Filter device and reaction vessel and method for producing aqueous slurry using the same

Abstract

A filter device (100, 200, 300) is disclosed, comprising a conduit (10) having an inlet (30) and an outlet (20). The filter device also comprises a filter module (90), comprising a tubular filter (40) having a first end (40a) and a second end (40b), the first end (40a) being open and the second end (40b) being sealed. The filter module (90) comprises a suction tube (60) positioned to extend inside the tubular filter (40) between the first end (40a) and the second end (40b). The extension of the suction tube (60) inside the tubular filter (40) is such that there is an intermediate space (80) between the tubular filter (40) and the suction tube (60) that is fluidly connected to the inlet (30) of the conduit (10) via the suction tube (60). A reaction vessel and method for producing an aqueous slurry are also disclosed.

Description

Technical Field

[0001] Generally, the present invention relates to a filter device, a reaction vessel, and a method for producing an aqueous slurry using the same. In particular, the present invention relates to a filter device for a reaction vessel suitable for solid-liquid separation, although not exclusively.

Background Art

[0002] In a lithium-ion secondary battery, a lithium transition metal oxide as a cathode active material is generally produced from a precursor material of a transition metal hydroxide, or an oxidized form thereof, or a transition metal carbonate, and then by a coprecipitation process. Such a precipitation process generally involves mixing a liquid reactant of a metal salt solution and an aqueous solution of a precipitant in the presence of a potential complexing agent.

[0003] These precursor synthesis reactions are maintained for several hours to several tens of hours depending on the size and growth rate of the precipitated particles obtained during the process. Therefore, in the case of a batch precipitation process, when the volume of the raw materials supplied to the reactor, that is, the reactants, exceeds the limit of the reactor, solid-liquid separation, that is, removal of a partial liquid portion by filtration, that is, partial mother liquor removal, can be carried out to continue the precipitation.

[0004] Generally used mother liquor removal methods include an external concentrator in which solid-liquid separation is carried out outside the reactor and then the separated solid is circulated back to the reactor. This causes problems that change the quality, such as the particle size between the synthesized precursors, because the particles involved in the solid-liquid separation outside the reactor are not involved in the precipitation synthesis inside the reactor. In addition, the external concentrator also does not allow synthesis of, for example, either a gradient-like metal content of the precursor particles or a core-shell structure.

[0005] In view of the above, there is a need for further improvement of solid-liquid separation devices and methods in order to improve the physical quality and other properties of the precursor material.

Summary of the Invention

[0006] Therefore, an object of the present invention is to provide a reaction vessel suitable for solid-liquid separation, i.e., a filter device for a reaction container, without removing the solid fraction from the reaction vessel during the production of an aqueous slurry.

[0007] A further object of the present invention is to provide a reaction vessel equipped with a filter device.

[0008] A further object of the present invention is to provide a method for producing an aqueous slurry in which solid-liquid separation is carried out by using a filter device. [Means for solving the problem]

[0009] In a first aspect, the object of the present invention is solved by providing a filter device as described in claim 1. The filter device comprises a conduit having an inlet and an outlet for guiding a filtrate, i.e., the liquid to be filtered, to the outside of a reaction vessel. In other words, the conduit is arranged to direct / pass the filtrate from its inlet to its outlet. The filter device also comprises a filter module comprising a tubular filter having a first end and a second end. The first end of the tubular filter is open, and the second end of the tubular filter is sealed, i.e., closed. The filter module comprises a suction tube positioned between the first and second ends of the tubular filter, extending inward from the tubular filter. The suction tube is positioned to extend inward from the tubular filter such that there is an intermediate space between the tubular filter and the suction tube. Furthermore, the suction tube is positioned to connect to the inlet of the conduit such that the intermediate space is fluidly connected to the inlet of the conduit via the suction tube.

[0010] The intermediate space is understood as the internal space of the filter module formed between the inner wall of the tubular filter and the outer wall of the suction tube. Advantageously, the intermediate space is an otherwise closed, i.e., sealed, internal space, but includes an opening on the side of the second end of the tubular filter. The opening is positioned to provide a fluid connection to the inside of the suction tube. In other words, the suction tube is positioned to provide a separate fluid connection between the intermediate space and the inlet of the conduit, so that when the liquid / solution is filtered through the tubular filter, the filtered liquid / solution, i.e., the filtrate, passes into the suction tube and then into the inside of the conduit. Advantageously, the opening is positioned close to the second end of the tubular filter.

[0011] One of the advantages achievable with a suction tube is that, when the filter device is in use, there is no liquid pillar inside the intermediate space, and all the filtrate from there is arranged to pass through to the end of the suction tube, i.e., the head, toward the second end of the tubular filter, thereby maximizing the effective filtration area of ​​the tubular filter.

