JP6093566B2 - Waste liquid treatment equipment - Google Patents

Description

  The present invention relates to a separation device that separates liquid containing silicon waste into silicon waste and liquid.

  In the manufacture of silicon devices, the process of cutting a silicon ingot to form a silicon wafer, the process of polishing the silicon wafer, and circuits such as ICs and LSIs in a large number of areas arranged in a lattice pattern on the surface of the silicon wafer And each region is cut along a predetermined cutting line to form individual silicon chips. In these processes, water is used to cool, for example, a cutting blade, a processing point, a polished portion, or to flush away silicon scraps.

  Silicon scraps are fine particles and are contained in a suspended state in the waste liquid. On the other hand, in recent years, from the viewpoint of water reuse and silicon reuse, there has been a demand for a technology for separating waste liquid containing silicon waste into silicon waste and water not containing silicon waste. There are known a method of physically separating by a chemical method and a method of chemically separating using a chemical (for example, see Patent Document 1).

  However, the physical separation method has a problem that clogging occurs during filtration or silicon particles pass through. In particular, in the centrifugation method, the concentration of silicon particles with respect to moisture is too thin, and the efficiency of centrifugation may be poor. In addition, the chemical separation method has a problem that it is difficult to reuse the liquid (water) because the chemical is used. For this reason, a separation device that efficiently separates silicon waste and water into silicon waste by adsorbing silicon waste in the waste liquid using a silicon adsorption plate is used (see, for example, Patent Document 2).

JP-A-8-164304 JP 2012-024661 A

  However, in such a separating apparatus, silicon scraps are scraped off by the separator and silicon scraps are recovered. However, by repeating such recovery, the surface of the silicon adsorbing plate becomes rough and the amount of recovered silicon scraps is reduced. There is.

  The present invention has been considered in view of the above problems, and in a separation apparatus that separates waste liquid containing silicon waste into water that does not contain silicon waste and silicon waste, the waste liquid can be efficiently removed even when the separation time elapses. The purpose is to allow separation into water and water.

The present invention relates to a waste liquid treatment apparatus that separates waste liquid containing silicon waste into silicon waste and purified water that does not contain silicon waste, and a separation processing means that separates the waste liquid into purified water that does not contain silicon waste and silicon waste. And a recovery means for recovering silicon scraps separated by the separation processing means, and the separation processing means is arranged in the liquid tank at a plurality of equal intervals in the liquid tank and a liquid tank for storing the waste liquid, and is negative in the waste liquid. A positively charged silicon adsorbing plate for adsorbing charged silicon debris, a plurality of alternating negatively charged cathode plates facing the silicon adsorbing plate and spaced apart from the silicon adsorbing plate, and an upper portion of the cathode plate And an unloading section for unloading the supernatant liquid out of the liquid tank, and an electric field forming section for forming an electric field between the silicon adsorption plate and the cathode plate, with the silicon adsorption plate as the anode and the cathode plate as the cathode. The recovery unit includes a separation unit that separates silicon waste from the silicon adsorption plate, an adsorption plate moving unit that moves the silicon adsorption plate from the liquid tank of the separation processing unit to the separation unit, and a management unit that manages the silicon adsorption plate; The management means separates the adsorption time counting unit that counts the accumulated time that the silicon adsorption plate is energized and adsorbs silicon for each silicon adsorption plate, and the silicon adsorption plate that has accumulated the predetermined time A command unit that issues a command to separate the silicon scrap from the silicon suction plate by moving to the part, and a separation that counts and stores the number of times the silicon scrap is separated from the silicon suction plate by the separation unit for each silicon suction plate a frequency storage section, the silicon suction plate has reached a predetermined number of times is considered to be deteriorated by the separation of the separation count stored in separate count storage unit the silicon scrap Or provided with a determination unit for determining, characterized in that the separation number of silicon suction plate of the determination unit each comprising a notification unit that performs a notification when it is determined to have reached the predetermined number of times.

