WO2011147866A1 - Procédé de production d'une granulation en verre quartzeux - Google Patents

Procédé de production d'une granulation en verre quartzeux Download PDF

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Publication number
WO2011147866A1
WO2011147866A1 PCT/EP2011/058547 EP2011058547W WO2011147866A1 WO 2011147866 A1 WO2011147866 A1 WO 2011147866A1 EP 2011058547 W EP2011058547 W EP 2011058547W WO 2011147866 A1 WO2011147866 A1 WO 2011147866A1
Authority
WO
WIPO (PCT)
Prior art keywords
granules
bed
laser beam
quartz glass
granulate
Prior art date
Application number
PCT/EP2011/058547
Other languages
German (de)
English (en)
Inventor
Walter Lehmann
Thomas Kayser
Martin Trommer
Christian Nasarow
Original Assignee
Heraeus Quarzglas Gmbh & Co. Kg
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 Heraeus Quarzglas Gmbh & Co. Kg filed Critical Heraeus Quarzglas Gmbh & Co. Kg
Priority to DE112011101801.0T priority Critical patent/DE112011101801B4/de
Publication of WO2011147866A1 publication Critical patent/WO2011147866A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B19/00—Other methods of shaping glass
    • C03B19/10—Forming beads
    • C03B19/1095—Thermal after-treatment of beads, e.g. tempering, crystallisation, annealing

