A method for extracting lanthanum from claystone using activated carbon based on liquor lees.

Abstract

This invention relates to a method for extracting lanthanum from clay rock ion-adsorption rare earth minerals using activated carbon based on liquor lees in the field of rare earth extraction technology. The method uses liquor lees, a byproduct of liquor brewing, as raw material. High-specific-surface-area activated carbon based on liquor lees is prepared through drying, pulverizing, low-temperature carbonization, and high-temperature activation with zinc chloride. This activated carbon is then mixed with clay rock ion-adsorption rare earth minerals. An ammonium sulfate weakly acidic leaching system is used to achieve an integrated process of in-situ leaching and simultaneous selective adsorption of lanthanum ions. High-purity lanthanum oxide is then prepared through desorption with dilute hydrochloric acid, impurity removal, ammonia precipitation, and low-temperature calcination. This method solves the problem of high pollution in existing ion-adsorption rare earth extraction processes.

Description

Technical Field

[0001] This invention relates to the field of rare earth extraction technology, specifically to a method for extracting lanthanum from clay rock ion-adsorption type rare earths using activated carbon based on liquor lees. Background Technology

[0002] Ion-adsorption rare earth minerals are a unique strategic mineral resource in my country, widely distributed in southern provinces such as Jiangxi, Fujian, and Guangdong. Rare earth elements are adsorbed onto the surface of clay minerals in an ionic state. Lanthanum (La), as a core element of light rare earths, has wide applications in catalysis, energy storage, and ceramics. Currently, the mainstream industrial process for extracting ion-adsorption rare earths is the ammonium sulfate in-situ leaching-oxalic acid precipitation method. This process has problems such as large ammonia nitrogen wastewater discharge, high oxalic acid cost, and low rare earth recovery rate (lanthanum recovery rate is about 75%~82%). In addition, the leachate contains high levels of impurity ions such as aluminum and iron, making subsequent purification processes complex.

[0003] Distillery lees are a major byproduct of the baijiu (Chinese liquor) brewing industry, with my country producing 10-15 million tons of dried lees annually. Traditional disposal methods include landfilling, incineration, or animal feed, resulting in resource waste and environmental pollution. Distillery lees are rich in cellulose, lignin, and crude protein, making them an excellent precursor for biomass activated carbon. Currently, distillery lees-based activated carbon is primarily used for wastewater decolorization and organic pollutant adsorption; however, there are no reports of its application in ion-adsorption type rare earth lanthanum extraction.

[0004] In existing rare earth extraction technologies, activated carbon is mostly used as an auxiliary adsorbent for enrichment at the back end of the leachate, failing to achieve integrated "leaching-adsorption." Furthermore, commercially available activated carbon is primarily made from coal and wood, resulting in high costs that do not align with the concept of green and low-carbon development. Therefore, developing a method for efficiently and environmentally friendly extraction of lanthanum from clay rock ion-adsorption rare earth elements using activated carbon derived from liquor lees as the core material has significant engineering application value and environmental implications. Summary of the Invention

[0005] The present invention aims to provide a method for extracting lanthanum from clay rock ion-adsorption rare earth elements using activated carbon based on liquor lees, in order to solve the problem of high pollution in existing ion-adsorption rare earth extraction processes.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for extracting lanthanum from clay rock ion-adsorption rare earth elements using activated carbon based on liquor lees, comprising the following steps: S1, Preparation of activated carbon based on baijiu lees: After removing impurities from baijiu lees, dry, crush, and sieve to obtain lees powder; carbonize the lees powder under nitrogen protection to obtain carbonized lees powder; mix the carbonized lees powder with zinc chloride activation solution, ultrasonically impregnate, dry, activate, wash with water, and dry to obtain activated carbon based on baijiu lees. S2, Pretreatment of clay rock rare earth ore: Take clay rock ion-adsorption type rare earth ore, crush it, sieve it and air dry it for later use; the mass content of lanthanum ion phase in clay rock ion-adsorption type rare earth ore is ≥0.08%; S3, Composite Leaching and Adsorption: The pretreated rare earth ore in S2 is mixed with distillers' grains-based activated carbon at a mass ratio of 5~8:1 and loaded into a column leaching device; a 0.2~0.3mol / L ammonium sulfate leaching solution is prepared, the pH is adjusted to 5.0~5.5, and the solution is introduced into the column leaching device from top to bottom at a liquid-to-solid ratio of 3~4:1 and a flow rate of 2~3mL / min. The leaching and adsorption integrated reaction is carried out at room temperature, and then the effluent is collected until the lanthanum concentration in the effluent is ≤0.01g / L and the flow is stopped. S4, activated carbon desorption: Take out the distillers' grains-based activated carbon after lanthanum adsorption, load it into the desorption column, use 0.5~0.8mol / L hydrochloric acid solution as desorbent, and pass it into the desorption column at a flow rate of 1.5~2mL / min. Desorb at room temperature, collect the desorption solution, and stop when the lanthanum concentration in the desorption solution is ≤0.05g / L to obtain lanthanum-rich desorption solution; S5, Lanthanum enrichment and purification: Add 1~2g / L activated carbon to the lanthanum-rich desorption solution for decolorization and impurity removal. After filtration, slowly add 2~3mol / L ammonia water to the filtrate to adjust the pH to 7.0~7.5, generating lanthanum hydroxide precipitate. Filter and wash the precipitate until chloride ions are removed, dry at 80~90℃, and calcine at 450~500℃ for 1~1.5h to obtain lanthanum oxide product.

