Multi-stage ultrasonic and graded synergistic reinforcement method for heavy metal solidification of lithium slag and solidified formed material

Abstract

This invention discloses a method for synergistic enhancement of heavy metal solidification in lithium slag using multi-stage ultrasound and particle size distribution, and a solidified molding material, belonging to the technical field of solid waste pollution harmlessness and resource utilization. The method includes: mixing hydroxide and silicate, activating them through a single stage of ultrasound to obtain a mixed solidifying agent; grinding and sieving lithium slag and blast furnace slag separately, then grading the particle size of the lithium slag and blast furnace slag; mixing the mixed solidifying agent, the graded lithium slag, and the graded blast furnace slag, activating them through a second stage of ultrasound to obtain a solidification precursor; injecting the solidification precursor into a mold, strengthening it through a third stage of ultrasound, then sealing and curing it, followed by demolding to obtain the solidified molding material. This invention enables the simultaneous utilization and resource utilization of lithium slag and blast furnace slag, while simultaneously achieving the solidification and stabilization of multiple heavy metals, and forming a solidified molding material with high mechanical strength.

Description

Technical Field

[0001] This invention belongs to the field of solid waste pollution harmlessness and resource utilization technology, and specifically relates to a method for solidifying lithium slag heavy metals by multi-segment ultrasound and gradation synergistic enhancement, and solidification molding materials. Background Technology

[0002] With the rapid development of the new energy industry, the demand for lithium batteries is increasing. Lithium in lithium batteries mainly comes from salt lake brine, lithium ore smelting, and lithium battery waste recycling. During lithium ore smelting, approximately 8-10 tons of lithium slag are generated for every ton of lithium salt extracted. The main resource utilization method for lithium slag is its use in the cement and concrete industry, but the overall utilization rate is less than 20%. Faced with the rapidly increasing volume of lithium slag in the future, effective recycling cannot be achieved. Furthermore, due to the composition and pollution characteristics of lithium slag, large-scale stockpiling can lead to land encroachment, lithium slag dust, and leachate pollution of soil and groundwater, threatening the surrounding environment and ecological security.

[0003] Lithium slag contains components such as silica, alumina, calcium oxide, and iron oxide, and has been used as a raw material for cement, concrete, building materials, ceramics, and molecular sieves. However, the migration and release of various heavy metals within the lithium slag during these resource recovery processes have not received sufficient attention or effective control. Furthermore, these resource recovery processes often require high temperatures and high pressures of 400–1450°C, significantly increasing energy consumption and equipment requirements, thus limiting the scale of lithium slag resource recovery.

[0004] The annual production of blast furnace slag, a major solid waste, exceeds 330 million tons. In the early stages, its main resource utilization method was as a raw material for cement and concrete in the construction industry. However, according to recent statistical yearbook data, cement production has declined by more than 15% over the past four years, and the resource utilization path of blast furnace slag needs to be developed and expanded.

[0005] In response to the dilemma of harmless disposal and resource utilization of lithium slag and blast furnace slag, there is an urgent need to develop a resource utilization method that can simultaneously dispose of lithium slag and blast furnace slag, while also solidifying and stabilizing various heavy metals in them. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide a method for multi-segment ultrasonic and gradation-based synergistic enhancement of heavy metal solidification in lithium slag, as well as a solidified molding material. This invention enables the simultaneous utilization and resource recovery of lithium slag and blast furnace slag, while simultaneously achieving the solidification and stabilization of various heavy metals within them, and forming a solidified molding material with high mechanical strength.

[0007] To achieve the above objectives, the first aspect of the present invention provides a method for multi-segment ultrasonic and graded synergistic enhancement of heavy metal solidification in lithium slag, comprising the following steps: (1) The hydroxide and silicate are mixed and activated by a period of ultrasound to obtain a mixed curing agent; (2) Grind and sieve the lithium slag and blast furnace slag separately, and then perform particle size distribution on the lithium slag and blast furnace slag to obtain the graded lithium slag and the graded blast furnace slag. (3) The mixed curing agent, the graded lithium slag and the graded blast furnace slag are mixed and excited by two-stage ultrasound to obtain a curing precursor; (4) The cured precursor is injected into the mold, strengthened by three-stage ultrasound, then sealed and cured, and then demolded to obtain the cured molding material.

