KR101194188B1 - A method and an apparatus for recovering the active ingredient from wasted sludge of semiconductor and solar-silicon wafer manufacturing process - Google Patents

Abstract

PURPOSE: A method and an apparatus for collecting effective components from waste sludge are provided to collect vaporized components by charging and re-circulating inert gas. CONSTITUTION: A method and an apparatus for collecting effective components from waste sludge includes the following steps: waste sludge generated from a semiconductor solar-silicon wafer manufacturing process is introduced into a feed material hopper; the waste sludge is transferred to a primary drier charged with inert gas using a monoaxial or biaxial screw; the waste sludge is primarily dried using microwaves generated from a magnetron(3); vaporized components from the primarily drying operation is condensed; the dried waste sludge is dried using microwaves generated from a magnetron in a secondarily drier; vaporized components from a secondarily drying operation is condensed; and solid components are collected in a storing bath, and are packaged or transferred to a storing silo. [Reference numerals] (AA) Blower; (BB) Secondary condenser; (CC) Secondary condensate storing bath; (DD) Primary condensate storing bath; (EE) Storage tank; (FF) Storage tank; (GG) Raw material hopper; (HH) Primary condenser; (II) Secondary condenser; (JJ) Blower; (KK) Primary condensate storing bath; (LL) Secondary condensate storing bath; (MM) Primary condenser; (NN) Storage tank; (OO) Storage tank; (PP) Introducing feeder; (QQ) Primary dryer; (RR) Magnetron; (SS) Secondary dryer; (TT) Inert gas; (UU) Storage bath; (VV) Storage silo; (WW) Pulverizing/classifying unit

Description

A method and apparatus for recovering active ingredients from waste sludge produced in semiconductor and photovoltaic silicon wafers, and apparatus thereof.

The present invention relates to a method and apparatus for recovering active ingredients from waste sludge generated during semiconductor and photovoltaic silicon wafer manufacturing, and more particularly, to a multi-wire cutting process in a semiconductor and photovoltaic silicon wafer manufacturing process. From the used slurry containing cutting oil, abrasive (SiC), silicon (Si) powder and metal (mainly Fe) powder from multi-wire sawing, Microwaves in a dryer equipped with a magnetron that generates microwaves of high-viscosity waste sludge (containing cutting oil, abrasives (SiC), silicon powder, and metal powder) generated after the first recovery of cutting oil and finally disposed of as designated waste. Evaporate the cutting oil to recover with high purity, recover the dried solids, form into briquettes and recycle or By separating the recovered dried solids by component and recycling them as industrial materials, it solves the environmental pollution problem fundamentally, simplifies the manufacturing process and maximizes energy efficiency, while maintaining high-purity silicon (Si) powder, abrasive (SiC), cutting oil, etc. The present invention relates to a method and an apparatus for recovering the active ingredients. In addition, waste sludge (cutting oil, etc.) generated in the diamond wire cutting process during the drying of the abrasive (SiC) recovered by the first centrifuge and the high purity recovery of the contained cutting oil or the semiconductor and solar silicon wafer manufacturing process. Similar types of sludge such as silicon powder and diamond) can be effectively recycled by the method of the present invention.

In general, a wafer manufacturing process uses a method of producing a plurality of wafers at low cost by simultaneously cutting a single crystal, polycrystalline or amorphous silicon ingot with multiple multi-wire saws. For cutting, a slurry in which silicon carbide (SiC), which is used as an abrasive, is dispersed in cutting oil (usually glycols) is used, and a dispersant and a surfactant are added to promote the dispersion of the abrasive. . When the wire is rotated while injecting the slurry configured as described above, the silicon ingot is pressed and cut. In this process, cutting powder of fine silicon particles such as sawdust is generated and mixed into the cutting oil. As cutting continues, the amount of cutting powder increases to 20-30% by weight or more, the viscosity increases, the efficiency decreases, the cutting state of the wafer changes, the surface of the wafer is deformed, and finally the slurry is changed. Cannot be used.