[0012] When the filter device is used for solid-liquid separation, the tubular filter of the filter module is oriented so as to be at least partially located inside the reaction vessel, and the outlet of the conduit is connected to a suction pump, such as a gas suction pump (e.g., a liquid ring vacuum pump, a root pump, etc.), which is oriented to create a vacuum inside the filter device. Thus, when the filter device is used for solid-liquid separation, there is a vacuum inside the conduit, and the filter module is connected there via a connection between the inlet of the conduit and the suction tube. If the filter module is at least partially below the liquid level inside the reactor, the liquid inside the reactor may pass through the tubular filter inside the intermediate space of the filter module due to the vacuum. Thereafter, inside the intermediate space, the filtrate passes through the suction tube via its end toward the second end of the tubular filter. The filtrate inside the suction tube is then directed toward the inlet of the conduit and further toward the outside of the filter device via the outlet of the conduit.

[0013] Therefore, the filter device according to the present invention offers several advantages compared to existing external concentrators when used for solid-liquid separation in a precipitation process. For example, it allows for a narrower particle size distribution of the precipitated particles. Furthermore, it enables the synthesis of a gradient-like metal content and core-shell structure in the precursor particles. Thus, the physical quality and other properties of the precursor material can be better improved and / or controlled.

[0014] Advantageously, the filter module is designed so that the suction tube extends close to the second end of the tubular filter. This allows for maximizing the effective filtration area of ​​the tubular filter, i.e., the area actually available for particle filtration.

[0015] One advantage of the filter device is that it can be installed / mounted on top of the reaction vessel, such as on the lid of the vessel. Advantageously, this mounting, i.e., the joint between the filter device and the reaction vessel, is made to be airtight. When the filter device is mounted on top of the reaction vessel, it is assumed that the filter module is at least partially inside the reaction vessel. Advantageously, the tubular filter is inserted so that its effective filtration area is all below the desired liquid level.

[0016] In some embodiments, the tubular filter includes a flat sheet membrane filter, such as a woven fabric, which is arranged into a tubular shape by, for example, sewing, gluing, or welding. The flat sheet membrane filter is advantageously a multifilament woven fabric made of a polymer material such as polyester and / or polypropylene. If the tubular filter includes a woven fabric as the filtration medium, the tubular filter may further comprise a support frame on which the woven fabric is supported to ensure that the tubular shape is maintained.

[0017] In some embodiments, the tubular filter is positioned at least partially in alignment with a portion of the suction tube that extends between a first end and a second end of the tubular filter.

[0018] Advantageously, the joint between the conduit and the filter module is airtight. In some embodiments, both the inlet end of the conduit, i.e., the head, and the end of the suction tube intended to be joined to the inlet, are arranged to screw together to fit. For example, when the threads are screwed together, a sealed connection can be provided between the suction tube and the conduit. Configured in this way, the filtrate inside the suction tube can enter the inlet of the conduit, pass sequentially through the conduit, and exit the conduit through the outlet. Additionally or alternatively, the inlet head of the conduit may have a female mating portion, the seal of which engages with the filter module a Luer mating portion or similar to provide the sealed connection. The advantage of the airtight joint between the conduit and the filter module is that the vacuum inside the intermediate space is maximized, and therefore the filtration performance of the filter device is maximized.

[0019] According to one embodiment, the end of the intermediate space toward the conduit is sealed. For example, the end may be sealed by a hollow cap positioned to fit outside the conduit inlet and outside the tubular filter. Additionally or alternatively, the filter module may include a sealing member positioned to seal the first end of the tubular filter from the side and to extend inside the intermediate space to bond with the outside of the suction tube and / or a portion of the conduit inlet outside the tubular filter.

[0020] A tubular filter has a filter medium, i.e., a filtration medium, filtrate medium, etc., which contains a plurality of pores, preferably sub-micrometer and / or micrometer-sized pores, suitable for solid-liquid filtration through the tubular filter. Advantageously, in some embodiments, the filtration medium of the tubular filter is suitable for solid-liquid filtration and allows only particles having a particle size of 0.5 μm or less, preferably 0.3 μm or less, to pass through the filtration medium. In other words, a tubular filter has porosity characteristics that can be designed according to what size of solid material is intended to be avoided passing through the tubular filter during solid-liquid filtration.

[0021] In characterizing the porosity of a filtration membrane or filtration medium, for example, from the viewpoints of total porosity %, total pore area, and median pore diameter, mercury intrusion porosimetry measurement method(s) can be used.

[0022] The tubular filter can include a porous membrane. Additionally or alternatively, the tubular filter can be a tubular filtration membrane.

