JP2001150344A - Grinding method and grinding device for magnetic member, and disposal method and disposal device for waste liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding method and a grinding device for a magnetic member, and a disposal method and a disposal device for waste liquid, capable of being miniaturized and effective in separating fine sludge. SOLUTION: A grinding device 10 is provided with a cutting blade 38 having a cutting edge 44 containing a heat resistant resin 44b and abrasive grains 44a. A magnetic member 54 containing rare earth alloy is ground by using the cutting blade 38 while grinding liquid 58 taking water as a main component is supplied to a grinding part 60. Sludge 90 is magnetically separated form the spend grinding liquid 58 by a magnet separator 74 having the surface magnetic flux density of not less than 0.25T. When the grinding liquid 58 is supplied to a tank 92, the sludge 90 contained in the grinding liquid 58 is aggregated and precipitated. The grinding liquid 58 from which the sludge 90 is separated is used. When the sludge containing a rare earth alloy is separated from waste liquid, separating process is similarly performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for grinding a magnetic member, and a method and an apparatus for treating a waste liquid, and more particularly, to a method for purifying and reusing a grinding waste liquid containing sludge generated during grinding. The present invention relates to a grinding method and a grinding apparatus, a waste liquid treatment method and a treatment apparatus.

2. Description of the Related Art An example of a technique for purifying a grinding fluid is disclosed in Japanese Unexamined Patent Publication No. Hei.
No. 0-309647. Here, there is a technology in which a grinding fluid mixed with foreign matter is stored in a tank, the grinding fluid is stirred by a nozzle to separate sludge and abrasive grains from the grinding fluid, and the sludge is discharged out of the tank by a magnetic separator. Proposed. Another example of the related art is disclosed in Japanese Unexamined Patent Publication No.
No. 17 discloses. Here, a technique using a filter medium to purify the grinding fluid is proposed.

[0002]

However, with the former related technique, fine sludge cannot be sufficiently removed. In order to settle fine sludge and sufficiently remove the sludge, a large-capacity tank of about 3000 liters is required for one apparatus, and there is a problem that the apparatus becomes large. In addition, the sludge generated when grinding a magnetic member, particularly a rare earth alloy, is as fine as a few μm. However, the latter related technology using a filter medium causes clogging and efficiently removes such fine sludge. It was difficult to do. Furthermore, when the magnetic member is cut with a grinding blade containing a heat-resistant resin and superabrasive grains using a grinding fluid from which sludge has not been sufficiently removed, wear of the cutting edge is accelerated. Therefore, a main object of the present invention is to provide a magnetic member grinding method and a grinding device, and a waste liquid treatment method and a treatment device, which can be reduced in size and effective in separating fine sludge.

[0003]

According to a first aspect of the present invention, there is provided a method for grinding a magnetic member, comprising: a heat-resistant resin and superabrasive grains while supplying a grinding fluid to a grinding portion. The method includes a first step of grinding a magnetic member using a grinding means having a cutting edge, and a second step of magnetically separating sludge from a grinding fluid discharged from a grinding unit. Claim 2
The method of grinding a magnetic member according to the first aspect further includes a third step of precipitating sludge contained in the grinding fluid and separating the sludge from the grinding fluid in the method of grinding a magnetic member according to the first aspect. According to a third aspect of the present invention, in the method for grinding a magnetic member according to the first aspect, the magnetic member includes a rare earth alloy, and in the second step, the surface magnetic flux density is 0.25T or more. The sludge is separated using a separating means.

[0004] The method for grinding a magnetic member according to claim 4 is characterized in that:
In the method for grinding a magnetic member according to the first aspect, the grinding fluid contains water as a main component. According to a fifth aspect of the present invention, there is provided a method of grinding a magnetic member according to the first aspect, wherein the grinding fluid subjected to the sludge separation treatment is supplied to the grinding section and is circulated for use. According to a sixth aspect of the present invention, there is provided a method for separating a waste liquid from a waste liquid using a magnetic separation means having a surface magnetic flux density of 0.25 T or more.

