Magnetic material recovery device and magnetic material recovery method

Abstract

To propose a magnetic material recovery device which can inhibit accumulation of a magnetic material in a tank and recover the magnetic material in a liquid efficiently, and to propose a magnetic material recovery method.SOLUTION: A magnetic material recovery device 4 includes: a storage tank 41 in which a liquid including a magnetic material is stored; a drum 42 which is provided so as to be rotatable around a lateral axis while partially immersed in the liquid; and a scraper 43 which scrapes the magnetic material adhering to an outer peripheral surface of the drum 42. A magnet 46 which generates a magnetic force on the outer peripheral surface of the drum 42 is provided in the drum 42. The storage tank 41 exhibits a funnel-shape in which a plane shape becomes smaller toward the lower side, and a liquid sending pipe which supplies the liquid to the storage tank 41 is connected to a bottom part of the storage tank 41.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a magnetic material recovery device and magnetic material recovery. [Background technology]

[0002] The turbidity contained in muddy water and turbid water derived from construction soil must be properly treated by coagulation and sedimentation, etc. In addition, if the muddy water or turbid water contains heavy metals, the heavy metals must be removed. A method has been proposed in which a magnetic material such as iron powder is used as a sedimentation promoter in the coagulation and sedimentation treatment of suspended solids.In addition, based on the knowledge that magnetic materials such as iron powder adsorb heavy metals dissolved in liquid, a method has been proposed for removing heavy metals in which heavy metals are adsorbed by magnetic materials and then separated by magnetic separation or centrifugal separation. Here, magnetic separation can be performed using a method that uses a superconducting magnet or a method that uses a permanent magnet. The method using permanent magnets (magnetic separator) has the advantage of being more compact and using less energy than the method using superconducting magnets. A magnetic separator is a device that includes a storage tank (tank section), a magnetic core, an outer cylinder that covers the outer circumference of the magnetic core, a roller that squeezes out water from the magnetic material attached to the outer cylinder, and a scraper that removes the magnetic material from which the water has been squeezed by the roller from the outer cylinder, and is generally used to remove metals (magnetic materials) from wastewater discharged from cutting factories, etc.

[0003] Meanwhile, in the construction industry, magnetic separators and other magnetic separators are used to add magnetic materials to muddy water and the like as useful materials, and to separate only the magnetic materials from the muddy water for repeated use (see, for example, Patent Document 1). In this case, compared to the conventional method of using a magnetic separator, a large amount of magnetic materials is contained in the liquid, and the magnetic materials that cannot be attached to the magnet core are retained in the tank section in front of the magnet core, which may cause a bias in the distribution of the magnetic materials attached to the magnet core, resulting in problems such as poor dewatering and variations in magnetic separation. In addition, the magnetic materials with a high specific gravity settle and accumulate in the tank section, reducing the effective volume of the tank section, and the inflowing treated water may overflow outside the tank. Therefore, Patent Document 2 discloses a method for generating a water flow inside a tank in order to reduce the accumulation of magnetic material. In addition, since tanks are generally box-shaped (rectangular parallelepiped), even if a water flow is generated in the tank, dead water areas will be generated, for example in the corners of the tank, and there is a risk that magnetic material will accumulate in these dead water areas. There is also a risk that the nozzle for generating the water flow will be clogged with magnetic material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5746407 [Patent Document 2] Patent Publication No. 2021-194552 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to propose a magnetic material recovery device and a magnetic material recovery method that suppress the retention of magnetic materials inside a tank and enable efficient recovery of magnetic materials from liquid. [Means for solving the problem]

[0006] In order to solve the above problems, the magnetic material recovery device of the present invention includes a storage tank for storing a liquid containing magnetic material, a drum that is rotatable about a horizontal axis while being partially immersed in the liquid, and a scraper for scraping off the magnetic material adhering to the outer circumferential surface of the drum. A magnet is provided inside the drum for generating a magnetic force on the outer circumferential surface of the drum. The storage tank is funnel-shaped with a planar shape that becomes smaller toward the bottom, and a liquid supply pipe for supplying the liquid to the storage tank is connected to its bottom. According to this magnetic material recovery device, the bottom of the funnel-shaped storage tank does not have any corners, so magnetic materials are less likely to accumulate at the bottom of the storage tank. In addition, because liquid is supplied to the funnel-shaped storage tank from the bottom, the liquid in the storage tank is efficiently stirred. Because an upward flow is formed by the supply of liquid, magnetic materials that move with the flow of liquid are guided to the drum side and separated from the liquid by magnetic force. Magnetic materials that adhere to the drum are scraped off by a scraper, so the magnetic materials can be efficiently separated.