[0023] According to one embodiment, the tubular filter includes a membrane made of a polymer material, preferably a thermoplastic polymer, and preferably the polymer material includes polyamide, polyethylene, and polytetrafluoroethylene, or any combination thereof.

[0024] In some embodiments, the filtration medium is made of high-density polyethylene (HDPE).

[0025] According to one embodiment, the tubular filter includes a membrane made of ceramic, and preferably the ceramic is made of an inorganic material including alumina, titania, zirconium oxide, and silicon carbide, or any mixture thereof.

[0026] The pores of the tubular filter, such as the pores of the membrane of the tubular filter, can be made, for example, by thermal sintering of particles of the filtration medium or the membrane. Since the tubular filter, especially the tubular filtration membrane itself, is known, those skilled in the art can provide a tubular filter suitable for the application to which the filter device is applied. Alternatively, the filtration medium can consist of a flat sheet membrane filter as described above.

[0027] According to one embodiment, the tubular filter has a nominal pore diameter in the range of approximately 0.1 μm to approximately 20.0 μm, preferably in the range of approximately 0.2 μm to approximately 20.0 μm, more preferably in the range of approximately 0.3 μm to approximately 15.0 μm. As understood by those skilled in the art, the nominal pore diameter depends on the application of the filter device. For example, determining what kind of porosity characteristics, such as the pore diameter of the filtration medium used, depends on the particle diameter of the solid designed to be filtered.

[0028] In the characterization of the porosity of the filtration membrane, in the present disclosure, the term "nominal pore size" refers to the diameter of the smallest particles that cannot pass through the membrane. Porosimetry is generally used to determine the nominal pore size. The first bubble point (FBP), as defined by ASTM F-316-03 (2011) "Standard Test Methods for Pore Size Characteristics of Membrane Filters by Bubble Point and Mean Flow Pore Test", is generally used to characterize the nominal pore size of the filtration membrane.

[0029] According to one embodiment, the suction tube comprises a tubular wall that is impermeable to the filtrate, i.e., the liquid to be filtered. This has the advantage that there is no liquid pillar inside the intermediate space and all the filtrate from there passes through the end of the suction tube, i.e., the head, towards the second end of the tubular filter, i.e., the effective filtration area can be maximized. The suction tube can be made of, for example, stainless steel.

[0030] According to one embodiment, the filter device comprises a plurality of filter modules installed spaced apart from each other, and the intermediate space of each of the plurality of filter modules is fluid-connected to the inlet of the conduit.

[0031] The plurality of filter modules may be arranged side by side, or in a circular pattern, or both, forming a bundle configuration that allows increasing the total effective filtration area and thus the performance of the filter device.

[0032] Multiple filter modules can be configured to receive the filtrate from multiple filter modules using a single inlet of a conduit. For example, multiple tubular filters may be arranged in a connected belt-like configuration, connected to a single suction tube that branches to these multiple tubular filters. Alternatively, multiple tubular filters may each have a separate suction tube connected to a separate inlet of a conduit.

[0033] According to one embodiment, the filter device comprises a plurality of filter modules, the conduit comprises a plurality of inlets, and each intermediate space of the plurality of filter modules is fluidly connected to one inlet.

[0034] According to one embodiment, the filter device comprises a stem, the stem being positioned such that its proximal end is fixed to a conduit and its distal end is fixed to a support member. The stem is positioned to support a plurality of filter modules in the conduit of the device. In this embodiment, the second ends of the tubular filters of the plurality of filter modules are supported by the support member from the side of the support member facing the conduit. Preferably, the stem is positioned at least partially aligned with the plurality of filter modules.

[0035] According to one embodiment, the second end of the tubular filter of each filter module is placed within each support element of the support member. Preferably, an elastic element, such as a spring or similar, is positioned between the second end of the tubular filter and the support member. The elastic element is oriented to accommodate possible variations in the length of the filter modules supported by the same support member.

[0036] According to one embodiment, a plurality of filter modules are arranged in a circular pattern. Preferably, the stems are positioned inside the circular pattern. The effect of the circular pattern is that it can optimize the required effective filtration area and space in the lateral direction, when the tubular / longitudinal axis of the filter module is perpendicular. In other words, the filter modules are then positioned to be effectively rinsed inside the reactor during the precipitation process. Such a pattern of filter modules also advantageously forms a baffle inside the reactor when installed in addition to, or instead of, the reactor's original baffle(s).

[0037] When a filter device is used and it is difficult to maintain uniform filter performance due to contamination and / or partial clogging of the tubular filter, it is preferable to restore / control performance by performing a purging process by reverse pulse or back blow to the filter module, i.e., by generating a positive pulse-type pressure inside the filter module.

[0038] According to one embodiment, the conduit includes a gas inlet arranged to enable the purging process.