[0008] According to a specific embodiment of the present invention, preferably, in step (1), the hydroxide includes sodium hydroxide and potassium hydroxide, etc.; the silicate includes a hydrated sodium silicate solution. More preferably, the mass content of sodium silicate in the hydrated sodium silicate solution is 35.4%~41.0%. More preferably, by mass parts, the amount of sodium hydroxide added is 10~25 parts, the amount of potassium hydroxide added is 5~15 parts, and the amount of hydrated sodium silicate solution added is 80~100 parts.

[0009] According to a specific embodiment of the present invention, preferably, in step (1), the ultrasonic power of the ultrasonic segment is 200~300W, the ultrasonic frequency is 40~50kHz, and the ultrasonic time is 60~120 seconds.

[0010] In step (1) of this invention, potassium hydroxide solid powder, sodium hydroxide solid powder, and hydrated sodium silicate solution are preferably mixed to obtain a milky white compound activator. Then, the compound activator is subjected to ultrasonic activation using an ultrasonic oscillator to promote the full dissolution of the solid powder in the hydrated sodium silicate solution. Ultrasonic action is used to fully activate the components in the solution, resulting in a clear and transparent mixed curing agent. The mixed curing agent of this invention preferably uses a compound of sodium hydroxide and potassium hydroxide, with synergistic ultrasonic activation. This improves the reactivity of the mixed curing agent with lithium slag and blast furnace slag, enhances the compatibility of the mixed curing agent, and ensures the activation of the components in lithium slag and blast furnace slag.

[0011] According to a specific embodiment of the present invention, preferably, in step (2), the total mass of the lithium slag is 100%, which includes: 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%.

[0012] According to a specific embodiment of the present invention, preferably, in step (2), the total mass of the blast furnace slag is 100%, which includes: CaO 36.0%~44.0%, SiO2 30.0%~36.0%, Al2O3 8.0%~16.0% and MgO 4.0%~13.0%.

[0013] According to a specific embodiment of the present invention, preferably, in step (2), after grinding the lithium slag and blast furnace slag separately, the ground lithium slag is passed through a 200-mesh sieve (<75μm) to obtain lithium slag with an average particle size of 1~25μm as graded lithium slag, and the ground blast furnace slag is passed through a 400-mesh sieve (<38μm) to obtain blast furnace slag with an average particle size of 1~13μm as graded blast furnace slag.

[0014] In step (2) of the present invention, lithium slag and blast furnace slag are ground and sieved respectively. By using the particle size distribution of lithium slag and blast furnace slag within the above range, the particle size difference between lithium slag and blast furnace slag can be utilized for matching. The synergy of the two raw materials is achieved through particle size distribution. The differences in the dissolution and molding process caused by the different components and particle sizes of the two raw materials, as well as the differences in the reaction rate in the mixed curing agent, promote the improvement of the strength of the cured material and the enhancement of the curing effect.

[0015] According to a specific embodiment of the present invention, preferably, in step (3), based on the total amount of 100 parts by mass of the graded lithium slag and the graded blast furnace slag, the amount of the mixed curing agent added is 50 to 70 parts.

[0016] According to a specific embodiment of the present invention, preferably, in step (3), based on the total amount of 100 parts by mass of the graded lithium slag and the graded blast furnace slag, the amount of graded lithium slag added is 70-90 parts, and the amount of graded blast furnace slag added is 10-30 parts.

[0017] According to a specific embodiment of the present invention, preferably, in step (3), the ultrasonic power of the two-segment ultrasound is 200~300W, the ultrasonic frequency is 40~50kHz, and the ultrasonic time is 60~120 seconds.

[0018] According to a specific embodiment of the present invention, preferably, in step (3), the mixed curing agent, the graded lithium slag and the graded blast furnace slag are mixed by mechanical stirring at a speed of 200~400 r / min, and then excited by two-stage ultrasound to obtain a curing precursor.

[0019] In step (3) of the present invention, it is preferable to mix the mixed curing agent, graded lithium slag and graded blast furnace slag at high speed to obtain a mixed slurry. Then, the mixed slurry is subjected to two-stage ultrasonic excitation by an ultrasonic oscillator to promote full contact between the interface of the mixed curing agent, blast furnace slag and lithium slag, further enhance the reactivity of the alkali component, and promote the full dissolution and reaction of the graded blast furnace slag and lithium slag to obtain the curing precursor.

