhile, the material has good freeze-thaw stability, and the influence of frost heaving stress on the structure is effectively reduced. Compared with the prior art, efficient utilization of industrial solid waste is achieved, the production cost is reduced, dependence on natural materials is reduced, and remarkable environmental protection and economic benefits are achieved.

Description

Technical Field

[0001] This invention relates to the field of road engineering materials technology, and in particular to a multi-source tailings solid waste-based road base material and its preparation method. Background Technology

[0002] With rapid industrialization and urbanization, the massive generation of industrial solid waste such as tailings has become an urgent environmental problem. Tailings contain various heavy metal ions, such as copper, lead, zinc, and cadmium. These heavy metal ions have high mobility and biotoxicity in the natural environment, and if left untreated, they will cause serious pollution to soil, water bodies, and ecosystems. Traditional tailings treatment methods mainly focus on landfill and stockpiling, but these methods not only consume large amounts of land resources but also pose a risk of heavy metal leakage. In recent years, researchers have begun to explore new ways to utilize tailings resources, especially in the field of road engineering.

[0003] In the preparation of road base materials, traditional inorganic binders (such as cement and lime) can provide a certain mechanical strength, but they are insufficient in terms of heavy metal solidification and durability. For example, ordinary cement-based materials are prone to structural damage under freeze-thaw cycles, leading to a decrease in strength, and their solidification effect on heavy metal ions in tailings is limited. In addition, existing tailings-based road materials often require the addition of large amounts of cementitious materials during the preparation process, which not only increases costs but may also cause secondary pollution to the environment.

[0004] In recent years, some studies have attempted to improve the performance of tailings-based road base materials by adding modified materials. For example, Chinese invention patent application CN117819887A discloses an inorganic binder-stabilized gold tailings mixture. By adding matrix materials such as industrial slag powder, fly ash, and silica fume, as well as crack-resistant materials such as steel slag powder and fibers extracted from waste wind turbine blades, the mechanical properties and water stability of the mixture are improved. However, this method still has shortcomings in heavy metal solidification and limited improvement in freeze-thaw cycle durability. Another patent application, CN113003991A, achieves the cementation of tailings materials and solidification of heavy metal ions by adding specific pollutant solidifying agents (such as fly ash and lime) and active activators. However, in practical applications, its preparation process is complex and its adaptability to different types of tailings is limited.

[0005] In summary, existing technologies for preparing tailings-based road base materials have the following shortcomings: first, the solidification effect on heavy metals is limited, making it difficult to meet stringent environmental protection requirements; second, insufficient freeze-thaw stability affects the long-term service life of the road base material; and third, the preparation process is complex and costly, limiting its large-scale application. Therefore, developing a multi-source tailings solid waste-based road base material and its preparation method that can effectively solidify heavy metals, improve freeze-thaw stability, and reduce costs has significant practical implications and broad application prospects. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention aims to provide a multi-source tailings solid waste-based road base material and its preparation method.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] A method for preparing a multi-source tailings solid waste-based road base material includes the following raw materials: 120-180 parts of gold tailings, 20-30 parts of alkaline activator, 20-30 parts of iron ore, 30-45 parts of cementitious matrix material, 5-10 parts of admixture, 1-3 parts of modified montmorillonite, 10-15 parts of crack-resistant material, and 40-80 parts of water.

[0009] The preparation method of the modified montmorillonite includes the following steps:

[0010] S1. While stirring the composite pillaring agent, add sodium hydroxide aqueous solution dropwise to adjust the pH, continue stirring and age at a constant temperature to obtain an ionic solution; add the ionic solution to the montmorillonite aqueous suspension, stir and age, wash with water, freeze dry and sieve to obtain pretreated montmorillonite.

[0011] S2. Add the pretreated montmorillonite to the chelating agent aqueous solution, adjust the pH with hydrochloric acid, shake at room temperature, centrifuge, wash with water, freeze dry, grind and sieve to obtain modified montmorillonite.

[0012] The preparation method of the multi-source tailings solid waste-based road base material is as follows:

[0013] Step 1: The gold tailings are first washed with water, and the remaining lumpy tailings are ground into powder using a cake mill; finally, they are dried to control the moisture content to <5%-10% to obtain homogeneous tailings raw materials.

