Method for self-activated grading feeding of lithium residue red mud to strengthen heavy metal solidification and solidified formed material

Abstract

The application provides a method for self-activated grading feeding reinforced heavy metal solidification of lithium residue and red mud and a solidified and formed material. The method comprises the following steps: uniformly mixing solid raw materials with lithium residue to obtain a composite powder; dividing the composite powder into a first composite powder and a second composite powder; performing primary feeding by using the first composite powder and a first liquid raw material, and stirring to obtain a mixed slurry; continuously stirring the mixed slurry until the viscosity of the mixed slurry is greater than or equal to 10 5 mPa·s, performing secondary feeding by using the second composite powder and a second liquid raw material, and maintaining the stirring state; pouring the obtained product into a mold, performing vibration degassing, sealing, temperature rising curing and demolding to obtain the solidified and formed material, and completing the solidification of the heavy metal. The method provided by the application can realize the synchronous solidification and stabilization of the lithium residue and the red mud by using the grading feeding mode and the alkali activation effect of the red mud, and does not need to additionally add alkali, thereby providing a harmless method for the lithium residue.

Description

Technical Field

[0001] This invention belongs to the field of heavy metal solidification, specifically relating to a method for strengthening heavy metal solidification by self-excitation graded feeding of lithium slag and red mud, and a solidification molding material. Background Technology

[0002] With the rapid development of the electric vehicle industry, the demand for lithium battery resources is increasing rapidly. This has led to an increase in the scale of lithium ore mining and smelting, resulting in an increase in the stockpiling and generation of lithium slag. Currently, the production of one ton of lithium salt generates 8-10 tons of lithium slag. Its encroachment on land resources and potential pollution of soil and groundwater have placed a huge burden on the natural ecological environment. The cost of treating and disposing of lithium slag also greatly increases the cost of using lithium resources.

[0003] To address the aforementioned issues, traditional solidification and stabilization methods primarily employ cement solidification and alkali-activated solidification. These methods utilize cement bonding and aluminosilicate condensation to form a high-strength structure, thereby achieving the solidification and stabilization of heavy metals. However, the cement preparation process requires high-temperature clinker firing, resulting in high energy consumption and significant greenhouse gas emissions. Furthermore, carbonization can easily lead to a decrease in the strength of the molded material and the leaching of heavy metals. While alkali-activated solidification produces materials with high strength and stability, it requires a large amount of alkali, resulting in high costs.

[0004] Therefore, developing a novel lithium slag solidification and stabilization technology to achieve efficient, low-consumption, and stable solidification and stabilization of heavy metals inside lithium slag will greatly reduce the pollution risk and treatment costs of lithium slag, play a significant supporting role in the clean and efficient utilization of lithium resources, and help promote the development of related industries. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a method for enhancing the solidification of heavy metals in lithium slag and red mud through self-activation and graded feeding, as well as a solidification molding material. This invention eliminates the need for additional alkali solution; by utilizing the self-activation of red mud combined with graded feeding, it can enhance the solidification and stabilization of heavy metals within the lithium slag.

[0006] To achieve the above objectives, this invention provides a method for self-activated, graded feeding and enhanced heavy metal solidification of lithium slag red mud, wherein the method includes: S1. Mix the solid raw material with lithium slag evenly to obtain a composite powder; divide the composite powder into a first composite powder and a second composite powder. S2. The first liquid raw material and the first composite powder are fed into the first stage and stirred to obtain a mixed slurry; S3. Continue stirring the mixed slurry until the viscosity of the mixed slurry is ≥10. 5mPa·s, using a second composite powder and a second liquid raw material for secondary feeding, while maintaining a stirring state; S4. The product from step S3 is injected into the mold, and after vibration degassing, sealing, heating and curing, and demolding, a solidified molding material is obtained, thus completing the curing of heavy metals. The solid raw material is red mud; the first liquid raw material is sodium silicate solution and / or potassium silicate solution; and the second liquid raw material is sodium silicate solution and / or potassium silicate solution.

[0007] In some specific implementations, the process of dividing the composite powder into a first composite powder and a second composite powder refers to physical division, that is, dividing the composite powder into two parts, one part is called the first composite powder and the other part is called the second composite powder.

