Classifications

• • 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
  • C01B33/20—Silicates
  • C01B33/32—Alkali metal silicates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y40/00—Manufacture or treatment of nanostructures
• • 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
  • C01B33/113—Silicon oxides; Hydrates thereof
  • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
  • C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
  • C01B33/141—Preparation of hydrosols or aqueous dispersions
• • 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
  • C01B33/113—Silicon oxides; Hydrates thereof
  • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
  • C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
  • C01B33/145—Preparation of hydroorganosols, organosols or dispersions in an organic medium
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C229/00—Compounds containing amino and carboxyl groups bound to the same carbon skeleton
  • C07C229/02—Compounds containing amino and carboxyl groups bound to the same carbon skeleton having amino and carboxyl groups bound to acyclic carbon atoms of the same carbon skeleton
  • C07C229/04—Compounds containing amino and carboxyl groups bound to the same carbon skeleton having amino and carboxyl groups bound to acyclic carbon atoms of the same carbon skeleton the carbon skeleton being acyclic and saturated
  • C07C229/06—Compounds containing amino and carboxyl groups bound to the same carbon skeleton having amino and carboxyl groups bound to acyclic carbon atoms of the same carbon skeleton the carbon skeleton being acyclic and saturated having only one amino and one carboxyl group bound to the carbon skeleton
  • C07C229/10—Compounds containing amino and carboxyl groups bound to the same carbon skeleton having amino and carboxyl groups bound to acyclic carbon atoms of the same carbon skeleton the carbon skeleton being acyclic and saturated having only one amino and one carboxyl group bound to the carbon skeleton the nitrogen atom of the amino group being further bound to acyclic carbon atoms or to carbon atoms of rings other than six-membered aromatic rings
  • C07C229/16—Compounds containing amino and carboxyl groups bound to the same carbon skeleton having amino and carboxyl groups bound to acyclic carbon atoms of the same carbon skeleton the carbon skeleton being acyclic and saturated having only one amino and one carboxyl group bound to the carbon skeleton the nitrogen atom of the amino group being further bound to acyclic carbon atoms or to carbon atoms of rings other than six-membered aromatic rings to carbon atoms of hydrocarbon radicals substituted by amino or carboxyl groups, e.g. ethylenediamine-tetra-acetic acid, iminodiacetic acids
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C59/00—Compounds having carboxyl groups bound to acyclic carbon atoms and containing any of the groups OH, O—metal, —CHO, keto, ether, groups, groups, or groups
  • C07C59/01—Saturated compounds having only one carboxyl group and containing hydroxy or O-metal groups
  • C07C59/10—Polyhydroxy carboxylic acids
  • C07C59/105—Polyhydroxy carboxylic acids having five or more carbon atoms, e.g. aldonic acids
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer

Definitions

• the present invention relates to a method for producing a silica sol having a low content of a polyvalent metal compound.
• Alkaline silicate aqueous solution (water glass) is used in a wide range of fields such as casting sand binders, binders, additives for pulp and paper, additives for soaps, raw materials for pharmaceuticals, and additives for civil engineering and building materials.
• various silica products such as colloidal silica dispersion (silica sol), silica gel, silica powder, lithium silicate aqueous solution, and potassium silicate aqueous solution are produced using an alkaline silicate aqueous solution as a starting material, and the silica sol is an alkaline silicate aqueous solution. It is produced by heating active silicic acid obtained by exchanging cations.
• compositions using these materials there are applications that require a composition having an extremely low content of metal oxides other than silica, for example, an abrasive for semiconductor wafers and semiconductor devices.
• Metal oxides other than silica as impurities in the alkaline silicate aqueous solution are derived from the raw materials for producing the alkaline silicate aqueous solution and are contained in the production process.
• Anhydrous sodium silicate (cullet) is obtained by washing silica sand or silica stone with water, drying it, mixing it with soda ash (sodium carbonate) or caustic soda, and cooling it after a melting reaction.
• Metal compounds other than silica derived from natural substances are present in silica sand, and metal compounds other than silica are also present in soda ash and caustic soda, and these metal compounds remain in cullet.
• the alkaline aqueous solution of silicate water glass is obtained by dissolving the cullet in a high-pressure melting pot or the like equipped with a boiler.
• the alkaline silicate aqueous solution produced by the conventional method was produced as an aqueous solution in which a relatively large amount of a metal compound other than silica was present.
• Active silicic acid purified using an alkaline aqueous solution of silicic acid as a method for producing the active silicic acid, for example, a silicic acid containing a chelating agent by mixing an aqueous alkali silicate solution with an iminodiacetic acid type chelating agent.
• a high-purity active silicic acid aqueous solution obtained by obtaining an alkaline aqueous solution, then bringing an alkaline alkali silicate solution containing a chelating agent into contact with an H-type cation exchanger, and bringing an active silicic acid aqueous solution containing a chelating agent into contact with an anion exchanger.
• Patent Document 1 a method for producing a silica sol produced by using the active silicic acid aqueous solution produced by the above method is disclosed (see Patent Document 2).
• the chelate forming ability may differ greatly depending on the form of the silicate ion.
• the sodium-containing silicate ion monomer forms a sodium-containing colloidal silicate ion micelle and polymerizes.
• the ability of polyvalent metal ions to form a complex with a chelating agent differs greatly depending on whether they coexist in the state of these silicate ion monomers or whether colloidal silicate ion micelles are formed and incorporated into the polymer. The inventors have found.
• polyvalent metal ions form a complex with a chelating agent before the silicate ions are polymerized, so that the chelate complex is contained in the silica matrix.
• a chelating agent before the silicate ions are polymerized, so that the chelate complex is contained in the silica matrix.