  In the waste liquid treatment apparatus according to the present invention, the number of times of separation of the silicon scrap from the silicon adsorption plate is counted and stored for each silicon adsorption plate, and the number of separations stored in the separation number storage unit is predetermined. A determination unit that determines whether or not the number of times has been reached, and a notification unit that performs notification when the determination unit determines that the number of separations of each silicon adsorption plate has reached a predetermined number. The silicon adsorbing plate that has reached the predetermined number of times can be judged as deteriorated and removed from the liquid tank, and waste liquid containing silicon waste can be efficiently separated into silicon waste and purified water in the long term. it can.

It is a perspective view which shows the internal structure of an example of a waste liquid processing apparatus. It is a disassembled perspective view which shows an example of the liquid tank of the state which fractured | ruptured partially, a silicon | silicone adsorption board, and a cathode plate. It is a sectional view showing a state of forming a electric field between the silicon suction plate and the cathode plate accommodated in the liquid tank. It is a flowchart which shows the content of the process in a waste liquid processing apparatus.

  A waste liquid treatment apparatus 1 shown in FIG. 1 includes a separation processing unit 2 that separates silicon waste and purified water that does not contain silicon waste, and a recovery unit 3 that collects silicon waste separated by the separation processing unit 2. ing.

  The separation processing means 2 includes a liquid tank 20 that is formed of an insulating member such as a synthetic resin and stores a waste liquid to be processed. In front of the liquid tank 20, a waste liquid storage tank 40 for storing waste liquid containing silicon waste is provided, and the waste liquid is introduced from the waste liquid storage tank 40 into the liquid tank 20 by a pump (not shown). As shown in FIG. 2, the liquid tank 20 is a container having an open top, and a groove 200 a that is long in the vertical direction is formed on the inner peripheral surface of the side plate 200 in the longitudinal direction.

  Silicon adsorbing plates 21 and cathode plates 22 are alternately inserted into the grooves 200a. A plurality of silicon adsorption plates 21 and cathode plates 22 are arranged at equal intervals.

  The silicon adsorption plate 21 is made of a conductive member such as copper or stainless steel, and a plurality of silicon adsorption plates 21 are arranged at equal intervals in the liquid tank 20. A pair of engaged pieces 210 are formed on the upper portion of the silicon adsorption plate 21 so as to protrude upward with a gap in the width direction. An engagement hole 211 that penetrates in the width direction of the silicon suction plate 21 is formed in the engaged piece 210.

  A plurality of cathode plates 22 are arranged opposite to the silicon adsorption plate 21 and spaced from the silicon adsorption plate 21. On the upper part of the cathode plate 22, a carry-out part 220 for carrying the supernatant liquid of the liquid tank 20 out of the liquid tank 20 is provided. The carry-out unit 220 includes a cylindrical suction pipe 221 extending in the width direction of the cathode plate 22. A plurality of suction ports 222 are provided in the side surface of the suction pipe 221 along the longitudinal direction. Further, a delivery port 223 is formed at one end. The suction pipe 220 can suck the supernatant liquid in the liquid tank 20 from the suction port 221 and carry it out of the liquid tank 20 from the delivery port 223.

As shown in FIG. 3, the silicon adsorption plate 21 inserted into the liquid tank 20 becomes the anode and positively charged is connected to the anode 50 of the composed electric field forming unit 5 from the DC power source, the cathode plate 22, DC since the cathode charged negatively is connected to the cathode 51 of the power source 5, the electric field is formed between the silicon adsorption plate 21 and the cathode plate 22. Since the silicon waste in the waste liquid is negatively charged, it repels from the negatively charged cathode plate 22 and is adsorbed by the positively charged silicon adsorption plate 22. Further, the delivery port 223 provided in the cathode plate 22 communicates with the feed pump 25.

