Method for solidifying lepidolite tailing slag through cooperation with fly ash under assistance of multi-stage ultrasonic heat and lepidolite tailing slag solidification derivative material

Abstract

The invention discloses a method for solidifying lepidolite tailings through cooperation with fly ash under assistance of multi-stage ultrasonic heat and a derivative material for solidifying the lepidolite tailings, and belongs to the technical field of harmless and resourceful treatment of soil bodies and gravel materials. The method comprises the following steps: performing first-stage heat assistance and first-stage ultrasonic treatment on nano silicon dioxide, hydroxide and silicate to obtain a compound activator; carrying out second-stage heat assistance and second-stage ultrasonic treatment on the compound exciting agent and fly ash to obtain a mixed curing agent; mixing the mixed curing agent with the lepidolite tailings, and carrying out third-section heat assistance to obtain mixed slurry; the mixed slurry is subjected to injection molding under fourth-section heat assistance, then third-section ultrasonic treatment is conducted, then sealed curing and fifth-section heat assistance are conducted, demolding is conducted, and the lepidolite tailing slag curing derivative material is obtained. According to the method, the solidification of heavy metals in the lepidolite tailings can be enhanced in a manner of multi-section ultrasonic heat-assisted cooperation with the fly ash, and harmlessness, stabilization and recycling of the lepidolite tailings are realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of harmless and resourceful treatment of soil and sandstone, and particularly relates to a method for solidifying lithium mica tailings with multiple ultrasonic heat assistance and fly ash and a lithium mica tailings solidified derivative material. BACKGROUND

[0002] Lithium mineral resources, as the cornerstone of the development of electric vehicles, have become the key to the development of the new energy vehicle industry. Lithium mica tailings are mainly composed of gypsum (CaSO4·2H2O), quartz, analcime, muscovite, kaolinite and other substances, and are one of the most common lithium-containing minerals on earth. A large amount of waste slag is generated during its mining and refining process, which contains metal elements such as thallium (Tl), niobium (Nb), tantalum (Ta), lead (Pb), chromium (Cr), copper (Cu), and zinc (Zn). If directly stacked and treated, there is a serious leaching risk, and these high-value metal resources will be wasted. Therefore, it is urgent to provide a low-cost, safe and reliable method for solidifying and stabilizing lithium mica tailings.

[0003] Traditional solidification methods often require a large amount of cement, lime and other solidifying agents to embed hazardous waste in its structure through physical or chemical reactions to achieve solidification / stabilization. However, this method is easily affected by natural environmental factors (such as temperature, humidity, pH, etc.) leading to a decline in the performance of the solidified body or the release of harmful substances, and wastes a large amount of silicon (Si), aluminum (Al), iron (Fe), calcium (Ca) and other elements contained in the slag that can form a stable cementitious structure.

[0004] Alkali activation can cross-link hydrated silicates, hydrated silico-aluminates and other products contained in the slag to form geopolymer cement with a stable three-dimensional network structure, which is an ideal method for solidifying slag. However, the catalytic effect of alkali activator on slag hydration will slow down or basically terminate over time. Newly generated minerals (such as silico-aluminate gel) may also adhere to the surface of fine slag particles, blocking the path of active ion reaction, leading to a slow reaction and affecting the performance of alkali-activated cementitious materials. How to strengthen the alkali-activated solidification method of lithium mica tailings to improve the solidification stability of heavy metals in lithium mica tailings has become one of the problems to be solved in the field. SUMMARY

[0005] To solve the above technical problems, the purpose of the present application is to provide a method for solidifying lithium mica tailings with multiple ultrasonic heat assistance and fly ash and a lithium mica tailings solidified derivative material. The present application can strengthen the solidification of heavy metals in lithium mica tailings, improve the solidification stability of heavy metals in lithium mica tailings, and produce lithium mica tailings solidified derivative materials, thereby realizing the harmless, stable and resourceful treatment of lithium mica tailings.

[0006] To achieve the above object, the present application provides a method for solidifying lepidolite tailings with fly ash under multi-stage ultrasonic heat assistance, which comprises the following steps:

[0007] (1) A complex activator is prepared by adding nano-silica, hydroxide and silicate selectively, and through first-stage heat assistance and first-stage ultrasonic treatment;

[0008] (2) A mixed curing agent is prepared by using the complex activator and fly ash, and through second-stage heat assistance and second-stage ultrasonic treatment;

[0009] (3) The mixed curing agent is mixed with lepidolite tailings, and a mixed slurry is obtained through third-stage heat assistance;

[0010] (4) The mixed slurry is injected into a mold under fourth-stage heat assistance, and then subjected to third-stage ultrasonic treatment, sealed and cured, and subjected to fifth-stage heat assistance, and finally demolded, so as to obtain a lepidolite tailings solidified derivative material and complete the solidification of the lepidolite tailings.

[0011] According to the specific embodiments of the present application, preferably, in step (1), the hydroxide is sodium hydroxide and potassium hydroxide.

[0012] According to the specific embodiments of the present application, preferably, in step (1), the silicate is hydrated sodium silicate.