[0039] According to one embodiment, the conduit has an internal space, and the inlet and outlet of the conduit are fluidly connected through the internal space of the conduit, with the inlet of the conduit extending higher into the internal space than the outlet of the conduit when viewed from the side such that the second end of at least one tubular filter faces downward. The advantage is that backflow of filtrate into the tubular filter is avoided.

[0040] In a second aspect, the object of the present invention is solved by providing a reaction vessel suitable for precipitation of hydroxides or oxyhydroxides of one or more metal elements, the reaction vessel comprising a filter device according to the first aspect of the present invention.

[0041] According to one embodiment, the reaction vessel includes an external filtrate storage tank, which is fluidly connected to the outlet of a filter device, for storing the filtrate separated through the filter device.

[0042] In a third aspect, the object of the present invention is solved by providing a method for producing an aqueous slurry. The method comprises supplying and mixing a first aqueous solution containing a metal salt, preferably one or more elements, including at least one of Ni, Co, and Mn, and a second aqueous solution containing a precipitant, into a reaction vessel, thereby forming an aqueous slurry containing a liquid fraction, i.e., mother liquor, and a solid fraction, i.e., precipitate. When a predetermined liquid level is reached inside the reaction vessel, the method further comprises increasing the solid fraction of the aqueous slurry by vacuum filtering the aqueous slurry inside the reaction vessel through a filter device according to the first aspect.

[0043] According to one embodiment, the precipitant comprises at least one selected from hydroxides, carbonates, and bicarbonates. The hydroxide may be an alkali metal hydroxide such as NaOH. The carbonate may be, for example, ammonium carbonate or potassium bicarbonate, and the bicarbonate may be, for example, sodium bicarbonate.

[0044] According to one embodiment, the method further comprises supplying and mixing a third aqueous solution containing a complexing agent into a reaction vessel. Preferably, the complexing agent is selected from ammonia, glycine, tartrate, citrate, and oxalate. Preferably, the complexing agent is ammonia.

[0045] Various embodiments of the present invention are disclosed in the claims and herein. The embodiments and examples enumerated in the claims and specification can be freely combined with each other unless otherwise expressly stated. Throughout this specification, where any numerical range is provided, the range also includes endpoint values ​​unless otherwise expressly stated.

[0046] Embodiments of the present invention will be described in more detail below with reference to the drawings. Thereafter, the same reference numerals refer to the same or corresponding elements, avoiding unnecessary re-description of them. [Brief explanation of the drawing]

[0047] [Figure 1A] Figure 1A shows a first advantageous design 100 of the filter device. [Figure 1B] Figure 1B shows a first advantageous design 100 of the filter device. [Figure 2A] Figure 2A shows a second advantageous design 200 for the filter device. [Figure 2B] Figure 2B shows a second advantageous design 200 for the filter device. [Figure 3A] Figure 3A shows a third advantageous design 300 for the filter device. [Figure 3B] Figure 3B shows a third advantageous design 300 for the filter device. [Figure 4] Figure 4 shows an advantageous design of the filter module pattern 400. [Figure 5] Figure 5 shows an advantageous design 500 for the filter module. [Figure 6] Figure 6 shows another advantageous design 600 for the filter module. [Figure 7] Figure 7 shows SEM images of two examples of the filtration medium, 701 and 702. [Figure 8] Figure 8 shows an advantageous design for the reaction vessel 800. [Modes for carrying out the invention]

[0048] Detailed description of the invention The following detailed description will elaborate on preferred embodiments to enable the implementation of the present invention. While the present invention is described with reference to these specific preferred embodiments, it will be understood that the present invention is not limited to these preferred embodiments. Conversely, the present invention includes numerous alternatives, variations, and equivalents, which will become apparent from the following detailed description and accompanying drawings.

[0049] As used herein and in the claims, the term “comprising” should not be construed as limiting to the means listed thereafter, nor as excluding other elements or steps. It should be construed as specifying the presence of the described features, integers, steps, or components mentioned, but not as precluding the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Accordingly, the expression “composition comprising components A and B” should not be limited to a composition consisting solely of components A and B. This means that, with respect to the present invention, components A and B are merely relevant in the composition. Thus, the terms “comprising” and “including” encompass the more restrictive terms “consisting essentially of” and “consisting of.”

