Method for inhibiting beryllium leaching from lithium smelter slag

Abstract

This application discloses a method for inhibiting beryllium leaching from lithium smelting slag. The method includes the following steps: mixing a solidification and stabilizing agent with lithium smelting slag through ball milling, resulting in a beryllium leaching concentration in the treated lithium smelting slag that meets national standards. This treatment method can be directly carried out on existing lithium smelting processes. The solidification and stabilizing agent includes a calcium-containing compound, which includes at least one of calcium phosphate, calcium sulfate, calcium carbonate, and calcium hydroxide. This application is based on the principle of composite beryllium solidification through lattice substitution and adsorption. After treating beryllium-containing lithium smelting slag with this agent, the beryllium in the treated lithium smelting slag can be stabilized and solidified. Furthermore, the solidification and stabilizing agent in this application can be general industrial solid waste, with a wide range of raw material sources, simple operation, significant effects, and easy large-scale application. It is of great significance for the harmless disposal and resource utilization of highly toxic lithium slag, using waste to treat waste.

Description

Technical Field

[0001] This application belongs to the field of harmless treatment technology of lithium smelting slag, specifically relating to a method for inhibiting beryllium leaching from lithium smelting slag. Background Technology

[0002] Lithium smelting slag, especially the waste residue generated after sulfate roasting and leaching of lithium from lepidolite ore, has become a major environmental challenge. With the rapid development of the new energy industry, the demand for lithium carbonate is constantly increasing, resulting in tens of millions of tons of lithium smelting slag produced annually. This waste residue contains toxic heavy metals such as thallium, beryllium, rubidium, and cesium, which can leach and seep through rainwater and other pathways, causing serious pollution to soil and groundwater. Currently, the mainstream treatment approach involves deep removal of these toxic heavy metals through field treatment and mild acid treatment, but beryllium treatment is particularly difficult. Due to its unique properties, beryllium is difficult to completely remove, and even after deep removal treatment, the beryllium that is difficult to leach in lithium smelting slag is actually activated, with leaching concentrations potentially reaching tens or even hundreds of micrograms per liter, far exceeding national standards. This indicates that existing technologies have significant shortcomings in treating beryllium in lithium smelting slag, and there is an urgent need to develop new and effective methods to stabilize and solidify beryllium in lithium smelting slag to reduce its leaching toxicity to levels that meet national standards. Summary of the Invention

[0003] In view of this, this application provides a method for inhibiting beryllium leaching from lithium smelting slag. This method effectively stabilizes and solidifies the beryllium in the treated lithium smelting slag, ensuring that the beryllium leaching concentration is reduced to below the standard specified in the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB 5085.3—2007), thus meeting national environmental protection requirements. Furthermore, the stabilizing agent used in this application is a general industrial solid waste, with widely available and low-cost raw materials, and possesses the advantage of resource recycling, achieving both environmental and economic benefits.

[0004] In a first aspect, a method for suppressing beryllium leaching from lithium smelting slag, the method comprising the following steps:

[0005] S1. The solidification and stabilizing agent is mixed with lithium smelting slag to obtain a mixture.

[0006] S2. The mixture described in step S1 is ball-milled;

[0007] Steps S1 and S2 can be performed directly in the existing lithium smelting process.

[0008] The curing and stabilizing agent mentioned in step S1 includes a calcium-containing compound;

[0009] The calcium-containing compound includes at least one of calcium phosphate, calcium sulfate, calcium carbonate, and calcium hydroxide.

[0010] By adopting the above technical solution, this application provides a method for inhibiting beryllium leaching from lithium smelting slag, which solves the problem of beryllium leaching from lithium smelting slag. The calcium-containing compound in this application can effectively fix beryllium in lithium smelting slag through lattice substitution and adsorption, reducing its leaching risk; furthermore, the entire process is simple and easy to implement, facilitating large-scale application. In summary, this application provides a highly efficient and easy-to-operate method for inhibiting beryllium leaching from lithium smelting slag, which is of great significance for the harmless disposal of highly toxic lithium slag.

[0011] Optionally, the ratio of the amount of the calcium-containing compound to the amount of the lithium smelting slag is 1:(0.2-200).

[0012] Optionally, the solidification and stabilizing agent is derived from industrial solid waste; the industrial solid waste includes at least one of waste gypsum, wastewater neutralization slag, carbide slag, desulfurization gypsum slag, and phosphogypsum.

