JP2001300597A - Solidifying method of grinding sludge and recycling system thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solidifying method and a recycling system which enable solidification to a prescribed strong briquette, reuse of coolant and easy reuse of the solidified briquette as steelmaking material even for the grinding sludge of hardened steel material containing on oil coolant. SOLUTION: This solidifying method of grinding sludge relates to a hardened steel part containing an oil coolant and the hardened part is steel material for bearing. The grinding sludge generated in a grinding line 1 is filtered by a filtering means 4 and concentrated sludge is obtained. The concentrated sludge is pressed and solidified by a briquette producing device 5 and the briquette (B) is produced. The briquette (B) thus obtained is reused as steelmaking material. The coolant separated from the sludge during processes of filter and press is returned to the grinding line 1 through recovery passages 7, 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention solidifies grinding sludge generated in a grinding line for hardened parts, for example, iron-based components such as inner and outer rings of rolling bearings and rolling elements, and other steel materials for bearings. The present invention relates to a solidification method for realizing recycling of grinding sludge by processing and a recycling system system.

[0002]

2. Description of the Related Art Iron-based components such as inner and outer races and rolling elements of a rolling bearing are hardened after quenching.
The rolling surface and the like are ground. The powdery grinding waste generated by the grinding is discharged as sludge together with the coolant outside the machine, and after filtration, the coolant is reused for grinding. Grinding sludge remaining by filtration is landfilled as sludge. FIG. 9 is a block diagram showing the flow of the processing. Grinding debris generated by the grinding machine 101 is conveyed through a pipe together with a coolant, filtered by a filtering means 102 such as a filter or a sedimentation facility, and the purified coolant is filtered by a coolant tank 103 for supply to the grinding machine 101. And return via pump. Since the grinding sludge remaining after filtration contains a large amount of coolant, it cannot be reused, and a disposal company of industrial waste performs disposal processing such as landfill. The amount of grinding waste generated by grinding is small compared to cutting, etc., but in mass production lines such as bearings, the amount generated is large, and landfilling of grinding sludge is not only unfavorable from the environmental point of view, but also Obviously, a deadlock in the treatment plant will prevent future landfill treatment.

[0003] For this reason, it has been studied to solidify the grinding sludge by squeezing it, reuse the squeezed coolant, and reuse the solidified material (hereinafter referred to as "briquette") as a steelmaking material. . Grinding sludge using an aqueous coolant can be easily solidified, and solidifying machines have already been sold. However, oil-based coolant has a higher viscosity than aqueous coolant, and grinding sludge using oil-based coolant has various problems in solidification.
For example, when squeezing, the oil-based coolant is difficult to be discharged, and even if the pressure during squeezing is simply increased, solidification cannot be performed to a required strength. Therefore, solidification of grinding sludge containing oil-based coolant has not yet been put to practical use.

[0004] In a grinding line for polishing and removing surface flaws of a metal strip in the process of manufacturing a rolled steel strip, grinding sludge is filtered, solidified by pressing and collected as briquettes, and is used for steelmaking. It has been proposed to use it again. In the grinding sludge generated by grinding the rolled steel strip, grinding chips in the grinding sludge are relatively soft and easily solidified. In addition, this grinding sludge has a low proportion of coolant, which also facilitates solidification. However, in the case of hardened part grinding sludge, grinding debris is hard and hard to harden. Therefore, it is necessary to squeeze strongly, but in the grinding sludge of oil-based coolant as described above,
Since it is difficult to discharge the coolant during squeezing, it is more difficult to solidify the coolant. Also, in the case of grinding sludge for hardened parts,
For example, for grinding 1 to 2 g of steel, several liters of coolant /
Since min is used, the ratio of coolant in the grinding sludge is large, and solidification is difficult because most of the coolant is coolant.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hardened briquette which can be solidified into a predetermined hard briquette even if it is a hardened steel sludge containing oil-based coolant, and the solidified briquette can be easily reused. An object of the present invention is to provide a solidification method and a solidification device. Another object of the present invention is a method of treating grinding sludge which can be solidified and reused even in the case of grinding sludge generated in a grinding line for quenched parts, and in which coolant generated in the process can be reused. , A recycling system including a processing device.

