Cross-flow filtering device and nickel sulfate solution impurity removal and purification method and equipment

Abstract

The invention discloses a cross-flow filtering device and a nickel sulfate solution impurity removal and purification method and equipment, and mainly solves the technical problems that the whole cross-flow filtering system is large in occupied area and high in cost due to the fact that different cross-flow filters are arranged in series at present. Comprising a to-be-filtered liquid header pipe and a concentrated liquid header pipe which are connected in series through a circulating pump during working; the first group of cross-flow filtering components comprises at least two first cross-flow filtering components which are mounted on the filtrate header pipe in parallel, and the to-be-filtered liquid input ends of the first cross-flow filtering components are communicated with the filtrate header pipe; the second group of cross-flow filtering assemblies comprises second cross-flow filtering assemblies which are mounted on the concentrated solution main pipe in a one-to-one correspondence manner with the first cross-flow filtering assemblies, and the concentrated solution output ends of the second cross-flow filtering assemblies are communicated with the concentrated solution main pipe; and the cross-flow filtering assembly series pipeline comprises a flow guide pipe which is connected between the concentrated solution output end of each first cross-flow filtering assembly and the to-be-filtered solution input end of the corresponding second cross-flow filtering assembly.

Description

Technical Field

[0001] The present invention relates to a cross-flow filtration device, as well as a method and equipment for removing impurities and purifying a nickel sulfate solution. Background Art

[0002] Nickel sulfate is an important nickel compound, which is widely used in fields such as electroplating, nickel batteries, and catalyst production. Nickel sulfate mainly comes from the smelting of nickel ores (sulfide nickel ores and laterite nickel ores). Nickel ore smelting processes are mainly divided into two categories: wet processes and pyrometallurgical processes. Wet processes include high-pressure ammonia leaching, high-pressure acid leaching, and reduction roasting-acid leaching processes, while pyrometallurgical processes include electric furnace melting, flash furnace melting, and blast furnace smelting. Nickel ore smelting is an upstream resource development link, providing necessary nickel-containing raw materials for nickel sulfate production, and the two form a close industrial chain relationship. The matte nickel, nickel iron, nickel oxide, or nickel-containing solution produced during nickel ore smelting becomes the direct raw material for nickel sulfate production.

[0003] The production of nickel sulfate mainly adopts the following three methods: the sulfuric acid method, the extraction method, and the leaching method. The sulfuric acid method uses sodium carbonate precipitation to prepare nickel carbonate and then converts it into nickel sulfate; the extraction method is mainly used to remove sodium ions in the solution; the leaching method directly uses matte nickel as the raw material, leaches it with sulfuric acid, and then crystallizes to obtain the product. However, various impurities such as metal ions of iron, copper, cobalt, manganese, zinc, and lead will be introduced during nickel ore smelting, and these impurities will affect the quality of the final nickel sulfate product.

[0004] To obtain high-purity nickel sulfate, various purification technologies are adopted in industrial production to remove these impurities from the smelting process. The chemical purification method uses the precipitation differences of different metals at different pH values to remove impurities such as iron and copper; the organic solvent extraction method can selectively extract nickel ions and effectively separate ions such as sodium and calcium; the ion exchange method is suitable for deeply removing trace impurities such as lead and zinc; the liquid membrane separation method, electrodialysis method, and crystallization separation method are used for further purification. The selection of these purification technologies directly depends on the types and contents of impurities in the upstream smelting products, reflecting the close connection between nickel ore smelting and nickel sulfate production processes.

[0005] During the above purification process, a filter is required to remove suspended solids and particulate impurities in the nickel sulfate solution. Currently, a filter using a polyethylene (PE) filter element, abbreviated as a PE filter, is mainly used. Since the nickel sulfate solution has certain corrosiveness and a low pH value, the PE material is widely used due to its good acid and alkali corrosion resistance and relatively low cost. However, the PE filter has problems such as limited filtration accuracy, short service life, easy blockage, and low filtration efficiency, resulting in a large amount of fine suspended solids and colloidal impurities still remaining in the filtered nickel sulfate solution, making it difficult to meet the requirements of high-purity nickel sulfate (especially battery-grade nickel sulfate).

[0006] The applicant has noticed that, as a new type of filtration medium, silicon carbide ceramic filter elements have potentially great advantages in the field of impurity removal and purification of nickel sulfate solution. Compared with polyethylene (PE) filter elements, silicon carbide ceramic filter elements have a higher initial flux (600 - 800 L / m 2 h vs. 200 - 400 L / m 2 h) and better flux retention rate (it can still maintain 85% after 100 hours, while PE filter elements usually only maintain 30%). Experiments have shown that after filtering with silicon carbide ceramic filter elements, the content of impurity ions (such as Fe, Cu) in the nickel sulfate solution has decreased significantly, and the mass content of nickel sulfate can be increased from 99.96% to 99.99%, meeting the battery-grade nickel sulfate standard.

[0007] However, in the process of developing a silicon carbide filter element filter suitable for nickel sulfate solution, the following challenges are still encountered: First, according to the structural design of traditional cross-flow filters, a single cross-flow filter realizes primary filtration. Therefore, to adopt a staged cross-flow filtration method, different cross-flow filters need to be connected in series. This not only results in a large floor area for the entire cross-flow filtration system, but also the different cross-flow filters connected in series need to be equipped with their own circulation pipelines and control systems, increasing the equipment investment cost, energy consumption, and maintenance difficulty.

[0008] Second, currently, the commercially available silicon carbide ceramic filter elements for cross-flow filtration are mainly internal filtration type columnar cross-flow filtration filter elements (referring to the cross-flow filtration filter elements in the shape of a hollow cylinder where the liquid to be filtered penetrates from the inside of the filter element to the outside, impurities are intercepted by the inner wall of the filter element, and the clear liquid passes through the filter element wall and is collected outside the filter element), and most of them are multi-channel internal filtration type columnar cross-flow filtration filter elements ("multi-channel" means that there are multiple axial channels in the filter element). Since silicon carbide is a material with relatively large brittleness, the length of this type of internal filtration type columnar cross-flow filtration filter element is relatively short, and the filtration area of a single internal filtration type columnar cross-flow filtration filter element is relatively small. This leads to the need to use a large number of internal filtration type columnar cross-flow filtration filter elements in parallel in traditional cross-flow filters to obtain sufficient filtration area and throughput.

[0009] Third, in traditional cross-flow filters, the traditional installation method of internal filtration type columnar cross-flow filtration filter elements requires applying a certain axial load to the internal filtration type columnar cross-flow filtration filter elements, and since silicon carbide is a material with relatively large brittleness, this traditional installation method is likely to cause the internal filtration type columnar cross-flow filtration filter elements to break and be damaged.