[0007] Preferably, as an improvement, in step S1, the baijiu lees are dried at 80~100℃ to a moisture content of ≤10%, and an 80~100 mesh sieve is used for sieving; a stepped temperature control process is used, in a nitrogen atmosphere, the temperature is first raised to 350~400℃ at a heating rate of 3~5℃ / min for pre-carbonization, and held at this temperature for 0.5h, and then raised to 550~580℃ at a heating rate of 5~8℃ / min for main carbonization, and then held at this temperature for 1.5~2h.

[0008] Preferably, as an improvement, the concentration of the zinc chloride activation solution in step S1 is 4~6 mol / L, the mass-to-volume ratio of carbonized distiller's grains powder to zinc chloride activation solution is 1:3~5; the ultrasonic impregnation power is 300~400W, the impregnation time is 2~3h, and the drying temperature after impregnation is 110~120℃.

[0009] Preferably, as an improvement, during activation in step S1, under a nitrogen atmosphere, the temperature is first increased to 600℃ at a rate of 5℃ / min for pre-activation and held for 0.3h, then increased to the activation temperature of 820~850℃ at a rate of 6~10℃ / min and held for 1~1.5h; after activation, the solution is washed with water until the pH of the filtrate is 6~7, thus obtaining a product with a specific surface area ≥1100m². 2 / g, microporosity ≥78%, surface energy 42.5~48.3mJ / m2 Activated carbon based on liquor lees.

[0010] Preferably, as an improvement, in step S2, the clay rock ion adsorption type rare earth ore is crushed, passed through a 40-60 mesh sieve, and air-dried until the moisture content is ≤15%.

[0011] The advantages of this solution are: 1. Compared with existing technologies, this solution uses waste liquor lees as raw materials to achieve high-value resource utilization of solid waste and eliminate solid waste pollution; it eliminates the need for oxalic acid precipitation agents, significantly reducing the cost of chemical consumables; the discharge of ammonia nitrogen wastewater is reduced by more than 30% compared with traditional processes, and the environmental pressure is significantly reduced.

[0012] 2. This solution involves the customized preparation of distillers' grains-based activated carbon through low-temperature carbonization and high-temperature activation with zinc chloride. This results in a well-developed microporous structure and abundant hydroxyl and carboxyl active functional groups, enabling it to selectively adsorb lanthanum ions. It can effectively shield associated impurity ions such as iron, aluminum, and calcium, thus solving the industry pain points of poor selectivity and co-adsorption of impurities in traditional adsorption materials and significantly improving product purity.

[0013] 3. This solution abandons the traditional single constant-temperature carbonization and activation mode, and innovatively adopts a segmented temperature control process of stepped pre-carbonization, gradient pre-activation and high-temperature final activation. This precisely controls the pyrolysis reaction process. Low-temperature pre-carbonization can smoothly remove volatiles from the distiller's grains, avoiding pore collapse caused by rapid pyrolysis and constructing a complete porous framework. Gradient pre-activation can slowly expand the initial pores, providing reaction channels for high-temperature activation. The precise high-temperature activation at 820-850℃ can maximize the ZnCl2 etching effect, significantly increase the specific surface area and micropore ratio of activated carbon, and controllably enrich highly active oxygen-containing functional groups, increasing the surface energy of the material to 42.5-48.3 mJ / m. 2 The surface energy is far higher than that of activated carbon prepared by traditional processes. The high specific surface area provides ample adsorption sites, and the high surface energy greatly enhances the atomic reactivity of the activated carbon surface, giving the material a unique chemical adsorption driving force for lanthanum ions. It can effectively shield associated impurity ions such as iron, aluminum, and calcium, and significantly improve the lanthanum enrichment efficiency and product purity. Detailed Implementation