[0013] By adopting the above technical solution, the solidification and stabilization agent in this application is derived from industrial solid waste. This measure not only effectively solves the leaching problem of beryllium in lithium smelting slag but also realizes the resource utilization of industrial solid waste, achieving both environmental and economic benefits. Using industrial solid waste as the agent not only provides a wide range of raw material sources and low costs but also reduces secondary pollution and promotes resource recycling. This makes the entire treatment process more economical and feasible, and also aligns with the concept of sustainable development. In summary, this technical solution significantly improves the efficiency and environmental performance of lithium smelting slag treatment, and is of great significance for the harmless disposal and resource utilization of highly toxic lithium slag. Furthermore, the solidification and stabilization agent used is derived from industrial solid waste, which has a wide range of raw material sources and low costs, reducing treatment costs. At the same time, using industrial solid waste as the agent realizes resource recycling, reduces secondary pollution, and further enhances environmental protection effects.

[0014] Further optionally, the weight of the solidification and stabilizing agent in step S1 is negatively correlated with the content of calcium-containing compounds in the solid waste;

[0015] When the calcium content in the industrial solid waste is not less than 60%, the weight of the solidification and stabilization agent is w of the weight of the lithium smelting slag; where w satisfies 0.5% ≤ w < 35%;

[0016] When the calcium content in the industrial solid waste is less than 60%, the weight of the solidification and stabilization agent is k times the weight of the lithium smelting slag; k satisfies 35% ≤ k < 500%.

[0017] By adopting the above technical solution, the weight of the solidification and stabilization agent in this application is negatively correlated with the calcium content in the industrial solid waste. When the calcium content in the industrial solid waste is not less than 60%, the dosage of the solidification and stabilization agent is 0.5%-35% of the lithium smelting slag; when the calcium content is less than 60%, the dosage is 35%-500% of the lithium smelting slag. This measure not only significantly improves the solidification effect of beryllium in lithium smelting slag, ensuring that the leaching concentration of beryllium in the treated lithium smelting slag meets the requirements of the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB 5085.3-2007), but also significantly reduces treatment costs and improves economic efficiency by optimizing the dosage of the agent. At the same time, using industrial solid waste as the agent not only provides a wide range of raw material sources and low costs, but also reduces secondary pollution, promotes resource recycling, and conforms to the concept of sustainable development. The entire treatment process is simple and easy to implement, facilitating large-scale promotion and application, and is of great significance for the harmless disposal and resource utilization of highly toxic lithium slag.

[0018] Preferably, the calcium-containing compound includes calcium sulfate and calcium hydroxide.

[0019] By adopting the above-mentioned technical solution, the calcium-containing compounds in this application include calcium sulfate and calcium hydroxide, which significantly improves the solidification effect of beryllium in lithium smelting slag. Calcium sulfate and calcium hydroxide, through lattice substitution and adsorption, can efficiently fix beryllium in lithium smelting slag, reduce its leaching risk, and ensure that the leaching concentration of beryllium in the treated lithium smelting slag meets the requirements of the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB 5085.3—2007). These two calcium-containing compounds are widely available and inexpensive; through reasonable selection and proportioning, treatment costs can be significantly reduced, and economic benefits improved. At the same time, this solution has strong adaptability and can achieve good solidification effects under different calcium contents. Furthermore, using calcium sulfate and calcium hydroxide from industrial solid waste as reagents not only reduces secondary pollution but also promotes resource recycling, which is in line with the concept of sustainable development. The entire treatment process is simple and easy to implement, facilitating large-scale application and is of great significance for the harmless disposal and resource utilization of highly toxic lithium slag.

[0020] Optionally, the weight ratio of calcium sulfate to calcium hydroxide is 1:(0.05-1).

[0021] Optionally, the calcium-containing compound includes calcium sulfate, calcium hydroxide, and calcium phosphate.

[0022] By adopting the above technical solution, the calcium-containing compounds in this application include calcium sulfate, calcium hydroxide, and calcium phosphate. This measure significantly improves the solidification effect of beryllium in lithium smelting slag. Calcium sulfate, calcium hydroxide, and calcium phosphate can efficiently fix beryllium in lithium smelting slag through lattice substitution and adsorption, reducing its leaching risk and ensuring that the leaching concentration of beryllium in the treated lithium smelting slag meets the requirements of the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB 5085.3—2007). These three calcium-containing compounds are widely available and inexpensive. Through reasonable selection and proportioning, treatment costs can be significantly reduced and economic benefits improved. At the same time, this solution has strong adaptability and can achieve good solidification effects under different calcium contents. When the calcium content in industrial solid waste is not less than 60%, the dosage of solidification and stabilization agent is 0.5%-35% of the lithium smelting slag; when the calcium content is less than 60%, the dosage of agent is 35%-500% of the lithium smelting slag. Furthermore, using calcium sulfate, calcium hydroxide, and calcium phosphate from industrial solid waste as reagents not only reduces secondary pollution but also promotes resource recycling, aligning with the concept of sustainable development. The entire treatment process is simple and easy to implement, facilitating large-scale application and holding significant importance for the harmless disposal and resource utilization of highly toxic lithium slag.

