Multi-stage pipeline magnetic filter with high magnetic conductivity

Abstract

The invention relates to the technical field of high-temperature and high-pressure pregnant solution pipeline magnetic separation, in particular to a high-magnetic-conductivity multi-stage pipeline magnetic filter which comprises a magnetic filtering part and a magnetic separation part, the magnetic filtering part is composed of multi-stage magnetic capturing modules and a quick-release flushing opening, the multi-stage magnetic capturing modules are contained in an axial inner cavity of the magnetic filtering part, and at least two stages of the multi-stage magnetic capturing modules are arranged in series in the fluid direction; each stage of magnetic capture module comprises a high-permeability magnetic box and a non-magnetic screen arranged at the downstream of the high-permeability magnetic box; the second connecting flange is arranged at one end of the external sleeve and is connected with the teflon gasket, the secondary sealing ring and the third connecting flange through connecting bolts so as to detachably seal and fix the magnetic filtering part; and the annular cooling sleeve is arranged at the middle section of the outer wall of the outer sleeve. According to the invention, the fine particle capture rate is improved, and on-line flushing without stopping a pump and leakage prevention of a high-temperature gasket are realized.

Description

Technical Field

[0001] This invention relates to the field of magnetic separation technology for high-temperature and high-pressure precious liquid pipelines, and in particular to a multi-stage pipeline magnetic filter with high magnetic permeability. Background Technology

[0002] The gold desorption-electrolysis section uses a magnetically driven pump to achieve closed-loop circulation. The radial clearance between the pump's isolation sleeve and the inner magnetic rotor is ≤1mm. When ferromagnetic particles enter the pump chamber, they can tear through the isolation sleeve within 1–2 minutes, leading to high-temperature precious liquid splashing, production shutdown, and precious metal loss. Existing technologies generally use single-stage magnetic rods or grid-insertion magnetic separators, which have the following drawbacks: 1. Monotonous magnetic gradient, with a capture rate of <85% for 10–50µm fine particles; 2. The magnetic source is located downstream of the screen, requiring particles to penetrate the screen before capture, easily forming "bridging" at the screen openings, resulting in rapid pressure drop; 3. No redundant flow channels, requiring pump shutdown for flushing, interrupting continuous production; 4. The planar PTFE gasket fails to seal after high-temperature creep, with a leakage rate >1×10⁻³Pa·m³ / s. Therefore, the market urgently needs a magnetic filter with high capture rate, zero downtime, zero leakage, and in-situ upgrade and replacement capabilities.

[0003] Chinese patent application CN115627351B discloses a method for controlling the microstructure of hydrometallurgical solutions using magnetic confinement, belonging to the technical field of altering material structure using strong magnetic extreme environments. The method involves the hydrometallurgical solution being uniformly diverted through an adjustable magnetic field device composed of a uniform magnetic field and a gradient magnetic field in parallel, flowing in steady, turbulent, or rotating states. The spacing between the magnetic field poles and the residence time and circulation frequency of the solution between the poles are adjusted. Through asymmetric reciprocating magnetization, water cluster structures, ion pair structures, and ion cluster structures are confined, thereby directionally enhancing the migration rate of ions at the solid / liquid interface, selectively controlling the chemical reaction potential, reducing the Coulomb barrier of charge separation, and ultimately reducing energy consumption and side reactions in the hydrometallurgical process. This also alters the structure and type of chemical reaction products, obtaining chemical reaction products that cannot be prepared under conventional conditions. However, this method still does not solve the problems of low fine particle capture rate, the need to stop pumps for online flushing, and high-temperature gasket leakage during high-temperature precious liquid splashing, production shutdowns, and precious metal loss in hydrometallurgical processes. Summary of the Invention

[0004] Therefore, the present invention provides a multi-stage pipeline magnetic filter with high magnetic permeability to overcome the problems of low fine particle capture rate, need to stop pumps for online flushing, and leakage of high temperature gaskets in the prior art when high temperature precious liquid splashes, production stops, and precious metal loss during hydrometallurgical processes.