[0020] According to a specific embodiment of the present invention, preferably, in step (4), the ultrasonic power of the three ultrasonic segments is 200~300W, the ultrasonic frequency is 40~50kHz, and the ultrasonic time is 60~120 seconds. More preferably, the ultrasonic time is until no gas is discharged from the solidified precursor.

[0021] According to a specific embodiment of the present invention, preferably, in step (4), the cured precursor is injected into the mold, and the cured precursor is stirred by an ultrasonic vibrating rod at a speed of 100~200 r / min. It is then strengthened by three-stage ultrasound, sealed and cured, and then demolded to obtain the cured molding material.

[0022] According to a specific embodiment of the present invention, preferably, in step (4), the temperature for sealing and curing is 60~90℃ and the time is 1.0~4.0h. Specifically, the temperature for sealing and curing is 60℃ and the time is 1h.

[0023] In step (4) of this invention, the solidified precursor is injected into a mold, and the solidified precursor is uniformly stirred and subjected to three-stage ultrasonic strengthening using an ultrasonic vibrator. This promotes the uniform distribution of the solidified precursor in the mold and facilitates gas discharge, achieving structural continuity of the precursor. Simultaneously, it strengthens the contact reaction between the mixed curing agent and the blast furnace slag and lithium slag. The ultrasonic time is preferably until no gas is discharged. The mold is then sealed and cured in a curing chamber. After sealing and curing, the mold is demolded to obtain the solidified material, completing the solidification of heavy metals in the lithium slag.

[0024] The second aspect of the present invention provides a curing molding material, which is prepared by the above-mentioned multi-segment ultrasonic and gradation synergistic enhancement method for curing heavy metals in lithium slag.

[0025] According to a specific embodiment of the present invention, preferably, the unconfined compressive strength of the cured molding material is 27 MPa or more, more preferably 27 MPa to 35 MPa. Specifically, this compressive strength is the compressive strength measured after curing at 60°C for 1 hour.

[0026] According to a specific embodiment of the present invention, preferably, the curing rate of the heavy metals in the cured molding material is 90.00%~100.00%. This curing rate is obtained by testing according to the method described in HJ / T 299-2007. Specifically, the heavy metals include one or more of chromium, copper, zinc, niobium, tantalum, thallium, and lead; more specifically, the heavy metals include chromium, copper, zinc, niobium, tantalum, thallium, and lead.

[0027] The present invention has at least the following beneficial effects: (1) The mixed curing agent of the present invention preferably adopts a compound of sodium hydroxide and potassium hydroxide, and is activated by a first stage of ultrasonication. Based on the ultrasonic cavitation effect, it promotes the dissolution and homogeneous distribution of alkali, activates its activity, ensures its reactivity with the solid waste raw materials used in the present invention, and improves the compatibility of the mixed curing agent, ensuring the activation of the components of lithium slag and blast furnace slag, thereby facilitating the formation of a multi-gel combination structure in the subsequent process, and thus promoting the efficient curing and stabilization of various heavy metals in the waste slag.

[0028] (2) The multi-stage ultrasonic process of the present invention can effectively improve the solidification effect of heavy metals inside lithium slag and the mechanical strength of solidified molding material. The first stage of ultrasonic activation activates the compound activator, the second stage of ultrasonic stimulation promotes the solid-liquid interface reaction activity of mixed curing agent with lithium slag and blast furnace slag, and the third stage of ultrasonic promotes the homogeneous distribution and further reaction of the curing precursor in the mold, thereby promoting the synchronous and efficient solidification and stabilization effect of heavy metals inside lithium slag and improving the mechanical strength of solidified molding material.

[0029] (3) The present invention uses blast furnace slag, a large industrial solid waste. The raw material output is large and the industry is widely distributed. The raw material can be obtained nearby in a wide range, reducing transportation costs and raw material acquisition costs. It helps to solidify and stabilize the heavy metals in lithium slag in different regions and improves the feasibility of the present invention in actual engineering applications.