  As shown in FIG. 1, the recovery means 3 includes a separation unit 30 that is disposed on the side of the separation processing means 2 and separates silicon scraps from the silicon adsorption plate 21, and a liquid tank of the separation treatment means 2. An adsorption plate moving unit 31 that moves from 20 to the separation unit 30 and a management unit 32 that is electrically connected to the silicon adsorption plate 21 and manages the silicon adsorption plate 21 are provided.

  The separation unit 30 includes a box-shaped separation container 301 having a slit 300 through which the silicon adsorption plate 21 can be passed on the upper surface and an opening at the bottom, a pair of scrapers (not shown) disposed inside the separation container 301, and a scraper And a rotation mechanism (not shown) for rotating the. The slit 300 is provided with a shutter 300 a that prevents foreign matter from entering through the silicon adsorption plate 21. The scraper is made of a synthetic resin having elasticity such as rubber, and positions the silicon adsorption plates 21 accommodated in the separation container 301 between them. The scraper is formed in a strip shape, and is provided so that the longitudinal direction is parallel to the width direction of the liquid tank 20. The scraper is driven and rotated by a rotation mechanism, so that the lower end of the scraper comes into contact with or separates from the surface of the silicon adsorption plate 21 accommodated in the separation container 301. The rotation mechanism rotates the central portion of the scraper around an axis parallel to the width direction of the liquid tank 20.

  A silicon waste tank 60 that stores the silicon waste recovered by the recovery means 3 is disposed below the separation unit 30. The silicon waste tank 60 is a container having an open top, is connected to the lower part of the separation unit 30, and stores silicon waste separated in the separation unit 30.

  Further, the separation unit 30 includes hydrogen gas discharge means 302 that discharges hydrogen gas generated from the silicon scrap stored in the silicon scrap tank 60 to the outside. The hydrogen gas discharge means 302 passes through the wall of the separation container 301 to communicate the inside and outside of the separation container 301 and open the inside of the separation container 301 to the atmosphere.

  Below the silicon waste tank 60, a weight meter 61 is disposed. The weigh scale 61 includes a known load cell and the like, measures the weight of the silicon waste tank 60, and outputs the measurement result to the management means 32.

  As shown in FIG. 1, the suction plate moving unit 31 is disposed above the liquid tank 20, and includes a holding unit 33 that holds the silicon suction plate 21, a lifting unit 34 that moves the holding unit 33 up and down, and a holding unit. A horizontal drive unit 35 that horizontally moves the unit 33 and the lifting unit 34.

  The holding unit 33 includes a base 330 having a nut therein and a pair of chuck cylinders 331 attached to the lower portion of the base 330. The chuck cylinder 331 is spaced in the width direction of the liquid tank 20. Arranged. The chuck cylinder 331 includes a cylinder main body 332 fixed to the base 330 and a pin 333 that can be moved out and in from the cylinder main body 332. The pin 333 is formed in a columnar shape that can be inserted into the engagement hole 211 of the engagement piece 210 formed in the silicon suction plate 21.

  The elevating unit 34 includes a vertical ball screw 340 extending in the vertical direction, a guide rail 341 disposed in parallel with the vertical ball screw 340, and a belt 342 that rotates the vertical ball screw 340 using a motor (not shown) as a drive source. In addition, the base 330 of the holding unit 33 is guided by the guide rail 341 and moved up and down by the belt 342 rotating the vertical ball screw 340. Since the chuck 330 331 attached to the base 330 is also moved up and down as the base 330 is moved up and down, the silicon suction plate 21 engaged with the pin 333 of the chuck cylinder 331 can be moved up and down.

  The horizontal drive unit 35 has a horizontal ball screw 350 extending in the longitudinal direction of the liquid tank 20, a guide rail 351 extending in parallel with the horizontal ball screw 350, and a nut screwed into the ball screw 350 inside, and suspends the lifting unit 34. A suspension portion 352 and a motor (not shown) that rotates the horizontal ball screw 350 are provided. The horizontal ball screw 350 is rotated by driving the motor, whereby the suspension portion 352 is guided by the guide rail 351 in the horizontal direction. It is configured to move. The horizontal ball screw 350 and the guide rail 351 have a length extending from the upper part of the liquid tank 20 to the upper part of the separating part 30, and the silicon adsorbing plate 21 held by the holding part 33 is liquidated by the horizontal movement of the suspension part 352. It can be moved from the tank 20 to the separation unit 30.