[0013] According to the specific embodiments of the present application, preferably, in step (1), the total mass of the complex activator is 100%, the addition amount of nano-silica is 0-15%, the addition amount of sodium hydroxide is 10-20%, the addition amount of potassium hydroxide is 10-20%, and the addition amount of hydrated sodium silicate is 60-80%. More preferably, the total mass of the complex activator is 100%, the addition amount of nano-silica is 5-15%, the addition amount of sodium hydroxide is 10-20%, the addition amount of potassium hydroxide is 10-20%, and the addition amount of hydrated sodium silicate is 60-75%.

[0014] According to the specific embodiments of the present application, preferably, in step (1), the hydrated sodium silicate is a hydrated sodium silicate liquid, and the mass content of sodium silicate therein is 20-30%, for example, 26.7%.

[0015] According to the specific embodiments of the present application, preferably, in step (1), the particle size of the nano-silica is 1-100 nm.

[0016] According to the specific embodiment of the present application, preferably, in step (1), the temperature of the first heat assistance is 60-80℃; the ultrasonic power of the first ultrasonic is 250-350W, the ultrasonic frequency is 40-60kHz, and the ultrasonic time is 5-15min.

[0017] According to the specific embodiment of the present application, preferably, in step (1), the complex excitation agent is prepared by the first mechanical stirring, the first heat assistance and the first ultrasonic, using the selectively added nano-silica, and the hydroxide and silicate.

[0018] In step (1) of the present application, the nano-silica, sodium hydroxide and potassium hydroxide are prepared into a mixed powder with the above-mentioned dosing amount; then the mixed powder is added into the sodium silicate hydrate liquid for one-time feeding, and the mechanical stirrer is used for mechanical stirring; the mixture is heated and controlled at constant temperature during the stirring, so as to perform the first heat assistance; by controlling the temperature of the first heat assistance in the above-mentioned range, it is beneficial to ensure the full activation of each component; and after uniform stirring, the ultrasonic oscillation equipment is used for the first ultrasonic; by controlling the conditions of the first ultrasonic in the above-mentioned range, it is beneficial to fully mix, dissolve and activate each component until there is no obvious particulate matter, so as to obtain the complex excitation agent in a viscous liquid state.

[0019] According to the specific embodiment of the present application, preferably, in step (2), the dosing amount of the complex excitation agent is 70-90% and the dosing amount of the fly ash is 10-30%, based on 100% of the total mass of the mixed curing agent.

[0020] According to the specific embodiment of the present application, preferably, in step (2), based on 100% of the total mass of the fly ash, it includes 40-45% of SiO2, 40-45% of Al2O3, 4-8% of Fe2O3, 2-4% of CaO, 2-4% of TiO2 and other trace substances. For example, based on 100% of the total mass of the fly ash, it includes 43.8% of SiO2, 40.9% of Al2O3, 5.9% of Fe2O3, 2.8% of CaO, 2.7% of TiO2 and other trace substances. The present application does not specially limit the specific types of other trace substances.

[0021] According to the specific embodiment of the present application, preferably, in step (2), the temperature of the second heat assistance is 60-80℃; the ultrasonic power of the second ultrasonic is 250-350W, the ultrasonic frequency is 40-60kHz, and the ultrasonic time is 5-15min.

[0022] According to the specific embodiment of the present application, preferably, in step (2), the mixed curing agent is prepared by mixing the compound activator and fly ash, through second mechanical stirring, second stage heat assistance and second stage ultrasonic.

[0023] In step (2) of the present application, preferably, fly ash is added to the compound activator for secondary feeding, and second stage ultrasonic is performed under the synergistic action of a mechanical stirrer and ultrasonic oscillation equipment in a constant temperature control condition, and second stage heat assistance is performed. By controlling the conditions of second stage heat assistance, second stage ultrasonic and mechanical stirring in the above range, it is beneficial to ensure that the fly ash and the compound activator are fully mixed and react, thereby forming a liquid mixed curing agent.

[0024] According to the specific embodiment of the present application, preferably, in step (3), the mass ratio of the mixed curing agent to the lithium mica tailings slag is (3:1) to (4:1).

[0025] According to the specific embodiment of the present application, preferably, in step (3), the lithium mica tailings slag includes 30-40% of Al2O3, 20-30% of Fe2O3, 15-25% of CaO, 10-15% of SiO2 and other trace substances, based on the total mass of the lithium mica tailings slag being 100%. For example, the lithium mica tailings slag includes 37.92% of Al2O3, 26.59% of Fe2O3, 18.8% of CaO, 13.8% of SiO2 and other trace substances, based on the total mass of the lithium mica tailings slag being 100%. The present application does not specially limit the specific types of other trace substances.

[0026] According to the specific embodiment of the present application, preferably, in step (3), the mixed curing agent and the lithium mica tailings slag are mixed, and the mixed slurry is obtained through third stage heat assistance and third mechanical stirring. The temperature of the third stage heat assistance is 60-80°C. The rotating speed of the third mechanical stirring is 250-450 rpm.