According to a seventh aspect of the present invention, there is provided a method of treating a waste liquid according to the sixth aspect, wherein sludge contained in the waste liquid is further precipitated and separated from the waste liquid. The grinding apparatus for a magnetic member according to claim 8, wherein a grinding process for grinding the magnetic member using a grinding unit having a cutting edge including a heat-resistant resin and superabrasive grains while supplying a grinding fluid to the grinding unit. Means and magnetic separation means for separating sludge from the grinding fluid discharged from the grinding section. The apparatus for grinding a magnetic member according to a ninth aspect of the present invention is the apparatus for grinding a magnetic member according to the eighth aspect, further comprising a tank disposed downstream of the magnetic separation means and supplied with a grinding fluid. A magnetic member grinding apparatus according to a tenth aspect is the magnetic member grinding apparatus according to the eighth aspect, wherein the magnetic member includes a rare earth alloy, and a surface magnetic flux density of the magnetic separation unit is 0.25T or more. is there.

According to a magnetic member grinding apparatus according to an eleventh aspect, in the magnetic member grinding apparatus according to the eighth aspect, the grinding fluid contains water as a main component. According to a twelfth aspect of the present invention, there is provided the magnetic member grinding apparatus according to the ninth aspect, wherein the circulating means for supplying the circulating fluid subjected to the sludge separation treatment to the grinding unit for circulating use. Is further included. A waste liquid treatment apparatus according to a thirteenth aspect is provided with a magnetic separation means having a surface magnetic flux density of 0.25 T or more and separating sludge containing a rare earth alloy from the waste liquid. The waste liquid treatment device according to claim 14,
The waste liquid processing apparatus according to claim 13, further comprising a tank disposed downstream of the magnetic separation means and supplied with the waste liquid. The first step of grinding the magnetic member using a grinding means having a cutting edge including a heat-resistant resin and superabrasive grains while supplying a grinding fluid to the grinding section, and the grinding section, wherein the rare earth magnet according to claim 15 is provided. Obtained by using a method for grinding a magnetic member comprising a second step of magnetically separating sludge from a grinding fluid discharged from a grinding wheel.

In the method for grinding a magnetic member according to the first aspect, the sludge can be magnetically separated from the used grinding fluid by a magnetic separation means such as a magnet separator. However, the device can be downsized. Further, when the grinding means has a cutting edge containing a heat-resistant resin and super-abrasive grains, the cutting edge is liable to abnormally wear when fine sludge is contained in the grinding fluid, but the present invention also removes fine sludge from the grinding fluid. Since the separation can be performed, the occurrence of such an adverse effect can be suppressed, which is particularly effective. Further, the present invention is effective when obtaining a rare earth magnet as described in claim 15. The same applies to the magnetic member grinding apparatus according to the eighth aspect. Also,
When the grinding fluid is subjected to a magnetic separation treatment, sludge not separated from the grinding fluid is also magnetized. Therefore, in the method for grinding a magnetic member according to the second aspect, for example, by supplying the grinding fluid to the tank, the magnetized sludge contained in the grinding fluid can be agglomerated and quickly precipitated in the tank. At this time, even fine sludge which is difficult to settle is aggregated and settled, and can be quickly separated from the grinding fluid. Therefore, it is not necessary to use a large tank. The same applies to the magnetic member grinding apparatus according to the ninth aspect.

Rare earth alloys are liable to be oxidized, and if sludge is formed, it is considered that oxidation is more likely to proceed and non-magnetic portions are increased, so that the sludge containing the rare earth alloy is hard to be magnetically attracted. However, claim 3
In the method for grinding a magnetic member described in 1 above, the surface magnetic flux density is set to 0.
By using magnetic separation means of 25T or more,
The ability to separate sludge is increased, and as a result, the wear of the cutting means can be reduced. The same applies to the magnetic member grinding apparatus according to the tenth aspect. If the main component of the grinding fluid is water as in the method of grinding a magnetic member according to claim 4, the viscosity is lower than that of oil and the resistance at the time of suction is low, so that the sludge is sucked with a lower magnetic flux density. it can. The same applies to the magnetic member grinding apparatus according to the eleventh aspect. Claim 5
In the method for grinding a magnetic member described in (1), the grinding fluid subjected to the sludge separation treatment is supplied to the grinding unit and circulated for use, whereby the grinding fluid can be effectively used. The same applies to the magnetic member grinding apparatus according to the twelfth aspect.