Therefore, conventionally, used sludge was disposed of as it is, or a portion of the cutting oil or abrasive material was recovered from the used slurry, and the remaining waste sludge was discarded. However, as the demand for silicon has exploded due to the environmental pollution problem and the high growth of the solar cell industry, technologies for recovering silicon from waste sludge have been studied, but mainly for the purpose of high purity recovery of silicon (Si). In order to purify (Si) with high purity, it has to go through a complicated separation and purification process, resulting in low productivity and an increase in manufacturing cost. In addition, developments have been made to improve the recovery of reusable abrasives (SiC) and cutting oil (containing fine powder). In recent years, processes using primary and secondary centrifuges that have significantly increased the recovery have been used, but are still disposed of. Waste sludge is generated in a large amount, and the amount of generation is also greatly increased as the production of the entire wafer increases due to the development of the solar cell industry.

The abrasive (SiC) recovered in the first centrifugal separator contains about 20% by weight of cutting oil, and only the recovered abrasive (SiC) containing the cutting oil cannot be used alone, and a new slurry and a certain ratio are used. The mixed oil is used for mixing, and the remaining cutting oil-containing abrasive (SiC) remains on the material resin, and the remaining amount of the recovered cutting oil-containing abrasive (SiC) is also disposed of, and the recovered fine-containing cutting oil is vacuum distilled. Although it is purified and recycled as cutting oil or recycled as an industrial material, it contains fine powder, so it is generated sludge containing fine powder after vacuum distillation, and this sludge is also disposed of.

In addition, after cutting the cutting oil through the centrifuge from the cutting oil, silicon powder and diamond-containing slurry during the semiconductor and solar silicon wafer manufacturing process (Diamond wire sawing) Waste sludge (containing cutting oil, silicon powder and diamonds) is also disposed of.

As a result, the centrifugal separation method is mainly used to recover the abrasive (SiC) and the cutting oil from the used slurry, and the vacuum distillation method is mainly used to purify the recovered cutting oil. There is no commercial example yet for the method of economically separating, recovering and recycling high-viscosity waste sludge remaining after recovering the active ingredient using one or both methods. The waste sludge has already been separated to the limit that can be separated from the centrifuge and has a very high viscosity as remaining residues, which has a property that cannot be separated and recovered by conventional centrifugation or vacuum distillation.

As a method for recycling the waste sludge, the cutting oil and dispersant components are removed using an organic solvent, and the metal components are removed by chemical treatment such as acid, and then the silicon (Si) powder and the abrasive (SiC) are separated by a heavy liquid separation method. Although there have been studies of high purity recovery, such a process has not been put to practical use due to the generation of secondary waste and a low productivity and a very high manufacturing cost.

Korean Laid-Open Patent Publication No. 10-2011-128066 includes a first impurity removal step of removing impurities including quartz that can be physically removed from waste silicon; A second impurity removal step of removing impurities remaining in the first impurity removal step using an aqueous solution of a material containing lithium (Li); A washing step of washing to recover silicon from the residue from which impurities are removed in the second impurity removing step; And a drying step of drying the silicon washed in the washing step; a method for recovering silicon from waste silicon has been developed, which is washed, dried, using physical and chemical methods to remove impurities. Sedimentation, fruit, quartz addition. There is a problem that the manufacturing process such as going through a process such as heating is complicated and occupies a lot of installation space.

Korean Patent No. 10-0542208 discloses a technology related to a reclaiming device for semiconductor wafer waste sludge. The above technique comprises a first mixer which receives sludge from a waste sludge storage tank and mixes it with a viscosity modifier, a first separator which receives sludge from the first mixer and separates solids and liquid phase, and is separated from the first separator. A second mixer for receiving solids and mixing with the solvent, a second separator for receiving solids from the second mixer and separating the SiC component and the Si component, and drying the SiC component and the Si component separated from the second separator The present invention relates to a regeneration apparatus for semiconductor wafer waste sludge including first and second dryers, and generally using a conventional centrifugal separation method, which is characterized by using a centrifugal separator or a gravity sedimentation separator. As separation method uses density difference, there is a limit to separation of cutting oil, etc. contained in waste sludge. have.

Korean Patent No. 10-10-1102697 discloses a technique for regenerating waste sludge generated during solar cell and semiconductor wafer manufacturing, but the above technique is a solid phase of silicon (Si) and silicon carbide (SiC). It is characterized by the use of metatungstate hydrate for the heavy solution used for centrifugation using the density difference of. Korean Patent Publication No. 10-2011-0111946 also applies a flocculant to the cutting oil for the first and second centrifugation methods. There is a problem that has been disclosed by using a separation technique to overcome the limitations of the prior art.

