Process and system for obtaining graphite

Abstract

The present invention relates to a process for obtaining graphite, and optionally metals of value, which are preferably selected from at least one of the metals of the first and / or the third main group and / or at least one of the metals from the 7th to 11th secondary group, from lithium-ion batteries. The invention also relates to a corresponding system (71).

Description

[0001] Process and plant for the extraction of graphite

[0002] The present invention relates to a process for extracting graphite, and optionally valuable metals, which are preferably selected from at least one of the metals of the first and / or third main group and / or at least one of the metals of transition groups 7 to 11, from lithium-ion batteries; as well as to a plant for extracting graphite, and optionally valuable metals, from lithium-ion batteries, which is preferably designed to carry out the process according to the invention.

[0003] Due to their increasing use as energy sources in electric vehicles, lithium-ion batteries will soon be generated in large quantities during production and as waste at the end of their service life. These batteries are made from a variety of valuable materials combined. These are primarily:

[0004] Plastics, ferrous metals, copper, aluminum, graphite as anode material, metal oxides as cathode material, lithium, cobalt, nickel, manganese and other rare valuable materials as well as electrolyte.

[0005] Approximately 50% of battery modules consist of so-called "black mass," which contains the particularly valuable raw materials and consists primarily of fine graphite and lithium metal oxides in the 0.5 to 10 pm range. Nickel, manganese, copper, and cobalt are also considered particularly valuable components.

[0006] The battery blocks are interconnected in such a way that controlled disassembly, for example, by loosening a screw connection, is practically impossible. Furthermore, widely varying formats are commercially available. Therefore, the manufacturer's instructions must always be observed before and during the discharging and disassembly process. Depending on the battery type, it may even be necessary to activate special devices within the battery to disconnect the battery terminals in order to complete the discharge. After opening the battery and discharging, the components must be separated. The metals and plastics of the housing can be sorted separately and recycled into the recycling economy, with suitable recycling processes already in place.

[0007] The remaining battery blocks consist of individual battery cells and / or modules. Depending on the battery design, it is possible to simply separate the cells; however, there are also batteries where separating the battery blocks is very complex, so that to date there is no satisfactory process for recycling the blocks or cells. The unpleasant characteristic of these batteries is that complete discharge is very time-consuming, and after a discharge cycle the batteries regain voltage, i.e. a state of charge, after a short time. A battery that is not fully discharged will usually suffer a short circuit when opened, which can ignite the electrolyte due to the heat. The consequences can be unpredictable explosions or even fires.

[0008] The solutions known to date from the state of the art sometimes attempt to thermally recycle the batteries while recovering the metals. However, plastics, electrolyte, and lithium are lost completely or in large quantities. In some processes, the battery cells are crushed and transferred directly to the wet-chemical process. The battery cells are only inadequately separated before the subsequent wet-chemical precipitation process. This doubles the amount to be processed in the wet-chemical process. One such wet-chemical process is described, for example, in EP 3 670 686 A1.

[0009] During thermal recycling, valuable raw materials in the black mass, such as lithium, graphite, nickel, cobalt, and other metals, are also lost. This creates a significant burden on the precipitation chemistry or wet-chemical process due to metallic and other residues from the battery casings and conductors.

[0010] DE 10 2011 082 187 A1 discloses a method for comminuting batteries containing LiPF6. The method involves subjecting the battery to a comminution process using at least one tool that mechanically acts on the battery. The comminution process takes place in an ambient fluid surrounding the battery that contains at least one alkaline earth metal. The ambient fluid is an aqueous solution containing calcium or magnesium, which exist as basic hydroxides Ca(OH)2 or Mg(OH)2, respectively, and react in aqueous solution with the hydrogen fluoride (HF for short) produced during the decomposition of LiPF6 to form sparingly soluble CaF2 or MgF2, respectively, and are thus bound.

[0011] Based on the aforementioned problems of the methods known from the prior art, the object of the present invention is to provide an effective process in which valuable raw materials for the recycling economy, in particular graphite and possibly valuable metals, can be obtained from batteries that either originate from production rejects or have reached the end of their service life.

[0012] Description of the invention

[0013] According to the invention, the object is achieved by a method having the features of patent claim 1.

[0014] The process according to the invention for obtaining graphite, and optionally valuable metals, which are preferably selected from at least one of the metals of the first and / or the third main group and / or at least one of the metals of the 7th to 11th subgroup, from lithium-ion batteries; comprises at least one step in which the batteries, which have a residual charge of a maximum of 30%, are crushed in a crushing device with the addition of water, so that a mixture of crushed batteries and water is obtained; wherein the mixture comprising the crushed batteries and the water is separated into a first aqueous graphite-enriched fraction, which optionally also contains metal oxides, and a second non-aqueous graphite-depleted fraction; wherein the first aqueous graphite-enriched fraction is then freed from water, so that a dried graphite-containing fraction, which optionallyalso contains metal oxides; and wherein the second non-aqueous graphite-depleted fraction is passed through a separation device, in particular a zigzag separator, and divided into a heavy fraction containing particulate components with a bulk density of at least 0.02 kg / m. 3 and into a light fraction containing particulate components with a bulk density of maximum 0.40 kg / m 3 Alternatively, the second non-aqueous, graphite-depleted fraction can be passed through a separator that separates the two fractions using centrifugal forces in a cyclone air flow.

[0015] The proposed process is characterized by its high efficiency, allowing more than approximately 95% of the valuable raw materials to be recycled in a highly energy-efficient manner. Surprisingly, it has been shown that complete discharge of the batteries is not necessary for the subsequent separation process, which can significantly reduce the effort required in the pre-processing phase. The energy recovered during partial discharge can also be advantageously reused.

