WO2011078219A1 - Procédé de récupération de poudre comprenant du silicium purifié - Google Patents

Procédé de récupération de poudre comprenant du silicium purifié Download PDF

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WO2011078219A1
WO2011078219A1 PCT/JP2010/073124 JP2010073124W WO2011078219A1 WO 2011078219 A1 WO2011078219 A1 WO 2011078219A1 JP 2010073124 W JP2010073124 W JP 2010073124W WO 2011078219 A1 WO2011078219 A1 WO 2011078219A1
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silicon
containing powder
pickling
raw material
surfactant
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PCT/JP2010/073124
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Japanese (ja)
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毅 沢井
大輔 守谷
利基 白濱
仁俊 中村
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株式会社新菱
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/02—Silicon
    • C01B33/037—Purification

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  • the present invention relates to a method for recovering purified silicon-containing powder. Specifically, the present invention relates to a method for recovering purified silicon-containing powder from raw material silicon-containing powder containing silicon dioxide as an impurity.
  • High purity silicon is used in the semiconductor industry and the solar cell industry, but the final silicon is about 30% of the raw silicon ingot in the semiconductor industry and about 50% of the raw silicon ingot in the solar industry. The remainder is discarded as silicon-containing powder discharged in the processing process of silicon ingots and silicon wafers. Due to the recent expansion of the solar cell market and consideration for the global environment, it is desired to develop technology for recovering and reusing silicon from waste containing high-purity silicon for use in solar cells. Yes. As a method therefor, a method has been proposed in which the recovered silicon-containing powder is remelted and recycled to a silicon ingot raw material or the like.
  • processing is performed while supplying water alone or a mixture of water and water-soluble coolant or oil-based coolant for the purpose of cooling, protection of processing tools, and removal of grinding or cutting waste.
  • the silicon-containing powders discharged in these processing steps are all fine powders having a particle size of 0.1 ⁇ m to several tens of ⁇ m, are very active, and come into contact with oxygen, moisture or treated water in the air.
  • An oxide film made of silicon dioxide (SiO 2 ) is formed on part or all of the surface.
  • the above-mentioned silicon-containing powder is often contaminated with impurities such as coolant used in processing steps and worn metal derived from processing machines. Therefore, the recovered silicon-containing powder cannot be recycled as it is, and it is necessary to remove these oxide films and impurities before re-melting the silicon-containing powder to produce high-purity silicon.
  • the purification process of silicon-containing powder before re-melting involves pretreatment to remove the coolant using a detergent, etc., and removal of silicon oxide film and trace metals on the silicon surface by chemical reaction using chemicals, as well as silicon-containing powder. It is roughly divided into a recovery and purification process for recovering the product.
  • the raw material silicon-containing powder is dispersed in water, and the pickling step for removing silicon oxide film and trace metal impurities with an aqueous pickling solution, the washing step for washing with water, and the silicon-containing powder after washing are dehydrated.
  • the solid-liquid separation step and the drying step of drying the silicon-containing powder after the solid-liquid separation are performed in this order.
  • the surface of the silicon-containing powder is obtained by an aqueous solution for pickling using a mixed solution of hydrofluoric acid and an inorganic acid as a pickling step.
  • the oxide film is removed and iron, aluminum, calcium, and other substances are removed.
  • Patent Document 2 discloses an organic cation flocculant in waste water containing silicon-containing powder generated from a silicon wafer manufacturing process as a method for separating silicon-containing powder discharged from a silicon wafer or the like in a processing process. And a method of adding a polymer flocculant to separate into a supernatant and a precipitate.
  • the oxide film on the surface of the silicon-containing powder is dissolved and removed by the reaction shown in the reaction formula (1) with hydrofluoric acid.
  • reaction formula (2) A new metal silicon surface is exposed from the silicon-containing powder from which the oxide film has been removed in an aqueous hydrofluoric acid solution.
  • reaction formula (2) As a result, as represented by the following reaction formula (2), reoxidation is easily caused by the reaction between metal silicon and water, and at the same time, hydrogen gas is generated. Si + 2H 2 O ⁇ SiO 2 + 2H 2 (2) That is, the above reaction formula (1) and the above reaction formula (2) indicate that the mutual reaction continues continuously as long as hydrofluoric acid and water coexist in the reaction system. Thus, since silicon components are eluted by repeating the formation and dissolution of silicon dioxide, there is a problem that the silicon recovery yield is lowered.
  • the silicon-containing powder discharged in the processing process of the silicon wafer or the like which is the subject of the present invention, has a small particle diameter (about 0.1 ⁇ m to several tens of ⁇ m), it does not settle easily, and the oxide film is removed and the surface is removed.
  • the silicon-containing powder that has been hydrophobized is more difficult to settle, making it difficult to recover the silicon-containing powder after purification by solid-liquid separation.
  • some silicon-containing powder may float with the hydrogen gas generated by the reaction of the reaction formula (2), and may form a scum layer that is deposited and floated in a scum form on the refined processing solution.
  • the refining process requires a large reaction tank that allows for the amount of scum generated, and the operability of the refining process is impaired due to the effect of floating scum.
  • the amount of water is increased because water washing after acid washing cannot be performed efficiently, and the solid-liquid separation operation after water washing is remarkably deteriorated.
  • the particle size of the silicon-containing powder is as large as 20 ⁇ m to 100 ⁇ m, the occurrence of scum is suppressed during the purification treatment, and there is little possibility that the solid-liquid separation operation becomes difficult.
  • the fine particles of 0.1 ⁇ m to several tens of ⁇ m cannot be adapted because scum generation and solid-liquid separation operability are significantly deteriorated.