In the waste liquid treatment method according to the sixth aspect, the use of the magnetic separation means having a surface magnetic flux density of 0.25 T or more facilitates separation of sludge containing a rare earth alloy, which is difficult to attract, from the waste liquid. The same applies to the waste liquid treatment apparatus according to the thirteenth aspect. Further, when the waste liquid is subjected to a magnetic separation treatment, the sludge not adsorbed by the magnetic separation means is also magnetized. Therefore, in the waste liquid treatment method according to claim 7, for example, the waste liquid after the magnetic separation is stored in a tank. , The magnetized sludge contained in the waste liquid is agglomerated and precipitated quickly in the tank. At this time, even fine sludge which does not easily precipitate is flocculated and precipitated, and can be quickly separated from the waste liquid. Therefore, it is not necessary to use a large tank. The same applies to the waste liquid treatment apparatus according to the fourteenth aspect.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. Referring to FIG. 1, a magnetic member grinding apparatus 10 according to an embodiment of the present invention includes a grinding processing unit 12 and a grinding processing unit 1 for grinding a magnetic member 54 (described later).
2 includes a purification unit 14 for separating sludge 90 (both described below) from the used grinding fluid 58 and purifying the grinding fluid 58, and a circulation unit 16 for supplying the purified grinding fluid 58 to the grinding processing unit 12 again. . The grinding processing section 12 includes a base 18, and a pan 22 having an outlet 20 for discharging a grinding fluid 58 and having an upper surface opening is disposed on the base 18.
The plate 24 is provided upright on the pan 22 so that the grinding fluid 58 does not scatter outside. On the pan 22, an overhang type X feed type cutting machine 25, which is a kind of so-called cantilever type, is provided. The cutting machine 25 includes a column 26 arranged on the pan 22. A support portion (not shown) is provided on one side surface of the column 26, and the rotation shaft 28 is rotatably supported by the support portion.

A cutting blade block 30 is mounted on the rotating shaft 28, one end of the rotating shaft 28 is supported by a support arm 32, and a pulley 34 is mounted on the other end of the rotating shaft 28. A belt 36 is mounted on the pulley 34, and the rotating shaft 28 and the cutting blade block 30 are rotated, for example, in the direction of arrow A by rotating the belt 36 by a rotating shaft motor (not shown). Referring to FIG. 2A, the cutting blade block 30 includes a plurality of cutting blades 38,
An annular spacer 40 is interposed between the cutting blades 38.
The cutting blade 38 includes a base plate 42 having a hollow disk shape, and a cutting edge 44 is attached to an outer peripheral edge of the base plate 42. As the base plate 42,
For example, a cemented carbide such as tungsten carbide, high-speed steel, or the like is used. The base plate 42 is a diamond sintered body obtained by sintering diamond or cBN (cubic boron nitride) or the like and a cemented carbide as disclosed in JP-A-8-109431 and JP-A-8-109432. Alloy base plates can also be used.

Further, as shown in FIG.
Is formed by mixing abrasive grains 44a and heat-resistant resin 44b. That is, the abrasive grains 44a are adhered to the base plate 42 by the heat-resistant resin 44b. For example, super-abrasive grains are used as abrasive grains 44a. As the superabrasive grains, natural or synthetic industrial diamond powder, cBN powder, a mixture of natural or synthetic industrial diamond powder-cBN powder, or the like is used. The grain size of the abrasive grains 44a is 160 μm to 250
It is set to about μm. As the heat resistant resin 44b, a thermosetting resin such as a phenol resin or a polyimide resin is used. Further, the heat-resistant resin 44b may contain metal powder of about several microns.

