Method for co-processing lithium-containing waste material with fluorine-containing material

Abstract

The present application relates to resource recycling and environmental protection, and discloses a method for collaborative treatment of lithium-containing waste and fluorine-containing material, comprising the following steps: putting lithium-containing waste, fluorine-containing material, chlorine-containing material and calcium-containing material into a reactor to react, to obtain a first reaction product; leaching the first reaction product to obtain a second reaction product; and performing solid-liquid separation on the second reaction product to obtain a lithium-containing solution and leaching residue. The method creatively proposes a method for collaborative treatment of lithium-containing waste, fluorine-containing organic waste and chlorine-containing organic waste, and by adding calcium-containing material in the thermal reduction process, not only is the efficient recovery of lithium in lithium-containing waste achieved, but also the environmental pollution problem caused by chlorine and fluorine in fluorine-containing organic waste and chlorine-containing organic waste is solved, and the chlorine is converted into LiCl product form for recovery, and the fluorine is fixed in the form of CaF2.

Description

Technical Field

[0001] This invention relates to the field of resource recycling and environmental protection technology, and in particular to a method for the co-processing of lithium-containing waste and fluorine-containing materials. Background Technology

[0002] Lithium-ion batteries are widely used due to their excellent cycle performance and high energy density, especially in the field of new energy vehicles, where they have experienced rapid development and a year-on-year increase in installed capacity. However, due to their limited lifespan (typically 3-5 years), a large number of lithium-ion batteries will become obsolete. These obsolete lithium-ion batteries contain a significant amount of valuable metals, giving them high recycling value. However, their composition also includes a large number of environmentally harmful substances, such as organic compounds like binders, separators, and electrolytes. Therefore, how to safely and effectively recycle used lithium-ion batteries has become a major challenge.

[0003] Currently, there are two main methods for recycling waste lithium-ion batteries: pyrometallurgical recycling and hydrometallurgical recycling. Pyrometallurgical recycling has high energy consumption, low product purity, and significant environmental pollution. In contrast, hydrometallurgical recycling has the advantages of being environmentally friendly and having high recycling efficiency, and its application prospects are very broad. Among the many hydrometallurgical recycling processes for waste lithium-ion batteries, thermal reduction-water immersion is considered the most promising method. This process can make full use of the battery's own organic matter (binder, electrolyte, separator) as a reducing agent, which can convert waste lithium-ion batteries into soluble lithium salts and convert high-valence oxides of nickel / manganese / cobalt into low-valence oxides or metal forms that are insoluble in water, thereby achieving selective extraction of lithium. The advantages of this process are: (1) it makes full use of the reducing substances contained in the battery itself, without the need for external fuel or reducing agent; (2) this process only requires simple water immersion to effectively recover lithium from the thermal reduction products. This method is more environmentally friendly and has a lower cost than acid immersion. However, this method also has significant limitations. For example, polyvinylidene fluoride (PVDF), a commonly used binder in lithium-ion battery materials, will produce water-insoluble LiF if used as a reducing agent in the thermal reduction process, affecting the subsequent leaching efficiency and significantly reducing the Li recovery rate. On the other hand, this process also generates a large amount of fluorine-containing harmful gases such as HF, PF5, and POF3, which cause serious environmental pollution.

[0004] To address the aforementioned issues, Chinese invention patent CN111495925A, entitled "A Method for Pyrolysis and Defluorination of Waste Lithium Batteries," describes a process involving two rounds of crushing and sorting followed by pyrolysis in a closed rotary kiln to remove fluorine and chlorine, with the fluorine and chlorine being absorbed in situ using a harmful gas absorbent. The exhaust gas is then treated through condensation, dust removal, spraying, adsorption, and combustion. However, this process is cumbersome, and the fluorine and chlorine are not converted into product substances for recycling.

