Industrial lithium slag solid waste-based foam light-weight mixed soil and preparation method thereof

Abstract

The invention relates to the technical field of foamed light soil, and discloses industrial lithium slag solid waste based foamed light mixed soil and a preparation method thereof. Comprising the following steps: adding a foaming agent and a foam stabilizer into water, and uniformly stirring and mixing to obtain a foaming agent solution; the preparation method comprises the following steps: uniformly mixing cement, waste slurry and industrial lithium slag solid waste, adding into water, and uniformly stirring to obtain a premix; and adding the foaming agent solution into the premix, uniformly stirring and mixing, injecting into a mold for foaming, demolding and curing to obtain a foam blank, and drying the foam blank to obtain the foaming material. The lithium slag is reasonably applied to the foam light soil, so that the production cost of the foam light soil can be reduced, and the mechanical strength of the foam light soil can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of foamed lightweight soil, and in particular to an industrial lithium slag solid waste-based foamed lightweight mixed soil and a preparation method thereof. Background Art

[0002] Foam lightweight soil is a new type of lightweight thermal insulation material containing a large number of closed pores formed by mechanically foaming the foaming agent through the foaming system of a bubble machine, then evenly mixing the foam with cement slurry, and performing cast-in-place construction or mold forming through the pumping system of the foaming machine. It is naturally cured and is a bubble-like insulation material with the outstanding feature of forming closed foam pores inside the concrete. It has the advantages of light weight, high compressive strength, good overall performance, self-solidification, and thermal insulation.

[0003] Industrial lithium slag solid waste mainly comes from the lithium salt extraction process in the production of lithium batteries. It is a type of industrial by-product containing valuable metal elements. With the rapid development of new energy vehicles and portable electronic devices, the demand for lithium batteries has increased dramatically, and the amount of lithium slag solid waste generated has also increased rapidly. If these lithium slag solid wastes are not handled properly, they will not only cause waste of resources, but may also pollute the environment. The chemical composition of lithium slag solid waste is complex, containing a variety of metal oxides and silicate minerals, and has certain volcanic ash activity and adsorption properties. Therefore, the resource utilization of lithium slag solid waste has become a hot topic of research.

[0004] At present, in the construction industry, foamed lightweight soil is generally compounded with cement, sand, gravel, admixtures and water to form foamed lightweight soil for use in civil engineering and frame structures of buildings. In the prior art, foamed lightweight soil mostly uses cement as the main component, and cement accounts for a large proportion of the foamed lightweight soil, resulting in high cost.

[0005] Chinese patent publication number CN112358318 discloses a waterproof foam lightweight soil and its preparation method, which relates to the field of building materials. The waterproof foam lightweight soil provided by the invention includes the following components by mass: 40-78 parts of cement, 5-15 parts of desulfurized gypsum, 6-25 parts of ultrafine ash, and 8-16 parts of foaming agent. The waterproof foam lightweight soil is prepared by mixing cement, ultrafine ash, and desulfurized gypsum with water to obtain cement slurry; the foaming agent is made into foam and introduced into the cement slurry, and stirred to obtain the waterproof foam lightweight soil.

[0006] Chinese patent publication number CN113387721 discloses a novel foamed lightweight soil and a preparation method thereof, wherein the foamed lightweight soil is composed of a cementitious material slurry and foam; the foamed lightweight soil has a bubble rate of 60%-70%; the cementitious material slurry is mixed with a gel solid raw material and water at a water-to-solid ratio of 1:1.80-1:1.85, and the raw materials and their mass percentages in the gel solid raw material are: fly ash 10%-15%, cement 65%-78%, and ultrafine limestone powder 12%-20%; the foam is made by mixing a foaming agent and a foam stabilizer through air compression.

