Method for extracting lithium compound from lithium-containing solid waste
By using hybrid solution of methalic acid and alcohol, ether, and ester substances as lithium extract, the problem of high energy consumption, environmental pollution and high cost in the existing technologies can be solved. The effect of lithium extraction and cycling uses solvents.
Patent Information
- Application Number
- CN202411445805.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2025-01-28
AI Technical Summary
In the prior art, when extracting lithium compounds from lithium-containing solid waste, there are problems of high energy consumption, environmental pollution and high costs, and it is difficult to effectively recover lithium resources.
The mixture of methalic acid and alcohol, ether, and ester substances is used as a lithium extract, and solid solid solids and distillations are performed by stirring with lithium solid waste. To reduce solvent consumption.
The efficient and highly selective lithium extraction, lithium extraction rate and product purity are high, the process is produced without three wastes, solvents can be used multiple times, which significantly reduces environmental pollution and production costs.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of recycling and treating lithium-containing solid waste, and in particular relates to a method for extracting lithium compounds from lithium-containing solid waste. Background Art
[0002] The current social demand for lithium resources continues to grow, mainly due to the popularity of electric vehicles, mobile electronic devices and renewable energy storage. The demand for electric vehicle power batteries, the popularity of mobile devices, and the development of renewable energy storage technology and equipment, among which the main energy storage components are lithium-containing battery materials based on ternary lithium batteries or lithium iron phosphate batteries, especially the strong demand for lithium battery electric vehicles and energy storage, have dramatically driven the industry's demand for lithium resources. This growing trend in demand has also prompted people to pay more attention to the mining, production and recycling of lithium resources.
[0003] The main sources of lithium resources include lithium ore and lithium salt lakes. At present, the industrial methods for extracting lithium ore include hard rock ore extraction, salt lake evaporation, underground salt water extraction and smelting extraction. Hard rock ore extraction is one of the common methods, involving complex processes such as mining, crushing, grinding and flotation. Through these steps, the target minerals are separated from the ore, and then lithium compounds are obtained through hydrometallurgical processes. The salt lake evaporation method is aimed at salt lake water bodies rich in lithium ions, using solar energy to gradually evaporate water to obtain industrial salt, while lithium ions are further concentrated, and then lithium salt compounds are obtained through separation and purification. Similar to this is the underground salt water extraction method, which extracts salt water rich in target minerals from underground salt water, and then extracts it through chemical treatment or electrolysis. For the case of metal sulfide ores, smelting extraction is a common technology that extracts metals from sulfide ores through high-temperature smelting. In addition, heap leaching is a treatment method for low-grade ores. The ore is piled in a heap leaching field and immersed in an extractant solution to dissolve the target mineral, followed by precipitation or electrolysis and other process steps. Although hard rock ore extraction can effectively utilize the lithium mineral resources in hard rock mines, it consumes a lot of energy and water resources and may cause damage to the environment. The disposal of tailings is also a major problem and pain point. The salt lake evaporation method is only relatively rich in salt lake areas such as Qinghai Lake, but the long-term evaporation process and the impact on the local ecological environment are its disadvantages. The underground salt water extraction method can reduce the exploitation of surface resources, but it relies on groundwater resources and also has consumption and pollution risks.
[0004] In addition to extracting lithium resources from traditional lithium ores or salt lakes, there are many other lithium-containing solid wastes that are also important lithium resources. Lithium compounds can also be efficiently extracted by appropriate methods. For example, lithium-containing positive electrode materials, lithium battery recycling mixed black powder, lithium-rich aluminum electrolyte slag, microcrystalline glass slag, lithium mica slag, lithium-containing raw ore powder, etc., waste lithium battery positive electrode materials or black powder after disassembly of waste lithium batteries, mostly use hydrometallurgical or pyrometallurgical methods to extract lithium or other precious metal compounds, consume a large amount of acid and alkali agents and extractants, etc., and have been widely studied and applied. It is currently the mainstream process route for recycling and extracting lithium from waste lithium batteries. Waste slag from the electrolytic aluminum industry is also a potential lithium resource. Due to the relatively low lithium content in the waste slag, it is difficult to effectively extract and recycle, so the treatment of waste slag has always been a problem. At present, the most commonly used way to extract lithium from electrolytic aluminum waste slag is to use lithium-containing electrolytic aluminum waste slag and concentrated sulfuric acid as raw materials, and then carry out leaching, alkaline hydrolysis, causticization, carbonization and other processes to prepare battery-grade lithium carbonate. The characteristics of this process are: the obtained battery-grade lithium carbonate has a low content of impurity ions, which solves the current problems of low yield, high production cost and weak market competitiveness in the preparation of battery-grade lithium carbonate from ore. However, the recovery process using strong acid such as concentrated sulfuric acid as raw material not only requires the reaction vessel of the recovery process to be resistant to strong acid and corrosion, but also produces a large amount of acid-containing wastewater, which is harmful to the environment and increases the recovery cost. It can be seen that the currently commonly used mineral extraction methods are not only harmful to the environment, but also have greatly reduced economic benefits.
