KR20110007530A - Method and aparatus for drying sludge - Google Patents

Abstract

PURPOSE: A slugger drying method and a device, capable of reducing the costs for manufacturing and installing equipment by omitting a conveyor belt, is provided to prevent the fine particles from being agglomerated into clusters by drying the surface of slug. CONSTITUTION: A slugger drying method is as follows. A drying space(S) including hot air and microwave electromagnetic wave is prepared. The sludge is dropped to the location located lower than an inlet(28) of the drying space. The dropped sludge is placed on the higher location and is dropped again. The falling and rising of the sludge repetitively operate.

Description

Method and apparatus for drying sludge {Method and Aparatus for drying sludge}

The present invention relates to a method and apparatus for drying sludge, and more particularly, to a method and apparatus for drying by applying electromagnetic waves while floating in air in a space.

 In the semiconductor manufacturing process, when the silicon ingot is cut to produce a wafer or polished, a lot of waste slurries are used.

This waste slurry contains some cutting oil, silicon powder (Si), silicon carbide (SiC) and other foreign matter.

As such, a technology for separating and regenerating necessary materials from waste sludge generated in a semiconductor manufacturing process or the like is being developed.

As a technique for reclaiming waste slurry, a method and apparatus for recovering high purity high quality abrasive from waste slurry generated from semiconductor FAB process to CMP high quality polishing process are disclosed in Application No. 10-2002-0067603.

This technique is to mix the collected waste slurry with alcohol or thinner with 2-5% of nonionic surfactant and 0.5-3% of dispersant, and then to first stirring → reaction → second stirring → reaction → third stirring → washing separation → drying → classification.

Most of the collected slurry is a mixture of water-soluble oil and water with high-grade abrasives, Si, Fe 2 O 3 and other impurities, so that the water-soluble oil in the storage container is first pumped out and then the composite solidified in the cake state at the bottom. In the stirrer, the purified solution and the alcohol were added about twice as much as the solid, and the mixture was stirred and stored in a container. The reaction resulted in more separation than the pure alcohol alone. The ultra fine powder of the abrasive and the ultra fine powder of the Si component from the wafer are present in a ratio of about 50:50, and the intermediate layer has about 80 to 85% of the abrasive component and about 15 to 20% of the Si and Fe ₂ O ₃ components. Present in the form of medium particles, the lower layer is about 5-10% abrasive component, Si and Fe ₂ O ₃ The component appears in the form of relatively coarse particles of 90-95%. The upper layer and the lower layer are separately managed by using a mechanical device, and the solids of the middle layer are added again to the second stirrer by adding alcohol (B) containing a purification solution, and then stirred and stored in a container to react again. Becomes At this time, the intermediate layer has a high abrasive component of 90 to 95%. When the solids of the intermediate layer were added by stirring the alcohol (A) containing the purification solution into the tertiary stirrer (30), and then introduced into the washing equipment, the washing liquid (A) in ten dish-shaped pans made of STS material of the cleaning equipment. It is contained together with vibration, tilt rotation, eccentric rotation, etc., when the secondary agitation, the 90-95% abrasive purity of the intermediate layer is purified and separated into high purity of 99.9% or more and stored in the settling tank 41 during the second stirring. The product is separated into solids, and the purified solution is transferred to (B-1). The solids are passed through an indirect heating type dryer, and then put into a classifier in powder form, and then discharged into finished products by controlling the particle size for each use. In this case, high purity high quality abrasives can be recovered through the process by using anionic surfactant as a refining solution in alcohol, and during the process, complete separation of abrasives, waste oil, and Si and Fe ₂ O ₃ is not achieved. It is a way to regenerate and use high-quality abrasives that were used for low cement raw materials.

Other technologies include Korean Patent Registration No. 393007 (Name: Waste Slurry Regeneration Method and Regeneration System in Semiconductor Wafer Manufacturing Process), and Korean Patent Application Publication No. 10-2004-0055218 (Name: High Purity Silicon Carbide from Waste Semiconductor Slurry) Method of preparing the same).