[0006]

A method for solidifying grinding sludge according to the present invention is a method for solidifying grinding sludge containing an oil-based coolant, wherein the grinding sludge is hardened grinding steel sludge. In this method, the grinding sludge is filtered to form concentrated sludge, and the concentrated sludge is solidified by pressing. According to this method, the grinding sludge is filtered to be concentrated sludge, and the concentrated sludge is solidified by pressing, so that the burden at the time of pressing is small, even if the grinding sludge contains oil-based coolant of a quenched steel material, Can be solidified. That is, the grinding waste is hard, fine, and needs to be hardened. Even grinding sludge in which it is difficult to squeeze out the coolant because of an oil-based coolant can be solidified. In addition, since the grinding sludge of the bearing steel is used, the solidified material (briquette) is a solidified product of grinding debris of the bearing steel, which is a high-quality steel, resulting in a high-quality steel product. Therefore, the solidified material can be reused as a steelmaking material.

In the method of the present invention, the grinding sludge before filtration may be a fluid having a coolant amount of 90 wt% or more. In the grinding of quenched products of bearing steel, such a large amount of grinding sludge of coolant is generated, but even such grinding sludge can be solidified by pressing, by making it into concentrated sludge by filtration. . The solidified material to be solidified preferably has a coolant amount in the range of 5 to 10 wt%. When the solidified material is reused as a steelmaking material, it is preferable that the amount of coolant as an impurity is small. If the amount of the coolant exceeds 10% by weight, it is difficult to reuse the steel as a steel product, and it is difficult to obtain a solidified material having such strength that it does not collapse during handling.

In the method of the present invention, in the filtration step, the grinding sludge may be guided to a filter belt, and the grinding sludge may be filtered under pressure by compressed air. By performing pressure filtration using a filter belt in this way, the dewatering effect by air blow or the like is good, and a high dewatering rate of sludge can be obtained. In addition, the filtration by the sludge accumulated on the filter belt works effectively, so that the filter belt has a long life and the filtration accuracy is good. Further, the concentrated sludge that has been filtered and adhered to the filter belt can be easily scraped off by moving the filter belt. The thickened sludge thus produced is entangled with curled short linear grinding debris and forms an important prerequisite for solidification.

When a plurality of types of coolant are used in the grinding line, it is preferable that the above-mentioned filtration and solidification by pressing are distributed to a plurality of series according to the type of the coolant. By performing the processing for each type of coolant in this way, the coolant generated in the process of filtration or squeezing is not mixed with another type of coolant, and the coolant can be easily reused. Also, conditions such as pressurization and pressing time during pressing can be set to appropriate conditions according to the type of coolant, and solidification can be easily performed.

[0010] The bearing steel material may be a component of a rolling bearing. The bearing components are, for example, an inner ring, an outer ring, and rolling elements. In the process of grinding rolling bearing components, oil-based coolant is often used,
In addition, grinding sludge is hard and fine, and grinding sludge which is difficult to solidify is generated. However, the grinding waste is grinding waste of high-quality bearing steel material, and since bearings are generally mass-produced, they become grinding sludge with a constant component. Therefore, when it is solidified, a high-quality solidified material is obtained as a steelmaking material. In addition, the conditions for pressing for solidification are easily set, and solidification can be stably performed by setting appropriate conditions.

[0011] The solidification device for grinding sludge of the present invention comprises:
An apparatus for solidifying grinding sludge containing an oil-based coolant, comprising: a filtering means for filtering the grinding sludge to obtain concentrated sludge; and a solidifying means for solidifying by compressing the concentrated sludge. The grinding sludge is a hardened bearing steel material sludge.
The solidification according to the method of the present invention can be performed by the apparatus having this configuration.

[0012] In the grinding sludge recycling system of the present invention, the grinding sludge generated in the grinding line for quenched parts is filtered to obtain a concentrated sludge, and the concentrated sludge is solidified by pressing. In this method, the coolant separated from the sludge is returned to the grinding line, and the solidified material is reused as a steel material. The quenched parts may be other than steel materials for bearings. According to this method, the grinding sludge can be solidified as in the solidification method described above. Since the solidified material is reused as a steel material and the coolant generated in the process is reused, resources can be used effectively and environmental pollution can be prevented.

In the recycling system of the present invention,
When using a plurality of types of coolant in the grinding line, means for performing the filtration, means for solidifying by pressing,
It is preferable that the path for conveying the grinding sludge from the grinding line to the filtering means and the recovery path for returning the coolant from the filtering means and the solidifying means to the grinding line be distributed to a plurality of series according to the type of the used coolant. . By distributing and processing according to the type of coolant in this way, solidification can be easily performed and coolant can be easily reused, as described in the above-described solidification method.