Returning to FIG. 1, two rails 46 are laid on the pan 22, and an X slider 48 is slidably mounted on the rails 46. A chuck table 50 is mounted on the X slider 48, and a sticking plate 52 is mounted thereon. A magnetic member 54 is fixed on the sticking plate 52 by an adhesive during grinding. As the magnetic member 54, for example, a rare earth alloy magnet member for a voice coil motor (VCM) is used. Such a rare earth alloy magnet member has a very high grinding resistance because it contains a hard main phase and a strongly sticky grain boundary phase. When such a material is ground with a cutting edge made of resin and abrasive grains, wear of the cutting edge is particularly problematic.

The voice coil motor mentioned here is used, for example, in a disk drive as shown in FIG. 9 of US Pat. No. 5,448,437. In FIG. 9, the voice coil motor is denoted by reference numeral 37. When the rare earth alloy magnet member is cut by the cutting blade 38 and then subjected to surface treatment, a rare earth magnet is obtained. Such rare earth magnets are disclosed, for example, in US Pat. No. 5,448,437.
It is used for the magnets indicated by reference numerals 3, 4, 5, 6 in FIGS. No. 4,770,723 and U.S. Pat. No. 4,795,723 disclose a method for producing an Nd--Fe--B rare earth magnet.
No. 2,368. Rare earth magnet is RT-
(M) -B based magnet, R is a rare earth element containing Y, T
Is Fe or Fe and Co, M is an additive, and B is boron.

Then, the X slider 48 is moved in the direction of arrow B (X
By sliding the magnetic member 54 at a constant speed toward the cutting blade block 30 rotating in the direction of arrow A, the magnetic member 54 can be cut to a predetermined size. The sludge 9 is cut by cutting the magnetic member 54.
0 occurs. At the time of cutting the magnetic member 54, as shown in FIG. 3, a grinding liquid 58 is supplied to the grinding unit 60 from a grinding liquid discharge device 56 arranged near the cutting blade 38.

The grinding fluid 58 used contains water as a main component.
For example, oil has a high viscosity, so that the sludge 90 is hard to move in the grinding fluid 58, whereas water has a low viscosity, so that the sludge 90 can be easily moved. Therefore, if the main component of the grinding fluid 58 is water, the sludge 90 can be sucked at a lower magnetic flux density. The grinding fluid discharge device 56 includes a retaining portion 64 connected to the grinding fluid supply path 62, and the retaining portion 64
Is supplied with a grinding liquid 58 from a grinding liquid supply path 62. Grinding liquid 58 is supplied from discharge port 66 formed at the tip of stagnation section 64 to 2αPa to 10αPa (α = 9.80665).
It is discharged to the grinding unit 60 at a pressure of × 10 ⁴ ). The angle of the discharge port 66 can be adjusted according to the size of the cutting blade 38.

Returning to FIG. 1, the grinding fluid 58 used in the grinding processing section 12 is supplied from the discharge port 20 of the pan 22 to the storage tank 70 of the purification section 14 via the grinding fluid discharge path 68.
Sludge 90 contained in the grinding fluid 58 is stored in the storage tank 70.
A barrier member 72 is provided in order to promote the sedimentation, and a magnet separator 74 is arranged near the barrier member 72. The magnet separator 74 includes a magnet roll 76 for adsorbing sludge 90 and a magnet roll 7.
6 includes a squeeze roll 78 for separating the sludge 90 and the grinding fluid 58 from each other. Note that the barrier member 72 is formed so as to warp upward so that the grinding fluid 58 easily contacts the magnet roll 76.