[0005] In summary, for lithium-containing solid waste, it is urgent to develop new, green, efficient and low-cost lithium extraction methods. Summary of the invention
[0006] The purpose of the present invention is to solve the above technical problems and propose a method for extracting lithium compounds from lithium-containing solid waste. The method can achieve efficient and highly selective extraction of lithium compounds from a variety of different lithium-containing solid wastes, with high lithium extraction rate and lithium product purity, and the solvent can be recycled for multiple times. The whole process does not produce three wastes, and has important environmental and economic benefits.
[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:
[0008] A method for extracting lithium compounds from lithium-containing solid waste is provided, comprising the following steps:
[0009] The lithium-containing solid waste and the lithium extract are fully stirred, and after the stirring is completed, a lithium-containing clear liquid is obtained by solid-liquid separation, and the lithium-containing clear liquid is distilled and dried to obtain a lithium compound, and the condensate obtained by distillation is collected and recycled as a lithium extract; wherein:
[0010] The lithium extraction solution is a mixture of formic acid (HCOOH) and a promoter, and the promoter is at least one of alcohols, ethers, and esters.
[0011] According to the above scheme, the mass percentage concentration of the promoter in the lithium extraction solution is 5-50%.
[0012] According to the above scheme, the condensate obtained by distillation is collected and recycled 1 to 10 times.
[0013] According to the above scheme, when the condensate is recycled as a lithium extraction solution, the insufficient amount is supplemented by adding fresh lithium extraction solution.
[0014] According to the above scheme, the total carbon number of the alcohol substance is C1-C6; the total carbon number of the ether substance is C1-C6; the total carbon number of the ester substance is C1-C6.
[0015] According to the above scheme, the lithium-containing solid waste is at least one of lithium battery recycled mixed black powder, lithium-rich aluminum electrolyte slag, microcrystalline glass slag, lithium mica slag, and lithium-containing raw ore powder.
[0016] According to the above scheme, the lithium mass proportion of the lithium-containing solid waste is 0.1-10%.
[0017] According to the above scheme, the mass ratio of the lithium-containing solid waste to the lithium extract is 0.005-0.05:1.
[0018] According to the above scheme, the stirring temperature is 60-100°C, and the stirring time is 8-12h; preferably, the stirring speed is 100-1000rpm.
[0019] According to the above scheme, the drying operation is carried out in an air atmosphere, the drying temperature is 90-120° C., and the drying time is 3-5 hours.
[0020] According to the above scheme, the lithium-containing clear liquid obtained by solid-liquid separation of the reaction liquid after the reaction can be recycled for multiple times to obtain the condensate obtained by distillation.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] The present invention provides a method for extracting lithium compounds from lithium-containing solid wastes. The method can realize the extraction of lithium compounds from a variety of different lithium-containing solid wastes by simply stirring the lithium-containing solid wastes with a lithium extracting solution. The method has high selectivity, high lithium extraction rate and high purity of lithium products. No additional impurities are introduced in the process, and separation and purification are simple. Meanwhile, the solvent can be recycled and reused multiple times, which hardly affects the extraction effect of lithium. No three wastes are generated in the whole process, and the consumption of the solvent is significantly reduced, thereby having important environmental protection and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1The actual process diagram of Example 1 is shown, including a diagram of the system after stirring (a) and a diagram of the system after drying (b). DETAILED DESCRIPTION
[0024] In order to enable those skilled in the art to fully understand the technical solutions and beneficial effects of the present invention, the following is further described in conjunction with the accompanying drawings and specific implementation schemes. In order to further illustrate the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and examples, but they should not be understood as limiting the scope of protection of the present invention.
[0025] Example 1
[0026] Provided is a method for extracting lithium compounds from lithium-rich aluminum electrolyte slag, wherein the lithium-rich aluminum electrolytic slag contains 1.3% lithium, 27.5% aluminum, and the rest are impurities such as Fe, Na, Ca, and Mg;
[0027] The method comprises the following steps:
[0028] A mixture of formic acid and ethyl formate is used as a lithium extract, and the mass percentage concentration of ethyl formate in the lithium extract is 15%; lithium-rich aluminum electrolyte slag powder is added to the lithium extract, and the mass ratio of lithium-rich aluminum electrolyte slag powder to lithium extract is 0.02:1, and stirring is carried out at 60°C for 12 hours under a stirring speed of 480rpm. Subsequently, a clear liquid with a high lithium content is obtained by centrifugation. After distillation, the clear liquid is dried at 120°C in an air atmosphere for 3 hours to obtain a lithium-containing solid product with high purity. The distillate is recovered by condensation and can be reused as a lithium extract.