[0007] In the above technical solutions, foamed lightweight soil mostly uses cement as the main component, and cement accounts for a large proportion in the foamed lightweight soil, resulting in high production costs. How to apply industrial lithium slag solid waste to foamed lightweight soil to reduce its production costs is an urgent problem to be solved. Summary of the invention

[0008] In order to overcome the above problems of the prior art, the present invention provides an industrial lithium slag solid waste-based foamed lightweight mixed soil and a preparation method thereof. The present invention rationally applies lithium slag solid waste to foamed lightweight soil, which can not only reduce the production cost of the foamed lightweight soil, but also improve the mechanical strength of the foamed lightweight soil.

[0009] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions: A method for preparing industrial lithium slag solid waste-based foamed lightweight mixed soil comprises the following steps: S1, adding a foaming agent and a foam stabilizer into water and stirring to mix evenly to obtain a foaming agent solution; S2, mixing cement, waste mud and industrial lithium slag solid waste uniformly, adding into water and stirring uniformly to obtain a premix; S3, adding the foaming agent solution to the premix, stirring and mixing evenly, then injecting into a mold for foaming, demolding and curing to obtain a foam embryo, and drying the foam embryo.

[0010] In the technical solution of the present invention, cement, waste mud and industrial lithium slag solid waste are used as cementitious materials for foamed lightweight soil, and waste mud and industrial lithium slag solid waste are used as the main components of foamed lightweight soil, and then foamed to prepare foamed lightweight soil under the action of foaming agent and foam stabilizer. Waste mud and industrial lithium slag solid waste are used to replace traditional lightweight soil with cement as the main component. Since waste mud and industrial lithium slag solid waste are both wastes, the cost of raw materials is low, which greatly reduces the production cost of foamed lightweight soil, realizes the resource utilization of industrial lithium slag solid waste and waste mud, and is green and environmentally friendly. In addition, by compounding cement, waste mud and industrial lithium slag solid waste as cementitious materials, since the surface of industrial lithium slag has an uneven microscopic surface rough structure, it has a high bonding strength with cement, thereby improving the mechanical strength of foamed lightweight soil.

[0011] Preferably, in step S1, the foaming agent is sodium dodecylbenzene sulfonate.

[0012] Preferably, in step S2, the waste mud components include: clay, bentonite and water.

[0013] Preferably, in step S2, the mass ratio of cement, waste slurry and industrial lithium slag solid waste is 1:1:2.

[0014] Preferably, in step S3, the mass ratio of the foaming agent solution to the premix is ​​1:400-500.

[0015] Preferably, in step S3, the demoulding and curing time is 25-30 days.

[0016] Preferably, in the step S2, the industrial lithium slag solid waste is pretreated, comprising the following steps: S21, adding the industrial lithium slag solid waste into a sodium hydroxide solution for stirring treatment, filtering, washing and drying to obtain alkali-treated industrial lithium slag solid waste; S22, adding the alkali-treated industrial lithium slag solid waste to the biological treatment wastewater sludge, wherein the mass ratio of the alkali-treated industrial lithium slag solid waste to the biological treatment wastewater sludge is 1:10-15, stirring and mixing evenly, and letting it stand to obtain a mixture; S23, dehydrating the mixture, and cutting the dehydrated mixture into pieces to obtain a semi-solid mixture; S24, drying the semi-solid mixture, and then crushing it in a crusher to obtain.

[0017] In the technical solution of the present invention, as mentioned above, waste mud and industrial lithium slag solid waste are used to replace the traditional foamed lightweight soil with cement as the main component. Although the cost is greatly reduced, the following problems exist in the experimental process of the research and development team: industrial lithium slag solid waste is a porous structure material, acidic rainwater can enter the pores, and the durability of the foamed lightweight soil will also be affected by the erosion of acidic rainwater for a long time. In order to solve the above problems, the present invention pre-treats industrial lithium slag solid waste, first soaks the industrial lithium slag solid waste in an alkaline sodium hydroxide solution to neutralize its acidic components, and then mixes the industrial lithium slag solid waste with biological treatment wastewater sludge. The industrial lithium slag solid waste is a porous structure with a high specific surface area. Its pore structure provides a large number of physical adsorption sites for organic matter and suspended matter. When humus, microbial metabolites and nano oxides in the sludge contact with the porous material, they are adsorbed and fixed by physical forces such as van der Waals force and electrostatic attraction, blocking the pore structure of the industrial lithium slag solid waste, thereby preventing acid rainwater from entering the pore structure of the industrial lithium slag solid waste to cause erosion to the foam lightweight soil, and improving the durability of the foam lightweight soil. The volatile organic matter in the biological treatment wastewater sludge will be removed in the subsequent drying process to avoid harm to the soil and human health.