Domestic Patent No. 10-177139 Domestic Patent No. 10-0542208 Domestic Patent No. 10-0839465 Domestic Publication No. 10-2011-0111946

1. Title: Recovery of Na₂SiF and Acetic Acid from Waste Acids Generated during Semiconductor Wafer Manufacturing Process -Author: Kim Hyun Sang, Kim Ju Yeop, Lee Hyang Sook, Shin Chang Hoon, Kim Jun Young, Actor Geun, Kim Jong Kwan -Publisher: Korea Resource Recycling Society

In order to solve the above problems, the present invention is a working slurry containing cutting oil, abrasive (SiC), silicon (Si) powder and metal (mainly Fe) powder generated during semiconductor and solar silicon wafer manufacturing process Waste sludge produced after the first recovery of SiC and cutting oil from primary and secondary centrifuges, or cutting oil containing abrasive (SiC) recovered from primary centrifuge, in diamond wire cutting process The generated waste sludge is recovered in high purity by vaporizing cutting oil using microwaves in a drier equipped with a magnetron that generates microwaves, and recovered dried solids are formed into briquettes and recycled, or the solids are used as ingredients. It is manufactured while solving environmental pollution problem by recycling it to industrial materials by separating and purifying it with high purity To provide a method for recovering defined simplified and a high purity of the silicon (Si) powder and the abrasive material (SiC), cutting oil, and it is an object device.

In order to achieve the above object, the present invention is to recover the cutting oil and abrasives primarily in accordance with a conventional centrifugal separation method, and to recover the cutting oil, abrasives (SiC) and silicon from the waste sludge generated at this time, a microwave generator First drying in a drying apparatus attached. At this time, the first drying step undergoes a second drying step using heat obtained by absorbing microwave energy, and the components vaporized in the drying step are condensed in a condenser and recycled as cutting oil, as well as cutting oil ingredients dried by microwaves. The removed solids are recovered as it is and used as a briquette, or the solids are separated and recovered as silicon carbide (SiC) and silicon through a grinding / classifying apparatus and recycled as industrial materials. To this end, in particular, the drier is equipped with a magnetron, a microwave generator, to maximize energy efficiency and prevent the thermal deformation of cutting oil, which is easy to be thermally deformed, to recover high-purity cutting oil. Solid content absorbs microwave energy in the step and incorporates thermal energy By drying using the [mainly silicon carbide (SiC)] thermal energy of the, it is possible to efficiently remove the cutting oil components contained in silicon carbide (SiC) and silicon powder without consuming additional energy, and also microwave heating and silicon carbide ( The coolant component vaporized with the thermal energy possessed by the SiC) absorbed the microwaves was recovered with high purity without thermal deformation. In addition, in order to efficiently recover the vaporized cutting oil components, vaporized vaporized gases in the primary and secondary condensers are separated by condensation in the primary and secondary condensers, and contamination or vaporization of solids due to carbonization of the vaporized gases is carried out. In order to prevent deterioration of purity due to thermal deformation, the deterioration of purity was prevented by filling and recirculating inert gas such as N ₂ or CO ₂ in the dryer.

The present invention is capable of purifying and recovering cutting oil, silicon and silicon carbide from semiconductor and photovoltaic silicon wafer waste sludge with high purity, and by installing a magnetron as a microwave generator in the dryer to increase energy efficiency by drying the waste sludge with microwaves, Cutting oil, which is easy to be deformed, can be recovered without thermal deformation, thereby reducing manufacturing cost and recovering high-purity cutting oil, and filling and recirculating inert gas to prevent thermal deformation of the liquid component and contamination of carbon and solids, and to effectively evaporate the vaporized components. Recoverable, high-purity silicon carbide (SiC) and silicon can be recovered with high efficiency, and by cutting the condensation of the cutting oil vaporization without heat deformation, there is an effect to recycle the high-purity cutting oil. In addition, the same applies to sludges of similar type, such as drying of the abrasive (SiC) recovered by the first centrifugal separator and high purity recovery of the contained cutting oil, drying of the sludge generated in the diamond wire cutting process and high purity recovery of the cutting oil. have.

1 is a conventional process diagram for recovering crushed oil from waste sludge generated in a wafer processing process.
2 is a process diagram of the present invention for separating and recovering cutting oil and solids (abrasive material (SiC), silicon (Si) powder, metal powder) from waste sludge.
3 is a process diagram for separating and recovering the solid content (abrasive material (SiC), silicon (Si) powder, metal powder) recovered from the waste sludge for each component

DETAILED DESCRIPTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, but the following description is provided to illustrate the present invention, and the scope of the present invention is not limited to the following description. It is included in the scope of the invention.

