JPH10192731A - Magnetic separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve magnetic powder recovery efficiency of separated sludge by passing separated sludge which magnetic aggregate is washed by backwashing to form through a device having a magnetic separation part to recover the greater part of magnetic powder before adding a high molecular agent to the residual sludge to dehydrate it by a centrifuge. SOLUTION: From pretreated water which aggregate or the like is added to raw water from a chemical adjusting device 7 and is agitated in an agitation tank 9 to form, magnetic aggregate is separated and seized by a magnetic separator 30, and the aggregate is backwashed in a prescribed cycle to store washing water containing the magnetic aggregate in a backwash treating water tank 29. The washing water is then led to a magnetic powder recovery device 31 to decompose the magnetic aggregate by an agitating device 31a. After that, magnetic powder is separated and recovered by a magnetic powder recovering magnetic separator 31b, and the recovered magnetic powder is returned to the chemical adjusting device 7 to reuse it. Aggregate or the like is fed again from a chemical adjusting device 31d to sludge of the washing water from which magnetic powder has been separated and removed to reflocculate it in a mixing tank 31c before it is dehydrated by a centrifuge 31e to recover the residual magnetic powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a purification device,
In particular, the present invention relates to a structure of a purification device for separating and dewatering magnetic powder in sludge separated at high speed by magnetic separation.

[0002]

2. Description of the Related Art As a conventional magnetic separation device, for example,
As a magnetic field generator for externally applying a high gradient electromagnetic filter, an electromagnet using a DC power supply is used. This structure is described in Chemical Engineering, Vol. 45, No. 4, (1981), pp. 235-239.

[0003] As for a method of collecting and dewatering magnetic powder from a washing sludge of a magnetic separation part, a dewatering step by a centrifugal separation method is disclosed in Japanese Patent Application Laid-Open No. 60-244390. In this known example, an operation method of performing a dehydration treatment after removing magnetic powder from a magnetic aggregate is described.

Another method for recovering magnetic powder from magnetic aggregates is disclosed in Japanese Patent Application Laid-Open No. 60-61979, but in this known example, the magnetic aggregates are burned and the alga in the aggregates is burned. And the like to decompose and decompose organic substances.

[0005]

The problem to be solved by the present invention is disclosed in
Japanese Patent No. 244390 discloses that as a method of removing magnetic powder from a magnetic aggregate, the magnetic powder can be separated and collected from the magnetic aggregate only by a magnetic force only by passing the cleaning sludge through a high magnetic field. However, in practice, the operation method was reproduced, but no result was obtained in which only the magnetic powder was separated from the magnetic aggregate, and most of the magnetic powder flowed out of the magnetic field together with the aggregate. This is partly due to the fact that a polymer agent was added to increase the strength of the magnetic aggregate during the aggregating process, but the magnetic powder in the magnetic agglomerate was only magnetically driven by passing through a high magnetic field. When the suction is performed, the removal object, the coagulant, and the polymer agent around the magnetic powder are also sucked, and the magnetic powder cannot be selectively separated and separated.

Further, in the method disclosed in Japanese Patent Application Laid-Open No. 60-61979, carbides and the like adhere to and bind to the magnetic powder, thereby lowering the purity of the recovered magnetic powder and making it impossible to effectively use organic substances by composting. There is a problem.

[0007] In recent years, there has been a demand for a reduction in the operating cost of the purification treatment amount of the water treatment apparatus and an improvement in the magnetic separation efficiency. One of the methods is to increase the strength of the magnetic aggregate and to increase the magnetic separation unit. Increased magnetic attraction force, that is, increased magnetic field strength, strengthened the capture power of magnetic aggregates, and speeded up purification.Recovered and reused magnetic powder from separation sludge mixed with washing water and magnetic aggregates, magnetic powder This is an improvement in the dewatering rate of the sludge after separation.

An object of the present invention is to provide a structure of a purifying apparatus in which the efficiency of recovering magnetic powder from separated sludge is improved and the efficiency of dewatering treatment is improved.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for separating magnetically aggregated magnetically separated agglomerates from a magnetic separation unit by backwashing the separated sludge, applying mechanical shearing force to the magnetic separation units, and forming a magnetic separation unit. Most of the magnetic powder is recovered by passing through a device having the same, and then a polymer agent is added to the residual sludge again, and then the floc treatment is performed again, or the residual sludge is directly recovered from the magnetic powder through a centrifuge for dehydration. To dehydrate.

Also, drying, crushing,
By disposing a magnetic powder separator, the remaining magnetic powder is collected and reused without discarding the magnetic powder.