[0018] Preferably, in step S21, the concentration of the sodium hydroxide solution is 0.5-0.8wt%.

[0019] Preferably, in step S22, the standing time is 10-15 hours.

[0020] Preferably, in step S22, glass fiber waste is also added to the biological treatment wastewater sludge.

[0021] In the technical solution of the present invention, as described above, industrial lithium slag solid waste is mixed with biological wastewater sludge, and the biological wastewater sludge can block the pore structure of the lithium slag solid waste to prevent rainwater from corroding the foamed lightweight soil. However, a large amount of biological wastewater sludge is still left wrapped on the outside of the industrial lithium slag solid waste. This part of biological wastewater sludge is used as a component of the foamed lightweight soil. Experiments have found that biological wastewater sludge can reduce the mechanical strength of the foamed lightweight soil. To solve this problem, the present invention simultaneously adds glass fiber waste to the biological wastewater sludge, and the glass fiber waste forms a skeleton reinforcement effect in the biological wastewater sludge, thereby eliminating the negative effect of biological wastewater sludge on the mechanical strength of the foamed lightweight soil.

[0022] Preferably, the amount of the glass fiber waste added is 3-3.6 wt % of the biological treatment wastewater sludge.

[0023] In the technical solution of the present invention, as mentioned above, in order to eliminate the negative effect of biological treatment wastewater sludge on the mechanical strength of foamed lightweight soil, the amount of glass fiber waste added is at least 3wt% of the biological treatment wastewater sludge, but it was unexpectedly found during the experiment that when the amount of glass fiber waste added is greater than 3.6wt% of the biological treatment wastewater sludge, the anti-permeability performance of the foamed lightweight soil is greatly reduced. This may be because when excessive glass fiber is added, the compatibility of glass fiber and other components of the foamed lightweight soil is poor, and there is a large gap between the two, which leads to a decrease in the anti-permeability performance of the foamed lightweight soil. Therefore, the present invention simultaneously controls the amount of glass fiber waste added to be less than 3.6wt% of the biological treatment wastewater sludge.

[0024] Preferably, in step S24, the drying temperature is 50-70°C.

[0025] An industrial lithium slag solid waste-based foamed lightweight mixed soil is prepared by the method.

[0026] The present invention has the following beneficial effects: 1) Use waste mud and industrial lithium slag solid waste to replace traditional lightweight soil with cement as the main component. Since waste mud and industrial lithium slag solid waste are both waste, the cost of raw materials is low, which greatly reduces the production cost of foam lightweight soil, realizes the resource utilization of industrial lithium slag solid waste and waste mud, and is green and environmentally friendly; 2) By compounding cement, waste mud and industrial lithium slag solid waste as cementitious materials, the industrial lithium slag has a rough microscopic surface structure with uneven surfaces, which has a high bonding strength with cement and also improves the mechanical strength of foamed lightweight soil; 3) Pre-treat the industrial lithium slag solid waste by first soaking it in an alkaline sodium hydroxide solution to neutralize its acidic components, and then mix the industrial lithium slag solid waste with biological treatment wastewater sludge. The suspended matter and organic matter in the biological treatment wastewater sludge will be adsorbed into the pore structure of the industrial lithium slag solid waste, blocking the pore structure of the industrial lithium slag solid waste, thereby preventing acidic rainwater from entering the pore structure of the industrial lithium slag solid waste and corroding the foamed lightweight soil, thereby improving the durability of the foamed lightweight soil. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with specific embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0028] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0029] The industrial lithium slag solid waste used in the present invention is a by-product of the lithium salt extraction process in the lithium battery production process, and its main components are silicon dioxide, aluminum oxide, calcium oxide and potassium oxide, with a silicon dioxide content of 26.3%, an aluminum oxide content of 67.4%, a calcium oxide content of 4.9%, a potassium oxide content of 1.2%, and remaining impurities.