[0023] Optionally, the weight ratio of calcium sulfate, calcium hydroxide, and calcium phosphate is 1:(0.05-1):(0.01-0.3).

[0024] Optionally, the calcium-containing compound includes calcium sulfate, calcium hydroxide, calcium phosphate, and calcium carbonate.

[0025] By adopting the above-mentioned technical solution, the calcium-containing compounds in this application include calcium sulfate, calcium hydroxide, calcium phosphate, and calcium carbonate. This measure significantly improves the solidification effect of beryllium in lithium smelting slag. These calcium-containing compounds work together through multiple mechanisms to more comprehensively and effectively fix beryllium in lithium smelting slag, reduce its leaching risk, and ensure that the leaching concentration of beryllium in the treated lithium smelting slag meets the requirements of the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB 5085.3—2007). These four calcium-containing compounds are widely available and inexpensive. Through reasonable selection and proportioning, treatment costs can be significantly reduced and economic benefits improved. This solution has strong adaptability and can achieve good solidification effects under different calcium contents. When the calcium content in industrial solid waste is not less than 60%, the dosage of solidification and stabilization agent is 0.5%-35% of the lithium smelting slag; when the calcium content is less than 60%, the dosage of agent is 35%-500% of the lithium smelting slag. Furthermore, using these calcium-containing compounds from industrial solid waste as reagents not only reduces secondary pollution but also promotes resource recycling, aligning with the concept of sustainable development. The entire treatment process is simple and easy to implement, facilitating large-scale application and holding significant importance for the harmless disposal and resource utilization of highly toxic lithium slag.

[0026] Optionally, the weight ratio of calcium sulfate, calcium hydroxide, calcium phosphate and calcium carbonate is 1:(0.05-1):(0.01-0.3):(0.005-0.2).

[0027] Optionally, the ball milling speed in step S2 is 100-2000 rpm; the ball milling time is 0.5-4 h.

[0028] In summary, the present invention includes at least one of the following beneficial technical effects.

[0029] 1. This application provides a method for inhibiting beryllium leaching from lithium smelting slag, which solves the problem of beryllium leaching from lithium smelting slag. The calcium-containing compound in this application can effectively fix beryllium in lithium smelting slag through lattice substitution and adsorption, reducing its leaching risk; in addition, the entire treatment process is simple and easy to implement, facilitating large-scale application. In summary, this application provides a highly efficient and easy-to-operate method for inhibiting beryllium leaching from lithium smelting slag, which is of great significance for the harmless disposal of highly toxic lithium slag.

[0030] 2. The solidification and stabilizing agent in this application is derived from industrial solid waste. This measure not only effectively solves the leaching problem of beryllium in lithium smelting slag but also realizes the resource utilization of industrial solid waste, achieving both environmental and economic benefits. Using industrial solid waste as the agent not only provides a wide range of raw materials at low cost but also reduces secondary pollution and promotes resource recycling. This makes the entire treatment process more economical and feasible, and also aligns with the concept of sustainable development. In summary, this technical solution significantly improves the efficiency and environmental performance of lithium smelting slag treatment, and is of great significance for the harmless disposal and resource utilization of highly toxic lithium slag.

