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WO1992009543A1 - Procede de preparation de particules creuses en ceramique - Google Patents

Procede de preparation de particules creuses en ceramique Download PDF

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Publication number
WO1992009543A1
WO1992009543A1 PCT/US1991/008979 US9108979W WO9209543A1 WO 1992009543 A1 WO1992009543 A1 WO 1992009543A1 US 9108979 W US9108979 W US 9108979W WO 9209543 A1 WO9209543 A1 WO 9209543A1
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WO
WIPO (PCT)
Prior art keywords
metal oxide
solution
particles
silicon
forming
Prior art date
Application number
PCT/US1991/008979
Other languages
English (en)
Inventor
Sivananda S. Jada
Original Assignee
Manville Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Manville Corporation filed Critical Manville Corporation
Publication of WO1992009543A1 publication Critical patent/WO1992009543A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/009—Porous or hollow ceramic granular materials, e.g. microballoons
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
    • C01B13/14—Methods for preparing oxides or hydroxides in general
    • C01B13/34—Methods for preparing oxides or hydroxides in general by oxidation or hydrolysis of sprayed or atomised solutions
    • 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
    • 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
    • C01B33/26—Aluminium-containing silicates, i.e. silico-aluminates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/30—Particle morphology extending in three dimensions
    • C01P2004/32—Spheres
    • C01P2004/34—Spheres hollow
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/32—Thermal properties