[0030] The biological wastewater treatment sludge used in the technical solution of the present invention comes from the biofilm method, such as the sediment produced in the secondary sedimentation tank in the sewage treatment process such as the biological filter, the biological rotary disk, and the partial biological contact oxidation tank.

[0031] Example 1 A method for preparing industrial lithium slag solid waste-based foamed lightweight mixed soil comprises the following steps: S1, adding sodium dodecylbenzene sulfonate foaming agent and cocamidopropyl betaine foam stabilizer into water and stirring and mixing evenly, wherein the mass ratio of the foaming agent, the foam stabilizer and water is 1:0.3:30, to obtain a foaming agent solution; S2, after cement, waste mud and industrial lithium slag solid waste are evenly mixed, they are added into water at a mass volume ratio of 1g / 2mL and stirred evenly, the mass ratio of cement, waste mud and industrial lithium slag solid waste is 1:1:2, the waste mud is a mixture of clay, bentonite and water, and the mass ratio of the three is 1:2:10, to obtain a premix; S3, adding the foaming agent solution to the premix at a mass ratio of 1:500, stirring and mixing evenly, and then injecting into a mold for foaming, demolding after 24 hours and curing for 30 days to obtain a foam embryo, and drying the foam embryo at 60°C.

[0032] The industrial lithium slag solid waste is pretreated, comprising the following steps: S21, adding the industrial lithium slag solid waste to a sodium hydroxide solution with a mass concentration of 0.5% at a mass volume ratio of 1 g / 100 mL for stirring treatment, filtering, washing and drying to obtain alkali-treated industrial lithium slag solid waste; S22, adding alkali-treated industrial lithium slag solid waste and glass fiber waste to biological treatment wastewater sludge, the mass ratio of alkali-treated industrial lithium slag solid waste to biological treatment wastewater sludge is 1:14, the amount of glass fiber waste added is 3.5wt% of the biological treatment wastewater sludge, stirring and mixing evenly, and standing for 13h to obtain a mixture; S23, dehydrating the mixture, and cutting the dehydrated mixture into pieces to obtain a semi-solid mixture; S24, drying the semi-solid mixture at 60° C., and then crushing it in a crusher to obtain.

[0033] Example 2 A method for preparing industrial lithium slag solid waste-based foamed lightweight mixed soil comprises the following steps: S1, adding sodium dodecylbenzene sulfonate foaming agent and cocamidopropyl betaine foam stabilizer into water and stirring and mixing evenly, wherein the mass ratio of the foaming agent, the foam stabilizer and water is 1:0.3:30, to obtain a foaming agent solution; S2, after cement, waste mud and industrial lithium slag solid waste are evenly mixed, they are added into water at a mass volume ratio of 1g / 2mL and stirred evenly, the mass ratio of cement, waste mud and industrial lithium slag solid waste is 1:1:2, the waste mud is a mixture of clay, bentonite and water, and the mass ratio of the three is 1:2:10, to obtain a premix; S3, adding the foaming agent solution to the premix according to the mass ratio of 1:400, stirring and mixing evenly, and then injecting into the mold for foaming, demolding after 24 hours and curing for 25 days to obtain a foam embryo, and drying the foam embryo at 60°C.