[0050] Referring in detail to the figures, Figures 1A and 1B show a first advantageous design 100 of the filter device. Figure 1A is a side view, and 1B is a side cross-sectional view of the 100, respectively. The filter device has a conduit 10, a filter module 90, and a hollow connector 12. In this embodiment, the conduit 10 is a hollow tube with one end being an inlet 30 and the other end being an outlet 20. The inlet 10, which is oriented vertically in the figure, is fitted to the filter module 90 and the hollow connector 12. The inlet 10 forms a connection with the end of the suction tube 60 of the filter module 90, i.e., the inlet is fitted to receive filtrate from the suction tube 60. The filter module 90 also includes a tubular filter 40 having a filtration medium. The tubular filter 40 surrounds the suction tube 60 such that there is an intermediate space 80 between the inner wall of the tubular filter 40 and the outer wall of the suction tube 60. The suction tube 60 extends inside the tubular filter 40 between the first end 40a and the second end 40b of the tubular filter 40. The intermediate space 80 continues along the side of the second end 40b of the tubular filter 40 so that the filtrate inside the intermediate space 80 can pass through the open end of the suction tube 60 facing the second end 40b, i.e., the end of the suction tube 60 facing downward in the figure. In other words, the intermediate space 80 is fluidly connected to the inlet 30 via the suction tube 60. In this embodiment, the hollow connector 12 seals the end of the intermediate space 80 on the first side 40a of the tubular filter 40.

[0051] The hollow connector 12 is not essential to the present invention. The presence or absence of the hollow connector 12 depends on the material used. For example, the tubular filter may be designed so that the first end 40a of the tubular filter is welded, bonded, etc. to the suction tube so that the intermediate space 80 is sealed at its end.

[0052] The hollow connector 12 may have threads or a collar, or both, on its outside, adapted to provide a means for attaching the filter device to the reaction vessel, as shown in design 100 of the figure.

[0053] When the filter device is used for solid-liquid separation, the tubular filter 40 of the filter module 90 is oriented to be at least partially located inside the reaction vessel, as shown in Figure 7 for the design described below, and the outlet 20 of the conduit 10 is connected to a suction pump or similar device oriented to create a vacuum inside the filter device.

[0054] The filter device is advantageously mounted on top of the reaction vessel such that at least a portion of the filter medium of the tubular filter 40 is positioned below the determined / desired liquid level inside the reaction vessel. To obtain good filtration performance for the filter device in use, the filter medium of the tubular filter is positioned entirely below the liquid level. This allows the liquid / solution to be drawn through the tubular filter 40, but prevents gas from being drawn into the intermediate space 80 from the potential gas / atmosphere space, i.e., the space between the reaction vessel lid and the liquid surface inside the reaction vessel.

[0055] Figures 2A and 2B show a second advantageous design 200 of the filter device. This 200 differs from design 100 in that the conduit 10 comprises a container having an inner space 25. This inner space 90 is formed by the outer wall 10a of the conduit and the flange 50. As shown in the figure, when design 200 is viewed from the side, the inlet 30 of the conduit 10 extends higher than the outlet 20 of the conduit 10 due to the inner space 25. This prevents backflow of the filtrate into the tubular filter.

[0056] The inlet 30 and outlet 20 are fluidly connected via the inner space 25 of the conduit 10. When a filter is used and the outlet 20 is connected to a vacuum pump, the filtrate enters the inner space 25 through the inlet 10 and exits the inner space 20.

[0057] In design 200, the flange 50 has both an external and an internal component. The internal portion of the flange closes the internal space 25 together with the external wall 10a. In some embodiments, the flange 50 may include either an external component or an internal component, or both.

[0058] The filter device design 200 further comprises a frame 10b below the inner space 25, which is formed by the outer wall 10b and flange 50. Advantageously, this frame 10b fits into the end of the inlet 30, which is coupled with the suction pipe 60.

[0059] The external portion of the flange 50 may be used as a mounting means for attaching the filter device 200 to the reaction vessel. In this case, as shown in the figure below, the flange 50 filter device is positioned inside the reaction vessel. Advantageously, the frame may be sized such that when the filter device is in use, the end of the frame 10b toward the second end of the tubular filter 80 is within a predetermined liquid level area of ​​the reaction vessel.

[0060] Advantageously, the inner space 25 is a pressure vessel. The design 200 includes a gas inlet 60, which is positioned to allow back-blow of, for example, N2 gas inside the filter device to remove contaminants from the tubular filter.

[0061] The gas inlet 60 is equipped with a valve 61 to enable the back blow. During the back blow, advantageously, a filtrate discharge line connected to the outlet between the vacuum pump or similar is closed to fully direct the blow gas to the filter module 90.

[0062] Figures 3A and 3B show a third advantageous design 300 of the filter device. This 300 differs from design 200 in that it comprises multiple filter modules 90.

[0063] In design 300, the filter modules 90 are installed spaced apart from each other. Each intermediate space 80 of the multiple filter modules 90 is fluidly connected to a single inlet 10.

[0064] In some embodiments, multiple filter modules 90 are connected to the same inlet 10, which are not shown in the figure.