  The management unit 32 includes a CPU and a memory, and includes an adsorption time counting unit 320 that counts the accumulated time during which the silicon adsorption plate 21 is energized and adsorbs silicon for each silicon adsorption plate 21, and the accumulated time is predetermined. An instruction unit 321 for moving the silicon adsorbing plate 21 after the time to the separating unit 30 and issuing an instruction to separate the silicon scrap from the silicon adsorbing plate 21 to the adsorbing plate moving unit 31 and the separating unit 30, and the separating unit 30 A separation number storage unit 322 that counts and stores the number of times silicon dust is separated from the silicon adsorption plate 21 for each silicon adsorption plate 21, and a predetermined number of times the separation number stored in the separation number storage unit 322 has passed. A determination unit 323 for determining whether or not, and a notification unit 32 for notifying that when the determination unit 323 determines that the predetermined number of separations has passed. It is equipped with a door.

  A discharge unit 7 that discharges purified water from the liquid tank 20 is disposed in front of the liquid tank 20. The discharge unit 7 includes a supply pipe 70 disposed on the side surface of the liquid tank 20 and an open / close valve 71 connected to the supply pipe 70.

  Above the waste liquid storage tank 40, a purified water storage tank 41 for storing purified water separated by the separation processing means 2 and not containing silicon waste is disposed. The purified water storage tank 41 includes a tank main body 410, a defoaming inclined plate 411 for erasing bubbles in the purified water, and a plurality of supply ports 412.

  The defoaming inclined plate 411 is formed in a flat plate shape that is inclined in the vertical direction along the longitudinal direction of the tank body 410, and divides the tank body 410 into two upper and lower spaces. A gap for passing purified water is formed between the long side of the defoaming inclined plate 411 and the inner wall of the tank body 410.

  The supply port 412 supplies the purified water discharged from the discharge unit 7 to the tank body 410. The same number of supply ports 412 as the supply pipes 70 and the open / close valves 71 of the discharge unit 7 are provided. The supply port 412 passes through the upper part of the tank body 410.

  Below, operation | movement of the waste-liquid processing apparatus 1 comprised as mentioned above is demonstrated with reference to the flowchart of FIG.

In the waste water treatment apparatus 1, the electric field forming unit 5 shown in FIG. 3, to form an electric field between the silicon adsorption plate 21 and the cathode plate 22. On the other hand, waste liquid containing silicon waste generated in a polishing apparatus, a cutting apparatus, or the like is stored in a waste liquid storage tank 40 of the processing apparatus 1.

  When the open / close valve 71 is closed and the waste liquid in the waste liquid storage tank 40 is stored in the liquid tank 20, the waste liquid accumulates in the liquid tank 20, and the silicon adsorption plate 21 and the cathode plate 22 are immersed in the waste liquid. It becomes.

  When a predetermined amount of waste liquid accumulates in the liquid tank 20, all the open / close valves 71 are opened. By the time that all the open / close valves 71 are opened, silicon scraps having a negative charge are adsorbed by the silicon adsorption plate 21 that is positively charged. On the other hand, the purified water from which the silicon waste has been removed is sucked by the pump 25 from the suction port 222 disposed at the upper part of the cathode plate 22 shown in FIG. 3 and passes through the delivery port 223 to the supply port 412 shown in FIG. To the purified water storage tank 41 (step S1).

Adsorption time counting unit 320 constituting the management unit 32, for each silicon suction plate 21, counts the cumulative time adsorbed silicon energized anode 50 of the electric field forming unit 5 (step S2). When there is a silicon adsorption plate 21 whose cumulative time has passed a predetermined time, the command unit 321 moves the silicon adsorption plate 21 to the separation unit 30 to separate and remove silicon debris from the silicon adsorption plate 21. A command to the effect is output to the suction plate moving unit 31 and the separating unit 30 (steps S3 and S4). On the other hand, when there is no silicon adsorption plate whose accumulated adsorption time has passed the predetermined time, the separation process of silicon waste from the waste liquid is continued (steps S3 and S1).