[0034] The industrial lithium slag solid waste is pretreated, comprising the following steps: S21, adding the industrial lithium slag solid waste to a sodium hydroxide solution with a mass concentration of 0.8% at a mass volume ratio of 1 g / 100 mL for stirring treatment, filtering, washing and drying to obtain alkali-treated industrial lithium slag solid waste; S22, adding alkali-treated industrial lithium slag solid waste and glass fiber waste to biological treatment wastewater sludge, the mass ratio of alkali-treated industrial lithium slag solid waste to biological treatment wastewater sludge is 1:12, the amount of glass fiber waste added is 3.2wt% of the biological treatment wastewater sludge, stirring and mixing evenly, and standing for 12h to obtain a mixture; S23, dehydrating the mixture, and cutting the dehydrated mixture into pieces to obtain a semi-solid mixture; S24, drying the semi-solid mixture at 50° C., and then crushing it in a crusher to obtain.

[0035] Example 3 A method for preparing industrial lithium slag solid waste-based foamed lightweight mixed soil comprises the following steps: S1, adding sodium dodecylbenzene sulfonate foaming agent and cocamidopropyl betaine foam stabilizer into water and stirring and mixing evenly, wherein the mass ratio of the foaming agent, the foam stabilizer and water is 1:0.3:30, to obtain a foaming agent solution; S2, after cement, waste mud and industrial lithium slag solid waste are evenly mixed, they are added into water at a mass volume ratio of 1g / 2mL and stirred evenly, the mass ratio of cement, waste mud and industrial lithium slag solid waste is 1:1:2, the waste mud is a mixture of clay, bentonite and water, and the mass ratio of the three is 1:2:10, to obtain a premix; S3, adding the foaming agent solution to the premix at a mass ratio of 1:500, stirring and mixing evenly, and then injecting into a mold for foaming, demolding after 24 hours and curing for 28 days to obtain a foam embryo, and drying the foam embryo at 60°C.

[0036] The industrial lithium slag solid waste is pretreated, comprising the following steps: S21, adding the industrial lithium slag solid waste to a sodium hydroxide solution with a mass concentration of 0.5% at a mass volume ratio of 1 g / 100 mL for stirring treatment, filtering, washing and drying to obtain alkali-treated industrial lithium slag solid waste; S22, adding alkali-treated industrial lithium slag solid waste and glass fiber waste to biological treatment wastewater sludge, the mass ratio of alkali-treated industrial lithium slag solid waste to biological treatment wastewater sludge is 1:13, the amount of glass fiber waste added is 3.3wt% of the biological treatment wastewater sludge, stirring and mixing evenly, and standing for 13h to obtain a mixture; S23, dehydrating the mixture, and cutting the dehydrated mixture into pieces to obtain a semi-solid mixture; S24, drying the semi-solid mixture at 70° C., and then crushing it in a crusher to obtain.

[0037] Example 4 A method for preparing industrial lithium slag solid waste-based foamed lightweight mixed soil comprises the following steps: S1, adding sodium dodecylbenzene sulfonate foaming agent and cocamidopropyl betaine foam stabilizer into water and stirring and mixing evenly, wherein the mass ratio of the foaming agent, the foam stabilizer and water is 1:0.3:30, to obtain a foaming agent solution; S2, after cement, waste mud and industrial lithium slag solid waste are evenly mixed, they are added into water at a mass volume ratio of 1g / 2mL and stirred evenly, the mass ratio of cement, waste mud and industrial lithium slag solid waste is 1:1:2, the waste mud is a mixture of clay, bentonite and water, and the mass ratio of the three is 1:2:10, to obtain a premix; S3, adding the foaming agent solution to the premix at a mass ratio of 1:500, stirring and mixing evenly, and then injecting into a mold for foaming, demolding after 24 hours and curing for 28 days to obtain a foam embryo, and drying the foam embryo at 60°C.