As shown in FIG. 4A, the magnet roll 76 includes a hollow cylindrical body 80, in which a cylindrical body 82 having a main shaft 81 penetrated is disposed. On the outer peripheral surface of the cylindrical body 82, for example, four magnets 84 are arranged at substantially equal intervals in the axial direction and the circumferential direction, respectively, for a total of 16 magnets 84. As shown in FIG. 4B, two types of magnets, each magnetized in the thickness direction, are used as the magnet 84. The magnets 84 adjacent in the circumferential direction are arranged so that the different poles correspond, and the magnets 84 adjacent in the axial direction also correspond to the different poles. The magnet 84 is composed of, for example, a neodymium magnet as shown in U.S. Pat. No. 4,770,723. The sludge 90 is a magnet 8
4 and is adsorbed on the surface of the cylindrical body 80.
The surface magnetic flux density of the outer peripheral surface of the cylindrical body 80 is 0.25T.
If it is (Tesla) or more, even sludge containing a rare earth alloy which is difficult to be attracted by the magnet 84 is easily separated from the grinding fluid 58. The magnet roll 76 is rotated, for example, in the direction of arrow C (see FIG. 5) by a motor (not shown). The surface magnetic flux density of the cylindrical body 80 is, for example, Gauss meter and probe (both manufactured by Bell Inc., sales agency: Toyo Tsusho Co., Ltd.)
The measurement is performed by bringing the probe into contact with the object to be measured using

Referring to FIGS. 1 and 5, sludge 90
Is supplied to the magnet separator 74 so as to overflow from the upper end of the barrier member 72. The sludge 90 is attracted to the magnet roll 76, and then the grinding fluid 58 on the magnet roll 76 is removed by the squeeze roll 78. Further, the sludge 90 adsorbed on the magnet roll 76 is scraped off by the scraper 86 in contact with the outer surface of the magnet roll 76, and is discharged to the sludge receiver 88. Thus, the sludge 90 is magnetically separated from the used grinding fluid 58 by the magnetic separator 74. The magnet separator 74 is particularly effective for separating fine sludge.

Grinding fluid 5 that has passed magnet roll 76
Reference numeral 8 denotes a tank 92 (barrier plate 9) disposed downstream of the magnet separator 74 and the storage tank 70 via a discharge port (not shown) provided below the magnet roll 76.
4 (to the right of the tank 92). Since the sludge 90 of the rare earth alloy has a small but coercive force as a magnet, the sludge 90 that has not been attracted to the magnet roll 76 is also magnetized by the magnet roll 76, so that the sludge 90 aggregates and forms inside the tank 92. Precipitates quickly. Further, in the tank 92,
Barrier plates 94 and 96 for preventing movement of sludge 90
And 98 are disposed, and the longer flow path promotes sedimentation of the sludge 90. At this time, the grinding fluid 58
Flows in a path as shown by arrow D. Therefore, in the process of passing through the tank 92, the sludge 90
2 and the separation of the sludge 90 and the grinding fluid 58 is further promoted. Further, even fine sludge is aggregated and precipitated and can be separated from the grinding fluid 58 quickly. As a result, a large tank is not required for separating the sludge 90 from the grinding fluid 58, and the apparatus can be downsized. In this way, the tank 92 which has been subjected to the separation treatment of the sludge 90 and purified is provided.
The grinding fluid 58 inside the pump 100
Is supplied to the grinding fluid discharge device 56 through the grinding fluid supply path 62 and is circulated for use.

The operation of the grinding device 10 will be briefly described. First, the grinding member 58 is supplied to the grinding unit 60 by the cutting blade 38 while supplying the grinding fluid 58 to the grinding unit 60.
After cutting 4, grinding fluid 58 containing sludge 90 flows into storage tank 70 via grinding fluid discharge passage 68. The grinding fluid 58 is supplied to the surface of the magnet separator 74, and the sludge 90
And other foreign substances are adsorbed. The grinding fluid 58 that has passed through the magnet separator 74 flows into the tank 92. Foreign matter such as sludge 90 remaining in the grinding fluid 58 is precipitated in the tank 92. Only the supernatant liquid in the tank 92 thus obtained is pumped up by the pump 100 and recirculated.
In addition, foreign substances such as sludge 90 settled in the tank 92 are scraped off as appropriate by any means. By cutting the magnetic member 54 by circulating and using the grinding fluid 58 from which the sludge 90 has been removed, the life of the cutting edge 44 can be extended. Here, an experimental example of the grinding device 10 will be described. Table 1 shows the experimental conditions.