• the present invention describes a method for obtaining an aqueous sodium silicate solution by heating anhydrous sodium silicate (cullet), a chelating agent, and water, and a method for producing a high-purity silica sol using the aqueous sodium silicate solution (water glass). It is intended to be provided.
• a method for producing an aqueous sodium silicate solution which comprises a step of heating and mixing anhydrous sodium silicate, a chelating agent, and water at 100 to 270 ° C.
• the heating and mixing step is a step including a step of preparing a chelating agent-containing aqueous solution and a step of heating and mixing the anhydrous sodium silicate and the chelating agent-containing aqueous solution at 100 to 270 ° C.
• the method for producing an aqueous sodium silicate solution according to the first aspect As a third aspect, the sodium silicate according to the first or second aspect, wherein the addition ratio of the chelating agent is 0.1 to 3000 ppm with respect to the total mass of the SiO 2 component contained in the anhydrous sodium silicate.
• Method of producing aqueous solution As a fourth aspect, the method for producing an aqueous sodium silicate solution according to any one of the first to third aspects, wherein the heating time is 0.1 to 50 hours.
• the method for producing an aqueous sodium silicate solution according to any one of the first to fourth aspects which comprises heating and mixing under a pressure of 1 to 60 atm.
• a method of manufacturing a sodium silicate aqueous solution according to any one of the first aspect to the fifth aspect molar ratio of SiO 2 / Na 2 O of silicate in an aqueous solution of sodium is 1 to 10
• the chelating agent is an aminocarboxylic acid chelating agent, a phosphonic acid chelating agent, a gluconic acid chelating agent, or a metal salt thereof.
• the chelating agent is ethylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, diethylenetriaminepentacetic acid, nitrilotriacetic acid, gluconic acid, hydroxyethyliminotriacetic acid, L-aspartic acid-N, N-diacetic acid, hydroxyimino
• the method for producing an aqueous sodium silicate solution according to any one of the first to eighth aspects, which is disuccinic acid, aminotrimethylenephosphonic acid, hydroxyethanephosphonic acid, or a salt thereof.
• an active silicic acid aqueous solution including a step of bringing the sodium silicate aqueous solution obtained by the production method according to any one of the first to ninth aspects into contact with an H-type cation exchange resin.
• Production method As the eleventh viewpoint, the following steps (a) to (c): (A) Step: A step of contacting a sodium silicate aqueous solution obtained by the production method according to any one of the first to ninth aspects with a cation exchange resin to obtain an active silicic acid aqueous solution. Step (b): A step of heating the active silicic acid aqueous solution obtained in the step (a) to obtain a silica sol.
• the step (a) further includes an anion exchange before and / or after the sodium silicate aqueous solution is brought into contact with the cation exchange resin.
• the step (c) includes a step of performing cation exchange and / or anion exchange before and / or after ultrafiltration of the silica sol.
• the anhydrous sodium silicate is cullet, and the content of Cu contained in the silica sol obtained in the step (c) is 180 ppb or less and the content of Ni with respect to the total mass of the SiO 2 component.
• Sodium silicate aqueous solution including As a sixteenth aspect, sodium silicate containing a sodium-containing silicate ion monomer (A1) and a compound (B) containing at least one partial structure among the partial structures represented by the following (1) to (3).
• Aqueous solution (In the formula, M indicates a polyvalent metal ion, wavy line 1 indicates a covalent bond between a carbon atom or a phosphorus atom and an adjacent atom, and wavy line 2 indicates an ionic bond between the polyvalent metal ion M and an oxygen atom.
• a method for obtaining an aqueous sodium silicate solution by heating or heating and mixing anhydrous sodium silicate (cullet), a chelating agent, and water, and a method for producing a high-purity silica sol using the aqueous sodium silicate solution can be provided.
• a chelating agent is allowed to coexist with sodium silicate (cullet) at the stage of dissolving sodium silicate (cullet), that is, before the sodium silicate aqueous solution is formed, and the silicic acid anhydride is in that state.
• Sodium (cullet) is heated and dissolved in water, the obtained sodium silicate aqueous solution is brought into contact with a cation exchanger to obtain an active silicate aqueous solution, and a silica sol is produced through a heating step of the active silicate aqueous solution. Further, by performing ultrafiltration, a high-purity silica sol is formed.
• Anhydrous sodium silicate (cullet) is obtained by heating and melting silica sand or silica stone with soda ash (sodium carbonate) or caustic soda and cooling it.
• soda ash sodium carbonate
• caustic soda aqueous sodium silicate solution
• anhydrous sodium silicate (cullet) and water are heated and dissolved.
• silica sand and silica stone which are raw materials for the production of anhydrous sodium silicate (cullet), and metal compounds other than silica derived from soda ash and caustic soda remain in the cullet, the sodium silicate aqueous solution produced based on these remains in the cullet.
• anhydrous sodium silicate contains sodium ion, polyvalent metal ion and silicate ion, but silicate ion is easily polymerized by heating, and silicate ion monomer is silicate. Polymerization proceeds to acid ion dimers and colloidal silicate ion micelles.
• polyvalent metal ions are confined in the silica matrix (that is, polysiloxane), and a chelate compound between the polyvalent metal ions and the chelating agent cannot be formed, resulting in polyvalence.
• the metal ions are present in the active silicic acid and further in the silica particles, resulting in a silica sol rich in polyvalent metals.
• anhydrous sodium silicate (cullet) is dissolved in water, the chelating agent is present in the initial state, that is, in a state where the polymerization of silicate ions has not yet sufficiently proceeded, so that the chelating agent produces polyvalent metal ions.