[0010] Fourth, from the filtration experiment of nickel sulfate solution using a multi-channel internal filtration columnar cross-flow filtration filter element, it is found that: the liquid inlet end of the multi-channel internal filtration columnar cross-flow filtration filter element is more likely to be blocked than other parts of the multi-channel internal filtration columnar cross-flow filtration filter element. The reason for the analysis is that: since the liquid inlet of the multi-channel internal filtration columnar cross-flow filtration filter element is at the initial contact position between the multi-channel internal filtration columnar cross-flow filtration filter element and the liquid to be filtered, the concentration of suspended particles, impurities and precipitates in the nickel sulfate solution is the highest here, and the metal ions in the nickel sulfate solution are prone to aggregation to form insoluble precipitates or colloids. In addition, when the liquid to be filtered enters the multi-channel internal filtration columnar cross-flow filtration filter element, there will be a sharp change in the flow direction and a turbulent flow phenomenon, resulting in the formation of a low-speed area or a vortex area at the liquid inlet end, which is conducive to the settlement and attachment of suspended particles. Summary of the Invention

[0011] In the first aspect, a cross-flow filtration device is provided, which mainly solves the technical problems of large floor area and high cost of the entire cross-flow filtration system caused by the current series arrangement of different cross-flow filters.

[0012] To solve such technical problems, the cross-flow filtration device in the first aspect includes: a circulation pipeline, including a main pipeline for the liquid to be filtered and a main pipeline for the concentrated liquid. During operation, the main pipeline for the liquid to be filtered and the main pipeline for the concentrated liquid are connected in series through a circulation pump; a first group of cross-flow filtration components, including at least two first cross-flow filtration components installed side by side on the main pipeline for the filtered liquid and the liquid input end to be filtered is communicated with the main pipeline for the filtered liquid; a second group of cross-flow filtration components, including second cross-flow filtration components installed corresponding to each first cross-flow filtration component on the main pipeline for the concentrated liquid, and the concentrated liquid output end is communicated with the main pipeline for the concentrated liquid; a cross-flow filtration component series pipeline, including a diversion pipe connected between the concentrated liquid output end of each first cross-flow filtration component and the liquid input end to be filtered of the corresponding second cross-flow filtration component; during operation, the liquid to be filtered in the main pipeline for the liquid to be filtered enters each first cross-flow filtration component respectively for the first cross-flow filtration to separate into a first concentrated liquid and a first clear liquid, the first concentrated liquid enters the corresponding second cross-flow filtration component through the corresponding diversion pipe respectively for the second cross-flow filtration to separate into a second concentrated liquid and a second clear liquid, the second concentrated liquid is collected into the main pipeline for the concentrated liquid and then returned to the main pipeline for the liquid to be filtered through the circulation pump, and the first clear liquid and the second clear liquid are discharged from the cross-flow filtration device.

[0013] On the basis of the cross-flow filter device of the first aspect above, in order to further solve the technical problems of optimizing the spatial layout structure of the cross-flow filter device and improving the space utilization efficiency and engineering practicality, the following are adopted: the main pipe of the liquid to be filtered and the main pipe of the concentrated liquid are arranged in parallel in the horizontal direction; each of the first cross-flow filter components is a vertical cross-flow filter component and is installed in parallel above the main pipe of the liquid to be filtered, the lower end of each of the first cross-flow filter components is the input end of the liquid to be filtered and the upper end is the output end of the concentrated liquid; each of the second cross-flow filter components is a vertical cross-flow filter component and is installed in parallel above the main pipe of the concentrated liquid, the upper end of each of the second cross-flow filter components is the input end of the liquid to be filtered and the lower end is the output end of the concentrated liquid; each of the flow guide pipes is respectively connected between the upper end of the corresponding first cross-flow filter component and the upper end of the corresponding second cross-flow filter component.

[0014] On the basis of the cross-flow filter device of the first aspect mentioned above, in order to further solve the technical problem of optimizing the internal structure of the cross-flow filter assembly and realizing efficient liquid separation and circulation, the following are the following: each first cross-flow filter assembly and each second cross-flow filter assembly structure includes an outer cylinder and an inner filter type columnar cross-flow filter element installed in the outer cylinder through a first end positioning and mounting sealing structure of the filter element and a second end positioning and mounting sealing structure of the filter element; a clear liquid cavity is formed between the outer cylinder and the inner filter type columnar cross-flow filter element and between the first end positioning and mounting sealing structure of the filter element and the second end positioning and mounting sealing structure of the filter element, and a clear liquid output port which is in communication with the clear liquid cavity is provided on the outer cylinder; a clear liquid output port which is in communication with the clear liquid cavity is provided in the outer cylinder of each first cross-flow filter assembly; a clear liquid output port which is in communication with the clear liquid output port is provided in the outer cylinder of each first cross-flow filter assembly; a clear liquid output port which is in communication with the clear liquid output port is provided in the outer cylinder of each first cross-flow filter assembly; a clear liquid output port which is in communication with the clear liquid output port is provided The area above the installed sealing structure is the concentrated liquid chamber, the concentrated liquid output end of the first cross-flow filter assembly is connected to the concentrated liquid chamber, the area below the positioning and installing sealing structure at the second end of the filter element in the outer cylinder of each first cross-flow filter assembly forms a liquid chamber to be filtered, and the input end of the liquid to be filtered of the first cross-flow filter assembly is connected to the liquid chamber to be filtered; the area above the positioning and installing sealing structure at the first end of the filter element in the outer cylinder of each second cross-flow filter assembly is the liquid chamber to be filtered, the input end of the liquid to be filtered of the second cross-flow filter assembly is connected to the liquid chamber to be filtered, the area below the positioning and installing sealing structure at the second end of the filter element in the outer cylinder of each second cross-flow filter assembly forms a concentrated liquid chamber, and the concentrated liquid output end of the second cross-flow filter assembly is connected to the concentrated liquid chamber.

[0015] On the basis of the cross-flow filtration device of the first aspect above, in order to further solve the technical problem of improving the filtration efficiency of the inner-filtration columnar cross-flow filter element, the inner-filtration columnar cross-flow filter element adopts a multi-channel inner-filtration columnar cross-flow filter element.

[0016] Based on the cross-flow filtration device in the first aspect above, to further solve the technical problems of improving the filtration performance and corrosion resistance of the internal filtration columnar cross-flow filtration filter element, the following is adopted: The multi-channel internal filtration columnar cross-flow filtration filter element is made of silicon carbide material; the silicon carbide material has an asymmetric membrane structure including a silicon carbide filter membrane layer, a silicon carbide transition layer, and a silicon carbide support layer arranged in sequence along the liquid penetration direction.

[0017] Based on the cross-flow filtration device in the first aspect above, to further solve the technical problem of effectively preventing the fracture of the internal filtration columnar cross-flow filtration filter element, the following is adopted: The positioning and installation sealing structure at the first end of the filter element and the positioning and installation sealing structure at the second end of the filter element both include an inner plate member and an outer plate member that are stacked and installed. The inner plate member is distributed with first stepped holes, and the outer plate member is distributed with second stepped holes that are coaxially arranged in one-to-one correspondence with the first stepped holes; the first stepped holes are sleeved on the corresponding internal filtration columnar cross-flow filtration filter element. The small-hole end of the first stepped hole and the large-hole end of the second stepped hole both face the middle direction of the internal filtration columnar cross-flow filtration filter element. The inner diameter of the small-hole end of the first stepped hole is larger than the outer diameter of the internal filtration columnar cross-flow filtration filter element, the inner diameter of the large-hole end of the second stepped hole is smaller than the inner diameter of the large-hole end of the first stepped hole, and the inner diameter of the small-hole end of the second stepped hole is smaller than the outer diameter of the internal filtration columnar cross-flow filtration filter element; a sealing component is installed on the large-hole wall of the first stepped hole. The sealing component is axially extruded between the internal stepped surface of the first stepped hole and the end surface of the outer plate member and includes at least one sealing ring and at least one sealing ring pressing ring. The inner walls of these sealing rings are closely attached to the outer wall of the corresponding internal filtration columnar cross-flow filtration filter element; the distance between the internal stepped surface of the second stepped hole in the positioning and installation sealing structure at the first end of the filter element and the internal stepped surface of the second stepped hole in the positioning and installation sealing structure at the second end of the filter element is greater than the length of the internal filtration columnar cross-flow filtration filter element.