[0007] If a water sprinkling means is provided for sprinkling water onto the upper surface of the scraper, the magnetic material scraped off the drum can be prevented from remaining on the scraper, allowing the magnetic material to be recovered more efficiently. Furthermore, if a drain pipe for draining the liquid is connected to the liquid supply pipe via an opening / closing means, even if sediments accumulate at the bottom of the storage tank, the sediments can be removed by opening the drain pipe via the opening / closing means.

[0008] The magnetic material recovery method of the present invention recovers magnetic materials from a liquid using the magnetic material recovery device, and includes a liquid delivery step of supplying the liquid to the storage tank through the liquid delivery pipe, and a separation step of separating the magnetic materials from the liquid. In the separation step, the drum is rotated in contact with the liquid, so that the magnetic materials adhere to the outer circumferential surface of the drum by the magnetic force generated on the outer circumferential surface of the drum, and the magnetic materials adhered to the drum are removed by the scraper. The method may further include a cleaning step of washing away the magnetic material adhering to the scraper by spraying water on an upper surface of the scraper. According to this magnetic material recovery method, magnetic materials that have been added to a liquid for the purpose of purification treatment or the like can be efficiently recovered from the liquid. Effect of the Invention

[0009] According to the magnetic material recovery device and magnetic material recovery method of the present invention, it is possible to suppress the retention of magnetic materials inside a tank and efficiently recover the magnetic materials from a liquid. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a purification device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the magnetic material recovery device. [Diagram 3] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The following is a description of the muddy water generated during muddy shield construction in ground containing naturally occurring heavy metals. D This section explains how to remove heavy metals dissolved in muddy water W. D A purification device 1 is used to remove heavy metals from the water. Fig. 1 shows the purification device 1 of this embodiment. Note that heavy metals to be purified are not limited, and examples thereof include arsenic, cadmium, hexavalent chromium, mercury, selenium, lead, fluorine, and boron. As shown in FIG. 1, the purification device 1 includes a muddy water storage tank 2, a mixing tank 3, a magnetic material recovery device 4, and a treated water storage tank 5.

[0012] Muddy water storage tank 2 is muddy water W D The muddy water storage tank 2 is connected to the mixing tank 3 via a first transport pipe 61. The first transport pipe 61 is a tank for storing the muddy water W DThe pipeline is provided with a liquid pump P1 for transporting the muddy water W stored in the muddy water storage tank 2. D is supplied to the mixing tank 3 through the first transport pipe 61 by the liquid supply pump P1. The liquid supply pump P1 may be automatically controlled. DF Depending on the change in the amount of muddy water, muddy water W is automatically transferred from the muddy water storage tank 2 to the mixing tank 3. D Alternatively, the muddy water W may be fed from the muddy water storage tank 2 to the mixing tank 3 at a preset flow rate. D The muddy water W from the muddy water storage tank 2 to the mixing tank 3 may be continuously sent. D The muddy water W may be sent periodically. D If necessary, a neutralizing agent may be mixed into the muddy water W before being supplied to the mixing tank 3. When a neutralizing agent is mixed, the timing of adding the neutralizing agent is not limited. D The neutralizing agent may be added to the mixing tank 3 or to the aqueous solution.

[0013] Mixing tank 3 contains muddy water W D This tank mixes and stirs the muddy water W with iron powder (magnetic material) for a certain retention time. D By mixing with iron powder, muddy water W D The heavy metals contained in the muddy water W are adsorbed by the iron powder. The iron powder of this embodiment is provided with a function of adsorbing heavy metals. Note that the magnetic material used for adsorbing heavy metals is not limited to iron powder. The mixing tank 3 has an agitator (not shown), and the muddy water W introduced into the mixing tank 3 is mixed with the iron powder. D and the iron powder are stirred. A second transport pipe 62 (transport pipe) leading to the magnetic material recovery device 4 is connected to the mixing tank 3. The configuration of the stirrer is not limited. For example, the number of stirrers provided in the mixing tank 3 is not limited, and may be determined appropriately.