• a chelate compound can be formed, sodium is removed from a silicic acid ion monomer containing sodium ions and polyvalent metal ions with an H-type cation exchange resin to produce active silicic acid in the silica matrix. Polyvalent metal ions are not taken in. Further, when an alkaline alkali silicate aqueous solution is applied to an H-type cation exchange resin, the chelate compound of the polyvalent metal ion in contact with the sulfonic acid group is a cation exchange of the polyvalent metal ion together with the sodium ion. In the production stage of, some polyvalent metal ions are removed to obtain high-purity active silicic acid.
• the silica sol when a silica sol is produced by heat polymerization using the high-purity active silicic acid, the polyvalent metal ion remaining in the silica sol exists as a chelate compound of the polyvalent metal ion, so that it is incorporated into the silica particles.
• the silica sol contains silica particles and a chelate compound of polyvalent metal ions, and this silica sol is high because the chelate compound of polyvalent metal ions is discharged from the silica sol by extrafiltration. A pure silica sol is obtained.
• the sodium-containing silicate ions are no longer polymerized into sodium-containing colloidal silicate ion micelles, and thus are polyvalent. Since the metal ions are incorporated into the silica matrix (polysiloxane), these polyvalent metal ions cannot form a chelate compound of the polyvalent metal ions even if a chelating agent is added. That is, polyvalent metal ions are present in the silica matrix, and polyvalent metal ions remain in both active silicic acid and silica particles produced from active silicic acid, resulting in cation exchange, anion exchange, and limitation.
• Polyvalent metal ions cannot be removed by external filtration. That is, when a chelating agent is added when the anhydrous sodium silicate (cullet) of the present invention is dissolved in water by heating, the sodium-containing silicate ion monomer and the partial structure represented by the above formulas (1) to (3) are formed. There is a chelating compound of polyvalent metal ion containing at least one of them.
• a chelating agent is present when anhydrous sodium silicate (cullet) is heated and dissolved in water, so that a chelate compound of polyvalent metal ions can be formed, and high-purity active silicic acid can be obtained by cation exchange treatment.
• a silica sol is produced by heating high-purity active silicic acid, the chelated product of polyvalent metal ions remaining by ultrafiltration of the produced silica sol is an ultrafiltration membrane system.
• the present invention is a method for producing an aqueous sodium silicate solution in which anhydrous sodium silicate (cullet), a chelating agent, and water are heated or mixed at 100 to 270 ° C, 100 to 180 ° C, or 110 to 180 ° C. ..
• a method for producing an aqueous sodium silicate solution is preferably a method of heating and mixing anhydrous sodium silicate and a chelating agent-containing aqueous solution obtained by mixing a chelating agent and water.
• Anhydrous sodium silicate (cullet) is obtained by heating and melting silica sand or silica stone (SiO 2 ) and soda ash (sodium carbonate) or caustic soda, and is obtained by cooling the mixture ratio of silica sand or silica stone and soda ash or caustic soda. Therefore, various cullet having a SiO 2 / Na 2 O molar ratio of about 2 to 10 is produced.
• the molar ratio is 2.1
• the molar ratio is 2.3
• the molar ratio is 3.1
• the molar ratio is 3.2
• the molar ratio is 3.7.
• An aqueous sodium solution (water glass) is obtained. These are used as JIS standard No. 1, No. 2, No. 3, No. 4, No. 5 sodium silicate aqueous solution (water glass).
• anhydrous sodium silicate (cullet) having the above molar ratio can be used as a raw material. These anhydrous sodium silicates (cullet) can be obtained from Tokuyama Corporation, Oriental Silica Corporation, PQ Corporation and the like.
• the chelating agent can be used in an addition ratio of 0.00005 to 0.15% by mass, 0.00005 to 0.015% by mass, or 0.00005 to 0.01% by mass with respect to anhydrous sodium silicate. , Typically 0.00001 to 0.001% by mass can be used. Expressed in ppm, the chelating agent can be used at an addition rate of 0.5 ppm to 1500 ppm, or 0.5 ppm to 150 ppm, or 0.5 ppm to 100 ppm with respect to anhydrous sodium silicate, typically. It can be used at an addition ratio of 0.1 ppm to 10 ppm.
• the chelating agent is 0.00001 to 0.3% by mass, or 0.00001 to 0.03% by mass, or 0.% by mass, based on the total mass of the silica (SiO 2 ) component of anhydrous sodium silicate (cullet). It can be used at an addition ratio of 0.001 to 0.02% by mass or 0.0001 to 0.02% by mass, and typically can be used at an addition ratio of 0.0001 to 0.002% by mass.
• the chelating agent is 0.1 ppm to 3000 ppm, or 0.1 ppm to 300 ppm, or 0.1 ppm to the total mass of the silica (SiO 2 ) component of sodium silicate (cullet) anhydrous. It can be used at an addition ratio of 200 ppm or 1 ppm to 200 ppm, and typically can be used at an addition ratio of 1 ppm to 20 ppm.
• Examples of the chelating agent used in the present invention include chelating agents containing a carboxyl group, a hydroxyl group, a phosphonic acid group, or a combination of these groups. These chelating agents are, for example, aminocarboxylic acid-based chelating agents, phosphonic acid-based chelating agents, gluconic acid-based chelating agents, or metal salts thereof (chelating metal salt-based chelating agents).
• the salt of the chelating agent having a carboxyl group can be an alkali metal salt, and examples thereof include sodium salt, potassium salt and lithium salt, preferably sodium salt.
• an aminocarboxylic acid-based chelating agent which is a nitrogen-containing chelating agent.
• the aminocarboxylic acid-based chelating agent has an amino group and a carboxyl group in the structure, and may further have a hydroxyl group. Further, the carboxyl group can form the above-mentioned salt, for example, a sodium salt may be formed.