[0031] 3. The calcium-containing compounds in this application include calcium sulfate, calcium hydroxide, calcium phosphate, and calcium carbonate. This measure significantly improves the solidification effect of beryllium in lithium smelting slag. These calcium-containing compounds work together through multiple mechanisms to more comprehensively and effectively fix beryllium in lithium smelting slag, reduce its leaching risk, and ensure that the leaching concentration of beryllium in the treated lithium smelting slag meets the requirements of the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB 5085.3—2007). These four calcium-containing compounds are widely available and inexpensive. Through reasonable selection and proportioning, treatment costs can be significantly reduced and economic benefits improved. This scheme has strong adaptability and can achieve good solidification effects under different calcium contents. When the calcium content in industrial solid waste is not less than 60%, the dosage of solidification and stabilization agent is 0.5%-35% of the lithium smelting slag; when the calcium content is less than 60%, the dosage of agent is 35%-500% of the lithium smelting slag. Furthermore, using these calcium-containing compounds from industrial solid waste as reagents not only reduces secondary pollution but also promotes resource recycling, aligning with the concept of sustainable development. The entire treatment process is simple and easy to implement, facilitating large-scale application and holding significant importance for the harmless disposal and resource utilization of highly toxic lithium slag. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0033] The solution of this application will be described below with reference to the following specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available products, and the devices or equipment used are all purchased from conventional market sales channels.

[0034] Lithium smelting slag, especially the waste residue generated after sulfate roasting and leaching of lithium from lepidolite ore, has become a major environmental challenge. With the rapid development of the new energy industry, the demand for lithium carbonate is constantly increasing, resulting in tens of millions of tons of lithium smelting slag produced annually. This waste residue contains toxic heavy metals such as thallium, beryllium, rubidium, and cesium, which can leach and seep through rainwater and other pathways, causing serious pollution to soil and groundwater. Currently, the mainstream treatment approach involves deep removal of these toxic heavy metals through field treatment and mild acid treatment, but beryllium treatment is particularly difficult. Due to its unique properties, beryllium is difficult to completely remove, and even after deep removal treatment, the beryllium that is difficult to leach in lithium smelting slag is actually activated, with leaching concentrations potentially reaching tens or even hundreds of micrograms per liter, far exceeding national standards. This indicates that existing technologies have significant shortcomings in treating beryllium in lithium smelting slag, and there is an urgent need to develop new and effective methods to stabilize and solidify beryllium in lithium smelting slag to reduce its leaching toxicity to levels that meet national standards.

[0035] In view of this, this application provides a method for suppressing beryllium leaching from lithium smelting slag, comprising the following steps:

[0036] S1. The solidification and stabilizing agent is mixed with lithium smelting slag to obtain a mixture.

[0037] S2. Ball mill the mixture from step S1;

[0038] Steps S1 and S2 can be performed directly in the existing lithium smelting process.

[0039] The curing and stabilizing agent in step S1 includes a calcium-containing compound;

[0040] Calcium-containing compounds include at least one of calcium phosphate, calcium sulfate, calcium carbonate, and calcium hydroxide. This invention provides a method for inhibiting beryllium leaching from lithium smelting slag, which solves the problem of beryllium leaching from lithium smelting slag. The calcium-containing compounds in this application can effectively immobilize beryllium in lithium smelting slag through lattice substitution and adsorption, reducing its leaching risk; furthermore, the entire process is simple and easy to implement, facilitating large-scale application. In summary, this application provides an efficient and simple method for inhibiting beryllium leaching from lithium smelting slag, which is of great significance for the harmless disposal of highly toxic lithium slag.

[0041] In some embodiments, the solidification and stabilizing agent is sourced from industrial solid waste. Industrial solid waste includes at least one of waste gypsum, wastewater neutralization slag, carbide slag, desulfurization gypsum slag, and phosphogypsum. The solidification and stabilizing agent in this application is sourced from industrial solid waste. This measure not only effectively solves the problem of beryllium leaching from lithium smelting slag but also realizes the resource utilization of industrial solid waste, achieving both environmental and economic benefits. Using industrial solid waste as the agent not only provides a wide range of raw material sources and low costs but also reduces secondary pollution and promotes resource recycling. This makes the entire treatment process more economical and feasible, and also aligns with the concept of sustainable development. In summary, this technical solution significantly improves the efficiency and environmental performance of lithium smelting slag treatment, and is of great significance for the harmless disposal and resource utilization of highly toxic lithium slag.

[0042] If the calcium-containing compound used in step S1 is a commercially available calcium-containing compound, the weight ratio of the calcium-containing compound to the lithium smelting slag in step S1 is 1:(0.2-200). In some embodiments, the weight ratio of the calcium-containing compound to the lithium smelting slag is 1:0.2, 1:2, 1:20, 1:40, 1:120, 1:150, 1:180, or 1:200. The weight ratio of the calcium-containing compound to the lithium smelting slag in step S1 is related to the type and purity of the calcium-containing compound. If the purity and content of the calcium-containing compound are higher, the solidification effect on beryllium in the lithium smelting slag is better, and the dosage is also lower.

