Lithium slag dealkali treatment agents and methods for resource utilization of lithium slag in building materials

Abstract

This invention discloses a lithium slag dealkalization treatment agent and a method for the resource utilization of lithium slag in building materials, comprising the following raw materials in parts by weight: 50-80 parts sodium hydroxide, 30-50 parts water glass, 5-15 parts polycarboxylate superplasticizer, and 10-20 parts calcium carbonate. This invention has the advantage of being environmentally friendly and solves the problems of existing lithium slag resource utilization methods, such as the inconvenience of preparing high-strength, high-insulation building materials from waste lithium slag, insufficient strength of lithium slag building materials making them unsuitable for load-bearing structures or high-load scenarios, limiting their use to low-strength filler materials or non-structural components, significantly reducing their economic value, and poor insulation performance failing to meet energy-saving building standards, resulting in a lack of competitiveness in scenarios requiring thermal insulation such as walls or roofs.

Description

Technical Field

[0001] This invention relates to the field of material recycling technology, specifically to lithium slag dealkalization treatment agents and methods for the resource utilization of lithium slag building materials. Background Technology

[0002] Lithium slag dealkalization agents refer to chemical agents used to reduce the alkaline content or neutralize the alkalinity of lithium slag. This type of treatment is typically to meet the performance requirements of lithium slag in subsequent resource utilization and to avoid the negative environmental or material performance effects of excessive alkalinity. Lithium slag dealkalization agents include acidic agents and alkaline activators. Acidic agents are less expensive, but wastewater treatment costs must be considered; alkaline activators are more expensive, but allow for resource utilization.

[0003] When existing lithium slag is used for building material resource utilization, it is not convenient to prepare waste lithium slag into high-strength and high-insulation building materials. If the strength of lithium slag building materials is insufficient, they cannot be used for load-bearing structures or high-load scenarios. They can only be used for low-strength filler materials or non-structural components, which greatly reduces their economic value. If the insulation performance is poor, it is difficult to meet the energy-saving building standards and lacks competitiveness in scenarios such as walls or roofs that require heat and cold insulation. Summary of the Invention

[0004] The purpose of this invention is to provide a lithium slag dealkalization treatment agent and a method for the resource utilization of lithium slag building materials. It has the advantages of being environmentally friendly and solves the problems of existing lithium slag resource utilization, such as the inconvenience of preparing waste lithium slag into high-strength and high-insulation building materials, the inability of lithium slag building materials to be used in load-bearing structures or high-load scenarios if the strength of lithium slag building materials is insufficient, and the inability to be used in load-bearing structures or high-load scenarios, and the inability to be used in low-strength filler materials or non-structural components, which greatly reduces their economic value, and the lack of competitiveness in scenarios such as walls or roofs that require heat insulation and cold insulation if the insulation performance is poor.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a lithium slag dealkalization treatment agent, comprising the following raw materials in parts by weight:

[0006] Sodium hydroxide 50-80 parts, water glass 30-50 parts, polycarboxylate superplasticizer 5-15 parts, calcium carbonate 10-20 parts.

[0007] 3. A method for the resource utilization of lithium slag in building materials using lithium slag dealkali treatment agents, comprising the following steps:

[0008] S1. Lithium slag treatment: The lithium slag is dried to a moisture content of 5-10%, and then the dried lithium slag is crushed to a particle size of 100-150μm.

[0009] S2. Raw material treatment for lithium slag dealkalization: Weigh out sodium hydroxide, water glass, polycarboxylate superplasticizer and calcium carbonate in proportion.

[0010] S3. Preparation of dealkali treatment agent for lithium slag: Dissolve solid sodium hydroxide in distilled water to prepare a 5-8 mol / L sodium hydroxide solution. Then prepare water glass as a solvent and mix it with the sodium hydroxide solution. Finally, add water-reducing agent and calcium carbonate and stir to mix. After mixing evenly, let it stand for 2-4 hours.

[0011] S4. Lithium slag dealkali treatment: Mix the dealkali treatment agent after it has been settling with lithium slag at a mass ratio of 1:5-1:20, and add water to stir into a slurry to obtain alkali-activated cementitious material.