[0008] In some specific embodiments, preferably, the viscosity of the mixed slurry is 1×10⁻⁶ before secondary feeding. 5 mPa·s up to 1.5×10 5 mPa·s. In this invention, the raw materials in the mixed slurry need to form a preliminary gel, significantly increasing the viscosity of the mixed slurry, before secondary feeding. This allows the initial polymer structure to be encapsulated within the secondary structure formed after secondary feeding, thus enhancing the solidification effect on heavy metals in lithium slag. In this invention, the viscosity is measured using a single-cylinder rotational viscometer according to GB / T43876-2024 "Method for Determination of Viscosity of Cement Paste".

[0009] According to a specific embodiment of the present invention, preferably, in step S2, the amount of the first liquid raw material fed into the first composite powder is 30-50 parts based on 100 parts by mass; more preferably, the amount of the first liquid raw material fed into the first composite powder is 40-50 parts based on 100 parts by mass.

[0010] According to a specific embodiment of the present invention, preferably, in step S3, based on 100 parts by weight of the first composite powder, the amount of the second composite powder is 10-40 parts, and the amount of the second liquid raw material is 5-20 parts; more preferably, based on 100 parts by weight of the first composite powder, the amount of the second composite powder is 20-40 parts, and the amount of the second liquid raw material is 10-20 parts. The present invention utilizes a staged addition method to enhance the solidification and stabilization of heavy metals within lithium slag, achieving stable solidification of heavy metals under different environmental conditions.

[0011] In some specific embodiments, preferably, the amount of the first liquid raw material fed is 2 to 2.5 times the amount of the second liquid raw material fed.

[0012] According to a specific embodiment of the present invention, preferably, the first composite powder and the second composite powder, by weight, each comprise 10-30 parts of solid raw material and 70-100 parts of lithium slag; more preferably, by weight, the first composite powder and the second composite powder each comprise 10-20 parts of solid raw material and 85-100 parts of lithium slag; even more preferably, the first composite powder and the second composite powder each comprise 10-30 parts (preferably 10-20 parts, more preferably 10-15 parts) of solid raw material and 100 parts of lithium slag.

[0013] According to a specific embodiment of the present invention, preferably, the particle size of the red mud is <38 μm; the red mud is produced by the Bayer process and is dried, ground and sieved to obtain the required particle size.

[0014] According to a specific embodiment of the present invention, preferably, the concentrations of the first liquid raw material and the second liquid raw material are 1.9-2.1 mol / L, respectively; more preferably, the compositions of the first liquid raw material and the second liquid raw material are completely identical. In this invention, the sodium silicate solution is prepared by dissolving hydrated sodium silicate in water, and this sodium silicate solution does not need to be mixed with an alkali and can be used directly as a liquid raw material. The potassium silicate solution is prepared by dissolving hydrated potassium silicate in water.

[0015] According to a specific embodiment of the present invention, preferably, in steps S2 and S3, the stirring speed is 400-500 r / min, respectively.

[0016] According to a specific embodiment of the present invention, preferably, in step S3, the stirring time after the secondary feeding is 3-5 minutes.

[0017] According to a specific embodiment of the present invention, preferably, the curing temperature is 60-90℃ and the curing time is 1-3 hours.

[0018] According to a specific embodiment of the present invention, preferably, in step S1, the lithium slag, based on a total mass of 100%, comprises: SiO2 45.0%-60.0%, Al2O3 15.0%-23.0%, CaO 2.0%-6.0%, Na2O 4.0%-8.0%, and K2O 3.0%-10.0%.

[0019] The present invention also provides a solidified molding material, which is prepared by the above-mentioned method of strengthening the solidification of heavy metals by self-excitation graded feeding of lithium slag red mud.

[0020] In some specific embodiments, preferably, the curing rate of heavy metals in the cured molding material is 46%-100%; this curing rate is tested according to the method described in HJ / T 299-2007, specifically, the heavy metals include one or more combinations of thallium, niobium, tantalum, lead, chromium, copper, and zinc. More preferably, the curing rate is 92%-100%, and the heavy metals include thallium, niobium, tantalum, lead, chromium, and zinc; even more preferably, the curing rate is 99.5%-100%, and the heavy metals include thallium, niobium, lead, chromium, and zinc; even more preferably, the curing rate is 99.6%-100%, and the heavy metals include thallium, lead, and zinc.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The method for strengthening heavy metal solidification provided by the present invention utilizes the high alkalinity of red mud and combines the characteristics of lithium slag and red mud as the main components of aluminosilicates. With the help of liquid raw materials, the self-activation of lithium slag and red mud is achieved. This process does not require the addition of alkali to activate the reactivity of the raw materials, thereby reducing material loss.