[0016] Wet crushing of batteries minimizes the risk of deflagrations or even fires. The water immediately reduces the temperature, preventing a chemical chain reaction. Therefore, adding a sufficient amount of water during battery crushing not only prevents excessive heating, but also surprisingly demonstrates that harmful hydrogen fluoride is not released, or at least not in a measurable concentration. It is currently assumed that the hydrolysis reaction of LiPF6 in pure water, in contrast to hydrolysis in contaminated electrolyte water, proceeds very slowly, as shown below:

[0017] First, Li PF6 decomposes in water according to the equation:

[0018] Only in the subsequent reaction Hydrogen fluoride would be produced. In contrast to the prior art, the process according to the invention preferably does not use setting agents to set the LiPFe, as described, for example, in DE 10 2011 082 187 A1. A further advantage of the process according to the invention is that the mechanical / fluid-technical separation of the valuable raw materials (also referred to as "black mass") from the metals and plastics requires significantly less material for subsequent process steps, allowing the corresponding plant to be operated more effectively and cost-effectively.

[0019] Further advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically expedient manner and can define further embodiments of the invention. Furthermore, the features specified in the claims are further specified and explained in the description, where further preferred embodiments of the invention are presented.

[0020] The second non-aqueous graphite-depleted fraction, which is passed through a separating device and separated into the heavy fraction and the light fraction, may preferably comprise particulate components with a size of > 5000 pm, more preferably with a size of > 4000 pm, even more preferably with a size of > 3000 pm, further preferably with a size of > 2000 pm.

[0021] According to a preferred embodiment of the present invention, the heavy fraction, which comprises a graphite-containing secondary fraction, is first crushed and then separated into pure fractions. This is preferably done using a further crushing device, in particular an impact mill, to which the heavy fraction is then fed and crushed.

[0022] The separation into the pure fractions can preferably be carried out using a sieve cascade designed to separate the comminuted heavy fraction into a first medium fraction with metal-containing particles with a size in the range of approximately 250 pm to approximately 100 pm, a coarser fraction with plastic-containing particles with a size of more than 250 pm, and a third finer fraction with graphite-containing particles with a size of less than 100 pm. The medium fraction is then preferably separated, optionally using an air separation table and / or a magnetic separator, into pure metallic fractions in order to obtain, for example, the metals copper, aluminum, and iron in pure form.

[0023] A preferred development of the method provides that the aerosol which is produced during the separation process and / or the comminution process and which contains part of the graphite-containing secondary fraction is sucked off and the part of the graphite-containing secondary fraction contained therein is separated, in particular filtered off.

[0024] In summary, the previously mechanical separation process can be described as follows. The metals and plastics are separated in a first separation process that utilizes density differences. Transverse air currents in free fall ensure the separation of the heavier metals from the lighter plastic and film residues. A further comminution device, in particular an impact mill, removes the black mass adhering to the metals. An extraction system captures the dust, which essentially consists of black mass. A sieve cascade preferably separates the components according to their size. Magnetic separators, for example, can be used to separate the ferromagnetic components. The remaining metals can be separated from one another, for example, by utilizing density differences using an air separation table or the like.The metals are preferably collected separately and can be fed into the recycling economy. The lighter plastics are also preferably collected and can be fed into the recycling economy. The black mass is also preferably collected and then sent for further processing.

[0025] Preferably, the batteries, in particular the battery cells and / or battery modules, are crushed in at least two stages, such that they are initially coarsely pre-crushed in a first stage before being more finely crushed in a subsequent second stage. The selection of the number of crushing stages, for example two, three or more such stages, depends on the size of the material introduced. For complete battery modules with a size of, for example, more than 0.5 m, a three-stage crushing system is advantageous. For individual battery cells or smaller units with a size of less than, for example, 0.5 m, a two-stage system is generally sufficient.

[0026] The clear knife width in the comminution device used in the last comminution stage is preferably less than approximately 12 mm, more preferably less than approximately 9 mm. The clear knife width in the penultimate stage can then be, for example, less than 25 mm, preferably approximately 19 mm. With more than two comminution stages, the clear knife width of the third-to-last stage is, for example, less than approximately 60 mm, preferably less than approximately 45 mm. The specific drive power, i.e. the drive power per throughput in kg / h of battery cells and / or modules for the knife shafts is approximately 50 W / kg of battery cells and / or modules per hour, preferably approximately 80 to 120 W / kg / h.

[0027] The separation into the first and the second fraction can advantageously be carried out via two separate process stages, such that the mixture is first separated in a first process stage, for example in a friction scrubber i) into a first aqueous graphite-enriched fraction comprising particulate components with a size of < 5000 pm, preferably with a size of < 4000 pm, more preferably with a size of < 3000 pm, even more preferably with a size of < 2000 pm and a second non-aqueous graphite-depleted fraction comprising particulate components with a size of > 5000 pm, preferably with a size of > 4000 pm, more preferably with a size of > 3000 pm, even more preferably with a size of > 2000 pm. For example, a shredder can be used for comminution, whereby the first fraction can then be collected in a buffer tank below this shredder and then preferably further separated.Thus, it is preferably provided that ii) the first aqueous graphite-enriched fraction comprising the particulate constituents with a size of < 5000 pm, preferably with a size of < 4000 pm, more preferably with a size of < 3000 pm, even more preferably with a size of < 2000 pm is then separated in a second process stage, in particular by means of a screening stage, into a first aqueous graphite-enriched fraction freed from the particulate constituents, in particular a fraction of particles with a size of less than 500 pm, and a non-aqueous graphite-depleted fraction loaded with the particulate constituents, in particular a fraction of particles with a size of more than 500 pm.