In the present invention, for the sake of brevity of the description of the well-known technical parts will be omitted or compressed.

FIG. 1 is briefly described as a process in which waste sludge is finally generated after first recovering abrasive (SiC) and finely divided cutting oil from used slurry generated in a conventional silicon wafer processing process.

In the wafer manufacturing process, used slurry, which contains abrasives generated when cutting single crystal, polycrystalline or amorphous silicon ingot, and fine silicon particles such as cutting oil and sawdust, can be reused in the first centrifuge. The low-density fraction containing a large number of cutting oil components generated after the first centrifugal separation is a process of recovering cutting oil, which is a liquid powder containing a part of fine powder, and generating high-viscosity waste sludge. Consists of.

2 is a step of introducing waste sludge into the raw material hopper; Transferring the waste sludge introduced into the hopper into the primary dryer by using a uniaxial or biaxial screw attached to the bottom of the hopper; Continuously drying the waste sludge transferred to the primary dryer using microwaves; Condensing the components vaporized in the first drying step in a condenser; Secondary drying of the waste sludge is first drying the solids in the first drying step with the heat energy itself (mainly silicon carbide (SiC)) by absorption of microwaves; the components evaporated in the second drying step in the condenser Condensing step of transporting or storing the solids after the second drying step.

The waste sludge introduced into the raw material hopper 1 contains approximately 70% by weight of solids and 30% by weight of cutting oil, and is very difficult to handle due to its high viscosity and flowability, and the above solids are about 50 to 70 It contains about 40% by weight of silicon carbide (SiC), 20 to 40% by weight of silicon and about 10% by weight of metal (mainly Fe). The primary dryer 2 is provided with a magnetron 3 and a primary condenser 4 which are microwave generators. That is, the waste sludge transferred to the primary dryer is heated by the microwave generated from the magnetron, and the coolant component, which is a liquid component, is evaporated out of the sludge, resulting in short drying time, high productivity, and excellent energy efficiency. .

In the present invention, by heating the waste sludge using a magnetron that generates microwaves as a heating means, not only the energy efficiency can be maximized, but also it can be recovered by evaporation while preventing thermal deformation of the cutting oil that is easily subjected to thermal deformation, thereby recovering the cutting oil with high purity. There is an advantage to this.

In other words, when drying by heating outside the dryer using a heat source such as a burner or electric heater, the drying temperature is increased from the surface of the waste sludge as the temperature inside the dryer rises, so that the cutting oil trapped inside the waste sludge is completely dried for a long time. The cutting oil recovered by such a heating method has a disadvantage in that it cannot be recycled as it is recovered due to severe heat deformation resulting in dark brown color and odor.

In addition, the dried solid content may remain a heat-deformed oil component that does not volatilize well even at a high temperature, there is a risk that these liquid components may be contaminated by carbides generated by carbonization, the energy efficiency is very low, Because

In the present invention, the cutting oil component in the waste sludge in the primary dryer is vaporized by absorbing microwaves, and the vaporized components are condensed through the primary condenser 4 and the secondary condenser 5 to the storage tank 6 through the condensate storage tank. The stored, uncondensed gaseous components are recycled through the blower 7 into the dryer.

At this time, in order to prevent thermal deformation of the liquid powder and efficient recovery of the vaporization component, an inert gas 8 such as N ₂ or CO ₂ is filled and recycled in the dryer.

After passing through the primary dryer, the solids are again fed into the secondary dryer (2-1), and the magnetron (3-1) is installed in the secondary dryer to undergo the same drying process as the primary dryer.

In addition, the secondary dryer may be dried using only the thermal energy of silicon carbide absorbs microwaves in the first drying step without the magnetron 3-1. That is, the secondary dryer (2-1), unlike the primary dryer, does not add additional energy, and the solid energy (mainly silicon carbide (SiC)) that absorbs microwaves in the primary drying step absorbs the heat energy of the microwaves. Energy is saved by completely drying the waste sludge by vaporizing the remaining cutting oil component remaining in the waste sludge, and recovering the solid content from which the liquid component is completely separated.