  • Patent Document 2 separates silicon-containing powder and moisture, but the recovered silicon-containing powder is simply aggregated and precipitated using an organic cation flocculant and a polymer flocculant. Since it is only separated and contains a large amount of impurities, it cannot be used as it is as a high-purity silicon raw material. Moreover, when the pickling process of patent document 1 is used together with the method of patent document 2 for removing impurities, it is impossible to consistently suppress the occurrence of scum and maintain the coagulation sedimentation effect from the pickling process to the water washing process. However, this is not always an appropriate method for industrial implementation.
  • the object of the present invention is to remove the surface oxides, metal impurities, etc. of the raw silicon-containing powder and avoid reoxidation of the silicon-containing powder surface during the purification, so that purified silicon can be recovered efficiently It is providing the collection
  • Nonionic surfactant having an HLB value of 11 or less and / or an anionic surfactant having an HLB value of 11 or less using a raw material silicon-containing powder whose surface is partially or entirely coated with silicon dioxide
  • the purified silicon-containing powder recovery method according to ⁇ 1> or ⁇ 2>, wherein the pickling aqueous solution contains a nonionic surfactant having an HLB value of 11 or less and hydrofluoric acid.
  • the nonionic surfactant having an HLB value of 11 or less is at least one selected from the group consisting of sorbitan, polyoxyethylene, glycerin fatty acid ester, and alkenyl succinic acid ester surfactants.
  • ⁇ 5> The purified silicon-containing powder recovery method according to any one of ⁇ 1> to ⁇ 4>, wherein the anionic surfactant having an HLB value of 11 or less is alkenyl succinic acid.
  • ⁇ 6> The method for recovering purified silicon-containing powder according to any one of ⁇ 1> to ⁇ 5>, wherein the aqueous pickling solution further contains one or more inorganic acids selected from the group consisting of hydrochloric acid and sulfuric acid. . ⁇ 7> Any of the above ⁇ 1> to ⁇ 6>, wherein the aqueous pickling solution further contains one or more compounds selected from the group consisting of C 5 to C 35 paraffins, azole derivatives and morpholine derivatives.
  • a method for recovering powder containing purified silicon according to claim 1. ⁇ 8> The purified silicon-containing powder recovery method according to any one of ⁇ 1> to ⁇ 7>, wherein the silicon-containing powder (c) is dried at 450 ° C. or higher in an inert gas atmosphere in the drying step.
  • the present invention suppresses the occurrence of scum during the purification process of raw material silicon-containing powder, and at the same time allows more efficient purification process by expressing the coagulation sedimentation effect, minimizing the oxidation of the silicon-containing powder surface during purification Therefore, it is possible to obtain a silicon-containing powder that can be reused as a high-purity silicon raw material.
  • a raw material silicon-containing powder whose surface is partially or entirely coated with silicon dioxide, a nonionic surfactant having an HLB value of 11 or less and / or an anionic surfactant having an HLB value of 11 or less.
  • a pickling step in which the surface of the silicon-containing powder is brought into contact with an aqueous solution for pickling containing an agent and hydrofluoric acid, and the silicon-containing powder (a) is washed, and the silicon-containing powder (a) is washed with water
  • the silicon-containing powder (b) is washed with water, the silicon-containing powder (b) is solid-liquid separated, the silicon-containing powder (c) is solid-liquid separated, and the silicon-containing powder (c) is dried.
  • Process, And a purified silicon-containing powder recovery method hereinafter sometimes referred to as “recovery method of the present invention”).
  • raw material silicon-containing powder means silicon-containing powder as a raw material before purification
  • purified silicon-containing powder means silicon-containing powder purified through the steps according to the present invention.
  • silicon-containing powder (a) means a raw material silicon-containing powder processed in the pickling step
  • silicon-containing powder (b) means silicon-containing powder (a) in the water-washing step. This means a treated product
  • silicon-containing powder (c) means a product obtained by treating the silicon-containing powder (b) in the solid-liquid separation step.
  • the “raw material silicon-containing powder” that is the target of the recovery method of the present invention is one that is coated with an oxide film made of silicon dioxide that is discharged mainly in the processing process of high-purity silicon in the semiconductor industry and the solar cell industry.
  • this “raw material silicon-containing powder” refers to peripheral grinding powder generated when grinding and molding the outer periphery of a cylindrical silicon ingot in the semiconductor industry, when slicing a silicon ingot into a silicon wafer.
  • These raw material silicon-containing powders include those containing abrasive grains (SiC) generated when slicing is performed using free abrasive grains (silicon carbide: SiC).
  • the recovery method of the present invention is effective when the volume average particle diameter of the raw material silicon-containing powder is 0.1 ⁇ m to 20 ⁇ m, and particularly effective when it is within the range of 0.1 ⁇ m to 10 ⁇ m. This is because the silicon-containing powder having such a particle size (including the raw silicon-containing powder and the silicon-containing powder during and after purification) is extremely difficult to settle naturally in the liquid. It is difficult to recover the silicon-containing powder, and since the specific surface area of the silicon-containing powder is large, the surface is easily oxidized, and as a result, the oxygen content per unit weight of the purified silicon-containing powder after purification treatment increases. It is to do.
  • the raw material silicon-containing powder discharged in the semiconductor industry and solar cell industry described above has a small particle diameter, and in most cases, part or the whole of the surface is covered with an oxide film made of silicon oxide and used in the processing process. In some cases, it is contaminated with metal impurities derived from cutting jigs, grindstones, coolants, waste water treatment agents and the like. Therefore, it is necessary to remove these oxide films and metal impurities from the raw material silicon-containing powder before remelting and producing high-purity silicon.
  • the raw material silicon-containing powder contains an oil component such as a mineral oil-based coolant
  • a step of removing the oil component by a method such as evaporation or cleaning using an organic solvent or a detergent is further performed as a pre-step of the pickling step. It is preferable to provide it.
