Method for efficiently removing beryllium and thallium in lithium residue

Abstract

The application provides a method for efficiently removing beryllium and thallium in lithium residue, comprising the following steps: S1, providing lithium residue; the lithium residue contains beryllium and thallium, and the lithium residue has calcium aluminosilicate; S2, performing hydrothermal treatment on the lithium residue and an acid solution to obtain a reaction liquid; the acid solution comprises one or more of sulfuric acid solution, hydrochloric acid solution, nitric acid solution and phosphoric acid solution; the concentration of the acid solution is not less than 1 mol / L; the temperature of the hydrothermal treatment is not less than 100 DEG C, and the time of the hydrothermal treatment is not less than 2 h; and S3, performing solid-liquid separation on the reaction liquid to obtain a beryllium and thallium separation liquid and a detoxification residue. The application has excellent removal effect on beryllium and thallium in lithium residue, and can realize low-cost detoxification and reuse of the lithium residue.

Description

Technical Field

[0001] This invention relates to the field of industrial hazardous solid waste treatment, and in particular to a method for efficiently removing beryllium and thallium from lithium slag. Background Technology

[0002] With global demand for lithium increasing year by year, lithium resources are showing a trend of supply falling short of demand. The new energy industry, in particular, has a significant demand for lithium. Lithium resources are mainly extracted from lithium ores such as lepidolite through smelting. Related lithium extraction processes include acid extraction, alkaline extraction, and salt extraction; currently, relevant companies mainly use the salt roasting method for lithium extraction. The main process involves mixing sulfate with lepidolite and roasting it at temperatures above 900℃ to change or destroy the crystal structure of the lepidolite. The cations in the salt exchange ions with lithium ions, transforming the lithium from a solid silicate state into a soluble lithium salt, which is then leached into the liquid phase.

[0003] In the aforementioned lithium extraction process using sulfate roasting, the addition of large amounts of sulfates and other auxiliary materials results in a significant amount of waste residue after roasting and leaching. Statistics show that nearly 30 tons of waste residue are generated for every ton of lithium produced. Simultaneously, toxic metals such as beryllium and thallium participate in the lithium ore formation process as trace mineralizing elements, and most of these end up in the waste residue after smelting. The beryllium and thallium elements in the waste residue are unstable and can enter the surrounding environment through rainfall, sunlight, and other processes, causing environmental pollution.

[0004] Therefore, it is necessary to provide an efficient method for removing beryllium and thallium from lithium slag in order to solve or at least alleviate the technical problem of environmental hazards caused by beryllium and thallium in lithium slag. Summary of the Invention

[0005] The main objective of this invention is to provide a method for efficiently removing beryllium and thallium from lithium slag, thereby solving the technical problem of environmental hazards caused by beryllium and thallium in lithium slag.

[0006] To achieve the above objectives, the present invention provides a method for efficiently removing beryllium and thallium from lithium slag, comprising the following steps:

[0007] S1, providing lithium slag; the lithium slag contains beryllium and thallium, and the lithium slag contains calcium aluminosilicate;

[0008] S2, the lithium slag and acid solution are subjected to hydrothermal treatment to obtain a reaction solution;

[0009] The acid solution includes one or more of sulfuric acid solution, hydrochloric acid solution, nitric acid solution, and phosphoric acid solution; the concentration of the acid solution is not less than 1 mol / L; the temperature of the hydrothermal treatment is not less than 100℃, and the duration of the hydrothermal treatment is not less than 2 hours.

[0010] S3, perform solid-liquid separation on the reaction solution to obtain beryllium-thallium separation solution and detoxification residue.

[0011] Furthermore, step S1 also includes grinding the lithium slag.

[0012] Furthermore, the lithium slag contains 20-80 mg / kg of beryllium and 20-80 mg / kg of thallium.

[0013] Furthermore, the lithium slag contains 50-55% calcium aluminosilicate by mass.