[0018] Based on the cross-flow filtration device in the first aspect above, to further solve the technical problem of easy blockage at the liquid inlet end of the multi-channel internal filtration columnar cross-flow filtration filter element, the following is adopted: A multi-channel internal filtration columnar cross-flow filtration filter element liquid inlet blocking ring is detachably installed in the small-hole channels of the second stepped holes in the positioning and installation sealing structure at the second end of the filter element of each first cross-flow filtration component and / or the positioning and installation sealing structure at the first end of the filter element of each second cross-flow filtration component. The multi-channel internal filtration columnar cross-flow filtration filter element liquid inlet blocking ring includes a blocking ring body, and the blocking ring body is densely distributed with liquid inlet through holes, and these liquid inlet through holes are used to introduce the liquid to be filtered flowing through the small-hole channel to the liquid inlet end of the multi-channel internal filtration columnar cross-flow filtration filter element into the liquid inlet end of the multi-channel internal filtration columnar cross-flow filtration filter element.

[0019] Based on the cross-flow filtration device in the above first aspect, to further solve the technical problem of providing a supply channel for the external liquid to be filtered for the cross-flow filtration device, then: The cross-flow filtration device further includes a liquid inlet pipeline, and the liquid inlet pipeline is connected to the main liquid pipeline to be filtered and / or the main concentrated liquid pipeline, and is used to provide a supply channel for the external liquid to be filtered.

[0020] Based on the cross-flow filtration device in the above first aspect, to further solve the technical problem of providing a concentrated liquid discharge channel for the cross-flow filtration device and optimizing the concentrated liquid treatment capacity of the cross-flow filtration device, then: The cross-flow filtration device further includes a concentrated liquid pipeline, and the concentrated liquid pipeline is connected to the main liquid pipeline to be filtered and / or the main concentrated liquid pipeline, and is used to provide a concentrated liquid discharge channel.

[0021] Based on the cross-flow filtration device in the above first aspect, to further solve the technical problem of providing a clear liquid collection and discharge channel for the cross-flow filtration device, then: The cross-flow filtration device further includes a clear liquid pipeline, and the clear liquid pipeline is connected to the clear liquid outlets of each first cross-flow filtration component and each second cross-flow filtration component, and is used to provide a discharge channel for the first clear liquid and the second clear liquid.

[0022] Based on the cross-flow filtration device in the above first aspect, to further solve the technical problem that gas accumulation may occur in the cross-flow filtration device and is not easy to discharge, then: When the main liquid pipeline to be filtered and the main concentrated liquid pipeline are arranged in parallel in the horizontal direction, each first cross-flow filtration component is a vertical cross-flow filtration component and is installed in parallel above the main liquid pipeline to be filtered, the lower end of each first cross-flow filtration component is the liquid input end to be filtered and the upper end is the concentrated liquid output end, each second cross-flow filtration component is a vertical cross-flow filtration component and is installed in parallel above the main concentrated liquid pipeline, the upper end of each second cross-flow filtration component is the liquid input end to be filtered and the lower end is the concentrated liquid output end, and each diversion pipe is respectively connected between the upper end of the corresponding first cross-flow filtration component and the upper end of the corresponding second cross-flow filtration component, then each diversion pipe is an inverted U-shaped pipe, and an exhaust pipeline is also connected to the top of each inverted U-shaped pipe.

[0023] In the second aspect, a method for purifying nickel sulfate solution by removing impurities is provided to solve the technical problem of applying the cross-flow filtration device in the above first aspect to the purification of nickel sulfate solution by removing impurities. The method for purifying nickel sulfate solution by removing impurities in the second aspect includes the step of performing ultrafiltration treatment on the nickel sulfate solution raw material obtained by nickel ore smelting through the cross-flow filtration device in the above first aspect.

[0024] In the third aspect, a device for purifying nickel sulfate solution by removing impurities is provided to solve the technical problem of applying the cross-flow filtration device in the above first aspect to the purification of nickel sulfate solution by removing impurities. The device for purifying nickel sulfate solution by removing impurities in the third aspect includes the cross-flow filtration device in the above first aspect, and the cross-flow filtration device is used to perform ultrafiltration treatment on the nickel sulfate solution raw material obtained by nickel ore smelting.

[0025] The above cross-flow filtration device of the present invention integrates a first group of cross-flow filtration components and a second group of cross-flow filtration components, and the first group of cross-flow filtration components and the second group of cross-flow filtration components share a circulation pipeline. During operation, the liquid to be filtered in the main pipeline of the liquid to be filtered enters each first cross-flow filtration component respectively for the first cross-flow filtration (primary cross-flow filtration) to separate and form a first concentrated liquid and a first clear liquid. The first concentrated liquid enters the corresponding second cross-flow filtration component through the corresponding diversion pipe respectively for the second cross-flow filtration (secondary cross-flow filtration) to separate and form a second concentrated liquid and a second clear liquid. The second concentrated liquid is collected in the main pipeline of the concentrated liquid and then returned to the main pipeline of the liquid to be filtered through a circulation pump, and the first clear liquid and the second clear liquid are discharged from the cross-flow filtration device. It can be seen that this cross-flow filtration device can effectively solve the problems in the structural design of traditional cross-flow filters, such as large floor area, high equipment investment cost, high energy consumption, and great maintenance difficulty of the entire cross-flow filtration system caused by the need to use different cross-flow filters connected in series in a hierarchical cross-flow filtration method when a single cross-flow filter is used to achieve primary filtration.

[0026] In addition, the above cross-flow filtration device of the present invention also expands the overall filtration area ingeniously without additional floor area by connecting the first group of cross-flow filtration components and the second group of cross-flow filtration components in series in a "one-to-one" manner, and at the same time, each cross-flow filtration component is installed side by side in the same circulation pipeline. In the present invention, a unified circulation pipeline is formed by connecting the main pipeline of the liquid to be filtered and the main pipeline of the concentrated liquid in series through a circulation pump. The concentrated liquid output end of each first cross-flow filtration component is directly connected to the liquid to be filtered input end of the corresponding second cross-flow filtration component through a diversion pipe, forming multiple parallel series filtration paths, so that even if a multi-channel internal filtration type columnar cross-flow filtration filter element made of silicon carbide with a small single filtration area is used, the cross-flow filtration device can still provide sufficient total filtration area and throughput.

[0027] In addition, by installing the first group of cross-flow filtration components and the second group of cross-flow filtration components on the main pipeline of the liquid to be filtered and the main pipeline of the concentrated liquid respectively and connecting them flexibly through a diversion pipe, it is convenient to disassemble, clean and replace each cross-flow filtration component separately, greatly improving the maintenance efficiency and service life of the cross-flow filtration device.