  • the raw material silicon-containing powder discharged in the semiconductor industry and solar cell industry which is the subject of the present invention, contains impurities shown below on the basis of the solid content of silicon-containing powder, depending on the background of its generation. It is normal. (1) Oxygen content (total oxygen) 4-10% by weight (2) Metal impurities (Fe etc.) 0.1-5% by weight (3) Carbon content 0.1-1% by weight The total oxygen is the oxygen content (% by weight) per unit weight of the silicon-containing powder.
  • the concentration of the raw material silicon-containing powder in the pickling step when it is brought into contact with the aqueous solution for pickling is not particularly limited.
  • the total amount of the raw material silicon-containing powder and the aqueous solution for pickling is 100% by weight, usually 5 to 40% by weight. It is preferably 10 to 35% by weight. Less than 5% by weight is not preferable because productivity is low. If it exceeds 40% by weight, the fluidity is deteriorated, the removal of silicon dioxide becomes insufficient, and the oxygen concentration in the purified silicon-containing powder after recovery may increase, which is not preferable.
  • this pickling aqueous solution not only can the generation of scum derived from silicon re-oxidation in the pickling step be suppressed, but also in the subsequent water washing step due to the effect of promoting aggregation of the silicon-containing powder as described later.
  • Oxidation (and generation of hydrogen) is repeated, but when the pickling aqueous solution according to the present invention is used, the surfactant is adsorbed on the surface of the raw silicon-containing powder after the oxide film is removed, and the silicon-containing Since the contact between the surface of the powder and water is inhibited, the reaction of the above reaction formula (2) does not proceed. Therefore, it is presumed that reoxidation of the raw silicon-containing powder from which the oxide film has been removed and generation of hydrogen gas are suppressed.
  • the surface of the raw material silicon-containing powder covered with the oxide film is hydrophilic, while the surface of the raw material silicon-containing powder after the oxide film is removed is hydrophobic. Therefore, it is considered that the surfactant orients the lipophilic group with respect to the surface of the hydrophobic raw material silicon-containing powder after the oxide film is removed, and the hydrophilic group exists outside. If a surfactant having a low HLB value of 11 or less is selected here, the hydrophilic groups of the surfactant are associated with each other while the hydrophobic groups are oriented to form micellar aggregates. It is presumed that the raw material silicon-containing powder after the oxide film is removed is prevented from being oxidized and coagulation sedimentation is promoted.
  • nonionic surfactant having an HLB value of 11 or less examples include sorbitan, polyoxyethylene (POE), glycerin fatty acid ester, and alkenyl succinate.
  • sorbitan for example, sorbitan trioleate, sorbitan monooleate, sorbitan monolaurate and the like can be mentioned.
  • polyoxyethylene (POE) for example, POE (EO: 2 mol addition) alkyl (C: 12) ether , POE (EO: 3 mol addition) alkyl (C: 12 to 13) ether, POE (EO: 5 mol addition) alkyl (C: 11 to 15) ether, and the like.
  • alkenyl succinic acid ester type examples include alkenyl succinic acid half ester and alkenyl succinic acid diester. These may be used alone or in combination of two or more. Good. Among these, sorbitan monooleate, POE (EO: 5 mol addition) alkyl (C: 11 to 15) ether, alkenyl succinic acid half ester, and alkenyl succinic acid diester are preferable.
  • anionic surfactant having an HLB value of 11 or less examples include alkenyl succinic acid and derivatives thereof. Among these, alkenyl succinic acid is preferable.
  • the concentration of these surfactants is determined in consideration of the amount of raw material silicon-containing powder, which is a solid content, the particle size, and the like. It is 5 to 20% by weight, preferably 1 to 10% by weight. If the concentration of the surfactant is less than 0.5% by weight, the surface of the raw material silicon-containing powder cannot be sufficiently coated, and if it exceeds 20% by weight, the chemical cost increases and the number of washings and the waste liquid treatment cost increase. Therefore, it is not preferable.
  • These surfactants only need to be sufficiently in contact with the raw material silicon-containing powder in the pickling step, and the method is not particularly limited. For example, the surfactant may be added after bringing an aqueous solution containing only hydrofluoric acid into contact with the raw material silicon-containing powder.
  • hydrofluoric acid and the raw material silicon-containing powder are contacted. It is preferable to add a surfactant before or simultaneously.
  • the pickling aqueous solution preferably contains one or more inorganic acids selected from the group consisting of hydrochloric acid and sulfuric acid as an acid component other than hydrofluoric acid.
  • inorganic acids selected from the group consisting of hydrochloric acid and sulfuric acid as an acid component other than hydrofluoric acid.
  • impurity elements such as Group 4 to Group 13 in the long-period periodic table can be effectively removed.
  • hydrochloric acid when a large amount of impurity elements belonging to Group 11 is contained, it is desirable to include hydrochloric acid.
  • the amount of inorganic acid added varies depending on the type and amount of metal impurities contained in the raw material silicon-containing powder and the concentration of coexisting hydrofluoric acid, but usually in the pickling treatment liquid containing the raw material silicon-containing powder. Concentration ranges from 0.1% to 20% by weight (in terms of pure amount).
  • one or more compounds selected from the group consisting of C 5 to C 35 paraffins, azole derivatives and morpholine derivatives (hereinafter sometimes referred to as “additives”). It is preferable to contain. By containing these compounds (additives), the agglomeration effect of the raw silicon-containing powder during pickling can be further increased, and the floc sedimentation rate can be shortened. Although the action of these compounds (additives) is not completely clear, it is presumed that they are manifested by adsorbing on the surface of the raw material silicon-containing powder during pickling due to the interaction with the surfactant. The addition amount of these additives varies depending on the addition amount of the surfactant, but is usually in the range of 0.05% by weight to 30% by weight in the concentration in the pickling solution containing the raw material silicon-containing powder. .
