JP3950391B2 - Wire saw slurry management system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a wire saw slurry management apparatus that can reliably and efficiently recover a dispersion from a wire saw waste slurry.
[0002]
[Prior art]
Conventionally, when making a wafer from materials such as ceramics, IC chip substrates, silicon for solar cells, and synthetic quartz, an apparatus called a wire saw has been used. This wire saw is provided with a plurality of wires stretched endlessly between processing rollers in parallel, and slurry in which abrasive grains are dispersed in a dispersion is supplied to the wire. As the dispersion, an aqueous dispersion or an oil dispersion is generally used.
[0003]
When cutting an object to be cut such as a ceramic or IC chip substrate with a wire saw, slurry in which abrasive grains are dispersed in a dispersion is supplied to the wire, and at the same time, a processing roller is driven to drive the wire. In a state of being moved, the wire and the object to be cut are brought close to each other, and the object to be cut is cut by passing the object to be cut with respect to the wire to produce a large number of wafers.
[0004]
Since the cutting ability of the wire greatly depends on the mixing weight ratio of the abrasive grains in the slurry supplied to the wire and the dispersion liquid, in order to efficiently cut the object to be cut, the abrasive grains in the slurry It is necessary to maintain the mixing weight ratio with the dispersion at a value that maximizes the cutting ability of the wire.
[0005]
In addition, the slurry supplied to the wire saw is mixed with chips from the workpiece by cutting the workpiece, and for this reason, the waste slurry after cutting increases the amount of chips and decreases the proportion of abrasive grains. And the cutting efficiency of a to-be-cut object falls with time for the reason that the abrasive grains are crushed at the time of cutting and the amount of abrasive grains having a particle size usable for cutting decreases.
[0006]
For this reason, conventionally, every time the cutting process is completed a predetermined number of times, a certain amount of waste slurry is discharged, and a new slurry having the same amount as the discharged waste slurry is supplied.
[0007]
However, even if a part of the waste slurry is periodically replaced in this way, the amount of chips and crushed abrasive grains in the slurry gradually increases, so the abrasive grains and the dispersion liquid in the slurry The mixing weight ratio cannot always be maintained at an optimum value. For this reason, the cutting ability of the wire gradually decreased, and it was impossible to maintain a uniform and stable cutting efficiency.
[0008]
In addition, in the conventional wire saw, the waste slurry taken out when the slurry is replaced is discarded. This waste slurry to be discarded contains usable abrasive grains and dispersion liquid, and it is a wasteful consumption of resources to discard this and supply new abrasive grains and dispersion liquid, which is necessary for cutting processing. There has been a problem that the consumption of such abrasive grains and dispersion increases and the cost of the cutting process increases. In addition, since the waste slurry to be discarded is disposed as industrial waste, there is a problem that the load of industrial waste processing increases.
[0009]
In recent years, in order to solve the above-described problems, the waste slurry is supplied to a centrifuge to separate and remove solids having a relatively large particle size, and then supplied to a filter to obtain fine solids. A method is considered in which a clean dispersion is obtained by separating and removing the components, and abrasive grains are dispersed in the recovered dispersion and supplied to the wire saw again.
[0010]
[Problems to be solved by the invention]
However, as described above, the method of removing the solid content in the waste slurry by using a centrifuge and a filter and recovering the dispersion is theoretically possible, but in practice it can be separated. There wasn't.
[0011]
That is, a normal dispersion has viscosity, and separation is very difficult because a fine solid content of about several microns is mixed in the waste slurry at a high concentration. The centrifuge can only separate solids with a certain size of particle size, and as a result, fine solids of several microns are separated by a filter, but such fine particles have a high concentration. There is no filter that can efficiently separate the fine particles from the mixed liquid. That is, the filter part of the filter is immediately clogged. For this reason, it is technically difficult to continuously and efficiently separate the solid content and the dispersion from the waste slurry as described above.
[0012]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wire saw slurry management apparatus that can efficiently and reliably recover a dispersion from a wire saw waste slurry.