[0014] The second transport pipe 62 transports the muddy water W D and iron powder. DF This is a pipeline for transporting mixed muddy water W DFis pumped to the magnetic material recovery device 4 via the second transport pipe 62 by the liquid feed pump P2 provided in the second transport pipe 62.

[0015] The magnetic material recovery device 4 recovers the mixed muddy water W supplied from the mixing tank 3. DF The iron powder is separated from the magnetic material by magnetic force. Fig. 2 shows the magnetic material recovery device 4 of this embodiment. As shown in Fig. 2, the magnetic material recovery device 4 includes a storage tank 41, a drum 42, a scraper 43, a water sprinkling means 44, and a return means 45 (see Fig. 1).

[0016] The storage tank 41 contains a mixed muddy water W containing a magnetic material. DF The storage tank 41 has a rectangular shape in a plan view, and is divided into a first storage section 411 and a second storage section 412 by a partition wall 413. The first storage section 411 has a funnel shape (an inverted truncated pyramid shape in this embodiment) whose planar shape becomes smaller toward the bottom. A second transport pipe 62 (liquid sending pipe) extending from the mixing tank 3 is connected to the bottom of the first storage section 411 (the lower end in this embodiment). That is, the mixed muddy water W transported via the second transport pipe 62 is DF is supplied from the bottom to the storage tank 41 (first storage section 411). A drain pipe 64 is connected to the second transport pipe 62 via an opening / closing means (switching valve 65).

[0017] The upper end of the partition wall 413 is lower than the side wall (wall surrounding the outside of the first storage section 411 and the second storage section 412) 414 of the storage tank 41. A guide plate 415 having an arc-shaped cross section that protrudes toward the second storage section 412 is formed at the upper end of the partition wall 413. The guide plate 415 protrudes from the partition wall 413 below the drum 42 and is provided along the drum 42. The mixed muddy water W in the first storage section 411 that has overflowed the partition wall 413 DF While in contact with drum 42 , the liquid passes over guide plate 415 and flows into second reservoir 412 .

[0018] The second storage section 412 contains treated water W from which iron powder P (magnetic material) has been removed by the drum 42. SThe second storage section 412 is connected to a bottom surface of the third transport pipe 63. As shown in FIG. 1, the third transport pipe 63 is connected to the bottom surface of the second storage section 412. S to the treated water storage tank 5. The bottom surface of the second storage section 412 in this embodiment is flat, but may be inclined so as to become lower toward the connection portion of the third transport pipe 63.

[0019] As shown in FIG. 2, the drum (outer cylinder) 42 is provided on a guide plate 415, and the mixed muddy water W DF The drum 42 is rotatably mounted about a horizontal axis (horizontal axis in this embodiment) with a portion of the drum 42 immersed in the water. The drum 42 has a cylindrical shape. A magnet (magnetic core) 46 that generates a magnetic force on the outer circumferential surface of the drum 42 is provided inside the drum 42. A roller 47 that squeezes out moisture from the iron powder adhering to the drum 42 by the magnetic force is also attached to the drum 42.

[0020] The scraper 43 scrapes off iron powder adhering to the outer peripheral surface of the drum 42. One end of the scraper 43 is attached to the drum 42, and the other end of the scraper 43 is connected to the return means 45. The scraper 43 is made of a non-magnetic material. One end of the scraper 43 is in contact with the drum 42 or is attached to the drum 42 with a small gap therebetween. A cushioning material may be provided at one end of the scraper 43 as necessary.

[0021] A water sprinkling means 44 is provided above the scraper 43. FIG. 3 shows the water sprinkling means 44. As shown in FIG. 3, the water sprinkling means 44 of this embodiment is a pipe that is horizontally installed above the scraper 43 along the width direction of the scraper 43, and sprinkles water toward the upper surface of the scraper 43. The water sprinkling means 44 is provided with a plurality of spray nozzles, and a water supply pipe is connected to the base end. Water supplied through the water supply pipe flows out from the scraper nozzle, and the water is sprinkled on the upper surface of the scraper 43. The configuration of the water sprinkling means 44 is not limited. The water sprinkling means 44 of this embodiment can move up and down along the upper surface of the scraper 43, and can sprinkle water over the entire upper surface of the scraper 43.