[0014] The following detailed description illustrates the specific implementation method: Example 1 A method for extracting lanthanum from claystone ion-adsorption rare earth elements using activated carbon based on baijiu (Chinese liquor) lees includes the following steps: S1, Preparation of activated carbon based on baijiu lees: Fresh baijiu lees are selected, impurities such as rice husks and stones are removed, and the lees are dried in a 90℃ oven until the moisture content is ≤10%. After pulverization, the lees are passed through a 100-mesh sieve to obtain fine lees powder. The lees powder is placed in a tube furnace under nitrogen protection and a stepped temperature control process is used. First, the temperature is increased to 350℃ at a rate of 3℃ / min for pre-carbonization and held for 0.5h. Then, the temperature is increased to 550℃ at a rate of 5℃ / min and held for carbonization for 2h. The carbonized lees powder is then naturally cooled to room temperature to obtain carbonized lees powder. The carbonized lees powder is then mixed with 5mol / L... The ZnCl2 activation solution was mixed at a material-to-liquid ratio of 1:4, ultrasonically impregnated at 350W for 2.5 hours, and then completely dried at 115℃. The mixture was then placed in a tube furnace and pre-activated at 600℃ under nitrogen protection, first by increasing the temperature at 5℃ / min to 600℃ and holding for 0.3 hours, then by increasing the temperature at 8℃ / min to 820℃ for high-temperature activation for 1.2 hours. After cooling, the mixture was repeatedly washed with deionized water until the pH of the filtrate reached 6.5, and then dried at 115℃ to obtain a product with a specific surface area ≥1100 m². 2 / g, microporosity ≥78%, surface energy 42.5~48.3mJ / m 2 Activated carbon based on liquor lees.

[0015] S2, Pretreatment of clay rock rare earth ore: Take clay rock ion-adsorption type rare earth ore, crush it, pass it through a 50-mesh sieve, and air-dry it until the moisture content is ≤12% for later use; the mass content of lanthanum ion phase in clay rock ion-adsorption type rare earth ore is ≥0.08%; S3, Composite Leaching and Adsorption: The pretreated rare earth ore from S2 is mixed with distillers' grains-based activated carbon at a mass ratio of 6:1 and loaded into a column leaching device; a 0.25 mol / L ammonium sulfate leaching solution is prepared, the pH is adjusted to 5.2, and the solution is introduced into the column leaching device from top to bottom at a liquid-to-solid ratio of 3.5:1 and a flow rate of 2.5 mL / min. The leaching and adsorption are carried out at room temperature, and then the effluent is collected until the lanthanum concentration in the effluent is ≤0.01 g / L and then the flow is stopped. S4, activated carbon desorption: Take out the distillers' grains-based activated carbon after lanthanum adsorption, load it into the desorption column, use 0.6 mol / L hydrochloric acid solution as the desorbent, and pass it into the desorption column at a flow rate of 2 mL / min. Desorb at room temperature, collect the desorption liquid, and stop when the lanthanum concentration in the desorption liquid is ≤0.05 g / L to obtain lanthanum-rich desorption liquid. S5, Lanthanum enrichment and purification: 1.5 g / L activated carbon was added to the lanthanum-rich desorption solution for decolorization. After stirring for 30 min, impurities were removed and the solution was filtered. After filtration, 2.5 mol / L ammonia was slowly added to the filtrate to adjust the pH to 7.2, generating lanthanum hydroxide precipitate. The precipitate was filtered and washed until no chloride ions were present. It was then dried at 90 °C and calcined at 480 °C for 1.2 h to obtain lanthanum oxide product.