[0028] According to a preferred embodiment of the present invention, the water is preferably used in an amount of 20 to 200 m based on an amount of 1000 kg of batteries per hour. 3 / h. Due to the large and continuous volume flow, the heat generated during the mechanical comminution of the batteries and in the hydrolysis process is immediately dissipated. According to the present invention, comminution is therefore preferably not carried out in a stagnant water reservoir; instead, water is continuously added to and removed from the comminution device in which the comminution takes place, so that the heat generated during the process is also continuously dissipated.

[0029] According to the invention, ordinary tap water at a temperature below room temperature can be used for shredding the batteries, for example. However, it is preferably provided that the water is supplied at a temperature in the range of 5°C to 20°C.

[0030] The water management system can, for example, be designed as a closed-loop system. Thus, the water can be fed to the comminution and / or separation process from a storage tank and collected downstream, for example, where the separated particles are dried, e.g., in a screen press, and then returned to the comminution and / or separation process. Filter systems can also be used to treat the circulating water, so that the exhaust air from a vacuum pump used in the system, for example, is condensed and the condensate can be returned to the storage tank. If additional water is required, it can be supplied from the mains (so-called make-up water). The circulating water can be monitored for various parameters, such as pH, conductivity, biocidity, color, or the like.If necessary, partial quantities of the circulating water can be exchanged. The required circulating water volume for the separation process according to the invention is approximately 20 to 200 m. 3 / h / t batteries. For two-stage shredding, the use of at least 20 m 3 / h / t recommended, preferably at least 50 m 3 / h / t. For three-stage crushing, it is preferable to use at least 50 m 3 / h / t circulating water, particularly preferably about 100 m 3 / h per ton of batteries.

[0031] According to a preferred development of the aforementioned variant of the method, the water obtained during the drying process can be collected, then cooled via a heat exchanger, and subsequently fed back to the comminution device and / or to the mixture comprising the crushed batteries and the water. The water can contain particulate components with a size of, for example, up to 500 pm. Alternatively and / or additionally, the water can also be fed to the process via a friction washer arranged downstream of the comminution device.

[0032] According to a preferred development of the process according to the invention, for further treatment of those fractions which contain the main part of the black mass, preferably the dried graphite-containing fraction and / or the graphite-containing secondary fraction are mixed with concentrated sulfuric acid so that a graphite-containing digestion is obtained, wherein the obtained graphite-containing digestion is then, for example, directly filtered so that graphite and a sulfuric acid solution are obtained.

[0033] The filtered-off graphite can then preferably be purified, in particular rinsed with water. Furthermore, in this preferred variant of the process according to the invention, the sulfuric acid solution, which comprises at least one metal from the first and / or third main group and / or at least one metal from transition groups 7 to 11, can subsequently be wet-chemically separated and / or wet-chemically extracted.

[0034] According to the invention, the black mass obtained in the various separation processes described above is then further processed, preferably in a wet-chemical process, in particular by dissolving it with sulfuric acid until the metals dissolve in the acid. For example, the graphite can be separated, collected, and recycled using a screen press.

[0035] The individual metals, in particular selected from the group comprising lithium, aluminum, manganese, iron, cobalt, nickel, copper, can be precipitated from the acid solution, collected, and fed into the recycling economy, for example by specifically adjusting the acid concentration and / or temperature.

[0036] Acids or special intermediates that are of particular interest to the basic materials industry can also be taken directly from the process.

[0037] The acid is preferably circulated in a recycling system.

[0038] In summary, some preferred measures are listed below which serve the wet-chemical processing of the black mass previously obtained through the separation processes:

[0039] - the black mass and the intermediates can be dissolved by means of sulphuric acid and / or ammonia and / or hydrogen peroxide and / or water and / or organic solvents, which can be used individually or as a solvent mixture;

[0040] - the graphite can be separated from the liquid using a filter press;

[0041] - the liquid can be further processed in a step-by-step process;

[0042] - the liquid can be passed from one process stage to the next;

[0043] - the liquid is preferably circulated;

[0044] - Sulphuric acid, hydrogen peroxide, ammonia and / or organic solvents may be added to ensure chemical reactions and adjust the pH if necessary;

[0045] - the end products are ammonium sulfate and metal sulfates, which can be removed from the system for further recycling;

[0046] - the gases occurring in the individual process stages can be extracted, for example, into a filter system consisting of a wet scrubber and / or a cyclone separator and / or a filter; - the metals present in the liquid can be separated from the liquid as sulfates, in particular stepwise, by adjusting the pH and / or phase separation and / or crystallization;

[0047] - For example, aluminum and iron can be separated together;

[0048] - Copper, for example, can be separated individually;

[0049] - Manganese and cobalt, for example, can initially be processed together and then separated in a subsequent step;

[0050] - Nickel, for example, can be separated individually and / or

[0051] - Lithium can be separated individually.

[0052] When complete car batteries, which are usually designed as relatively large components, are delivered, their construction and electrical connections are fundamentally different, as each automobile manufacturer has its own specific setup. In these cases, additional measures or modifications to the processing process may be useful. For example, car batteries can be identified by manufacturer and specifically discharged and disassembled until the individual battery cells and / or modules are separated. For this purpose, it is recommended to consult the manufacturer's documentation and, if necessary, deactivate auxiliary devices, such as safety devices within the battery for discharging purposes. The battery casing is also disassembled depending on the materials used and sorted and fed into the recycling industry, as are existing conductors, insulators, and other components.

[0053] Discharge can occur, for example, either on the entire car battery or on the individual battery cells and / or modules after assembly. The discharge energy from the batteries is preferably recycled, for example, through direct grid feed-in, buffer storage, or the like.

[0054] The mixer shaft of the separator or shredder used in the first separation process can be operated at a speed of at least 500 rpm, preferably more than 1000 rpm, and more preferably more than 1500 rpm, in order to achieve effective flow conditions and particle movement in the comminution device. The vacuum dryer can, for example, be operated at a pressure of less than 900 mbar. The temperature inside the dryer should preferably be more than 100 °C.