[0005] To achieve the above objectives, the present invention provides a multi-stage pipeline magnetic filter with high magnetic permeability, comprising: The magnetic filtration section consists of a multi-stage magnetic capture module and a quick-release flushing port. The multi-stage magnetic capture module is housed in the axial inner cavity of the magnetic filtration section and at least two stages are arranged in series along the fluid direction. Each stage of the magnetic capture module includes a high-permeability magnetic box and a non-magnetic screen disposed downstream of the high-permeability magnetic box. The outer sleeve is a straight pipe section with a third connecting flange and a fourth connecting flange at both ends, forming an axial inner cavity inside; The first connecting flange is located at one end of the magnetic filter section outside the outer sleeve; The second connecting flange is located at one end of the outer sleeve. It is connected to the PTFE gasket, the secondary sealing ring, and the third connecting flange by connecting bolts to detachably seal and fix the magnetic filter part. An annular cooling jacket is installed in the middle section of the outer wall of the outer sleeve. It is formed by fitting and welding a concentric annular jacket to reduce the wall temperature of the outer sleeve.

[0006] Furthermore, the high permeability magnetic box includes a shield made of a high permeability soft magnetic material and a permanent magnet encapsulated within the shield.

[0007] Furthermore, the high-permeability soft magnetic material is permalloy.

[0008] Furthermore, the non-magnetic screen 10122 is an austenitic stainless steel woven mesh.

[0009] Furthermore, the secondary sealing ring is a PTFE-coated metal elastic C-ring.

[0010] Furthermore, in the series-connected multi-stage magnetic capture modules, the magnetic energy product of the high-permeability magnetic box in the downstream magnetic capture module is greater than that of the high-permeability magnetic box in the upstream magnetic capture module.

[0011] Furthermore, the multi-stage magnetic capture module has at least three stages, and the permanent magnet of the high permeability magnetic box in at least one stage is a samarium cobalt permanent magnet, while the permanent magnet of the high permeability magnetic boxes in the remaining stages is a neodymium iron boron permanent magnet.

[0012] Furthermore, a filtration system includes at least two sets of high-permeability multi-stage in-line magnetic filters connected in parallel, and a three-way switching valve for switching fluid passages between the at least two sets of high-permeability multi-stage in-line magnetic filters.

[0013] Furthermore, each of the aforementioned high-permeability multi-stage pipeline magnetic filters is equipped with a differential pressure transmitter downstream for monitoring its pressure drop.

[0014] Furthermore, high-permeability multi-stage pipeline magnetic filters and filtration systems are applied in the iron removal and purification of precious liquids in the gold desorption electrolysis process.

[0015] Compared with existing technologies, the advantages of this invention are as follows: the multi-stage pipeline magnetic filter forms a progressive strong gradient magnetic field through multiple series-connected high-permeability magnetic boxes, achieving a single-pass capture rate of over 99.5% for ferromagnetic particles larger than 10μm, effectively protecting the downstream magnetically driven pump. The multi-stage pipeline magnetic filter, with its front-mounted magnetic boxes (each box located upstream of the screen), ensures that most ferromagnetic particles are adsorbed before contacting the screen, preventing rapid bridging and clogging at the screen openings, significantly slowing the rise in system pressure drop and extending the cleaning cycle. The flange assembly design allows the entire magnetic capture module to be disassembled, flushed, and reset within minutes, greatly reducing downtime. The optimized sealing structure, including double sealing rings, ensures long-term sealing reliability under high temperature and high pressure conditions of 180℃ and 1.0MPa, preventing leakage of precious liquids. The reverse flushing and parallel switching valve group design enables zero-downtime switching cleaning, meeting continuous production requirements. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the high-permeability multi-stage pipeline magnetic filter in this embodiment. Detailed Implementation