[0028] The following further describes the present invention in conjunction with the drawings and specific embodiments. The additional aspects and advantages provided by the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings forming a part of this specification are used to assist in understanding the present invention. The content provided in the drawings and the related description in this specification can be used to explain the present invention, but do not constitute an improper limitation to the present invention.

[0030] Figure 1 External view of the cross-flow filtration device (skid-mounted equipment) according to an embodiment of the present invention.

[0031] Figure 2 is Figure 1 Front view of the cross-flow filtration device shown.

[0032] Figure 3 is Figure 1 Top view of the cross-flow filtration device shown.

[0033] Figure 4 is Figure 1 Right view of the cross-flow filtration device shown.

[0034] Figure 5 is Figure 1 Enlarged view of the circulation pipeline in the cross-flow filtration device shown.

[0035] Figure 6 is Figure 1 Enlarged view of the evacuation pipeline in the cross-flow filtration device shown.

[0036] Figure 7 is Figure 1 Enlarged view of the concentrated liquid pipeline in the cross-flow filtration device shown.

[0037] Figure 8 is Figure 1 Enlarged view of the liquid inlet pipeline in the cross-flow filtration device shown.

[0038] Figure 9 is Figure 1 Enlarged view of the clear liquid pipeline in the cross-flow filtration device shown.

[0039] Figure 10 is Figure 1 Cross-sectional view of the first cross-flow filtration component in the cross-flow filtration device shown.

[0040] Figure 11 is Figure 10 Cross-sectional view of the positioning, installation and sealing structure at the first end of the filter element in the cross-flow filtration component shown.

[0041] Figure 12 is Figure 10 Cross-sectional view of the positioning, installation and sealing structure at the second end of the filter element in the cross-flow filtration component shown.

[0042] Figure 13 is Figure 10 Usage diagram of the positioning, installation and sealing structure at the first end of the filter element in the cross-flow filtration component shown.

[0043] Figure 14 is Figure 1 Physical photo of the multi-channel internal filtration type columnar cross-flow filtration filter element (made of silicon carbide material) used in the cross-flow filtration device shown.

[0044] Figure 15 For Figure 14 The micrograph of the asymmetric membrane structure of the multi-channel internal filtration columnar cross-flow filtration filter element (made of silicon carbide material) shown in the figure.

[0045] Figure 16 For Figure 10 The physical picture of the liquid inlet retaining ring of the multi-channel internal filtration columnar cross-flow filtration filter element in the cross-flow filtration assembly shown in the figure.

[0046] Figure 17 The PID (piping and instrumentation) diagram of the equipment for impurity removal and purification of nickel sulfate solution in the embodiment of the present invention.

[0047] The markings in the figure are: circulation pipeline 11, total pipeline 111 of the liquid to be filtered, total pipeline 112 of the concentrated liquid, first group of cross-flow filtration assemblies 12, first cross-flow filtration assembly 121, second group of cross-flow filtration assemblies 13, second cross-flow filtration assembly 131, series pipeline 14 of the cross-flow filtration assemblies, diversion pipe 141, exhaust pipeline 15, liquid inlet pipeline 16, concentrated liquid pipeline 17, clear liquid pipeline 18, outer cylinder 21, positioning and installation sealing structure 22 at the first end of the filter element, positioning and installation sealing structure 23 at the second end of the filter element, internal filtration columnar cross-flow filtration filter element 3, liquid inlet retaining ring 4 of the multi-channel internal filtration columnar cross-flow filtration filter element, intermediate cylinder 211, first end cylinder 212, second end cylinder 213, inner side plate member 241, outer side plate member 242, sealing ring 243, sealing ring pressing ring 244, first stepped hole H1, second stepped hole H2. Detailed implementation manners

[0048] The present invention will be described clearly and completely below with reference to the accompanying drawings. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be particularly noted that:

[0049] The technical solutions and technical features provided in each part including the following description can be combined with each other without conflict. In addition, where possible, these technical solutions, technical features and related combinations can be given specific technical themes and be protected by relevant patents.

[0050] The embodiments of the present invention involved in the following description are usually only some embodiments rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on these embodiments should fall within the scope of patent protection.

[0051] The terms "comprising", "including", "having" and any variations thereof in this specification, the corresponding claims and relevant parts are intended to cover non-exclusive inclusion. Other relevant terms and units can be reasonably interpreted based on the relevant content provided in this specification.

[0052] I. The cross-flow filtration device of the embodiment of the present invention.

[0053] As Figures 1 to 9 shown, the cross-flow filtration device of this embodiment mainly includes a circulation pipeline 11, a first group of cross-flow filtration components 12, a second group of cross-flow filtration components 13, and a cross-flow filtration component series pipeline 14.

[0054] The circulation pipeline 11 includes a total pipeline 111 for the liquid to be filtered and a total pipeline 112 for the concentrated liquid, and the two are arranged in parallel in the horizontal direction. During operation, the total pipeline 111 for the liquid to be filtered and the total pipeline 112 for the concentrated liquid are connected in series through a circulation pump (configured separately and not shown in the skid-mounted equipment), so that the concentrated liquid in the total pipeline 112 for the concentrated liquid can return to the total pipeline 111 for the filtered liquid through the circulation pump, and then circulate to the total pipeline 112 for the concentrated liquid through the first group of cross-flow filtration components 12, the cross-flow filtration component series pipeline 14, and the second group of cross-flow filtration components 13.

[0055] The first group of cross-flow filtration components 12 includes at least two first cross-flow filtration components 121 installed side by side above the total pipeline 111 for the liquid to be filtered. Each first cross-flow filtration component 121 is a vertical cross-flow filtration component, the lower end of which is the input end for the liquid to be filtered and is connected to the total pipeline 111 for the liquid to be filtered, and the upper end is the output end for the concentrated liquid.

[0056] The second group of cross-flow filtration components 13 includes second cross-flow filtration components 131 installed corresponding to each of the first cross-flow filtration components 121 above the total pipeline 112 for the concentrated liquid. Each second cross-flow filtration component 131 is also a vertical cross-flow filtration component, the upper end of which is the input end for the liquid to be filtered, and the lower end is the output end for the concentrated liquid and is connected to the total pipeline 112 for the concentrated liquid.

[0057] The cross-flow filtration component series pipeline 14 includes a diversion pipe 141 connected between the concentrated liquid output end of each first cross-flow filtration component 121 and the input end for the liquid to be filtered of the corresponding second cross-flow filtration component 131. Each diversion pipe 141 is an inverted U-shaped pipe (see Figure 1 and Figure 4 ), and an exhaust pipe 15 is also connected to the top of each inverted U-shaped pipe for discharging the gas accumulated in the cross-flow filtration device.

[0058] In addition, the cross-flow filtration device further includes a feed liquid pipeline 16, a concentrated liquid pipeline 17, and a clarified liquid pipeline 18. The feed liquid pipeline 16 is connected to the total pipeline 111 of the liquid to be filtered, and is used to provide a supply channel for the external liquid to be filtered. The concentrated liquid pipeline 17 is connected to the bottom of the total pipeline 111 of the liquid to be filtered and the total pipeline 112 of the concentrated liquid, and is used to provide an external discharge channel for the concentrated liquid. The clarified liquid pipeline 18 is connected to the clarified liquid outlets of each first cross-flow filtration module 121 and each second cross-flow filtration module 131, and is used to provide an external discharge channel for the first clarified liquid and the second clarified liquid.