The grinding sludge recycling system according to the present invention is a recycling system for grinding sludge generated in a grinding line for quenched parts, wherein the grinding sludge is transported by the grinding means, and the transported grinding sludge is filtered to concentrate sludge. And a solidifying means for solidifying the concentrated sludge by squeezing the concentrated sludge to obtain a solidified material, and a recovery path for returning the coolant separated from the sludge to the grinding line during the filtration and squeezing. It may be.

[0015]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the concept of a processing method and a processing apparatus for grinding sludge, and FIG. 3 is a schematic explanatory view thereof. In the grinding line 1, grinding is performed by a grinding machine 2 using coolant supplied from a coolant tank 3. Grinding sludge made up of grinding chips and coolant generated in the grinding machine 2 is filtered by a filtering means 4, and the concentrated sludge generated by the filtration is solidified by being squeezed by a briquette manufacturing device 5 which is a solidifying means to form a briquette ( (Solidified product) B. The filtration device 4 and the briquette manufacturing device 5 constitute a solidifying device 6. The coolant generated by the filtration by the filtration means 4 and the coolant generated by the squeezing in the solidifying device 5 are returned to the coolant tank 3 of the grinding line 1 by the recovery paths 7 and 8, respectively. The coolant is returned from the recovery paths 7 and 8 to the coolant tank 3 via the filter and the pump. The coolant is supplied from the coolant tank 3 to the grinding machine 2 via a filter and a pump. Briquetting equipment 5
The briquettes B solidified in the above are transported to a steel maker 9 and used as steel products by the steel maker 9. The briquettes B are transported in a plurality of transport containers 10 called flexible container bags or the like as shown in FIG. In steelmaking maker 9, briquette B
Is used for steel products. The manufactured steel material is used as a material of an object to be ground.

The object to be ground in the grinding line 1 is a hardened part, such as bearing steel such as bearing steel. For example, the quenched component is an iron-based component of a rolling bearing, and specifically, a race such as an inner ring or an outer ring, or a rolling element such as a ball. Oil-based or water-based coolant is used as the coolant for grinding. Examples of the bearing steel material include a case hardened material of high carbon chrome steel (such as SUJ2), an induction hardened material of medium carbon steel (such as S53C), and a case hardened steel (SCR4).
15 etc.). The grinding sludge generated in the grinding machine 2 is a fluid having a coolant amount of 90 wt% or more, and the rest is powdery grinding dust and a small amount of grinding grains.
Grinding debris generally has a short, curled linear shape. In the state of the concentrated sludge filtered by the filtering means 4, this grinding sludge contains almost half of the coolant. The components of the concentrated sludge are, for example, approximately 50% by weight of grinding chips made of bearing steel and the like, and approximately 50% by weight of coolant.
And a small amount of abrasive grains. The component of briquette B is a steel material consisting mostly of grinding waste, and the amount of coolant is 5 to 5.
10 wt%, and contains a trace amount of abrasive grains remaining after most of the abrasive particles are discharged together with the coolant during the solidification treatment.
Even if the briquette B contains a very small amount of abrasive grains, if the grinding waste is a high-quality steel material such as a bearing steel, the use as a steelmaking material is not hindered. The briquette B has a predetermined strength, for example, a strength that does not result in three or more fragments even when dropped from a height of 1 m. Note that the briquette B does not contain any binder (such as cutting chips) for hardening grinding dust.

When a plurality of types of coolant are used in the grinding line 1, as shown in FIG. 2, the coolant is distributed to a plurality of processing sequences L1 and L2 depending on the type of the coolant used.
That is, a plurality of processing lines L1, each including a filtration means 4, a solidification means (briquette manufacturing apparatus 5), a transportation path 13 for transporting grinding sludge from the grinding line 1 to the filtration means 4, and coolant recovery paths 7 and 8, respectively. L2 is provided. Although FIG. 2 shows the two series L1 and L2, the number of processing series according to the type of coolant to be used is provided. The grinding line 1 referred to here is not limited to one line, but means a set of individual grinding lines, and may include all grinding machines in one factory, and may be an individual grinding line for each predetermined section in the factory. It may be a set of lines. By providing the plurality of lines L1 and L2 in this manner, grinding sludge containing different types of coolant is prevented from being collected for filtration or solidification. The processing series may be further divided into more series according to the steel type of the workpiece to be ground, in addition to the distribution according to the coolant type.