[0014] Step 2: Mix the alkaline activator with the homogeneous tailings raw material and let it stand for 10-20 minutes; mix the iron ore, cementitious matrix material, admixture, modified montmorillonite, and water into a slurry and stir for 5-10 minutes; add the crack-resistant material and stir lightly for 1-3 minutes until uniform; determine the optimum moisture content according to the compaction test of the "Standard for Geotechnical Testing Methods" (GB / T 50123-2019); add water and stir for 1-5 minutes to obtain the road base material.

[0015] The alkaline activator is at least one of water glass and red mud.

[0016] The cementitious matrix material is at least one of blast furnace slag powder, fly ash, silica fume, and lime.

[0017] The additive is at least one of desulfurized gypsum and ammonium dihydrogen phosphate.

[0018] The crack-resistant material is at least one of steel slag powder and basalt fiber.

[0019] Preferably, the modified montmorillonite is prepared by the following method, in parts by weight:

[0020] S1. Take 5-15 parts of the composite pillaring agent, stir at 100-300 rpm at 50-70℃, add 0.05-0.2 mol / L sodium hydroxide aqueous solution dropwise until pH=6-7, continue stirring for 1-3 h, age at 60-70℃ for 10-30 h to obtain an ionic solution; add the ionic solution to 200-300 parts of 0.5-2 wt% montmorillonite aqueous suspension, stir at 80-90℃ for 1-3 h, age at 60-70℃ for 10-30 h, wash with water, freeze dry and pass through a 150-400 mesh sieve to obtain pretreated montmorillonite;

[0021] S2. Take 1-3 parts of pretreated montmorillonite and add them to 400-600 parts of 30-80 mg / L chelating agent aqueous solution. Add 0.05-0.2 mol / L hydrochloric acid to adjust the pH to 4-6. Shake at 100-400 rpm for 5-20 h at room temperature, centrifuge at 8000-15000 rpm for 3-15 min, wash with water, freeze dry, grind and pass through a 100-400 mesh sieve to obtain modified montmorillonite.

[0022] The composite pillaring agent is a mixture of 0.1-0.3 mol / L chromium trichloride aqueous solution and 0.1-0.3 mol / L aluminum chloride aqueous solution in a mass ratio of 1:10-20, or a 0.1-0.3 mol / L zirconium oxychloride aqueous solution.

[0023] The chelating agent is at least one of glutathione and L-penicillamine.

[0024] The roles of each substance in the preparation of modified montmorillonite in this invention are as follows:

[0025] The composite pillaring agent (chromium trichloride and aluminum chloride) generates large-sized polynuclear hydroxy cations at pH 6.5, which are inserted into the interlayer of montmorillonite through ion exchange, thereby expanding the interlayer spacing and providing greater adsorption space and structural stability.

[0026] Sodium hydroxide aqueous solution is used as a hydrolysis pH adjuster to control the formation of ideal polynuclear cations in the composite pillaring agent at pH=6.5 (avoiding the formation of precipitates or ineffective monomers) and optimize the pillaring effect.

[0027] Montmorillonite (substrate) serves as a layered silicate carrier. Its interlayer negative charge and silanol groups adsorb pillaring agent cations through ion exchange, forming stable oxide pillars and enhancing thermal stability.

[0028] Glutathione forms a tridentate chelate ring with its γ-glutamyl, cysteyl, and glycyl groups, which efficiently captures heavy metal ions while reducing strength loss during freeze-thaw cycles.

[0029] The modified montmorillonite of this invention achieves deep solidification (chelation) and improved durability (hydrophobic and frost-resistant) of heavy metals through the synergistic design of pillar-supported layer expansion and chelated functional group grafting, providing a core environmentally friendly reinforcing phase for solid waste-based road materials.

[0030] Compared with existing technologies, it has the following advantages:

[0031] 1) By using modified montmorillonite, this invention can significantly reduce the leaching of heavy metal ions, which is far lower than the heavy metal leaching level in the prior art. This efficient heavy metal solidification ability effectively reduces the risk of environmental pollution.

[0032] 2) This invention significantly improves the freeze-thaw stability of road base materials, blocks capillary migration of moisture, reduces frost heave stress, and inhibits structural collapse during freeze-thaw cycles, effectively improving the durability of road base materials.