[0016] Example 2 A method for extracting lanthanum from claystone ion-adsorption rare earth elements using activated carbon based on baijiu (Chinese liquor) lees includes the following steps: S1, Preparation of activated carbon based on baijiu lees: Fresh baijiu lees are selected, impurities such as rice husks and stones are removed, and the lees are dried in an 80℃ oven until the moisture content is ≤10%. After pulverization, the lees are passed through an 80-mesh sieve to obtain lees powder. The lees powder is placed in a tube furnace under nitrogen protection and a stepped temperature control process is used. First, the temperature is increased to 400℃ at a rate of 5℃ / min for pre-carbonization and held for 0.5h. Then, the temperature is increased to 580℃ at a rate of 8℃ / min and held for carbonization for 1.5h. The carbonized lees powder is then naturally cooled to room temperature to obtain carbonized lees powder. The carbonized lees powder is then mixed with 4mol / L... The ZnCl2 activation solution was mixed at a material-to-liquid ratio of 1:3, ultrasonically impregnated at 300W for 2 hours, and then completely dried at 110℃. The mixture was then placed in a tube furnace and pre-activated at 600℃ under nitrogen protection by increasing the temperature at 5℃ / min and holding for 0.3 hours. The temperature was then increased to 850℃ at 6℃ / min for high-temperature activation for 1 hour. After cooling, the mixture was repeatedly washed with deionized water until the pH of the filtrate reached 6, and then dried at 100℃ to obtain a product with a specific surface area ≥1100 m². 2 / g, microporosity ≥78%, surface energy 42.5~48.3mJ / m 2 Activated carbon based on liquor lees.

[0017] S2, Pretreatment of clay rock rare earth ore: Take clay rock ion-adsorption type rare earth ore, crush it, pass it through a 40-mesh sieve, and air-dry it until the moisture content is ≤12% for later use; the mass content of lanthanum ion phase in clay rock ion-adsorption type rare earth ore is ≥0.08%; S3, Composite Leaching and Adsorption: The pretreated rare earth ore in S2 is mixed with distillers' grains-based activated carbon at a mass ratio of 5:1 and loaded into a column leaching device; a 0.2 mol / L ammonium sulfate leaching solution is prepared, the pH is adjusted to 5.0, and the solution is introduced into the column leaching device from top to bottom at a liquid-to-solid ratio of 3:1 and a flow rate of 2 mL / min. The leaching and adsorption are carried out at room temperature, and then the effluent is collected until the lanthanum concentration in the effluent is ≤0.01 g / L and then the flow is stopped. S4, activated carbon desorption: Take out the activated carbon from the distillers' grains after lanthanum adsorption, load it into the desorption column, use 0.5 mol / L hydrochloric acid solution as the desorbent, and pass it into the desorption column at a flow rate of 1.5 mL / min. Desorb at room temperature, collect the desorption solution, and stop when the lanthanum concentration in the desorption solution is ≤0.05 g / L to obtain lanthanum-rich desorption solution. S5, Lanthanum enrichment and purification: Add 1 g / L activated carbon to the lanthanum-rich desorption solution for decolorization, stir for 30 min, remove impurities and filter. After filtration, slowly add 2 mol / L ammonia water to the filtrate to adjust the pH to 7.0, generating lanthanum hydroxide precipitate. Filter and wash the precipitate until no chloride ions are present, dry at 80℃, and calcine at 450℃ for 1 h to obtain lanthanum oxide product.

[0018] Example 3 A method for extracting lanthanum from claystone ion-adsorption rare earth elements using activated carbon based on baijiu (Chinese liquor) lees includes the following steps: S1, Preparation of activated carbon based on baijiu lees: Fresh baijiu lees are selected, impurities such as rice husks and stones are removed, and the lees are dried in an oven at 100℃ until the moisture content is ≤10%. After pulverization, the lees are passed through a 90-mesh sieve to obtain fine lees powder. The lees powder is placed in a tube furnace under nitrogen inert gas protection and a stepped temperature control process is used. First, the temperature is increased to 380℃ at a heating rate of 4℃ / min for pre-carbonization and held for 0.5h. Then, the temperature is increased to 565℃ at a heating rate of 7℃ / min and held for carbonization for 2h. The carbonized lees powder is then naturally cooled to room temperature to obtain carbonized lees powder. The carbonized lees powder is then mixed with 6mol / L... The ZnCl2 activation solution was mixed at a material-to-liquid ratio of 1:5, ultrasonically impregnated at 400W for 3 hours, and completely dried at 120℃. It was then placed in a tube furnace and pre-activated at 600℃ under nitrogen protection, first at 5℃ / min for 0.3 hours, then at 10℃ / min for 1.5 hours of high-temperature activation at 830℃. After cooling, it was repeatedly washed with deionized water until the pH of the filtrate reached 7, and then dried at 100℃ to obtain a product with a specific surface area ≥1100 m². 2 / g, microporosity ≥78%, surface energy 42.5~48.3mJ / m 2 Activated carbon based on liquor lees.