• a secondary amino group or a tertiary amino group can be used as the amino group contained in the aminocarboxylic acid-based chelating agent.
• a secondary amino group and a tertiary amino group may be contained alone or in combination in one molecule of the chelating agent.
• a chelating agent having a tertiary amino group is preferably used.
• the chelating agent can have one or more amino groups in one molecule, and can have, for example, 1 to 6, 1 to 4, or 2 to 4 amino groups.
• the structure in which the chelating agent forms a chelate complex with a metal ion is a group containing a carboxyl group, a hydroxyl group, a phosphonic acid group, or a combination thereof as a functional group for chelate formation.
• a nitrogen atom in the chelating agent molecule can be involved as a functional group for chelation formation, and when a hydroxyl group or a phosphonic acid group is contained, those groups can be involved as a functional group for chelation formation.
• a chelating agent forms a complex with a metal ion
• the chelating agent has a plurality of carboxyl groups
• one chelating agent molecule and one polyvalent metal ion molecule form a chelating complex, but a chelate having a single carboxyl group.
• a hydroxyl group or a phosphonic acid group can form a chelate
• one molecule of a polyvalent metal ion can form a chelate structure by a plurality of chelating agents.
• R 1 to R 5 in the above formulas (4-1) to (4-10) represent hydrogen atoms, alkali metals, or NH 4 , respectively, and examples of the alkali metals include sodium and lithium.
• R 1 to R 5 may be the same or different. In particular, hydrogen atoms and sodium are preferably used for R 1 to R 5 , respectively.
• Formula (4-1) represents ethylenediaminetetraacetic acid or a salt thereof
• formula (4-2) represents hydroxyethylethylenediaminetriacetic acid or a salt thereof
• formula (4-3) represents diethylenetriaminepentacetic acid or a salt thereof.
• Formula (4-4) represents nitrilotriacetic acid or a salt thereof
• formula (4-5) represents gluconic acid or a salt thereof
• formula (4-6) represents hydroxyethyliminotriacetic acid or a salt thereof.
• (4-7) represents L-aspartic acid-N, N-diacetic acid or a salt thereof
• formula (4-8) represents hydroxyiminodisuccinic acid or a salt thereof
• formula (4-9) is aminotri.
• Methylenephosphonic acid or a salt thereof is shown
• the formula (4-10) shows hydroxyethanephosphonic acid or a salt thereof.
• one type of chelating agent can be used, or two or more types of chelating agents can be used in combination.
• ethylenediaminetetraacetic acid represented by the formula (4-1) or a salt thereof is a typical chelating agent, and ethylenediaminetetraacetic acid tetrasodium can be preferably used.
• the method for producing an aqueous sodium silicate solution of the present invention is a production method including a step of heating or mixing anhydrous sodium silicate, a chelating agent, and water at 100 to 270 ° C., but is typically silicon dioxide. It is a production method including a step of heating or heating and mixing sodium silicate and an aqueous solution containing a chelating agent at 100 to 180 ° C.
• a chelating agent-containing aqueous solution is used, the chelating agent is dissolved in water, and a chelating agent aqueous solution having a chelating agent concentration of, for example, 0.001 to 10% by mass or 0.01 to 5% by mass is prepared and used. Can do things.
• the heating temperature is 100 to 270 ° C, 100 to 180 ° C, or 110 to 180 ° C
• steam containing a chelating agent can be used.
• heating or mixing is performed under a pressure of 1 atm to 60 atm, 1 atm to 10 atm, or 1.5 atm to 10 atm, and the heating time is 0.1 to 50. It can be time.
• the heating time can be 50 hours or more, but economically it can be up to 50 hours.
• sodium silicate aqueous solution one having a molar ratio of SiO 2 / Na 2 O in the sodium silicate aqueous solution in the range of 1 to 10, 1 to 4, or 2 to 4 can be obtained. This molar ratio depends on the molar ratio of the components contained in anhydrous sodium silicate (cullet).
• the concentration of the sodium silicate aqueous solution is determined by the mixing ratio of anhydrous sodium silicate (cullet) and water (aqueous solution containing a chelating agent), and it is possible to manufacture and concentrate at a low concentration or to increase the concentration of anhydrous sodium silicate. It can dissolve sodium silicate (cullet).
• an aqueous sodium silicate solution is commercially available in an amount of 30% by mass to 50% by mass, but when a product is manufactured using this sodium silicate as a raw material, the aqueous sodium silicate solution is added in an amount of 1% by mass to water. It can also be used by diluting it to 10% by mass.
• the chelating agent since the chelating agent is exposed to a highly alkaline aqueous solution having a pH of 9 to 14 or 10 to 13, a part of the structure of the chelating agent may be decomposed, but later when an active silicate aqueous solution is produced. Since it is possible to remove the polyvalent metal ion M together with the sodium ion of sodium silicate with the H-type cationic resin, at least the partial structures represented by the formulas (1) to (3) are contained in the aqueous sodium silicate solution. It is considered that there is a chelate complex having a partial structure of any one of the above, or a partial structure in which two or more of them are combined.
• the silicate ion monomer and the polyvalent metal ion M before the polymerization of silicate ions proceed.
• Chelate compound will be present. That is, it contains a sodium-containing silicate ion monomer (A1) and a compound (B) in which a chelating agent having a carboxyl group, a hydroxyl group, a phosphonic acid group, or a combination of these groups and a polyvalent metal ion M are bonded.
• A1 sodium-containing silicate ion monomer
• B a compound having a carboxyl group, a hydroxyl group, a phosphonic acid group, or a combination of these groups and a polyvalent metal ion M are bonded.