Waste slurry recycling method generated in the semiconductor wafer manufacturing process presented in the Korean Patent Registration No. 393007, stirring the waste slurry to spread out the precipitate consisting of abrasives and cutting powder; A dilution step of mixing and diluting a recycled oil in the waste slurry stirred in the stirring step; A one-dimensional core separation step of extracting abrasives by first centrifuging the waste slurry in the dilution step; A second centrifugation step of performing a second centrifugation of the first oil discharged by the first centrifugation in the first dimensional centrifugation into a second oil and cutting powder; Filtration / purification step of filtering the secondary oil by filtration to reduce the regeneration oil; It is a regeneration method comprising a waste slurry regeneration step of regenerating the slurry by adding the abrasive extracted in the first centrifugation step prior to the regeneration oil purified in the filtration / purification step.

In addition, the waste slurry regeneration system generated in the semiconductor wafer manufacturing process includes: a stirring tank for agitating the introduced waste slurry to disperse deposits consisting of abrasives and cutting powder contained in the waste slurry; A dilution tank for mixing and diluting recycled oil to waste slurry introduced by stirring from the stirring tank; A primary centrifuge for extracting abrasives by first centrifuging the diluted waste slurry introduced from the dilution tank; A secondary centrifuge for secondary centrifugation with primary oil and cutting powder extracted from the first dimensional core and the abrasive is extracted; A filter for filtering / purifying the secondary oil from which the cutting powder is extracted in the secondary centrifuge to make recycled oil; A reconditioning tank for regenerating the regenerated slurry by adding the abrasive extracted by the primary centrifuge to the regenerated oil refined by the filter and regenerated.

In the waste slurry recycling method and the recycling system generated in the above semiconductor wafer manufacturing process, when the waste slurry solidified by long-term storage using the stirrer is spread out, the abrasive and the impurities attached to the abrasive are not dispersed and extracted with a centrifuge. Impurities adhere to the abrasives, which are disadvantageous in that they cannot extract abrasives of high purity.

In addition, the technique disclosed in Korean Patent No. 10-2004-0055218 discloses high-purity carbonization from waste semiconductor slurries generated during silicon wafer cutting and waste electrode slurry graphite powders from waste semiconductor slurries for producing silicon carbide for use in the polishing industry and structural materials. It relates to a method of producing silicon. In particular, high-purity silicon carbide is synthesized by the silicon carbonization method of the material generated in the cutting process of the silicon wafer which is a waste resource and the graphite rod generated in the waste battery at 1600 ° C or higher. Specifically, oil useful in the slurry generated during the cutting of the silicon wafer is separated by filtration, and the solid powder contains silicon, silicon carbide, copper, iron, or the like of about 1 to 12 µm. Among the solid powder, copper and iron are heavier than silicon and silicon carbide and have a specific gravity, so that they are easily separated and removed by specific gravity screening and magnetic screening, whereby only a solid powder containing silicon and silicon carbide can be obtained. In order to synthesize high purity silicon carbide from the above silicon and silicon carbide solids, the powders of silicon and silicon carbide solid powders produced from the slurry were calcined for 2 hours or more at a reaction temperature of 1600 ° C. or more using silicon carbide method. Can be synthesized and finely pulverized to obtain silicon carbide of high purity. In particular, the metallic silicon and silicon carbide, the silicon density of 2.33g / cm ^3, the density of the silicon carbide 3.22g / cm ³ because it is a heavy liquid can be selected, in which the main impurities like copper and iron carbide directly after the removal of impurities The method of synthesizing silicon is used. That is, impurities such as copper and iron can be easily removed by magnetic screening, specific gravity screening and pickling.

No. 10-0177139, registered November 17, 1998, discloses a "method for producing high purity silicon powder and silicon nitride powder from waste silicon." This is to obtain high-purity silicon nitride powder from the waste silicon sludge generated in the silicon wafer processing process in the manufacture of semiconductors, the top and bottom cut portions of the silicon ingot and / or the waste silicon wafer, and the waste silicon sludge is neutral solution, acid solution and alkaline solution. Washing each with; and filtering after each wash; Washing the resulting silicon powder with distilled water and then with alcohol, filtering after each wash; Drying the silicon powder; Classifying the silicon powder according to size; Nitriding the silicon powder by contact with a nitriding reaction gas. In order to obtain high-purity silicon nitride powder from the top and bottom cut-outs of silicon ingots and / or the waste silicon wafers, the top and bottom cuts and debris of silicon ingots, residual silicon crystals in the crucible, or the waste silicon wafer are divided into pieces of about 1 cm in diameter. Tea grinding; Washing the debris with distilled water and alcohol, and performing filtration after each wash; Drying the debris; Secondary grinding of the debris to obtain fine silicon powder; Classifying the silicon powder according to size; Contacting the silicon powder with a nitrogen reaction gas to nitrate.