[0022] As shown in Fig. 1, the returning means 45 is interposed between the scraper 43 and the mixing tank 3. The returning means 45 returns the iron powder scraped off by the scraper 43 to the mixing tank 3. The returning means 45 in this embodiment is constituted by a so-called screw feeder. The configuration of the returning means 45 is not limited, and it may be, for example, a belt conveyor. In addition, when the magnetic material recovery device 4 is disposed above the mixing tank 3 and the iron powder scraped off by the scraper 43 falls directly into the mixing tank 3, the returning means 45 may be omitted.

[0023] The treated water storage tank 5 stores the treated water W discharged from the magnetic material recovery device 4. S In this embodiment, the treated water storage tank 5 is disposed at a lower position than the magnetic material recovery device 4. The treated water W discharged from the magnetic material recovery device 4 is stored in the treated water storage tank 5. S The treated water W is sent to the treated water storage tank 5 by gravity flow through the third transport pipe 63. If the treated water storage tank 5 is not located at a lower position than the magnetic material recovery device 4, the treated water W is sent to the treated water storage tank 5 by gravity flow through the third transport pipe 63. S can be pumped out.

[0024] In the purification method (magnetic material recovery method) using the purification device 1, first, the muddy water W supplied from the muddy water storage tank 2 is D The muddy water W and the iron powder are thoroughly mixed in the mixing tank 3.D (Mixed mud water W DF The heavy metals contained in the muddy water W supplied to the mixing tank 3 are adsorbed onto the iron powder (adsorption process). D If necessary, a neutralizing agent is added.

[0025] Next, Muddy Water W D and iron powder mixed muddy water W DF The mixed muddy water W is sent from the mixing tank 3 to the magnetic material recovery device 4 through the second transport pipe 62 (sending step). DF The sending of the mixed muddy water W from the mixing tank 3 to the magnetic material recovery device 4 may be performed periodically at a predetermined time, or may be performed continuously according to the processing capacity of the magnetic material recovery device 4. DF The liquid transfer may be automatically controlled according to the processing capacity of the magnetic material recovery device 4, or may be performed manually.

[0026] Next, the mixed muddy water W DF The magnetic material is separated from the mixture (separation step). The mixed muddy water W sent through the second transport pipe 62 DF The mixed muddy water W is supplied to the first storage section 411 (storage tank 41). DF Since the mixed muddy water W is supplied from the bottom of the first storage section 411, even if iron powder settles in the first storage section 411, the mixed muddy water W supplied from below DF The iron powder does not remain because it is stirred by the The mixed muddy water W supplied to the first storage section 411 DF The muddy water W that overflows the partition wall 413 passes over the guide plate 415 and flows into the second reservoir 412. DF The magnetic body in the drum 42 adheres iron powder to the outer circumferential surface of the drum 42 due to the magnetic force generated on the outer circumferential surface of the drum 42, and the mixed muddy water W DF Mixed muddy water W DF Treated water W that has been rendered harmless by separating iron particles from S The mixed muddy water W flows down through the third transport pipe 63 into the treated water storage tank 5. On the other hand, the mixed muddy water W DFThe iron powder separated from the scraper 43 is removed by the scraper 43 and returned to the mixing tank 3 via the return means 45. The iron powder adhering to the scraper 43 is washed away by spraying water on the upper surface of the scraper 43 by the water spray means 44 (cleaning step), and is returned to the mixing tank via the return means 45. If the adsorption performance of the iron powder is impaired, it is discharged outside the purification device 1 without being returned to the mixing tank 3.

[0027] In addition, if sediments accumulate at the bottom of the storage tank 41, the switching valve 65 closes the second transport pipe 62 and opens the drain pipe 64, thereby stopping the flow of liquid from the second transport pipe 62, draining the liquid from the bottom of the storage tank 41, and removing the sediments (sediment removal process).