[0012] S5. Resource utilization of building materials: Alkali-activated cementitious materials are mixed with PVA fibers and expanded perlite in a mixing equipment. After mixing, the mixture is sent to a grinding equipment for grinding and crushing. The ground slurry is then sent to a granulation equipment to prepare building material granules.

[0013] S6. Curing and Screening: The building material particles are subjected to pressurized hydrothermal steam curing at a temperature of 60–200℃ and a pressure of 0.8–1.2MPa for 2–8 hours to obtain high-strength and high-insulation building materials for building reinforcement and insulation. The building materials are screened using a vibrating screen to remove uncured particles and particles with unqualified particle size, and finally the building material particles with a particle size of 0.5-1mm are screened out.

[0014] In a preferred embodiment of the lithium slag dealkali treatment agent of the present invention, the lithium slag is pre-crushed before drying in step S1. A mechanical crusher is used for pre-crushing to produce lithium slag particles with a diameter of 1-2 cm. During drying, a multi-stage drying system is used, including a co-current dryer and a counter-current dryer. The co-current dryer uses a temperature of 150–250°C for rapid high-temperature dehydration, while the counter-current dryer uses a low temperature of 100–120°C for deep drying, ensuring a final moisture content of 5-10%. During the drying process, the waste heat from the drying exhaust gas is used to preheat the feed material through a waste heat recovery device, reducing energy consumption. After drying, an air jet mill is used for crushing. The air jet mill utilizes high-speed airflow to impact the lithium slag particles, achieving ultrafine crushing. A centrifugal classifier or cyclone separator is installed at the discharge end of the mill to screen the crushed lithium slag particles and control the particle size range.

[0015] In a preferred method for the resource utilization of lithium slag building materials, which is used as the lithium slag dealkali treatment agent of the present invention, when determining the ratio of sodium hydroxide and calcium carbonate in S2, the alkaline components in the lithium slag are detected in real time by X-ray fluorescence or ion chromatography, and the proportions of sodium hydroxide and calcium carbonate are dynamically adjusted according to the detection data. The proportions of water glass and polycarboxylate superplasticizer are also adjusted according to the proportions of sodium hydroxide and calcium carbonate.

[0016] In the preferred embodiment of the lithium slag dealkali treatment agent of the present invention, the lithium slag building material resource utilization method is as follows: during the mixing process in S3, a planetary mixer is used for mixing. The speed of the planetary mixer is 1000–1500 rpm. The mixing structure inside the planetary mixer achieves uniform dispersion of the agent through eddy shear force. During the mixing process, ultrasonic waves are also used to break up particles in the solvent, thereby shortening the dissolution and mixing time.

[0017] In a preferred embodiment of the lithium slag dealkali treatment agent of the present invention, the lithium slag building material resource utilization method involves mixing in step S4. First, the mixture is stirred at 60–80°C for 10–15 minutes to promote the initial reaction between the alkali activator and the lithium slag. Then, the temperature is increased to 100–120°C to accelerate silicate formation. During heating, the slurry temperature is controlled by an electric heating jacket or a steam heating jacket to ensure uniform heating of the reaction system. A temperature sensor is used to detect the reaction temperature in real time, and the detected temperature data is transmitted to a controller. The controller controls the electric heating jacket and the steam heating jacket based on the detected data and the pre-selected segmented temperature values. During the mixing process, dynamic pH adjustment is performed. A pH sensor detects the pH value of the slurry. When the pH value is higher than the set value, borax or phosphate is added as a buffer to maintain the pH value of the slurry at 10–11.

[0018] In the preferred method for the resource utilization of lithium slag building materials using the lithium slag dealkali treatment agent of the present invention, the granulation equipment in S5 is a high-pressure spray drying tower. Before granulation, the slurry is filtered and concentrated to remove large particulate impurities and adjust the slurry concentration to meet the requirements of spray drying. The slurry is sent to a diaphragm pump through a pipeline conveying system. The diaphragm pump delivers the slurry to the nozzle. Under high pressure, the slurry is sprayed out of the nozzle at high speed, forming a high-speed liquid film and splitting into droplets. At the same time, air is heated to 150-200°C by an electric heater or a steam heater and enters from the top of the drying tower. The hot air and the atomized droplets flow down in parallel in the drying tower. The water in the droplets evaporates rapidly, and the solid components solidify to form spherical particles. The dried particles settle to the bottom of the drying tower due to gravity and are discharged from the outlet through the funnel cavity. The fine powder particles that have not settled completely enter the cyclone separator along with the hot air and are separated by centrifugal force. The remaining exhaust gas containing micro powder is further filtered by a bag filter to ensure harmless emission.