[0005] On the other hand, in addition to the fluorine-containing substances in waste lithium-ion batteries themselves, a large amount of fluorine-containing organic waste is generated globally every day, such as waste polytetrafluoroethylene (PTFE), waste perfluoroethylene propylene (FEP), waste meltable polytetrafluoroethylene (PFA), and waste polyvinyl fluoride (PVF) and other fluorine-containing waste plastics. These fluorine-containing organic wastes are mostly recalcitrant organic compounds, and even persistent organic pollutants (such as perfluoroalkyl and polyfluoroalkyl compounds), posing a significant threat to the environment.

[0006] Therefore, there is an urgent need for a method to co-process lithium-containing waste and fluorine-containing materials to solve the above-mentioned technical problems. Summary of the Invention

[0007] The purpose of this invention is to provide a method for the co-processing of lithium-containing waste and fluorine-containing materials, which not only effectively improves the selective leaching rate of lithium, but also solves the problem of safe fluorine emission.

[0008] To achieve the above objectives, the present invention is implemented according to the following technical solution:

[0009] A method for co-processing lithium-containing waste and fluorine-containing materials includes the following steps:

[0010] S1, lithium-containing waste, fluorine-containing materials, chlorine-containing materials and calcium-containing materials are put into the reactor together to react and obtain the first reaction product;

[0011] S2, leach the first reaction product obtained in step S1 to obtain the second reaction product;

[0012] S3, the second reaction product obtained in step S2 is subjected to solid-liquid separation to obtain a lithium-containing solution and leaching residue.

[0013] Preferably, the lithium-containing waste is at least one of the following: waste lithium-ion batteries, lithium-ion batteries with casings that have not been dismantled or crushed, materials containing lithium-ion battery cathode materials after physical sorting (dismantling, crushing, screening, etc.), substandard lithium-ion battery cathode powder or electrode sheets, a mixture of lithium-ion battery waste and nickel-containing materials, a mixture of lithium-ion battery waste and cobalt-containing materials, and a mixture of lithium-ion battery waste and manganese-containing materials.

[0014] Specifically, the lithium-ion battery waste must include at least lithium-ion battery cathode materials.

[0015] Preferably, the lithium-containing waste also contains at least one of cobalt, nickel, manganese, and iron.

[0016] Preferably, among the three raw materials—lithium-containing waste, fluorine-containing materials, and chlorine-containing materials—at least one raw material contains organic matter.

[0017] Further preferred, among the three raw materials—lithium-containing waste, fluorine-containing materials, and chlorine-containing materials—at least one raw material contains organic waste.

[0018] Preferably, the fluorinated material is at least one of fluorinated organic compounds and fluorinated inorganic compounds.

[0019] Preferably, the fluorinated organic matter is fluorinated organic waste. The addition of fluorinated organic waste can provide a reducing agent for thermal reduction (the process in step S1), promoting the reduction and conversion of the positive electrode material in the waste lithium-ion battery.

[0020] Preferably, the fluorine-containing inorganic material is an inorganic material that contains both lithium and fluorine elements.

[0021] Specifically, the addition of inorganic compounds containing both lithium and fluorine can further increase the lithium content in the thermal reduction products, thereby improving the economic efficiency of the process. Examples of inorganic compounds containing both lithium and fluorine include LiF and LiPF6.

[0022] The benefits of adding fluorinated organic waste are as follows: ① The pyrolysis of fluorinated organic matter produces reducing gases and substances, which enhances the reduction of lithium-ion battery cathode materials in lithium-containing waste; ② The co-processing of lithium-containing waste and fluorinated organic waste achieves the co-processing of the two types of waste through one device, without the need for additional hazardous waste treatment production lines.

[0023] Preferably, the chlorine-containing material is at least one of the following: an organic solution containing chlorine, an organic polymer containing chlorine, an organic compound containing chlorine, and an inorganic compound containing chlorine.

[0024] The calcium-containing material is at least one of CaCl2, CaO, CaSO4, Ca(OH)2, Ca(NO3)2, CaCO3, and CaC2.

[0025] Further preferably, the organic solution containing chlorine is an organic waste solution containing chlorine; the organic polymer containing chlorine is an organic waste polymer containing chlorine; and the organic matter containing chlorine is organic waste containing chlorine.

