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

Abstract

The invention relates to resource recovery and environmental protection, and discloses a lithium-containing waste and fluorine-containing material co-processing method which comprises the following steps: putting a lithium-containing waste, a fluorine-containing material, a chlorine-containing material and a calcium-containing material into a reactor together, and reacting to obtain a first reaction product; leaching the first reaction product to obtain a second reaction product; and the second reaction product is subjected to solid-liquid separation, and a lithium-containing solution and leaching residues are obtained. According to the method disclosed by the invention, a method for co-processing the lithium-containing waste, the fluorine-containing organic waste and the chlorine-containing organic waste is creatively provided, and the calcium-containing material is added in the thermal reduction process, so that lithium in the lithium-containing waste is efficiently recovered, and the problem of environmental pollution caused by chlorine / fluorine in the fluorine-containing organic waste and the chlorine-containing organic waste is solved; chlorine is converted into a LiCl product form for recovery, and fluorine is fixed in a CaF2 form.

Description

Technical Field

[0001] The invention relates to the technical field of resource recovery and environmental protection, and in particular to a method for co-disposing lithium-containing waste materials and fluorine-containing materials. Background Art

[0002] Lithium-ion batteries are widely used due to their good cycle performance and high energy density, especially in the field of new energy vehicles, where they have been rapidly developed and installed capacity has increased year by year. However, due to their limited lifespan (usually 3-5 years), a large number of lithium-ion batteries will be scrapped. These scrapped lithium-ion batteries contain a large amount of valuable metals and have a high recycling value, but at the same time, their composition also contains a large amount of environmentally harmful substances, such as organic matter such as binders, diaphragms and electrolytes. Therefore, how to safely and effectively recycle waste lithium-ion batteries has become a major problem.

[0003] At present, there are two main methods for recycling waste lithium-ion batteries: pyrometallurgical recycling and hydrometallurgical recycling. Among them, the pyrometallurgical recycling process has high energy consumption, low product purity, and greater environmental pollution; in contrast, the hydrometallurgical recycling process has the advantages of being environmentally friendly and having high recycling efficiency, and has a broad application prospect. Among the many hydrometallurgical recycling processes for waste lithium-ion batteries, the thermal reduction-water leaching method is considered to be the most promising method. This process can make full use of the organic matter (binder, electrolyte, and diaphragm) of the battery itself as a reducing agent, and can convert waste lithium-ion batteries into soluble lithium salts, and convert high-valent oxides of nickel, manganese, and cobalt into low-valent 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 leaching to effectively recover lithium from the thermal reduction product. This method is more environmentally friendly and has lower costs than the acid leaching method. However, this method also has great limitations. For example, polyvinylidene fluoride (PVDF) is a commonly used binder in lithium-ion battery materials. If it is used as a reducing agent in the thermal reduction process, it will produce water-insoluble LiF, which will affect the subsequent leaching efficiency and greatly reduce the recovery rate of Li. On the other hand, the process will also produce a large amount of fluorine-containing harmful gases such as HF, PF5, POF3, etc., which seriously pollute the environment.

[0004] In response to the above problems, the Chinese invention patent "A method for pyrolysis and defluorination of waste lithium batteries" with publication number CN111495925A, after two crushing and sorting, fluorine and chlorine are removed by pyrolysis in a closed rotary kiln and absorbed in situ by a harmful gas absorbent, and the exhaust gas is subsequently condensed, dusted, sprayed, adsorbed and ignited. However, the process is cumbersome, and the fluorine and chlorine are not converted into product substances for recovery.

[0005] On the other hand, in addition to the fluorine-containing substances contained in the waste lithium-ion batteries themselves, a large amount of fluorine-containing organic waste is generated every day around the world, such as waste polytetrafluoroethylene (PTFE), waste polyperfluoroethylene propylene (FEP), waste fusible polytetrafluoroethylene (PFA), waste polyvinyl fluoride (PVF) and other fluorine-containing waste plastics. These fluorine-containing organic wastes are mostly difficult to degrade organic matter, or even persistent organic pollutants (such as perfluoroalkyl and polyfluoroalkyl compounds), which are extremely harmful to the environment.

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

[0007] The purpose of the present invention is to provide a method for the coordinated disposal 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 emission of fluorine.

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

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

[0010] S1, 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;

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

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

[0013] Preferably, the lithium-containing waste is at least one of waste lithium-ion batteries, lithium-ion batteries with shells that have not been disassembled or crushed, materials containing lithium-ion battery positive electrode materials that have been physically sorted (disassembly, crushing, screening, etc.), unqualified lithium-ion battery positive electrode powder or pole pieces, 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 at least include lithium-ion battery positive electrode materials.

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

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

[0017] Further preferably, at least one of the three raw materials, namely, lithium-containing waste, fluorine-containing material and chlorine-containing material, contains organic waste.