  • additives include normal paraffins, branched paraffins, monocyclic cycloparaffins, bicyclic cycloparaffins, polycyclic cycloparaffins, monocyclic aromatic hydrocarbons, as C 5 to C 35 paraffins.
  • Bicyclic aromatic hydrocarbons, polycyclic aromatic hydrocarbons, condensed polycyclic cycloparaffins, condensed polycyclic aromatic hydrocarbons and the like can be mentioned.
  • azole derivatives include benzotriazole-based 1,2,3-benzotriazole and benzothiazole-based 2-mercaptobenzothiazole.
  • morpholine derivatives examples include morpholine, thiomorpholine, ifosfamide, oxazine, and benzophenoxazine.
  • C 5 -C 35 paraffin, 1,2,3-benzotriazole, and morpholine are preferable, and C 16 -C 22 paraffin is particularly preferable.
  • additives can be removed from the surface of the silicon-containing powder by performing a heat treatment at 450 ° C. or higher in an inert gas atmosphere in the drying step described later in the same manner as the surfactant described above.
  • the treatment temperature in the pickling step is usually room temperature to 90 ° C, preferably 40 ° C to 80 ° C.
  • the reaction time may be appropriately set depending on the amount of silicon dioxide contained in the raw material silicon-containing powder, but is usually 1 to 3 hours.
  • This stationary separation method also has an advantage that the agglomeration of the silicon-containing powder (a) is difficult to break and the cohesiveness can be continued, so that the transition to the solid-liquid separation in the subsequent process becomes easy.
  • the silicon-containing powder (b) is dehydrated by solid-liquid separation in the next step to form a dehydrated cake.
  • the “dehydrated cake” is obtained by dehydrating the silicon-containing powder (b) after washing by solid-liquid separation, and silicon-containing powder (silicon-containing powder (c)) as a solid content obtained by solid-liquid separation.
  • it may contain water that remains in the dehydration process, surfactants, additives, and the like that cannot be completely removed.
  • a method of solid-liquid separation methods such as suction filtration, pressure filtration, and centrifugation can be applied.
  • Suction filtration or pressure filtration is preferable from the viewpoints of apparatus cost and dehydration efficiency.
  • cleaning liquid pH 5 or more by water-washing.
  • the dehydrated cake after the solid-liquid separation is dried in the next drying step to become purified silicon-containing powder for silicon reuse.
  • the drying method may be any of natural drying, air drying, heat drying, and reduced pressure drying, but heat drying is preferable for efficiently removing the surfactant added during pickling.
  • the drying atmosphere is preferably performed in an inert gas atmosphere such as argon or nitrogen in order to prevent reoxidation.
  • it is necessary to dry at a high temperature for the purpose of removing organic substances such as the surfactant after drying for the purpose of removing water. In this case, for example, it is preferable to perform drying by heating at a temperature of 450 ° C. or more for 1 to 3 hours.
  • Raw material silicon-containing powder concentration adjusting step In the recovery method of the present invention, hydrofluoric acid and an inorganic acid are used as components of the pickling aqueous solution, and the raw material silicon-containing powder may be treated while being heated.
  • the material of the processing equipment is selected in consideration of the corrosion resistance and heat resistance with respect to the chemical solution and the processing temperature. Examples thereof include a resin-based material such as fluororesin, polypropylene, polyethylene, and hard vinyl chloride, or a treatment tank or container with a stirrer that is lined with these materials.
  • the purification process involves the generation of hydrogen gas due to the reaction formula (2) and the reaction between metal impurities and inorganic acids, the treatment tank, exhaust line, exhaust gas equipment, etc.
  • a predetermined amount of ion-exchanged water is charged into a treatment tank and stirred.
  • a predetermined amount of the raw material silicon-containing powder is charged at room temperature, and mixed and dispersed under stirring to prepare a slurry concentration adjusting liquid for the raw material silicon-containing powder.
  • the form of the raw material silicon-containing powder varies depending on the discharge process, but may be any of powder, sludge, and slurry.
  • Step of adding surfactant and additive a predetermined amount of surfactant and additive are continuously added to the slurry concentration adjusting solution of the raw material silicon-containing powder at room temperature under stirring, for a predetermined time, Stir to disperse them uniformly.
  • the order of addition of the surfactant and the additive is not particularly limited, and either may be first.
  • Step of adding hydrofluoric acid and inorganic acid Gradually add predetermined amounts of hydrofluoric acid and inorganic acid to the raw material silicon-containing powder slurry to which the surfactant and additive are added at room temperature under stirring. Added. At this time, since heat is generated due to the reaction heat and dilution heat in the above reaction formula (1), it is preferable to gradually add the slurry liquid temperature below the pickling temperature described later. Either the hydrofluoric acid or the inorganic acid may be added in any order, but it is preferable to add hydrofluoric acid first in order to remove the oxide film on the surface of the raw material silicon-containing powder preferentially. In addition, when the heat generation is intense, it is preferable to control the slurry liquid temperature within a predetermined temperature range by external cooling.
  • the purpose of the pickling treatment is to remove the surface oxide film of the raw silicon-containing powder and to remove metal impurities, and the processing operation includes the raw silicon containing powder / surfactant / additive /
  • the processing operation includes the raw silicon containing powder / surfactant / additive /
  • these removal objects are solubilized and eluted to the water layer side.
  • Heating is preferably performed to increase the removal efficiency, and the heating method may be an external heating method, a submerged coil method, a jacket method, or the like, and is not particularly limited.
  • the treatment temperature and time depend on the treatment concentration of the raw silicon-containing powder, the amount of impurities contained, the concentration of the pickling solution, etc., but the conditions under which impurities such as the target oxide film and metal can be removed may be appropriately determined. However, a treatment at 40 to 80 ° C. for 1 to 3 hours is usually sufficient.