[0014] The lithium slag also contains calcium fluoride, calcium sulfate dihydrate, and iron silicate; in the lithium slag, the mass percentage of calcium fluoride is 5-8%, the mass percentage of calcium sulfate dihydrate is 18-23%, and the mass percentage of iron silicate is 13-18%.

[0015] Furthermore, the temperature of the hydrothermal treatment is 100-260℃.

[0016] Furthermore, the temperature of the hydrothermal treatment is 140-160℃.

[0017] Furthermore, the duration of the hydrothermal treatment is 2-5 hours.

[0018] Furthermore, the acid solution is a nitric acid solution or a phosphoric acid solution.

[0019] Furthermore, the concentration of the acid solution is 1-5 mol / L.

[0020] Furthermore, the mass-to-volume ratio of the lithium slag to the acid solution is 1g:5-100mL.

[0021] Compared with the prior art, the present invention has at least the following advantages:

[0022] This invention provides a highly efficient method for removing beryllium and thallium from lithium slag, addressing the environmental hazards caused by these elements. This method offers a simpler and more efficient treatment approach, removing beryllium and thallium from lithium slag and enabling low-cost detoxification and reuse. Specifically, this invention exhibits excellent removal efficiency for beryllium and thallium in lithium slag, with the final detoxification product being recyclable. By adding specific acid solutions such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid to the lithium slag, and then subjecting the slag and acid solutions to hydrothermal treatment, the structure of calcium-containing phases such as calcium aluminosilicate in the lithium slag can be disrupted. These calcium-containing phases are transformed into calcium sulfate, calcium silicate, calcium hydrogen phosphate, and silicon dioxide phases, achieving efficient release of beryllium and thallium. This provides a novel method for effectively removing beryllium and thallium from lithium slag. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 The XRD patterns of lithium slag in Examples 1-6 and Comparative Examples 1-4 of this invention;

[0025] Figure 2 The XRD pattern of the detoxified residue in Embodiment 1 of the present invention;

[0026] Figure 3 The XRD pattern of the detoxified residue in Example 3 of this invention;

[0027] Figure 4 The XRD pattern of the detoxified residue in Example 4 of this invention;

[0028] Figure 5 This is the XRD pattern of the detoxified residue in Embodiment 5 of the present invention.

[0029] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0032] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of this invention, can be used to implement this invention using any prior art methods, devices, and materials similar to or equivalent to those described, used, or made of materials in the embodiments of this invention. In the embodiments and comparative examples of this invention, the lithium slag used is from the same source and from the same batch.

[0033] It should be noted that the current treatment methods for leached lithium slag include: 1) complexation treatment, such as a method for treating heavy metals in lithium ore tailings disclosed in Chinese Patent Publication No. CN118045850A; 2) stabilization treatment, such as a method for harmless treatment of lithium slag to remove thallium and beryllium disclosed in Chinese Patent Publication No. CN118558703A, and a beryllium ultra-stable mineralizing reagent and a method for ultra-stable mineralization of dangerous beryllium elements in lithium slag disclosed in Chinese Patent Publication No. CN116966470A. 3) Chemical leaching treatment, such as the leaching agent and its application for removing thallium and beryllium from lithium slag disclosed in Chinese Patent Publication No. CN119351786A; 4) Calcination leaching treatment, such as a method for harmless treatment of lithium slag and preparation of water-stabilized materials from treated lithium slag disclosed in Chinese Patent Publication No. CN119241158A; 5) Bioleaching mineralization treatment: such as a method and apparatus for treating thallium-containing lithium slag based on chemical leaching and biomineralization disclosed in Chinese Patent Publication No. CN119101811A. The above methods leach or stabilize lithium slag by crushing, adding chemicals, or microorganisms. The treatment steps are complex, multiple chemicals are added in large quantities, resulting in high lithium slag treatment costs, and the leaching products are often disposed of as waste.