[0059] When the above cross-flow filtration device operates, the liquid to be filtered in the total pipeline 111 of the liquid to be filtered respectively enters each first cross-flow filtration module 121 for first cross-flow filtration to separate into a first concentrated liquid and a first clarified liquid. The first concentrated liquid respectively enters the corresponding second cross-flow filtration module 131 through the corresponding diversion pipelines 141 for second cross-flow filtration to separate into a second concentrated liquid and a second clarified liquid. The second concentrated liquid is collected in the total pipeline 112 of the concentrated liquid and then returned to the total pipeline 111 of the liquid to be filtered through a circulation pump. The first clarified liquid and the second clarified liquid are discharged from the cross-flow filtration device.

[0060] The above cross-flow filtration device integrates a first group of cross-flow filtration modules 12 and a second group of cross-flow filtration modules 13. The first group of cross-flow filtration modules 12 and the second group of cross-flow filtration modules 13 share a circulation pipeline 11. When operating, the liquid to be filtered in the total pipeline 111 of the liquid to be filtered respectively enters each first cross-flow filtration module 121 for first cross-flow filtration (primary cross-flow filtration) to separate into a first concentrated liquid and a first clarified liquid. The first concentrated liquid respectively enters the corresponding second cross-flow filtration module 131 through the corresponding diversion pipelines 141 for second cross-flow filtration (secondary cross-flow filtration) to separate into a second concentrated liquid and a second clarified liquid. The second concentrated liquid is collected in the total pipeline 112 of the concentrated liquid and then returned to the total pipeline 111 of the liquid to be filtered through a circulation pump. The first clarified liquid and the second clarified liquid are discharged from the cross-flow filtration device. It can be seen that the cross-flow filtration device can effectively solve the problems of large floor area, high equipment investment cost, high energy consumption, and high maintenance difficulty of the entire cross-flow filtration system caused by the need to use different cross-flow filters connected in series in the structural design of traditional cross-flow filters when a single cross-flow filter is used to achieve primary filtration and a hierarchical cross-flow filtration method is adopted.

[0061] The cross-flow filtration device connects the first group of cross-flow filtration components 12 and the second group of cross-flow filtration components 13 in series in a "one-to-one" manner. At the same time, each cross-flow filtration component (the cross-flow filtration component is a general term for each first cross-flow filtration component 121 and each second cross-flow filtration component 131) is installed side by side in the same circulation pipeline 11, which not only cleverly expands the overall filtration area but also does not require additional equipment floor space. A unified circulation pipeline 11 is formed by connecting the total inlet pipe 111 of the liquid to be filtered and the total outlet pipe 112 of the concentrated liquid in series through a circulation pump. The concentrated liquid output end of each first cross-flow filtration component 121 is directly connected to the liquid-to-be-filtered input end of the corresponding second cross-flow filtration component 131 through a diversion pipe 141, forming multiple parallel series filtration paths. Even if a multi-channel internal filtration columnar cross-flow filtration filter element made of silicon carbide with a small single filtration area is used, the cross-flow filtration device can still provide sufficient total filtration area and throughput.

[0062] In addition, by installing the first group of cross-flow filtration components 121 and the second group of cross-flow filtration components 131 on the total inlet pipe 111 of the liquid to be filtered and the total outlet pipe 112 of the concentrated liquid respectively and flexibly connecting them through a diversion pipe, it is convenient to separately disassemble, clean, and replace each cross-flow filtration component, greatly improving the maintenance efficiency and service life of the cross-flow filtration device.

[0063] II. Structure of the cross-flow filtration component.

[0064] As Figures 10 to 13 shown, each first cross-flow filtration component 121 and each second cross-flow filtration component 131 (collectively referred to as cross-flow filtration components) have the same structure, and both include an outer cylinder 21 and an internal filtration columnar cross-flow filtration filter element 3 installed in the outer cylinder 21 through a filter element first-end positioning and installation sealing structure 22 and a filter element second-end positioning and installation sealing structure 23.

[0065] A clear liquid cavity is formed between the outer cylinder 21 and the internal filtration columnar cross-flow filtration filter element 3 and in the area between the filter element first-end positioning and installation sealing structure 22 and the filter element second-end positioning and installation sealing structure 23. The outer cylinder 21 is provided with a clear liquid outlet communicated with the clear liquid cavity.

[0066] The area above the filter element first-end positioning and installation sealing structure 22 in the outer cylinder 21 of each first cross-flow filtration component 121 is the concentrated liquid cavity, and the concentrated liquid output end of the first cross-flow filtration component 121 is communicated with the concentrated liquid cavity. The area below the filter element second-end positioning and installation sealing structure 23 in the outer cylinder 21 of each first cross-flow filtration component 121 forms a liquid-to-be-filtered cavity, and the liquid-to-be-filtered input end of the first cross-flow filtration component 121 is communicated with the liquid-to-be-filtered cavity.

[0067] For each second cross-flow filtration module 131, the area in the outer cylinder 21 above the filter element first-end positioning and installation sealing structure 22 is the liquid to be filtered chamber. The input end of the liquid to be filtered of the second cross-flow filtration module 131 communicates with the liquid to be filtered chamber. In the outer cylinder 21 of each second cross-flow filtration module 131, the area below the filter element second-end positioning and installation sealing structure 23 forms a concentrated liquid chamber. The output end of the concentrated liquid of the second cross-flow filtration module 131 communicates with the concentrated liquid chamber. It can be seen that both the first cross-flow filtration module 121 and the second cross-flow filtration module 131 adopt an internal filtration type columnar cross-flow filtration filter element 3, and are fixed in the outer cylinder 21 through the filter element first-end positioning and installation sealing structure 22 and the filter element second-end positioning and installation sealing structure 23. However, in terms of the flow direction, the liquid to be filtered of the first cross-flow filtration module 121 enters from the lower part, and the first concentrated liquid is output from the upper part; while for the second cross-flow filtration module 131, on the contrary, the liquid to be filtered (i.e., the first concentrated liquid) enters from the upper part, and the second concentrated liquid is output from the lower part. In this way, the first concentrated liquid of the first cross-flow filtration module 121 can directly enter the input end of the liquid to be filtered of the corresponding second cross-flow filtration module 131 through the diversion pipe 141, while maintaining the structural consistency of the first cross-flow filtration module 121 and the second cross-flow filtration module 131.

[0068] Among them, the internal filtration type columnar cross-flow filtration filter element 3 specifically adopts a multi-channel internal filtration type columnar cross-flow filtration filter element. More specifically, the multi-channel internal filtration type columnar cross-flow filtration filter element is made of silicon carbide material.

[0069] The traditional installation method of the internal filtration type columnar cross-flow filtration filter element 3 needs to apply a certain axial load to the internal filtration type columnar cross-flow filtration filter element 3, and silicon carbide belongs to a material with relatively large brittleness. This traditional installation method is likely to cause the internal filtration type columnar cross-flow filtration filter element 3 to break and be damaged. Therefore, during the design of the filter element first-end positioning and installation sealing structure and the filter element second-end positioning and installation sealing structure, the innovative concept of "non-pressurized floating support" is proposed, that is, by allowing the axial floating of the internal filtration type columnar cross-flow filtration filter element 3 to reduce the axial pressure on the internal filtration type columnar cross-flow filtration filter element 3, and at the same time using a more reasonable radial sealing method to ensure the sealing effect. Thus, the first-end positioning and installation sealing structure and the filter element second-end positioning and installation sealing structure are designed into the following structures and have been verified through actual tests.