• anhydrous sodium silicate (cullet) dissolves in water (hot water)
• the sodium-containing silicate ion is a monomer, but after a lapse of time due to heating, the sodium-containing silicate ion monomer is in the form of a sodium-containing colloid. Transforms into silicate ion micelles.
• a solution of anhydrous sodium silicate (cullet) in water has a sodium-containing silicate ion monomer (A1) and a carboxyl group, a hydroxyl group, a phosphonic acid group, or a combination thereof. It can be said that it is an alkaline silicate aqueous solution containing a compound (B) in which a chelating agent and a polyvalent metal ion M are bonded, and further containing a sodium-containing colloidal silicate ion micelle (A2). More specifically, it contains a sodium-containing silicate ion monomer (A1) and a compound (B) containing at least one partial structure among the partial structures represented by the following formulas (1) to (3).
• the polyvalent metal ion M forms a chelate complex with a chelating agent, so that it is not incorporated into the silica network constituting the polysilicate ion such as colloidal silicate ion micelle, and thus is a cation. It can be removed by replacement, and can also be removed by subsequent ultrafiltration.
• the polyvalent metal ion M is a polyvalent metal ion M other than the alkali metal ion contained in the raw material anhydrous sodium silicate (cullet).
• the polyvalent metal ion M include calcium ion, magnesium ion, aluminum ion, barium ion, copper ion, nickel ion, cobalt ion, iron ion, titanium ion, chromium ion, manganese ion, zinc ion, zirconium ion, tin ion and the like. Is contained in the cullet.
• the present invention is made for the purpose of obtaining a sodium silicate aqueous solution and a silica sol in which polyvalent metal ions M are reduced, particularly copper ions and nickel ions are reduced.
• the aqueous sodium silicate solution obtained by heating anhydrous sodium silicate (cullet) in water contains 300 ppb or more of copper ions and 120 ppb or more of nickel ions with respect to silica in sodium silicate.
• the silica sol can be produced through the steps (a) to (c).
• the cation exchange resin used in the step (a) is a cation exchange resin having a functional group capable of exchanging hydrogen ions with other cations.
• a sulfonic acid type H-type strongly acidic cation exchange resin or a carboxylic acid type H-type weakly acidic cation exchange resin can be used.
• the sulfonic acid type strongly acidic cation exchange resin should be adjusted to H type. Is preferable.
• these sulfonic acid type strongly acidic cation exchange resins for example, Amberlite IR-120B manufactured by Organo Corporation and trade name can be used.
• the step (a) is a step of removing alkali metal ions (particularly sodium) from the alkaline silicate aqueous solution by cation exchange to obtain an active silicate aqueous solution.
• alkali metal ions particularly sodium
• some polyvalent metal ions can be removed by cation exchange even from a chelating agent containing polyvalent metal ions.
• the aqueous sodium silicate solution having a concentration of 1 to 10% by mass or 1 to 6% by mass as the concentration of the SiO 2 component can be brought into contact with the cation exchange resin.
• the contact can be performed by a batch type or a column type, and industrially, a method of filling an ion exchange tower with a cation exchange resin and passing an aqueous sodium silicate solution through it can be used.
• the liquid passing speed is 1 to 30 in space speed (1 / hr), and the temperature can be 10 to 80 ° C.
• the Cu content in the obtained active silicic acid aqueous solution is 230 ppb or less, for example 180 ppb or less, typically 50 ppb to 180 ppb, and the Ni content is set with respect to the mass of the SiO 2 component. It can be 140 ppb or less, for example 100 ppb or less, typically 50 ppb to 100 ppb with respect to the mass of the SiO 2 component.
• the concentration of the SiO 2 component of the active silicic acid aqueous solution obtained in the step (a) is, for example, about 1 to 10% by mass or about 1 to 6% by mass.
• anion exchange can be arbitrarily performed before or after cation exchange.
• the sodium silicate aqueous solution can be brought into contact with the anion exchange resin before or after the cation exchange resin is brought into contact with the resin.
• the anion exchange resin a strong basic anion exchange resin or a weakly basic anion exchange resin can be used.
• the step (b) is a step of heating and aging the active silicic acid aqueous solution obtained in the step (a) to produce a silica sol.
• the heating temperature is about 50 to 180 ° C. Pressurized granulation is possible even at a temperature exceeding 100 ° C., and a closed type pressurizer or an open type pressurizer can be used.
• Silica sol can be produced by sizing silica by heating at the above temperature under stirring. A multi-step build-up process can be used for sizing.
• the silica particles can be sized by charging the heel liquid with the active silicic acid aqueous solution.
• the sizing time for forming silica particles is about 1 to 100 hours, and the sizing time can be adjusted to obtain a desired silica particle size.
• the step (c) is a step of ultrafiltration of the silica sol obtained in the step (b).
• Examples of the step of performing ultrafiltration include a step of passing through an ultrafiltration device. By passing through an ultrafiltration device, the SiO 2 concentration of the silica sol can be increased and concentrated.
• free metal ions in the silica sol, a chelating agent, and a metal compound-containing chelating agent (chelating compound of polyvalent metal ions) derived from the above-mentioned alkaline aqueous solution of silicate can be removed from the silica sol together with concentration.
• the polyvalent metal ions remaining in the active silicic acid aqueous solution without being removed in the step (a) are captured by the chelating agent and chelated. Since it forms a complex, it is not incorporated into the polysiloxane skeleton in the process of forming polysilicic acid (polysiloxane structure) by silicic acid monomers and oligomers in active silicic acid to form silica particles, and it is contained in the silica sol. It exists in a free state.
• the chelate compound of polyvalent metal ions is discharged to the outside of the system by the ultrafiltration in the step (c), and a silica sol in which the metal ions in the silica sol are reduced can be produced.
• cation exchange and / or anion exchange can be performed before and after ultrafiltration.