[0034] This invention provides a method for efficiently removing beryllium and thallium from lithium slag, thereby addressing the environmental hazards caused by beryllium and thallium in lithium slag. This method offers a simpler and more efficient treatment approach, enabling low-cost detoxification and reuse of lithium slag.

[0035] As an illustration of the technical solution of the present invention, the present invention provides a method for efficiently removing beryllium and thallium from lithium slag, comprising the following steps:

[0036] S1 provides lithium slag; the lithium slag contains beryllium and thallium, and the lithium slag contains calcium aluminosilicate.

[0037] In this step, the lithium slag is ground before being provided; and the lithium slag is dried before grinding. Specifically, the lithium slag is dried and ground; after grinding, there are no obvious lumpy particles in the lithium slag; the drying temperature is 40-100℃, and further 40-80℃; the drying is carried out in a forced-air drying oven, and the grinding is carried out in a mortar.

[0038] The lithium slag contains beryllium at a content of 20-80 mg / kg, more specifically 40-80 mg / kg; and thallium at a content of 20-80 mg / kg, more specifically 20-40 mg / kg. In the lithium slag of this invention, calcium aluminosilicate accounts for more than 40% by mass, more specifically 50-55% by mass; the lithium slag also contains calcium fluoride, calcium sulfate dihydrate, and ferrosilicon; in the lithium slag, calcium fluoride accounts for 5-8% by mass, calcium sulfate dihydrate accounts for 18-23% by mass, and ferrosilicon accounts for 13-18% by mass. In this invention, the lithium slag is obtained by leaching lithium from lepidolite after sulfate roasting, with the leaching primarily being water leaching.

[0039] S2, the lithium slag and acid solution are subjected to hydrothermal treatment together to obtain a reaction solution.

[0040] In this invention, the acid solution includes one or more of sulfuric acid solution, hydrochloric acid solution, nitric acid solution, and phosphoric acid solution. Further, the acid solution includes one or more of sulfuric acid solution, nitric acid solution, and phosphoric acid solution; alternatively, the acid solution can be sulfuric acid solution, nitric acid solution, or phosphoric acid solution. When the acid solution is sulfuric acid solution, the detoxification effect is excellent, and there are fewer impurity peaks in the phase analysis of the detoxified residue, resulting in high phase purity of calcium sulfate. In some cases, due to the high hazard and strong corrosiveness of sulfuric acid, there are very high requirements for transportation, storage, and operation. Further, the acid solution can be nitric acid solution or phosphoric acid solution. This invention can use nitric acid solution or phosphoric acid solution to replace sulfuric acid solution, or further use phosphoric acid solution to replace sulfuric acid solution. Unexpectedly, compared with sulfuric acid solution, the beryllium and thallium removal rate of nitric acid solution did not decrease; compared with sulfuric acid solution and nitric acid solution, the removal rate of beryllium and thallium by phosphoric acid solution can also reach over 90%.

[0041] In this invention, the concentration of the acid solution is not less than 1 mol / L; the concentration of the acid solution is the concentration of the acidic substance in the acid solution, such as sulfuric acid, hydrochloric acid, phosphoric acid, or nitric acid. Preferably, the concentration of the acid solution is 1-5 mol / L, more preferably 1.5-4 mol / L; as an example, when the acid solution is a sulfuric acid solution, the concentration of the acid solution is 1.5-18.4 mol / L; when the acid solution is a nitric acid solution or a hydrochloric acid solution, the concentration of the acid solution is 3.5-4 mol / L; when the acid solution is a phosphoric acid solution, the concentration of the acid solution is 1.8-3 mol / L, more preferably 1.8-2.2 mol / L.

[0042] In this invention, the mass-to-volume ratio of the lithium slag to the acid solution is no greater than 1g:5mL; specifically, the mass-to-volume ratio of the lithium slag to the acid solution is 1g:5-100mL, further being 1g:8-60mL, 1g:10-60mL, 1g:10-50mL, 1g:8-15mL, or 1g:40-60mL.