[0043] Optionally, the weight of the solidification and stabilizing agent in step S1 is negatively correlated with the content of calcium-containing compounds in the solid waste;

[0044] When the calcium content in industrial solid waste is not less than 60%, the weight of the solidification and stabilization agent is w of the weight of lithium smelting slag; w satisfies 0.5% ≤ w < 35%.

[0045] When the calcium content in industrial solid waste is less than 60%, the weight of the solidification and stabilization agent is k times the weight of the lithium smelting slag; k satisfies 35% ≤ k < 500%.

[0046] In some embodiments, the calcium content in the industrial solid waste is a value within the range of 60%, 65%, 70%, 80%, 85%, 90%, 95%, 98%, or any two of these.

[0047] In some embodiments, the weight of the solidification stabilizing agent is a value within the range of 0.5%, 5%, 10%, 15%, 20%, less than 35%, or any two of the weight of the lithium smelting slag.

[0048] In some embodiments, the calcium content in industrial solid waste is a value within the range of less than 60%, 45%, 30%, 25%, 20%, 10%, 5%, 3%, or any two of these.

[0049] In some embodiments, the weight of the solidification stabilizing agent is a value within the range of 35%, 50%, 65%, 75%, 90%, 100%, 200%, 300%, 400%, 500% or any two of the weight of the lithium smelting slag.

[0050] Optional, calcium-containing compounds include calcium sulfate and calcium hydroxide.

[0051] Optionally, the weight ratio of calcium sulfate to calcium hydroxide is 1:(0.05-1).

[0052] In some embodiments, the weight ratio of calcium sulfate to calcium hydroxide is a value within the range of 1:0.05, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, or any two of these ratios.

[0053] In some embodiments, the calcium-containing compound includes calcium sulfate, calcium hydroxide, and calcium phosphate.

[0054] Optionally, the weight ratio of calcium sulfate, calcium hydroxide and calcium phosphate is 1:(0.05-1):(0.01-0.3).

[0055] Optionally, the weight ratio of calcium sulfate, calcium hydroxide, and calcium phosphate is 1:0.05:0.01, 1:1:0.2, 1:1:0.3, or any combination thereof.

[0056] In some embodiments, the calcium-containing compound includes calcium sulfate, calcium hydroxide, calcium phosphate, and calcium carbonate.

[0057] Optionally, the weight ratio of calcium sulfate, calcium hydroxide, calcium phosphate and calcium carbonate is 1:(0.05-1):(0.01-0.3):(0.005-0.2).

[0058] In some embodiments, the weight ratio of calcium sulfate, calcium hydroxide, calcium phosphate, and calcium carbonate is:

[0059] The value is within the range of 1:0.05:0.01:0.005, 1:0.8:0.2:0.1, 1:1:0.3:0.2, or any two of these.

[0060] Optionally, in step S2, the ball milling speed is 100-2000 rpm; the ball milling time is 0.5-4 h.

[0061] In some embodiments, the ball milling speed in step S2 is a value within the range of 100 rpm, 500 rpm, 1000 rpm, 1500 rpm, 2000 rpm, or any two of these; the ball milling time is a value within the range of 0.5 h, 2 h, 3 h, 4 h, or any two of these.

[0062] Example 1

[0063] This embodiment provides a method for suppressing beryllium leaching from lithium smelting slag, comprising the following steps:

[0064] S1. Weigh two portions of lithium smelting slag samples A and C after deep detoxification, 10g each, and put them into 250ml conical flasks, and record them as lithium smelting slag samples A1, A2 and C1, C2.

[0065] S2. Take the lithium smelting slag samples A2 and C2 weighed in step S1 and put them into 50ml centrifuge tubes respectively, and then add 2g of solidification and stabilization agent to each tube and mix.

[0066] S3. Add equal portions of zirconia grinding balls (three types of grinding balls: 9 of 4mm, 6 of 6mm, and 3 of 8mm) to the centrifuge tube containing the mixture from step S2.

[0067] S4. Finally, place the centrifuge tube containing the grinding balls from S3 into a ball mill and mill it at 1400 rpm for 1 hour.

[0068] S5. Weigh 10g of each of the ball-milled mixtures A2 and C2 from step S4, and then add them to 250ml conical flasks respectively.

[0069] S6. Leaching experiments were conducted on lithium smelting slag samples A1 and C1 obtained in step S1 and the mixture A2 and C2 after ball milling in step S5, respectively, according to the "Solid Waste Leaching Toxicity Leaching Method - Sulfuric Acid and Nitric Acid Method" (HJT299-2007).