As shown in FIG. 3, the filtering means 4 includes a settling facility 15 and a filter facility 16. Grinding line 1
The grinding sludge generated in the above is first led to the sedimentation facility 15,
The precipitated grinding sludge is guided to the filter equipment 16 by the pump 17 and filtered again. In the precipitation equipment 15,
For example, a tank in which grinding sludge flows in a tangential direction of a circumference into a cylindrical tank having a conical bottom is used. By causing the grinding sludge to flow in the tangential direction in this manner, the grinding sludge is agitated in the tank in a vortex shape, so that grinding chips are uniformly distributed in the coolant. Filter equipment 16
A pressurized belt filter that uses a filter belt 18 and pressurizes and filters the grinding sludge with compressed air is used. In the recovery path 8 for recovering the coolant from the briquette manufacturing apparatus 5 to the coolant tank 3, a settling facility 15A is interposed to collect the filtered coolant. Instead of the settling equipment 15A, a filtering means for filtering by another method may be provided.

FIG. 4 shows an example of the filter equipment 16 comprising a pressurized belt filter. This filter equipment 16
Is a structure in which the interior of the container 19 is partitioned into an upper pressurizing chamber 19a and a lower chamber 19b by a horizontal path portion of an endless filter belt 18. The filter belt 18 is mounted on a pulley and is movable on a predetermined path. The pressurizing chamber 19a is provided with a grinding sludge inlet 21 via a distributor 20.
Further, a compressed air supply source 22 is connected.

The grinding sludge to be filtered is pump 1
Then, the pressure is sent through the inflow valve 24, and is uniformly pressed into the pressurizing chamber 19a from the distributor 20. The coolant in the press-fitted grinding sludge passes through the sludge deposited on the filter belt 18 and the filter belt 18.
The coolant cleaned by this passage is taken out of the lower chamber 19b and returned to the grinding line 1. When the predetermined filtration step is completed, the supply of the grinding sludge is stopped, and the air blow valve 25 is opened to introduce the compressed air into the pressurizing chamber 19a. The compressed air pushes the coolant remaining in the pressurizing chamber 19a through the deposition sludge into the lower chamber 19b, and then blows off the coolant adhering to the deposition sludge. When the air blowing is completed, the pressurizing chamber 19a is opened to the atmosphere and then the pressurizing chamber 19a is opened. In this state, the filter belt 18 is moved, and sludge on the belt 18 is removed.
It is scraped off by a scraper 26 outside the container 19 and discharged. The sludge thus scraped is concentrated sludge containing approximately half of the coolant as described above, and is conveyed to the briquette manufacturing apparatus 5 in the next step. According to the pressure filtration using the filter belt 18, the dewatering effect by air blow is good, and a high dewatering rate of sludge can be obtained.
In addition, the filtration by the sludge accumulated on the filter belt 18 works effectively, and the filter belt 18 has a long life and the filtration accuracy is good.

As shown in FIGS. 5 and 6, the briquette manufacturing apparatus 5 includes a primary press section 31 for storing a predetermined amount of concentrated sludge and pre-pressing the same, and pressing the pre-pressed sludge at a predetermined pressure. And a secondary press section 32 that solidifies by pressing. The primary press section 31 is a vertical cylinder type 1
The sludge in the next squeezing chamber 33 is transferred to the piston-like pressing member 4.
1 is a vertical press for pressing downward, and has a shutter 35 at its lower end for discharging pre-pressed sludge. The pressing member 41 includes a pressing drive source 42 such as a hydraulic cylinder.
Is driven up and down. Sludge inlet 38 is in primary press room 3
3 is provided on the side surface. The secondary press section 32 is a horizontal press section that presses the pre-pressed sludge B ′ in the horizontal cylinder-shaped secondary press chamber 34 in a substantially horizontal direction between the piston-shaped pressing members 43 and 44 on both sides. You. One end of the secondary pressing chamber 34 in the pressurizing direction is located below the shutter 35 and is a receiving portion 34a that can receive the pre-pressed sludge B 'from the shutter 35. Secondary pressing room 3
The other end of 4 is a briquette discharge port 34b, and a discharge path 47 for briquette B is formed by a chute or the like following the discharge port 34b. The pressing members 43 and 44 are driven forward and backward by pressure driving sources 45 and 46 such as hydraulic cylinders.