[0017] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0018] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0019] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate the direction or positional relationship, are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0020] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] Please see Figure 1 As shown, this is a structural schematic diagram of the high-permeability multi-stage pipeline magnetic filter of this embodiment. The multi-stage pipeline magnetic filter includes: The magnetic filtration section 1 consists of a multi-stage magnetic capture module and a quick-release flushing port 104. The multi-stage magnetic capture module is housed in the axial inner cavity of the magnetic filtration section 1 and at least two stages are arranged in series along the fluid direction. Each stage of the magnetic capture module includes a high permeability magnetic box and a non-magnetic screen disposed downstream of the high permeability magnetic box. The outer sleeve 2 is a straight pipe section with a third connecting flange 6 and a fourth connecting flange 8 at both ends, and forms an axial inner cavity inside; The first connecting flange 3 is located at one end of the magnetic filter section 1 outside the outer sleeve 2; The second connecting flange 4 is located at one end of the outer sleeve 2. It is connected to the PTFE gasket 5, the secondary sealing ring (not shown in the figure), and the third connecting flange 6 by connecting bolts, so as to detachably seal and fix the magnetic filter part 1. An annular cooling jacket 7 is located in the middle section of the outer wall of the outer sleeve 2. It is formed by fitting and welding a concentric annular jacket to reduce the wall temperature of the outer sleeve 2.

[0022] Specifically, the multi-stage pipeline magnetic filter is used for magnetic filtration of high-temperature, high-pressure precious liquids in hydrometallurgical processes. By incorporating multi-stage magnetic capture modules and quick-release flushing ports, it improves the capture rate of fine particles, enabling online flushing without pump interruption. High-temperature gaskets prevent leakage. The multi-stage pipeline magnetic filter uses multiple series-connected high-permeability magnetic boxes to form a progressive, strong gradient magnetic field, achieving a single-pass capture rate of over 99.5% for ferromagnetic particles larger than 10μm, effectively protecting the downstream magnetically driven pump. The multi-stage pipeline magnetic filter's design, with each magnetic box positioned upstream of the screen, ensures that most ferromagnetic particles are effectively captured upon contact. The particles are adsorbed before they reach the screen, preventing rapid bridging and clogging at the screen openings, significantly slowing down the rate of increase in system pressure drop, and extending the cleaning cycle. The multi-stage pipeline magnetic filter, through its flange assembly design, allows the entire magnetic capture module to be disassembled, flushed, and reset within minutes, greatly reducing downtime. The multi-stage pipeline magnetic filter, through its optimized sealing structure including double sealing rings, ensures long-term sealing reliability under high temperature and high pressure conditions of 180℃ and 1.0MPa, preventing leakage of precious liquids. The multi-stage pipeline magnetic filter, through its reverse flushing and parallel switching valve group design, achieves zero-downtime switching cleaning, meeting the needs of continuous production.

[0023] Specifically, the direction from the second connecting flange 4 to the third connecting flange 6 is taken as the fluid direction. The high-temperature precious liquid flows in from the fluid direction and passes sequentially through the high permeability magnetic boxes in each level of the magnetic capture module and the non-magnetic screen set downstream of the high permeability magnetic boxes. The high permeability magnetic boxes in each level of the magnetic capture module capture ferromagnetic particles in the high-temperature precious liquid, and then the non-magnetic screens in each level of the magnetic capture module intercept the non-magnetic particles in the high-temperature precious liquid. When the differential pressure transmitter detects that the pressure drop is greater than the preset pressure drop value, the control system prompts the magnetic filter to be maintained, closes the pipeline isolation valve of the magnetic filter, opens the quick-release flushing port 104 for reverse flushing, loosens the connecting bolts of the second connecting flange 4 and the third connecting flange 6, pulls out the magnetic filter part 1, rinses it with demineralized water and then resets it. The total downtime is ≤5min.