Thus, although the prior art proposes various methods and apparatuses for obtaining high purity silicon or silicon carbide from a pessler, it is difficult to obtain satisfactory output.

In the present invention, "sludge" means that the fine particles are mixed with the liquid and become like porridge. Electromagnetic waves are microwave electromagnetic waves, which mean electromagnetic waves having a wavelength that is best absorbed by a liquid mixed with fine particles.

It is a primary object of the present invention to provide an apparatus and method for drying and powdering sludge containing silicon carbide.

A second object of the present invention is to provide a method and apparatus for drying and powdering sludge in which fine particles and fine particles of medicines, foods, metals, inorganics, organics, and the like are mixed with a liquid and precipitated.

The present invention is to provide a device for heating in a floating state using a microwave microwave.

The present invention allows the sludge containing fine particles to be temporarily floated in the inner space of the drum, and irradiated with electromagnetic waves to the sludge floating inside the drum so that the sludge is dried and powdered.

The present invention is a device for drying sludge containing fine particles, the drying space forming means having an inlet and an outlet, the drying space is formed therein, is installed inclined, and rotates a plurality of partitions therein; Hot air supply means for supplying hot air to the drying space, an electromagnetic wave supply means for supplying microwave electromagnetic waves to the drying space, and a transport means for supplying sludge to the inlet of the drying space and withdraw the dried fine particles to the outlet of the drying space; Include.

Drying space forming means, the drum having a plurality of partitions formed on the inner surface of the drum,

It comprises a drive means for rotating the drum, or is provided with a drum installed inclined, a rotating body formed with a plurality of partitions to rotate while contacting the inner surface of the drum, and a drive means for rotating the rotating body.

The hot air supply means includes a heating device for heating air, a cooling device for cooling the heated air to remove moisture, and a moving device for moving the heated air from the heating device to the cooling device after passing through the drying space. Include.

The electromagnetic wave supply means includes an electromagnetic wave generator for generating the microwaves and a waveguide for emitting the microwaves in a predetermined direction of the drying space.

The conveying means includes a dispensing apparatus having an input device for transferring the sludge to the inlet position of the drying space, and a hopper for receiving the fine particles dried at the outlet position of the drying space. Real screw feeders can be used.

The present invention is a method for drying the sludge containing fine particles, a preliminary step of preparing a drying space in which hot air and microwave electromagnetic waves exist, and dropping the sludge from a high position to a low position while moving from the inlet to the outlet of the drying space A step of raising the sludge dropped to a high position and falling back to a low position is repeatedly performed to obtain fine particles of dried sludge at the exit of the drying space.

In the preliminary stage, hot air and microwave electromagnetic waves are supplied to the drum inner space while rotating a drum having a plurality of sludge conveying partitions therein, or rotating a rotating body composed of a plurality of sludge conveying partitions inside a sealed and inclined drum. In the drying step, the sludge is supplied to the inlet of the drum at a constant rate, moved by the partition of the rotating body to the high position on the inner wall of the drum, and lowered by gravity to be heated by the microwave, and low position. The sludge that has fallen into the furnace is repeatedly raised to a high position by the rotating drum or the rotating body, and eventually reaches the outlet of the drum, and the evaporated water moves to the outlet of the drum together with the hot air. The finely dried fine sludge reached is discharged outside the drum. . The hot air exhausted from the outlet of the drum is dried, supplied to the inlet of the drum, and circulated.

The present invention is a method and apparatus that can dry and powder not only sludge containing silicon carbide but also sludge in which fine particles or fine particles such as pharmaceuticals, foods, metals, inorganics, organics, etc. are mixed with liquid and precipitated.