[0070] The first-end positioning, mounting and sealing structure 22 of the filter element and the second-end positioning, mounting and sealing structure 23 of the filter element both include an inner plate member 241 and an outer plate member 242 which are stacked and mounted on each other. First stepped holes H1 are distributed on the inner plate member 241, and second stepped holes H2 which are coaxially arranged corresponding to the first stepped holes H1 one by one are distributed on the outer plate member 242. The first stepped holes H1 are sleeved on the corresponding inner-filter type columnar cross-flow filter element 3. The small-hole ends of the first stepped holes H1 and the large-hole ends of the second stepped holes H2 both face the middle direction of the inner-filter type columnar cross-flow filter element 3. The inner diameter D11 of the small-hole ends of the first stepped holes H1 is larger than the outer diameter D3 of the inner-filter type columnar cross-flow filter element 3. The inner diameter D22 of the large-hole ends of the second stepped holes H2 is smaller than the inner diameter D12 of the large-hole ends of the first stepped holes H1. The inner diameter D21 of the small-hole ends of the second stepped holes H2 is smaller than the outer diameter D3 of the inner-filter type columnar cross-flow filter element 3. A sealing assembly is mounted on the large-hole channel wall of the first stepped holes H1. The sealing assembly is axially extruded between the inner stepped surface of the first stepped holes H1 and the end surface of the outer plate member 242 and includes at least one sealing ring 243 and at least one sealing ring pressing ring 244. The inner walls of these sealing rings 243 are closely attached to the outer wall of the corresponding inner-filter type columnar cross-flow filter element 3. The distance between the inner stepped surface of the second stepped holes H2 in the first-end positioning, mounting and sealing structure 22 of the filter element and the inner stepped surface of the second stepped holes H2 in the second-end positioning, mounting and sealing structure 23 of the filter element is larger than the length of the inner-filter type columnar cross-flow filter element 3.

[0071] The inner-filter type columnar cross-flow filter element 3 is mounted through the specially designed first-end positioning, mounting and sealing structure 22 and the second-end positioning, mounting and sealing structure 23 of the filter element. The inner diameter D11 of the small-hole ends of the first stepped holes H1 is larger than the outer diameter of the inner-filter type columnar cross-flow filter element 3 to form a gap, and the inner walls of the sealing rings 243 are closely attached to the outer wall of the filter element to form a flexible seal. Moreover, the distance between the inner stepped surface of the second stepped holes H2 in the first-end positioning, mounting and sealing structure 22 of the filter element and the inner stepped surface of the second stepped holes H2 in the second-end positioning, mounting and sealing structure 23 of the filter element is larger than the length of the inner-filter type columnar cross-flow filter element 3, avoiding a large axial force on the inner-filter type columnar cross-flow filter element 3 and effectively reducing the risk of fracture of the inner-filter type columnar cross-flow filter element 3, especially the inner-filter type columnar cross-flow filter element 3 made of brittle materials such as silicon carbide, during installation and use.

[0072] Generally speaking, the inner plate member 241 and the outer plate member 242 which are stacked and mounted on each other are connected by threaded connectors.

[0073] In a preferred embodiment, the outer cylinder 21 is divided into an intermediate cylinder 211, a first end cylinder 212 and a second end cylinder 213 respectively located at both ends of the intermediate cylinder 211; the first end cylinder 212 and the intermediate cylinder 211 are butt-jointed through a first group of flanges, and the first group of flanges includes a first intermediate cylinder side flange fixed on the intermediate cylinder 211 and a first end cylinder side flange fixed on the first end cylinder 212, and the first intermediate cylinder side flange and the inner plate member 241 of the positioning and mounting sealing structure 22 at the first end of the filter element are formed by the same plate member; the second end cylinder 213 and the intermediate cylinder 211 are butt-jointed through a second group of flanges, and the second group of flanges includes a second intermediate cylinder side flange fixed on the intermediate cylinder 211 and a second end cylinder side flange fixed on the second end cylinder 213, and the second intermediate cylinder side flange and the inner plate member 241 of the positioning and mounting sealing structure 23 at the second end of the filter element are formed by the same plate member.

[0074] The first group of flanges further includes a first intermediate flange formed by extending outward from the edge of the outer plate member 242 of the positioning and mounting sealing structure 22 at the first end of the filter element, and the first intermediate flange is clamped between the first intermediate cylinder side flange and the first end cylinder side flange.

[0075] The second group of flanges further includes a second intermediate flange formed by extending outward from the edge of the outer plate member 242 of the positioning and mounting sealing structure 23 at the second end of the filter element, and the second intermediate flange is clamped between the second intermediate cylinder side flange and the second end cylinder side flange.

[0076] By designing the outer cylinder 21 of the cross-flow filtration module as a combined structure of an intermediate cylinder 211 and first end cylinders 212 and second end cylinders 213 at both ends, and innovatively making the inner plate member 241 of the positioning and mounting sealing structure 22 at the first end of the filter element and the first intermediate cylinder side flange be formed by the same plate member, making the inner plate member 241 of the positioning and mounting sealing structure 23 at the second end of the filter element and the second intermediate cylinder side flange be formed by the same plate member, and at the same time extending the edge of the outer plate member 242 of the positioning and mounting sealing structure 22 at the first end of the filter element outward to form a first intermediate flange and clamping it between the first intermediate cylinder side flange and the first end cylinder side flange, and extending the edge of the outer plate member 242 of the positioning and mounting sealing structure 23 at the second end of the filter element outward to form a second intermediate flange and clamping it between the second intermediate cylinder side flange and the second end cylinder side flange, the high integration and modularization of the structure are achieved. This design not only simplifies the number of parts, reduces the manufacturing cost, but also makes the entire cross-flow filtration module convenient to disassemble and recombine during maintenance.

[0077] In addition, generally, end face sealing rings are provided between each end face mating pair in the first group of flanges, and similarly, end face sealing rings are provided between each end face mating pair in the second group of flanges.

[0078] III. Multi-channel internal filtration columnar cross-flow filtration filter element.

[0079] Figure 14 The Figure 1 physical photo of the multi-channel internal filtration columnar cross-flow filtration filter element (made of silicon carbide material) used in the cross-flow filtration device shown. Figure 15 The Figure 14 microscopic photo of the asymmetric membrane structure of the multi-channel internal filtration columnar cross-flow filtration filter element (made of silicon carbide material) shown.

[0080] As Figures 14 - 15 shown, the multi-channel internal filtration columnar cross-flow filtration filter element made of silicon carbide material is used in the above cross-flow filtration device and cross-flow filtration module. Among them, the silicon carbide material has an asymmetric membrane structure including a silicon carbide filter membrane layer, a silicon carbide transition layer, and a silicon carbide support layer arranged in sequence along the liquid penetration direction.