[0033] 3) This invention utilizes multi-source tailings solid waste (such as gold tailings and iron ore tailings) as the main raw material, achieving efficient utilization of industrial solid waste, reducing dependence on natural materials, and lowering production costs. Simultaneously, by optimizing material formulation and preparation processes, the performance of road base materials is further improved, giving them significant advantages in both environmental protection and economic efficiency. Detailed Implementation

[0034] Main source of materials:

[0035] The gold tailings originate from a gold tailings dam near the Zhaoyuan Linglong exit of the S19 Longqing Expressway in Zhaoyuan City, Shandong Province. The particle size distribution is as follows: >147μm 0.20%; 147-74μm 11.28%; 74-55μm 17.54%; 55-43μm 7.22%; 43-38μm 9.96%; 38-28μm 7.21%; 28-21μm 7.90%; 21-12μm 11.23%; 12-5μm 10.70%; 5-0μm 16.76%.

[0036] The iron ore tailings originate from the dry discharge tailings of the iron ore beneficiation process at Shengde Rixin Mining Co., Ltd. Their main components are as follows: SiO2 41.11%, Fe2O3 10.8%, Al2O3 8.19%, CaO 13.99%, MgO 16.7%, SO3 0.46%, K2O 0.72%, Na2O 0.29%; particle size distribution is as follows: >150μm 9.51%; 150-100μm 6.98%; 100-75μm 5.18%; 75-45μm 8.76%; <45μm 69.57%.

[0037] Water glass, product number: TXHG-005, Shandong Tianxiang Chemical Co., Ltd.

[0038] Red mud, item number: h858558, specification: 325 mesh, Lingshou Yixin Mineral Products Processing Plant.

[0039] Blast furnace slag powder, item number: KF-K8U6, grade: first grade, produced by Lingshou County Zhanteng Mineral Products Processing Plant.

[0040] Fly ash, specification: 325 mesh, item number: ZM0033, Lingshou County Zemin Mineral Products Processing Plant.

[0041] Silica fume, item number: bc88, produced by Lingshou County Bocai Mineral Products Processing Plant.

[0042] Desulfurized gypsum, item number: 033, Hebei Hengyue Mineral Products Co., Ltd.

[0043] Steel slag powder, specifications: 80-120 mesh, item number: 06, Shijiazhuang Xunluo New Material Technology Co., Ltd.

[0044] Basalt fiber, fiber length 18mm, Hebei Jinghang Mineral Products Co., Ltd.

[0045] Montmorillonite, item number: 0037, product specifications: 200-1250 mesh, Shanghai Wanzhao Fine Chemical Co., Ltd.

[0046] All other raw materials used in the embodiments and comparative examples of this invention are commercially available products.

[0047] Example 1

[0048] A method for preparing a multi-source tailings solid waste-based road base material is as follows, in parts by weight:

[0049] Step 1: First, wash 150 portions of gold tailings with water. Grind the remaining lumpy tailings into powder using a cake mill. Finally, dry the powder to control the moisture content to <5% to obtain homogeneous tailings raw material.

[0050] Step 2: Mix 10 parts water glass and 15 parts red mud with homogeneous tailings raw materials and let stand for 15 minutes; mix 25 parts iron ore, 16 parts blast furnace slag powder, 13 parts fly ash, 4 parts silica fume, 5 parts lime, 2 parts desulfurized gypsum, 5 parts ammonium dihydrogen phosphate, 2 parts modified montmorillonite, and 60 parts water to form a slurry and stir for 8 minutes; add 8 parts steel slag powder and 4 parts basalt fiber, stir lightly for 2 minutes until uniform, determine the optimum moisture content according to the compaction test of the "Standard for Geotechnical Testing Methods" (GB / T 50123-2019), add water and stir for 2 minutes to obtain the road base material.

[0051] The modified montmorillonite is prepared as follows, in parts by weight:

[0052] S1. Take 10 parts of composite pillaring agent, which is a mixture of 0.2 mol / L chromium trichloride aqueous solution and 0.2 mol / L aluminum chloride aqueous solution in a mass ratio of 1:15. Stir at 200 rpm at 60℃, add 0.1 mol / L sodium hydroxide aqueous solution dropwise until pH = 6.5, continue stirring for 2 h, and age at 65℃ for 24 h to obtain an ionic solution. Add the ionic solution to 250 parts of 1 wt% montmorillonite aqueous suspension, stir at 85℃ for 2 h, age at 65℃ for 24 h, wash with water, freeze dry, and pass through a 200-mesh sieve to obtain pretreated montmorillonite.

[0053] S2. Take 2 parts of pretreated montmorillonite and add them to 500 parts of 50 mg / L glutathione aqueous solution. Add 0.1 mol / L hydrochloric acid to adjust the pH to 5.0. Shake at 300 rpm for 12 h at room temperature, centrifuge at 12000 rpm for 10 min, wash with water, freeze dry, grind and pass through a 200 mesh sieve to obtain modified montmorillonite.