  • the cooling method may be selected as appropriate, such as an external cooling method, a submerged coil jacket method, or a water dilution method, and is not particularly limited.
  • Examples of the water washing method include a stationary hanging washing method and a forced replacement method. When the stationary hanging washing method is adopted, a supernatant liquid outlet is provided at a predetermined interval on the side surface of the processing tank.
  • a processing tank equipped with equipment such as a vertically movable extraction pipe capable of sucking and extracting the supernatant liquid from the upper part of the processing tank is used.
  • the operation method of the stationary hanging washing method is that the silicon-containing powder is settled by standing, and after the clear supernatant layer is extracted out of the system, ion-exchanged water is newly added and stirred, and then the standing operation is repeated. Thus, impurities, hydrofluoric acid, and inorganic acid dissolved in the aqueous solution are removed.
  • Solid-liquid separation process In the case of the above-mentioned stationary hanging washing method, the solid-liquid separation is performed by filtering the sedimented layer after the final stationary separation using a filter press or Nutsche etc. in the same manner as the forced displacement method. Finally, a dehydrated cake with reduced water content is obtained by pressing or the like.
  • the solid-liquid separation method is not particularly limited as long as a dehydrated cake can be obtained, and may be appropriately selected from a filtration method, a centrifugal separation method, a spray drying method, a rotary kiln method, and the like.
  • the dehydrated cake may contain a surfactant or an additive that cannot be completely removed in the water washing step.
  • Drying process The drying equipment is not particularly limited as long as an inert gas such as argon or nitrogen can be vented and the temperature range from room temperature to 500 ° C. can be controlled. , Vibration fluid dryer, conical dryer and the like.
  • the drying equipment After drying, the drying equipment is allowed to cool or cool to a temperature of 60 ° C. or lower, and then the purified silicon-containing powder is taken out. Then, it is put into a bag-like film packaging material that can be sealed, and the gas phase portion is replaced with an inert gas such as argon or nitrogen to seal it. During this sealing operation, vacuum packaging may be used.
  • air oxygen
  • the raw material silicon-containing powder, surfactants, additives, other chemical substances, experimental equipment, analyzers, and medium-scale prototype equipment used are as follows.
  • Table 1 shows the composition and impurity content of typical raw silicon-containing powders used in Examples and Comparative Examples, and FIGS. 1 to 5 show volume particle size distributions.
  • Table 2 Table 3, and Table 4 show the raw material silicon-containing powders, surfactants, additive types, and pickling solution concentrations used in Examples and Comparative Examples.
  • the types of surfactants are indicated by the following abbreviations.
  • Polymer flocculant ⁇ Polymer cationic flocculant: PVAD6450 (manufactured by Daianitrix)
  • Example 1 Into a 0.5 L polypropylene reaction vessel, 31 g of ion-exchanged water was placed, and set in a water bath and charged with raw material silicon-containing powder A: 56 g (solid content: 54.1%) at room temperature while stirring for another 30 minutes. Stirring was continued to obtain a slurry liquid in which the silicon-containing powder was uniformly dispersed. A surfactant (N4: POE (2) alkyl (C12) ether: 3.0 g) was added to this under stirring and dispersed by stirring for 5 minutes. Subsequently, 10% of 20% hydrofluoric acid: 10 g was gradually added within the range of the acid treatment set temperature or less while paying attention to the temperature rise and the foaming situation.
  • N4 POE (2) alkyl (C12) ether: 3.0 g
  • the raw material slurry concentration in the acid treatment liquid is 30%, the surfactant is 3.0%, and the HF is 2%.
  • this slurry solution was suction filtered using a polypropylene nutche and taken out as a dehydrated cake.
  • the dehydrated cake was dried by holding at 500 ° C. for 2 hours under a nitrogen atmosphere using a dryer to obtain a purified silicon-containing powder. The results are shown in Table 2.
  • Example 3 The same operation as in Example 1 was performed except that 3.0 g of N6: POE (5) alkyl (sec-C11-15) ether was used as the surfactant. The results are shown in Table 2.
  • Example 4 The same operation as in Example 1 was carried out except that N2: sorbitan trioleate: 1.5 g as a surfactant, 1.5 g of T5: benzotriazole (BTA) as an additive, and drying conditions at 450 ° C. .
  • BTA benzotriazole
  • Example 5 The same operation as in Example 1 was performed except that 1.2 g of N2: sorbitan trioleate was used as the surfactant, 1.8 g of T2: paraffin (C9-22): 1.8 g was used as the additive, and the drying condition was 450 ° C. It was. The results are shown in Table 2.
  • Example 6 The same operation as in Example 1 was performed except that 1.2 g of N3: glycerol monooleate was used as the surfactant, 1.8 g of T2: paraffin (C9-22): 1.8 g was used as the additive, and the drying condition was 450 ° C. It was. The results are shown in Table 2.
  • Example 7 The same operation as in Example 1 was performed except that 1.5 g of N1: sorbitan monooleate was used for the surfactant, 1.5 g of T6: morpholine: 1.5 g for the additive, and the pickling temperature was 60 ° C. The results are shown in Table 2.
  • Example 8 The same operation as in Example 1 was performed except that 1.5 g of N1: sorbitan monooleate was used as the surfactant, 1.5 g of T5: benzotriazole (BTA) as the additive, and the pickling temperature was 60 ° C. It was. The results are shown in Table 2.
  • Example 9 The same operation as in Example 1 was performed except that 1.2 g of N1: sorbitan monooleate was used as the surfactant, 1.8 g of T2: paraffin (C9 to C22) was used as the additive, and the pickling temperature was 60 ° C. went. The results are shown in Table 2.