[0022]

[Table 1]

As shown in Table 1, in this experimental example, the cutting edge 4
4 is a phenol resin and diamond abrasive grains (volume ratio 20
%). The outer diameter of the cutting blade 38 is 125 mm and the cutting edge 4
4 is 1.0 mm, the thickness of the base plate 42 is 0.9 mm,
The inner diameter of the base plate 42 is 40 mm, and the amount of the cutting edge (the height of the cutting edge 44)
Is 3 mm to 4 mm. The rotation speed (peripheral speed) of the cutting blade 38 is 2070 m / min, and the cutting speed is 10 mm / min.
min. As the grinding fluid 58, for example, JP-0497N manufactured by Castrol diluted with water by 2% (% by weight) is used. The cutting member is a rare earth alloy magnet member, and Neomax 44H manufactured by Sumitomo Special Metals Co., Ltd. is used.

Through the experiment, the results shown in FIGS. 6 to 8 were obtained. Here, “surface magnetic flux density” refers to the magnetic flux density on the outer surface of the cylindrical body 80 of the magnet separator 74.
The “sludge removal rate” refers to a value indicating how much sludge 90 contained in the grinding fluid 58 has been removed by passing the used grinding fluid 58 immediately after the grinding process through the magnet separator 74. The “processing removal amount” specifically refers to the volume (per one cutting blade 38) of a portion of the magnetic member 54 that has been cut into sludge 90 per 300 passes of cutting. The “amount of cutting blade wear” specifically refers to the cutting edge 44 of the cutting blade 38 per 300 passes of cutting.
Refers to the volume of the part that has been worn away (per one cutting blade 38). The “precipitation amount” refers to the amount of sludge 90 contained in the grinding fluid 58 per measured amount (in this case, 500 cc of the grinding fluid 58). The “sludge content ratio” refers to the weight ratio of the sludge 90 contained in the grinding fluid 58 per 500 cc.

The following experiments were performed under the conditions shown in Table 1. First, in Experiment 1, the amount of machining removal and the amount of wear of the cutting blade in the following cases (1) to (4) were compared (FIGS. 6A and 6B). One magnet separator (surface magnetic flux density 0.3
T) + tank, one magnet separator (surface magnetic flux density 0.25
T) + 1 tank, 1 magnetic separator (surface magnetic flux density 0.2
T) + Tank, No Magnet Separator + Tank As shown in FIGS. 6A and 6B, as the surface magnetic flux density of the magnet separator 74 increases, the cutting blade wear amount tends to decrease. Further, as the amount of processing removal increases, that is, as the number of times of cutting increases, the difference in the amount of wear of the cutting blade in each of the cases (1) to (4) increases. Even when the magnet separator 74 is used, in particular, when the magnetic flux density is 0.2
If it is 5T or more, the sludge 90 is efficiently removed, and the life of the cutting blade 38 can be extended.

Next, in Experiment 2, changes in the effect due to the number of the magnet separators 74 were compared in the following cases (FIGS. 7A and 7B). In this experiment, the surface magnetic flux density of the magnet separator 74 was set to 0.3T. One magnet separator + tank, two magnet separators + tank As shown in FIGS. 7A and 7B, it can be seen that sludge 90 can be removed by increasing the number of magnet separators 74.

Further, in Experiment 3, in the following cases, the effect of separating the sludge 90 due to the difference in the surface magnetic flux density of the magnet separator 74 was compared (FIG. 8).
(A) and (b)). With one magnet separator and no tank, and one magnet separator + tank, the sludge removal rate in the grinding fluid discharging device 56 was measured. As shown in FIGS. 8A and 8B,
It can be seen that when the magnetic flux density becomes 0.25 T or more, the removal rate of the sludge 90 is dramatically increased. In addition, it can be seen that the sludge removal rate is higher in the case. This indicates that the sludge 90 can be further separated by removing the sludge 90 with the magnet separator 74 and then settling the sludge 90 in the tank 92.