[0029] The physical appearance of the system after stirring and after drying is as follows: Figure 1 shown.
[0030] The extraction results of repeated experiments are shown in Table 1.
[0031] Example 2
[0032] Provided is a method for extracting lithium compounds from mixed black powder recycled from lithium batteries. The recycled black powder from lithium batteries contains: Li 2.8%, Fe 31.4%, P 18.2%, and other impurities such as C, Cu, and Al.
[0033] The method comprises the following steps:
[0034] A mixture of formic acid and cyclopropanol is used as a lithium extract, and the mass percentage concentration of cyclopropanol in the lithium extract is 10%; lithium battery recovery black powder is added to the lithium extract, and the mass ratio of lithium battery recovery black powder to lithium extract is 0.03:1, and the reaction is stirred at 70°C with condensation reflux for 10 hours, and the stirring speed is 560rpm. After the reaction is completed, a clear liquid with a high lithium content is obtained by centrifugation. The liquid is distilled to obtain a gray solid powder, and the powder is dried at 110°C in an air atmosphere for 4 hours to obtain a lithium-containing solid product with high purity. The distillate is recovered by condensation.
[0035] The condensate collected by distillation and condensation in this embodiment is recovered and recycled as a lithium extraction solution. The insufficient part is supplemented by adding fresh lithium extraction solution. The above lithium extraction process is repeated to obtain a lithium-containing solid product and a recovered condensate. The above experiment is repeated many times to obtain the results in Table 2.
[0036] Example test method:
[0037] About 0.05 g of lithium-containing solid product was digested with 10 mL of concentrated nitric acid, diluted to 1000 mL (so that the nitric acid content was less than 2%), and inductively coupled plasma mass spectrometry (ICP) and atomic absorption spectroscopy (AAS) were measured to obtain the content of lithium and other elements in the product, and the lithium extraction rate and product purity were calculated.
[0038] The test results are as follows,
[0039] Table 1. Lithium extraction effect of lithium-rich aluminum electrolyte slag in Example 1
[0040] Parallel repeat test Lithium extraction rate Lithium product purity 1 94.20％ 55.47％ 2 93.71％ 60.28％ 3 93.43％ 57.09％
[0041] Table 2. Lithium extraction effect of multiple cycles of lithium extraction solution in Example 2
[0042]
[0043]
[0044] Results Analysis
[0045] From the analysis of the examples and their results, it can be seen that the mixed solvent mainly composed of formic acid as a lithium extraction solution has a good effect of extracting lithium from a variety of lithium-containing solid wastes, and the mixed solvent has good recyclability and has excellent application prospects.
[0046] It is necessary to point out that the above embodiments are limited to further elaboration and explanation of the technical solution of the present invention, and are not further limitations of the technical solution of the present invention. The method of the present invention is only a part of the implementation scheme, and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for extracting lithium compounds from lithium-containing solid waste, characterized in that: The following steps are involved: The lithium-containing solid waste and the lithium extract are fully stirred, and after the stirring is completed, a lithium-containing clear liquid is obtained by solid-liquid separation, and the lithium-containing clear liquid is distilled and dried to obtain a lithium compound, and the condensate obtained by distillation is collected and recycled as a lithium extract; wherein: The lithium extraction solution is a mixture of formic acid and a promoter, and the promoter is at least one of alcohols, ethers and esters.
2. The method according to claim 1, characterized in that: In the lithium extraction solution, the mass percentage concentration of the promoter is 5-50%.
3. The method according to claim 1, characterized in that The condensate obtained by distillation is collected and recycled for 1 to 10 times.
4. The method according to claim 1, characterized in that The total carbon number of the alcohol, ether or ester substance is C1-C6.
5. The method according to claim 1, characterized in that: The lithium-containing solid waste is at least one of lithium battery recycled mixed black powder, lithium-rich aluminum electrolyte slag, microcrystalline glass slag, lithium mica slag, and lithium-containing raw ore powder.
6. The method according to claim 1, characterized in that The lithium mass proportion of the lithium-containing solid waste is 0.1-10%.
7. The method according to claim 1, characterized in that The mass ratio of the lithium-containing solid waste to the lithium extraction solution is 0.005-0.05:
1.
8. The method according to claim 1, characterized in that: The stirring temperature is 60-100° C., and the stirring time is 8-12 h.
9. The method according to claim 8, characterized in that The stirring speed is 100-1000rpm.
10. The method according to claim 1, characterized in that The drying operation is carried out in an air atmosphere, the drying temperature is 90-120° C., and the drying time is 3-5 hours.