[0055] It is advantageous to use a control system with a process monitoring system that is suitable for recording and / or monitoring the water inflow and / or the quantity of batteries, in particular the battery cells and / or battery modules, and / or the concentration of the black mass.

[0056] The connected extraction systems preferably used in the process according to the invention can collect the dust and pass it through a filter system comprising, for example, a wet scrubber and / or micro filter with activated carbon and / or cyclone separator in order to reduce the environmental impact to a minimum.

[0057] The process according to the invention can be carried out either continuously or discontinuously, whereas the processes known to date from the prior art have always been batch processes. The comminution device according to the invention preferably operates continuously.

[0058] According to a preferred refinement of the process, important acids for the raw materials industry can be removed from the wet-chemical process. In the wet-chemical part of the process, sulfuric acid and / or ammonia are used for the dissolution process. The temperature and acid concentration are preferably adjusted according to the precipitation rules for the respective metals, one after the other in a cascade, whereby separate containers can be used depending on the setting.

[0059] All media used can be recycled, thus reducing resource consumption to a minimum. Energy consumption is significantly lower than with thermal separation processes due to the use of purely mechanical / fluid technology processes.

[0060] In addition to the process described above, the present invention further relates to a plant for the extraction of graphite and, if appropriate, valuable metals, which are preferably selected from at least one of the metals of the first and / or third main group and / or at least one of the metals of groups 7 to 11.Subgroup, made of lithium-ion batteries, comprising at least one comminution device which has a comminution unit which can be flushed with an aqueous medium; at least one separation device downstream of the comminution device in the transport path, which separation device preferably comprises at least one sieve, suitable for separating material obtained in the comminution device into at least two fractions of different particle sizes; at least one drying device downstream of the separation device in the transport path, preferably a filter press, for drying the fraction separated in the first separation device; and at least one further separation device, by means of which lighter and heavier particles are separated from one another by an air flow, wherein this further separation device is downstream of the separation device in the transport path.Preferably, the lighter and heavier particles are separated from each other by a transverse air flow in free fall or by utilizing centrifugal forces in a vortex (cyclone) air flow.

[0061] According to a preferred development of the invention, the plant has a further comminution device arranged downstream of the at least one separation device in the transport path, in particular an impact mill, which serves to further reduce the particles of the previously separated fraction.

[0062] According to a preferred development of the invention, the comminution unit comprises at least two comminution stages arranged one below the other following the force of gravity.

[0063] According to a preferred development of the invention, the at least one first separation device comprises a drying device arranged downstream in the transport path, preferably a filter press or a vacuum dryer, for drying at least one fraction previously separated by means of the separation device.

[0064] According to a preferred development of the invention, the at least one comminution device is designed as an impact mill, wherein this impact mill is arranged downstream of at least one separation device in the transport path and serves to further reduce the particles of a previously separated fraction. According to a preferred development of the invention, the system comprises, downstream of at least one comminution device and downstream of at least one separation device in the transport path, at least one system area in which the particles of at least one previously separated fraction are dissolved in a liquid medium and subsequently subjected to a further separation process, wherein this system area comprises, in particular, a device for sieving and / or pressing and / or adjusting the pH value and / or extracting and / or crystallizing.

[0065] Figure name

[0066] The invention and the technical environment are explained in more detail below with reference to the figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description and / or figures. In particular, it should be noted that the figures and in particular the illustrated proportions are only schematic. The same reference numerals denote the same objects, so that explanations from other figures can be used as a supplement if necessary. They show:

[0067] Figure 1 shows an exemplary schematic description of the preliminary process in the method according to the invention;

[0068] Figure 2 shows an exemplary schematic description of the

[0069] Separation process as part of the method according to the invention;

[0070] Figure 3 shows an exemplary schematic description of another

[0071] Sub-process of the method according to the invention;

[0072] Figure 4 shows an exemplary schematic description of a further sub-process of the method according to the invention;

[0073] Figure 5 shows an exemplary schematic description of the chemical subprocess of the method according to the invention; Figure 6 shows a schematically simplified flow diagram of a first phase of an exemplary process according to the invention;

[0074] Figure 7 is a schematically simplified flow diagram of a subsequent separation process which is part of the method according to the invention;

[0075] Figure 8 is a schematically simplified flow diagram of a further, subsequent separation process, which is also part of the method according to the invention;

[0076] Figure 9 is a schematically simplified flow diagram of a further, subsequent separation process, which is also part of the method according to the invention.

[0077] The sequence of an embodiment of the method according to the invention and the structure of an embodiment of the plant according to the invention for processing batteries for the purpose of recycling the materials contained therein are explained in more detail below.

[0078] The actual process for shredding the batteries and separating their components is preceded by a preliminary process 1, which is described in the schematic representation in Figure 1. In this preliminary process 1, batteries 2 originating from vehicles, which have, for example, reached the end of their service life, and, if applicable, battery cells and / or battery modules that were rejected during production and require disassembly, are first dismantled. These batteries, battery cells, and / or battery modules 2, which are referred to below under the general term "batteries 2," are discharged once (step 4), if necessary after identification of the type (step 3). However, according to the invention, complete discharge is deliberately not provided for, since this - as already explained - is very complex. Furthermore, it was surprisingly discovered that complete discharge is not necessary for the subsequent processing process.As a result, a much larger quantity of batteries 2 can be processed and recycled per unit of time compared to the prior art process, thereby significantly increasing the productivity of a corresponding plant. The electrical energy 5 generated during the partial discharge of the batteries 2 can be used for other purposes. The other components 7 of the batteries 2 that arise during disassembly 6, such as in particular the housing, wiring, fittings, and the like, are sorted and recycled. For this purpose, the different materials are separated and sorted (step 8), and the residual materials 9, which are then sorted according to type, can subsequently be recycled.The batteries, battery cells and / or battery modules 10 separated from the batteries 2 in this preliminary process are then fed to the first sub-process 11, which is described in Figure 2 and is explained below with reference to this illustration.