  When a command to separate and remove silicon waste is output from the command unit 321, the horizontal ball screw 350 is rotated under the management of the management unit 32, so that the silicon suction plate 21 from which silicon waste is to be separated is rotated. The holding part 33 is moved immediately above. In this state, the holding part 33 is lowered by rotating the vertical ball screw 340, and the chuck cylinder 331 is positioned on the horizontal extension of the engaged piece 210 of the silicon suction plate 21.

  Next, the pin 333 of the chuck cylinder 331 is projected from the cylinder main body 332, whereby the pin 333 is inserted into the engagement hole 211 formed in the engaged piece 210 and engaged. Then, in this state, the vertical ball screw 340 is rotated in the reverse direction to raise the holding means 33, thereby pulling up the silicon adsorption plate 21 above the liquid tank 20.

  When the silicon adsorbing plate 21 is pulled up above the liquid tank 20, the open / close valve 71 on both sides of the pulled silicon adsorbing plate 21 is closed under the control of the management means 32, and the purified water storage tank 41 from there is closed. Stop feeding.

  Next, the suction plate moving unit 31 moves the holding unit 33 holding the silicon suction plate 21 directly above the separation unit 30 by rotating the horizontal ball screw 350. Then, the silicon adsorbing plate 21 is inserted into the separation container 301 through the slit 300 by rotating the vertical ball screw 340 to lower the holding portion 33. At this time, a pair of scrapers (not shown) provided in the separation unit 30 are in a parallel state with a space therebetween.

  After the silicon adsorbing plate 21 is lowered, the lower end portion of the scraper is brought into contact with the silicon adsorbing plate 21, and in this state, the vertical ball screw 340 is rotated in the reverse direction to raise the holding unit 33 and the held silicon adsorbing plate 21. As the silicon adsorbing plate 21 rises, silicon scraps are scraped off and separated by the scraper (step S5). The separated silicon waste is stored in the silicon waste tank 60.

  When the silicon adsorbing plate 21 from which the silicon scrap is separated ascends and is pulled up above the separating unit 30, the horizontal ball screw 350 is rotated in the direction opposite to that when the silicon adsorbing plate 22 is conveyed to the separating unit 30, The silicon adsorption plate 21 is moved to above the original storage location of the liquid tank 20. Then, the vertical ball screw 340 is rotated to return the silicon adsorption plate 21 to the original location of the liquid tank 20.

  The separation number storage unit 322 constituting the management means 32 secures a storage area for storing the number of separations of the silicon adsorption plate 21 for each silicon adsorption plate, and when step S5 is completed, the number of separations of the silicon adsorption plate 21 is completed. Is counted and stored in the separation number storage unit 322 (step S6).

  The determination unit 323 constituting the management unit 32 determines whether or not the number of separations stored in the separation number storage unit 322 has reached a predetermined number (step S7), and the number of separations has reached a predetermined number. If it is determined, the notification unit 324 notifies the operator to that effect (step S8). The silicon adsorbing plate 21 in which the number of separations of the silicon waste has reached a predetermined number is considered to have deteriorated due to the separation operation. Therefore, the silicon adsorbing plate 21 is removed from the liquid tank 20 and another silicon adsorbing plate is newly added. The waste liquid containing silicon waste can be efficiently separated into silicon waste and purified water over a long period of time.

  The weigh scale 61 measures the weight of the silicon waste tank 60, and when it reaches a predetermined weight, notifies the management means 32 of the fact, and the management means 32 notifies the fact from the notification means 324, so that the silicon The operator is urged to remove silicon waste from the waste tank 60.