[0065] Multiple filter modules may be arranged side by side, in a circular pattern, or both, forming a bundle configuration that allows for an increase in the total effective filtration area and, consequently, the performance of the filter device.

[0066] In design 300, the filter device further comprises a stem 95 fixed between the conduit 10 and a support member 85 for supporting the filter module 90. The proximal end 95a of the stem 95 is fixed to the bottom of the conduit 10, facing toward the second end 40b of the tubular filter 40. The distal end 95b of the stem 95 is fixed to the support member 85 on the side of the support member 85 facing toward the conduit. In this design 300, the second end 40b, the tubular filter 40, is thereby supported by the support member 85 from the side of the support member 85 facing toward the conduit 10. The stem 95 aligns with the filter module.

[0067] In the design of the filter device 300, the second end 40b of the tubular filter 40 of each filter module 90 is placed on each support element 86 of the support member 85. In some embodiments, the support member 85 includes an elastic element positioned between the second end 40b of the tubular filter and the support member 85. The elastic element is not shown in the figure. The elastic element is oriented to accommodate possible length variations of the filter modules supported on the same support member.

[0068] In some embodiments, multiple filter modules are arranged in a circular pattern. Preferably, the stems are positioned inside the circular pattern. Such an advantageous design of the filter module 400 is shown in Figure 4. The figure shows a bottom view of 16 tubular filters in the filter module.

[0069] Several possibilities for joining the conduit 10 to the filter module 90 are disclosed herein. Figure 5 shows one such possibility, where in design 500 there is a hollow connector 12 that is tuned and extends both inside the intermediate space and outside the tubular filter 40 on its first side 40b. Another end of the hollow connector 12 is tuned and aligned with the end of a suction tube 60 joined together with the inlet 30 of the conduit, the inlet not shown in the figure. A nipple 66 may be inserted between the suction tube 60 and the inlet 30, the nipple 66 is shown in the figure. Depending on the embodiment, the nipple 66 may or may not include threading.

[0070] Figure 6 shows another possibility for joining the conduit 10 to the filter module 90. In this design 600, a portion of the suction tube 60, located outside the first end 40a of the tubular filter 40, has threads that engage with the respective threads in the head of the conduit inlet 30, and the joining is not shown in the figure. Furthermore, design 600 includes a sealing member 22 fitted to the first side 40a of the tubular filter 40 to seal the end of the intermediate space 80. Advantageously, the sealing member 22 extends into the intermediate space 80 to reinforce and / or secure the seal of the intermediate space 80.

[0071] In addition to the sealing member 22, as shown in the figure, a sleeve 24 may be provided on the outer wall of the tubular filter 40, on its first side 40a, to further secure the sealing member. Additionally or alternatively, the sleeve 24 may be used to close / seal the holes of the tubular filter 40 on its first side 40a.

[0072] Suitable materials for a portion of the tubular filter 40 that provides a filtration medium, such as a filtration membrane, may include polymer materials. Preferably, the polymer material is a thermoplastic polymer, such as polyamide, polyethylene, and polytetrafluoroethylene, or any mixture thereof. A suitable example of such polymer is polyethylene. The membrane may be manufactured, for example, by thermal sintering. Alternatively or additionally, the membrane may include ceramics. Preferably, the ceramics are made from inorganic materials, such as alumina, titania, zirconia oxide, and silicon carbide, or any mixture thereof.

[0073] Figure 7 shows a schematic diagram of the tubular filter 40. The upper left corner of the figure shows a scanning electron microscope (SEM) image of Example 701 of the filtration medium for the tubular filter 40. The lower left corner of the figure shows an SEM image of another Example 702 of the filtration medium for the tubular filter 40. Both Examples 701 and 702 were fabricated by thermal sintering HDPE particles. Both 701 and 702 were tested and found to be suitable for filtration in filter devices used in the manufacturing processes of aqueous slurries as described above and below in this specification.

[0074] The porosity properties of Examples 701 and 702 were studied by performing mercury intrusion measurements on the samples of 701 and 702. Table 1 below summarizes the obtained porosity properties of 701 and 702. Mercury intrusion measurements were performed using an Anton Paar PoreMaster 60-GT instrument, according to the manufacturer's instructions, under the following conditions: the sample cell was 1.5 inches, the intrusion pressure range was 0.721 PSIA to 50.063 PSIA, and the extrusion pressure range was 49.436 PSIA to 0.724 PSIA. [Table 1]

[0075] The wall thickness of a portion of the tubular filter 40 that provides a filtration medium such as a membrane can vary depending on the application. This can be, for example, in the range of approximately 0.5 mm to 20 mm.

[0076] There are various suitable materials for conduits and suction tubes. As mentioned above, suction tubes are advantageously made of materials that are impermeable to air and other gases, as well as to liquids such as the liquid being filtered. For example, stainless steel can be used.