[0019] In the preferred method for the resource utilization of lithium slag building materials using the lithium slag dealkali treatment agent of the present invention, during pressurized hydrothermal steam curing in S6, the temperature is increased in three stages: the initial stage is 60-100℃, the heating stage is 120-160℃, and the steam curing stage is 180-200℃, with each stage lasting 0.5-2 hours to reduce thermal stress. Furthermore, the pressure is dynamically adjusted according to the degree of particle hardening during the curing process: the initial stage pressure is 0.8MPa, the intermediate stage pressure is 1.0MPa, and the later stage pressure is 1.2MPa to improve density.

[0020] In the preferred embodiment of the lithium slag dealkali treatment agent of the present invention, when using a vibrating screen to screen building materials in S6, a three-stage vibrating screen is used for step-by-step screening. The three-stage vibrating screen is equipped with screens with apertures of 2mm, 1mm and 0.5mm respectively. The particles are screened through screens with different apertures. During the screening process, a low-pressure airflow with a pressure of 0.1-0.2MPa is blown into the top of the screen. The low-pressure airflow disperses the fine powder and improves the screening efficiency.

[0021] The preferred method for the resource utilization of lithium slag building materials, which is used as the lithium slag dealkali treatment agent of the present invention, involves the following steps: The screened 0.5-1mm building material particles are subjected to compressive strength testing; a compressive strength ≥30MPa is acceptable. The thermal conductivity of the building material particles is measured using a thermal conductivity tester; a thermal conductivity ≤0.1W / m·K is acceptable. The mineral composition of the building material particles is analyzed by X-ray diffraction to ensure the absence of harmful impurities. The corrosion resistance of the building material particles is tested using an acid-base leaching test. The particle size distribution of the building material particles is detected using a laser particle size analyzer to ensure that 95% of the particles are within the range of 0.5-1mm.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. This invention achieves harmless treatment and high-value utilization of lithium slag throughout the entire chain through lithium slag dealkalization treatment agents and their resource utilization methods. It significantly reduces the environmental risks caused by traditional lithium slag stockpiling or inefficient treatment. As a high-risk solid waste in lithium battery production, lithium slag is prone to soil and water pollution and waste of land resources through traditional landfilling or low-value utilization methods. This solution effectively removes harmful alkaline components by chemically reacting the dealkalization treatment agents with lithium slag and converts them into alkali-activated cementitious materials, which are then used to prepare high-strength, high-insulation building materials, achieving a resource utilization rate of over 95% for lithium slag.

[0024] 2. This invention significantly improves the performance and production efficiency of building materials through multi-dimensional process optimization and precise control technology, providing a replicable technical path for the high-value utilization of lithium slag. It employs dynamic ratio adjustment and real-time pH control, combined with X-ray fluorescence detection of lithium slag components, ensuring a sufficient and stable reaction between the dealkali agent and the lithium slag, avoiding product defects caused by excessive or insufficient alkali. The high-pressure spray drying tower, through eddy current shear force stirring and a multi-stage sieving system, prepares spherical particles with uniform particle size. Combined with three-stage hydrothermal curing, the building material particles exhibit high compressive strength and thermal conductivity, meeting the requirements for building insulation and structural reinforcement. By replacing traditional building material raw materials at low cost, it reduces production costs and provides a green circular solution for the new energy industry chain. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the preparation process of the present invention. Detailed Implementation

[0026] Example 1

[0027] The lithium slag dealkali treatment agent comprises the following raw materials in parts by weight:

[0028] Sodium hydroxide 50-80 parts, water glass 30-50 parts, polycarboxylate superplasticizer 5-15 parts, calcium carbonate 10-20 parts.