[0022] (2) The method for strengthening the solidification of heavy metals provided by the present invention adopts a graded addition method, which utilizes the self-excitation of red mud to polymerize and grow aluminosilicate monomers. After the structure has initially gelled, the raw materials are added again to make the physical structure of the early stage embedded in the final formed structure, thereby promoting the solidification effect of heavy metals in lithium slag. The entire process only requires the secondary addition of basic raw materials and no additional agents are needed.

[0023] (3) The method for strengthening heavy metal solidification provided by this invention can achieve simultaneous solidification and stabilization of lithium slag and red mud. While effectively solidifying various heavy metals inside the lithium slag through the alkaline activation effect of red mud, it can also effectively solidify harmful substances in the red mud and maintain stability under various environmental simulation conditions. This method can be used for the harmless disposal of lithium slag and the disposal of red mud at the same time, effectively reducing the energy consumption, chemical consumption and cost of the lithium slag solidification process, realizing the synergistic harmless disposal process of lithium slag and red mud, and providing a low-consumption, high-efficiency and low-cost technical method for the harmless disposal of lithium slag.

[0024] (4) The heavy metal solidification method used in this invention does not require expensive basic raw materials. It can stimulate its own components based on the characteristics of waste residue components to form a high-strength structure based on silicon-aluminum-oxygen bonding, thereby achieving efficient solidification of internal heavy metals and realizing the solidification and stabilization of lithium slag at extremely low cost.

[0025] (5) The curing material provided by the present invention remains stable in a variety of simulated environments. The leaching concentration of the highly toxic heavy metal element thallium can be kept below 5 μg / L under most environmental conditions, which is lower than the emission limit of the "Emission Standard of Thallium Pollutants in Industrial Wastewater (DB36 / 1149-2019)". Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the process for the self-activated graded feeding method of lithium slag and red mud to enhance the solidification of heavy metals in this invention.

[0027] Figure 2 The heavy metal leaching concentrations (bar chart) and solidification rates (spot chart) of Examples 1-3 and Comparative Examples 1-3 under simulated acidic precipitation conditions are shown.

[0028] Figure 3 The graph shows the heavy metal solidification rate of Examples 1-3 and Comparative Examples 1-3 under simulated acidic precipitation conditions.

[0029] Figure 4 The heavy metal leaching concentration (bar chart) and curing rate (spot chart) of Examples 1-3 under different environments are shown.

[0030] Figure 5 The graph shows the heavy metal curing rate of Examples 1-3 under different environments.

[0031] Figure 6 The mechanical compressive strength of the cured materials in Examples 1-3 and Comparative Examples 1-3 is given. Detailed Implementation

[0032] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0033] It should be noted that, unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0034] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0035] It should be understood that the terms “comprising,” “including,” and / or “containing” as used herein specify the presence of the stated features, integers, steps, components, or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, steps, components, or combinations thereof.

[0036] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0037] In some specific implementations, such as Figure 1 As shown, the method for self-activated graded feeding and enhanced heavy metal solidification of lithium slag red mud of the present invention includes the following steps: S1. Using pure red mud as solid raw material, wherein the red mud comes from the Bayer process, the red mud is dried and then ground and sieved to obtain particles with a particle size <38μm; by mass, 10-30 parts of solid raw material and 70-100 parts of lithium slag are mixed thoroughly to obtain composite powder; the composite powder is divided into first composite powder and second composite powder. S2. Based on 100 parts by mass of the first composite powder, the first composite powder is fed with 30-50 parts of the first liquid raw material in a primary feeding process, and a mixed slurry is obtained under high-speed stirring conditions of 400-500 r / min; wherein, the first liquid raw material is a sodium silicate solution and / or potassium silicate solution with a concentration of 1.9-2.1 mol / L. S3. Maintain high-speed stirring of the mixed slurry for 10-20 minutes, observe the change in viscosity of the mixed slurry, and test the viscosity of the mixed slurry to be ≥1×10⁻⁶. 5 After reaching mPa·s, based on 100 parts by mass of the first composite powder, 10-40 parts of the second composite powder and 5-20 parts of the second liquid raw material are added in a secondary feeding process, and the mixture is stirred at a high speed of 400-500 r / min for 3-5 minutes; wherein, the second liquid raw material is a sodium silicate solution and / or a potassium silicate solution with a concentration of 1.9-2.1 mol / L. S4. Inject the product from step S3 into the mold and use a vibrator to distribute it evenly in the mold until no air bubbles are discharged. Then seal the mold and place it in a curing chamber to cure at 60-90℃ for 1-3 hours. After curing and molding, demold to obtain the cured material, thus completing the curing of heavy metals.