As can be seen from the above experimental examples, according to the grinding apparatus 10, since a large amount of sludge 90 in the grinding fluid 58 can be removed, the grinding fluid 58 can be recycled. That is, in general, in a grinding apparatus using a cutting blade having a cutting edge composed of a thermosetting resin and superabrasive grains (diamond-based abrasive grains), when a grinding fluid containing sludge is supplied to the grinding section, Alternatively, sludge accumulates between the cutting edge and the magnetic member to be cut, thereby causing clogging of the surface of the cutting blade or deteriorating sludge discharge during grinding. Further, at that time, the cutting resistance also increases, and the resin portion of the cutting blade causes abnormal wear, and the superabrasive grains are shed, so that the cutting efficiency also deteriorates. In a rare-earth alloy magnet member in which the magnetic member to be cut is composed of a hard main phase and a sticky grain boundary phase, the cutting load is particularly large and the cutting efficiency is extremely poor. If the situation continues, there is a problem that sludge gets into the pump for circulating the grinding fluid and causes abnormal wear, thereby increasing the temperature of the grinding fluid.

However, in the grinding apparatus 10, since the sludge 90 can be sufficiently removed from the grinding fluid 58, even if the grinding fluid 58 is circulated, the above-mentioned adverse effects can be suppressed, and the life of the cutting blade 38 can be reduced. Can be extended. Further, since the amount of the sludge 90 mixed in the pump 100 for circulating the grinding fluid 58 is also reduced, the pump 100 is not clogged, and as a result, abnormal wear of the pump 100 can be suppressed. Further, since the grinding fluid 58 can be circulated and used, the grinding fluid 58 can be effectively used. The grinding device 10
According to this method, the sludge 90 can be removed by the magnet separator 74, and the sludge 90 can be further aggregated and easily settled. Therefore, unlike the related art, a large tank is not required, and the apparatus can be downsized. For example, in the past,
Although a large-capacity tank of about 3000 liters was required, the tank 92 used in the grinding device 10 may have a capacity of about 600 liters.

Furthermore, if the surface magnetic flux density of the magnet separator 74 is set to 0.25 T or more, the separating ability of the sludge 90 is increased, and therefore, the abrasion of the heat-resistant resin 44b by the sludge 90 during grinding is reduced. In particular, when the cutting edge 44 of the cutting blade 38 is made of a heat-curable resin and diamond-based abrasive grains, the effect is enhanced. Sludge containing rare earth alloys is liable to agglomerate and easily clogs and rusts easily. Therefore, in the filter-type purifying device, the filter has to be replaced frequently, which is inefficient. In that regard, the grinding device 10 does not use a filter,
The replacement is not required, and the operating cost can be greatly reduced.

In the above-described embodiment, a case has been described in which a permanent magnet is used for the magnet separator 74 as the magnetic separation means. However, the present invention is not limited to this, and an electromagnet or the like may be used. As the grinding means, not only the cutting blade 38 but also any grinding means can be used. As other grinding means, 0.1 mm to 0.3 mm
Hard steel wire (piano wire) of about 30 to 60μm particle size
Wire fixed with a phenolic resin or the like having a thickness of 30 μm to 60 μm. The present invention can be applied to a case where a wire saw is performed using this wire. The present invention can be applied not only to the case where the sludge 90 is separated from the grinding fluid 58 but also to the case where a sludge containing a rare earth alloy is separated from any waste liquid.

[0032]

According to the present invention, since sludge can be magnetically separated from the grinding fluid, it is not necessary to use a large tank unlike the conventional one, and the apparatus can be downsized. Further, when the grinding means has a cutting edge containing a heat-resistant resin and super-abrasive grains, the cutting edge is liable to abnormally wear when fine sludge is contained in the grinding fluid, but the present invention also removes fine sludge from the grinding fluid. Since the separation can be performed, the occurrence of such an adverse effect can be suppressed, which is particularly effective. Further, the present invention is effective in obtaining a rare earth magnet.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

2A is a cross-sectional view schematically showing a cutting blade block, and FIG. 2B is a partial cross-sectional view schematically showing a cutting edge.