[0019] S2, Pretreatment of clay rock rare earth ore: Take clay rock ion-adsorption type rare earth ore, crush it, pass it through a 60-mesh sieve, and air-dry it until the moisture content is ≤12% for later use; the mass content of lanthanum ion phase in clay rock ion-adsorption type rare earth ore is ≥0.08%; S3, Composite Leaching and Adsorption: The pretreated rare earth ore in S2 is mixed with distillers' grains-based activated carbon at a mass ratio of 8:1 and loaded into a column leaching device; a 0.3 mol / L ammonium sulfate leaching solution is prepared, the pH is adjusted to 5.5, and the solution is introduced into the column leaching device from top to bottom at a liquid-to-solid ratio of 4:1 and a flow rate of 3 mL / min. The leaching and adsorption are carried out at room temperature, and then the effluent is collected until the lanthanum concentration in the effluent is ≤0.01 g / L and then the flow is stopped. S4, activated carbon desorption: Take out the activated carbon from the distillers' grains after lanthanum adsorption, load it into the desorption column, use 0.8 mol / L hydrochloric acid solution as the desorbent, and pass it into the desorption column at a flow rate of 2 mL / min. Desorption is carried out at room temperature, and the desorption solution is collected until the lanthanum concentration in the desorption solution is ≤0.05 g / L, and then the process is stopped to obtain lanthanum-rich desorption solution. S5, Lanthanum enrichment and purification: 2 g / L activated carbon was added to the lanthanum-rich desorption solution for decolorization and impurity removal. After filtration, 3 mol / L ammonia was slowly added to the filtrate to adjust the pH to 7.5, generating lanthanum hydroxide precipitate. The precipitate was filtered and washed until no chloride ions were present, dried at 90℃, and calcined at 500℃ for 1.5 h to obtain lanthanum oxide product.

[0020] Comparative Example Rare earth ore from the same batch as in Example 1 was selected, and a traditional ammonium sulfate leaching-oxalic acid precipitation process was adopted: conventional column leaching with 0.25 mol / L ammonium sulfate was performed, and oxalic acid was added to precipitate the leachate, followed by calcination to prepare lanthanum oxide. The purity of lanthanum oxide was found to be 85.3%, the total recovery rate of lanthanum was 78.6%, and the discharge of ammonia nitrogen wastewater was large with high impurity content.

[0021]

[0022] The comparative data above demonstrate that, compared to the traditional ammonium sulfate leaching-oxalic acid precipitation process and the original single isothermal preparation process, the optimized stepped temperature-controlled preparation process of this invention has significant advantages. Through a temperature optimization scheme involving segmented pre-carbonization and gradient high-temperature activation, the defects of traditional isothermal pyrolysis, such as pore collapse, loss of surface functional groups, and insufficient surface activity, are improved. The specific surface area of ​​the prepared distillers' grains-based activated carbon is significantly increased to 1120–1210 m². 2 / g, with a stable microporosity of ≥78% and a surface energy precisely increased to 42.5–48.3 mJ / m 2 Compared to traditional activated carbon, this method improves efficiency by over 50%. The ultra-high specific surface area provides ample adsorption sites, significantly increasing the lanthanum adsorption capacity. The high surface energy significantly enhances the activity of functional groups on the activated carbon surface, greatly enhancing the selective chemisorption capacity for lanthanum ions and effectively suppressing the co-adsorption of iron and aluminum impurities. In the optimized three sets of examples, the total lanthanum recovery rate remained consistently above 93%, reaching a maximum of 95.3%, an improvement of over 16 percentage points compared to the traditional process. The purity of the lanthanum oxide product was consistently no less than 95.2%, reaching a maximum of 96.8%, demonstrating a significant improvement in impurity retention. Simultaneously, the optimized process further reduces the consumption of ineffective reagents, and the discharge of ammonia nitrogen wastewater is reduced by more than 30% compared to the traditional process, representing a significant technological advancement distinct from existing technologies.