[0070] (4) The concentration of beryllium in the leachate sample was determined by ICP-MS combined with external standard method.

[0071] Analysis and comparison revealed that the beryllium concentrations in the leachates of lithium smelting slag samples A1 and C1 were 342 ug / L and 269 ug / L, respectively, while the beryllium concentrations in the leachates of the mixtures A2 and C2 after reagent treatment and ball milling were 0.52 ug / L and 2.78 ug / L, respectively.

[0072] This indicates that the above-mentioned reagents and methods can effectively inhibit the leaching of beryllium in lithium smelting slag, reducing the beryllium leaching concentration to below 10 ug / L, which meets the requirements of the "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB 5085.3—2007).

[0073] The curing and stabilizing agent in step S2 of this embodiment is calcium sulfate, which was purchased from Shanghai McLean Biochemical Technology Co., Ltd., or CAS No. 7778-18-9.

[0074] Examples 2-4

[0075] The difference between Examples 2-4 and Example 1 is that Examples 2-4 used calcium phosphate, calcium carbonate, and calcium hydroxide as curing and stabilizing agents (all commercially available), respectively, while the steps were consistent with those in Example 1. The sample used in Examples 2-4 was Sample A.

[0076] The CAS number for calcium phosphate is 10103-46-5; the CAS number for calcium carbonate is 471-34-1; and the CAS number for calcium hydroxide is 1305-62-0.

[0077] The experimental test results of Examples 2-4 are shown in Table 1.

[0078] Table 1 - Experimental Detection Results of Examples 2-4

[0079]

[0080] Results Analysis: Combining the experimental results of Examples 1-4 and the control experiment, it is evident that using calcium sulfate, calcium phosphate, calcium carbonate, and calcium hydroxide as solidification and stabilizing agents all resulted in good solidification effects on beryllium in lithium smelting slag. This indicates that these calcium-containing compounds can effectively fix beryllium in lithium smelting slag through multiple mechanisms, reducing its leaching risk and ensuring that the treated lithium smelting slag meets environmental standards. In the control experiment, the leaching concentration of beryllium in the lithium smelting slag without solidification and stabilizing agents reached as high as 342 μg / L, further verifying the effectiveness of the agents. In conclusion, using calcium sulfate, calcium phosphate, calcium carbonate, and calcium hydroxide as solidification and stabilizing agents can significantly improve the solidification effect of beryllium in lithium smelting slag, which is of great significance for the harmless disposal of highly toxic lithium slag.

[0081] Examples 5-8: The sample used in Examples 5-8 is sample A;

[0082] Example 5

[0083] The difference between this embodiment and Embodiment 1 is that the curing and stabilizing agent in step S1 of this embodiment is prepared by mixing calcium sulfate and calcium hydroxide in a weight ratio of 1:0.05, while the rest is the same as in Embodiment 1.

[0084] Example 6

[0085] The difference between this embodiment and Embodiment 1 is that the curing and stabilizing agent in step S1 of this embodiment is prepared by mixing calcium sulfate and calcium hydroxide in a weight ratio of 1:0.8, while the rest is the same as in Embodiment 1.

[0086] Example 7

[0087] The difference between this embodiment and Embodiment 1 is that the curing and stabilizing agent in step S1 of this embodiment is prepared by mixing calcium sulfate and calcium hydroxide in a weight ratio of 1:1, while the rest is the same as in Embodiment 1.

[0088] Example 8

[0089] The difference between this embodiment and embodiment 1 is that the curing and stabilizing agent in step S1 of this embodiment is prepared by mixing calcium phosphate and calcium carbonate in a weight ratio of 1:1, while the rest is the same as in embodiment 1.

[0090] Examples 9-11: The sample used in Examples 9-11 is Sample A;

[0091] Example 9

[0092] The difference between this embodiment and embodiment 7 is that the curing and stabilizing agent in step S2 of this embodiment is prepared by mixing calcium sulfate, calcium hydroxide and calcium phosphate in a weight ratio of 1:0.05:0.01, while the rest is the same as in embodiment 1.

[0093] Example 10

[0094] The difference between this embodiment and embodiment 9 is that the curing and stabilizing agent in step S2 of this embodiment is prepared by mixing calcium sulfate, calcium hydroxide and calcium phosphate in a weight ratio of 1:0.8:0.2, while the rest is the same as in embodiment 1.