[0024] Specifically, the high-temperature precious liquid refers to the circulating liquid in the gold desorption-electrolysis circuit; the high-permeability magnetic box refers to a closed cuboid composed of a 1mm thick permalloy shield and a permanent magnet, with an apparent permeability μr ≥ 80000, used to form a gradient magnetic field ≥ 0.5T within a 3mm radius outside the high-permeability magnetic box; the non-magnetic screen refers to a woven mesh made of 316L stainless steel. The parameters of the non-magnetic screen are not limited, but can be set to a aperture of 150µm, a wire diameter of 80µm, and a relative permeability μr ≈ 1, used to intercept non-magnetic particles ≥ 150µm. In this embodiment, the differential pressure transmitter refers to an intelligent differential pressure transmitter with a range of 0– The pressure drop is 0.2 MPa, with an accuracy of ±0.075%FS and a response time of ≤200ms. It is used to measure the inlet-outlet pressure difference of the magnetic filter section in real time. The pressure drop refers to the steady-state pressure difference between the inlet and outlet of the multi-stage pipeline magnetic filter. In this embodiment, the preset pressure drop value is set to 0.05 MPa. The control system refers to the local DCS logic of the multi-stage pipeline magnetic filter. The pipeline isolation valve refers to the 304 stainless steel ball valve installed at the inlet and outlet of the multi-stage pipeline magnetic filter. It is used to cut off the process fluid during maintenance. In this embodiment, 0.3 MPa demineralized water is connected during backflushing, and the backflushing time is 2 minutes to ensure that the iron filings removal rate is ≥99%.

[0025] Specifically, there are 4 sets of connecting bolts, evenly distributed at 90° around the circumference of the second connecting flange 4 and the third connecting flange 6. They can be loosened by hand by 1 / 4 turn, and the disassembly time is ≤30 seconds.

[0026] Specifically, the annular cooling jacket is circulated with 25°C demineralized water to reduce the wall temperature of the outer sleeve 2 to below 80°C.

[0027] Specifically, the quick-release flushing port 104 is located at the tail end of the multi-stage magnetic capture module along the fluid direction, and is used to connect the flushing pipeline to perform reverse flushing of the multi-stage magnetic capture module. The reverse flushing refers to flushing in a direction that is horizontally opposite to the fluid direction.

[0028] Specifically, the high permeability magnetic box includes a shield made of a high permeability soft magnetic material and a permanent magnet encapsulated within the shield.

[0029] Specifically, the high-permeability soft magnetic material is permalloy.

[0030] Specifically, the non-magnetic screen 10122 is an austenitic stainless steel woven mesh.

[0031] Specifically, the non-magnetic screen is laid flat downstream of the high-permeability magnetic box and is clamped to the steel reinforcement frame with pipe clamps around its perimeter, and can be disassembled and replaced individually.

[0032] Specifically, the secondary sealing ring is a PTFE-coated metal elastic C-ring.

[0033] Specifically, in a series-connected multi-stage magnetic capture module, the magnetic energy product of the high-permeability magnetic box in the downstream magnetic capture module is greater than that of the high-permeability magnetic box in the upstream magnetic capture module. Example