[0027] In step (3) of the present application, preferably, the lithium mica tailings slag is added to the mixed curing agent, and the structure of the lithium mica tailings slag is fully dispersed and completely wrapped in the mixed curing agent under constant temperature heating and continuous mechanical stirring. By controlling the conditions of third stage heat assistance and mechanical stirring in the above range, it is beneficial to make the lithium mica tailings slag and the mixed curing agent fully contact and react, thereby forming a mixed slurry that is uniform and consistent without significant particle separation.

[0028] According to the specific embodiment of the present application, preferably, in step (4), the temperature of the fourth stage of heat assistance is 60-80℃; the ultrasonic power of the third stage of ultrasonic is 250-350W, the ultrasonic frequency is 40-60kHz, and the ultrasonic time is 5-15min; the time of the sealing curing is 3-10d; and the temperature of the fifth stage of heat assistance is 60-80℃.

[0029] In step (4) of the present application, the fourth stage of heat assistance is performed in the mixed slurry injection molding stage, and the third stage of ultrasonic is performed after the mixed slurry is injected into the mold, which is beneficial to expel the gas in the mixed slurry as much as possible, avoid the formation of structural defects such as pores, and increase the continuity of the structure, thereby being beneficial to improve the compactness and uniformity of the lithium mica tailings slag solidified derived material. Then, the mixed slurry is sealed and placed in a curing box for the fifth stage of heating and constant temperature heat assistance curing, thereby being beneficial to improve the mechanical strength and other properties of the lithium mica tailings slag solidified derived material. After the mixed slurry is formed, the formed material obtained is the lithium mica tailings slag solidified derived material of the present application.

[0030] The second aspect of the present application improves a lithium mica tailings slag solidified derived material, which is prepared by the above-mentioned multi-stage ultrasonic heat assistance and cooperated with fly ash lithium mica tailings slag solidification method.

[0031] According to the specific embodiment of the present application, preferably, the compressive strength of the lithium mica tailings slag solidified derived material after 7d curing is 24-30MPa.

[0032] According to the specific embodiment of the present application, preferably, the solidification rate of the heavy metals in the lithium mica tailings slag solidified derived material is 98.95%-100%. The solidification rate is tested according to the method recorded in HJ / T 299-2007. Specifically, the heavy metals include one or more than two of chromium, copper, zinc, niobium, tantalum, thallium and lead; more specifically, the heavy metals include chromium, zinc, niobium, tantalum, thallium and lead.

[0033] The present application utilizes the abundant aluminum, silicon, calcium and other elements of lithium mica tailings slag itself, simultaneously solidifies the heavy metals in the lithium mica tailings slag, especially the seven metals of chromium, copper, zinc, niobium, tantalum, thallium and lead, synthesizes a derived material with high strength, and realizes the harmless, stabilization and resource utilization of the lithium mica tailings slag.

[0034] And, the present application adopts multi-stage ultrasonic strengthening in the preparation stage of the compound activator, the preparation stage of the mixed curing agent and the exhaust stage after injection molding, respectively, which significantly promotes the dissolution and reaction of the slag, increases the content of active silicon and aluminum ions in the reaction system, and at the same time, destroys the small attachments on the surface of the particles, dredges the path of the active ion reaction, which is conducive to the full hydration reaction, so as to form a more compact silicate gel structure, and the ultrasonic after injection molding can also increase the continuity of the structure, which is conducive to improving the compactness and uniformity of the derived material, thereby improving the curing rate and mechanical strength of the derived material.

[0035] Moreover, the present application adopts multi-stage heating and insulation assistance in the preparation stage of the compound activator, the preparation stage of the mixed curing agent, the lithium mica tailing slag curing stage, the slurry injection molding stage and the sealing and curing stage, which helps to reduce the activation energy of the reaction, fully activates the components in each stage, and provides sufficient energy for the alkali activation reaction, which is conducive to reducing the microstructure defects in the derived material, such as pores and cracks, thereby improving the curing rate and mechanical strength of the derived material.

[0036] The multi-stage ultrasonic and thermal assistance strengthening method of the present application can promote the formation and hardening of silicate gel and other products, improve the mechanical strength of the derived material, and also improve the durability of the material, such as freeze-thaw resistance and sulfate corrosion resistance.

[0037] At the same time, the fly ash in the mixed curing agent of the present application can be filled between the lithium mica tailing slag particles, improving the particle gradation and improving the compactness of the derived material. Moreover, the glass beads in the fly ash can play a ball bearing effect between the lithium mica tailing slag particles, reducing the friction between the particles, which is conducive to uniform mixing and makes the derived material more compact. At the same time, the active SiO2 and Al2O3 in the fly ash are used for alkali activation reaction to form more three-dimensional network structure. Therefore, the use of fly ash in the present application is conducive to improving the curing rate and mechanical strength of the derived material.