The separation sludge by backwashing is mechanically applied to the magnetic aggregate by a high-speed rotor or a spatula to separate the magnetic powder from the high-strength aggregate by magnetically separating only the magnetic powder. Can be recovered. In addition, by disposing the drying and crushing means on the downstream side of the centrifugal separator, the magnetic powder can be separated from the dried aggregates. Can be reused without giving up.

Furthermore, the dehydrated magnetic aggregate is dried,
By crushing and dismantling, it is possible to separate and collect magnetic powder with a higher purity than when separating after burning, and to separate and collect segregates other than magnetic powder, such as algae, without carbonizing them. Can be

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a basic processing flow of a magnetic separation apparatus will be described with reference to FIG.

The raw water in the reservoir 1 is passed through a filter 3 for removing large debris from the water pipe 2 and is pumped by a pump 4 into a raw water storage tank 5.
Is added to the raw water 6, and a magnetic powder of iron tetroxide and a coagulant such as polyaluminum chloride are added to the raw water 6 through a conduit 8, and a stirring machine 11 rotated by a motor 10 in a stirring tank 9. Pretreated water 1 containing magnetic floc
2 is manufactured. The pretreated water 12 is supplied through a valve 13 to a water pipe 14.
And flows into the magnetic separation container 15.

A DC power is supplied from the DC power supply 17 to the air-core coil 16. A magnetic field proportional to the direct current is generated in the cylindrical magnetic separation vessel 15, and the magnetic field is generated by the porous magnetic pole 1 for water flow.
8 and is surrounded by an iron yoke 19 to prevent leakage as a magnetic field line passage. The magnetic wire filling of the high gradient magnetic filter 20 is magnetized by the homogenized magnetic field. The magnetic field in the magnetic separation container 15 is disturbed by the magnetized magnetic fine wire filling, and the magnetic flux can be locally densified and dense, and many portions having a high magnetic field gradient are generated. When the pre-treated water 12 containing the magnetic flocs is supplied in an upward flow from below, the magnetic flocs in the raw water are captured by the magnetic fine wire surface of the filler with a large magnetic force, and the purified raw water is treated as the treated water by the valve 21, The water is temporarily stored in the treated water tank 23 through the water pipe 22, and returned to the reservoir 1 through the water pipe 24.

After a certain amount of magnetic flocs have been captured by the high gradient magnetic filter 20, a backwash of the filter is performed to restore the performance of the magnetic separation. In the backwash, first, the valve 13 is closed, and the supply of the pretreated water 12 is stopped. Next, the DC power supply is turned off, the magnetic field is removed, and after a predetermined amount of treated water flows backward from the upper part of the high gradient magnetic filter 20 through the valve 21, the valve 25 is opened. At this time, the valve 27 and the conduit 2 are connected from the air tank 26.
Air is supplied through 8 to carry out air bubbling to wash and remove magnetic flocks adhering to the surface of the magnetic fine wire, and to store washing water in a back washing water tank 29. This washing water is separately carried out from the backwashing water tank 29, and is discarded or incinerated in a landfill.

Thereafter, the valves 25 and 27 are closed, DC power is supplied from the DC power supply 17 to the air-core coil 16 again, and the valve 27 is opened to restart magnetic separation. In the present invention, only the magnetic powder is efficiently recovered from the washing water stored in the backwashing water tank, and the processing flow will be described with reference to FIG.

FIG. 1 shows a processing flow of a magnetic separator according to one embodiment of the present invention.

A source of water to be purified, for example, raw water from a reservoir 1 is temporarily stored in a raw water storage tank 5 by a pump 4 through a filter 3 for removing large debris from a water pipe 2, and the raw water is supplied from a chemical adjusting device 7 to ferric oxide or the like. Magnetic powder, a coagulant such as polyaluminum chloride, iron sulfide and the like, and a cohesion enhancer such as a polymer polymer for increasing the shear strength of the agglomerate. Produce pretreatment water.
The pretreatment water separates and captures magnetic aggregates in the magnetic separator 30,
The purified raw water is stored in the treated water tank 23a, and thereafter,
The water is returned to the reservoir 1 by the pump 23b.

The magnetic aggregate captured by the magnetic separator 30 is backwashed at a predetermined cycle, and the washing water containing the magnetic aggregate is stored in the backwash water tank 29. The magnetic separator 30 includes a plurality of, for example, two magnetic separating units 30a and 30b,
When one is backwashed, the other performs a cleaning operation and performs magnetic separation 3
At 0, the purifying operation is continuously performed.