[0030] (4) The present invention uses the particle size difference between blast furnace slag and lithium slag to form a particle size distribution combination. By the difference in reaction rate of raw materials with different particle sizes in the mixed curing agent, the surface of lithium slag with larger particle size partially dissolves to provide reactive sites, and the blast furnace slag with smaller particle size completely dissolves and forms a complete coating on the lithium slag, thereby achieving effective curing of multiple heavy metals in lithium slag and improving the mechanical strength of the cured molding material.

[0031] (5) This invention employs a solid waste combination method to solidify lithium slag-blast furnace slag, simultaneously achieving the solidification and stabilization of chromium (Cr), copper (Cu), zinc (Zn), niobium (Nb), tantalum (Ta), thallium (Tl), and lead (Pb). Furthermore, while addressing the potential risks of large-scale solid waste accumulation, the solidified molding material of this invention possesses high mechanical strength and high stability in various environments, making it usable as brick material. This improves resource utilization, broadens the pathways for the disposal of solid waste derivatives, reduces the disposal and harmless treatment costs of bulk solid waste, and alleviates the pressure on demand for non-renewable mineral resources.

[0032] In summary, this invention employs multi-segment ultrasound, performing ultrasound at the mixing and curing agent preparation stage, the curing precursor preparation stage, and the venting stage in the mold. This enhances the reactivity of the mixing and curing agent and its contact reaction with lithium slag and blast furnace slag, promotes the uniform distribution of the curing precursor in the mold, and facilitates gas venting, achieving structural continuity of the precursor. Simultaneously, by combining the particle size distribution effect of lithium slag and blast furnace slag, it achieves simultaneous curing and stabilization of multiple heavy metals in lithium slag, and realizes the simultaneous resource utilization of lithium slag and blast furnace slag. This invention produces a cured molding material with high mechanical strength, and the cured molding material remains stable in various environments (such as acid, alkali, salt, and high-salt environments), thus ensuring the stability and reliability of the cured molding material during application. This invention is used for the utilization of large quantities of lithium slag and blast furnace slag, constructing a simple, low-energy-consumption, low-cost, safe, and stable waste slag co-processing for harmless and resource-based treatment and disposal. It is highly feasible and achieves the triple goals of waste treatment, harmlessness, and resource utilization. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the process of the multi-segment ultrasonic and gradation synergistic enhancement method for lithium slag heavy metal solidification in a specific embodiment of the present invention.

[0034] Figure 2 Examples and comparative examples compare the leaching concentration and solidification rate of heavy metals in lithium slag.

[0035] Figure 3 The solidification rate distribution of various heavy metals in lithium slag is shown in the examples and comparative examples.

[0036] Figure 4 The examples show the leaching concentration and curing rate of heavy metals in different environments.

[0037] Figure 5 The following is an example of the curing rate distribution of heavy metals in different environments.

[0038] Figure 6 The mechanical strength of the cured molding materials in the examples and comparative examples. Detailed Implementation

[0039] To provide a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the present invention will now be described in detail below, but this should not be construed as limiting the scope of the invention.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] In a specific embodiment of the present invention, such as Figure 1 As shown, the multi-segment ultrasonic and gradation synergistic enhancement method for lithium slag heavy metal solidification of the present invention includes the following steps: (1) Sodium hydroxide, potassium hydroxide and hydrated sodium silicate solution are mixed to obtain a compound activator, and then activated by a section of ultrasound to obtain a mixed curing agent; (2) Grind and sieve the lithium slag and blast furnace slag separately, and then perform particle size distribution on the lithium slag and blast furnace slag to obtain the graded lithium slag and the graded blast furnace slag. (3) The mixed curing agent, the graded lithium slag and the graded blast furnace slag are mixed by high-speed mechanical stirring and excited by two-stage ultrasound to obtain a curing precursor; (4) The curing precursor is injected into the mold, the curing precursor is stirred evenly, and it is strengthened by three-stage ultrasound to achieve vibration and air exhaust of the curing precursor. After sealing and curing, it is demolded to obtain the cured molding material.