[0081] The asymmetric membrane structure adopted by the multi-channel internal filtration columnar cross-flow filtration filter element made of silicon carbide material consists of three components with clear functions: the innermost silicon carbide filter membrane layer serves as the actual filtration layer, having precisely controlled micro-nano scale pore diameters (the average pore diameter of the silicon carbide filter membrane layer in this embodiment is 40 nm), responsible for intercepting particulate matter of specific sizes, and is the key part determining the separation accuracy of the filter element; the middle silicon carbide transition layer serves as a connection layer, having a pore diameter distribution gradually increasing from outside to inside (the average pore diameter of the silicon carbide transition layer in this embodiment is 0.5 microns), providing support for the upper filter membrane and reducing the liquid penetration resistance to ensure a smooth change in resistance when the fluid passes through each layer; the outermost silicon carbide support layer has larger pore diameters (the average pore diameter of the silicon carbide support layer in this embodiment is 8 microns), providing structural stability and compressive resistance for the entire multi-channel internal filtration columnar cross-flow filtration filter element, enabling the multi-channel internal filtration columnar cross-flow filtration filter element to withstand the high pressure and shear force during the cross-flow filtration process.

[0082] IV. Liquid inlet retaining ring of the multi-channel internal filtration columnar cross-flow filtration filter element.

[0083] In the filtration experiment of nickel sulfate solution using the above multi-channel inner filter columnar cross-flow filter element, it was found that the liquid inlet end of the multi-channel inner filter columnar cross-flow filter element is more prone to clogging than other parts of the multi-channel inner filter columnar cross-flow filter element. The reason for this is that the liquid inlet of the multi-channel inner filter columnar cross-flow filter element is at the initial contact position between the multi-channel inner filter columnar cross-flow filter element and the liquid to be filtered, where the concentration of suspended particles, impurities and sediments in the nickel sulfate solution is the highest, and the metal ions in the nickel sulfate solution are easy to aggregate to form insoluble precipitation or colloids. In addition, when the liquid to be filtered enters the multi-channel inner filter columnar cross-flow filter element, a sharp change in flow direction and turbulence will occur, resulting in the formation of a low-speed area or eddy current area at the liquid inlet end, which is conducive to the sedimentation and attachment of suspended particles.

[0084] Therefore, as an improvement, a multi-channel inner filter type columnar cross-flow filter element liquid inlet retaining ring 4 is detachably installed in the small hole channels of each second step hole H2 in the sealing structure 23 positioned and installed at the second end of the filter element of each first cross-flow filter assembly 121. The multi-channel inner filter type columnar cross-flow filter element liquid inlet retaining ring 4 comprises a retaining ring body, and the retaining ring body is densely covered with liquid inlet through holes. These liquid inlet through holes are used to introduce the to-be-filtered liquid that flows through the small hole channels to the liquid inlet end of the multi-channel inner filter type columnar cross-flow filter element into the liquid inlet end of the multi-channel inner filter type columnar cross-flow filter element.

[0085] The liquid inlet baffle ring 4 of the multi-channel inner-filter columnar cross-flow filter element allows the liquid to be filtered to first pass through the liquid inlet hole before entering the multi-channel inner-filter columnar cross-flow filter element, thereby preventing large particles of impurities from directly contacting and clogging the liquid inlet end of the multi-channel inner-filter columnar cross-flow filter element. At the same time, the detachable design of the baffle ring is convenient for cleaning and replacement, which effectively extends the service life of the multi-channel inner-filter columnar cross-flow filter element and improves the stability of the cross-flow filter assembly.

[0086] In this embodiment, one end of the retaining ring body is provided with a filter element installation countersunk hole, and the liquid inlet end of the multi-channel inner filter type columnar cross-flow filter element is adapted to be installed in the filter element installation countersunk hole. This design enables the liquid inlet end of the multi-channel inner filter type columnar cross-flow filter element to be accurately positioned on the retaining ring body, ensuring that the liquid to be filtered can be directly and evenly introduced into each channel of the multi-channel inner filter type columnar cross-flow filter element after passing through the liquid inlet through hole, thereby avoiding the uneven filtering phenomenon caused by the obstruction of some channels.

[0087] In order to ensure that the liquid inlet retaining ring 4 of the multi-channel inner filter columnar cross-flow filter element does not escape from its installation position during use, an axial positioning structure for axially cooperating with a corresponding positioning structure on the liquid inlet channel to prevent the retaining ring body from escaping from the liquid inlet channel is provided on the outer side wall of the retaining ring body. Specifically, the axial positioning structure is a flange, which directly cooperates with the corresponding second step hole to form a reliable axial positioning.

[0088] In practical applications, when in use, the axial force exerted by the liquid inlet end of the multi-channel internal filtration columnar cross-flow filtration filter element on the retaining ring body and the axial force exerted by the second stepped hole on the flange are a pair of reverse forces. This force balance design enables the liquid inlet retaining ring 4 of the multi-channel internal filtration columnar cross-flow filtration filter element to be in a stable stress state and will not shift or loosen due to the impact force generated by liquid flow.

[0089] The liquid inlet retaining ring 4 of the multi-channel internal filtration columnar cross-flow filtration filter element is a plastic integrally formed part. This integrated design avoids the leakage risk caused by complex assembly and also reduces the manufacturing cost. Considering the characteristics of corrosive liquids such as nickel sulfate solution, the liquid inlet retaining ring 4 of the multi-channel internal filtration columnar cross-flow filtration filter element is made of polytetrafluoroethylene material. Polytetrafluoroethylene has excellent chemical corrosion resistance, a low coefficient of friction, and good temperature stability, and can work stably for a long time under various harsh working conditions without affecting the filtration effect due to chemical reactions or physical deformations.

[0090] The above cross-flow filtration device is assembled into a device for purifying nickel sulfate solution from impurities (as Figure 17 shown). This device for purifying nickel sulfate solution from impurities is composed of three of the above cross-flow filtration devices connected in parallel, and these cross-flow filtration devices are used for ultrafiltration treatment of the nickel sulfate solution raw material obtained from nickel ore smelting.

[0091] The above has described the relevant content of the present invention. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. Based on the above content of this specification, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of the present invention.

Claims

1. A cross-flow filtration device, characterized in that: include: The circulation pipeline includes a main pipe for the liquid to be filtered and a main pipe for the concentrated liquid. When working, the main pipe for the liquid to be filtered and the main pipe for the concentrated liquid are connected in series through a circulation pump; The first group of cross-flow filter components comprises at least two first cross-flow filter components which are installed in parallel on the filtrate main pipe and the input end of the filtrate to be filtered is connected to the filtrate main pipe; A second group of cross-flow filter components, including second cross-flow filter components installed on the concentrate main pipe in one-to-one correspondence with each first cross-flow filter component, and the concentrate output end is in conduction with the concentrate main pipe; A cross-flow filter assembly series pipeline includes a flow guide pipe connected between a concentrated liquid output end of each first cross-flow filter assembly and a to-be-filtered liquid input end of a second cross-flow filter assembly corresponding to the first cross-flow filter assembly; During operation, the liquid to be filtered in the main pipe of the liquid to be filtered enters each first cross-flow filtration component for first cross-flow filtration to separate into a first concentrated liquid and a first clear liquid. The first concentrated liquid enters the corresponding second cross-flow filtration component through the corresponding guide pipe for second cross-flow filtration to separate into a second concentrated liquid and a second clear liquid. The second concentrated liquid is collected in the concentrated liquid main pipe and then returned to the main pipe of the liquid to be filtered through a circulation pump. The first clear liquid and the second clear liquid are discharged from the cross-flow filtration device.