[0029] Sodium hydroxide, as a strong alkaline component, can effectively neutralize the free alkali in lithium slag, reducing its corrosiveness and environmental hazards. Water glass provides a silicon source, reacting with the alkaline components to form a stable silicate network structure, fixing harmful substances. Calcium carbonate further adjusts the pH value of the system through an acid-base neutralization reaction, avoiding the brittleness of building materials caused by excessive alkalinity. Polycarboxylate superplasticizer optimizes the fluidity of the slurry, ensuring full contact between the agent and the lithium slag, and improving reaction efficiency. This agent system transforms lithium slag into a cementitious material through an alkaline-activated reaction, replacing traditional cement raw materials, reducing carbon emissions. The final building material particles possess both high strength and low thermal conductivity, meeting the requirements for building insulation and structural reinforcement, while simultaneously realizing the resource utilization of lithium slag.

[0030] Example 2

[0031] Please see Figure 1 A method for the resource utilization of lithium slag in building materials using lithium slag dealkali treatment agents includes the following steps:

[0032] S1. Lithium slag treatment: The lithium slag is dried to a moisture content of 5-10%, and then the dried lithium slag is crushed to a particle size of 100-150μm.

[0033] S2. Raw material treatment for lithium slag dealkalization: Weigh out sodium hydroxide, water glass, polycarboxylate superplasticizer and calcium carbonate in proportion.

[0034] S3. Preparation of dealkali treatment agent for lithium slag: Dissolve solid sodium hydroxide in distilled water to prepare a 5-8 mol / L sodium hydroxide solution. Then prepare water glass as a solvent and mix it with the sodium hydroxide solution. Finally, add water-reducing agent and calcium carbonate and stir to mix. After mixing evenly, let it stand for 2-4 hours.

[0035] S4. Lithium slag dealkali treatment: Mix the dealkali treatment agent after it has been settling with lithium slag at a mass ratio of 1:5-1:20, and add water to stir into a slurry to obtain alkali-activated cementitious material.

[0036] S5. Resource utilization of building materials: Alkali-activated cementitious materials are mixed with PVA fibers and expanded perlite in a mixing equipment. After mixing, the mixture is sent to a grinding equipment for grinding and crushing. The ground slurry is then sent to a granulation equipment to prepare building material granules.

[0037] S6. Curing and Screening: The building material particles are subjected to pressurized hydrothermal steam curing at a temperature of 60–200℃ and a pressure of 0.8–1.2MPa for 2–8 hours to obtain high-strength and high-insulation building materials for building reinforcement and insulation. The building materials are screened using a vibrating screen to remove uncured particles and particles with unqualified particle size, and finally the building material particles with a particle size of 0.5-1mm are screened out.

[0038] Furthermore, before drying the lithium slag, S1 pre-crushes the lithium slag using a mechanical crusher to produce lithium slag particles with a diameter of 1-2 cm. During drying, a multi-stage drying system is used, including a co-current dryer and a counter-current dryer. The co-current dryer uses a temperature of 150-250℃ for high-temperature rapid dehydration, while the counter-current dryer uses a low temperature of 100-120℃ for deep drying, ensuring a final moisture content of 5-10%. During the drying process, the waste heat from the drying exhaust gas is used to preheat the feed through a waste heat recovery device, reducing energy consumption. After drying, an air jet mill is used for crushing. The air jet mill uses high-speed airflow to impact the lithium slag particles to achieve ultrafine crushing. A centrifugal classifier or cyclone separator is installed at the discharge end of the mill to screen the crushed lithium slag particles and control the particle size range.

[0039] Furthermore, when determining the ratio of sodium hydroxide and calcium carbonate in S2, the alkaline components in the lithium slag are detected in real time by X-ray fluorescence or ion chromatography, and the proportions of sodium hydroxide and calcium carbonate are dynamically adjusted based on the detection data. The proportions of water glass and polycarboxylate superplasticizer are also adjusted according to the proportions of sodium hydroxide and calcium carbonate.

[0040] Furthermore, in S3, a planetary mixer is used for mixing. The planetary mixer rotates at 1000–1500 rpm. The mixing structure inside the planetary mixer achieves uniform dispersion of the agent through eddy shear force. During the mixing process, ultrasonic waves are also used to break up particles in the solvent, shortening the dissolution and mixing time.