Heating the sludge made of fine particles with microwaves is evaporated and dried from the moisture on the surface, rather than only drying with hot air, thereby solving the problem of agglomeration of fine particles into lumps.

In addition, the powder of the agglomerated sludge has a phenomenon that the agglomeration is broken as the moisture evaporates inside, and the particles are broken, thereby making it easy to powder.

In order to dry the conveyor belt as in the prior art, a very long conveyor belt is required and the apparatus should be large. However, if the structure permits the application of electromagnetic waves while continuously dropping in the drum, the apparatus does not have to be long. It is possible to produce a compact. Therefore, the manufacturing cost of equipment is reduced, and installation cost and labor cost of operation personnel are saved.

In the case of silicon carbide in the prior art is dried by the drying heat, the particle size deformation is generated and thus a process for regrinding was required, this problem is solved.

By circulating the hot air, the thermal efficiency can be increased, and even when there is harmful gas contained in the sludge and evaporated or when fine dust is discharged together with the hot air, it does not cause pollution.

An embodiment of the present invention will be described with reference to the drawings.

1 is a cross-sectional view of the device and FIG. 2 is a cross-sectional view of the rotation.

The present invention is a device for drying and powdering sludge containing fine particles, supplying the drying space forming means, hot air supply means, electromagnetic wave supply means, sludge to the inlet of the drying space and the dried fine particles at the outlet of the drying space It has a means of withdrawal.

Drying space forming means is a plurality of partitions (21, 22) to accommodate the sludge inside the drum 10 is rotatably installed inside the drum circumference and the drum center is a drying space (S), which is a substantial part of the empty space have. The partition is formed with a small amount of sludge to form a small storage space to be carried from the low position to the high position according to the rotation of the drum, consisting of a horizontal partition 21 and a vertical partition 22, the scraper (23) ) Is attached.

Alternatively, the drying space forming means includes a drum 10 fixedly installed to be inclined, and a rotating body 20 formed of a plurality of partitions to be in close contact with the inner surface of the circumference of the drum. The rotating body 20 has a horizontal partition 21 in the rotational direction, and a vertical partition 22 in the axial length direction are connected to each other, and the partitions are divided into spaces to form a plurality of small spaces. It is. That is, small square spaces are formed like honeycombs and are designed to rotate in close contact with the inner surface of the drum. As can be seen in FIG. 2, a scraper 23 or blade, such as a spatula, which causes the sludge to be attached to the drum inner surface to be melted is attached to the end of the longitudinal partition 22. As shown in FIG. This scraper 23 is made of a thin thin film made of a flexible material, and is designed to effectively remove sludge adhered to the drum inner surface. And this rotating body 20 is rotated by a drive means. The drive means consists of a reduction gear motor 25, a bearing 24, a sprocket 26, and the like. In the vicinity of the central axis of the drum, the inlet 28 and the outlet 29 are open, and the packing is installed to block the outside of the drying space (S). The drum inlet introduces sludge, hot air and electromagnetic waves.

Hot air supply means 30 is hermetically coupled to the inlet to blow hot air into the inlet of the drum. The hot air supply means comprises a heater 31 and a fan 32, and heats the air drawn into the air inlet or outlet line 35 from the heater 31 and blows it into the drum through the fan. The hot air entering the inlet is drawn out with evaporated water vapor while heating the sludge in the drying space. The hot air containing this steam is discharged to the drum outlet 29 and discharged to the atmosphere. However, the discharged hot air is sucked into the fan 33, cooled to below the liquefaction temperature through the cooler 34, and then sent back to the inlet of the heater 31 to be circulated. In this way, the drying space inside the drum is preferably maintained at atmospheric pressure.

Electromagnetic waves supplied to the drying space are generated and supplied by the electromagnetic wave supply means 40. Electromagnetic waves are microwaves that are well absorbed by water as microwaves and efficiently heat water, and the electromagnetic wave generator 41 generates microwaves and transmits them to the waveguide 42. The outlet of this waveguide is positioned at the inlet of the drum to heat the sludge together with the hot air. It is preferable to set the irradiation direction so that the microwaves are irradiated to the center of the drying space so as to concentrate on the free-falling sludge. The electron generator includes a dummy loader 43 and a tuner 45.