The sludge feeding section 36 for feeding the concentrated sludge into the primary press section 31 is a vertical sludge feeding section for dropping sludge from the hopper 37 to a sludge inlet 38 below the hopper 37. In the hopper 37, a stirring blade 39 for stirring the sludge inside and for pushing the sludge to the hopper outlet on the bottom surface is provided. In FIG. 5, the sludge charging section 36 is provided as shown by a two-dot chain line in FIG. 5, and is drawn out to another portion in FIG. The pressurizing drive sources 45 and 46 of the secondary press unit 32 are controlled by a pressurizing control unit 48 to a predetermined pressure and a predetermined compression speed. The primary pressing section 31 is provided with a heating means 40 (FIG. 6) for heating and maintaining the internal temperature within a predetermined temperature range.

The operation of the briquette manufacturing apparatus 5 will be described. With the shutter 35 closed, the hopper 37
Next, a certain amount of concentrated sludge is put into the press section 31, and the apparatus stands by for heating the sludge. When the temperature of the sludge in the primary press section 31 rises to a predetermined temperature range by heating by the heating means 40, the pressurizing member 41 is lowered and prepressed. The pre-pressed sludge B ′ is opened by opening the shutter 35 and receiving the one end of the secondary press part 32 a
To be dropped. Although this drop is performed by its own weight, it may be forcibly performed by lowering the pressing member 41 of the primary press unit 31. The pre-pressed sludge B ′ that has entered the secondary pressing section 32 is pressed in the secondary pressing chamber 34 by pressurization by the pressing members 43 and 44 on both sides, and solidified to form briquettes B. This squeezing is performed at a predetermined pressure and a predetermined compression speed. The briquette B manufactured in this manner is discharged from the briquette discharge port 34 b by retreating the discharge-side pressing member 44 and further moving the receiving-side pressing member 45, and is discharged through the discharge path 47. .

The manufactured briquette B has a cylindrical shape with an outer diameter equal to the inner diameter of the compression chamber 34 of the secondary press section 32,
Size. For example, as shown in FIG. 7, the briquette B has a cylindrical shape having a diameter D of about 80 mm and a height H of about 60 to 70 mm, and each piece has a weight of about 600 to 700 g. The shape of the briquette B is not particularly limited. For example, as shown in FIG. 8, a cylindrical shape having a through hole at the center (that is, a thick cylindrical shape), a prismatic shape, or a shape having a spherical end surface is used. And so on.

According to the method for solidifying or treating the grinding sludge, the grinding sludge is filtered to form a concentrated sludge containing approximately half the coolant, and the concentrated sludge is solidified by pressing. Even the grinding sludge containing the oil-based coolant of the steel material can be solidified. Further, since the grinding sludge of the bearing steel material is used, the solidified briquette is formed by solidifying grinding debris of the bearing steel material, which is a high-quality steel material, and becomes a high-quality steelmaking material. Therefore, the briquette can be reused as a steel material. Further, in the briquette manufacturing apparatus 5, the grinding sludge concentrated by filtration is pre-pressed in the primary press unit 31, and the pre-pressed sludge is further pressed in the secondary press unit 32 to be solidified. Even if it is a grinding sludge or a grinding sludge containing an oily coolant, it can be efficiently solidified. In other words, the pressing of the grinding sludge cannot be performed rapidly even when the pressure is increased due to the viscosity of the coolant and the minute gap between the grinding chips in the grinding sludge as described above. Difficult to reduce. However, by pre-pressing as described above and pressing it again in the secondary pressing section 32, appropriate pressing conditions can be set according to the pressing stage, and until the coolant amount is sufficiently reduced. It can be pressed and can be pressed efficiently. Therefore, even if it is a grinding sludge of a hardened part or a grinding sludge containing an oil-based coolant which is difficult to solidify, a solid briquette B which can be efficiently solidified and hardly collapses can be produced. As described above, since the briquette B is strong, the briquette B does not collapse during transportation or handling, and can be easily reused as a steel material.

[0026]

The method for solidifying grinding sludge according to the present invention is a method for solidifying grinding sludge containing an oil-based coolant, wherein the grinding sludge is hardened bearing steel which is quenched. The concentrated sludge is filtered and solidified by squeezing the concentrated sludge, so that even hardened steel sludge containing oil-based coolant can be solidified, and briquette, which is a solidified product, is a steelmaking material. It is of high quality and is easy to reuse. The solidification device of the grinding sludge of the present invention is a device for solidifying the grinding sludge containing the oil-based coolant, and the grinding sludge is a quenched bearing steel sludge, and the grinding sludge is filtered. Since it is provided with a filtration means for obtaining concentrated sludge and a solidifying means for solidifying the concentrated sludge by pressing to form briquettes, even if it is a grinding sludge of a quenched steel material containing an oil-based coolant, solidification is prevented. The solidified briquette is of high quality as a steel material and can be easily reused.