[0045] Example 1

[0046] Step (1) Potassium hydroxide solid powder, sodium hydroxide solid powder and hydrated sodium silicate solution are mixed by mechanical stirring at a stirring speed of 300 r / min. By mass, the amount of sodium hydroxide solid powder added is 15 parts, the amount of potassium hydroxide solid powder added is 10 parts, and the amount of hydrated sodium silicate solution added is 100 parts. The mass content of sodium silicate in the hydrated sodium silicate solution is 38.0%. After mixing, a milky white compound activator is obtained. Then, the compound activator is ultrasonically activated by an ultrasonic oscillator with an ultrasonic power of 300 W, an ultrasonic frequency of 40 kHz and an ultrasonic time of 120 seconds to obtain a clear and transparent mixed curing agent.

[0047] Step (2) The lithium slag and blast furnace slag are ground and sieved separately. The total mass of the lithium slag is 100%, which includes: SiO2 (46.0%), Al2O3 (18.0%), CaO (3.5%), Na2O (4.4%) and K2O (5.4%). The total mass of the blast furnace slag is 100%, which includes: CaO (42.0%), SiO2 (34.2%), Al2O3 (10.6%) and MgO (6.5%). The ground lithium slag is sieved through a 200-mesh sieve (<75μm) to obtain lithium slag with an average particle size of 25μm as graded lithium slag. The ground blast furnace slag is sieved through a 400-mesh sieve (<38μm) to obtain blast furnace slag with an average particle size of 13μm as graded blast furnace slag.

[0048] Step (3) The mixed curing agent, graded lithium slag, and graded blast furnace slag are thoroughly mixed by high-speed mechanical stirring at a stirring speed of 300 r / min. By mass, the amount of mixed curing agent added is 50 parts, the amount of graded lithium slag added is 70 parts, and the amount of graded blast furnace slag added is 30 parts to obtain a mixed slurry. Then, the mixed slurry is subjected to two-stage ultrasonic excitation using an ultrasonic oscillator with an ultrasonic power of 200 W, an ultrasonic frequency of 40 kHz, and an ultrasonic time of 60 seconds to obtain a curing precursor.

[0049] Step (4) Inject the cured precursor into the mold, use an ultrasonic vibrator to uniformly stir the cured precursor and perform three-stage ultrasonic strengthening. The stirring speed is 100r / min, the ultrasonic power is 200W, the ultrasonic frequency is 40kHz, and the ultrasonic time is 60 seconds until no gas is discharged. Then seal the mold and cure it in a curing chamber at a curing temperature of 60℃ for 1 hour. After demolding, the cured molding material is obtained.

[0050] Example 2

[0051] Steps (1) to (2) are consistent with steps (1) to (2) of Example 1.

[0052] Step (3) The mixed curing agent, graded lithium slag, and graded blast furnace slag are thoroughly mixed by high-speed mechanical stirring at a stirring speed of 300 r / min. By mass, the amount of mixed curing agent added is 50 parts, the amount of graded lithium slag added is 90 parts, and the amount of graded blast furnace slag added is 10 parts to obtain a mixed slurry. Then, the mixed slurry is subjected to two-stage ultrasonic excitation using an ultrasonic oscillator with an ultrasonic power of 200 W, an ultrasonic frequency of 40 kHz, and an ultrasonic time of 60 seconds to obtain a curing precursor.

[0053] Step (4) is the same as step (4) in Example 1.

[0054] Example 3

[0055] Steps (1) to (2) are consistent with steps (1) to (2) of Example 1.

[0056] Step (3) The mixed curing agent, graded lithium slag, and graded blast furnace slag are thoroughly mixed by high-speed mechanical stirring at a stirring speed of 300 r / min. By mass, the amount of mixed curing agent added is 50 parts, the amount of graded lithium slag added is 80 parts, and the amount of graded blast furnace slag added is 20 parts to obtain a mixed slurry. Then, the mixed slurry is subjected to two-stage ultrasonic excitation using an ultrasonic oscillator with an ultrasonic power of 200 W, an ultrasonic frequency of 40 kHz, and an ultrasonic time of 60 seconds to obtain a curing precursor.

[0057] Step (4) is the same as step (4) in Example 1.

[0058] Comparative Example 1

[0059] Step (1) Sodium hydroxide solid powder and hydrated sodium silicate solution are mixed by mechanical stirring at a stirring speed of 300 r / min. The amount of sodium hydroxide solid powder added is 25 parts by mass, and the amount of hydrated sodium silicate solution added is 100 parts by mass. The mass content of sodium silicate in the hydrated sodium silicate solution is 38.0%. After mixing, a milky white compound activator is obtained.