[0018] Preferably, the fluorine-containing material is at least one of a fluorine-containing organic substance and a fluorine-containing inorganic substance.

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

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

[0021] Specifically, the addition of inorganic substances containing both lithium and fluorine elements can further increase the lithium content in the thermal reduction output material, thereby improving the economic benefits of the process. Inorganic substances containing both lithium and fluorine elements include LiF, LiPF6, and the like.

[0022] The benefits of adding fluorine-containing organic waste are as follows: ① The thermal decomposition of fluorine-containing organic matter produces reducing gases and substances, which enhance the reduction of lithium-ion battery positive electrode materials in lithium-containing waste; ② The lithium-containing waste and fluorine-containing organic waste are treated synergistically, and the coordinated treatment of the two types of waste is achieved through one device, without the need for new hazardous waste treatment production lines.

[0023] Preferably, the chlorine-containing material is at least one of an organic solution containing chlorine, an organic polymer containing chlorine, an organic substance containing chlorine, and an inorganic substance 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 element is an organic waste solution containing chlorine element; the organic polymer containing chlorine element is an organic waste polymer containing chlorine element; and the organic matter containing chlorine element is an organic waste containing chlorine element.

[0026] When the chlorine-containing material in the present invention is used, pure raw materials containing chlorine elements commonly used in industry (non-waste) can be used; but related waste can also be used. The use of waste not only reduces the use cost, but also protects the environment, and has better environmental benefits.

[0027] Further preferably, the calcium-containing material is CaCl2, and the use of CaCl2 not only provides a chlorine-containing material, but also provides a calcium-containing material. When CaCl2 is used as the calcium-containing material, other chlorine-containing materials can no longer be used. The calcium element is added to the calcium-containing material to fix the fluorine in the fluorine-containing material, and also fix the fluorine-containing substances (such as lithium hexafluorophosphate electrolyte, PVDF binder) of the waste lithium ion battery itself.

[0028] The organic polymer containing chlorine element can be any known one in the common knowledge, specifically plastic containing chlorine element, rubber containing chlorine element, resin containing chlorine element, etc. The organic polymer waste containing chlorine element can be any known one in the common knowledge, specifically plastic waste containing chlorine element, rubber waste containing chlorine element, resin waste containing chlorine element, etc.

[0029] Chlorine-containing materials include chlorine-containing organic matter. The use of chlorine-containing organic matter not only makes full use of the chlorine element therein, but also utilizes the reducing property generated by the thermal decomposition of the chlorine-containing organic matter. The reducing property generated by the thermal decomposition of the chlorine-containing organic matter is stronger than the reduction conversion of the transition metal oxides in the waste lithium batteries, and can release lithium.

[0030] Preferably, in step S1, the addition amounts of lithium-containing waste, fluorine-containing material, chlorine-containing material and calcium-containing material are carried out in a mass ratio of 100:(2-80):(0-80):(1-80); and the reaction temperature of step S1 is 250-1000°C.

[0031] In order to ensure the reaction effect and improve the lithium leaching rate, the reaction temperature of step S1 is preferably 400-800°C.

[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° C., and the leaching time is ≥10 min.

[0033] Further 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 the lithium-containing waste contains at least one of nickel, cobalt and 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 an oxygen-free pyrolysis furnace, an oxygen-containing pyrolysis furnace, a rotary kiln, a tunnel kiln, a rotary kiln, and a roasting furnace;

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

[0038] The organic matter in the fluorine-containing material or the chlorine-containing material (preferably the related organic waste) can reduce the high-valent nickel, cobalt and manganese contained in the lithium-containing waste to low-valent oxides and metals. At the same time, in the presence of the calcium-containing material, the lithium element in the lithium-containing waste is converted into LiCl that is soluble in water, ethanol, and a mixture of water and ethanol (alcohol), and the F in the fluorine-containing material is fixed as CaF2. Therefore, after thermal reduction-leaching, lithium can be selectively leached, and fluorine is fixed in the leached residue. This not only avoids the generation of insoluble LiF, improves the subsequent lithium recovery rate, but also solves the environmental pollution problem caused by the fluorine-containing material.

[0039] Beneficial effects:

[0040] (1) The method of the present invention creatively proposes a method for the coordinated disposal 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 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, achieves the effect of "turning waste into treasure", and alleviates the current environmental crisis to a great extent.

[0042] (3) The method of the present invention creatively proposes a method for selectively extracting lithium using alcohol (a mixture of water and ethanol). Since the boiling point of alcohol is significantly lower than that of water, and the heat capacity is also significantly lower than that of water, the lithium-containing solution can be subsequently evaporated and crystallized to recover lithium chloride, and the energy consumption for lithium extraction is significantly reduced. DETAILED DESCRIPTION

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

[0044] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0045] There is no particular limitation on the purity of all raw materials in the present invention, and the present invention preferably adopts the conventional purity used in the art.