FIG. 3 is an illustrative view showing a grinding fluid discharging device arranged near a cutting blade;

FIG. 4A is a perspective view showing a magnet roll, and FIG. 4B is a perspective view showing a magnet.

FIG. 5 is an illustrative view for explaining a function of a scraper;

FIG. 6 (a) is a table showing the results of Experiment 1;
(B) is the graph.

FIG. 7 (a) is a table showing the results of Experiment 2;
(B) is the graph.

FIG. 8A is a table showing a result of Experiment 3;
(B) is the graph.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Grinding apparatus 12 Grinding processing part 14 Purification part 16 Circulation part 30 Cutting blade block 38 Cutting blade 44 Cutting edge 44a Abrasive grain 44b Heat resistant resin 54 Magnetic member 56 Grinding liquid discharge device 58 Grinding liquid 60 Grinding part 62 Grinding liquid supply path 68 Grinding Liquid discharge path 70 Storage tank 74 Magnet separator 90 Sludge 92 Tank 100 Pump

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3C047 FF06 GG13 GG17 3C058 AA03 AA09 AA14 AA18 AC01 AC04 CA01 CB03 CB05 CB09 CB10

Claims (15)

[Claims] 1. A first step of grinding a magnetic member using a grinding means having a cutting edge including a heat-resistant resin and superabrasive grains while supplying a grinding fluid to a grinding section, and discharging the grinding member from the grinding section. Second to magnetically separate sludge from grinding fluid
A method for grinding a magnetic member, comprising: 2. The method for grinding a magnetic member according to claim 1, further comprising a third step of precipitating sludge contained in the grinding fluid and separating the sludge from the grinding fluid. 3. The method according to claim 2, wherein the magnetic member includes a rare earth alloy, and in the second step, the sludge is separated using a magnetic separation unit having a surface magnetic flux density of 0.25 T or more.
The method for grinding a magnetic member according to claim 1. 4. The method for grinding a magnetic member according to claim 1, wherein the grinding fluid contains water as a main component. 5. The method for grinding a magnetic member according to claim 1, wherein the grinding fluid subjected to the sludge separation treatment is supplied to the grinding section and circulated for use. 6. A waste liquid treatment method comprising separating sludge containing a rare earth alloy from waste liquid using a magnetic separation means having a surface magnetic flux density of 0.25 T or more. 7. The method for treating waste liquid according to claim 6, wherein sludge contained in the waste liquid is further precipitated and separated from the waste liquid. 8. A grinding processing means for grinding a magnetic member using a grinding means having a cutting edge containing a heat-resistant resin and superabrasive grains while supplying a grinding fluid to a grinding section, and discharging from the grinding section. An apparatus for grinding a magnetic member, comprising: a magnetic separation unit for separating sludge from a grinding fluid to be performed. 9. The apparatus for grinding a magnetic member according to claim 8, further comprising a tank disposed downstream of said magnetic separation means and to which said grinding fluid is supplied. 10. The magnetic member grinding apparatus according to claim 8, wherein the magnetic member contains a rare earth alloy, and a surface magnetic flux density of the magnetic separation means is 0.25 T or more. 11. The apparatus for grinding a magnetic member according to claim 8, wherein the grinding fluid contains water as a main component. 12. The magnetic member grinding apparatus according to claim 8, further comprising a circulating means for supplying the grinding fluid having undergone the sludge separation treatment to the grinding section for circulating use. 13. An apparatus for treating waste liquid, comprising a magnetic separation means having a surface magnetic flux density of 0.25 T or more and separating sludge containing a rare earth alloy from the waste liquid. 14. The waste liquid processing apparatus according to claim 13, further comprising a tank disposed downstream of said magnetic separation means and to which said waste liquid is supplied. 15. A first step of grinding a magnetic member using a grinding means having a cutting edge containing a heat-resistant resin and superabrasive grains while supplying a grinding fluid to a grinding section, and discharging from the grinding section. A rare earth magnet obtained by using a magnetic member grinding method including a second step of magnetically separating sludge from a grinding fluid.