The washing water in the backwashing water tank 29 is led to a magnetic powder recovery unit 31. That is, the magnetic aggregate is guided to a stirrer 31a that mechanically applies a shearing force to the magnetic aggregate by a high-speed rotating blade or a spatula that combines a flat plate and a spatula and relatively rotates on the flat plate. It breaks the binding force of the agent and breaks down the magnetic aggregates. Thereafter, the magnetic powder is separated and collected by a magnetic powder collecting magnetic separation device 31b formed of a rotating disk on which permanent magnets and the like are arranged, and the collected magnetic powder is returned to the medicine adjusting device 7 for reuse. Also, the magnetic powder recovery device gives relative speed to the flat plate with the magnet embedded and the spatula,
The stirrer 31a and the magnetic separation device 31b for collecting magnetic powder are integrally formed, and the magnetic aggregate is destroyed by a spatula made of an elastic material such as rubber while holding the magnetic aggregate on a flat plate by magnetic force. Alternatively, the magnetic powder alone may be retained and separated on a flat plate, and the magnetic powder may be scraped off at a single point on the rotating disk by a scraping plate and reused.

FIG. 2 shows a stirring device 31a and a magnetic separation device 31b for collecting magnetic powder. The washing water flows into the stirrer 31a through the hole 38 and is stirred by the high-speed rotating blades 38 to break the binding force of the polymer of the magnetic aggregate to break down the magnetic aggregate finely. The high-speed rotor 38 is driven by a motor 39, and the shaft 40 is supported by a watertight shaft seal 41. The motor 39 is connected to a power supply 42.

The stirred washing water flows into the magnetic separation device 31b for collecting magnetic powder. When the magnetic powder in the washing water passes by the side of the rotating disk 44 in which the permanent magnet 43 is fitted,
It is attracted to the surface of the permanent magnet 43. The rotating disk 44 is driven by a motor 45, and the shaft 46 is supported by a watertight shaft seal 47. The motor 45 is connected to a power supply 48.

The magnetic powder attracted to the surface of the permanent magnet 43 is scraped by scraping gutters 49 arranged on both sides of the rotating disk 44, and the scraped magnetic powder flows from the outlet 50 in the direction of gravity. Outflow from the outlet 50 is collected and reused. The cleaning water from which the magnetic powder has been removed flows out of the outlet 51.

Next, one embodiment of another apparatus for collecting magnetic powder is shown in FIG.

The agitating device 31a and the magnetic separation device 31b for collecting magnetic powder are integrated into the collecting device 31ab. The washing water flows into the agitating section through the hole 38, and the magnetic aggregates are permanently inserted into the rotating disk 52. It is attracted to the surface of the magnet 53.
The magnetic aggregate sucked by the rotating disk 52 rotates together with the disk, receives a strong shearing force with a spatula 54 made of hard rubber or the like and fixed to the recovery device 31ab, cuts off the bonding force of the polymer agent, and removes the magnetic aggregate. Disintegrate finely. Only the magnetic powder that has been disassembled is attracted to the permanent magnet 53 and is entrained along with the rotating disk 52, and is scraped off by the scraping gutters 49 arranged on both sides of the rotating disk 44.
From the outlet 50 in the direction of gravity to be collected and reused. The cleaning water from which the magnetic powder has been removed flows out of the outlet 51. Here, the spatula 54 is arranged in a plurality of stages in the circumferential direction of rotation of the rotating disk 52, and applies a shearing force to the magnetic agglomerate a plurality of times to further peel off the non-magnetic aggregating agent and the like adhered around the magnetic powder. May be increased.

The sludge of the washing water from which the magnetic powder has been separated and removed is a particle having a specific gravity larger than 1 in the chemical preparation device 31d,
For example, sand fine particles or slaked lime fine particles and a flocculant such as polyaluminum chloride and polyiron, a polymer polymer, and the like are re-charged, and the density of the flocculated material in which the amount of the magnetic powder is reduced by reaggregating in the mixing tank 31c is reduced. Then, the aggregate is efficiently separated and dehydrated by the centrifugal separator 31e. The water from which the sludge has been separated by the centrifugal separator 31e is returned to the reservoir 1 or to the suction side of the pump 4.

Further, by drying and crushing the dehydrated aggregate, and further recovering the remaining magnetic powder, magnetic powder having a higher purity can be separated and recovered as compared with the case of separating after burning.
Separates other than magnetic powder, for example, algae can be separated and collected without carbonizing, so that the isolates can be easily composted. Thereby, almost 100% of the magnetic powder can be recovered and reused without discarding the magnetic powder. The centrifugal separator 31e separates the aggregate from the washing water, further separates the water contained in the magnetic aggregate, greatly reduces the water content of the aggregate, and significantly reduces its volume. The aggregate separated and concentrated in the magnetic separation unit can be stored in a small-capacity sludge tank 32.