2. The cross-flow filtration device according to claim 1, characterized in that: The main pipe for the liquid to be filtered and the main pipe for the concentrated liquid are arranged in parallel in the horizontal direction; Each first cross-flow filter assembly is a vertical cross-flow filter assembly and is installed in parallel above the main pipe of the liquid to be filtered. The lower end of each first cross-flow filter assembly is the input end of the liquid to be filtered and the upper end is the output end of the concentrated liquid. Each second cross-flow filter assembly is a vertical cross-flow filter assembly and is installed in parallel above the concentrated liquid main pipe. The upper end of each second cross-flow filter assembly is an input end for the liquid to be filtered and the lower end is an output end for the concentrated liquid. Each flow guide pipe is respectively connected between the upper end of the corresponding first cross-flow filter assembly and the upper end of the corresponding second cross-flow filter assembly.

3. The cross-flow filtration device according to claim 2, characterized in that: Each first cross-flow filter assembly and each second cross-flow filter assembly structure comprises an outer cylinder and an inner filter columnar cross-flow filter element installed in the outer cylinder through a first end positioning and mounting sealing structure of the filter element and a second end positioning and mounting sealing structure of the filter element; A clear liquid cavity is formed between the outer cylinder and the inner filter columnar cross-flow filter element and between the first end positioning and mounting sealing structure of the filter element and the second end positioning and mounting sealing structure of the filter element. A clear liquid outlet communicating with the clear liquid cavity is provided on the outer cylinder; The area of ​​the outer cylinder of each first cross-flow filter assembly located above the sealing structure for positioning and installing the first end of the filter element is a concentrated liquid chamber, the concentrated liquid output end of the first cross-flow filter assembly is in communication with the concentrated liquid chamber, the area of ​​the outer cylinder of each first cross-flow filter assembly located below the sealing structure for positioning and installing the second end of the filter element forms a liquid chamber to be filtered, and the liquid input end to be filtered of the first cross-flow filter assembly is in communication with the liquid chamber to be filtered; The area in the outer cylinder of each second cross-flow filter assembly located above the sealing structure for positioning and installing the first end of the filter element is a liquid chamber to be filtered, and the liquid input end to be filtered of the second cross-flow filter assembly is connected to the liquid chamber to be filtered. The area in the outer cylinder of each second cross-flow filter assembly located below the sealing structure for positioning and installing the second end of the filter element forms a concentrated liquid chamber, and the concentrated liquid output end of the second cross-flow filter assembly is connected to the concentrated liquid chamber.

4. The cross-flow filtration device according to claim 3, characterized in that: The inner filter type columnar cross-flow filter element adopts a multi-channel inner filter type columnar cross-flow filter element.

5. The cross-flow filtration device according to claim 4, characterized in that: The multi-channel inner-filter columnar cross-flow filter element is made of silicon carbide material; the silicon carbide material has an asymmetric membrane structure including a silicon carbide filter membrane layer, a silicon carbide transition layer and a silicon carbide support layer sequentially arranged along the liquid penetration direction.

6. The cross-flow filtration device according to claim 5, characterized in that: The first end positioning and installation sealing structure of the filter element and the second end positioning and installation sealing structure of the filter element both comprise an inner plate and an outer plate which are installed in a stacked manner, the inner plate is provided with first step holes, and the outer plate is provided with second step holes which are coaxially arranged one by one with the first step holes; The first step hole is sleeved on the corresponding inner filter type columnar cross flow filter element, the small hole end of the first step hole and the large hole end of the second step hole are both oriented toward the middle direction of the inner filter type columnar cross flow filter element, the inner diameter of the small hole end of the first step hole is larger than the outer diameter of the inner filter type columnar cross flow filter element, the inner diameter of the large hole end of the second step hole is smaller than the inner diameter of the large hole end of the first step hole, and the inner diameter of the small hole end of the second step hole is smaller than the outer diameter of the inner filter type columnar cross flow filter element; A sealing assembly is installed on the large hole channel wall of the first step hole, the sealing assembly is axially extruded between the inner step surface of the first step hole and the end surface of the outer plate and includes at least one sealing ring and at least one sealing ring pressure ring, the inner walls of these sealing rings are closely attached to the outer wall of the corresponding inner filter type columnar cross-flow filter element; The distance between the inner step surface of the second step hole in the first end positioning and mounting sealing structure of the filter element and the inner step surface of the second step hole in the second end positioning and mounting sealing structure of the filter element is greater than the length of the inner filter type columnar cross-flow filter element.

7. The cross-flow filtration device according to claim 6, characterized in that: A multi-channel inner filter type columnar cross-flow filter element inlet retaining ring is detachably installed in the small hole channels of each second step hole in the second end positioning and installing sealing structure of the filter element of each first cross-flow filter component and / or the first end positioning and installing sealing structure of the filter element of each second cross-flow filter component. The multi-channel inner filter type columnar cross-flow filter element inlet retaining ring comprises a retaining ring body, which is densely covered with liquid inlet through holes. These liquid inlet through holes are used to introduce the to-be-filtered liquid that flows through the small hole channels to the liquid inlet end of the multi-channel inner filter type columnar cross-flow filter element into the liquid inlet end of the multi-channel inner filter type columnar cross-flow filter element.

8. The cross-flow filtration device according to any one of claims 1 to 7, characterized in that: It includes a liquid inlet pipeline, which is connected to the main pipe of the liquid to be filtered and / or the main pipe of the concentrated liquid, and is used to provide a supply channel for the external liquid to be filtered; And / or, it includes a concentrate pipeline, which is connected to the main pipe of the liquid to be filtered and / or the main pipe of the concentrate to provide a channel for the discharge of the concentrate; And / or, comprising a clear liquid pipeline, the clear liquid pipeline is connected to the clear liquid output ports of each first cross-flow filter assembly and each second cross-flow filter assembly, and is used to provide an external discharge channel for the first clear liquid and the second clear liquid; And / or, when the main pipe for the liquid to be filtered and the main pipe for the concentrated liquid are arranged in parallel in the horizontal direction, each first cross-flow filter assembly is a vertical cross-flow filter assembly and is installed in parallel above the main pipe for the liquid to be filtered, the lower end of each first cross-flow filter assembly is the input end for the liquid to be filtered and the upper end is the output end for the concentrated liquid, each second cross-flow filter assembly is a vertical cross-flow filter assembly and is installed in parallel above the main pipe for the concentrated liquid, the upper end of each second cross-flow filter assembly is the input end for the liquid to be filtered and the lower end is the output end for the concentrated liquid, and each guide pipe is respectively connected between the upper end of the corresponding first cross-flow filter assembly and the upper end of the corresponding second cross-flow filter assembly, then each guide pipe is an inverted U-shaped pipe, and the top of each inverted U-shaped pipe is also connected to an exhaust pipeline.

9. A method for removing impurities and purifying a nickel sulfate solution, characterized in that: The method comprises the step of subjecting the nickel sulfate solution raw material obtained by smelting nickel ore to ultrafiltration treatment through a cross-flow filtration device as described in any one of claims 1 to 8.

10. Equipment for removing impurities and purifying nickel sulfate solution, characterized in that: It comprises a cross-flow filtration device as described in any one of claims 1 to 8, and the cross-flow filtration device is used for ultrafiltration treatment of a nickel sulfate solution raw material obtained by smelting nickel ore.

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