[0043] In this invention, the temperature of the hydrothermal treatment is not lower than 100℃, further 100-260℃, further 140-210℃, and further 140-160℃ to reduce energy consumption. The duration of the hydrothermal treatment is not less than 2 hours; further 2-5 hours, further 2-4 hours, further 3-4 hours; the duration of the hydrothermal treatment can also be not less than 3 hours. In this invention, a hydrothermal reaction occurs during the hydrothermal treatment process; the hydrothermal treatment is carried out in a hydrothermal reactor.

[0044] S3, perform solid-liquid separation on the reaction solution to obtain beryllium-thallium separation solution and detoxification residue.

[0045] In this step, before performing the solid-liquid separation, the product after hydrothermal treatment is cooled at room temperature and cooled to room temperature; in this invention, the solid-liquid separation method includes centrifugal separation.

[0046] Specifically, this invention relates to a method for efficiently removing beryllium and thallium from lithium slag. First, the lithium slag to be treated is dried and ground. Then, the ground lithium slag is placed in a hydrothermal reactor, a specific acid is added, and a hydrothermal reaction is carried out. Finally, the products after the hydrothermal reaction are sequentially cooled and subjected to solid-liquid separation to obtain a separated liquid and a solid residue. This invention, through the addition of an acid, hydrothermal treatment, and solid-liquid separation, can efficiently remove beryllium and thallium from lithium slag. Specifically, this invention adds a specific acid to the beryllium and thallium-containing lithium slag to provide a specific acidic environment, controls the liquid-to-solid ratio, and then carries out a hydrothermal reaction. Finally, solid-liquid separation is performed to obtain detoxified products—calcium sulfate, calcium silicate, calcium hydrogen phosphate, silicon dioxide, and other solids—as well as beryllium and thallium extracts.

[0047] This invention first adds a specific acidic agent to the aluminum-lithium slag, and then further treats it by hydrothermal method to destroy the structure of calcium-containing phases such as calcium aluminosilicate in the slag, so that the calcium-containing phases are transformed into calcium sulfate, calcium silicate, calcium hydrogen phosphate and silicon dioxide, etc., to achieve the effect of efficiently releasing beryllium and thallium elements, and provides a new method for effectively removing beryllium and thallium elements from lithium slag.

[0048] The main chemical reaction formulas involved in this invention include:

[0049] 4H2SO4+Ca(Al2Si2O8)=CaSO4+Al2(SO4)3+2SiO2+4H2O;

[0050] 6HNO3+Ca(Al2Si2O8)=CaSiO3+2Al(NO3)3+SiO2+3H2O;

[0051] 8HCl+Ca(Al2Si2O8)=CaCl2+2AlCl3+2SiO2+4H2O;

[0052] H3PO4+Ca(Al2Si2O8)=CaHPO4+Al2O3+2SiO2+H2O.

[0053] The following are specific examples of the present invention:

[0054] Example 1

[0055] A method for removing beryllium and thallium from lithium slag comprises the following steps:

[0056] 1. Take lithium slag from a certain company.

[0057] 2. The above lithium slag is dried and ground at 60°C. After grinding, there are no obvious lumpy particles in the lithium slag.

[0058] The lithium slag was tested, and the contents of Be and Tl in the lithium slag of Examples 1-6 and Comparative Examples 1-4 were 70.3 mg / kg and 22.8 mg / kg, respectively; see [link to relevant documentation]. Figure 1 As shown, lithium slag contains calcium aluminosilicate, calcium fluoride, calcium sulfate dihydrate, and ferrosilicon. The mass percentages of calcium aluminosilicate, calcium fluoride, calcium sulfate dihydrate, and ferrosilicon in lithium slag are 52.9%, 6.3%, 20.7%, and 15.3%, respectively.