• the silica sol obtained through the step (c) of the present invention has a Cu content of 180 ppb or less with respect to the total mass of the SiO 2 component, typically 50 ppb to 180 ppb, and a Ni content of the entire SiO 2 component. It is 100 ppb or less with respect to the mass, typically 50 ppb to 100 ppb.
• an organic film such as a cellulose acetate membrane, an aromatic polyamide membrane, a polyvinyl alcohol membrane, or a polysulfone membrane, or a ceramic membrane is used, and silica sol is continuously flowed in a certain direction along the surface of the membrane.
• Water in which impurities (in this case, a compound in which a chelating agent and polyvalent metal ion are bonded) is concentrated is continuously discharged to purify the silica sol and increase the silica concentration of the silica sol for concentration.
• a film having a pore size of about 0.1 ⁇ m to 0.001 ⁇ m or about 0.01 ⁇ m to 0.001 ⁇ m and a molecular weight cut-off of about 30,000 to 3 million can be used.
• Ultrafiltration can be carried out within the range possible depending on the heat resistance and pressure resistance of the membrane. For example, in the case of an organic membrane, filtration can be performed at a temperature of 10 to 80 ° C. and a pressure of 0.3 MPa or less. In the case of a ceramic film, filtration can be performed at a temperature of 300 ° C. or lower and a pressure of 10 MPa or less.
• the particle size of the silica particles in the silica sol obtained in the step (c) is represented by the average primary particle size (nm), and is calculated from the specific surface area measured by the nitrogen gas adsorption method (BET method).
• BET method nitrogen gas adsorption method
• a silica sol in which silica particles having an average primary particle diameter of 1 to 500 nm, 1 to 200 nm, or 5 to 100 nm are dispersed in an aqueous medium can be obtained.
• the silica concentration of the silica sol can be arbitrarily adjusted in the range of 1 to 40% by mass, 5 to 40% by mass, 10 to 30% by mass, and 20 to 30% by mass of SiO 2 .
• ion exchange can be arbitrarily carried out before or after the ultrafiltration, before or after the ultrafiltration.
• ion exchange cation exchange, anion exchange, and a combination of cation exchange and anion exchange can be carried out.
• the active silicic acid aqueous solution obtained in the step (a) and the silica sol obtained in the step (c) can be filtered with a filter to remove coarse particles.
• membrane type filters pleated type filters, depth type filters, pincushion type filters, surface type filters, roll type filters, depth pleated type filters, diatomaceous earth containing type filters, etc.
• membrane type filters can be used, and among them, membrane type filters.
• the absolute pore diameter of the filter can be set to 0.3 ⁇ m to 3.0 ⁇ m.
• a pH adjuster can be added to the obtained silica sol to arbitrarily set the pH to 0.5 to 13, and alkaline silica sol and acidic silica sol can be obtained.
• Known acids and alkalis can be used as the pH adjuster.
• the acid include inorganic acids such as sulfuric acid, hydrochloric acid and nitrate, organic acids such as formic acid, acetic acid, oxalic acid, citric acid and paratoluenesulfonic acid, and examples of alkalis include inorganic alkalis such as NaOH, KOH and ammonia, ethylamine, etc.
• Examples include amines such as diethylamine, triethylamine, monoethanolamine, diethanolamine and triethanolamine, and quaternary ammonium hydroxide such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide. Be done. These can be used alone or as a mixture.
• the shape of the silica particles in the silica sol can be changed by the sizing step of the silica particles in the step (b), and was measured by (dynamic light scattering method average particle diameter nm) / (nitrogen gas adsorption method).
• Silica particles having an average primary particle diameter (nm) of, for example, 1.1 to 40, 1.1 to 20, or 1.1 to 10, 1.1 to 5, or 1.1 to 4 can be obtained.
• the dispersion medium of the above silica sol can be changed from an aqueous medium to an organic solvent.
• the solvent can be changed by an evaporation method using an evaporator or an ultrafiltration method using an ultrafiltration membrane.
• the organic solvent include methanol, ethanol, n-propanol, iso-propanol, butanol, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl isobutyl carbinol, and propylene glycol mono.
• the surface of the silica sol can be surface-coated with at least one silane compound (silane coupling agent) selected from the group consisting of silane compounds represented by the following formulas (5) and (6).
• silane compound silane coupling agent
• R 11 represents an organic group having an acryloxy group, a methacryloxy group, an aryl group, an alkyl group, an epoxy group, a mercapto group, an amino group, or a cyano group, or a combination thereof, and the functional group is It may contain a nitrogen atom, an oxygen atom, and a sulfur atom.
• the functional group is a Si atom bonded to a Si—C bond
• R 12 is a hydrate consisting of an alkoxy group, an acyloxy group, or a halogen group. It indicates a decomposing group, and a represents an integer of 0 to 3 or 1 to 3.
• a represents an integer of 0 to 3 or 1 to 3.
• R 13 represents an alkyl group and is bonded to a silicon atom by a Si—C bond
• R 14 represents an alkoxy group, an acyloxy group, or a halogen group
• Y represents an alkylene group.
• silane compound represented by the formula (6) coats the surface of the silica particles, at least one group showing R 14 forms a Si—O—Si bond on the surface of the silica particles.
• alkyl group examples include an alkyl group having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a cyclopropyl group, an n-butyl group, an i-butyl group, and the like.
• s-Butyl group t-butyl group, cyclobutyl group, 1-methyl-cyclopropyl group, 2-methyl-cyclopropyl group, n-pentyl group, 1-methyl-n-butyl group, 2-methyl-n-butyl Groups, 3-methyl-n-butyl group, 1,1-dimethyl-n-propyl group, 1,2-dimethyl-n-propyl group and the like can be mentioned.