[0079] The separated batteries, battery cells, and / or battery modules, which are hereinafter referred to under the general term "separated batteries 10," are first mixed with water 12 and preferably crushed in a multi-stage crushing process 13, for example, using a shredder. The water 12 is continuously supplied and serves, among other things, to dissipate the heat generated during the process, preventing the release of hydrogen fluoride (HF). After the crushing process or step 13, the mixture comprising the crushed batteries and the water can be separated into a first aqueous, graphite-enriched fraction 15 and a second, non-aqueous, graphite-depleted fraction 16 (separation step 14), for example, by centrifuging and spinning the mixture.

[0080] The first aqueous graphite-enriched fraction 15 obtained according to the separation step 14, which contains the majority of the black mass, preferably comprises particulate components with a size of <3 mm, whereas the second non-aqueous graphite-depleted fraction 16 preferably comprises particulate components with a size of >3 mm. The first aqueous graphite-enriched fraction 15 can be directly freed of water according to a drying step 17, so that a dried graphite-containing fraction 18 containing the majority of the black mass is obtained.

[0081] For the purposes of the present invention, "black mass" refers to the most valuable raw materials, which can subsequently be separated in a wet-chemical process, as shown in Figure 5. However, the first aqueous graphite-enriched fraction 15 can also be initially separated into a first aqueous graphite-enriched fraction 19, freed from particulate constituents, and a non-aqueous graphite-depleted fraction 20, loaded with particulate constituents. For example, this fraction can be screened in several steps, first coarsely (step 21) and then finely (step 22), to obtain the non-aqueous graphite-depleted fraction 20, loaded with particulate constituents. The first aqueous fraction 19, which is enriched in graphite and freed from the particulate components, can then be freed from the water, for example by pressing (step 23).The contaminated water 24 can, after it has been cleaned and treated by suitable measures if necessary (step 25), be returned to the water cycle and reused in the process.

[0082] The second non-aqueous graphite-depleted fraction 16, which may, for example, still contain moist small parts with a particle size in the range of about 3 mm to about 10 mm as well as foils and metals, is fed to a second sub-process 26 for processing, which is shown in Figure 3 and is explained in more detail below with reference to this illustration.

[0083] According to the illustration in Figure 3, the second non-aqueous graphite-depleted fraction 16 is separated into a light and a heavier fraction 28, 29 by means of a further separation step 27. For this purpose, a cross-air flow can be used, for example, when the particles are in free fall. The aerosol 31 generated during the separation step or process 27 and containing a portion of a first graphite-containing secondary fraction 33 can be removed from the separation step 27 by a suction step 30 and filtered via a separation step 32, so that the portion of the first graphite-containing secondary fraction 33 contained therein is separated, in particular filtered off.

[0084] The heavier metallic particles (heavy fraction 29), which contain the majority of the first graphite-containing secondary fraction 33, can, after the separation described above in separation step 27, be fed to a comminution device, in particular an impact mill 34, in which further comminution takes place. The different fractions obtained in this way can then be separated from one another by a sieving process 35, namely into a first medium fraction with particles having a size in the range from approximately 250 pm to approximately 100 pm, a coarser fraction with particles having a size of more than 250 pm, and a third finer fraction with particles having a size of less than 100 pm. The third finer fraction then comprises the majority of the first graphite-containing secondary fraction 33, which, after passing through the separation step orThe black mass fraction resulting from the filter system 32 is combined and can also be fed to the wet chemical treatment (see Figure 5).

[0085] The coarser fraction shown in Figure 3 (> 250 pm) generally contains predominantly plastics 37. This can be collected 38 and returned to a recycling system 39, as also shown in Figure 3. The medium fraction, however, can be further separated, for example, using an air separation table and / or a magnetic separator 40, in order to collect the metals copper, aluminum, and iron in a sorted manner 41.

[0086] Figure 4 shows a third sub-process 42, which describes the further processing of the non-aqueous, graphite-depleted and particulate-laden fraction 20 (see Figure 2). Reference is made to this sub-process below.

[0087] This fraction 20 can first be dried in a drying device, in particular in a vacuum dryer 43, wherein the resulting condensate water 44 can be fed to the water circuit 25. After the drying device 43, the material can be fed to a comminution device, in particular an impact mill 45, in which further comminution takes place. The comminution step is then followed by a screening process 46 to separate the resulting fractions. The multiple fractions (for example, three) can be of the same order of magnitude as in the screening process 35 previously described with reference to Figure 3.Through the sieving process 46, for example, a first medium fraction comprising particles with a size in the range of approximately 250 pm to approximately 100 pm, a coarser fraction comprising particles with a size of more than 250 pm, and a third finer fraction comprising particles with a size of less than 100 pm can be obtained. This third finer fraction comprises a further black mass-containing fraction 47, which in this case may contain water. The water can be removed by means of a separation step, for example by sieving and pressing 48. The then dried black mass fraction 49 (=second graphite-containing secondary fraction) can be combined directly or, if necessary, with the remaining fractions 18, 33 and then fed to the wet chemical processing (see Figure 5).

[0088] The coarser fraction (> 250 pm) generally contains predominantly plastics 50. This can be collected separately (step 51) and also fed into the recycling system 39. The medium fraction, however, can be further separated, for example, using an air separation table and / or a magnetic separator 52, in order to collect the metals copper, aluminum, and iron separately and also feed them into the recycling system 39.