[0059] 3. Place 1 kg of ground lithium slag into a hydrothermal reactor, add 10 L of 1.8 mol / L sulfuric acid solution, with a liquid-to-solid ratio of 10:1, and hydrothermally react at 150℃ for 3 h to obtain the reaction solution.

[0060] 4. Cool the reaction solution at room temperature and centrifuge to obtain a beryllium-thallium-containing separation solution and a detoxified residue; see [link to relevant documentation]. Figure 2 As shown, the detoxification products in the detoxification residue are mainly calcium sulfate and silicon dioxide.

[0061] The beryllium content in the separation solution was determined to be 6.82 mg / L and the thallium content was 2.08 mg / L. The calculated beryllium removal rate was approximately 97% and the thallium removal rate was approximately 91%.

[0062] Example 2

[0063] A method for removing beryllium and thallium from lithium slag comprises the following steps:

[0064] 1. Take lithium slag from a certain company (same as in Example 1).

[0065] 2. The above lithium slag is dried and ground at 60°C. After grinding, there are no obvious lumpy particles in the lithium slag.

[0066] 3. Place 1 kg of ground lithium slag into a hydrothermal reactor, add 50 L of 1.8 mol / L sulfuric acid solution, with a liquid-to-solid ratio of 50:1, and hydrothermally react at 150 °C for 3 h to obtain the reaction solution.

[0067] 4. Cool the reaction solution at room temperature and centrifuge to obtain a beryllium-thallium separation solution and a detoxified residue.

[0068] The beryllium content in the separation solution was determined to be 1.39 mg / L and the thallium content was 0.42 mg / L. The calculated beryllium removal rate was approximately 99% and the thallium removal rate was approximately 92%.

[0069] Example 3

[0070] A method for removing beryllium and thallium from lithium slag comprises the following steps:

[0071] 1. Take lithium slag from a certain company (same as in Example 1).

[0072] 2. The above lithium slag is dried and ground at 60°C. After grinding, there are no obvious lumpy particles in the lithium slag.

[0073] 3. Place 1 kg of ground lithium slag into a hydrothermal reactor, add 10 L of 3.6 mol / L nitric acid solution, with a liquid-to-solid ratio of 10:1, and hydrothermally react at 150 °C for 3 h to obtain the reaction solution.

[0074] 4. Cool the reaction solution at room temperature and centrifuge to obtain a beryllium-thallium-containing separation solution and a detoxified residue; see [link to relevant documentation]. Figure 3 As shown, the detoxification products in the detoxification residue are mainly calcium silicate and silicon dioxide.

[0075] The beryllium content in the separation solution was determined to be 7.01 mg / L and the thallium content was 2.10 mg / L. The calculated beryllium removal rate was approximately 99% and the thallium removal rate was approximately 92%.

[0076] Example 4

[0077] A method for removing beryllium and thallium from lithium slag comprises the following steps:

[0078] 1. Take lithium slag from a certain company (same as in Example 1).

[0079] 2. The above lithium slag is dried and ground at 60°C. After grinding, there are no obvious lumpy particles in the lithium slag.

[0080] 3. Place 1 kg of ground lithium slag into a hydrothermal reactor, add 10 L of 3.6 mol / L hydrochloric acid solution, with a liquid-to-solid ratio of 10:1, and perform a hydrothermal reaction at 150℃ for 3 h to obtain the reaction solution.

[0081] 4. Cool the reaction solution at room temperature and centrifuge to obtain a beryllium-thallium-containing separation solution and a detoxified residue; see [link to relevant documentation]. Figure 4 As shown, the detoxification product in the detoxification residue is mainly silicon dioxide.

[0082] The beryllium content in the separation solution was determined to be 6.82 mg / L and the thallium content was 1.82 mg / L. The calculated beryllium removal rate was approximately 97% and the thallium removal rate was approximately 80%.