[0077] The dimensions of the filter device, particularly the dimensions of the tubular filters of the filter unit(s), which affect filtration performance such as the effective filtration area, depend on the properties of the filter medium used, e.g., its porosity, and the application in which the filter device is used. However, advantageously, the filtration performance, i.e., the amount that can be filtered through the filter device, is at least approximately equal to a given rate of solution supply to the reactor. This can be achieved, for example, by changing the filter module 90 and the number of components therein, and by changing their dimensions, including their cross-sectional and length dimensions, and / or by changing the properties of the filter medium of the tubular filters(s). This can be easily done by those skilled in the art within the scope of the appended claims.

[0078] Several advantages of providing a filtering device are described above. Individual means can be advantageously combined with one another.

[0079] Figure 8 shows one possible design 800 of another aspect of the present invention, which is a reaction vessel suitable for precipitating hydroxides or oxyhydroxides of one or more metal elements, and the reaction vessel is equipped with a filter device according to the first aspect of the present invention.

[0080] Design 800 comprises a filter device 300 as described above, mounted on top of the reactor vessel 76. Furthermore, it comprises a filtrate discharge line 78 connected to the outlet 20 of the filter device for discharging the filtrate, i.e., the fluid filtered through the device 300. Moreover, it comprises a raw material supply line 72 arranged to supply raw materials, such as a mixture of metal solutions, into the reactor vessel 76, and a mixer 74 arranged to mix the raw materials supplied to the reactor vessel 76. The filtrate discharge line 78 may also comprise a vacuum pump or similar, not shown in the figure, for generating a vacuum inside the filter device as described above.

[0081] To avoid or reduce contamination and / or blockage of the tubular filter of the filter apparatus, the raw material supply line 72 and the filter apparatus are advantageously positioned on the side facing the inside of the reactor, as shown in the figure.

[0082] The reaction vessel may include an external filtrate storage tank, not shown in the figure, which is fluid-connected to the outlet of the filter device for storing the filtrate.

[0083] In yet another aspect of the present invention, a method for producing an aqueous slurry is disclosed. The method comprises supplying and mixing raw materials, comprising a first aqueous solution containing a metal salt of one or more elements such as metal elements and a second aqueous solution containing a precipitant, in a desired mixture ratio, into a reaction vessel. The one or more metal elements include at least one of Ni, Co, and Mn. Depending on the application, when a predetermined liquid level is reached inside the reaction vessel, for example, a level that may be 80-100% of the internal volume of the reaction vessel, the method further comprises increasing the solid fraction of the aqueous slurry by vacuum filtering the aqueous slurry inside the reaction vessel through a filter device according to the first aspect of the present invention.

[0084] The solid fraction of the resulting aqueous slurry may contain either hydroxide or carbonate particles, depending on the precipitating agent used. Such particles can be used as precursor materials for lithium transition metal cathode materials for positive electrodes. The desired precursor material, for example, its desired chemical composition and size, can be obtained by washing and drying the product obtained according to the aqueous slurry manufacturing process.

[0085] For example, filtration may be performed such that there are predetermined lower and upper limits to the liquid level, when the filter device is positioned to maintain the liquid level between the limits.

[0086] The supply and mixing of raw materials in this method may further include the supply and mixing of a third aqueous solution containing a complexing agent into the reaction vessel. The complexing agent may be selected from ammonia, glycine, tartrate, citrate, and oxalate, or similar. The content of the complexing agent may be any suitable amount commonly used in the art for complexing agents. For example, the complexing agent is aqueous ammonia.

[0087] Advantageously, the liquid level inside the reaction vessel can be kept substantially constant by adjusting the volume of filtrate discharged from the filtering device and the volume of raw materials supplied to the reaction vessel to substantially the same value per unit of time.

[0088] The steps of supplying and mixing raw materials may be any of the following steps or a combination thereof: 1) an inert gas, e.g., N2 gas, and / or N e 1) providing a fully or partially inert gas atmosphere inside the reaction vessel by passing a mixture of gases, such as a mixture of gas and air; 2) providing an initiating solution to the reaction vessel, including providing an aqueous solution containing one or more precipitants and possible complexing agents; and 3) adjusting and maintaining a desired temperature inside the reaction vessel.

Claims

1. A filter device for a reaction vessel (100, 200, 300), wherein the filter device is A conduit (10) for guiding the filtrate to the outside of the reaction vessel, comprising an inlet (30) and an outlet (20), A filter module (90) comprising a tubular filter (40) having a first end (40a) and a second end (40b), wherein the first end (40a) of the tubular filter (40) is open and the second end (40b) of the tubular filter (40) is sealed, The filter module (90) comprises a suction tube (60) positioned between the first end (40a) and the second end (40b) of the tubular filter (40), extending inward from the tubular filter (40), with an intermediate space (80) between the tubular filter (40) and the suction tube (60), and the intermediate space (80) being fluidly connected to the inlet (30) of the conduit (10) via the suction tube (60), in the filter device (100, 200, 300).