[0089] The aerosol 55 generated during the comminution step 45 and containing a portion of the second graphite-containing secondary fraction 49 can be extracted therefrom by a suction step 53 and filtered through a separation step 56, so that the portion of the second graphite-containing secondary fraction 49 contained therein is separated, in particular filtered off. The black mass fraction 54 resulting after passing through the separation step or filter system 56 can also be combined directly or, if necessary, with the remaining fractions 18, 33, 49 and then subjected to wet-chemical processing (see Figure 5).

[0090] The process of wet chemical treatment (fourth sub-process 57) of the various black mass-containing fractions 18, 33, 49, 54 is explained in more detail below with reference to Figure 5.

[0091] The individual or possibly combined black mass-containing fractions 18, 33, 49, 54 can be dissolved, for example, using aqueous sulfuric acid, ammonia, hydrogen peroxide, and / or organic solvents 58 (step 59) and then subjected to a sieving and / or filtering process 60. Graphite 61 can be separated, collected 62, and returned to the recycling system 39. The metals 63 obtained after this separation are in a solution whose pH is adjusted accordingly, depending on the metal (step 64). This can then be followed by an extraction 65, in which the metals can be obtained, for example, as metal sulfates and crystallized or extracted again. The pH adjustment (step 64) can be carried out in several stages, depending on the metal and the extraction process.The metal sulfates 66 of the individual metals from each stage can then be collected separately and sorted (step 67) and thus obtained as raw materials 68 for basic industries. Surplus ammonium sulfate 69 can be removed as shown in Figure 5 and sent for recycling 70.

[0092] Below, an exemplary structure of a system 71 for the separation process described above is described in detail using several schematic flow diagrams, initially with reference to Figure 6. As already explained, the batteries 2 are first sorted, disassembled, and discharged in the preliminary process 1. The then obtained separated batteries, battery cells, and / or battery modules 10 are fed via a conveying device, in particular a conveyor belt 72 ascending in the conveying direction, to a comminution device 73, for example a shredder, and are comminuted as a whole in two stages with the addition of water 12. For this comminution process, water 12 is continuously supplied to the comminution device 73 via a line 74, which water enters the interior of the comminution device 73 via an inlet.Below the lower end region of the comminution device 73 is the inlet end 75 of a friction washer 76, which comprises a conveyor screw equipped with paddles. The friction washer 76 comprises a screen arranged below the inclined conveyor screw. When the comminuted material, in particular the mixture comprising the crushed batteries and the water, is conveyed by the conveyor screw from the inlet end 75 to the axially opposite outlet end 77 of the conveyor screw (from left to right in the drawing), the finer material with a particle size of, for example, less than 1 to less than 3 mm (for example, the first aqueous graphite-enriched fraction 15) falls through the screen and reaches a buffer tank 79 via a line 78 below the inlet end 75.The coarser material with a particle size of, for example, more than 1 to more than 3 mm (for example, the second non-aqueous graphite-depleted fraction 16), on the other hand, is transported via the conveyor screw arranged in the friction washer 76 to its outlet end 77, falls downward through the opening there, and passes via line 80 into a silo 81, from which it is fed to the second sub-process 26. This will be explained in more detail later with reference to Figure 8.

[0093] The fraction of finer particles with a size of, for example, less than 1 to less than 3 mm is conveyed by a pump 82 to a sieve 83, by means of which a further separation into the two fractions 19, 20 takes place, namely a fraction 19 with a particle size of less than, for example, 500 pm, which contains the largest part, for example, about 95% of the black mass and about 5% metals, and a fraction 20 with a particle size of more than, for example, 500 pm, which contains metals such as copper and aluminum as well as plastics with adhering black mass. This fraction 20 is fed via line 84 and the screw conveyor 85 to the third sub-process 42, which will be explained in more detail later with reference to Figure 9.

[0094] The separation process 11 illustrated by way of example in system 71 can thus be summarized as follows. The shredder 73, to which water 12 and separated batteries, battery cells, and / or modules 10 are fed, also serves as a separator in which an initial separation of the materials takes place. Water is supplied to the shredder 73 to essentially remove the black mass from the other components of the separated batteries 10 and then transport them away. The shredder 73 is a largely closed container combined with the housing of the friction washer 76, which is arranged below the container and contains the conveyor screw. The combined device has two offset outlets. The first outlet, located in the inlet area 75 of the friction washer 76, is connected to the line 78.The second outlet, which is located in the outlet area 77 of the friction washer 76, is connected to line 80. The mesh size of the sieve of the friction washer 76, which is located around the conveyor screw, can be used to determine the size of the smaller particles that the sieve allows to pass through to the first outlet. In the shredder 73, the small parts are swirled in the water so that the black mass is rinsed away. The collision of the small parts with the housing of the shredder 73 and the flow guides during the transport of the particles in the device additionally remove the black mass from the battery parts. The conveyor screw in the friction washer 76 below the shredder 73 comprises at least one mixer shaft with radially arranged levers, which, due to their shape, in addition to the swirling, force a direction of movement from the inlet end 75 to the outlet end 77 with the second outlet.As a result of the separation process in the shredder / separator 73, the metal and plastic parts leave the device via the second outlet in the exit area 77 of the conveyor screw, while the black mass falls through the sieve with the water and leaves the device via the first outlet in the entrance area 75 of the conveyor screw. This material is then further separated via the additional sieve 83, through which larger particles, especially plastic particles with a size of, for example, more than 500 pm, are separated from the black mass transported in the water. The mesh size of the additional sieve 83 can vary so that, for example, smaller particles in the range of approximately 100 pm to approximately 1 mm, preferably in the range of approximately 100 pm to approximately 500 pm, are separated.

[0095] The finer fraction of particles with a size of less than 500 pm enters the tank 86 and is then fed by means of a further pump 87 via the line 88 to a further separation process of the first sub-process 11, which is explained in more detail below with reference to Figure 7.