  • Example 10 Example except that 1.2 g of N4: POE (2) alkyl (C12) ether was used as a surfactant, 1.8 g of T2: paraffin (C9 to C22) was used as an additive, and drying conditions were performed at 450 ° C. The same operation as 1 was performed. The results are shown in Table 2.
  • Example 11 The same operation as in Example 1 was performed except that 1.5 g of N6: POE (5) alkyl (sec-C11-15) ether was used as the surfactant and 1.5 g of T1: paraffin (C5) was used as the additive. It was. The results are shown in Table 2.
  • Example 12 The same operation as in Example 1 except that 1.2 g of N6: POE (5) alkyl (sec-C11-15) ether was used as the surfactant and T2: paraffin (C9-22): 1.8 g was used as the additive. Went. The results are shown in Table 2.
  • Example 13 The same operation as in Example 1 except that 1.5 g of N6: POE (5) alkyl (sec-C11-15) ether was used as the surfactant and 1.5 g of T3: paraffin (C16-22): 1.5 g was used as the additive. Went. The results are shown in Table 3.
  • Example 15 Raw material silicon-containing powder B: 15 g (solid content 99.9%) was charged in 72 g of ion-exchanged water, N1: sorbitan monooleate 1.5 g as a surfactant, T6: morpholine: 1.2 g, T5 as an additive. : Benzotriazole (BTA): The same operation as in Example 1 was performed except that 0.3 g was used, the pickling temperature was 60 ° C, and the drying temperature was 450 ° C. The results are shown in Table 3.
  • Example 17 A 0.5 L polypropylene reaction vessel was set in a water bath, charged with 20 g of 10% hydrofluoric acid, 28.8 g of 35% hydrochloric acid was added at room temperature with stirring, and subsequently A1: alkenyl succinic acid, N9 : 1.8 g of a mixed solution of alkenyl succinic acid half ester and N10: alkenyl succinic acid diester (mixing ratio 1: 1: 1) and T3: 1.2 g of paraffin (C16-22) were added to prepare a pickling solution. . To this, 48 g of silicon-containing powder D (solid content 62.5%) was gradually added within the range of the acid treatment set temperature or less while paying attention to the temperature rise and foaming situation.
  • the raw material slurry concentration in the acid treatment liquid is 30%, HF: 2%, hydrochloric acid: 10%, surfactant: 1.8%, additive: 1.2%.
  • the liquid temperature was raised to 70 ° C. in about 30 minutes, and the pickling treatment was performed by maintaining the temperature at this temperature for 3 hours. Subsequently, heating was stopped to cool to 30 ° C. or lower, and then stirring was stopped to allow the silicon-containing powder to settle. Next, the clear supernatant was removed by suction, and the same amount of ion-exchanged water as the removed supernatant was added to the settled slurry, stirred for 5 minutes, and allowed to settle again.
  • Example 18 The same operation as in Example 17 was performed, except that 1.8 g of A1: alkenyl succinic acid was used as the surfactant. The results are shown in Table 3.
  • Example 19 20% hydrofluoric acid 10 g, surfactant A1: alkenyl succinic acid, N9: alkenyl succinic acid half ester and N10: alkenyl succinic acid diester mixed solution (mixing ratio 1: 1: 1) 0.75 g, additive
  • surfactant A1 alkenyl succinic acid
  • N9 alkenyl succinic acid half ester
  • N10 alkenyl succinic acid diester mixed solution (mixing ratio 1: 1: 1) 0.75 g, additive
  • 0.5 g of paraffin (C16-22), 3 g of ion-exchanged water, and raw material silicon-containing powder D: 57 g (solid content 62.5%) were used. The results are shown in Table 3.
  • Example 20 Into a 0.5 L polypropylene reaction vessel, 63 g of ion-exchanged water was placed, set in a water bath and charged with raw material silicon-containing powder C1-1: 32 g (solid content 98.5%) at room temperature while stirring. Stirring was continued for a minute to prepare a slurry liquid in which the silicon-containing powder was uniformly dispersed. Under stirring, surfactant N1: sorbitan monooleate: 1.2 g and additive T2: 1.8 g of paraffin (C9-22) were added and dispersed by stirring for 5 minutes. Subsequently, 5.1 g of 98% sulfuric acid was gradually added in the range of room temperature to 70 ° C.
  • Example 21 200 g of ion-exchanged water was placed in a 1 L polypropylene reaction vessel, and the raw material silicon-containing waste liquid C2-1: 133 g (solid content 35.5%, aqueous coolant content: 53.8%, moisture content: 10.3) was stirred at room temperature. 8%), and stirring was continued for another 10 minutes to prepare a slurry liquid in which the silicon-containing powder was uniformly dispersed.
  • the slurry was subjected to suction filtration using a Nutsche made of polypropylene, and then a silicon-containing powder dehydrated cake from which the aqueous coolant was substantially removed (C2-2: solid content 53.2%, aqueous coolant content 2.8%, moisture 44. 5%).
  • C2-2 solid content 53.2%, aqueous coolant content 2.8%, moisture 44. 5%.
  • 37 g of ion-exchange water was placed in a 0.5 L polypropylene reaction vessel, set in a water bath, charged with 58 g of the above silicon-containing powder dehydrated cake (C2-2) at room temperature while stirring, and further for 30 minutes.
  • Example 22 The following prototype was made using the medium-scale prototype facility. After putting 21 kg of ion-exchanged water in a 230 L reactor, charge raw material silicon-containing powder sludge A (solid content 54.1%) 56 kg while stirring at room temperature, and stirring for 30 minutes makes the silicon-containing powder uniform. The dispersed slurry was adjusted. Next, 3.0 kg of a mixed solution (mixing ratio 1: 1) of surfactant N5: POE (3) alkyl (sec-C: 12 to 13) ether and additive T1: paraffin (C: 5) was added. And stirred for 5 minutes to disperse.