[0013]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention according to claim 1 is directed to a wire saw that performs cutting by introducing a slurry in which abrasive grains are dispersed in a dispersion, and a waste slurry that is generated from the wire saw. Evaporation from the vacuum dryer, with one side communicating with the vacuum dryer and the other side communicating with a vacuum suction device, vacuum drying while heating above the evaporation temperature to separate into solids and evaporation vapor A condenser for liquefying the vapor, a dispersion storage tank for storing the dispersion liquefied by the condenser, and a mist separator for removing solids from the evaporated vapor separated by the vacuum dryer The present invention relates to a slurry management device for a wire saw.
[0014]
[0015]
[0016]
According to a second aspect of the present invention, there is provided the wire saw slurry management apparatus according to the first aspect, wherein a component adjusting device is provided in the dispersion liquid storage tank.
[0017]
[0018]
A third aspect of the present invention relates to the wire saw slurry management apparatus according to the first aspect, wherein the condenser is provided in a plurality of stages.
[0019]
According to a fourth aspect of the present invention, the waste slurry generated at the time of cutting the wire saw is centrifuged to separate coarse solids and waste slurry, and the coarse solids are guided to the wire saw together with the recovered dispersion, 2. The wire saw slurry management apparatus according to claim 1, further comprising a centrifuge configured to guide the slurry to the vacuum dryer.
[0020]
A fifth aspect of the present invention relates to the wire saw slurry management apparatus according to the fourth aspect, wherein the centrifuge is provided in a plurality of stages.
[0021]
According to the above means, it operates as follows.
[0022]
In the first aspect of the invention, the wire saw waste slurry is heated to a temperature equal to or higher than the evaporation temperature of the dispersion and vacuum dried to separate the solids and the evaporation vapor, and the separated evaporation vapor is condensed to disperse the dispersion. Since the abrasive grains are dispersed in the recovered dispersion and supplied to the wire saw again, most of the dispersion in the waste slurry can be reliably recovered and reused. The slurry management cost can be reduced as much as possible, and the economy can be improved. Further, the amount of waste is reduced, which is advantageous in terms of environmental conservation, and the waste treatment cost can be reduced. Furthermore, since the mist separator which removes mist from the evaporation vapor isolate | separated with the vacuum dryer is provided, the solid content in evaporation vapor can be isolate | separated.
[0023]
[0024]
In the invention described in claim 2, since the component storage device is provided in the dispersion liquid storage tank, the components of the recovered dispersion liquid can be easily adjusted.
[0025]
In the invention of claim 3, the evaporation vapor can be liquefied more completely by providing a plurality of condensers.
[0026]
In the invention according to claim 4, since the coarse solid content in the waste slurry is removed by the centrifuge, the waste slurry is guided to the vacuum dryer and separated into the solid content and the evaporation vapor. The solid content concentration of the slurry can be lowered and led to a vacuum dryer, and can be reused by dispersing the separated coarse solid content in the dispersion as part of the abrasive grains.
[0027]
In the invention according to claim 5, the solid content concentration in the waste slurry led to the vacuum dryer can be further lowered by providing a plurality of centrifuges.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Preferred embodiments of the invention will be described below with reference to the drawings.
[0029]
FIG. 1 is an elevation view showing the overall configuration of one embodiment of the wire saw slurry management apparatus of the present invention, and FIG. 2 is a system diagram of the dispersion liquid recovery apparatus in FIG.
[0030]
As shown in FIG. 1, the slurry 3 from the regenerated slurry tank 2 is supplied to the wire saw 1 by a pump 4. In the regenerated slurry tank 2, the separated and collected coarse solid content 14, an aqueous or oil-based dispersion 5 and new abrasive grains 6 are dispersed and mixed by a stirrer 7.
[0031]
The waste slurry 8 generated by cutting the object to be cut with the wire saw 1 is stored in a waste slurry tank 9, and solid waste is prevented from being precipitated by the stirrer 10 in the waste slurry tank 9.
[0032]
The waste slurry 8 in the waste slurry tank 9 is taken out by the pump 11 and supplied to the dispersion liquid recovery device 12 as indicated by the broken line, whereby the dispersion liquid can be recovered.
[0033]
On the other hand, the example of FIG. 1 shows a case where the waste slurry 8 in the waste slurry tank 9 is supplied to the first centrifuge 13 as shown by the solid line by the pump 11. In the first centrifuge 13, the coarse solid content 14 in the waste slurry 8 is separated by centrifugal force, and the coarse solid content 14 is guided to the regenerated slurry tank 2 as a part of the abrasive grains 6 together with the dispersion 5. I am doing so. The waste slurry 8 from which the coarse solid content 14 has been separated by the centrifugal separator 13 is stored in a waste slurry tank 16 equipped with a stirrer 15.