[0026] In this invention, the chlorine-containing materials can be used from pure raw materials (non-waste) commonly used in industry; however, related waste materials can also be used. Using waste materials not only reduces operating costs but also protects the environment, resulting in superior environmental benefits.

[0027] Further preferred, the calcium-containing material is CaCl2. Using CaCl2 provides both chlorine-containing and calcium-containing materials. When using CaCl2 as the calcium-containing material, other chlorine-containing materials are no longer needed. The addition of calcium to the calcium-containing material is to fix the fluorine in the fluorine-containing material, and also to fix the fluorine-containing substances (such as lithium hexafluorophosphate electrolyte and PVDF binder) in the waste lithium-ion batteries themselves.

[0028] Organic polymers containing chlorine can be those that are commonly known or understood, specifically including chlorine-containing plastics, chlorine-containing rubber, and chlorine-containing resins. Waste products containing chlorine-containing organic polymers can also be those that are commonly known or understood, specifically including chlorine-containing plastic waste, chlorine-containing rubber waste, and chlorine-containing resin waste.

[0029] Chlorine-containing materials contain chlorine-containing organic compounds. Using chlorine-containing organic compounds not only makes full use of the chlorine element, but also takes advantage of the reducing properties generated by the pyrolysis of chlorine-containing organic compounds. The reducing properties generated by the pyrolysis of chlorine-containing organic compounds are stronger than the reduction and conversion of transition metal oxides in waste lithium batteries, and can release lithium.

[0030] Preferably, in step S1, the amount of lithium-containing waste, fluorine-containing material, chlorine-containing material, and calcium-containing material added is in a mass ratio of 100:(2-80):(0-80):(1-80); and the reaction temperature of step S1 is 250-1000℃.

[0031] To ensure the reaction effect and improve the lithium leaching rate, the reaction temperature in step S1 is preferably 400-800℃.

[0032] Preferably, in step S2, the leaching agent used in the leaching process is at least one of water and ethanol; the leaching temperature is 15-100℃, and the leaching time is ≥10min.

[0033] More preferably, in step S2, the leaching temperature is 15–85°C and the leaching time is ≥30 min.

[0034] Preferably, in step S3, the lithium-containing solution can be used for the production of lithium compounds;

[0035] If lithium-containing waste contains at least one of nickel, cobalt, or manganese, products containing the corresponding elements can be extracted from the leaching residue.

[0036] Preferably, in step S1, the reactor is at least one of the following: an anaerobic pyrolysis furnace, an aerobic pyrolysis furnace, a rotary kiln, a tunnel kiln, a rotary furnace, and a calcining furnace.

[0037] In step S3, the equipment used for solid-liquid separation is at least one of the following: filter press, centrifuge, plate and frame filter, horizontal disc filter, vertical disc filter, and vacuum filter.

[0038] Organic matter (preferably related organic waste) in fluorine- or chlorine-containing materials can reduce high-valence nickel, cobalt, and manganese in lithium-containing waste to low-valence oxides and metals. Simultaneously, in the presence of calcium-containing materials, lithium in the waste is converted into LiCl, which is soluble in water, ethanol, and mixtures of water and ethanol (alcohol), while fluorine (F) in fluorine-containing materials is fixed as CaF₂. Therefore, after thermal reduction-leaching, lithium can be selectively leached, while fluorine is fixed in the leaching residue. This not only avoids the formation of insoluble LiF and improves the subsequent lithium recovery rate but also solves the environmental pollution problems caused by fluorine-containing materials.

[0039] Beneficial effects:

[0040] (1) The method of the present invention creatively proposes a method for the co-processing of lithium-containing waste, fluorine-containing organic waste and chlorine-containing organic waste. By adding calcium-containing materials during the thermal reduction process, not only is the efficient recovery of lithium in lithium-containing waste achieved, but also the environmental pollution problems caused by chlorine / fluorine in fluorine-containing organic waste and chlorine-containing organic waste, such as the emission of harmful gases such as HF, PF5, and POF3, are solved. Chlorine is converted into LiCl product form for recovery, and fluorine is fixed in the form of CaF2.