[0096] This finer fraction 19 is conveyed, according to the flow diagram of Figure 7, through line 88 into a circulation tank 89 equipped with a stirrer. A partial flow leaves this circulation tank 89 via line 90 and is conveyed to a filter press 91, where drying takes place by separating water. Organic exhaust gases, which are fed to the filter press 91 via line 92, can be used for heating. In addition, compressed air is supplied to the filter press 91 via line 93. A partial flow of this particle fraction diluted with water can be conveyed via line 94 by means of the pump 95 through a heat exchanger 96 and from there returned to the process according to Figure 6 via the return line 97. Hot tap water flows through the heat exchanger 96 in countercurrent, and this water reaches the heat exchanger 96 via line 98, so that the returned material flow can be preheated in this way.The product of the process shown in Figure 7 is the dried black mass-containing fraction 18, which leaves the filter press 91 via line 99 and can be temporarily stored in a drum 100. Here, the black mass is already present at a quite high degree of purity, for example, approximately 95%, with a residual moisture content in the range of approximately 20% to 30%. This black mass-containing fraction 18 can be used as feedstock for a further wet-chemical treatment process, which is shown in Figure 5 and has already been described above.

[0097] The further separation process 26 relating to the fraction of coarse material 16 accruing after the first shredding process according to Figure 6 is explained in more detail below with reference to Figure 8. This separation process 26 primarily serves to separate the separator film of the separated batteries 10 from the plastic and metal particles. The coarse fraction passes from the silo 81 via line 101 to a cyclone 102, where centrifugal separation takes place. The fraction is then fed to a zigzag separator 103, where the metals and plastics are separated using a process that exploits density differences. During free fall, transverse air currents ensure that the heavier metals are separated from the lighter plastic residues and film residues. The black mass adhering to the metals can then be removed in an impact mill, as already explained with reference to Figure 3.This can then be transferred via line 104 to a transport container 105 and then fed to wet-chemical processing. The lighter plastic particles can be fed to another cyclone 107 via a blower 106, and the particles separated there can be collected in a container 108. The exhaust gas from the two cyclones 102, 107 can be discharged via line 109 and fed, for example, to a cleaning device such as a scrubber or the like.

[0098] The medium-coarse fraction 20 separated in the separation process according to Figure 6, with particles of more than 500 pm up to a size of approximately 2 to 3 mm, which predominantly contains copper, aluminum, iron, plastics, and adhering black mass, is further treated in the process according to Figure 9, which is explained in more detail below. Via the feed line 110, this material reaches a vacuum dryer 111, where it is dried. The obtained dry black mass fraction 49 can be fed from the vacuum dryer 111 via line 112 to a barrel 113, where it is collected. From there, this black mass fraction 49 can be added via the outlet line 114 to the black mass fractions obtained in the other separation processes and subjected to wet-chemical processing, as already described with reference to Figure 5.The steam separated in the vacuum dryer 111 can be fed to a condenser 116 via line 115, where it can be condensed and then collected in the condensate tank 117. Industrial cooling water can be used to cool the steam, which is fed to the condenser 116 via line 118.

[0099] Reference symbol

[0100] 1 Preliminary proceedings

[0101] 2 batteries / battery cells / battery modules

[0102] 3 Identification step

[0103] 4 Discharge step

[0104] 5 Energy

[0105] 6 Disassembly

[0106] 7 Components of the battery

[0107] 8 Separation and / or sorting step

[0108] 9 sorted residues

[0109] 10 isolated batteries / battery cells / battery modules

[0110] 11 first sub-process / separation process

[0111] 12 Water

[0112] 13 Crushing process

[0113] 14 Separation step

[0114] 15 first aqueous graphite-enriched fraction

[0115] 16 second non-aqueous graphite-depleted fraction

[0116] 17 Drying step

[0117] 18 dried graphite-containing fraction / black-mass-containing fraction

[0118] 19 first aqueous graphite-enriched and particulate-free fraction

[0119] 20 non-aqueous graphite-depleted and particulate-laden fraction

[0120] 21 Sieving step

[0121] 22 Sieving step

[0122] 23 Pressing step

[0123] 24 contaminated water

[0124] 25 Water treatment step / water cycle

[0125] 26 second sub-process / separation process

[0126] 27 Separation step / separation device

[0127] 28 light fraction

[0128] 29 heavy fraction 30 suction step

[0129] 31 first graphite-containing secondary fraction containing aerosol

[0130] 32 Separation step / filter system

[0131] 33 first graphite-containing side fraction (black-mass-containing fraction)

[0132] 34 Crushing device / impact mill

[0133] 35 Sieving process

[0134] 37 plastics

[0135] 38 Collect

[0136] 39 Circular economy

[0137] 40 Air separation table / magnetic separator

[0138] 41 Collect

[0139] 42 third sub-process

[0140] 43 Drying device / vacuum dryer

[0141] 44 Condensate water

[0142] 45 Crushing device / impact mill

[0143] 46 Sieving process

[0144] 47 other black-mass factions

[0145] 48 Separation step / screening and pressing

[0146] 49 dried black-mass fraction / second graphite-containing side fraction (black-mass-containing fraction)