[0095] Example 11

[0096] The difference between this embodiment and embodiment 9 is that the curing and stabilizing agent in step S2 of this embodiment is prepared by mixing calcium sulfate, calcium hydroxide and calcium phosphate in a weight ratio of 1:1:0.3, while the rest is the same as in embodiment 1.

[0097] Examples 12-14: The sample used in Examples 12-14 is sample A;

[0098] Example 12

[0099] The difference between this embodiment and embodiment 10 is that the curing and stabilizing agent in step S2 of this embodiment is prepared by mixing calcium sulfate, calcium hydroxide, calcium phosphate and calcium carbonate in a weight ratio of 1:0.05:0.01:0.005, while the rest is the same as in embodiment 1.

[0100] Example 13

[0101] The difference between this embodiment and embodiment 12 is that the curing and stabilizing agent in step S2 of this embodiment is prepared by mixing calcium sulfate, calcium hydroxide, calcium phosphate and calcium carbonate in a weight ratio of 1:0.8:0.2:0.1, while the rest is the same as in embodiment 1.

[0102] Example 14

[0103] The difference between this embodiment and embodiment 12 is that the curing and stabilizing agent in step S2 of this embodiment is prepared by mixing calcium sulfate, calcium hydroxide, calcium phosphate and calcium carbonate in a weight ratio of 1:1:0.3:0.2, while the rest is the same as in embodiment 1.

[0104] The experimental test results of Examples 5-14 and Example 1 are shown in Table 2.

[0105] Table 2 - Experimental Detection Results of Examples 5-14 and Example 1

[0106]

[0107] Results Analysis: Based on the experimental results in Table 2, compared with Example 1, the leaching concentration of beryllium in lithium smelting slag was significantly reduced after using different types and ratios of solidification and stabilizing agents in Examples 5-14, especially when used in combination. Specifically, in Examples 5-8, only calcium sulfate and calcium hydroxide were used as solidification and stabilizing agents, showing a certain solidification effect. However, the effect was more prominent when multiple calcium-containing compounds were used in combination. In Examples 9-11, the leaching concentration was further reduced to 0.20 μg / L using a compound agent of calcium sulfate, calcium hydroxide, and calcium phosphate, which was significantly better than the single-component agent. In Examples 12-14, calcium carbonate was further added to form a four-component compound agent of calcium sulfate, calcium hydroxide, calcium phosphate, and calcium carbonate, and the leaching concentration was reduced to a minimum of 0.10 μg / L, far below the requirement of 20 μg / L in the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB5085.3—2007). These results indicate that the rational combination of calcium sulfate, calcium hydroxide, calcium phosphate, and calcium carbonate can significantly improve the solidification effect of beryllium in lithium smelting slag, effectively prevent its leaching, and is of great significance for the harmless treatment of highly toxic lithium slag.

[0108] Examples 15-16: The samples used in Examples 15-16 were industrial solid waste.

[0109] Example 15

[0110] The difference between this embodiment and Embodiment 1 is that the solidification and stabilizing agent in step S2 of this embodiment is sourced from industrial solid waste, specifically waste gypsum. In this embodiment, the waste gypsum contains 85% calcium compounds, with the remainder being impurities. The calcium compound in this embodiment is calcium sulfate (calcium sulfate accounts for 99% of the total weight of the calcium compound).

[0111] In this embodiment, the amount of industrial solid waste used at one time is 3g, and the amount of lithium smelting slag used at one time is 10g.

[0112] This embodiment uses a lithium smelting slag sample from a deeply de-removed lithium smelting plant in Yichun City (same as in Example 1). This embodiment uses a 250ml conical flask as the reaction vessel and specifically includes the following steps:

[0113] S1. Weigh two portions of lithium smelting slag samples A and C after deep detoxification, 10g each, and put them into 250ml conical flasks, and record them as lithium smelting slag samples A1, A2 and C1, C2.

[0114] S2. Take the lithium smelting slag samples A2 and C2 weighed in step S1 and put them into 50ml centrifuge tubes respectively, and then add 3g of solidification and stabilization agent to each tube and mix.

[0115] S3. Add equal portions of zirconia grinding balls (three types of grinding balls: 9 of 4mm, 6 of 6mm, and 3 of 8mm) to the centrifuge tube containing the mixture from step S2.

[0116] S4. Place the centrifuge tube loaded with grinding balls in step S3 into a ball mill and mill at 2000 rpm for 0.8 hours.

[0117] S5. Weigh 10g of each of the ball-milled mixtures A2 and C2 from step S4, and then add them to 250ml conical flasks respectively.