[0041] (2) The method of the present invention uses fluorine-containing organic waste and chlorine-containing organic waste as reducing agents in the thermal reduction process, which effectively reduces the consumption of additional energy and achieves the effect of "turning waste into treasure", which greatly alleviates the current environmental crisis.

[0042] (3) The method of the present invention creatively proposes a selective lithium extraction method using alcohol (a mixture of water and ethanol). Since the boiling point of alcohol is significantly lower than that of water and its heat capacity is also significantly lower than that of water, the lithium-containing solution can be recovered by evaporation and crystallization, and the energy consumption for lithium extraction is significantly reduced. Detailed Implementation

[0043] The present invention will be further described below with reference to specific embodiments. The illustrative embodiments and descriptions herein are used to explain the present invention, but are not intended to limit the present invention.

[0044] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0045] There are no particular restrictions on the purity of any of the raw materials used in this invention, but it is preferred to use materials with conventional purity levels used in the field.

[0046] Unless otherwise specified, the apparatus used in this invention employs commonly used devices in the field.

[0047] Example 1

[0048] A method for co-processing lithium-containing waste and fluorine-containing materials includes the following steps:

[0049] (1) Lithium-containing waste (waste nickel-cobalt-manganese lithium battery packs), fluorine-containing materials (polyvinylidene fluoride waste) and calcium-containing materials (CaCl2, which is also used as a chlorine-containing material) are put into the reactor together to react and obtain the reaction products; the reaction temperature is controlled at 600-700℃, and the amount of lithium-containing waste, fluorine-containing materials and calcium-containing materials added is in the mass ratio of 100:20:60;

[0050] (2) The reaction product obtained in step (1) is leached with water as the leaching agent, at a leaching temperature of 30°C and a leaching time of 120 min to obtain the leached reaction product.

[0051] (3) The leaching reaction product from step (2) is subjected to solid-liquid separation to obtain a lithium-containing solution and leaching residue.

[0052] The tests showed that the lithium leaching rate was 97.55% and the F fixation rate was 99.23%.

[0053] Example 2

[0054] A method for co-processing lithium-containing waste and fluorine-containing materials includes the following steps:

[0055] (1) Lithium-containing waste (crushed material containing lithium nickel cobalt manganese oxide cathode material), fluorine-containing material (a mixture of polyvinylidene fluoride and LiPF6 in a mass ratio of 1:0.1), chlorine-containing material (waste polyvinyl chloride plastic) and calcium-containing material (Ca(OH)2) are added together into the reactor to react and obtain the reaction product; the reaction temperature is controlled at 550-650℃, and the amount of lithium-containing waste, fluorine-containing material, chlorine-containing material and calcium-containing material added is in a mass ratio of 100:20:15:30;

[0056] (2) The reaction product obtained in step (1) is leached out. The leaching agent is anhydrous ethanol, the leaching temperature is 15℃, and the leaching time is 60min to obtain the leached reaction product.

[0057] (3) The leaching reaction product from step (2) is subjected to solid-liquid separation to obtain a lithium-containing solution and leaching residue.

[0058] The tests showed that the lithium leaching rate was 98.13%, the F fixation rate in the fluorine-containing materials was 99.23%, and the Cl fixation rate in the chlorine-containing materials was 98.56%.

[0059] Example 3

[0060] A method for co-processing lithium-containing waste and fluorine-containing materials includes the following steps:

[0061] (1) Lithium-containing waste (broken lithium-ion batteries with shells), fluorine-containing materials (waste polytetrafluoroethylene), chlorine-containing materials (waste chlorinated rubber) and calcium-containing materials (CaO) are put into the reactor together to react and obtain reaction products; the reaction temperature is controlled at 550-700℃, and the amount of lithium-containing waste, fluorine-containing materials, chlorine-containing materials and calcium-containing materials added is in the mass ratio of 100:10:20:30.

[0062] (2) The reaction product obtained in step (1) is leached with alcohol (ethanol mass fraction of 50%), the leaching temperature is 15℃ and the leaching time is 90min to obtain the leaching reaction product; (3) The leaching reaction product in step (2) is subjected to solid-liquid separation to obtain lithium-containing solution and leaching residue.