  • Example 23 Surfactant N1: sorbitan monooleate 1.5 kg, additive T6: morpholine: 1.2 kg, T5: benzotriazole (BTA): 0.3 kg, pickling temperature 60 ° C., drying temperature 450 ° C. The same operation as in Example 22 was carried out except that, and 25 kg of purified silicon-containing powder was obtained. The results are shown in Table 3.
  • Example 24 Ion-exchanged water: 34 kg, raw material silicon-containing powder B: 15 kg (solid content 99.9%), hydrofluoric acid was added, 35% hydrochloric acid 28.8 kg was added, and the external operation was the same as in Example 23 12.5 kg of purified silicon-containing powder was obtained. The results are shown in Table 3.
  • Comparative Example 1 Charge ion exchange water: 34 g into a 0.5 L polypropylene reaction vessel, set in a water bath and stir the raw material silicon-containing powder A: 56 g (solid content 54.1%) at room temperature, and continue for 30 minutes. Stirring was continued to obtain a slurry liquid in which the silicon-containing powder was uniformly dispersed.
  • 10 g of 20% hydrofluoric acid 10 g was gradually added within the range of the acid treatment set temperature or less while paying attention to the temperature rise and foaming situation, the scum-like sedimentary floating layer with the volume of the treatment solution was the same as the remarkable foaming The liquid level was increased by about twice as much as when charged.
  • the raw slurry concentration in the acid treatment liquid is 30%, and HF is 2%.
  • the liquid temperature was raised to 60 ° C., and the pickling treatment was performed by maintaining the temperature for 3 hours.
  • stirring was stopped and the silicon-containing powder was allowed to settle, but no change was observed in the scum layer, and the supernatant layer was also fine particles.
  • the results are shown in Table 4.
  • the raw material slurry concentration in the acid treatment solution at this time is 15%, HF: 7%, and sulfuric acid: 10%.
  • the liquid temperature was raised to 60 ° C., and the pickling treatment was performed by maintaining the temperature for 3 hours.
  • stirring was stopped and the silicon-containing powder was allowed to settle, but no change was observed in the scum layer, and the supernatant layer was also fine particles.
  • the results are shown in Table 4.
  • Comparative Example 3 In order to confirm the treatment method of Patent Document 2, 200 g of ion-exchanged water was put into a 1 L polypropylene reaction vessel, and the raw material silicon-containing waste liquid C2-1: 133 g (solid content 35.5%) was charged at room temperature while stirring. Further, stirring was continued for another 30 minutes to obtain a slurry liquid in which the silicon-containing powder was uniformly dispersed. Next, 47 g of a 0.5% aqueous solution of a polymeric cationic flocculant: PVAD6450 (with respect to solid content of about 5000 ppm) was added and stirred for 10 minutes at room temperature. Allowed to settle.
  • a polymeric cationic flocculant PVAD6450
  • this slurry solution was suction filtered using a polypropylene nutche and taken out as a dehydrated cake.
  • the dehydrated cake was dried using a dryer under a nitrogen atmosphere at 450 ° C. for 2 hours to recover a silicon-containing powder (C2-2).
  • Tables 1 and 4 show the impurity content of the recovered powder, and the results were high in metals, oxygen content, and carbon content.
  • Comparative Example 4 Into a 0.5 L polypropylene reaction vessel, 65 g of ion-exchanged water was placed, and set in a water bath, and while stirring, raw material silicon-containing powder B: 15 g (solid content 99.9%) was charged, and further for 30 minutes. Stirring was continued to obtain a slurry liquid in which the silicon-containing powder was uniformly dispersed.
  • 10 g of 20% hydrofluoric acid 10 g was gradually added within the range of the acid treatment set temperature or less while paying attention to the temperature rise and foaming situation, the scum-like sedimentary floating layer with the volume of the treatment liquid was the same as the remarkable foaming. The liquid level was increased by about twice as much as when charged.
  • this slurry solution was suction filtered using a polypropylene nutche and taken out as a dehydrated cake.
  • the dehydrated cake was dried by holding at 400 ° C. for 1 hour in a nitrogen atmosphere using a dryer to obtain a purified silicon-containing powder.
  • Table 4 shows the impurity content of this refined silicon-containing powder, which is a result of a large amount of metals, oxygen-containing prize, and carbon content.
  • Comparative Example 5 Into a 0.5 L polypropylene reaction vessel, 31 g of ion-exchanged water was placed, and set in a water bath and charged with raw material silicon-containing powder A: 56 g (solid content: 54.1%) at room temperature while stirring for another 30 minutes. Stirring was continued to obtain a slurry liquid in which the silicon-containing powder was uniformly dispersed. To this was added a surfactant (3.0 g of N7: POE (7) alkyl (sec-C: 11 to 15) ether) under stirring and dispersed by stirring for 5 minutes. Subsequently, 10% of 20% hydrofluoric acid: 10 g was gradually added within the range of the acid treatment set temperature or less while paying attention to the temperature rise and the foaming situation.
  • a surfactant 3.0 g of N7: POE (7) alkyl (sec-C: 11 to 15) ether
  • the raw material slurry concentration in the acid treatment liquid is 30%
  • the surfactant is 3.0%
  • the HF is 2%.
  • the liquid temperature was raised to 70 ° C. in about 30 minutes, and the pickling treatment was performed by maintaining the temperature at this temperature for 3 hours. Subsequently, after stopping heating and cooling to 30 ° C. or lower, stirring was stopped and the silicon-containing powder was allowed to settle and settle. However, no agglomeration effect was obtained, and fine particles floated in the supernatant layer. Since it was cloudy and sedimentation separation was impossible, the water washing in the next step was stopped. The results are shown in Table 4.