[0147] 50 plastics

[0148] 51 Collect

[0149] 52 Air separation table / magnetic separator

[0150] 53 Suction step

[0151] 54 black-mass faction

[0152] 55 second graphite-containing secondary fraction containing aerosol

[0153] 56 Separation step / filter system

[0154] 57 fourth sub-process

[0155] 58 Solvents

[0156] 59 Dissolve

[0157] 60 Sieving and / or filtering process

[0158] 61 Graphite 62 Collecting

[0159] 63 metallic solution

[0160] 64 pH adjustment

[0161] 65 Extract

[0162] 66 metallic sulfates

[0163] 67 Collect

[0164] 68 raw materials

[0165] 69 Ammonium sulfate

[0166] 70 Recycling

[0167] 71 Appendix

[0168] 72 Conveyor system / conveyor belt

[0169] 73 shredding device / shredder

[0170] 74 Line

[0171] 75 Input end

[0172] 76 Separator / Friction washer

[0173] 77 Exit end

[0174] 78 Line for the first aqueous graphite-enriched fraction

[0175] 79 Buffer tank

[0176] 80 Line for the second non-aqueous graphite-depleted fraction

[0177] 81 Silo

[0178] 82 Pump

[0179] 83 Separator / Sieve

[0180] 84 Line for the non-aqueous graphite-depleted and particulate fraction

[0181] 85 screw conveyors

[0182] 86 tanks

[0183] 87 Pump

[0184] 88 Line for the first aqueous graphite-enriched and particulate-free fraction

[0185] 89 Circulation tank

[0186] 90 line

[0187] 91 Filter press 92 Line

[0188] 93 Line

[0189] 94 Line

[0190] 95 Pump

[0191] 96 heat exchangers

[0192] 97 Return line

[0193] 98 Line

[0194] 99 Line for the dried graphite-containing fraction

[0195] 100 barrels

[0196] 101 Line

[0197] 102 Cyclone

[0198] 103 Separator / Zigzag separator

[0199] 104 Line, heavy fraction

[0200] 105 T ransport containers

[0201] 106 blowers

[0202] 107 Cyclone

[0203] 108 containers

[0204] 109 Exhaust pipe

[0205] 110 Feed line for the non-aqueous graphite-depleted and particulate fraction

[0206] 111 Vacuum dryer

[0207] 112 Line

[0208] 113 barrels

[0209] 114 Output line for black mass

[0210] 115 Line to the capacitor

[0211] 116 Capacitor

[0212] 117 Condensate tank

[0213] 118 Cooling water line

Claims

Patent claims 1. A process for obtaining graphite, and optionally valuable metals, preferably selected from at least one of the metals of the first and / or third main group and / or at least one of the metals of the 7th to 11th subgroups, from lithium-ion batteries; wherein the batteries (2, 10) having a residual charge of at most 30% are comminuted in a comminution device (73) with the addition of water (12), so that a mixture of comminuted batteries and water is obtained; wherein the mixture comprising the comminuted batteries and the water is separated into a first aqueous graphite-enriched fraction (15), which optionally also contains metal oxides, and a second non-aqueous graphite-depleted fraction (16); wherein the first aqueous graphite-enriched fraction (15) is then freed from water, so that a dried graphite-containing fraction (18), which optionally also contains metal oxides, is obtained.also contains metal oxides; and wherein the second non-aqueous graphite-depleted fraction (16) is passed through a separation device, in particular a zigzag separator (103), and is separated into a heavy fraction (29) containing particulate components with a bulk density of at least 0.02 kg / m³. 3 and in a light fraction (28) containing particulate components with a bulk density of at most 0.40 kg / m³ 3 is separated.

2. Method according to claim 1, wherein the heavy fraction (29) comprising a graphite-containing secondary fraction (33) is first crushed and then separated into pure fractions.

3. The method of claim 2, wherein the separation into the pure fractions is carried out by means of a sieve cascade which is configured to separate the crushed heavy fraction into a first medium fraction with metal-containing particles with a size on the order of about 250 pm to about 100 pm, a coarser fraction with plastic-containing particles with a size on the order of more than 250 pm and a third finer fraction with graphite-containing particles with a size on the order of less than 100 pm.

4. Method according to claim 3, wherein the middle fraction is subsequently separated into pure metallic fractions, optionally by means of an air separation table and / or a magnetic separator.

5. Method according to one of the preceding claims, wherein the aerosol (31) generated during the separation process and / or the comminution process and containing a part of the graphite-containing by-fraction is extracted and the part of the graphite-containing by-fraction (33) contained therein is separated, in particular filtered out.

6. Method according to one of the preceding claims, wherein the water (12) is added in a quantity of 20 to 200 m³ based on a quantity of 1000 kg of batteries (2, 10) per hour. 3 / h is supplied.

7. Method according to one of the preceding claims, wherein the water (12) is supplied at a temperature below room temperature, preferably at a temperature in the range of 5 °C to 20 °C.

8. Method according to one of the preceding claims, wherein the comminution within the comminution device (73) takes place in at least two stages, such that the batteries (2, 10) are first coarsely comminuted in a first stage and then finely comminuted in a subsequent second stage.

9. Method according to one of the preceding claims, wherein the water is collected, then cooled via a heat exchanger (96) and subsequently returned to the comminution device (73) and / or to the mixture comprising the comminuted batteries and the water.

10. Plant (71) for the recovery of graphite, and optionally of valuable metals, preferably selected from at least one of the metals of the first and / or third main group and / or at least one of the metals of the 7th to 11th subgroups, from lithium-ion batteries, comprising at least one comminution device (73) having a comminution unit that can be rinsed with an aqueous medium; at least one separation device (76) downstream of the comminution device (73) in the transport path, which preferably comprises at least one sieve, suitable for separating material obtained in the comminution device (73) into at least two to separate fractions (15, 16) of different particle sizes; at least one drying device, preferably a filter press (91), downstream of the separation device (76) in the transport path, for drying the fraction separated in the first separation device (76); and at least one further separation device (27, 103) by means of which lighter and heavier particles are separated from each other by an airflow, wherein this further separation device (27, 103) is downstream of the separation device (76) in the transport path. System (71) according to claim 10, further comprising a further comminution device, in particular an impact mill (34), downstream of the at least one separation device (76) in the transport path, which serves to further reduce the particle size of the previously separated fraction (29). System (71) according to claim 10 or 11, wherein the comminution unit comprises at least two comminution stages arranged one below the other following gravity.

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