The sludge is introduced into the drum inlet and transported to the drum outlet by the conveying means. The conveying means has a screw transfer device for the injector 52 and a screw transfer device for the drawer 54. The sludge is introduced into the hopper 51 for feeding of the screw feeder for pulling, pushed by the screw driver, and then introduced into the drying space. At the end of the drum, the dried sludge falls into a powder state, which is pushed out of the drum by a screw driver of the take-out screw transfer device when it is put in the recovery hopper 55. At this time, the dried sludge is dried into a complete powder or powder agglomerate and is completely powdered by being pushed by a screwdriver.

In this method, the sludge containing fine particles is dried and powdered using the above apparatus.

Waste sludge generated in wafer cutting, polishing, etc. is settled at the end of the process using the processes such as filtration process, pickling process, washing process, separation process, centrifugation process, metal separation process, etc. Si and SiC sludge are obtained in which silicon and silicon carbide are precipitated in water. This Si and SiC sludge is used as a starting material of the method of the present invention to regenerate Si and SiC powders.

First, hot air and electromagnetic waves are applied to the drying space as a preliminary step before introducing the sludge into the drying space. Once the process conditions are met, the screw feeder is activated to introduce the sludge.

Next, the sludge is continuously drawn in continuously, but the first introduced sludge is placed on the first thermal partition of the drying space, and then rotates to raise the sludge to a high position and then drop to a low position, and the sludge dropped is a drum or a rotating body. By falling to raise the position to a high position, this process is repeated. Since the drum is inclined, the sludge introduced into the first thermal partition falls to the second thermal partition when it falls from a high position. This is determined by the inclination of the drum. When the slope is gentle, the sludge introduced into the first thermal partition rises to a high position and falls when the 1.5 thermal partition (an intermediate position, that is, half of the first thermal partition and the second thermal partition) is dropped. Is returned to the first thermal partition and the other half falls to the second thermal partition. The inclination and rotational speed of the drum are designed in advance taking into account the throughput of the incoming sludge, the temperature of the hot air, the flow rate, the power of electromagnetic waves, and the water content of the sludge. Sludge attached to the inner wall of the drum is scraped off and dropped into the drying space.

The scraper is attached to the rotating body and described as rotating together, but in the drum rotary type, the scraper is fixed to the upper part, and the drum is rotated so that the sludge attached to the drum wall is removed to fall off.

When the drum rotates repeatedly and repeatedly from the first row partition to the last partition by the rotation of the drum, the recovery hopper is located at the last drop position, and thus is collected in the recovery hopper. The sludge is completely dried by hot air and electromagnetic waves until the last partition. This drying process is the same whether the drum rotation type or the rotary body rotation method of the embodiment of the present invention is the same, that is, the sludge is completely dried, leaving only Si and SiC fine particles. In addition, this drying process prevents the shape of the particle size deformation while the fine particles are heated.

Heating the finely divided sludge with microwaves has various effects. That is, when drying only with hot air, the fine particles are agglomerated by evaporating and drying from the surface moisture, but micro-electromagnetic waves generate heat inside, so even though the sludge is agglomerated, the fine particles are not agglomerated by the evaporated water vapor. It is very effective because it can be separated one by one.

At the end, these sludge powders are collected in the hopper, which is again pulled out by a screwdriver to promote powdering. The dried sludge powder may be further powdered according to its state.

It is advantageous in many ways to circulate the hot air in the drying step of the drying step. The hot air is heated to a temperature capable of evaporating water, and the hot air containing steam is cooled below the liquefaction temperature of the steam to condense the water into water, and the dry hot air from which the steam is removed is heated again by a heater. Since it is hotter than air, energy required for heating to a predetermined temperature is saved. In addition, since water condensed in the cooler has a high temperature, condensed water can be recovered to the drain line 37 to preheat air or sludge. In addition, when there is harmful gas contained in the sludge and evaporated or when fine dust is discharged together with hot air, waste gas treatment device is required because it causes pollution. And the capacity of the waste gas treatment system can be reduced, making it economical.