Definitions

  • the present invention is concerned with the manufacture of particles in the ceramic field utilizing sol-gel technology.
  • U.S. Patent No. 3,709,706 describes refractory aggregates and shaped articles such as fibers, films, flakes and microspheres of zirconia and silica mixtures. Fibers were spun from an aqueous colloidal dispersion of silica and aqueous solution of zirconium diacetate.
  • U.S. Patent No. 4,349,456 describes shaped and fired porous or impermeable non-vitreous ceramic microcapsules of metal oxide made by a non-melt process comprising the liquid extraction of aqueous metal oxide precursor with a dehydrating liquid having a limited water solubility and drying and firing the resulting gelled microcapsules.
  • U.S. Patent No. 4,931,414 describes solid transparent non-vitreous microspheres (zirconia-silica) are formed by a extractive gelation (extracting carboxylic acid away from zirconyl carboxylate) of a sol in liquid medium such as hot peanut oil.
  • the invention is concerned with the process of preparing ceramic hollow discrete particles comprising the steps:
  • FIGURE 1 is a schematic diagram of the overall process of the present invention to produce the spherical particles;
  • FIGURE 2 shows zircon hollow spheres at 1000 magnification;
  • FIGURE 3 is an X-ray diffraction pattern of zircon hollow particles calcined at 1100°C.
  • the present invention is concerned with obtaining hollow discrete particles of ceramic materials.
  • One of the initial steps is to prepare a silicon containing aqueous material.
  • the silicon that may be employed can generally be characterized as silicon oxides or alkoxides.
  • the silicon oxides can be silicon dioxide or polymers thereof.
  • the silicon alkoxides can be those comprised of the silicon containing materials further comprising hydrocarbyl containing lower alkyl radicals from 1 to 6 carbon atoms, preferably ethyl.
  • Illustrative materials are tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane and amyltriethoxysilane, and the like.
  • the silicon material be colloidal silica which has an acidic ph, preferably a ph of 3-5.
  • the colloidal silica is preferably in an aqueous state with a particle size less than 50 nanometers, preferably 0.5-25 nanometers.
  • the ph is adjusted from the normal ph of colloidal silica which is basic, usually about 8 to 10 by the use of acidic materials. Any acidic material that does not interfere with subsequent processing steps may be employed whether it be organic or inorganic, although preferably organic acids of less than 6 carbon atoms and even more preferably acetic acid is employed.
  • the metal oxide precursor solution is added to the aqueous colloidal silica solution.
  • the metal oxide can be placed into an aqueous solution and then the two solutions blended to give a homogeneous solution.
  • the metal oxide can be a dispersion or solution of one or more ceramic metal oxides which include zirconium oxide, TiO 2 , Cr 2 O 3 , WO 3 , ThO 2 , Fe 2 O 3 , MgO, Y 2 O 3 , ZrO 2 , HfO 2 , V 2 O 5 , Nb 2 O 5 , UO 2 , BeO, CoO, NiO, CuO, ZnO, ln 2 O 3 , Sb 2 O 3 , A1 2 O 3 , Sn ⁇ 2 , and mixtures thereof such as ZnO ⁇ TiO 2 , TiO 2 ⁇ Fe 2 O 3 , SnO 2 ⁇ TiO 2 , Nd 2 O 3 -TiO 2 , A1 2 O 3 ⁇ C
  • dispersion or sols of said ceramic metal oxides in combination or admixture with dispersions or sols of one or more metal oxides which are unstable in normal air environment (such as Li 2 O, Na 2 O, K 2 O, CaO, SrO, and BaO) and/or ceramic nonmetal oxides having an atomic number of 14 or greater (such as SiO 2 , As 2 O 3 , and P 2 O 5 ) , representative combinations including A1 2 O 3 ⁇ Li 2 O, TiO 2 --K 2 O, ZrO 2 ⁇ CaO, ZrO 2 ⁇ Al 2 O 3 ⁇ CaO, ZrO 2 ⁇ SrO, TiO 2 ⁇ BaO, TiO 2 ⁇ ZrO 2 ⁇ BaO, Al 2 O 3 ⁇ Na 2 O, MgO ⁇ SiO 2 , Fe 2 O 3 ⁇ BaO, ZrO 2 - -Si
  • the metal oxide is selected from Periodic Table Group II or Group III metals.
  • a number of the above-described oxides useful in this invention are commercially available in the form of aqueous sols or dry powders which can be readily dispersed in water to form sols, such as Al 2 O 3 , Cr 2 O 3 and Fe 2 O 3 sols sold under the trademark "Nalco”, silica sols sold under the trademarks “Nalco,” “Ludox,” “Syton” and “Nyacol,” and Al 2 O 3 colloidal powder sold under the trademark "Dispal.”
  • the precursor material in the form of dispersion or sols of said oxides
  • the precursor material in the form of water soluble or dispersible inorganic or organic compounds which are calcinable to the corresponding oxide.
  • These compounds representatively include many carboxylates and alcoholates, e.g. acetates, formates, oxalates, lactates, propylates, citrates, and acetylacetonates, and salts of mineral acids, e.g., bromides, chlorides, chlorates, nitrates, sulfates, and phosphates, selection of the particular precursor compound being dictated by availability and ease of handling.
  • Representative precursor compounds useful in this invention include ferric chloride or nitrate, chromium chloride, cobalt nitrate, nickel chloride, copper nitrate, zinc chloride or carbonate, lithium propylate, sodium carbonate or oxalate, potassium chloride, beryllium chloride, magnesium acetate, calcium lactate, strontium nitrate, barius acetate, yttrium bromide, zirconium acetate, hafnium oxychloride, vanadium chloride, ammonium tungstate, aluminum chloride, indium iodide, titanium acetylacetonate, stannic sulfate, lead formate, antimony chloride, bismuth nitrate, neodymium chloride, phosphoric acid, cerium nitrate, uranium nitrate, and thorium nitrate.
  • the colloidal silica be a very fine particle size.
  • the silica concentration should be less than 50% and preferably approximately 10-30%, and even more preferably, about 20% by weight.
  • the purpose in adding the acidic material is to produce a negative electrostatic charge on the silica particles.
  • Colloidal silica particles exhibit a significant negative electrostatic charge in the ph range of from 3 to 5 and a value within this range is selected for matching with the ph of the aqueous metal oxide solution.
  • the ph adjusted colloidal silica solution are added to the slurry containing the metal oxide precursor solution and the mixture is stirred, preferably in the presence of ultrasonic treatment to facilitate the reaction.
  • the colloidal silica particles with a negative electrostatic charge are attracted to the positively charged metal ion (for example the zeta potential for zirconia at a ph of 3-5 is approximately 58-64 millivolts).
  • the ratio of silicon material to metal oxide is from 0.5 to 1.1 (silicon calculated as silicon dioxide) to 1 (metal oxide calculated as metal dioxide) mole ratio. Most preferably, the mole ratio is 1:1.
  • a mullite composition i.e., a metal oxide system that corresponds to three moles of Al 2 O 3 to two moles of SiO 2 .
  • the processing parameters are at ambient temperature and pressure and that the number of kilohertz ranges from
  • 0.1 to 1 kilohertz preferably less than 0.1 kilohertz, e.g. 0.05 to 0.07 kilohertz.
  • the concentration ranges from 10 to 60 wt%.
  • the viscosity of the solution ranges from 1 to 40 Centipoise (CPS).
  • the particles are subjected to a sintering or calcining treatment to obtain the desired ceramic particles.
  • the sintering temperature is at least 250° to 1500°, and even more preferably, about 900° to 1200oCentigrade.
  • FIG. 1 shows the schematic diagram of the apparatus useful in the present invention.
  • a tank 10 is a reservoir of the aqueous liquid 12.
  • the tank is open to the atmosphere at the top as indicated by arrows 14.
  • the tank is operated at ambient pressure.
  • a second tank 16 is one that likewise contains liquid 12 which passes from the tank 10 to the tank 16 by pipe 17.