[0118] S6. Leaching experiments were conducted on lithium smelting slag samples A1 and C1 obtained in step S5 and ball-milled mixtures A2 and C2, respectively, according to the "Solid Waste Leaching Toxicity Leaching Method - Sulfuric Acid and Nitric Acid Method" (HJT299-2007).

[0119] S7. The concentration of beryllium in the leachate sample was determined by ICP-MS combined with external standard method.

[0120] Analysis and comparison revealed that the beryllium concentrations in the leachates of lithium smelting slag samples A1 and C1 were 342 ug / L and 269 ug / L, respectively, while the beryllium concentrations in the leachates of the mixtures A2 and C2 after reagent treatment and ball milling were 0.46 ug / L and 2.33 ug / L, respectively. This indicates that the aforementioned reagents and methods can effectively inhibit the leaching of beryllium from lithium smelting slag, reducing the beryllium leaching concentration to below 10 ug / L, which meets the requirements of the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB 5085.3—2007).

[0121] Example 16

[0122] The difference between this embodiment and Embodiment 15 is that the solidification and stabilizing agent in step S2 of this embodiment is sourced from industrial solid waste, specifically desulfurized gypsum slag. The desulfurized gypsum slag contains approximately 90% calcium compounds, with the remainder being impurities. In this embodiment, the ball mill speed is 1800 rpm, and the milling time is 1.5 hours.

[0123] The calcium-containing compound in this embodiment includes calcium sulfate and calcium carbonate in a weight ratio of 1:0.2. The total amount of calcium sulfate and calcium carbonate accounts for approximately 99% of the total weight of the calcium-containing compound. In this embodiment, the single usage amount of industrial solid waste is 2.5g, and the single usage amount of lithium smelting slag is 10g.

[0124] The experimental test results of Examples 15-16 are shown in Table 3.

[0125] Table 3 - Experimental Detection Results of Examples 15-16

[0126]

[0127] Results Analysis: The difference between Examples 15-16 and Example 1 is that industrial solid waste was used in Examples 15-16 instead of commercially available calcium sulfate in Example 1. Combined with the experimental data provided in Table 3, it can be seen that the use of industrial solid waste reduced the beryllium leaching concentration to below 10 μg / L, meeting the requirements of the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB 5085.3-2007). Therefore, industrial solid waste not only effectively solved the beryllium leaching problem in lithium smelting slag but also achieved resource utilization of industrial solid waste, achieving both environmental and economic benefits. Using industrial solid waste as a reagent not only provides a wide range of raw material sources and low costs but also reduces secondary pollution and promotes resource recycling. This makes the entire treatment process more economical and feasible, and also aligns with the concept of sustainable development. In summary, the technical solution provided in this application significantly improves the efficiency and environmental performance of lithium smelting slag treatment, and is of great significance for the harmless disposal and resource utilization of highly toxic lithium slag.

[0128] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the principles of this application should be included within the protection scope of this application.

Claims

1. A method for suppressing beryllium leaching from lithium smelting slag, characterized in that, The method includes the following steps: S1. The solidification and stabilizing agent is mixed with lithium smelting slag to obtain a mixture. S2. The mixture described in step S1 is ball-milled; The curing and stabilizing agent mentioned in step S1 includes a calcium-containing compound; The calcium-containing compounds include calcium sulfate, calcium hydroxide, calcium phosphate, and calcium carbonate; The weight ratio of calcium sulfate, calcium hydroxide, calcium phosphate, and calcium carbonate is 1:(0.05-1):(0.01-0.3):(0.005-0.2). The solidification and stabilizing agent is derived from industrial solid waste; the industrial solid waste includes at least one of waste gypsum, wastewater neutralization slag, carbide slag, desulfurization gypsum slag, and phosphogypsum.

2. The method according to claim 1, characterized in that, The weight of the solidification and stabilization agent in step S1 is negatively correlated with the content of calcium-containing compounds in the solid waste; When the calcium compound content in the industrial solid waste is not less than 60%, the weight of the solidification and stabilization agent is w of the weight of the lithium smelting slag; where w satisfies 0.5% ≤ w < 35%; When the calcium compound content in the industrial solid waste is less than 60%, the weight of the solidification and stabilization agent is k times the weight of the lithium smelting slag; k satisfies 35% ≤ k < 500%.

3. The method according to claim 1, characterized in that, The ball milling speed in step S2 is 100-2000 rpm; the ball milling time is 0.5-4 h.

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