[0054] Example 2

[0055] The preparation method of a multi-source tailings solid waste-based road base material is basically the same as that in Example 1, except that the preparation method of the modified montmorillonite is different.

[0056] The modified montmorillonite is prepared as follows, in parts by weight:

[0057] S1. Take 10 parts of composite pillaring agent, wherein the composite pillaring agent is a 0.2 mol / L zirconium oxychloride aqueous solution, stir at 200 rpm at 60℃, add 0.1 mol / L sodium hydroxide aqueous solution dropwise until pH = 6.5, continue stirring for 2 h, and age at 65℃ for 24 h to obtain an ionic solution; add the ionic solution to 250 parts of 1 wt% montmorillonite aqueous suspension, stir at 85℃ for 2 h, age at 65℃ for 24 h, wash with water, freeze dry and pass through a 200 mesh sieve to obtain pretreated montmorillonite;

[0058] S2. Take 2 parts of pretreated montmorillonite and add them to 500 parts of 50 mg / L glutathione aqueous solution. Add 0.1 mol / L hydrochloric acid to adjust the pH to 5.0. Shake at 300 rpm for 12 h at room temperature, centrifuge at 12000 rpm for 10 min, wash with water, freeze dry, grind and pass through a 200 mesh sieve to obtain modified montmorillonite.

[0059] Example 3

[0060] The preparation method of a multi-source tailings solid waste-based road base material is basically the same as that in Example 1, except that the preparation method of the modified montmorillonite is different.

[0061] The modified montmorillonite is prepared as follows, in parts by weight:

[0062] S1. Take 10 parts of composite pillaring agent, which is a mixture of 0.2 mol / L chromium trichloride aqueous solution and 0.2 mol / L aluminum chloride aqueous solution in a mass ratio of 1:15. Stir at 200 rpm at 60℃, add 0.1 mol / L sodium hydroxide aqueous solution dropwise until pH = 6.5, continue stirring for 2 h, and age at 65℃ for 24 h to obtain an ionic solution. Add the ionic solution to 250 parts of 1 wt% montmorillonite aqueous suspension, stir at 85℃ for 2 h, age at 65℃ for 24 h, wash with water, freeze dry, and pass through a 200-mesh sieve to obtain pretreated montmorillonite.

[0063] S2. Take 2 parts of pretreated montmorillonite and add them to 500 parts of 50 mg / L L-penicillamine aqueous solution. Add 0.1 mol / L hydrochloric acid to adjust the pH to 5.0. Shake at 300 rpm for 12 h at room temperature, centrifuge at 12000 rpm for 10 min, wash with water, freeze dry, grind and pass through a 200 mesh sieve to obtain modified montmorillonite.

[0064] Comparative Example 1

[0065] The preparation method of a multi-source tailings solid waste-based road base material is basically the same as that in Example 1, except that the preparation method of the modified montmorillonite is different.

[0066] The modified montmorillonite is prepared as follows, in parts by weight:

[0067] S1. Take 10 parts of composite pillaring agent, which is a mixture of 0.2 mol / L ferric chloride aqueous solution and 0.2 mol / L aluminum chloride aqueous solution in a mass ratio of 1:9. Stir at 200 rpm at 60℃, add 0.1 mol / L sodium hydroxide aqueous solution dropwise until pH = 6.5, continue stirring for 2 h, and age at 65℃ for 24 h to obtain an ionic solution. Add the ionic solution to 250 parts of 1 wt% montmorillonite aqueous suspension, stir at 85℃ for 2 h, age at 65℃ for 24 h, wash with water, freeze dry, and pass through a 200-mesh sieve to obtain pretreated montmorillonite.

[0068] S2. Take 2 parts of pretreated montmorillonite and add them to 500 parts of 50 mg / L glutathione aqueous solution. Add 0.1 mol / L hydrochloric acid to adjust the pH to 5.0. Shake at 300 rpm for 12 h at room temperature, centrifuge at 12000 rpm for 10 min, wash with water, freeze dry, grind and pass through a 200 mesh sieve to obtain modified montmorillonite.

[0069] Comparative Example 2

[0070] The preparation method of a multi-source tailings solid waste-based road base material is basically the same as that in Example 1, except that the preparation method of the modified montmorillonite is different.