The vaporized cutting oil parts are condensed in the primary condenser (4-1) and the secondary condenser (5-1) and stored in the storage tank (6-1) through the condensate reservoir, and the remaining uncondensed gas components are blower It is recycled into the dryer through (7-1). At this time, as in the first dryer, inert gas 8 such as N ₂ or CO ₂ is filled and recycled in the dryer to prevent thermal deformation of the liquid component and efficient recovery of vaporized components.

In addition, the solid dried in the secondary dryer is stored in a storage silo via the storage tank (9).

FIG. 3 relates to a pulverizer classifying apparatus. When the solids that have passed through the first and second dryers are separated by components and recycled into industrial materials, the solids are directly transferred from the storage tank 9 to the pulverizer. It is transported or stored in the storage silo 10, and transferred to the grinding classifier 11 as needed to classify the grinding.

The grinder classifies the solids according to specific gravity or particle size. In the coarse mill, the above-mentioned first and second dried solids are recovered as agglomerates in the form of agglomerates or aggregates. Before being sent to the grinding machine, it is coarsely ground to a size of about 3 mm and transferred to the grinding machine hopper. As the coarse pulverizer, a coarse pulverizer 102 is installed at the bottom of the coarse grinding hopper 101, which is commonly used for coarse grinding such as a conventional hammer mill, roller mill, pin mill, etc. The pulverizer 104 is installed in the pulverizer, and the pulverized solid component is separated into metal silicon and silicon carbide (SiC) by air flow classification using particle size and specific gravity in the classifier 105 and the cyclone 106. Afterwards it is packaged or transferred to a storage silo and stored.

In detail, the coarse pulverized solid is transferred to the pulverizer hopper 103 and quantitatively transferred into the pulverizer 104 through a transfer screw attached to the lower end of the hopper. Solids in the pulverizer are finely pulverized into particles having an average particle size of 5 microns to 15 microns, and a maximum particle size of 50 microns or less, and then transferred to the classifier 105. As the pulverizer, an air jet mill, an air classifying mill, a ball mill, or the like, is used.

The pulverized solids are flowed by the blower to the classifier, and small particles are pulled out and large particles fall down by the rotating classifying rotor in the classifier. Silicon (SiC) is about 80% by weight to 98% by weight can be used for the use of the usual silicon carbide, such as refractory raw materials, ceramic raw materials.

Particles exiting the classifier are transported to the cyclone 106 by air flow and rotated through the inner wall of the cyclone. Due to the difference in centrifugal force according to the particle size, the larger particles fall down and the smaller particles move through the cylinder installed inside the cyclone. Followed out. Particles falling down have an average particle diameter of 2 microns to 10 microns, and the silicon carbide (SiC) content is about 70% to 90% by weight, and similar silicon carbide (SiC) of similar purity, such as refractory raw materials and raw materials for general purpose sintered compacts, is used. Can be used for purposes. When the ultrafine particles exiting the cyclone are transported to the dust collector 107 by air flow, they are collected by the bag filter installed inside the dust collector, and the ultrafine particles collected are 40 wt% or more of metal silicon and 20 wt% of metal (Fe). Molded into briquettes by more than% it can be used in applications where conventional silicon-iron alloys are used.

Since the powder particles are all collected in the bag filter, the air exiting the bag filter is discharged to the atmosphere through the blower 108.

A process for recovering reusable abrasive (SiC) from a first centrifugal separator and a low specific gravity fraction containing a large amount of cutting oil generated after the first centrifugation. The process of recovering cutting oil, which is a liquid powder containing part of fine powder, and generating high-viscosity waste sludge through a secondary centrifuge is generally used.High-viscosity waste sludge generated at the last stage is classified as designated waste and disposed of in total. It is becoming. In order to recycle the waste sludge, the organic solvent is used to remove the cutting oil, and the metal is removed by chemical treatment such as acid. However, in such a process, secondary waste generation and productivity are very low, and the manufacturing cost is very high.

As a result of long researches on waste sludge in semiconductor and photovoltaic silicon wafers, the inventors of the present invention have simplifies the manufacturing process using microwaves, improves energy efficiency, prevents heat deformation of cutting oil components that easily undergo thermal deformation, and inert gases for efficient recovery of vaporized components. By using and recycling, high-purity cutting oil can be recovered from high-viscosity waste sludge, which is difficult to handle, and it is possible to separate and recover completely dried solids without contamination from liquid deformation or carbonization. It is possible to recycle metal silicon powder and silicon carbide (SiC) powder, which depend on total imports, by separating and recovering silicon carbide and silicon components in high purity and high yield through fine pulverization and classification process. By developing the present invention, semiconductor and solar silicon wafers By eliminating the generation of waste generated from the disclosure, there is an advantage of resolving the problem of environmental pollution and recycling waste resources.