[0083] Example 5

[0084] A method for removing beryllium and thallium from lithium slag comprises the following steps:

[0085] 1. Take lithium slag from a certain company (same as in Example 1).

[0086] 2. The above lithium slag is dried and ground at 60°C. After grinding, there are no obvious lumpy particles in the lithium slag.

[0087] 3. Place 1 kg of ground lithium slag into a hydrothermal reactor, add 10 L of 2 mol / L phosphoric acid solution, with a liquid-to-solid ratio of 10:1, and hydrothermally react at 150℃ for 3 h to obtain the reaction solution.

[0088] 4. Cool the reaction solution at room temperature and centrifuge to obtain a beryllium-thallium-containing separation solution and a detoxified residue; see [link to relevant documentation]. Figure 5 As shown, the detoxification products in the detoxification residue are mainly dicalcium phosphate, calcium fluoride and silicon dioxide.

[0089] The beryllium content in the separation solution was determined to be 6.54 mg / L and the thallium content was 2.26 mg / L. The calculated beryllium removal rate was approximately 93% and the thallium removal rate was approximately 99%.

[0090] Example 6

[0091] A method for removing beryllium and thallium from lithium slag comprises the following steps:

[0092] 1. Take lithium slag from a certain company (same as in Example 1).

[0093] 2. The above lithium slag is dried and ground at 60°C. After grinding, there are no obvious lumpy particles in the lithium slag.

[0094] 3. Place 1 kg of ground lithium slag into a hydrothermal reactor, add 10 L of 1.8 mol / L sulfuric acid solution, with a liquid-to-solid ratio of 10:1, and perform a hydrothermal reaction at 200℃ for 3 h to obtain the reaction solution.

[0095] 4. Cool the reaction solution at room temperature and centrifuge to obtain a beryllium-thallium separation solution and a detoxified residue.

[0096] The beryllium content in the separation solution was determined to be 7.02 mg / L and the thallium content was 2.07 mg / L. The calculated beryllium removal rate was approximately 99% and the thallium removal rate was approximately 91%.

[0097] Comparative Example 1

[0098] A method for removing beryllium and thallium from lithium slag comprises the following steps:

[0099] 1. Take lithium slag from a certain company (same as in Example 1).

[0100] 2. The above lithium slag is dried and ground at 60°C. After grinding, there are no obvious lumpy particles in the lithium slag.

[0101] 3. Place 1 kg of ground lithium slag into a hydrothermal reactor, add 50 L of water, with a liquid-to-solid ratio of 50:1, and hydrothermally react at 150 °C for 3 h to obtain the reaction solution.

[0102] 4. Cool the reaction solution at room temperature and centrifuge to obtain the separation liquid and separation residue.

[0103] The beryllium content in the separation solution was determined to be 0.84 μg / L and the thallium content was 3.28 μg / L. The calculated beryllium removal rate was approximately 0.06% and the thallium removal rate was approximately 0.72%.

[0104] Comparative Example 2

[0105] A method for removing beryllium and thallium from lithium slag comprises the following steps:

[0106] 1. Take lithium slag from a certain company (same as in Example 1).

[0107] 2. The above lithium slag is dried and ground at 60°C. After grinding, there are no obvious lumpy particles in the lithium slag.

[0108] 3. Place 1 kg of ground lithium slag into a hydrothermal reactor, add 10 L of 2 mol / L boric acid solution, with a liquid-to-solid ratio of 10:1, and hydrothermally react at 150℃ for 3 h to obtain the reaction solution.

[0109] 4. Cool the reaction solution at room temperature and centrifuge to obtain the separation liquid and separation residue.

[0110] The beryllium content in the separation solution was determined to be 28 μg / L and the thallium content was 23 μg / L. The calculated beryllium removal rate was approximately 0.4% and the thallium removal rate was approximately 1%.

[0111] Comparative Example 3

[0112] A method for removing beryllium and thallium from lithium slag comprises the following steps:

[0113] 1. Take lithium slag from a certain company (same as in Example 1).