  • Comparative Example 6 The same operation as in Comparative Example 5 was carried out except that 1.2 g of N7: POE (7) alkyl (C11-15) ether was used as the surfactant and 1.8 g of T2: paraffin (C9 to C22) was used as the additive. It was. The results are shown in Table 4.
  • Comparative Example 7 The same operation as Comparative Example 5 was performed, except that 3.0 g of N8: POE (20) sorbitan laurate was used as the surfactant. The results are shown in Table 4.
  • Comparative Example 8 The same operation as in Comparative Example 5 was carried out except that 1.2 g of N8: POE (20) sorbitan laurate was used as the surfactant and 1.8 g of T2: paraffin (C9 to C22) was used as the additive. The results are shown in Table 4.
  • Comparative Example 9 The same operation as in Comparative Example 5 was performed except that 3.0 g of A2: ⁇ -naphthalenesulfonic acid formalin was used as the surfactant. The results are shown in Table 4.
  • Comparative Example 10 The same operation as Comparative Example 5 was performed except that 3.0 g of K1: POE (2) laurylamine was used as the surfactant. The results are shown in Table 4.
  • Comparative Example 11 The same operation as in Comparative Example 5 was performed, except that 1.2 g of K1: POE (2) laurylamine was used as the surfactant and 1.8 g of T2: paraffin (C9 to C22) was used as the additive. The results are shown in Table 4.
  • Comparative Example 13 The same operation as Comparative Example 5 was performed except that 1.5 g of K2: stearylamine acetate was used as the surfactant and 1.5 g of T5: benzotriazole was used as the additive. The results are shown in Table 4.
  • purified silicon-containing powder that can be efficiently reused as a high-purity silicon raw material can be recovered, which is industrially promising.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Silicon Compounds (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

L'invention concerne un procédé de récupération de poudre comprenant du silicium purifié permettant une récupération efficace, et dans lequel un oxyde de surface, des impuretés métalliques, ou similaire, sont éliminés d'une poudre de matière première comprenant du silicium qui comporte un oxyde de surface, des impuretés métalliques, ou similaire, évitant ainsi une réoxydation de la surface d'une poudre comprenant du silicium en cours de purification. Ce procédé de récupération de poudre comprenant du silicium purifié comporte : une étape de décapage fournissant une poudre (a) comprenant du silicium, au cours de laquelle une poudre de matière première comprenant du silicium et dont une partie ou l'ensemble de la surface est revêtue de dioxyde de silicium, est mise en contact avec un tensioactif non ionique dont la valeur HLB est au plus de 11 et / ou un tensioactif anionique dont la valeur HLB est au plus de 11, et avec une solution aqueuse pour décapage comprenant un acide fluorhydrique, et au cours de laquelle la surface de ladite poudre comprenant du silicium est nettoyée; une étape de lavage à l'eau fournissant une poudre (b) comprenant du silicium, au cours de laquelle la poudre (a) comprenant du silicium est nettoyée à l'eau; une étape de séparation solide-liquide fournissant une poudre (c) comprenant du silicium, au cours de laquelle la poudre (b) comprenant du silicium subit une séparation solide-liquide; et une étape de séchage au cours de laquelle la poudre (c) comprenant du silicium est séchée.
PCT/JP2010/073124 2009-12-22 2010-12-22 Procédé de récupération de poudre comprenant du silicium purifié WO2011078219A1 (fr)

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CN110342525A (zh) * 2019-07-09 2019-10-18 浙江师范大学 一种低成本去除冶金硅中杂质硼的方法
CN112456498A (zh) * 2020-11-12 2021-03-09 郑州中科新兴产业技术研究院 具有疏水包覆层的纳米硅材料、制备方法及应用
CN116177552A (zh) * 2023-02-22 2023-05-30 江苏秉盛环保工程有限公司 硅片切割液硅粉回收系统及其工艺

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JP5722601B2 (ja) * 2010-11-30 2015-05-20 サンワバイオテック株式会社 シリコン切削廃液の処理方法
JP5733042B2 (ja) 2011-06-14 2015-06-10 日本電気株式会社 フェムトセル無線基地局、通信制御方法およびプログラム
KR101264823B1 (ko) 2011-09-15 2013-05-15 (주)에스지이앤티 실리콘 파우더 리액션 시스템
CN105855213A (zh) * 2016-03-31 2016-08-17 苏州晶樱光电科技有限公司 硅晶片脱胶工艺
EP3434646A1 (fr) * 2017-07-25 2019-01-30 Total Solar International Procédé de recyclage de si-particles submicronique à partir d'un processus de production de tranche de si
BR112021017115A2 (pt) * 2019-03-27 2021-11-03 Wacker Chemie Ag Silício técnico e método para produção do mesmo

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CN108101068A (zh) * 2017-12-28 2018-06-01 无锡恒诚硅业有限公司 一种高结构度、高补强白炭黑的制备方法及由其得到的白炭黑
CN110342525A (zh) * 2019-07-09 2019-10-18 浙江师范大学 一种低成本去除冶金硅中杂质硼的方法
CN110342525B (zh) * 2019-07-09 2022-02-18 浙江师范大学 一种低成本去除冶金硅中杂质硼的方法
CN112456498A (zh) * 2020-11-12 2021-03-09 郑州中科新兴产业技术研究院 具有疏水包覆层的纳米硅材料、制备方法及应用
CN116177552A (zh) * 2023-02-22 2023-05-30 江苏秉盛环保工程有限公司 硅片切割液硅粉回收系统及其工艺
CN116177552B (zh) * 2023-02-22 2023-11-17 江苏秉盛环保工程有限公司 硅片切割液硅粉回收系统及其工艺

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