[0041] Furthermore, during mixing in S4, the mixture is first stirred at 60–80°C for 10–15 minutes to promote the initial reaction between the alkali activator and the lithium slag. Then, the temperature is increased to 100–120°C to accelerate silicate formation. During heating, the slurry temperature is controlled by an electric heating jacket or a steam heating jacket to ensure uniform heating of the reaction system. A temperature sensor is used to detect the reaction temperature in real time, and the detected temperature data is transmitted to the controller. The controller controls the electric heating jacket and the steam heating jacket based on the detected data and the pre-selected segmented temperature values. During the mixing process, the pH is dynamically adjusted. The pH value of the slurry is detected by a pH sensor. When the pH value is higher than the set value, borax or phosphate is added as a buffer to maintain the pH value of the slurry at 10–11.

[0042] Furthermore, the granulation equipment in S5 is a high-pressure spray drying tower. Before granulation, the slurry is filtered and concentrated to remove large particulate impurities and adjust the slurry concentration to meet the requirements of spray drying. The slurry is sent to a diaphragm pump through a pipeline system. The diaphragm pump delivers the slurry to the nozzle. Under high pressure, the slurry is sprayed out of the nozzle at high speed, forming a high-speed liquid film that breaks into droplets. At the same time, air is heated to 150–200°C by an electric heater or a steam heater and enters from the top of the drying tower. The hot air and the atomized droplets flow down in parallel in the drying tower. The water in the droplets evaporates rapidly, and the solid components solidify to form spherical particles. The dried particles settle to the bottom of the drying tower due to gravity and are discharged from the outlet through the funnel-shaped cavity. The fine powder particles that have not settled completely enter the cyclone separator along with the hot air and are separated by centrifugal force. The remaining exhaust gas containing microparticles is further filtered by a bag filter to ensure harmless emissions.

[0043] Furthermore, during pressurized hydrothermal steam curing in S6, the temperature is increased in three stages: the initial stage is 60-100℃, the heating stage is 120-160℃, and the steam curing stage is 180-200℃, with each stage lasting 0.5-2 hours to reduce thermal stress. During the curing process, the pressure is dynamically adjusted according to the degree of particle hardening: the initial stage pressure is 0.8MPa, the middle stage pressure is 1.0MPa, and the later stage pressure is 1.2MPa to improve density.

[0044] Furthermore, when using a vibrating screen to screen building materials in S6, a three-stage vibrating screen is used for step-by-step screening. The three-stage vibrating screen is equipped with screens with apertures of 2mm, 1mm and 0.5mm respectively. Particles are screened through screens with different apertures. During the screening process, a low-pressure airflow with a pressure of 0.1-0.2MPa is blown into the top of the screen. The low-pressure airflow disperses the fine powder and improves the screening efficiency.

[0045] Furthermore, the 0.5-1mm building material particles were subjected to compressive strength testing. A compressive strength ≥30MPa was deemed acceptable. The thermal conductivity of the building material particles was measured using a thermal conductivity meter. A thermal conductivity ≤0.1W / m·K was deemed acceptable. The mineral composition of the building material particles was analyzed by X-ray diffraction to ensure the absence of harmful impurities. The corrosion resistance of the building material particles was tested using an acid-base leaching test. The particle size distribution of the building material particles was detected using a laser particle size analyzer to ensure that 95% of the particles were within the 0.5-1mm range.

[0046] By using dealkali treatment agents for lithium slag and their resource utilization methods, the harmless treatment and high-value utilization of lithium slag throughout the entire chain have been achieved. This significantly reduces the environmental risks caused by traditional lithium slag stockpiling or inefficient treatment. As a high-risk solid waste in lithium battery production, traditional landfilling or low-value utilization methods can easily cause soil and water pollution and waste of land resources. This solution effectively removes harmful alkaline components by chemically reacting dealkali treatment agents with lithium slag and converts them into alkali-activated cementitious materials, which are then used to prepare high-strength, high-insulation building materials, achieving a resource utilization rate of over 95% for lithium slag.