[0114] 2. The above lithium slag is dried and ground at 60°C. After grinding, there are no obvious lumpy particles in the lithium slag.

[0115] 3. Add 10L of 1.8mol / L sulfuric acid solution to 1kg of ground lithium slag, with a liquid-to-solid ratio of 10:1, and react at 25℃ for 3h to obtain the reaction solution.

[0116] 4. Centrifuge the reaction solution to obtain the separation liquid and the separation residue.

[0117] The beryllium content in the separation solution was determined to be 4.57 mg / L and the thallium content was 1.19 mg / L. The calculated beryllium removal rate was approximately 65% ​​and the thallium removal rate was approximately 52%.

[0118] Comparative Example 4

[0119] A method for removing beryllium and thallium from lithium slag comprises the following steps:

[0120] 1. Take lithium slag from a certain company (same as in Example 1).

[0121] 2. The above lithium slag is dried and ground at 60°C. After grinding, there are no obvious lumpy particles in the lithium slag.

[0122] 3. Place 1 kg of ground lithium slag into a hydrothermal reactor, add 10 L of 1.8 mol / L sulfuric acid solution, with a liquid-to-solid ratio of 10:1, and react at 80 °C for 3 h to obtain the reaction solution.

[0123] 4. Cool the reaction solution at room temperature and centrifuge to obtain the separation liquid and separation residue.

[0124] The beryllium content in the separation solution was determined to be 4.99 mg / L and the thallium content was 1.37 mg / L. The calculated beryllium removal rate was approximately 71% and the thallium removal rate was approximately 60%.

[0125] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for efficiently removing beryllium and thallium from lithium slag, characterized in that, Including the following steps: S1 provides lithium slag; the lithium slag contains beryllium and thallium, with beryllium content of 20-80 mg / kg and thallium content of 20-80 mg / kg; the lithium slag contains calcium aluminosilicate, with calcium aluminosilicate accounting for 50-55% by mass; S2, the lithium slag and acid solution are subjected to hydrothermal treatment to obtain a reaction solution; the mass-to-volume ratio of the lithium slag and the acid solution is 1g:5-100mL. The acid solution is one of sulfuric acid solution, nitric acid solution, and phosphoric acid solution; When the acid solution is a sulfuric acid solution, the concentration of the acid solution is 1.5-18.4 mol / L, and the reaction involved includes 4H2SO4+Ca(Al2Si2O8)=CaSO4+Al2(SO4)3+2SiO2+4H2O; When the acid solution is a nitric acid solution, the concentration of the acid solution is 3.5-4 mol / L, and the reaction involved includes 6HNO3+Ca(Al2Si2O8)=CaSiO3+2Al(NO3)3+SiO2+3H2O; When the acid solution is a phosphoric acid solution, the concentration of the acid solution is 1.8-3 mol / L, and the reaction involved includes H3PO4 + Ca(Al2Si2O8) = CaHPO4 + Al2O3 + 2SiO2 + H2O; The hydrothermal treatment temperature is 140-210℃, and the hydrothermal treatment duration is 2-5 hours; S3, perform solid-liquid separation on the reaction solution to obtain beryllium-thallium separation solution and detoxification residue.

2. The method for efficiently removing beryllium and thallium from lithium slag according to claim 1, characterized in that, Step S1 further includes grinding the lithium slag.

3. The method for efficiently removing beryllium and thallium from lithium slag according to claim 1, characterized in that, The lithium slag also contains calcium fluoride, calcium sulfate dihydrate, and iron silicate; in the lithium slag, the mass percentage of calcium fluoride is 5-8%, the mass percentage of calcium sulfate dihydrate is 18-23%, and the mass percentage of iron silicate is 13-18%.

4. The method for efficiently removing beryllium and thallium from lithium slag according to claim 1, characterized in that, The temperature of the hydrothermal treatment is 140-160℃.

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