[0071] The modified montmorillonite is prepared as follows, in parts by weight:

[0072] S1. Take 10 parts of composite pillaring agent, which is a mixture of 0.2 mol / L chromium trichloride aqueous solution and 0.2 mol / L aluminum chloride aqueous solution in a mass ratio of 1:15. Stir at 200 rpm at 60℃, add 0.1 mol / L sodium hydroxide aqueous solution dropwise until pH = 6.5, continue stirring for 2 h, and age at 65℃ for 24 h to obtain an ionic solution. Add the ionic solution to 250 parts of 1 wt% montmorillonite aqueous suspension, stir at 85℃ for 2 h, age at 65℃ for 24 h, wash with water, freeze dry, and pass through a 200-mesh sieve to obtain pretreated montmorillonite.

[0073] S2. Take 2 parts of pretreated montmorillonite and add them to 500 parts of 50 mg / L cysteine ​​aqueous solution. Add 0.1 mol / L hydrochloric acid to adjust the pH to 5.0. Shake at 300 rpm for 12 h at room temperature, centrifuge at 12000 rpm for 10 min, wash with water, freeze dry, grind and pass through a 200 mesh sieve to obtain modified montmorillonite.

[0074] Comparative Example 3

[0075] The preparation method of a multi-source tailings solid waste-based road base material is basically the same as that in Example 1, except that the modified montmorillonite is replaced with an equal amount of montmorillonite.

[0076] Comparative Example 4

[0077] The preparation method of a multi-source tailings solid waste-based road base material is basically the same as that in Example 1, except that the modified montmorillonite is not added.

[0078] Test Example 1

[0079] Leaching toxicity test:

[0080] In the leaching toxicity test, the road base materials prepared in the embodiments and comparative examples of this invention were prepared in test cylinders according to the indoor test methods in the "Specifications for Testing Geotechnical Engineering for Highways" (JTG-E40-2007), based on the compaction requirements for subgrade construction. For the heavy metal leaching toxicity test, the solid waste toxicity test methods specified in the "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB5085.3-2007) were followed. Regarding elemental determination, mercury was determined using inductively coupled plasma mass spectrometry; copper, lead, zinc, and cadmium were determined using inductively coupled plasma atomic emission spectrometry; and cyanide was determined using ion chromatography. The relevant test results are summarized in Table 1.

[0081] Table 1

[0082]

[0083] Test Example 2

[0084] Freeze-thaw strength test:

[0085] The road base materials prepared in the embodiments and comparative examples of the present invention were statically pressed into cylindrical specimens with a compaction degree of 98%, cured to the corresponding age, and tested for strength loss rate after 50 freeze-thaw cycles in accordance with the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (JTG E51-2009). The test results are shown in Table 2.

[0086] Table 2

[0087]

[0088]

[0089] In this invention, Example 1 utilizes a Cr / Al composite pillaring agent. Large-sized polynuclear hydroxy cations, formed by chromium trichloride and aluminum chloride at pH 6.5, are inserted into the interlayer of montmorillonite, significantly increasing the interlayer spacing compared to Zr-based pillaring agents and the Fe / Al system. This expanded layer structure exposes more silanol groups and adsorption sites, which combine with the -SH / -COOH bifunctional groups of glutathione to form a multidentate chelate network, efficiently capturing heavy metal ions and reducing leaching toxicity. Furthermore, the hydrophobicity of the Cr2O3 pillars blocks capillary migration of water, reducing frost heave stress, while Cr...3+ Its thermal stability inhibits structural collapse during freeze-thaw cycles, reducing the strength loss rate, which is superior to hydrophilic Fe / Al pillars and Zr-based systems.

[0090] The synergistic mechanism of glutathione mainly stems from its unique molecular structure and the synergistic effect of its functional groups. Firstly, the γ-glutamyl, cysteyl, and glycyl groups of glutathione form a tridentate chelate ring, whose binding energy for heavy metal ions is significantly higher than that of the single-SH groups of L-penicillamine and cysteine. Data verification also shows that the leaching amount of heavy metal ions in Example 1 is lower than that in other comparative groups. Secondly, the flexible long chain of glutathione can intercalate between montmorillonite layers, forming "molecular bridges" to enhance interfacial bonding, while the rigid structure of L-penicillamine and the small molecule characteristics of cysteine ​​result in low intercalation rates and uneven dispersion, respectively. In summary, glutathione achieves enhanced deep solidification and freeze-thaw cycling of heavy metals through the synergistic effect of multidentate chelation and flexible intercalation.