[0038] Example 1: This embodiment provides a method for enhancing the solidification of heavy metals through self-activated, graded feeding of lithium slag and red mud. The specific steps are as follows: S1. Using pure red mud as solid raw material, the red mud comes from the Bayer process. After drying the red mud, it is ground and sieved to obtain particles with a particle size <38μm. The solid raw material and lithium slag are mixed at a mass ratio of 10:100 and thoroughly mixed to obtain composite powder. The composite powder is divided into first composite powder and second composite powder for later use. The lithium slag, with a total mass of 100%, includes: SiO2 (46.0%), Al2O3 (18.0%), CaO (3.5%), Na2O (4.4%), and K2O (5.4%). S2. By mass, 100 parts of the first composite powder and 50 parts of the first liquid raw material are fed in a primary feed, and a mixed slurry is obtained under high-speed stirring at 500 r / min; wherein, the first liquid raw material is a hydrated sodium silicate solution with a concentration of 1.9 mol / L. S3. Maintain high-speed stirring of the mixed slurry for 10 minutes, observe the change in viscosity of the mixed slurry, and test the viscosity of the mixed slurry to be 1×10⁻⁶. 5 mPa·s, and then based on 100 parts by mass of the first composite powder, 40 parts by mass of the second composite powder and 20 parts by mass of the second liquid raw material are used for secondary feeding, and the high-speed stirring state of 500 r / min is maintained for 3 minutes; wherein, the composition of the second composite powder and the second liquid raw material used for secondary feeding is exactly the same as that of the first feeding. S4. Inject the product from step S3 into the mold and use a vibrator to distribute it evenly in the mold until no air bubbles are discharged. Then seal the mold and place it in a curing chamber to cure at 70°C for 1 hour. After curing and molding, demold to obtain the cured material, thus completing the curing of heavy metals.

[0039] Example 2: This embodiment provides a method for self-excited graded feeding and enhanced heavy metal solidification of lithium slag and red mud, which is basically the same as the steps in Embodiment 1, except that the raw material ratio of the composite powder in step S1 is different. By mass, the composite powder includes solid raw materials and lithium slag in a mass ratio of 20:100. The composite powder is divided into a first composite powder and a second composite powder for later use. The composition of the solid raw materials is the same as that in Embodiment 1. The remaining steps and parameters remain unchanged to obtain a cured molding material, thus completing the curing of the heavy metal.

[0040] Example 3: This embodiment provides a method for self-excited graded feeding and enhanced heavy metal solidification of lithium slag and red mud, which is basically the same as the steps in Embodiment 1, except that the raw material ratio of the composite powder in step S1 is different. By mass, the composite powder includes solid raw materials and lithium slag in a mass ratio of 30:100. The composite powder is divided into a first composite powder and a second composite powder for later use. The composition of the solid raw materials is the same as that in Embodiment 1. The remaining steps and parameters remain unchanged to obtain a cured molding material, thus completing the curing of the heavy metal.

[0041] Comparative Example 1: This comparative example describes a method for curing heavy metals, and the specific steps are as follows: Step (1): Mix the dried lithium slag with sodium hydroxide at a mass ratio of 100:10 and mix thoroughly to form a composite powder; Step (2): Mix 100 parts of composite powder with 50 parts of the first liquid raw material by mass, and stir at a high speed of 500 r / min to form a mixed slurry; wherein, the first liquid raw material is a hydrated sodium silicate solution with a concentration of 1.9 mol / L. Step (3): Inject the mixed slurry into the mold, and use a vibrator to make the mixed slurry in the mold evenly distributed in the mold until no air bubbles are discharged; seal the mold and place it in a curing box for curing at 70°C for 1 hour. After curing and molding, demold to obtain the cured material, thus completing the curing of heavy metals.