[0038] The present application has at least the following beneficial effects:

[0039] The application adopts a mixed solidifying agent prepared by a basic compound activator and fly ash, and solidifies and stabilizes various heavy metals in lithium mica tailings through a multi-stage ultrasonic heat-assisted mode, and derives a material with excellent mechanical strength through processes such as slurry mixing, mold injection, exhaust, curing and the like. The application strengthens the solidification of the heavy metals in the lithium mica tailings through the multi-stage ultrasonic heat-assisted mode in cooperation with the fly ash, improves the solidification stability of the heavy metals in the lithium mica tailings, has a high heavy metal solidification rate, and stably fixes the heavy metals in the lithium mica tailings in different environmental conditions such as acid, alkali, salt and high salt. Meanwhile, the application produces a lithium mica tailings solidified derived material and improves the mechanical strength of the derived material. Therefore, the application realizes the harmless treatment, stabilization and resource utilization of the lithium mica tailings. The application realizes the synchronous solidification of various heavy metals in the lithium mica tailings through a process with a short flow, low cost, low carbon emission, small environmental risk and strong operability, has the advantages of low construction cost, high safety, small secondary pollution, convenient automatic control and the like, and generates a derived material with high mechanical strength, and the derived product is reliable. The application is beneficial to the harmless treatment, resource utilization of bulk solid waste and the research and development of related functional materials, conforms to the concept of circular economy, and provides a new way for the research and development and production of industrial by-products and environment-friendly materials. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 It is a flowchart of the lithium mica tailings solidification method under the multi-stage ultrasonic heat-assisted mode in cooperation with fly ash in the specific embodiments of the application.

[0041] Figure 2 It is the test result of the leaching concentration and solidification rate of the heavy metals in the lithium mica tailings according to the method and conditions in HJ / T 299-2007 in the comparative example.

[0042] Figure 3 It is the test result of the solidification rate distribution of the heavy metals in the lithium mica tailings according to the method and conditions in HJ / T 299-2007 in the comparative example.

[0043] Figure 4 It is the change and loss rate of the mass and compressive strength of the lithium mica tailings in the freeze-thaw cycle experiment in the comparative example.

[0044] Figure 5 It is the test result of the leaching concentration and solidification rate of the heavy metals in the lithium mica tailings according to the method and conditions in HJ / T 299-2007 in the example.

[0045] Figure 6 It is the test result of the solidification rate distribution of the heavy metals in the lithium mica tailings according to the method and conditions in HJ / T 299-2007 in the example.

[0046] Figure 7 The change and loss rate of quality and compressive strength in the anti-freeze-thaw cycle experiment for the embodiment. DETAILED DESCRIPTION

[0047] In order to have a more clear understanding of the technical features, objectives and beneficial effects of the present application, the present application will be described in detail below, but it should not be understood as limiting the scope of the present application.

[0048] It should be noted that, unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0049] Unless otherwise specified, all kinds of raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0050] It should be understood that the terms "include", "contain" and / or "comprise" 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.

[0051] The endpoints of the ranges and any values disclosed in the present application are not limited to the precise values or the exact ranges, and these ranges should be understood to encompass values approximately around these ranges. For numerical ranges, the endpoints of each range, the endpoints of each range 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 the present application.

[0052] In the detailed description of the present application, as shown in Figure 1 The method for solidifying lithium mica tailings with multi-stage ultrasonic heat assistance and fly ash according to the present application comprises the following steps:

[0053] (1) Mix nano-silicon dioxide, sodium hydroxide, potassium hydroxide and hydrated sodium silicate liquid and perform mechanical stirring, the stirring speed is 250-450 rpm, the mass content of sodium silicate in the hydrated sodium silicate liquid is 20-30%, heat to 60-80°C and keep, thereby performing first-stage heat assistance, after uniform stirring, perform first-stage ultrasonic, the ultrasonic power is 250-350 W, the ultrasonic frequency is 40-60 kHz, the ultrasonic time is 5-15 min, thereby preparing a compounded activator; taking the total mass of the compounded activator as 100%, the addition amount of nano-silicon dioxide is 5-15%, the addition amount of sodium hydroxide is 10-20%, the addition amount of potassium hydroxide is 10-20%, and the addition amount of hydrated sodium silicate liquid is 60-75%;

[0054] (2) mixing fly ash and compound activator and mechanical stirring, stirring speed is 250~450 rpm, and heated to 60~80℃ and keep, so as to carry out the second stage of heat assisted, after stirring evenly, the second stage of ultrasonic, ultrasonic power is 250~350 W, ultrasonic frequency 40~60 kHz, ultrasonic time is 5~15 min, the mixed curing agent is prepared; the total mass of fly ash is 100%, including 40~45% of SiO2, 40~45% of Al2O3, 4~8% of Fe2O3, 2~4% of CaO, 2~4% of TiO2 and other trace substances; the total mass of mixed curing agent is 100%, the dosage of compound activator is 70~90%, the dosage of solid fly ash is 10~30%;