[Brief description of the drawings]

FIG. 1A is a block diagram showing a conceptual configuration of a method and an apparatus for solidifying grinding sludge according to an embodiment of the present invention, and FIG. 1B is an explanatory diagram of a processing process after the solidification. .

FIG. 2 is a block diagram showing a conceptual configuration of an example in which a plurality of solidification methods and solidification devices are used for the grinding sludge.

FIG. 3 is a schematic explanatory view of a method and a device for solidifying the grinding sludge.

FIG. 4 is a cross-sectional view of a filtering means in the solidifying device.

FIG. 5 is a sectional view of a briquette manufacturing apparatus in the solidifying apparatus.

FIG. 6 is a partially enlarged sectional view of the briquette manufacturing apparatus.

FIG. 7 is a perspective view showing an example of a briquette.

FIG. 8 is a perspective view showing a modified example of a briquette shape.

FIG. 9 is a block diagram showing a conventional grinding sludge processing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Grinding line 2 ... Grinding machine 3 ... Coolant tank 4 ... Filtration means 5 ... Briquette production equipment (solidification means) 6 ... Solidification equipment 7, 8 ... Recovery path 9 ... Steel making maker 11 ... Arc furnace 13 ... Transport path 15 ... settling equipment 16 ... filtration equipment 18 ... filter belt 31 ... primary press part 32 ... secondary press part L1, L2 ... processing route B ... briquette (solidified material)

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tetsuo Suzuki 1578 Higashikaizuka, Iwata-shi, Shizuoka Prefecture Inside NTN Iwata Mfg. Co., Ltd. Terms (reference) 3C047 GG17 4D026 BA03 BB05 BC12 BE06 BF21 4D059 AA10 AA30 BE09 BE15 BE31 BG00 CC07

Claims (11)

[Claims] 1. A method for solidifying grinding sludge containing oil-based coolant, wherein the grinding sludge is hardened bearing steel material, and the grinding sludge is filtered into concentrated sludge. Method for solidifying grinding sludge which is solidified by squeezing. 2. The method for solidifying grinding sludge according to claim 1, wherein the grinding sludge before the filtration is a fluid having a coolant amount of 90 wt% or more. 3. The method for solidifying grinding sludge according to claim 1, wherein the amount of coolant in the solidified product obtained by the solidification is 5 to 10 wt%. 4. The method for solidifying grinding sludge according to claim 1, wherein said grinding sludge is guided to a filter belt in said filtration step, and said grinding sludge is filtered under pressure by compressed air. 5. When a plurality of types of coolant are used in a grinding line, solidification by filtration and squeezing is performed by dividing into a plurality of series according to the type of coolant.
5. The method for solidifying grinding sludge according to claim 4. 6. The method for solidifying grinding sludge according to claim 1, wherein the bearing steel material is a component of a rolling bearing. 7. An apparatus for solidifying grinding sludge containing oil-based coolant, wherein the grinding sludge is a hardened bearing steel sludge, and a filtration means for filtering the grinding sludge to obtain concentrated sludge. And a solidifying means for solidifying the concentrated sludge by pressing. 8. Grinding sludge generated in a grinding line for a quenched part is filtered to obtain concentrated sludge, and the concentrated sludge is solidified by pressing, and the coolant separated from sludge in the process of the filtration and pressing is ground. A grinding sludge recycling system that returns to the line and reuses the solidified material obtained by the solidification as a steelmaking material. 9. The grinding sludge recycling system according to claim 8, wherein the hardened part is a steel material for bearing. 10. When a plurality of types of coolant are used in the grinding line, the means for performing filtration, the means for solidifying by pressing, a path for transporting grinding sludge from the grinding line to the filtering means, and a coolant are provided. The recovery route from the filtration means and solidification means to the grinding line is
The grinding sludge recycling system according to claim 9, wherein the grinding sludge is distributed to a plurality of series according to a type of a used coolant. 11. A recycling system for grinding sludge generated in a grinding line for quenched parts, comprising: means for transporting the grinding sludge; filtering means for filtering the transported grinding sludge to obtain concentrated sludge; A grinding sludge recycling system comprising: a solidifying means for solidifying a sludge by pressing to obtain a solidified product; and a recovery path for returning a coolant separated from the sludge in a process of the filtration and the pressing to a grinding line.