  • the cavity 20 is one that is exposed to atmospheric pressure, for it is the cavity above the reservoir in the tank 10.
  • a similar cavity 22 is atop the reservoir 12 above the level 24 of the fluid in the reservoir 16.
  • the lower tank 16 likewise is open to the atmosphere as is indicated by arrow 26.
  • Line 18 maintains equal pressure in tanks 10 and 16.
  • the liquid transfer tube 28 is attached to nozzle means generally shown as reference numeral 30.
  • the inlet 32 for the liquid is placed adjacent to the air inlet 34 which is connected to an air pump generally expressed as 36.
  • the nozzle 30 is generally available from Spraying Systems, Inc. of Wheaton, Illinois, and is utilized in this invention as follows. When air from pump 36 passes through conduit 34 and air outlet 38, the liquid composition from reservoirs 12 and 24 pass through conduit 32 and is atomized into heated chamber 40. The spray nozzle 30 is locked in position by lock nut 42 onto an appropriately configured vessel 44. The top portion 46 of the nozzle is appropriately configured to lock in place at position 48 which is at the bottom of container 40.
  • the spray 50 from the air pump is schematically shown in Figure 1.
  • an atomized spray occurs whereby particulates are formed and subsequently become hollow spheres as the aqueous portion of the mixture is volatilized off in the heated chamber 40.
  • the particles are subsequently collected at a trough at the bottom (not shown) and the volatilized portion of the aqueous material is disposed of (apparatus not shown).
  • the reservoir level 24 drops.
  • the liquid 12 flows through pipe 17 into container 16 thereby increasing the level 24 to the point that it is just at the exit 52 of conduit 18.
  • the orifice 38 is preferably 0.016 inches in diameter and the orifice 33 of conduit 32, ranges from 0.05 inches for the inner diameter to 0.064 inches for the outer diameter or .007 inches.
  • the air is fed through conduit 34 at a range of 5 to 100 pounds per square inch gauge (psig), and even more preferably, 10 to 70 psig, most preferably, 15 to 30 psig.
  • Two of the interior walls of heat chamber 40 have four 500 watt strip heaters attached to black painted aluminum plates attached to the interior of the walls of the reservoir 40.
  • the heating of the chamber preferably exceeds 250oF, and even more preferably, 400° - 1000oF.
  • the non-spraying temperature would drop a minimum of 100oF during spraying.
  • the microspheres or particles that are produced preferably have a size less than 75 microns with a lower limit of approximately 1 micron.
  • the size range is preferably 10 to 60 microns, and even more preferably, 15 to 50 microns.
  • particles that are not hollow may be produced, although that is not the preferred product. This may be accomplished by modifying the processing conditions such as a lower drying temperature and a higher viscosity homogeneous solution that is spray-dried.
  • an alternative particle collection device can be anything commercially available such as a cyclone collection system with a separate system for separating and collating the particulates depending upon the sizes desired for particles.
  • the microspheres preferably will have a surface area greater than 75 square meters (m 2 ) per gram, preferably 150 square meters per gram and upwards of 250 square meters per gram.
  • Example 1 Colloidal silica (LudoxTM, trademark of E.I.
  • DuPont Company having an average particle diameter 7 nanometers with a ph of 9.9 is diluted with water to make a 21% by weight percent silica in the mixture.
  • the ph of the solution is adjusted to a ph in range of 3 to 5 by the addition of acetic acid.
  • a second slurry was prepared of zirconium acetate (21% by weight) which is stirred.
  • the ph adjusted colloidal silica solution is then added to the slurry containing zirconium acetate and stirred in the presence of ultrasonic equipment operating at 60 - hertz.
  • the SiO 2 :ZrO 2 is a 1:1 mole ratio.
  • the viscosity of the mixture was 4-5 CPS.
  • the mixture was then placed in a piece of equipment comparable to that shown in Figure 1. Air was pumped through nozzle 34 with the aqueous liquid being sucked through conduit 32 and likewise through conduit 28 from reservoir 12 and vessels 16 and 18.
  • the temperature of the vessel 40 was initially 400°F and during spraying decreased to approximately 275° to 300oF.
  • the particles were collected at the bottom and were subjected to sintering or drying. The particles were dried for 2 hours at 250° then at 650° for 2-4 hours until the powder is colorless and then for 2 hours at 1100"Centigrade.
  • the X-ray diffractogram of the sample calcined to 1100°C is shown in Figure 3.
  • the sample produced was tested at 500 ⁇ F using the guarded hot plate method where the density was 75 pounds per cubic foot having a thermal conductivity of 1.86 (btu-inches per hour - per square foot per degree Fahrenheit). Comparable experiments were conducted according to ASTM-C 177 for different temperatures ranging from 600°F to 1400°F.
  • the zircon samples were prepared by pouring the zircon material into Ceraboard (trademark of Manville Sales Corporation) rings with a glass cloth top and bottom. After the samples were tested, physical cracks with depths of 0.25+ inches were observed. The results are tabulated below.
  • Colloidal silica having an average particle diameter of 12 nanometers with a ph of 8.9 is diluted with water to solution that is 21% by weight percent silica. After dilution and stirring of the mixture, the ph of the solution is adjusted to a ph in range of 3 to 5.
  • a second slurry was prepared of zirconium oxychloride (Magnesium Elektron Co.), 21% by weight, which is stirred.
  • the ph adjusted colloidal silica solution is then added to the slurry containing zirconium oxychloride and stirred with a mechanical mixture.
  • the Si0 2 :Zr0 2 is a 1:1 mole ratio.
  • the viscosity of the mixture was 3-5 CPS.
  • the mixture was spray-dried and calcined the precursor hollow microspheres as described in Example 1.
  • Hollow microspheres were prepared in the same manner as in Example 1 except that zirconyl oxynitrate [ZrO(NO 3 ) 2 ] is used.
  • Example 4 Hollow microspheres were prepared in the same manner as in Example 1 except that 2% w/w of B 2 O 3 by the weight of zircon was added as boric acid to the precursor solution. In a separate beaker, take LudoxTM 18Og and to that add 180g (equal amount) of water. Then add 4-5g of acetic acid. Add this ph adjusted LudoxTM to a solution of 558. Ig aluminum oxychloride (50% by wt) in 500 ml ethanol. Mix thoroughly.
  • the solution was combined up to make approximately 5 gallons of precursor solution.
  • the spray-dried material was sintered at 250°C for 1 hour; 650°c for l hour and finally at 1000°C for 48 hours.
  • the oven was cooled to room temperature.
  • the products were tested by spectroscopic and X-ray diffraction tests for composition were determined to be mullite particles.
  • Hollow mullite particles were prepared in the same manner as in Example 5 except that % w/w of B 2 O 3 by the weight of mullite was added as boric acid to the precursor solution.
  • compositions herein can be used for insulation purposes and refractory purposes such a insulation of heated products or appliances, other end uses are thermal shields in space exploration equipment, missiles, rockets and in commercial and military aircraft for heat and/or fire protection in voice record box, engine parts, fuselage, and the like.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Silicates, Zeolites, And Molecular Sieves (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)