2. The filter apparatus (100, 200, 300) according to claim 1, wherein the tubular filter (40) comprises a membrane made of a polymer material, preferably a thermoplastic polymer, and preferably the polymer material comprises polypropylene, polyamide, polyethylene, and polytetrafluoroethylene, or any mixture thereof.

3. The filter apparatus (100, 200, 300) according to claim 1, wherein the tubular filter (40) comprises a film made of ceramic, preferably the ceramic is made of an inorganic material comprising alumina, titania, zirconium oxide, and silicon carbide, or any mixture thereof.

4. The filter device (100, 200, 300) according to any one of claims 1 to 3, wherein the end of the intermediate space (80) toward the conduit (10) is sealed.

5. The filter apparatus (100, 200, 300) according to any one of claims 1 to 4, wherein the tubular filter is suitable for solid-liquid filtration of particles having a size of 0.5 μm or less, preferably 0.3 μm or less.

6. The filter device (100, 200) according to any one of claims 1 to 5, wherein the suction tube (60) has a tubular wall that is impermeable to the filtrate.

7. The filter device (300) according to any one of claims 1 to 6, wherein the filter device comprises a plurality of filter modules (90) installed apart from each other, and each intermediate space (80) of the plurality of filter modules (90) is fluidly connected to the inlet (30) of the conduit (10).

8. The filter device (300) according to claim 7, wherein the conduit (10) is provided with a plurality of inlets (30), and each intermediate space (80) of the plurality of filter modules (90) is fluidly connected to one inlet (30).

9. The filter device (300) according to claim 7 or 8, comprising a stem (95) such that the proximal end (95a) of the stem (95) is fixed to the conduit (10) and the distal end (95b) of the stem (90) is fixed to a support member (85), wherein the second end (40b) of the tubular filter (40) of the plurality of filter modules (90) is supported by the support member (85) from the side of the support member (85) facing the conduit (10), and preferably the stem (95) is arranged in alignment with the plurality of filter modules (90).

10. The filter device (300) according to claim 9, wherein the second end (40b) of the tubular filter (40) of each filter module (90) is installed within each support element (86) of the support member (85), and preferably an elastic element is disposed between the second end 40b of the tubular filter 40 and the support member (85).

11. The filter device (300) according to any one of claims 7 to 10, wherein the plurality of filter modules are arranged in a circular pattern, and preferably the stem is positioned inside the circular pattern.

12. The filter device (200, 300) according to any one of claims 1 to 11, wherein the conduit (10) comprises an inner space (25), the inlet (30) and the outlet (20) of the conduit (10) are fluidly connected via the inner space (25) of the conduit (10), and the inlet (30) of the conduit (10) extends higher into the inner space (25) than the outlet (20) of the conduit when viewed from the side with the second end (40b) of at least one tubular filter (40) facing downward.

13. The filter device (200, 300) according to any one of claims 1 to 12, wherein the conduit (10) is provided with a gas inlet (62).

14. A reaction vessel for precipitation, wherein the reaction vessel is equipped with a filter device (100, 200, 300) according to any one of claims 1 to 13.

15. The reaction vessel according to claim 14, wherein the reaction vessel comprises an external filtrate storage tank, which is fluidly connected to the outlet (20) of the filter device (100, 200, 300) for storing the filtrate separated through the filter device (100, 200, 300).

16. A method for producing an aqueous slurry, wherein the method is The method comprises supplying a first aqueous solution containing a metal salt of one or more elements, preferably the one or more elements containing at least one of Ni, Co, and Mn, and a second aqueous solution containing a precipitant into a reaction vessel and mixing them, thereby forming an aqueous slurry containing a liquid fraction and a solid fraction, wherein when a predetermined liquid level is reached inside the reaction vessel, the method is performed. A method further comprising increasing the solid fraction of the aqueous slurry by vacuum filtering the aqueous slurry inside the reaction vessel through a filter device (100, 200, 300) according to any one of claims 1 to 13.

17. The method according to claim 16, wherein the precipitating agent comprises a hydroxide or at least one selected from carbonates and bicarbonates.

18. The method according to claim 16 or 17, further comprising supplying and mixing a third aqueous solution containing a complexing agent into the reaction vessel, preferably the complexing agent being selected from ammonia, glycine, tartrate, citrate, and oxalate, and preferably the complexing agent being ammonia.

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