[0042] Comparative Example 2: This comparative example describes a method for curing heavy metals, and the specific steps are as follows: Step (1): Solid raw material preparation is made by mixing red mud and sodium hydroxide in a mass ratio of 100:10; wherein, the red mud comes from the Bayer process, and after drying, the red mud is ground and sieved to obtain particles with a particle size <38 μm; Step (2): Mix the solid raw materials and lithium slag at a mass ratio of 10:100 and mix thoroughly to form a composite powder; Step (3): By mass, 100 parts of composite powder and 50 parts of first liquid raw material are fed into the first stage. Under high-speed stirring at 500 r / min, a mixed slurry is formed. The mixed slurry is stirred at high speed for 10 minutes, and the change in viscosity of the mixed slurry is observed. The first liquid raw material is a hydrated sodium silicate solution with a concentration of 1.9 mol / L. Step (4): Inject the mixed slurry into the mold, and use a vibrator to make the mixed slurry in the mold evenly distributed in the mold until no air bubbles are discharged; seal the mold and place it in a curing box for curing at 70°C for 1 hour. After curing and molding, demold to obtain the cured material, thus completing the curing of heavy metals.

[0043] Comparative Example 3: This comparative example is a method for solidifying heavy metals, which is basically the same as that of comparative example 2. The difference is that in step (1), the solid raw material preparation uses pure red mud, which comes from the Bayer process. After the red mud is dried, it is ground and sieved to obtain particles with a particle size of <38 μm. The remaining steps and parameters remain unchanged to obtain a cured molding material, thus completing the curing of the heavy metal.

[0044] Test example: In this test case, the cured molding materials prepared in Examples 1-3 and Comparative Examples 1-3 were placed in different simulated environments to test seven heavy metals, namely thallium, niobium, tantalum, lead, chromium, copper and zinc, and their leaching concentrations were measured. The curing rate was calculated to explore the curing effect of heavy metals.

[0045] To make a more objective comparison, in Examples 1-3 and Comparative Examples 1-3, the sum of the amount of composite powder added (first composite powder + second composite powder) and the sum of the amount of liquid raw materials added (first liquid raw material + second liquid raw material) were controlled at a mass ratio of 2:1.

[0046] The simulated test environment includes: 1. Adjust the pH value to simulate an acidic or alkaline environment, with pH values ​​of 3.0, 6.5, and 10.0 respectively; 2. Dissolve sodium chloride to simulate a high-salt environment; the sodium chloride concentration is prepared to be 0.1 mol / L. 3. Simulate an acidic precipitation environment according to the "Solid Waste Leaching Toxicity Leaching Method: Sulfuric Acid and Nitric Acid Method (HJT 299-2007)"; 4. Landfill leachate environment simulated according to the "Solid Waste Leaching Toxicity Leaching Method Acetic Acid Buffer Solution Method (HJ_T 300-2007)".

[0047] The formula for calculating the solidification rate is: Solidification rate = (Total heavy metal content in lepidolite tailings + Total heavy metal content in red mud - Leaching concentration × Leaching volume) / (Total heavy metal content in lepidolite tailings + Total heavy metal content in red mud) × 100%.

[0048] The test results are as follows: Figure 2 To simulate the leaching concentration and curing rate of heavy metals in the cured molding materials prepared in Examples 1-3 and Comparative Examples 1-3 under acidic precipitation conditions, the following methods were used: Figure 2 It can be seen that Examples 1-3 can control the leaching concentration of various metals within a low range, especially showing better curing effects for thallium, lead, and zinc. Meanwhile, Figure 3 Statistics were compiled under simulated acid precipitation conditions. Figure 2The distribution of solidification rates of seven heavy metals in the sample was determined by... Figure 3 It can be seen that Example 1 achieved a curing rate of nearly 100% for the seven heavy metals in an acidic precipitation environment, demonstrating a good curing effect; while Comparative Examples 1-3 showed a wider statistical distribution of curing rates for multiple metals, with some cases below 96%. Therefore, combined with... Figure 2 and Figure 3 As can be seen, the red mud synergistic process and graded addition process provided by the present invention can effectively improve the solidification effect on various metals (especially thallium).

[0049] Furthermore, by comparing the solidification rate statistics of Comparative Example 2 and Comparative Example 3, it can be seen that the alkalinity of red mud itself can activate the material, and the red mud synergistic process can replace the addition of sodium hydroxide. While reducing the use of chemical agents, it can also improve the solidification effect on heavy metals in lithium slag.