[0034] The outer sleeve 2 is a section of Φ57×4mm seamless 304 stainless steel pipe with a smooth cylindrical channel in its axial cavity. Both ends of the outer sleeve 2 are welded with PL-RF1650 flanges conforming to HG / T20592 standard, serving as the first connecting flange 3 and the fourth connecting flange 8 for connection to the process piping. The magnetic filter section 1 is inserted entirely into the axial cavity of the outer sleeve 2. The magnetic filter section 1 is equipped with two-stage series magnetic capture modules, wherein: The first-stage magnetic capture module 101 consists of a high-permeability magnetic box 1011 and a first-stage filter section 1012. The high-permeability magnetic box 1011 is a sealed square box welded from a 1mm thick permalloy plate, and encapsulates an N52 grade neodymium iron boron permanent magnet array inside, so that its frontal surface generates a magnetic flux density of not less than 0.5T at a distance of 3mm. The first-stage filter section 1012 consists of a first-stage steel frame 10121 and a first-stage non-magnetic screen 10122. The second-stage magnetic capture module 102 has a similar structure to the first-stage magnetic capture module 101, including a secondary high-permeability magnetic box 1021 and a secondary filtration section 1022. The secondary filtration section 1022 is equipped with a secondary steel reinforcement frame and a secondary non-magnetic screen. The magnetic energy product of the permanent magnet in the secondary high-permeability magnetic box 1021 is greater than that of the permanent magnet in the primary high-permeability magnetic box 1011, in order to compensate for the magnetic field attenuation caused by the adsorption of some ferromagnetic particles in the high-temperature precious liquid by the first-stage magnetic capture module 101, and to ensure that there is still a sufficiently strong capture magnetic field at the entrance of the second-stage magnetic capture module 102. The secondary non-magnetic screen is the same as the primary non-magnetic screen 10122. The first connecting flange 3 is located at one end of the magnetic filter section 1 outside the outer sleeve 2; The second connecting flange 4 is located at one end of the outer sleeve 2. It is connected to the PTFE gasket 5, the secondary sealing ring (not shown in the figure), and the third connecting flange 6 by connecting bolts, so as to detachably seal and fix the magnetic filter part 1. The quick-release flushing port 104 is located at the tail of the second-stage magnetic capture module 102 and is used to connect the flushing pipeline to perform reverse flushing of the first-stage magnetic capture module 101 and the second-stage magnetic capture module 102.

[0035] Specifically, the 304 stainless steel refers to austenitic stainless steel conforming to the unified digital code S30408 ​​of GB / T 20878-2007; the 3HG / T20592 standard refers to the chemical industry flange standard HG / T 20592-2009; the 3PL-RF1650 flange refers to the abbreviation of PL-RF PN16 DN50 in the HG / T 20592 standard, with an outer diameter of Φ165 mm, a bolt hole center circle of Φ125 mm, a thickness of 20 mm, a sealing surface protrusion height of 2 mm, and 8×M16 bolts evenly distributed; and the N52 grade neodymium iron boron permanent magnet array refers to sintered neodymium iron boron magnets of grade N52 according to GB / T 13560-2017. Example

[0036] Based on Example 1, two enhancements were made to adapt to long-term high-temperature operation, namely: An annular cooling jacket 7 is located in the middle section of the outer wall of the outer sleeve 2. It is formed by fitting and welding a concentric annular jacket to reduce the wall temperature of the outer sleeve 2. The annular cooling jacket 7 is provided with a cooling medium inlet and outlet. By continuously introducing a cooling medium, such as 25°C demineralized water, into the annular cooling jacket 7, the wall temperature of the outer sleeve 2 is reduced from the process fluid temperature of 180°C to below 80°C. This ensures that the working environment temperature of the first-stage high permeability magnetic box 1011 and the second-stage high permeability magnetic box 1021 is much lower than their Curie temperature, effectively preventing high-temperature demagnetization and ensuring the long-term stability of the magnetic field. The third-stage magnetic capture module 103 is added between the original first-stage magnetic capture module 101 and the second-stage magnetic capture module 102. The third-stage magnetic capture module 103's three-stage high-permeability magnetic box 1031 uses a high-temperature resistant SmCo samarium cobalt permanent magnet, whose magnetic properties remain good even at a high temperature of 180°C. Its three-stage filtration section 1032 is equipped with a three-stage steel reinforcement frame and a three-stage non-magnetic screen. The aperture of the three-stage non-magnetic screen is set to be smaller than the aperture of the first-stage non-magnetic screen 10122 and the aperture of the second-stage non-magnetic screen to improve the interception ability of smaller ferromagnetic particles.