[0060] Step (2) The lithium slag is ground and sieved. The lithium slag used is the same as that in Example 1. The ground lithium slag is passed through a 200-mesh sieve (<75μm) to obtain lithium slag with an average particle size of 25μm as graded lithium slag.

[0061] Step (3) The compound activator and the graded lithium slag are thoroughly mixed by high-speed mechanical stirring at a speed of 300 r / min. The amount of compound activator added is 50 parts by mass, and the amount of graded lithium slag added is 100 parts, to obtain the solidified precursor.

[0062] Step (4) Inject the curing precursor into the mold and stir the curing precursor evenly at a speed of 100 r / min until no gas is discharged; then seal the mold and cure it in a curing chamber at a curing temperature of 60℃ for 1 hour. After demolding, the cured molding material is obtained.

[0063] Comparative Example 2

[0064] Step (1) mix potassium hydroxide solid powder, sodium hydroxide solid powder and hydrated sodium silicate solution by mechanical stirring at a stirring speed of 300 r / min. By mass, the amount of sodium hydroxide solid powder added is 15 parts, the amount of potassium hydroxide solid powder added is 10 parts, and the amount of hydrated sodium silicate solution added is 100 parts. The mass content of sodium silicate in the hydrated sodium silicate solution is 38.0%. After mixing, a milky white compound activator is obtained.

[0065] Steps (2) to (4) are consistent with steps (2) to (4) of Comparative Example 1.

[0066] Comparative Example 3

[0067] (1) Potassium hydroxide solid powder, sodium hydroxide solid powder and hydrated sodium silicate solution are mixed by mechanical stirring at a stirring speed of 300 r / min. The amount of sodium hydroxide solid powder added is 15 parts, the amount of potassium hydroxide solid powder added is 10 parts, and the amount of hydrated sodium silicate solution added is 100 parts. The mass content of sodium silicate in the hydrated sodium silicate solution is 38.0%. After mixing, a milky white compound activator is obtained. Then, the compound activator is ultrasonically activated by an ultrasonic oscillator with an ultrasonic power of 300 W, an ultrasonic frequency of 40 kHz and an ultrasonic time of 120 seconds to obtain a clear and transparent mixed curing agent.

[0068] Step (2) The lithium slag and blast furnace slag are ground and sieved separately. The lithium slag and blast furnace slag used are the same as in Example 1. The ground lithium slag is sieved through a 200-mesh sieve (<75μm) to obtain lithium slag with an average particle size of 25μm as graded lithium slag. The ground blast furnace slag is sieved through a 400-mesh sieve (<38μm) to obtain slag with an average particle size of 13μm as graded blast furnace slag.

[0069] Step (3) Mix the mixed curing agent, graded lithium slag, and graded blast furnace slag thoroughly by high-speed mechanical stirring at a speed of 300 r / min. By mass, the amount of mixed curing agent added is 50 parts, the amount of graded lithium slag added is 70 parts, and the amount of graded blast furnace slag added is 30 parts, to obtain the curing precursor.

[0070] Step (4) is the same as step (4) in Comparative Example 2.

[0071] Comparative Example 4

[0072] Steps (1) to (2) are consistent with steps (1) to (2) of Comparative Example 3.

[0073] Step (3) The mixed curing agent, graded lithium slag, and graded blast furnace slag are thoroughly mixed by high-speed mechanical stirring at a stirring speed of 300 r / min. By mass, the amount of mixed curing agent added is 50 parts, the amount of graded lithium slag added is 70 parts, and the amount of graded blast furnace slag added is 30 parts to obtain a mixed slurry. Then, the mixed slurry is subjected to two-stage ultrasonic excitation using an ultrasonic oscillator with an ultrasonic power of 200 W, an ultrasonic frequency of 40 kHz, and an ultrasonic time of 60 seconds to obtain a curing precursor.

[0074] Step (4) is the same as step (4) in Comparative Example 3.

[0075] Comparative Example 5

[0076] Step (1) is the same as step (1) in Example 1.

[0077] Step (2) The lithium slag and blast furnace slag are ground and sieved respectively. The ground lithium slag and the ground blast furnace slag are sieved through a 200-mesh sieve (<75μm) to obtain lithium slag with an average particle size of 25μm as graded lithium slag and blast furnace slag with an average particle size of 25μm as graded blast furnace slag.