[0034]
The waste slurry 8 in the waste slurry tank 16 is supplied to the second centrifuge 18 by the pump 17. In the second centrifuge 18, the solid content 19 in the waste slurry 8 is separated by a higher centrifugal force, and the waste slurry 8 from which the solid content 19 has been separated is stored in a waste slurry tank 21 provided with a stirrer 20. . Thus, the waste slurry 8 from which the solid content is separated to some extent by the first and second centrifuges 13 and 18 is supplied to the dispersion liquid recovery device 12 via the pump 22. A part of the waste slurry 8 from the pump 22 is supplied to the second centrifuge 18. Further, in the above, a bypass flow path 23 is provided downstream of the pump 17, and a part of the waste slurry 8 from the pump 17 is dispersed together with the waste slurry 8 from the pump 22 without being led to the second centrifuge 18. It may be guided to the liquid recovery device 12.
[0035]
In the dispersion liquid recovery device 12, the solid content 19 is separated to recover the dispersion liquid 5, and the recovered dispersion liquid 5 is supplied to a dispersion liquid storage tank 25 provided with a stirrer 24. In the dispersion liquid storage tank 25, the component inspection of the dispersion liquid 5 is performed, and a component adjusting device 26 is provided so as to replenish the insufficient component.
[0036]
The dispersion 5 in the dispersion storage tank 25 is supplied to the regenerated slurry tank 2 by a pump 27, and a part of the dispersion 5 is supplied to the first centrifuge 13. It has become so.
[0037]
Next, the dispersion liquid recovery apparatus 12 will be described with reference to FIG.
[0038]
The waste slurry 8 from the waste slurry tank 21 or the waste slurry tank 9 is supplied to a vacuum dryer 28 so as to be separated into the solid content 19 and the evaporation vapor 5a. The vacuum dryer 28 includes a central shaft 31 that is rotated by a rotary motor 30 inside a cylindrical body 29, and the central shaft 31 includes a stirring blade 32. The waste slurry 8 is supplied into the cylindrical body 29 from the waste slurry supply port 33 and is stirred by the stirring blade 32.
[0039]
A suction drum portion 34 for taking out the evaporated vapor 5a is formed at the upper part of the intermediate position in the axial direction of the cylindrical body 29. The suction drum portion 34 is sucked by a vacuum suction device 45 described later. Reference numeral 40 denotes a solid content cutting device for taking out the solid content 19 separated in the vacuum dryer 28 to the outside.
[0040]
Further, a jacket 35 is provided on the outer periphery of the cylindrical body 29, and a heating fluid 37 such as steam from the heating fluid supply device 36 is supplied to the jacket 35 and the central shaft 31 through a supply pipe 38. Yes. Reference numeral 39 denotes a return pipe for the heating fluid 37.
[0041]
The heating in the vacuum dryer 28 is maintained at a heating temperature of approximately 100 ° C. when the dispersion 5 is an aqueous dispersion, and is approximately 300 ° C. when the dispersion 5 is an oil-based dispersion. The heating temperature is maintained. Therefore, as the heating fluid supply device 36, an existing steam boiler, other various heating devices, and a heating medium can be used as long as the heating temperature can be maintained.
[0042]
A mist separator 41 for removing solid content from the evaporation vapor 5a is provided on the downstream side of the suction drum 34 of the vacuum dryer 28. The mist 42 separated by the mist separator 41 is returned to the vacuum dryer 28.
[0043]
A condenser is provided downstream of the mist separator 41 to take out the dispersion 5 by introducing the evaporation vapor 5a from the mist separator 41, cooling it and liquefying it. FIG. 2 shows a case where a first condenser 43 and a second condenser 44 are provided in series, and a vacuum suction device 45 is connected to the second condenser 44. The vacuum suction device 45 supplies the water in the ejector water tank 46 to the ejector 48 by the ejector pump 47 and vacuums the gas in the second condenser 44 through the exhaust pipe 49. Alternatively, a vacuum pump can be used as the vacuum suction device.