When the hot air is discharged to the atmosphere without circulating the hot air, fine particles included in the hot air to be exhausted may be recovered by using a deodorizing filter and a fine dust collector.

Condensate from the cooler can be used as coolant to cool the electromagnetic generator when the temperature is low.

1 is a view showing a longitudinal section of the apparatus

2 is a cross-sectional view of the rotation.

Brief description of reference numbers

S: Drying space

10: Drum 11: Drum Support 13: Drum Incline Support

20: partition rotating body 21: horizontal partition partition 22: vertical partition partition

23: scraper 24: bearing 25: reduction gear motor

26: sprocket 28: drum inlet 29: drum outlet

30: hot air supply means 31: heater 32, 33: blower (fan)

34: cooler 35: air exhaust line 36: valve 37: drain line

40: electromagnetic wave supply means 41: electromagnetic wave generator 42: waveguide

43: dummy rod 44: radio wave sealing member 45: tuner

50: conveying means 51: hopper 52 for input

54: ejector 55: recovery hopper

Claims (10)

As a method of drying the sludge containing fine particles, A preliminary step of preparing a drying space in which hot air and microwave electromagnetic waves are present, The drying step of heating from the inlet of the drying space to a low position from the high position to a low position, and dropping the sludge to a high position and dropping it again to a low position while heating with electromagnetic waves and hot air and moving to the outlet. Sludge fine particle drying method comprising. The method according to claim 1, In the preliminary stage, the hot air and microwave electromagnetic waves are supplied to the drum inner space while rotating the rotating body composed of a plurality of sludge conveying partitions inside the sealed and inclined drum. In the drying step, the sludge is supplied to the drum of the drum at a constant rate, moved to the high position through the drum wall by the partition of the rotating body, and is heated by the microwaves while falling to the low position by gravity, As the partition is rotated on the drum wall and ascends to the high position again, it eventually reaches the outlet of the drum, and the evaporated water moves to the outlet of the drum with hot air, and the complete drying reaches the outlet of the drum. The sludge fine particles drying method characterized in that the fine particles of the sludge is discharged to the outside of the drum. The method according to claim 2, The method of drying the sludge fine particles, characterized in that the hot air exhausted from the outlet of the drum is dried and supplied to the inlet of the drum and circulated. An apparatus for drying sludge containing fine particles, Drying space forming means having an inlet and an outlet, the drying space is formed inside, installed inclined, the space consisting of a plurality of partitions inside the rotating space, Hot air supply means for supplying hot air to the drying space; Electromagnetic wave supply means for supplying microwave electromagnetic waves to the drying space; And a conveying means for supplying the sludge to the inlet of the drying space and drawing the dried fine particles to the outlet of the drying space. The method according to claim 4, The drying space forming means, A drum having a plurality of partitions formed on the inner circumference of the drum, Sludge fine particle drying apparatus characterized in that it comprises a drive means for rotating the drum. The method according to claim 4, The drying space forming means, With inclined drums, A rotating body having a plurality of partitions rotating while contacting the inner circumferential surface of the drum; Sludge fine particle drying apparatus, characterized in that the rotating body comprises a drive means for rotating the rotating body. The method according to claim 4, wherein the hot air supply means, A chiller to remove moisture from the heated air, A heating device for heating the air cooled in the cooling device; And moving means for moving the air heated in the heating apparatus to the cooling apparatus after passing through the drying space. The electromagnetic wave supply means is a sludge fine particle drying apparatus, characterized in that it comprises a microwave generator for generating a microwave and a waveguide for emitting the microwave in a predetermined direction of the drying space. The method of claim 4, wherein the transport means, An input device for transferring sludge introduced from the sludge inlet to an inlet position of the drying space; And a discharge device having a recovery hopper for receiving the fine particles dried at the exit position of the drying space. Allowing the sludge containing particulates to temporarily float in the internal space of the drum, Sludge powdering method comprising the step of irradiating electromagnetic waves to the sludge floating in the drum to dry the sludge powdered. Means for temporarily floating sludge containing particulates in an internal space of the drum, Sludge powder forming apparatus comprising a means for irradiating the sludge floating in the drum with the electromagnetic waves to dry the sludge powdered.

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