[0091] The above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a multi-source tailings solid waste-based road base material, characterized in that, The raw materials include: 120-180 parts of gold tailings, 20-30 parts of alkaline activator, 20-30 parts of iron ore, 30-45 parts of cementitious matrix material, 5-10 parts of additives, 1-3 parts of modified montmorillonite, 10-15 parts of crack-resistant material, and 40-80 parts of water. The preparation method of the modified montmorillonite includes the following steps: S1. While stirring the composite pillaring agent, add sodium hydroxide aqueous solution dropwise to adjust the pH, continue stirring and age at a constant temperature to obtain an ionic solution; add the ionic solution to the montmorillonite aqueous suspension, stir and age, wash with water, freeze dry and sieve to obtain pretreated montmorillonite. S2. Add the pretreated montmorillonite to the chelating agent aqueous solution, adjust the pH with hydrochloric acid, shake at room temperature, centrifuge, wash with water, freeze dry, grind and sieve to obtain modified montmorillonite.

2. The method for preparing multi-source tailings solid waste-based road base material as described in claim 1, characterized in that, The preparation method is as follows: Step 1: The gold tailings are first washed with water, and the remaining lumpy tailings are ground into powder using a cake mill; finally, they are dried to control the moisture content to <5%-10% to obtain homogeneous tailings raw materials. Step 2: Mix the alkaline activator with the homogeneous tailings raw material and let it stand for 10-20 minutes; mix the iron ore, cementitious matrix material, admixture, modified montmorillonite, and water into a slurry and stir for 5-10 minutes; add the crack-resistant material and stir lightly for 1-3 minutes until uniform; determine the optimum moisture content according to the compaction test of the "Standard for Geotechnical Testing Methods" (GB / T 50123-2019); add water and stir for 1-5 minutes to obtain the road base material.

3. The method for preparing multi-source tailings solid waste-based road base material as described in claim 1 or 2, characterized in that, The alkaline activator is at least one of water glass and red mud.

4. The method for preparing multi-source tailings solid waste-based road base material as described in claim 1 or 2, characterized in that, The cementitious matrix material is at least one of blast furnace slag powder, fly ash, silica fume, and lime.

5. The method for preparing multi-source tailings solid waste-based road base material as described in claim 1 or 2, characterized in that, The additive is at least one of desulfurized gypsum and ammonium dihydrogen phosphate.

6. The method for preparing multi-source tailings solid waste-based road base material as described in claim 1 or 2, characterized in that, The crack-resistant material is at least one of steel slag powder and basalt fiber.

7. The method for preparing multi-source tailings solid waste-based road base material as described in claim 1 or 2, characterized in that, The modified montmorillonite is prepared as follows, in parts by weight: S1. Take 5-15 parts of composite pillaring agent, stir at 100-300 rpm at 50-70℃, add 0.05-0.2 mol / L sodium hydroxide aqueous solution dropwise until pH=6-7, continue stirring for 1-3 h, and age at 60-70℃ for 10-30 h to obtain ionic solution; Add the ionic solution to 200-300 parts of 0.5-2wt% montmorillonite aqueous suspension, stir at 80-90℃ for 1-3 hours, age at 60-70℃ for 10-30 hours, wash with water, freeze dry, and pass through a 150-400 mesh sieve to obtain pretreated montmorillonite. S2. Take 1-3 parts of pretreated montmorillonite and add them to 400-600 parts of 30-80 mg / L chelating agent aqueous solution. Add 0.05-0.2 mol / L hydrochloric acid to adjust the pH to 4-6. Shake at 100-400 rpm for 5-20 h at room temperature, centrifuge at 8000-15000 rpm for 3-15 min, wash with water, freeze dry, grind and pass through a 100-400 mesh sieve to obtain modified montmorillonite.

8. The method for preparing multi-source tailings solid waste-based road base material as described in claim 7, characterized in that, The composite pillaring agent is a mixture of 0.1-0.3 mol / L chromium trichloride aqueous solution and 0.1-0.3 mol / L aluminum chloride aqueous solution in a mass ratio of 1:10-20, or a 0.1-0.3 mol / L zirconium oxychloride aqueous solution.

9. The method for preparing multi-source tailings solid waste-based road base material as described in claim 7, characterized in that, The chelating agent is at least one of glutathione and L-penicillamine.

10. A multi-source tailings solid waste-based road base material, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.

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