[0055] (3) mixing lithium mica tailings with mixed curing agent and mechanical stirring, the mixed curing agent and lithium mica tailings mixed mass ratio is (3:1)~(4:1), stirring speed is 250~450 rpm, and heated to 60~80℃ and keep until pouring into the mold, so as to carry out the third stage of heat assisted, get mixed slurry; the total mass of lithium mica tailings is 100%, including 30~40% of Al2O3, 20~30% of Fe2O3, 15~25% of CaO, 10~15% of SiO2 and other trace substances;

[0056] (4) the mixed slurry kept at 60~80℃ is poured into the mold, then the third stage of ultrasonic is carried out, ultrasonic power is 250~350 W, ultrasonic frequency 40~60 kHz, ultrasonic time is 5~15 min, so that the gas is completely discharged, then the mixed slurry is sealed, and then put into the curing box for heating and constant temperature curing, so as to realize the fifth stage of heat assisted, the temperature of heating and constant temperature curing is 60~80℃, the curing time is 3~10 d (days), then demoulding, the lithium mica tailings solidified derived material is prepared, and the solidification of lithium mica tailings is completed.

[0057] Example 1

[0058] (1) Nano-silica (particle size 1~100nm), sodium hydroxide solid powder and potassium hydroxide solid powder are mixed to obtain a mixed powder; the mixed powder is added to hydrated sodium silicate liquid and mechanically stirred at a stirring speed of 400rpm. The mass content of sodium silicate in the hydrated sodium silicate liquid is 26.7%. The mixture is heated to 80℃ within 10min and maintained to perform the first stage of heat assistance. After stirring evenly, the first stage of ultrasound is performed with an ultrasound power of 350W, an ultrasound frequency of 50kHz and an ultrasound time of 10min to prepare a compound activator; based on the total mass of the compound activator as 100%, the amount of nano-silica added is 5%, the amount of sodium hydroxide solid powder added is 10%, the amount of potassium hydroxide solid powder added is 10%, and the amount of hydrated sodium silicate liquid added is 75%.

[0059] (2) Solid fly ash is added to the compound activator and mechanically stirred at a speed of 400 rpm. The mixture is heated to 80°C within 10 min and maintained for the second stage of heat assistance. After stirring evenly, the second stage of ultrasound is performed with an ultrasound power of 350 W, an ultrasound frequency of 50 kHz, and an ultrasound time of 10 min to prepare a liquid mixed curing agent. Based on the total mass of solid fly ash of 100%, it includes 43.8% SiO2, 40.9% Al2O3, 5.9% Fe2O3, 2.8% CaO, 2.7% TiO2, and other trace substances as the remainder. Based on the total mass of liquid mixed curing agent of 100%, the amount of compound activator added is 90%, and the amount of solid fly ash added is 10%.

[0060] (3) Add the lithium mica tailings to the liquid mixed curing agent and mechanically stir. The mixing mass ratio of lithium mica tailings to liquid mixed curing agent is 3:1. The stirring speed is 400 rpm. Heat to 80°C within 10 min and maintain until injected into the mold, thereby performing the third stage of heat assistance, so that the lithium mica tailings and liquid mixed curing agent can fully contact and react to obtain a uniform mixed slurry. The total mass of lithium mica tailings is 100%, which includes 37.92% Al2O3, 26.59% Fe2O3, 18.8% CaO, 13.8% SiO2 and other trace substances as the balance.

[0061] (4) The mixed slurry, kept at 80°C, is injected into the mold. Then, the third stage of ultrasound is performed. The ultrasound power is 350W, the ultrasound frequency is 50kHz, and the ultrasound time is 10min. The gas is completely discharged. Then, the mixed slurry is sealed and placed in the curing box for heating and constant temperature curing, thereby realizing the fifth stage of heat assistance. The heating and constant temperature curing temperature is 80°C and the curing time is 7d. After demolding, the lithium mica tailings slag solidified derivative material is prepared and the solidification of lithium mica tailings slag is completed.

[0062] Example 2

[0063] This embodiment is basically the same as embodiment 1, except that the amount of fly ash added in step (2) is different. Taking the total mass of the liquid mixed curing agent as 100%, the amount of compound activator added is 80% and the amount of solid fly ash added is 20%.

[0064] Example 3

[0065] This embodiment is basically the same as embodiment 1, except that the amount of fly ash added in step (2) is different. Taking the total mass of the liquid mixed curing agent as 100%, the amount of compound activator added is 70% and the amount of solid fly ash added is 30%.

[0066] Example 4

[0067] This embodiment is basically the same as embodiment 1, except that the frequency and power of ultrasound in steps (1), (2), and (4) are different. In this embodiment, the ultrasound power in steps (1), (2), and (4) is 250W and the ultrasound frequency is 40kHz.

[0068] Example 5

[0069] This embodiment is basically the same as embodiment 1, except that the temperature of the heat-assisted step (1), (2), (3), (4) is different. The temperature of the heat-assisted step (1), (2), (3), (4) in this embodiment is 60°C.

[0070] Example 6

[0071] This embodiment is basically the same as embodiment 1, except that the dosage of lithium mica tailings and liquid mixed curing agent in step (3) is different, and the mixing mass ratio of lithium mica tailings and liquid mixed curing agent is 4:1.