[0050] Furthermore, by comparing Comparative Example 3 with Examples 1-3... Figure 2 , Figure 3 The results show that staged addition of red mud can significantly improve the solidification effect on heavy metals such as Tl, Zn, Cu, and Pb. Taking the highly toxic heavy metal thallium as an example, the thallium leaching concentration in Comparative Example 3 was 1.32 μg / L, while the thallium leaching concentrations in Examples 1-3 were 1.11 μg / L, 0.26 μg / L, and 0.00 μg / L, respectively. Therefore, staged addition of red mud can significantly reduce the leaching concentration of heavy metal elements and improve the solidification rate.

[0051] Examples 1-3 were tested for heavy metal leaching concentration and solidification rate under acidic, alkaline, neutral, high-salt, acidic precipitation, and landfill leachate conditions, respectively. The results are as follows: Figure 4 , Figure 5 As shown; by Figure 4 , Figure 5 It can be seen that, under the influence of acidic, alkaline, neutral, high-salt, and acidic precipitation environments, the leaching concentration of Tl in Examples 1-3 remained below 5 μg / L, meeting the emission limit of 5 μg / L stipulated in the "Emission Standard for Thallium Pollutants in Industrial Wastewater (DB36 / 1149-2019)". Furthermore, the solidification effect was even better in high-salt and acidic precipitation environments, especially in Example 3 where the Tl solidification rate reached 99.99%. In addition, from... Figure 5 Different statistical environments Figure 4 The solidification rate distribution of the seven metals in the examples shows that the solidification rates for thallium, niobium, tantalum, lead, chromium, and zinc are all above 92%, with most falling between 98% and 100%. These results indicate that the solidification method of this invention can stably fix heavy metals in lithium slag under most environmental conditions.

[0052] Figure 6 The mechanical compressive strength of the cured materials in Examples 1-3 and Comparative Examples 1-3 was tested. Figure 6 It can be seen that the mechanical compressive strength of the cured materials in Examples 1-3 is better than that in Comparative Examples 1-3. Therefore, the heavy metal curing method provided by the present invention forms a high-strength structure.

Claims

1. A method for self-activated, graded feeding and enhanced heavy metal solidification of lithium slag red mud, wherein, The method includes: S1. Mix the solid raw material with lithium slag evenly to obtain a composite powder; divide the composite powder into a first composite powder and a second composite powder. S2. The first liquid raw material and the first composite powder are fed into the first stage and stirred to obtain a mixed slurry; S3. Continue stirring the mixed slurry until the viscosity of the mixed slurry is ≥10. 5 mPa·s, using a second composite powder and a second liquid raw material for secondary feeding, while maintaining a stirring state; S4. Inject the product from step S3 into the mold, and after vibration degassing, sealing, heating curing, and demolding, obtain the cured molding material to complete the curing of heavy metals. The solid raw material is red mud; The first liquid raw material is a sodium silicate solution and / or a potassium silicate solution, and the second liquid raw material is a sodium silicate solution and / or a potassium silicate solution.

2. The method according to claim 1, wherein, In step S2, based on 100 parts by weight of the first composite powder, the amount of the first liquid raw material fed is 30-50 parts; Preferably, based on 100 parts by weight of the first composite powder, the amount of the first liquid raw material fed is 40-50 parts.

3. The method according to claim 1, wherein, In step S3, based on 100 parts by weight of the first composite powder, the amount of the second composite powder is 10-40 parts, and the amount of the second liquid raw material is 5-20 parts. Preferably, based on 100 parts by weight of the first composite powder, the amount of the second composite powder is 20-40 parts, and the amount of the second liquid raw material is 10-20 parts.

4. The method according to any one of claims 1-3, wherein, By weight, the first composite powder and the second composite powder each comprise 10-30 parts of solid raw materials and 70-100 parts of lithium slag. Preferably, by mass, the first composite powder and the second composite powder each comprise 10-20 parts of solid raw material and 85-100 parts of lithium slag.

5. The method according to claim 1, wherein, The particle size of the red mud is <38 μm.

6. The method according to any one of claims 1-3, wherein, The concentrations of the first liquid raw material and the second liquid raw material are 1.9-2.1 mol / L, respectively.

7. The method according to claim 1, wherein, In steps S2 and S3, the stirring speed is 400-500 r / min, respectively.

8. The method according to claim 1, wherein, In step S3, the stirring time after secondary feeding is 3-5 minutes.

9. The method according to claim 1, wherein, The curing temperature is 60-90℃, and the curing time is 1-3 hours.

10. A solidified molding material, which is prepared by the method of self-excited graded feeding and enhanced solidification of heavy metals from lithium slag red mud as described in any one of claims 1-9.

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