[0046] The devices used in the present invention are not particularly limited and can be any of the commonly used devices in the art.

[0047] Example 1

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

[0049] (1) putting lithium-containing waste (waste nickel-cobalt-manganese-oxide lithium complete battery pack), fluorine-containing material (polyvinylidene fluoride waste) and calcium-containing material (CaCl2, also used as chlorine-containing material) into a reactor to react and obtain a reaction product; controlling the reaction temperature to 600-700° C., and adding the lithium-containing waste, fluorine-containing material and calcium-containing material in a mass ratio of 100:20:60;

[0050] (2) leaching the reaction product obtained in step (1), using water as the leaching agent, the leaching temperature being 30° C., and the leaching time being 120 min, to obtain a leaching reaction product;

[0051] (3) subjecting the leaching reaction product of step (2) to solid-liquid separation to obtain a lithium-containing solution and leaching residue.

[0052] After testing, the lithium leaching rate was 97.55% and the F fixation rate was 99.23%.

[0053] Example 2

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

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

[0056] (2) leaching the reaction product obtained in step (1), wherein the leaching agent is anhydrous ethanol, the leaching temperature is 15° C., and the leaching time is 60 min to obtain a leaching reaction product;

[0057] (3) subjecting the leaching reaction product of step (2) to solid-liquid separation to obtain a lithium-containing solution and leaching residue.

[0058] After testing, the leaching rate of lithium was 98.13%, the fixation rate of F in the fluorine-containing material was 99.23%, and the fixation rate of Cl in the chlorine-containing material was 98.56%.

[0059] Example 3

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

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

[0062] (2) leaching the reaction product obtained in step (1), wherein the leaching agent is alcohol (the mass fraction of ethanol is 50%), the leaching temperature is 15° C., and the leaching time is 90 minutes to obtain a leaching reaction product; (3) performing solid-liquid separation on the leaching reaction product of step (2) to obtain a lithium-containing solution and a leached residue.

[0063] After testing, the leaching rate of lithium was 99.06%, the fixation rate of F in the fluorine-containing material was 95.44%, and the fixation rate of Cl 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 is added, and the other steps are the same as those of Example 1; the lithium leaching rate is 40.31% after detection.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 2 is that no calcium-containing material is added, and the other steps are the same as Example 2. The lithium leaching rate is only 38.24% after testing.

[0068] Comparative Example 3

[0069] The difference between this comparative example and Example 3 is that no calcium-containing material is added, and the other steps are the same as Example 3. The lithium leaching rate is only 58.21% after testing.

[0070] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A method for co-disposing lithium-containing waste materials and fluorine-containing materials, characterized in that: The following steps are involved: S1, 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; S2, leaching the first reaction product obtained in step S1 to obtain a second reaction product; S3, performing solid-liquid separation on the second reaction product obtained in step S2 to obtain a lithium-containing solution and leached residue.

2. The method for co-disposal of lithium-containing waste and fluorine-containing materials according to claim 1, characterized in that: The lithium-containing waste is at least one of waste lithium-ion batteries, lithium-ion batteries with shells that have not been disassembled or crushed, materials containing lithium-ion battery positive electrode materials that have been physically sorted, unqualified lithium-ion battery positive electrode powder or pole pieces, 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.

3. The method for co-disposal of lithium-containing waste and fluorine-containing materials according to claim 1, characterized in that: Among the three raw materials, namely, lithium-containing waste, fluorine-containing materials and chlorine-containing materials, at least one of them contains organic matter.

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

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

6. The method for co-disposal of lithium-containing waste and fluorine-containing materials according to claim 3, characterized in that: The chlorine-containing material is at least one of an organic solution containing chlorine, an organic polymer containing chlorine, an organic substance containing chlorine, and an inorganic substance containing chlorine; The calcium-containing material is at least one of CaCl2, CaO, CaSO4, Ca(OH)2, Ca(NO3)2, CaCO3, and CaC2.

7. The method for co-disposal of lithium-containing waste and fluorine-containing materials according to claim 6, characterized in that: An organic solution containing chlorine is an organic waste solution containing chlorine; an organic polymer containing chlorine is an organic waste polymer containing chlorine; and an organic matter containing chlorine is an organic waste containing chlorine.

8. The method for co-disposal of lithium-containing waste and fluorine-containing materials according to claim 1, characterized in that: In the step S1, the addition amount of lithium-containing waste, fluorine-containing material, chlorine-containing material and calcium-containing material is 100: (2-80): (0-80): (1-80) by mass ratio; the reaction temperature of the step S1 is 250-1000°C.

9. The method for co-disposal of 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° C., and the leaching time is ≥10 min.

10. The method for co-disposal of 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 the lithium-containing waste contains at least one of nickel, cobalt and manganese, products containing the corresponding elements can be extracted from the leaching residue.