• an alkylene group an alkylene group derived from the above-mentioned alkyl group can be mentioned.
• Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group and the like
• the arylene group is a group derived from the above aryl group, and examples thereof include a phenylene group, a naphthylene group and an anthrylene group.
• Examples of the alkoxy group include an alkoxy group having 1 to 10 carbon atoms, for example, a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, an s-butoxy group, and the like.
• Examples thereof include a t-butoxy group, an n-pentyloxy group, a 1-methyl-n-butoxy group, a 2-methyl-n-butoxy group and the like.
• Examples of the acyloxy group include an acyloxy group having 2 to 10 carbon atoms, such as a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an i-propylcarbonyloxy group, and an n-butylcarbonyloxy group.
• Examples of the halogen group include fluorine, chlorine, bromine and iodine.
• silane compound (silane coupling agent) represented by the above formula (5) examples include tetramethoxysilane, tetrachlorosilane, tetraacetoxysilane, tetraethoxysilane, tetran-propoxysilane, tetraisopropoxysilane, and tetran-.
• silane compound (silane coupling agent) represented by the formula (6) examples include methylenebistrimethoxysilane, methylenebistrichlorosilane, methylenebistriacetoxysilane, ethylenebistriethoxysilane, ethylenebistrichlorosilane, ethylenebistriacetoxysilane, and propylenebistriethoxysilane.
• silane compound silane coupling agent represented by the formula (6).
• Formula (6-1) is hexamethyldisilazane
• formula (6-2) is hexamethyldisilane
• formula (6-3) is hexamethyldisiloxane.
• These silane compounds (silane coupling agents) can be obtained from Tokyo Chemical Industry Co., Ltd.
• the silica sol obtained in the present invention can be used for general purposes such as casting sand binders, binders, additives for pulp and paper, additives for soaps, raw materials for pharmaceuticals, and additives for civil engineering and building materials. Taking advantage of its high purity, it is used as an abrasive for silicon wafers, an abrasive for semiconductor devices (CMP), catalysts, carriers for catalysts, high-purity ceramic raw materials, columns for pharmaceutical purification, plastic lenses and glass surface coatings. It is useful for agent components and the like.
• Anhydrous sodium silicate (cullet) A cullet manufactured by Oriental Silica Corporation was prepared. The SiO 2 / Na 2 O molar ratio was 3.2. Ethylenediaminetetraacetic acid tetrasodium: Made by Kirest Co., Ltd., trade name Kirest OD was prepared. Hydroxyethanephosphonic acid: Made by Kirest Co., Ltd., trade name Kirest PH-210 was prepared. Sodium gluconate: Made by Kirest Co., Ltd., trade name Kirest GB was prepared. H-type strongly acidic cation exchange resin: A commercially available cation exchange resin was prepared as H-type with an aqueous sulfuric acid solution.
• Measurement of average primary particle size The average primary particle size (nm) was measured by the nitrogen gas adsorption method (BET method).
• Measurement of pH Measurement was performed using a pH measuring device manufactured by DKK-TOA CORPORATION.
• Measurement of electrical conductivity Measurement was performed using an electrical conductivity measuring device manufactured by DKK-TOA CORPORATION.
• Measurement of multivalent metal component and its content Qualitative and quantified by ICP emission spectrometer manufactured by PerkinElmer Inc.
• Example 1 To a stainless steel autoclave container having a capacity of 3 liters, 159 g of anhydrous sodium silicate cullet, 1041 g of pure water and 0.02 g of a 1 mass% tetrasodium ethylenediamine tetraacetate aqueous solution were added and heated at 150 ° C. for 1 hour to obtain a silica concentration of 10 mass%. An aqueous sodium silicate solution was prepared. The sodium silicate aqueous solution had Cu and Ni contents per silica contained in the aqueous solution of 364 ppb and 152 ppb, respectively.
• Pure water is added to this aqueous sodium silicate solution to dilute it to a silica concentration of 4% by mass, and the solution is passed through a column packed with an H-type strong acid cation exchange resin (trade name: Amberlite IR-120B) to have a silica concentration.
• H-type strong acid cation exchange resin trade name: Amberlite IR-120B
• a 3.4 mass% active silicic acid aqueous solution was obtained.
• 29 g of the sodium silicate aqueous solution having a silica concentration of 10% by mass and 265 g of pure water were placed in a glass container having an internal volume of 3 liters, and heated to 80 ° C. in an oil bath under stirring.
• This reaction solution is a silica sol having a silica concentration of 3.2% by mass, a pH of 10.0, an electric conductivity of 427 ⁇ S / cm, and an average primary particle size (particle size equivalent to the specific surface area of the BET method) of silica particles by the nitrogen gas adsorption method of 13 nm. It was. Subsequently, 2427 g of this reaction solution was heated to 70 ° C. and concentrated using a commercially available ultrafiltration membrane (molecular weight cut off of 200,000) until the silica concentration reached about 30% by mass to obtain 236 g of silica sol.
• a commercially available ultrafiltration membrane molecular weight cut off of 200,000
• This silica sol had a silica concentration of 30.5% by mass, a pH of 9.2, a conductivity of 2020 ⁇ S / cm, a Cu content of 108 ppb with respect to silica, and a Ni content of 92 ppb with respect to silica.
• the same operations as in Example 1 were carried out, and Examples 2 to 9, Comparative Examples 1 to 3 and Reference Example 1 were performed. The operation and results are shown in the table below.
• Table 1 shows the operation when anhydrous sodium silicate (cullet) is dissolved in water by heating.