[0023] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for extracting lanthanum from claystone ion-adsorption rare earth elements using activated carbon based on liquor lees, characterized in that... Includes the following steps: S1, Preparation of activated carbon based on baijiu lees: After removing impurities from baijiu lees, dry, crush, and sieve to obtain lees powder; carbonize the lees powder under nitrogen protection to obtain carbonized lees powder; mix the carbonized lees powder with zinc chloride activation solution, ultrasonically impregnate, dry, activate, wash with water, and dry to obtain activated carbon based on baijiu lees. S2, Pretreatment of clay rock rare earth ore: Take clay rock ion-adsorption type rare earth ore, crush it, sieve it and air dry it for later use; the mass content of lanthanum ion phase in clay rock ion-adsorption type rare earth ore is ≥0.08%; S3, Composite Leaching and Adsorption: The pretreated rare earth ore in S2 is mixed with distillers' grains-based activated carbon at a mass ratio of 5~8:1 and loaded into a column leaching device; a 0.2~0.3mol / L ammonium sulfate leaching solution is prepared, the pH is adjusted to 5.0~5.5, and the solution is introduced into the column leaching device from top to bottom at a liquid-to-solid ratio of 3~4:1 and a flow rate of 2~3mL / min. The leaching and adsorption integrated reaction is carried out at room temperature, and then the effluent is collected until the lanthanum concentration in the effluent is ≤0.01g / L and the flow is stopped. S4, activated carbon desorption: Take out the distillers' grains-based activated carbon after lanthanum adsorption, load it into the desorption column, use 0.5~0.8mol / L hydrochloric acid solution as desorbent, and pass it into the desorption column at a flow rate of 1.5~2mL / min. Desorb at room temperature, collect the desorption solution, and stop when the lanthanum concentration in the desorption solution is ≤0.05g / L to obtain lanthanum-rich desorption solution; S5, Lanthanum enrichment and purification: Add 1~2g / L activated carbon to the lanthanum-rich desorption solution for decolorization and impurity removal. After filtration, slowly add 2~3mol / L ammonia water to the filtrate to adjust the pH to 7.0~7.5, and lanthanum hydroxide precipitate will be generated. The precipitate is filtered and washed until it is free of chloride ions, dried at 80~90℃, and calcined at 450~500℃ for 1~1.5h to obtain lanthanum oxide product.

2. The method for extracting lanthanum from claystone ion-adsorption rare earth elements using activated carbon based on liquor lees according to claim 1, characterized in that: In step S1, the baijiu lees are dried at 80~100℃ until the moisture content is ≤10%, and an 80~100 mesh sieve is used for sieving. Using a stepped temperature control process, the temperature is first raised to 350~400℃ at a rate of 3~5℃ / min under a nitrogen atmosphere for pre-carbonization, and then held for 0.5h. Then the temperature is raised to 550~580℃ at a rate of 5~8℃ / min for main carbonization, and then held for 1.5~2h.

3. The method for extracting lanthanum from claystone ion-adsorption rare earth elements using activated carbon based on liquor lees according to claim 2, characterized in that: In step S1, the concentration of the zinc chloride activation solution is 4-6 mol / L, the mass-to-volume ratio of carbonized distiller's grains powder to zinc chloride activation solution is 1:3-5, the ultrasonic impregnation power is 300-400W, the impregnation time is 2-3 hours, and the drying temperature after impregnation is 110-120℃.

4. The method for extracting lanthanum from claystone ion-adsorption rare earth elements using activated carbon based on liquor lees according to claim 3, characterized in that: During activation in step S1, in a nitrogen atmosphere, the temperature is first raised to 600℃ at a rate of 5℃ / min for pre-activation and held for 0.3h, and then raised to the activation temperature of 820~850℃ at a rate of 6~10℃ / min for activation and held for 1~1.5h. After activation, the solution is washed with water until the pH of the filtrate is 6-7, yielding a product with a specific surface area ≥1100 m². 2 / g, microporosity ≥78%, surface energy 42.5~48.3mJ / m 2 Activated carbon based on liquor lees.

5. The method for extracting lanthanum from claystone ion-adsorption rare earth elements using activated carbon based on liquor lees according to claim 4, characterized in that: In step S2, the clay rock ion adsorption type rare earth ore is crushed, passed through a 40-60 mesh sieve, and air-dried until the moisture content is ≤15%.

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