[0038] The industrial lithium slag solid waste is pretreated, comprising the following steps: S21, adding the industrial lithium slag solid waste to a sodium hydroxide solution with a mass concentration of 0.5% at a mass volume ratio of 1 g / 100 mL for stirring treatment, filtering, washing and drying to obtain alkali-treated industrial lithium slag solid waste; S22, adding alkali-treated industrial lithium slag solid waste and glass fiber waste to biological treatment wastewater sludge, the mass ratio of alkali-treated industrial lithium slag solid waste to biological treatment wastewater sludge is 1:15, the amount of glass fiber waste added is 3.6wt% of the biological treatment wastewater sludge, stirring and mixing evenly, and standing for 15h to obtain a mixture; S23, dehydrating the mixture, and cutting the dehydrated mixture into pieces to obtain a semi-solid mixture; S24, drying the semi-solid mixture at 60° C., and then crushing it in a crusher to obtain.

[0039] Example 5 A method for preparing industrial lithium slag solid waste-based foamed lightweight mixed soil comprises the following steps: S1, adding sodium dodecylbenzene sulfonate foaming agent and cocamidopropyl betaine foam stabilizer into water and stirring and mixing evenly, wherein the mass ratio of the foaming agent, the foam stabilizer and water is 1:0.3:30, to obtain a foaming agent solution; S2, after cement, waste mud and industrial lithium slag solid waste are evenly mixed, they are added into water at a mass volume ratio of 1g / 2mL and stirred evenly, the mass ratio of cement, waste mud and industrial lithium slag solid waste is 1:1:2, the waste mud is a mixture of clay, bentonite and water, and the mass ratio of the three is 1:2:10, to obtain a premix; S3, adding the foaming agent solution to the premix at a mass ratio of 1:500, stirring and mixing evenly, and then injecting into a mold for foaming, demolding after 24 hours and curing for 28 days to obtain a foam embryo, and drying the foam embryo at 60°C.

[0040] The industrial lithium slag solid waste is pretreated, comprising the following steps: S21, adding the industrial lithium slag solid waste to a sodium hydroxide solution with a mass concentration of 0.5% at a mass volume ratio of 1 g / 100 mL for stirring treatment, filtering, washing and drying to obtain alkali-treated industrial lithium slag solid waste; S22, adding alkali-treated industrial lithium slag solid waste and glass fiber waste to biological treatment wastewater sludge, the mass ratio of alkali-treated industrial lithium slag solid waste to biological treatment wastewater sludge is 1:10, and the amount of glass fiber waste added is 3wt% of the biological treatment wastewater sludge, stirring and mixing evenly, and standing for 10 hours to obtain a mixture; S23, dehydrating the mixture, and cutting the dehydrated mixture into pieces to obtain a semi-solid mixture; S24, drying the semi-solid mixture at 60° C., and then crushing it in a crusher to obtain.

[0041] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is: In step S2, the waste mud and industrial lithium slag solid waste are replaced with cement of equal mass.

[0042] The remaining steps are the same as those in Example 1.

[0043] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is: Industrial lithium slag solid waste has not been pretreated.

[0044] The remaining steps are the same as those in Example 1.

[0045] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that: In the pretreatment step S22, no glass fiber waste is added to the industrial lithium slag solid waste.

[0046] The remaining steps are the same as those in Example 1.

[0047] Comparative Example 4 The difference between Comparative Example 4 and Example 4 is that: The amount of glass fiber waste added was 3.7 wt% of the biological treatment wastewater sludge.

[0048] The remaining steps are the same as those in Example 4.

[0049] Performance Testing 1. Mechanical properties test: Using a 100 mm×100 mm×100 mm foam lightweight soil cube, refer to the "Autoclaved Aerated Concrete Performance Test Method" (GB / T 11969-2020), use a universal testing machine to test the unconfined compressive strength of the foam lightweight soil cube at a loading rate of 2.0±0.5 kN / s; the splitting tensile strength test is at a loading rate of 0.20±0.05 kN / s. The average strength of three parallel specimens is taken as the mechanical properties test result.

[0050]

[0051] 2. Durability test: A 100 mm×100 mm×100 mm foam lightweight soil cube was used, and the foam lightweight cube was immersed in a 0.1 mol / L hydrochloric acid solution for 30 days. After being taken out, it was placed in an oven for drying, and then the mechanical strength of the foam lightweight soil cube was tested.