[0028] According to the purification device 1 (magnetic body recovery device 4) of this embodiment, heavy metals contained in the liquid can be efficiently removed. In addition, since first reservoir 411 of reservoir 41 has a funnel shape, the magnetic material is less likely to accumulate at the bottom. By supplying the liquid to first reservoir 11 from the bottom, the liquid in reservoir 41 is efficiently agitated, making it more difficult for magnetic material to accumulate at the bottom. In addition, as liquid is supplied to first storage section 11, an upward flow is formed in first storage section 411, and the magnetic body that moves with the flow of the liquid is guided toward drum 42 and separated from the liquid by magnetic force. The magnetic material adhering to the drum 42 is scraped off by the scraper 43, so that the magnetic material can be separated efficiently. In addition, since the scraper 43 is provided with a water spraying means 44 for spraying water onto the upper surface of the scraper 43, the magnetic material scraped off from the drum 42 can be prevented from remaining on the scraper 43, and the magnetic material can be recovered more efficiently. In addition, since a drain pipe 64 is connected to the liquid delivery pipe, even if sediments accumulate at the bottom of the first storage section 411, the sediments can be removed by opening the drain pipe 64 using the opening / closing means.

[0029] Although an embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and each of the above-described components can be appropriately modified without departing from the spirit of the present invention. In the above embodiment, a purification process is performed on muddy water containing heavy metals generated during muddy shield construction work. However, the construction work for which the magnetic material recovery device 4 can be used is not limited to shield construction work. For example, the device may be used to recover magnetic materials used in the purification process of muddy water discharged during civil engineering work work. In addition, there is no limitation on the range of movement of the water sprinkling means 44. In addition, the water sprinkling means 44 does not necessarily need to be movable, and may be fixed to a position above the scraper 43 where water can be sprinkled. In the above embodiment, the switching valve 65 is used to switch between supply of muddy water through the liquid supply pipe and drainage through the drain pipe 64, but it is not necessary to use the switching valve 65. For example, the drain pipe 64 may be connected to the second transport pipe 62 by an opening and closing means, and the supply and drainage of muddy water may be switched by opening and closing the connection part of the drain pipe 64 by the opening and closing means. In this case, a check valve may be provided in the liquid supply pipe to prevent the drainage from flowing back into the mixing tank 3 during drainage. [Explanation of symbols]

[0030] 1 Purification equipment 2 Muddy water storage tank 3 Mixing tank 4. Magnetic material recovery device 41 Reservoir 411 First Reservoir 412 Second Reservoir 413 Partition Wall 414 Side wall 415 Guidance plate 42 Drums 43 Scraper 44 Watering means 45 Return Method 46 Magnet 47 Roller 5 Treated water storage tank 61 First transport pipe 62 Second transport pipe (liquid delivery pipe) 63 Third transport pipe 64 Drain pipe 65 Switching valve (opening / closing means) W D muddy water W DF mixed mud water W S Treated Water

Claims

1. a storage tank for storing a liquid containing a magnetic material; a drum rotatably mounted about a horizontal axis while being partially immersed in the liquid; A magnetic material recovery device comprising: a scraper that scrapes off the magnetic material adhering to the outer peripheral surface of the drum, A magnet is provided inside the drum to generate a magnetic force on the outer circumferential surface of the drum, The storage tank has a funnel shape whose planar shape becomes smaller toward the bottom, A magnetic material recovery device, characterized in that a liquid supply pipe for supplying the liquid to the storage tank is connected to a bottom of the storage tank.

2. 2. The magnetic material recovery device according to claim 1, further comprising a water sprinkler for sprinkling water onto an upper surface of the scraper.

3. 2. The magnetic material recovery device according to claim 1, wherein a drain pipe for draining the liquid is connected to the liquid supply pipe via an opening and closing means.

4. A magnetic material recovery method for recovering magnetic materials from a liquid by using the magnetic material recovery device according to any one of claims 1 to 3, comprising the steps of: a liquid sending step of supplying the liquid to the storage tank through the liquid sending pipe; and a separation step of separating the magnetic body from the liquid. A magnetic material recovery method characterized in that, in the separation process, a magnetic material adheres to the outer peripheral surface of the drum by a magnetic force generated on the outer peripheral surface of the drum by rotating the drum while in contact with the liquid, and the magnetic material adhered to the drum is removed by the scraper.

5. 5. The magnetic material recovery method according to claim 4, further comprising a washing step of washing away the magnetic material adhering to the scraper by spraying water on an upper surface of the scraper.

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