[0078] Steps (3) to (4) are consistent with steps (3) to (4) of Example 1.

[0079] Comparative Example 6

[0080] Step (1) is the same as step (1) in Example 1.

[0081] Step (2) The lithium slag and blast furnace slag are ground and sieved respectively. The ground lithium slag and the ground blast furnace slag are sieved through a 400-mesh sieve (<38μm) to obtain lithium slag with an average particle size of 13μm as graded lithium slag and blast furnace slag with an average particle size of 13μm as graded blast furnace slag.

[0082] Steps (3) to (4) are consistent with steps (3) to (4) of Example 1.

[0083] Test case

[0084] The cured molding materials of the examples and comparative examples were subjected to leaching experiments and mechanical strength tests in different simulated environments.

[0085] Following the standard "Solid Waste Leaching Toxicity Leaching Method: Sulfuric Acid and Nitric Acid Method (HJ / T 299-2007)," an acidic precipitation environment was simulated. The cured materials from Comparative Examples 1-4 and Examples 1-3 were tested according to standard requirements. The heavy metal leaching concentration and curing rate were as follows: Figure 2 As shown. By Figure 2 It can be seen that the embodiments of the present invention effectively improve the heavy metal solidification effect through the first, second, and third ultrasonic processes. The lithium slag and blast furnace slag gradation process and the alkali compounding process also improve the heavy metal solidification effect, significantly enhancing the stability of the solidified material in the simulated acidic precipitation environment. Taking Example 1 as an example, Example 1 achieves simultaneous and effective solidification of multiple heavy metals in waste slag. The leaching of thallium, niobium, tantalum, lead, chromium, copper, and zinc are all significantly improved, with the heavy metal leaching concentration below 40.15 μg / L. The solidification rate of the seven heavy metals is distributed between 99.00% and 99.99% (e.g., ...). Figure 2 and Figure 3 As shown in the figure, it meets the standard requirements for leaching concentrations of different heavy metals in the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification (GB 5085.3-2007)". It can be seen that the solidification and stabilization effect of the embodiments of the present invention on multiple metals is significantly better than that of the comparative examples.

[0086] The leaching concentrations and solidification rates of various heavy metals in Examples 1-3 were obtained under simulated acid, alkali, salt, and high-salt environments, as well as under the influence of landfill leachate simulated according to the "Solid Waste Leaching Toxicity Leaching Method Acetic Acid Buffer Solution Method (HJ / T 300-2007)". Figure 4 and Figure 5 As shown, the embodiments of the present invention can keep different heavy metals stable under different environmental conditions, thereby effectively solidifying the heavy metals in waste residue.

[0087] Figure 6 The mechanical strength of the cured materials in Examples 1-3 and Comparative Examples 1-4 was measured. The compressive strength of the cured materials was tested using the method described in "Test Method for Strength of Cement Mortar (ISO Method)" (GB / T 17671-2021). Comparison of the mechanical strength of the comparative examples and the examples shows that after the first, second, and third ultrasonic processes, the lithium slag and blast furnace slag gradation process, and the alkali compounding process, the mechanical strength of the examples, consistent with the changes in heavy metal curing effect, exhibits a significant upward trend. The stability of the heavy metal curing performance and mechanical properties is consistent. The compressive strengths of Examples 1, 2, and 3 reached 34.88 MPa, 27.52 MPa, and 30.05 MPa, respectively, meeting the requirements of most application scenarios and ensuring the application range of lithium slag and blast furnace slag derivative products.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the substantive technical content of the present invention. The substantive technical content of the present invention is broadly defined within the scope of the claims. Any technical entity or method implemented by others that is completely identical to or an equivalent modification of the claims is considered to be covered within the scope of the claims.

Claims

1. A method for synergistic enhancement of heavy metal solidification in lithium slag using multi-segment ultrasound and gradation, comprising the following steps: (1) The hydroxide and silicate are mixed and activated by a period of ultrasound to obtain a mixed curing agent; (2) Grind and sieve the lithium slag and blast furnace slag separately, and then perform particle size distribution on the lithium slag and blast furnace slag to obtain the graded lithium slag and the graded blast furnace slag. (3) The mixed curing agent, the graded lithium slag and the graded blast furnace slag are mixed and excited by two-stage ultrasound to obtain a curing precursor; (4) The cured precursor is injected into the mold, strengthened by three-stage ultrasound, then sealed and cured, and then demolded to obtain the cured molding material.