• item X1 indicates the mass (g) of anhydrous sodium silicate (cullet) charged in the stainless steel autoclave device
• item X2 indicates the mass (g) of pure water charged in the stainless steel autoclave device
• X3 is the mass (g) of the chelating agent-containing aqueous solution charged in the stainless steel autoclave apparatus
• Examples 1 to 7 and Comparative Example 3 show the mass (g) of the ethylenediamine tetraacetate tetrasodium aqueous solution having a concentration of 1% by mass.
• Example 8 shows the mass (g) of the 1 mass% concentration hydroxyethanephosphonic acid aqueous solution
• Example 9 shows the mass (g) of the 1 mass% sodium gluconate aqueous solution
• Reference Example 1 shows 0.02.
• the mass (g) of the aqueous solution of tetrasodium ethylenediamine tetraacetate having a mass% concentration is shown.
• Item X4 shows the amount (ppm) of the chelating agent added to anhydrous sodium silicate (cullet) when dissolving anhydrous sodium silicate (cullet)
• item X5 indicates the amount of anhydrous sodium silicate (cullet) when dissolving anhydrous sodium silicate (cullet).
• the amount (ppm) of the chelating agent added to the silica in the cullet) is shown, item X6 shows the silica concentration (%) in the anhydrous sodium silicate (cullet) in the stainless autoclave device, and the item X7 shows the anhydrous sodium silicate.
• the heating dissolution temperature (° C.) of (Cullet) in water is shown, and item X8 shows the heating dissolution time (hours) of anhydrous sodium silicate (Cullet) in water.
• Table 2 shows the operations and physical properties of items X9 to X13 after the sodium silicate aqueous solution (water glass) was prepared.
• item X9 is a 1% by mass concentration of sodium silicate aqueous solution (water glass) added to the sodium silicate aqueous solution (water glass) after heat-dissolving anhydrous sodium silicate (cullet) in water to prepare an aqueous sodium silicate aqueous solution (water glass).
• item X10 is an aqueous sodium silicate (water) after heat-dissolving anhydrous sodium silicate (cullet) in water to prepare an aqueous sodium silicate (water glass).
• item X11 indicates the sodium silicate aqueous solution (water glass) after dissolving anhydrous sodium silicate (cullet) in water to prepare a sodium silicate aqueous solution (water glass).
• item X12 indicates the copper content (ppb) with respect to the silica in the obtained sodium silicate aqueous solution (water glass)
• item X13 was obtained. The content of nickel (ppb) with respect to silica in the sodium silicate aqueous solution (water glass) is shown.
• Example 7 anhydrous sodium silicate (cullet) was heated and dissolved in water to prepare an aqueous sodium silicate solution (water glass). Further, in Comparative Example 3, since anhydrous sodium silicate (cullet) could not be dissolved in water by heating, no further tests were conducted.
• Table 3 shows the operation during the production of the active silicic acid aqueous solution and the physical characteristics of the obtained active silicic acid aqueous solution.
• item Y1 indicates the mass (g) of the aqueous sodium silicate solution (water glass)
• item Y2 indicates the mass (g) of pure water added for dilution
• item Y3 indicates the obtained active silica.
• the mass (g) of the acid aqueous solution is shown
• item Y4 shows the copper content (ppb) with respect to silica (SiO 2 ) in the obtained active silicic acid aqueous solution
• item Y5 is shown in the obtained active silicic acid aqueous solution.
• the content (ppb) of nickel with respect to silica (SiO 2 ) is shown.
• Table 4 shows the physical characteristics of the reaction solution (silica sol before ultrafiltration).
• item Z1 shows the silica concentration (mass%) of the silica sol
• item Z2 shows the pH of the silica sol
• item Z3 shows the electric conductivity ( ⁇ S / cm) of the silica sol
• item Z4 shows the nitrogen gas adsorption method.
• the average primary particle diameter (nm) by (BET method) is shown.
• Table 5 shows the physical characteristics of the silica sol after ultrafiltration.
• item Z5 shows the mass (g) of the silica sol charged in the ultrafiltration device
• item Z6 shows the mass (g) of the silica sol obtained through the ultrafiltration device
• item Z7 is the ultrafiltration device.
• the silica concentration (%) of the silica sol obtained through the filtration device is shown
• item Z8 shows the pH of the silica sol obtained through the ultrafiltration device
• item Z9 passes through the ultrafiltration device.
• the electrical conductivity ( ⁇ S / cm) of the obtained silica sol is shown
• item Z10 shows the copper content (ppb) of the silica sol obtained through the ultrafiltration device with respect to silica
• item Z11 is ultrafiltration.
• the content of nickel (ppb) with respect to silica of the silica sol obtained through the apparatus is shown.
• a chelating agent is present when anhydrous sodium silicate (cullet) is dissolved in water by heating, and the step (a) is carried out regardless of the type of the chelating agent. It was found that the polyvalent metal was reduced in the step of the active silicic acid aqueous solution and the step of forming the silica sol in the step (c).
• Comparative Example 2 a chelating agent was added after the active silicic acid aqueous solution was formed, and the obtained silica sol did not have a sufficiently reduced polyvalent metal. Further, in Comparative Example 3, the temperature at which anhydrous sodium silicate (cullet) was heated and dissolved in water was 60 ° C., and anhydrous sodium silicate (cullet) could not be sufficiently dissolved.
• the purity silica sol can be used for general purposes such as casting sand binders, binders, additives for paper and pulp, additives for soaps, raw materials for pharmaceuticals, and additives for civil engineering and building materials. Taking advantage of its particularly high purity, it is used as an abrasive for silicon wafers, an abrasive for semiconductor devices (CMP), catalysts, carriers for catalysts, high-purity ceramic raw materials, columns for pharmaceutical purification, plastic lenses and glass surface coatings. It is useful for agent components and the like.

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