[0044]
The first condenser 43 and the second condenser 44 are cooled by supplying cold water 51 from a cold water supply device such as a cold water tower (not shown) to a cooling water pipe 50 provided therein, and evaporating vapor. The dispersion 5, which is condensed and liquefied by cooling 5 a, is extracted from the lower extraction portion 52 by the dispersion extraction pump 53 and collected in the dispersion storage tank 25.
[0045]
The operation of the above embodiment will be described below.
[0046]
In the dispersion liquid storage tank 25 of FIG. 1, the component adjustment of the dispersion liquid 5 is performed by the component adjustment device 26, and the component-adjusted dispersion liquid 5 is supplied to the regenerated slurry tank 2 by the pump 27. In the regenerated slurry tank 2, a predetermined amount of new abrasive grains 6 is supplied and mixed by a stirrer 7, and the slurry 3 adjusted in this way is supplied to the wire saw 1 by the pump 4 and is cut by the wire saw 1. Is called.
[0047]
The waste slurry 8 generated by cutting the object to be cut with the wire saw 1 is stored in the waste slurry tank 9 and then supplied to the first centrifuge 13 by the pump 11, and the first centrifuge 13 The coarse solid content 14 in the waste slurry 8 is separated by centrifugal force, and the coarse solid content 14 is guided to the regenerated slurry tank 2 together with the dispersion 5 and mixed and used as a part of abrasive grains.
[0048]
The waste slurry 8 from which the coarse solid content 14 has been separated by the first centrifuge 13 is stored in the waste slurry tank 16 and then supplied to the second centrifuge 18 by the pump 17. The solid content 19 in the waste slurry 8 is separated by a higher centrifugal force in the separator 18, and the waste slurry 8 from which the solid content 19 has been separated is stored in the waste slurry tank 21. The solid content separated by the first centrifuge 13 and the second centrifuge 18 is very small, and the waste slurry 8 in the waste slurry tank 21 still contains a large amount of fine solids. Existing.
[0049]
The waste slurry 8 from which the coarse solid content has been separated to some extent by the first and second centrifuges 13 and 18 is supplied to the vacuum dryer 28 in the dispersion liquid recovery apparatus 12 of FIG. The
[0050]
The inside of the vacuum dryer 28 is kept in a vacuum by a vacuum suction device 45, and a heating fluid 37 such as steam from a heating fluid supply device 36 is supplied to the jacket 35 and the central shaft 31 to be heated. Therefore, the dispersion liquid of the waste slurry 8 supplied to the vacuum dryer 28 and stirred by the stirring blade 32 is effectively evaporated to become the evaporation vapor 5a and guided to the mist separator 41. The solid content 19 remaining after evaporation of the dispersion is taken out by the solid content cutting device 40.
[0051]
The heating temperature in the vacuum dryer 28 is approximately 100 ° C. when the dispersion 5 is an aqueous dispersion, and approximately 300 ° C. when the dispersion 5 is an oil-based dispersion. Heat with. In the case of a normal aqueous dispersion, it is necessary to heat at about 180 ° C. to evaporate at normal pressure, and in the case where the dispersion 5 is an oil-based dispersion, it is heated at about 500 ° C. to evaporate at normal pressure. However, when heated in a vacuum-sucked state as described above, it can be efficiently separated by evaporating at a low temperature, and alteration of the dispersion 5 can be prevented by lowering the heating temperature.
[0052]
The evaporation vapor 5 a from the vacuum dryer 28 is separated from the mist 42 by the mist separator 41, so that the mist 42 contains a solid content, and the mist 42 containing the solid content is returned to the vacuum dryer 28. It is.
[0053]
The evaporation vapor 5 a from which the mist 42 has been separated by the mist separator 41 is liquefied by being cooled by the first condenser 43. Subsequently, by being cooled by the second condenser 44, the evaporated vapor 5a that has not been liquefied by the first condenser 43 is liquefied, whereby most of the evaporated vapor 5a is liquefied.
[0054]
The dispersion 5 liquefied by the first condenser 43 and the second condenser 44 is extracted by the dispersion extraction pump 53 and collected in the dispersion storage tank 25.
[0055]
Then, the dispersion 5 collected in the dispersion storage tank 25 is subjected to component inspection, and after the missing component is replenished by the component adjustment device 26, it is supplied again to the regenerated slurry tank 2 of FIG. .