[0063] The tests showed that the lithium leaching rate was 99.06%, the F fixation rate in the fluorine-containing material was 95.44%, and the Cl fixation rate in the chlorine-containing material was 97.27%.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 1 is that no calcium-containing material was added; the other steps are the same as in Example 1. The lithium leaching rate was tested to be 40.31%.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 2 is that no calcium-containing material was added; all other steps are the same as in Example 2. The lithium leaching rate was tested to be only 38.24%.

[0068] Comparative Example 3

[0069] The difference between this comparative example and Example 3 is that no calcium-containing material was added; all other steps are the same as in Example 3. The lithium leaching rate was tested to be only 58.21%.

[0070] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. A method for the co-processing of lithium-containing waste and fluorine-containing materials, characterized in that: Includes the following steps: S1, lithium-containing waste, fluorine-containing materials, chlorine-containing materials and calcium-containing materials are put into the reactor together to react and obtain the first reaction product; S2, leach the first reaction product obtained in step S1 to obtain the second reaction product; S3, the second reaction product obtained in step S2 is subjected to solid-liquid separation to obtain a lithium-containing solution and leaching residue; The reaction temperature in step S1 is 250~1000℃; Among the three raw materials—lithium-containing waste, fluorine-containing materials, and chlorine-containing materials—at least one contains organic matter.

2. The method for co-processing lithium-containing waste and fluorine-containing materials according to claim 1, characterized in that: The lithium-containing waste includes at least one of the following: waste lithium-ion batteries, lithium-ion batteries with casings that have not been dismantled or crushed, materials containing lithium-ion battery cathode materials after physical sorting, lithium-ion battery cathode powder or electrode sheets that are not up to standard, mixtures of lithium-ion battery waste and nickel-containing materials, mixtures of lithium-ion battery waste and cobalt-containing materials, and mixtures of lithium-ion battery waste and manganese-containing materials.

3. The method for co-processing lithium-containing waste and fluorine-containing materials according to claim 1, characterized in that: The fluorine-containing material is at least one of fluorine-containing organic compounds and fluorine-containing inorganic compounds.

4. The method for co-processing lithium-containing waste and fluorine-containing materials according to claim 3, characterized in that: The fluorine-containing inorganic matter is an inorganic matter containing both lithium and fluorine elements; the fluorine-containing organic matter is fluorine-containing organic waste.

5. The method for co-processing lithium-containing waste and fluorine-containing materials according to claim 1, characterized in that: The chlorine-containing material is at least one of the following: an organic solution containing chlorine, an organic polymer containing chlorine, an organic compound containing chlorine, and an inorganic compound containing chlorine. The calcium-containing material is at least one of CaCl2, CaO, CaSO4, Ca(OH)2, Ca(NO3)2, CaCO3, and CaC2.

6. The method for co-processing lithium-containing waste and fluorine-containing materials according to claim 5, characterized in that: Organic solutions containing chlorine are organic waste solutions containing chlorine; organic polymers containing chlorine are organic waste polymers containing chlorine; organic matter containing chlorine is organic waste containing chlorine.

7. The method for co-processing lithium-containing waste and fluorine-containing materials according to claim 1, characterized in that: In step S1, the addition amounts of lithium-containing waste, fluorine-containing materials, chlorine-containing materials, and calcium-containing materials are in a mass ratio of 100:(2~80):(0~80):(1~80).

8. The method for co-processing lithium-containing waste and fluorine-containing materials according to claim 1, characterized in that: In step S2, the leaching agent used in the leaching process is at least one of water and ethanol; the leaching temperature is 15~100℃, and the leaching time is ≥10min.

9. A method for co-processing lithium-containing waste and fluorine-containing materials according to claim 1, characterized in that: In step S3, the lithium-containing solution can be used for the production of lithium compounds; If lithium-containing waste contains at least one of nickel, cobalt, or manganese, products containing the corresponding elements can be extracted from the leaching residue.