[0047] Through multi-dimensional process optimization and precise control technology, the performance and production efficiency of building materials have been significantly improved, providing a replicable technical path for the high-value utilization of lithium slag. Dynamic ratio adjustment and real-time pH control are adopted, combined with X-ray fluorescence detection of lithium slag components, to ensure that the reaction between the dealkali agent and lithium slag is sufficient and stable, avoiding product defects caused by excessive or insufficient alkali. The high-pressure spray drying tower produces spherical particles with uniform particle size through eddy shear force stirring and multi-stage screening system. Combined with three-stage hydrothermal curing, the building material particles have high compressive strength and thermal conductivity, meeting the requirements of building insulation and structural reinforcement. By replacing traditional building material raw materials at low cost, production costs are reduced, while providing a green circular solution for the new energy industry chain.

[0048] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for the resource utilization of lithium slag in building materials using lithium slag dealkali treatment agents, characterized in that, The ingredients include the following parts by weight: Sodium hydroxide 50-80 parts, water glass 30-50 parts, polycarboxylate superplasticizer 5-15 parts, calcium carbonate 10-20 parts; It also includes the following steps: S1. Lithium slag treatment: The lithium slag is dried to a moisture content of 5-10%, and then the dried lithium slag is crushed to a particle size of 100-150μm. S2. Raw material treatment for lithium slag dealkalization: Weigh out sodium hydroxide, water glass, polycarboxylate superplasticizer and calcium carbonate in proportion. S3. Preparation of dealkali treatment agent for lithium slag: Dissolve solid sodium hydroxide in distilled water to prepare a 5-8 mol / L sodium hydroxide solution. Then prepare water glass as a solvent and mix it with the sodium hydroxide solution. Finally, add water-reducing agent and calcium carbonate and stir to mix. After mixing evenly, let it stand for 2-4 hours. S4. Lithium slag dealkali treatment: Mix the dealkali treatment agent after it has been settling with lithium slag at a mass ratio of 1:5-1:20, and add water to stir into a slurry to obtain alkali-activated cementitious material. S5. Resource utilization of building materials: Alkali-activated cementitious materials are mixed with PVA fibers and expanded perlite in a mixing equipment. After mixing, the mixture is sent to a grinding equipment for grinding and crushing. The ground slurry is then sent to a granulation equipment to prepare building material granules. S6. Curing and Screening: The building material particles are subjected to pressurized hydrothermal steam curing at a temperature of 60–200℃ and a pressure of 0.8–1.2MPa for 2–8 hours to obtain high-strength and high-insulation building materials for building reinforcement and insulation. The building materials are screened using a vibrating screen to remove uncured particles and particles with unqualified particle size, and finally the building material particles with a particle size of 0.5-1mm are screened out.

2. The method for resource utilization of lithium slag in building materials using the lithium slag dealkali treatment agent according to claim 1, characterized in that: Before drying the lithium slag, the S1 process involves pre-crushing it using a mechanical crusher to produce lithium slag particles with a diameter of 1-2 cm. During drying, a multi-stage drying system is used, including a co-current dryer and a counter-current dryer. The co-current dryer uses a temperature of 150–250℃ for rapid high-temperature dehydration, while the counter-current dryer uses a low temperature of 100–120℃ for deep drying, ensuring a final moisture content of 5-10%. During the drying process, a waste heat recovery device uses the waste heat from the drying exhaust gas to preheat the feed, reducing energy consumption. After drying, an air jet mill is used for further crushing. This mill utilizes high-speed airflow to impact the lithium slag particles, achieving ultrafine crushing. A centrifugal classifier or cyclone separator is installed at the mill's discharge end to screen the crushed lithium slag particles and control their size range.

3. The method for resource utilization of lithium slag in building materials using the lithium slag dealkali treatment agent according to claim 2, characterized in that: When determining the ratio of sodium hydroxide and calcium carbonate in S2, the alkaline components in the lithium slag are detected in real time by X-ray fluorescence or ion chromatography. Based on the detection data, the proportions of sodium hydroxide and calcium carbonate are dynamically adjusted, and the proportions of water glass and polycarboxylate superplasticizer are adjusted according to the proportions of sodium hydroxide and calcium carbonate.