  As described above, the waste liquid treatment apparatus 1 can be separated into silicon waste and purified water by the positively charged silicon adsorption plate 21 adsorbing silicon waste. Therefore, the waste liquid containing silicon waste can be made into a state where it can be reused efficiently.

  Further, when the accumulated time for adsorbing silicon debris reaches a predetermined time, the silicon debris is removed from the silicon adsorbing plate 21, so that the silicon debris can be removed at an appropriate timing before the adsorbing capacity is reduced. it can. In addition, since such management is performed for each silicon adsorption plate 21, the adsorption capability is always maintained for each silicon adsorption plate.

  Further, the number of separations is counted for each silicon adsorption plate, and for the silicon adsorption plate 21 in which the number of separations reaches a predetermined number, by notifying that fact, the deteriorated silicon adsorption plate is replaced with a new one. Therefore, waste liquid containing silicon waste can be efficiently separated into silicon waste and purified water in the long term.

1: Waste liquid processing apparatus 2: Separation processing means 20: Liquid tank 200: Side plate 200a: Groove 21: Silicon adsorption plate 210: Engagement piece 211: Engagement hole 22: Cathode plate 220: Discharge unit 221: Suction pipe 222 : Suction port 223: delivery port 25: pump 3: recovery means 30: separation part 300: slit 300 a: shutter 301: separation container 302: hydrogen gas discharge means 31: adsorption plate moving part 32: management means 320: adsorption time counting part 321: Command unit 322: Separation count storage unit 323: Judgment unit 324: Notification unit 33: Holding unit 330: Base 331: Chuck cylinder 332: Cylinder body 333: Pin 34: Lifting unit 340: Vertical ball screw 341: Guide rail 342 : Belt 35: Horizontal moving part 350: Horizontal ball screw 351: Guide rail 352: Suspension part 40: Waste Holding tank 41: purified water storage tank 410: Tank body 411: antifoaming inclined plate 412: supply port 5: electric field forming unit 50: anode 51: cathode 60: silicon waste tank 61: gravimeter 7: discharge section 70: feed Piping 71: Open / close valve

Claims (1)

A waste liquid treatment apparatus for separating waste liquid containing silicon waste into purified water not containing silicon waste and silicon waste,
The separation processing means for separating the silicon waste from the waste liquid and the purified water containing no silicon waste, and the recovery means for recovering the silicon waste separated by the separation processing means,
The separation processing means includes: a liquid tank for storing the waste liquid; a plurality of positively charged silicon adsorption plates that are disposed in the liquid tank at equal intervals and adsorb negatively charged silicon debris in the waste liquid; A plurality of negatively charged cathode plates arranged alternately and spaced apart from the silicon adsorbing plate, opposite to the silicon adsorbing plate, and a supernatant liquid disposed above the cathode plate to carry out the liquid tank. An unloading section, and an electric field forming section for forming an electric field between the silicon adsorption plate and the cathode plate, with the silicon adsorption plate as an anode and the cathode plate as a cathode,
The recovery unit includes a separation unit that separates silicon waste from the silicon adsorption plate, an adsorption plate moving unit that moves the silicon adsorption plate from the liquid tank of the separation processing unit to the separation unit, and the silicon adsorption plate Management means for managing
The management means separates an adsorption time count unit for energizing the silicon adsorbing plate and adsorbing silicon for each silicon adsorbing plate, and a silicon adsorbing plate after the predetermined time has elapsed. And a command unit that issues a command to separate the silicon scrap from the silicon adsorption plate, and counts the number of times the silicon scrap is separated from the silicon adsorption plate by the separation unit for each silicon adsorption plate. A separation number storage unit for storing, and a determination unit for determining whether or not the number of separations stored in the separation number storage unit has reached a predetermined number of times that the silicon adsorption plate is considered to have deteriorated due to separation of silicon debris. Has
A waste liquid processing apparatus comprising: a notification unit that performs notification when the determination unit determines that the number of separations of each silicon adsorption plate has reached a predetermined number.

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