[0072] Comparative Example 1

[0073] (1) Sodium hydroxide solid powder and potassium hydroxide solid powder are mixed to obtain a mixed powder; the mixed powder is added to hydrated sodium silicate liquid and mechanically stirred at a stirring speed of 400 rpm. The mass content of sodium silicate in the hydrated sodium silicate liquid is 26.7%. After stirring evenly, a compound activator is prepared; based on the total mass of the compound activator as 100%, the amount of sodium hydroxide solid powder added is 10%, the amount of potassium hydroxide solid powder added is 10%, and the amount of hydrated sodium silicate liquid added is 80%.

[0074] (2) Solid fly ash is added to the compound activator and mechanically stirred at a speed of 400 rpm to prepare a liquid mixed curing agent. Based on the total mass of solid fly ash as 100%, it includes 43.8% SiO2, 40.9% Al2O3, 5.9% Fe2O3, 2.8% CaO, 2.7% TiO2 and other trace substances as the balance. Based on the total mass of liquid mixed curing agent as 100%, the amount of compound activator added is 90% and the amount of solid fly ash added is 10%.

[0075] (3) Add the lithium mica tailings to the liquid mixed curing agent and stir mechanically. The mixing mass ratio of lithium mica tailings to liquid mixed curing agent is 3:1, and the stirring speed is 400 rpm to obtain a mixed slurry. The total mass of lithium mica tailings is 100%, which includes 37.92% Al2O3, 26.59% Fe2O3, 18.8% CaO, 13.8% SiO2 and other trace substances.

[0076] (4) The mixed slurry is injected into the mold, then the mixed slurry is sealed and placed in the curing box for heating and constant temperature curing, so as to achieve heat assistance. The heating and constant temperature curing temperature is 80℃ and the curing time is 7 days. After demolding, the lithium mica tailings solidified derivative material is prepared and the solidification of lithium mica tailings is completed.

[0077] Comparative Example 2

[0078] (1) Mix nano-silica (particle size of 1~100nm), sodium hydroxide solid powder and potassium hydroxide solid powder to obtain a mixed powder; add the mixed powder to hydrated sodium silicate liquid and mechanically stir at a stirring speed of 400rpm. The mass content of sodium silicate in the hydrated sodium silicate liquid is 26.7%. After stirring evenly, a compound activator is prepared. Based on the total mass of the compound activator as 100%, the amount of nano-silica added is 5%, the amount of sodium hydroxide solid powder added is 10%, the amount of potassium hydroxide solid powder added is 10%, and the amount of hydrated sodium silicate liquid added is 75%.

[0079] Steps (2) to (4) are consistent with steps (2) to (4) of Comparative Example 1.

[0080] Comparative Example 3

[0081] (1) Nano-silica (particle size 1~100nm), sodium hydroxide solid powder and potassium hydroxide solid powder are mixed to obtain a mixed powder; the mixed powder is added to hydrated sodium silicate liquid and mechanically stirred at a stirring speed of 400rpm. The mass content of sodium silicate in the hydrated sodium silicate liquid is 26.7%. The mixture is heated to 80℃ within 10min and maintained for thermal assistance. After stirring evenly, it is ultrasonicated at a power of 350W, a frequency of 50kHz and a duration of 10min to prepare a compound activator; based on the total mass of the compound activator as 100%, the amount of nano-silica added is 5%, the amount of sodium hydroxide solid powder added is 10%, the amount of potassium hydroxide solid powder added is 10%, and the amount of hydrated sodium silicate liquid added is 75%.

[0082] Steps (2) to (4) are consistent with steps (2) to (4) of Comparative Example 2.

[0083] Comparative Example 4

[0084] Steps (1) to (2) are consistent with steps (1) to (2) of Comparative Example 3.

[0085] (3) Add the lithium mica tailings to the liquid mixed curing agent and mechanically stir. The mixing mass ratio of lithium mica tailings to liquid mixed curing agent is 3:1. The stirring speed is 400 rpm. Heat to 80°C within 10 min and maintain until injected into the mold, thereby performing the third stage of heat assistance, so that the lithium mica tailings and liquid mixed curing agent can fully contact and react to obtain a uniform mixed slurry. The total mass of lithium mica tailings is 100%, which includes 37.92% Al2O3, 26.59% Fe2O3, 18.8% CaO, 13.8% SiO2 and other trace substances as the balance.

[0086] (4) The mixed slurry, which is kept at 80°C, is injected into the mold. The mixed slurry is then sealed and placed in a curing box for heating and constant temperature curing, thereby achieving heat assistance. The heating and constant temperature curing temperature is 80°C and the curing time is 7 days. After demolding, the lithium mica tailings solidified derivative material is prepared and the solidification of lithium mica tailings is completed.

[0087] Comparative Example 5

[0088] Steps (1) to (3) are consistent with steps (1) to (3) of Comparative Example 4.