[0037] Specifically, the SmCo samarium cobalt permanent magnet refers to the SmCo30 type sintered samarium cobalt magnet used in the third-stage magnetic capture module 1031. Example

[0038] Two sets of high permeability multi-stage pipeline magnetic filters as described in Example 1 or Example 2 are installed in parallel. A three-way switching valve, such as an L-type three-way ball valve, is installed on the inlet and outlet main pipes of the parallel pipeline. By operating the three-way switching valve, the high-temperature precious liquid is switched from the working high permeability multi-stage pipeline magnetic filter to another cleaned and ready-to-use high permeability multi-stage pipeline magnetic filter. Each high-permeability multi-stage pipeline magnetic filter is equipped with a differential pressure transmitter downstream to monitor the pressure drop of each filter in real time. When the pressure drop of the operating high-permeability multi-stage pipeline magnetic filter reaches the preset value, the control system prompts for magnetic filter maintenance and controls the three-way switching valve to switch to another cleaned and standby high-permeability multi-stage pipeline magnetic filter. After switching, the previously stopped high-permeability multi-stage pipeline magnetic filter is flushed and maintained online or offline without shutting down the entire process system.

[0039] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A multi-stage pipeline magnetic filter with high magnetic permeability, characterized in that, include: The magnetic filtration section consists of a multi-stage magnetic capture module and a quick-release flushing port. The multi-stage magnetic capture module is housed in the axial inner cavity of the magnetic filtration section and at least two stages are arranged in series along the fluid direction. Each stage of the magnetic capture module includes a high-permeability magnetic box and a non-magnetic screen disposed downstream of the high-permeability magnetic box. The outer sleeve is a straight pipe section with a third connecting flange and a fourth connecting flange at both ends, forming an axial inner cavity inside; The first connecting flange is located at one end of the magnetic filter section outside the outer sleeve; The second connecting flange is located at one end of the outer sleeve. It is connected to the PTFE gasket, the secondary sealing ring, and the third connecting flange by connecting bolts to detachably seal and fix the magnetic filter part. An annular cooling jacket is installed in the middle section of the outer wall of the outer sleeve. It is formed by fitting and welding a concentric annular jacket to reduce the wall temperature of the outer sleeve.

2. The high permeability multi-stage pipeline magnetic filter according to claim 1, characterized in that, The high permeability magnetic box includes a shield made of a high permeability soft magnetic material and a permanent magnet encapsulated within the shield.

3. The high permeability multi-stage pipeline magnetic filter according to claim 2, characterized in that, The high-permeability soft magnetic material is permalloy.

4. The high permeability multi-stage pipeline magnetic filter according to claim 1, characterized in that, The non-magnetic screen 10122 is an austenitic stainless steel woven mesh.

5. The high permeability multi-stage pipeline magnetic filter according to claim 1, characterized in that, The secondary sealing ring is a PTFE-coated metal elastic C-ring.

6. The high permeability multi-stage pipeline magnetic filter according to claim 1, characterized in that, In a series-connected multi-stage magnetic capture module, the magnetic energy product of the high-permeability magnetic cell in the downstream magnetic capture module is greater than that of the high-permeability magnetic cell in the upstream magnetic capture module.

7. The high permeability multi-stage pipeline magnetic filter according to claim 6, characterized in that, The multi-stage magnetic capture module has at least three stages, and the permanent magnet of the high permeability magnetic box of at least one stage is a samarium cobalt permanent magnet, while the permanent magnet of the high permeability magnetic boxes of the other stages is a neodymium iron boron permanent magnet.

8. A filtration system, characterized in that, It includes at least two sets of high-permeability multi-stage pipeline magnetic filters as described in any one of claims 1-7 connected in parallel, and a three-way switching valve for switching the fluid passage between the at least two sets of high-permeability multi-stage pipeline magnetic filters.

9. The filtration system according to claim 8, characterized in that, Each of these high-permeability multi-stage pipeline magnetic filters is equipped with a differential pressure transmitter downstream for monitoring its pressure drop.

10. The high-permeability multi-stage pipeline magnetic filter according to any one of claims 1-7 or the filtration system according to claims 8-9 is used in the iron removal and purification of precious liquids in the gold desorption electrolysis process.

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