[0056]
By providing the above-described dispersion liquid recovery device 12, most of the dispersion liquid in the waste slurry 8 can be reliably recovered and reused, and the slurry management cost of the wire saw 1 can be reduced as much as possible. Economic efficiency can be improved, and further, the amount of waste is reduced, which is advantageous in terms of environmental conservation, and waste disposal costs can be reduced.
[0057]
It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.
[0058]
【The invention's effect】
According to the first aspect of the present invention, the waste slurry of the wire saw is heated to a temperature equal to or higher than the evaporation temperature of the dispersion and vacuum dried to separate the solid content and the evaporated vapor, and by condensing the separated evaporated vapor. Since the dispersion liquid is recovered, and the abrasive grains are dispersed in the recovered dispersion liquid and supplied to the wire saw again, most of the dispersion liquid in the waste slurry can be reliably recovered and reused. The cost of wire saw slurry management can be reduced as much as possible, and the economic efficiency can be increased. Further, the amount of waste is reduced, which is advantageous in terms of environmental conservation, and the cost of waste treatment can be reduced. Since the mist separator that can remove mist from the evaporated vapor separated by the vacuum dryer is provided, the solid content in the evaporated vapor can be separated.
[0059]
[0060]
According to the second aspect of the present invention, since the component storage device is provided in the dispersion liquid storage tank, there is an effect that the components of the recovered dispersion can be easily adjusted.
[0061]
According to the invention described in claim 3, since the condenser is provided in a plurality of stages, there is an effect that the evaporation vapor can be liquefied more completely.
[0062]
According to the invention of claim 4, since the coarse solid content in the waste slurry is removed by the centrifuge, the waste slurry is guided to the vacuum dryer and separated into the solid content and the evaporation vapor. The solid content concentration of the waste slurry can be reduced and led to a vacuum dryer, and the separated coarse solid content can be reused by dispersing it in the dispersion as part of the abrasive grains.
[0063]
According to the invention described in claim 5, since the centrifuges are provided in a plurality of stages, there is an effect that the solid content concentration in the waste slurry led to the vacuum dryer can be further reduced.
[Brief description of the drawings]
FIG. 1 is an elevational view showing the overall configuration of an embodiment of a wire saw slurry management apparatus according to the present invention.
FIG. 2 is a system diagram of the dispersion liquid recovery apparatus in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wire saw 3 Slurry 5 Dispersion liquid 5a Evaporation vapor 6 Abrasive grain 8 Waste slurry 12 Dispersion liquid recovery apparatus 13 1st centrifuge (centrifuge)
14 Coarse grain solids 18 Second centrifuge (centrifuge)
DESCRIPTION OF SYMBOLS 19 Solid content 25 Dispersion liquid storage tank 26 Component adjustment apparatus 28 Vacuum dryer 36 Heating fluid supply apparatus 37 Heating fluid 41 Mist separator 43 1st condenser (condenser)
44 Second condenser (condenser)
45 Vacuum suction device

Claims (5)

  A wire saw that performs cutting by introducing a slurry in which abrasive grains are dispersed in a dispersion liquid, and a waste slurry generated from the wire saw is introduced and heated to a temperature equal to or higher than the evaporation temperature of the dispersion liquid. A vacuum dryer that separates into a vacuum dryer, one side that communicates with the vacuum dryer and the other side that communicates with a vacuum suction device, and liquefies the evaporated vapor from the vacuum dryer, and a dispersion liquefied by the condenser And a mist separator for removing solid content from the evaporation vapor separated by the vacuum dryer.   2. The wire saw slurry management apparatus according to claim 1, wherein a component adjusting device is provided in the dispersion liquid storage tank.   2. The wire saw slurry management apparatus according to claim 1, wherein the condenser is provided in a plurality of stages.   The waste slurry generated during the cutting of the wire saw is centrifuged to separate coarse solids and waste slurry, the coarse solids are guided to the wire saw together with the recovered dispersion, and the waste slurry is guided to the vacuum dryer. 2. The wire saw slurry management apparatus according to claim 1, further comprising a centrifugal separator.   5. The wire saw slurry management apparatus according to claim 4, wherein the centrifuge is provided in a plurality of stages.

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