1: raw material hopper 2: primary dryer
2-1: secondary dryer 3 and 3-1: magnetron
4 and 4-1: primary condenser 5 and 5-1: secondary condenser
6 and 6-1: Storage tanks 7 and 7-1: Blowers
8: inert gas 9: reservoir
10: storage silo 11: grinding / classifying device
101: coarse grinding hopper 102: coarse grinding machine
103: grinding mill hopper 104: grinding mill
105: classifier 106: cyclone
107: cyclone 108: blower

Claims (9)

Introducing waste sludge into the raw material hopper; Transporting the waste sludge introduced into the hopper into a primary dryer filled with an inert gas using a uniaxial or biaxial screw attached to the lower end of the hopper and drying the primary sludge using microwaves generated from the magnetron 3; Condensing the components evaporating in the first drying step; Drying the first dried waste sludge using microwaves generated in the magnetron 3 in a secondary dryer filled with an inert gas; Condensing the components vaporizing in the second drying step; Transferring the solids collected in the reservoir to a packaging or storage silo; Method for recovering the active ingredients from the waste sludge generated during semiconductor and solar silicon wafer manufacturing, characterized in that consisting of.
delete The method of claim 1,
Waste sludge generated during the manufacture of semiconductor and photovoltaic silicon wafers, wherein the condensate in the first and second drying stages is stored in the storage tank via the condensate reservoir and the uncondensed gas is recycled into the dryer through the blower. Method for recovering active ingredients from the product.
Introducing waste sludge into the raw material hopper; Transferring the waste sludge introduced into the hopper to the inside of the primary dryer using a uniaxial or biaxial screw attached to the lower end of the hopper and drying the primary sludge; Condensing the components evaporating in the first drying step; Second drying the first dried waste sludge; Condensing the components vaporizing in the second drying step; Transferring the solids collected in the storage tank to a storage silo or a pulverizer; Finely grinding the transferred solids with a grinder; Separating metal silicon and silicon carbide (SiC) by air flow classification using particle size and specific gravity difference; Packaging or storing separated metal silicon and silicon carbide (SiC), the method for recovering the active ingredients from the waste sludge generated during the manufacture of semiconductor and photovoltaic silicon wafer.
The method of claim 4, wherein
Method for recovering the active ingredients from the waste sludge produced during the manufacture of semiconductor and photovoltaic silicon wafer, characterized in that the first and second dryers are installed with a magnetron for generating microwaves.
The method of claim 4, wherein
A method for recovering active ingredients from waste sludge produced during the manufacture of semiconductor and photovoltaic silicon wafers, wherein the primary and secondary dryers are filled with an inert gas.
Apparatus for recovering active ingredients from waste sludge generated during semiconductor and solar silicon wafer manufacturing
A raw material hopper having a uniaxial or biaxial screw attached to the waste sludge;
A primary dryer provided with a magnetron and a condenser for drying the sludge conveyed from the raw material hopper;
A secondary dryer or magnetron equipped with a condenser for completely drying the solids conveyed from the primary dryer and a secondary dryer equipped with a condenser; Transfer and storage of airflow pulverizer / classifier to separate secondary dried solids into silicon and silicon carbide (SiC), and the packaging machine or cyclone installed below in classifier, cyclone and dust collector among crusher / classifier. Apparatus for recovering the active ingredients from the waste sludge generated during the manufacture of semiconductor and photovoltaic silicon wafer, characterized in that consisting of a storage silo.
The method of claim 7, wherein
The secondary condenser is installed to recondense the uncondensed gas in the primary condenser of the primary and secondary dryers, and the primary and secondary condensate are stored in the storage tank through the condensate reservoir and the remaining gas is Apparatus for recovering the active ingredients from the waste sludge generated during the manufacture of semiconductor and photovoltaic silicon wafer, characterized in that the configuration is recycled to the primary and secondary dryers respectively through a blower.
The method according to claim 7 or 8
An apparatus for recovering active ingredients from waste sludge produced during the manufacture of semiconductor and photovoltaic silicon wafers, wherein the primary and secondary dryers are filled with an inert gas.

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