[0089] (4) The mixed slurry, kept at 80°C, is injected into the mold and then subjected to ultrasound. The ultrasound power is 350W, the ultrasound frequency is 50kHz, and the ultrasound time is 10min to completely expel the gas. Then the mixed slurry is sealed and placed in a curing box for heating and constant temperature curing to achieve heat assistance. The heating and constant temperature curing temperature is 80°C and the curing time is 7d. After demolding, the lithium mica tailings solidified derivative material is prepared and the solidification of lithium mica tailings is completed.

[0090] Comparative Example 6

[0091] (1) Nano-sized silica (particle size 1~100nm), sodium hydroxide solid powder, potassium hydroxide solid powder, hydrated sodium silicate liquid (sodium silicate content in hydrated sodium silicate liquid is 26.7%), solid fly ash (based on the total mass of solid fly ash as 100%, it includes 43.8% SiO2, 40.9% Al2O3, 5.9% Fe2O3, 2.8% CaO, 2.7% TiO2 and other trace substances balance), lepidolite tailings (based on the total mass of lepidolite tailings as 100%, it includes 37.92% Al2O3, 26.59% Fe2O3, 18.8% CaO, 13.8% SiO2 and other trace substances balance) The mixture was mixed and mechanically stirred at a speed of 400 rpm, and heated to 80°C within 10 minutes and maintained until it was poured into a mold for heat assistance. After uniform stirring, it was ultrasonically subjected to an ultrasonic power of 350 W, an ultrasonic frequency of 50 kHz, and an ultrasonic time of 10 minutes to obtain a mixed slurry. Based on the total mass of the mixed slurry as 100%, the addition amounts of lithium mica tailings slag were 75%, solid fly ash was 2.5%, nano silica was 1.125%, sodium hydroxide solid powder was 2.25%, potassium hydroxide solid powder was 2.25%, and hydrated sodium silicate liquid was 16.875%.

[0092] (2) The mixed slurry, which is kept at 80°C, is injected into the mold and then subjected to ultrasound. The ultrasound power is 350W, the ultrasound frequency is 50kHz, and the ultrasound time is 10min to completely remove the gas. Then the mixed slurry is sealed and placed in a curing box for heating and constant temperature curing to achieve heat assistance. The heating and constant temperature curing temperature is 80°C and the curing time is 7d. After demolding, the lithium mica tailings solidified derivative material is prepared and the solidification of lithium mica tailings is completed.

[0093] Test case

[0094] The leaching concentrations of seven metals—chromium, copper, zinc, niobium, tantalum, thallium, and lead—in the solidified derivative materials of lepidolite tailings from the above embodiments and comparative examples were tested. The solidification rate was calculated using the following formula: (1 - metal leaching concentration before solidification / metal leaching concentration after solidification) × 100%.

[0095] Figure 2 The results are presented as a comparative study, based on the methods and conditions specified in HJ / T 299-2007, to test the leaching concentration and solidification rate of heavy metals in lepidolite tailings. Figure 3 The results are for comparing the solidification rate distribution of heavy metals in lepidolite tailings according to the methods and conditions in HJ / T 299-2007. Figure 4 To compare the changes and loss rates of mass and compressive strength in the freeze-thaw cycle test.

[0096] Figure 5 The results of testing the leaching concentration and solidification rate of heavy metals in lepidolite tailings according to the methods and conditions in HJ / T 299-2007 are presented as an example. Figure 6 The results of testing the solidification rate distribution of heavy metals in lepidolite tailings according to the methods and conditions in HJ / T 299-2007 are presented as an example. Figure 7 The changes and loss rates of mass and compressive strength in the freeze-thaw cycle test are shown in the example.

[0097] The compressive strength was tested according to the method described in GB / T 17671-2021. The freeze-thaw cycle test was conducted according to the method described in GB / T 50082-2009.

[0098] The test results above show that Example 1 can effectively immobilize all seven metals. The leaching concentrations of chromium, zinc, niobium, tantalum, thallium, and lead are 0.01, 1.39, 1.07, 0.60, 0.00, and 0.41 μg / L, respectively. Figure 5 All of them meet the standard requirements for leaching concentrations of different heavy metals in the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification (GB 5085.3-2007)". Furthermore, the immobilization rates of the six metals other than Cu in Examples 1-6 ranged from 98.95% to 100%, indicating stable immobilization performance. Figure 6 ).

[0099] Compared to Example 1, Comparative Example 1 did not use nano-silica as the compound activator and only used heat assistance in the sealing and curing stage; ultrasound and heat assistance were not used in other steps. Comparative Example 2 only used heat assistance in the sealing and curing stage; ultrasound and heat assistance were not used in other steps. Comparative Example 3 used ultrasound and heat assistance in the compound activator preparation stage and in the sealing and curing stage; ultrasound and heat assistance were not used in other steps. Comparative Example 4 did not use ultrasound and heat assistance in the mixed curing agent preparation stage and did not use ultrasound in the venting stage after injection molding. Comparative Example 5 did not use ultrasound and heat assistance in the mixed curing agent preparation stage. Comparative Example 6 mixed all raw materials together and subjected them to ultrasound and heat assistance (without using multi-stage ultrasound and heat assistance), and used heat assistance in the sealing and curing stage. Compared to Example 1, the heavy metal leaching concentrations of Comparative Examples 1-6 were higher than those of Example 1, and the curing rates were lower than those of Example 1.