Abstract

Procédé de préparation de particules discrètes creuses en céramique consistant à procéder aux étapes suivantes: former une solution d'une matière contenant du silicium à un pH acide, former une solution précurseur aqueuse d'oxyde de céramique et de métal, former un mélange homogène de la solution de silicium et de la solution précurseur d'oxyde de céramique et de métal, sécher par pulvérisation la solution homogène par pulvérisation de ladite solution dans une chambre chauffée dans laquelle règne une pression au moins ambiante afin de former des particules, fritter lesdites particules et récupérer des particules d'oxyde de métal au silicium.
PCT/US1991/008979 1990-12-03 1991-12-02 Procede de preparation de particules creuses en ceramique WO1992009543A1 (fr)

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US62131390A 1990-12-03 1990-12-03
US621,313 1990-12-03

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WO1992009543A1 true WO1992009543A1 (fr) 1992-06-11

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0601594A1 (fr) * 1992-12-11 1994-06-15 Asahi Glass Company Ltd. Procédé pour la production de microballons cristallins
ES2074399A1 (es) * 1993-05-13 1995-09-01 Consejo Superior Investigacion Procedimiento de obtencion de pigmentos ceramicos de silicato de circonio.
WO2002038338A3 (fr) * 2000-11-10 2002-07-11 3M Innovative Properties Co Particules abrasives composites et procede de fabrication
US6881483B2 (en) 2000-10-06 2005-04-19 3M Innovative Properties Company Ceramic aggregate particles
US6913824B2 (en) 2000-10-16 2005-07-05 3M Innovative Properties Company Method of making an agglomerate particle
JP2015218071A (ja) * 2014-05-14 2015-12-07 太平洋セメント株式会社 微小ムライト中空粒子
JP2015229622A (ja) * 2014-06-06 2015-12-21 太平洋セメント株式会社 中空粒子の製造装置
JP2016017027A (ja) * 2014-07-11 2016-02-01 太平洋セメント株式会社 中空粒子の製造方法