The agglomerates in the sludge tank 32 are further dried and dehydrated by, for example, a burner of a drying furnace 33 having a dust collecting function using oil as a fuel, and the heated gas passes through a deodorizer 34 filled with, for example, activated carbon and the like to the atmosphere. Released. After being pulverized into fine particles by the pulverizer 35, the remaining magnetic powder to which no carbide or the like adheres is collected by a magnetic powder separator 36 using a magnetic field such as a permanent magnet, and is reused as a magnetic separation agent. You. The separated material from which the magnetic powder has been removed is composted in the composting tank 37 and used as fertilizer.

Further, by using a superconducting coil as the air-core coil constituting the magnetic separator 30, the coil-generated magnetic field can be increased, and the coil can be reduced in size and weight. By increasing the generated magnetic field, the adsorptive power of the magnetic aggregate to be captured by the high gradient magnetic filter 20 increases, and the magnetic aggregate can be captured even when the pretreated water flows at a high speed.
By increasing the processing speed, high-speed purification becomes possible. Furthermore, the power consumption of the coil is greatly reduced, and the power supply equipment is reduced in size and weight. The same effect is obtained whether the superconducting coil is cooled by a liquid helium or liquid nitrogen refrigerant or by a mechanical or electronic refrigerator.

As described above, according to the present embodiment, the separation sludge by the backwash is mechanically applied to the magnetic aggregate by a high-speed rotating blade or a spatula to separate the aggregate from the magnetic powder, thereby obtaining the magnetic powder. Only the powder can be recovered with high efficiency by the magnetic separation means. Also, by placing the drying and crushing means on the downstream side of the centrifuge, the magnetic powder can be separated from the dried aggregates,
Thereafter, the magnetic powder is recovered by the magnetic separation means, whereby the magnetic powder can be recovered almost 100%, and can be reused without discarding the magnetic powder.

In this embodiment, since the sludge can be decomposed without adding a chemical such as sodium hydroxide to the sludge separated by the backwash, a neutralization step for returning the pH of the backwash water to the original state is not necessary.

As described above, even if all of the components according to the present invention are arranged on the ground, the first mobile unit up to the sludge tank,
Even if the remaining components are placed on the second mobile or on the ground,
Further, the same effect can be obtained even if the sludge tank is disposed underground and the rest is disposed above ground.

[0034]

According to the present invention, the separation sludge by backwashing is mechanically applied to the magnetic aggregate by a high-speed rotary blade or a spatula to separate the aggregate from the magnetic powder. Can be recovered with high efficiency by magnetic separation means.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a flow of a magnetic separation device according to an embodiment of the present invention.

FIG. 2 is a view for explaining the structure of a magnetic powder recovery unit of the magnetic separation device according to one embodiment of the present invention.

FIG. 3 is a view for explaining the structure of a magnetic powder recovery unit of a magnetic separation device according to another embodiment of the present invention.

FIG. 4 is a diagram illustrating a basic flow of an operation operation of the magnetic separation device.

[Explanation of symbols]

15: magnetic separation container, 20a, 20b: high gradient magnetic filter, 31: magnetic powder recovery device, 31a: stirring device, 31b
... Magnetic separator for collecting magnetic powder, 38 ... High-speed rotor, 44
... a rotating disk, 49 ... a gutter for scraping, 54 ... a spatula.

Claims (3)

[Claims] 1. A magnetic separation device comprising: a separation unit having a magnetic adsorbing means therein, wherein a magnetic substance and a coagulant are added to raw water to form a magnetic aggregate containing a substance to be removed and magnetically adsorbed and removed by the magnetic adsorption means An apparatus, comprising: a plurality of the magnetic attraction means; a first magnetic attraction means for forming a magnetic aggregate; and a shear force for mechanically applying a shear force to the magnetic aggregate to separate a magnetic substance from the magnetic aggregate. Second means for recovering the separated magnetic substance
And a dehydrating means for dehydrating and concentrating the remaining aggregates from which the magnetic substance has been removed by the second magnetic adsorbing means. 2. A magnetic separation apparatus according to claim 1, wherein said shearing force applying means is a stirrer having rotating blades. 3. A stirrer according to claim 1, wherein said shear force applying means and said second magnetic attraction means come into contact with a flat plate containing said second magnetic attraction means and have a relative speed. A magnetic separation device which is an integrated device having a rotor and a rotor for collecting magnetic powder.