[0052]

[0053] 3. Anti-seepage performance test: According to the test standard "Construction Industry Standard of the People's Republic of China - Foamed Concrete", the water absorption rate of foamed lightweight soil is tested. The test results are shown in the following table:

[0054] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing industrial lithium slag solid waste-based foamed lightweight mixed soil, characterized in that: The following steps are involved: S1, adding sodium dodecylbenzene sulfonate foaming agent and cocamidopropyl betaine foam stabilizer into water and stirring and mixing evenly to obtain a foaming agent solution; S2, after cement, waste mud and industrial lithium slag solid waste are mixed evenly, add water and stir evenly to obtain a premix; the waste mud components include: clay, bentonite and water; the industrial lithium slag solid waste is derived from the by-product of the lithium salt extraction process in the lithium battery production process, and its main components are silicon dioxide, aluminum oxide, calcium oxide and potassium oxide, wherein the silicon dioxide content is 26.3%, the aluminum oxide content is 67.4%, the calcium oxide content is 4.9%, the potassium oxide content is 1.2%, and the remaining impurities; S3, adding the foaming agent solution to the premix, stirring and mixing evenly, then injecting into a mold for foaming, demolding and curing to obtain a foam embryo, and drying the foam embryo.

2. The method for preparing an industrial lithium slag solid waste-based foamed lightweight mixed soil according to claim 1, characterized in that: In the step S2, the mass ratio of cement, waste slurry and industrial lithium slag solid waste is 1:1:

2.

3. The method for preparing an industrial lithium slag solid waste-based foamed lightweight mixed soil according to claim 1, characterized in that: In step S3, the mass ratio of the foaming agent solution to the premix is ​​1:400-500.

4. The method for preparing an industrial lithium slag solid waste-based foamed lightweight mixed soil according to claim 1, characterized in that: In step S3, the demoulding and curing time is 25-30 days.

5. The method for preparing an industrial lithium slag solid waste-based foamed lightweight mixed soil according to claim 1, characterized in that: The industrial lithium slag solid waste is pretreated, comprising the following steps: S21, adding the industrial lithium slag solid waste into a sodium hydroxide solution for stirring treatment, filtering, washing and drying to obtain alkali-treated industrial lithium slag solid waste; S22, adding the alkali-treated industrial lithium slag solid waste to the biological treatment wastewater sludge, wherein the mass ratio of the alkali-treated industrial lithium slag solid waste to the biological treatment wastewater sludge is 1:10-15, stirring and mixing evenly, and letting it stand to obtain a mixture; S23, dehydrating the mixture, and cutting the dehydrated mixture into pieces to obtain a semi-solid mixture; S24, drying the semi-solid mixture, and then crushing it in a crusher to obtain.

6. The method for preparing an industrial lithium slag solid waste-based foamed lightweight mixed soil according to claim 5, characterized in that: In step S21, the concentration of the sodium hydroxide solution is 0.5-0.8wt%.

7. The method for preparing an industrial lithium slag solid waste-based foamed lightweight mixed soil according to claim 5, characterized in that: In step S22, the standing time is 10-15 hours.

8. The method for preparing an industrial lithium slag solid waste-based foamed lightweight mixed soil according to claim 5, characterized in that: In the step S22, glass fiber waste is also added to the biological wastewater treatment sludge.

9. The method for preparing an industrial lithium slag solid waste-based foamed lightweight mixed soil according to claim 8, characterized in that: The added amount of the glass fiber waste is 3-3.6wt% of the biological treatment wastewater sludge.

10. The method for preparing an industrial lithium slag solid waste-based foamed lightweight mixed soil according to claim 5, characterized in that: In step S24, the drying temperature is 50-70°C.

11. An industrial lithium slag solid waste-based foamed lightweight mixed soil, characterized in that: The method is prepared by any one of claims 1 to 10.

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