Citations (6)

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Publication number Priority date Publication date Assignee Title
US3793041A (en) * 1969-05-16 1974-02-19 Minnesota Mining & Mfg Refractory fibers of zirconia and silica mixtures
JPS60161371A (ja) * 1984-02-01 1985-08-23 工業技術院長 高強度セラミツクス焼結体の製造法
JPS61122173A (ja) * 1984-11-15 1986-06-10 旭化成株式会社 無機多孔体とその製造方法
JPS6279841A (ja) * 1985-10-02 1987-04-13 Teikoku Kako Kk 無機球状体の製造方法
EP0224375A2 (fr) * 1985-11-22 1987-06-03 Minnesota Mining And Manufacturing Company Microsphères transparentes en oxyde de zirconium non-vitreux
JPH01183403A (ja) * 1988-01-13 1989-07-21 Idemitsu Kosan Co Ltd 複合化無機物粉末の製造方法

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Publication number Priority date Publication date Assignee Title
US3793041A (en) * 1969-05-16 1974-02-19 Minnesota Mining & Mfg Refractory fibers of zirconia and silica mixtures
JPS60161371A (ja) * 1984-02-01 1985-08-23 工業技術院長 高強度セラミツクス焼結体の製造法
JPS61122173A (ja) * 1984-11-15 1986-06-10 旭化成株式会社 無機多孔体とその製造方法
JPS6279841A (ja) * 1985-10-02 1987-04-13 Teikoku Kako Kk 無機球状体の製造方法
EP0224375A2 (fr) * 1985-11-22 1987-06-03 Minnesota Mining And Manufacturing Company Microsphères transparentes en oxyde de zirconium non-vitreux
JPH01183403A (ja) * 1988-01-13 1989-07-21 Idemitsu Kosan Co Ltd 複合化無機物粉末の製造方法

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Title
CHEMICAL ABSTRACTS, vol. 105, no. 16, October 1986, Columbus, Ohio, US; abstract no. 138654J, TAKEDA, KUNIHIKO: 'MANUFACTURE OF INORGANIC POROUS BODY' page 302 ;column R ; & JP-A-61122173 (10-06-1986) *
PATENT ABSTRACTS OF JAPAN vol. 13, no. 466 (C-646)20 October 1989 & JP,A,1 183 403 ( IDEMITSU KOSAN CO. LTD, JP ) 21 July 1989 *
WORLD PATENTS INDEX LATEST Week 8540, Derwent Publications Ltd., London, GB; AN 85-245846 & JP,A,60 161 371 (AGENCY OF IND. SCI. TECHN.) 23 August 1985 *
WORLD PATENTS INDEX LATEST Week 8720, Derwent Publications Ltd., London, GB; AN 87-140294 & JP,A,62 079 841 (TEIKORU KAKO) 13 April 1987 *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0601594A1 (fr) * 1992-12-11 1994-06-15 Asahi Glass Company Ltd. Procédé pour la production de microballons cristallins
ES2074399A1 (es) * 1993-05-13 1995-09-01 Consejo Superior Investigacion Procedimiento de obtencion de pigmentos ceramicos de silicato de circonio.
US6881483B2 (en) 2000-10-06 2005-04-19 3M Innovative Properties Company Ceramic aggregate particles
US6913824B2 (en) 2000-10-16 2005-07-05 3M Innovative Properties Company Method of making an agglomerate particle
WO2002038338A3 (fr) * 2000-11-10 2002-07-11 3M Innovative Properties Co Particules abrasives composites et procede de fabrication
US6645624B2 (en) 2000-11-10 2003-11-11 3M Innovative Properties Company Composite abrasive particles and method of manufacture
JP2008274293A (ja) * 2000-11-10 2008-11-13 Three M Innovative Properties Co 複合研磨剤粒子および製造方法
JP2015218071A (ja) * 2014-05-14 2015-12-07 太平洋セメント株式会社 微小ムライト中空粒子
JP2015229622A (ja) * 2014-06-06 2015-12-21 太平洋セメント株式会社 中空粒子の製造装置
JP2016017027A (ja) * 2014-07-11 2016-02-01 太平洋セメント株式会社 中空粒子の製造方法

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