2. The method for multi-segment ultrasonic and gradation-synergistic enhancement of heavy metal solidification in lithium slag according to claim 1, wherein, In step (1), the hydroxide includes sodium hydroxide and potassium hydroxide; the silicate includes a hydrated sodium silicate solution.

3. The method for multi-segment ultrasonic and gradation-synergistic enhancement of heavy metal solidification in lithium slag according to claim 2, wherein, In step (1), the sodium silicate content in the hydrated sodium silicate solution is 35.4%~41.0% by mass; And / or, in step (1), the amount of sodium hydroxide added is 10 to 25 parts by mass, the amount of potassium hydroxide added is 5 to 15 parts, and the amount of hydrated sodium silicate solution added is 80 to 100 parts.

4. The method for multi-segment ultrasonic and gradation-synergistic enhancement of heavy metal solidification in lithium slag according to claim 1, wherein, In step (1), the ultrasonic power of the ultrasonic segment is 200~300W, the ultrasonic frequency is 40~50kHz, and the ultrasonic time is 60~120 seconds.

5. The method for multi-segment ultrasonic and gradation-synergistic enhancement of heavy metal solidification in lithium slag according to claim 1, wherein, In step (2), 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%; And / or, in step (2), based on the total mass of the blast furnace slag as 100%, it includes: CaO 36.0%~44.0%, SiO2 30.0%~36.0%, Al2O3 8.0%~16.0% and MgO 4.0%~13.0%.

6. The method for multi-segment ultrasonic and gradation-synergistic enhancement of heavy metal solidification in lithium slag according to claim 1, wherein, In step (2), the lithium slag and blast furnace slag are ground separately. The ground lithium slag is passed through a 200-mesh sieve to obtain lithium slag with an average particle size of 1~25μm as graded lithium slag. The ground blast furnace slag is passed through a 400-mesh sieve to obtain blast furnace slag with an average particle size of 1~13μm as graded blast furnace slag.

7. The method for multi-segment ultrasonic and gradation-synergistic enhancement of heavy metal solidification in lithium slag according to claim 1, wherein, In step (3), based on the total amount of 100 parts by weight of the graded lithium slag and the graded blast furnace slag, the amount of the mixed solidifying agent added is 50 to 70 parts. And / or, by mass, based on the total amount of 100 parts of the graded lithium slag and the graded blast furnace slag, the amount of graded lithium slag added is 70-90 parts, and the amount of graded blast furnace slag added is 10-30 parts.

8. The method for multi-segment ultrasonic and gradation-synergistic enhancement of heavy metal solidification in lithium slag according to claim 1, wherein, In step (3), the ultrasonic power of the two-segment ultrasound is 200~300W, the ultrasonic frequency is 40~50kHz, and the ultrasonic time is 60~120 seconds. And / or, in step (3), the mixed curing agent, the graded lithium slag and the graded blast furnace slag are mixed by mechanical stirring at a speed of 200~400 r / min, and then excited by two-stage ultrasound to obtain the curing precursor.

9. The method for multi-segment ultrasonic and gradation synergistic enhancement of heavy metal solidification in lithium slag according to claim 1, wherein, In step (4), the ultrasonic power of the three ultrasonic segments is 200~300W, the ultrasonic frequency is 40~50kHz, and the ultrasonic time is 60~120 seconds; And / or, in step (4), the cured precursor is injected into the mold, the cured precursor is stirred by an ultrasonic vibrating rod at a speed of 100~200 r / min, and is strengthened by three-stage ultrasound, then sealed and cured, and then demolded to obtain the cured molding material.

10. The method for multi-segment ultrasonic and gradation-synergistic enhancement of heavy metal solidification in lithium slag according to claim 1, wherein, In step (4), the temperature for sealing and curing is 60~90℃ and the time is 1.0~4.0h.

11. A curing molding material, which is prepared by the multi-segment ultrasonic and gradation synergistic strengthening method for curing heavy metals in lithium slag according to any one of claims 1-10.

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