[0100] In addition, by Figure 4 and Figure 7 The comparison shows that, compared with the comparative example, the tensile strength of the embodiment of the present invention can reach 28.6 MPa (7 days curing), and while improving the mechanical strength of the derived material, it can also improve the durability of the material, such as freeze-thaw resistance.

[0101] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for solidifying lepidolite tailings slag synergistically with fly ash under multi-segment ultrasonic thermal assistance, comprising the following steps: (1) A composite activator was prepared by selectively adding nano-silica, hydroxide and silicate, through a first stage of thermal assistance and a first stage of ultrasound. (2) Using the aforementioned compound activator and fly ash, a mixed curing agent is prepared by a second stage of thermal assistance and a second stage of ultrasonic treatment; (3) The mixed curing agent is mixed with lepidolite tailings slag and then heated in the third stage to obtain a mixed slurry; (4) The mixed slurry is molded under the fourth stage of heat-assisted conditions, then ultrasonically treated in the third stage, then sealed and cured and heat-assisted in the fifth stage, and then demolded to prepare the lithium mica tailings solidified derivative material and complete the solidification of the lithium mica tailings.

2. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 1, wherein, In step (1), the hydroxide is sodium hydroxide and potassium hydroxide; And / or, in step (1), the silicate is hydrated sodium silicate.

3. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 2, wherein, In step (1), based on the total mass of the compound activator being 100%, the dosage of nano-silica is 0-15%, the dosage of sodium hydroxide is 10-20%, the dosage of potassium hydroxide is 10-20%, and the dosage of hydrated sodium silicate is 60-80%. And / or, based on the total mass of the compound activator being 100%, the dosage of nano-silica is 5-15%, the dosage of sodium hydroxide is 10-20%, the dosage of potassium hydroxide is 10-20%, and the dosage of hydrated sodium silicate is 60-75%.

4. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 2, wherein, In step (1), the hydrated sodium silicate is a hydrated sodium silicate liquid, wherein the mass content of sodium silicate is 20~30%.

5. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 1, wherein, In step (1), the temperature of the first heat-assisted segment is 60~80℃; the ultrasonic power of the first ultrasonic segment is 250~350W, the ultrasonic frequency is 40~60kHz, and the ultrasonic time is 5~15min.

6. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 1 or 5, wherein, In step (1), a composite activator is prepared by selectively adding nano-silica, hydroxide and silicate, through a first mechanical stirring, a first stage of thermal assistance and a first stage of ultrasound; the speed of the first mechanical stirring is 250~450 rpm.

7. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 1, wherein, In step (2), based on the total mass of the mixed curing agent as 100%, the amount of compound activator added is 70-90%, and the amount of fly ash added is 10-30%.

8. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 1, wherein, In step (2), the total mass of the fly ash is 100%, which includes 40-45% SiO2, 40-45% Al2O3, 4-8% Fe2O3, 2-4% CaO, 2-4% TiO2 and other trace substances as the balance.

9. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 1, wherein, In step (2), the temperature of the second heat-assisted section is 60~80℃; the ultrasonic power of the second ultrasonic section is 250~350W, the ultrasonic frequency is 40~60kHz, and the ultrasonic time is 5~15min.

10. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 1 or 8, wherein, In step (2), the compound activator and fly ash are mixed and a mixed curing agent is prepared by second mechanical stirring, second stage of thermal assistance and second stage of ultrasound; the speed of the second mechanical stirring is 250~450 rpm.

11. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 1, wherein, In step (3), the mixing mass ratio of the lithium mica tailings slag to the mixed solidifying agent is (3:1) to (4:1).

12. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 1, wherein, In step (3), the total mass of the lithium mica tailings is 100%, which includes 30-40% Al2O3, 20-30% Fe2O3, 15-25% CaO, 10-15% SiO2 and other trace substances.

13. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 1, wherein, In step (3), the mixed curing agent is mixed with lepidolite tailings slag, and a mixed slurry is obtained by third-stage thermal assistance and third-stage mechanical stirring; the temperature of the third-stage thermal assistance is 60~80℃; the speed of the third-stage mechanical stirring is 250~450rpm.

14. The method for solidifying lithium mica tailings slag with fly ash under multi-segment ultrasonic thermal assistance according to claim 1, wherein, In step (4), the temperature of the fourth heat-assisted section is 60~80℃; the ultrasonic power of the third ultrasonic section is 250~350W, the ultrasonic frequency is 40~60kHz, and the ultrasonic time is 5~15min; the sealing and curing time is 3~10d; and the temperature of the fifth heat-assisted section is 60~80℃.

15. A lithium mica tailings solidification derivative material, which is prepared by the lithium mica tailings solidification method of fly ash under multi-segment ultrasonic thermal assistance as described in any one of claims 1-14.

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