4. The method for resource utilization of lithium slag in building materials using the lithium slag dealkali treatment agent according to claim 3, characterized in that: In S3, a planetary mixer is used for mixing. The planetary mixer rotates at 1000–1500 rpm. The mixing structure inside the planetary mixer achieves uniform dispersion of the agent through eddy shear force. Ultrasonic waves are also used to break up particles in the solvent during the mixing process, shortening the dissolution and mixing time.

5. The method for resource utilization of lithium slag in building materials using the lithium slag dealkali treatment agent according to claim 4, characterized in that: During mixing in S4, the mixture is first stirred at 60–80℃ for 10–15 minutes to promote the initial reaction between the alkali activator and the lithium slag. Then, the temperature is increased to 100–120℃ to accelerate silicate formation. During heating, the slurry temperature is controlled by an electric heating jacket or a steam heating jacket to ensure uniform heating of the reaction system. A temperature sensor is used to detect the reaction temperature in real time, and the detected temperature data is transmitted to the controller. The controller controls the electric heating jacket and the steam heating jacket based on the detected data and the pre-selected segmented temperature values. During the mixing process, the pH is dynamically adjusted. The pH value of the slurry is detected by a pH sensor. When the pH value is higher than the set value, borax or phosphate is added as a buffer to maintain the pH value of the slurry at 10–11.

6. The method for resource utilization of lithium slag in building materials using the lithium slag dealkali treatment agent according to claim 5, characterized in that: The granulation equipment in S5 is a high-pressure spray drying tower. Before granulation, the slurry is filtered and concentrated to remove large particles and adjust the slurry concentration to meet the requirements of spray drying. The slurry is sent to a diaphragm pump through a pipeline system. The diaphragm pump delivers the slurry to the nozzle. Under high pressure, the slurry is sprayed out of the nozzle at high speed, forming a high-speed liquid film that breaks into droplets. At the same time, air is heated to 150–200°C by an electric heater or a steam heater and enters from the top of the drying tower. The hot air and the atomized droplets flow down in parallel in the drying tower. The water in the droplets evaporates rapidly, and the solid components solidify to form spherical particles. The dried particles settle to the bottom of the drying tower due to gravity and are discharged from the outlet through the funnel cavity. The fine powder particles that have not settled completely enter the cyclone separator along with the hot air and are separated by centrifugal force. The remaining exhaust gas containing fine powder is further filtered by a bag filter to ensure harmless emission.

7. The method for resource utilization of lithium slag in building materials using the lithium slag dealkali treatment agent according to claim 6, characterized in that: During pressurized hydrothermal steam curing in S6, the temperature is increased in three stages: the initial stage is 60-100℃, the heating stage is 120-160℃, and the steam curing stage is 180-200℃. Each stage lasts for 0.5-2 hours to reduce thermal stress. During the curing process, the pressure is dynamically adjusted according to the degree of particle hardening: the initial stage pressure is 0.8 MPa, the middle stage pressure is 1.0 MPa, and the later stage pressure is 1.2 MPa to improve density.

8. The method for resource utilization of lithium slag in building materials using the lithium slag dealkali treatment agent according to claim 7, characterized in that: When using a vibrating screen to screen building materials in S6, a three-stage vibrating screen is used for step-by-step screening. The three-stage vibrating screen is equipped with screens with apertures of 2 mm, 1 mm and 0.5 mm respectively. Particles are screened through screens with different apertures. During the screening process, a low-pressure airflow with a pressure of 0.1-0.2 MPa is blown into the top of the screen. The low-pressure airflow disperses the fine powder and improves the screening efficiency.

9. The method for resource utilization of lithium slag in building materials using the lithium slag dealkali treatment agent according to claim 8, characterized in that: The 0.5-1mm building material particles were subjected to compressive strength testing. A compressive strength ≥30 MPa was acceptable. The thermal conductivity of the building material particles was measured using a thermal conductivity tester. A thermal conductivity ≤0.1 W / m·K was acceptable. The mineral composition of the building material particles was analyzed by X-ray diffraction to ensure the absence of harmful impurities. The corrosion resistance of the building material particles was tested by acid-base leaching test. The particle size distribution of the building material particles was detected by a laser particle size analyzer to ensure that 95% of the particles were within the 0.5-1mm range.

Images