Definitions

  • the present invention relates to a method for the production of quartz glass grain by sintering a bed of free-flowing SiO 2 granules of porous granules by heating them and vitrifying them to form quartz glass particles.
  • Synthetic SiO 2 granules consisting of porous granulate particles are obtained by agglomeration and densification of amorphous SiO 2 powder, as obtained, for example, in the production of synthetic quartz glass in precipitation reactions or in CVD precipitation processes as soot or filter dust. Since the immediate utilization of the soot dust by melting is problematic because of the low bulk density, this is usually precompressed by conventional construction or pressing granulation process.
  • Examples which may be mentioned are roll granulation in a granulating dish, spray granulation, centrifugal atomization, fluidized-bed granulation, granulation processes using a granulating mill, compaction, roll pressing, briquetting, blank production or extrusion.
  • the resulting discrete, mechanically and optionally also thermally pre-compressed particles are thus composed of a multiplicity of primary particles and are referred to herein as "SiO 2 granulate particles.” In their entirety they form the porous "SiO 2 granulate”. Such porous "SiO 2 granulate" is easier to handle, but for
  • a generic method for vitrifying synthetic SiO 2 granules is known from EP 1 076 043. It is proposed to throw porous SiO 2 granules into a fuel gas flame in order to finely distribute it therein and to vitrify at temperatures of 2000 to 2500 ° C.
  • the granules are preferably obtained by spray or wet granulation of filter dust and has particle sizes in the range of 5 to 300 ⁇ . Before vitrification, it can be heated and precompressed by treatment with microwave radiation.
  • an SiO 2 gel is prepared by the polymerization of tetramethoxysilane by the sol-gel method and dried rapidly in vacuo, so that it breaks up to form SiO 2 granules.
  • the granules are then filled into a sintered container made of quartz glass and sintered in batches in an electrically heated furnace. For this - - The granules are heated at a heating rate of 200 ° C / h to 1 150 ° C and held at this temperature for 35 hours.
  • US 2004/0237588 A1 describes a method for vitrifying a SiO 2 green body, which is obtained by a slip casting method, by irradiation with a laser under vacuum or helium.
  • WO 00/44679 A1 a method for laser Verg lase fine aggregated nanoparticles (aerosils) is known, which are generated for example by flame hydrolysis and are glazed directly after their formation by means of laser.
  • the invention is therefore based on the object of specifying a method which, starting from porous SiO 2 granules, enables a continuous and inexpensive production of transparent synthetic quartz glass grains having a low hydroxyl group content.
  • Optionally trapped gases consist of at least 50 vol .-% of helium, with proportions of hydrogen up to 50 vol .-%, which can also easily diffuse out in the further processing of vitrified quartz glass grain, and small amounts of other gases (up to about 5 vol. %) are harmless.
  • a laser beam or several laser beams are used for heating the granulate particles.
  • the at least one laser beam is focused on the granulate bed. This results in a locally high temperature on the granules without these being influenced mechanically (by blowing) or chemically (by impurities) by a fuel gas.
  • the granulate thus does not dodge and it is not loaded with any impurities of a fuel gas.
  • the local heating by means of laser beam only the irradiated bed area is heated and vitrified, so that the granules in the meantime repeatedly cool, which on the one hand reduces sintering together with adjacent particles and caked, and on the other hand contributes to a low thermal inertia of the process.
  • the method is also continuously carried out.
  • the relative movement between bed and laser beam can be done by continuous movement of the laser, optical deflection of the laser beam such as an oscillating reciprocation. According to the invention, however, a movement of the bed of granules is provided by the
  • the carrier is, for example, a pipe, a crucible, a gutter, a plate or a disk.
  • the movement of the bedding is generated by continuously moving the support or granulate bed, such as - - by tumbling, shaking, spinning or stirring. It is essential that the granules are moved relative to the laser beam and the granulation while the net weight of the bed is subjected. The resulting mechanical action contributes to the separation of agglomerated granules.
  • the angle of incidence between the laser beam and the bed is preferably less than 50 degrees. As a result, a larger surface area of the bed is heated and glazed compared to the vertical incidence.
  • the rotary tube is slightly inclined in the longitudinal direction, in order to bring about a transport of the granules from its inlet side to the outlet side.
  • the granulate bed is continuously circulated in the rotary kiln.
  • grain which is in contact with the rotary tube wall is continuously transported to the rotary tube center on the upper side of the bed in the laser beam and heated and glazed. From there, the wholly or partially glazed grain passes into the interior of the bed or under the bed as it is circulated, and cools down rapidly, while at the same time being exposed to mechanical forces which are exerted by the bed
  • Weight and the circulation of the bedding are generated. Any agglomerates of the glazed grain are dissolved again.
  • the granules outside the action of the laser beam and the inner wall of the rotary tube remain relatively cool.
  • the low thermal load on the rotary kiln wall results in a low removal and entry - - of impurities in the granules.
  • the comparatively cooler surface of unirradiated granule particles reduces the risk of sticking and caking.
  • the rotary tube is preferably arranged in a vacuum chamber, so that there are no difficulties in sealing the inlet and outlet ends of the rotary tube.
  • the granules For a uniform as possible vitrification of the granules about the same residence times in the area of the incident surface of the laser beam or the laser beams on the bed surface and about the same particle sizes are advantageous. In view of this, it has been found to be useful if the granules have a narrow particle size distribution at which the particle diameter assigned to the D 90 value is at most twice as large as the particle diameter assigned to the D 0 value.
  • a narrow particle size distribution shows a comparatively low bulk density, which counteracts agglomeration during desalination.
  • the weight difference between the particles as a parameter for any separation within the bed, which promotes more uniform vitrification of the bed is eliminated. It has proven to be advantageous to preheat the granules before glazing by means of a heater to a temperature of 800 ° C to 1200 ° C.
  • the granules are not or not appreciably vitrified; However, it results in a faster and energetically favorable vitrification when exposed to the laser beam.
  • the preheating is preferably carried out in an externally heated chamber into which the laser beam is directed for vitrifying the granules.
  • the preheating of the granules takes place in the same Kannnner as the vitrification, so for example a rotary kiln.
  • the chamber is maintained, for example, by electrical heating at a temperature which produces a temperature in the granular bed in the said range.
  • the chamber has an inner wall made of quartz glass.
  • the quartz glass particles can be contaminated by abrasion of the material of the chamber wall. This risk of contamination is counteracted by a chamber inner wall 10 made of quartz glass.
  • a method variant has proven in which the laser beam has an energy density sufficient to heat them when hitting a temperature of at least 1400 ° C.
  • the laser beam is generated by means of a CO 2 laser and at the point of impact on the bed has a focal spot with a diameter of at least 30 mm and a surface power of at least 40 W / cm 2 .
  • FIG. 1 shows a rotary kiln for carrying out the method according to the invention in a side view.
  • FIG. 1 shows a vacuum chamber 1 with a connection 2 to a vacuum pump, within which a rotary kiln 3 is mounted on rollers 4. At the outlet end 5 of the rotary kiln 3, a discharge housing 6 is arranged.
  • the inner wall of the rotary kiln 3 is lined with a quartz glass tube.
  • a resistance heater 10 is provided, by means of which a bed of 1 1 of SiO 2 granules can be heated to a temperature of 1 100 ° C.
  • CO 2 laser 8 type TLF 3000 Turbo
  • the primary beam is expanded in each case by means of an expanding optics to laser beams 12a, 12b, which are directed in the middle of the rotary tube 3 in grazing incidence on the granular bed 1 1, each with an oval focal spot with a diameter of 20 mm and a maximum area performance of about 50 W / cm 2 .
  • the angles of incidence between the surface of the granulate bed 1 1 and the respective laser beam 12a; 12b differ slightly and are between 20 and 30 degrees.
  • the evacuated (200 mbar) and rotating about its axis of rotation at 8 rev / min rotary kiln 3 is continuously supplied with a feed rate of 15 kg / h amorphous, porous SiO 2 granules.
  • the granules are obtained by granulation of pyrogenically produced, nanoscale SiO 2 powder and consists essentially of porous, spherical granules 13 having a particle size distribution with a D 10 value of 300 ⁇ m, a D90 value of 500 mm and an average particle Diameter (D50 value) of 400 ⁇ . - -
  • the rotary tube 3 is inclined in the longitudinal direction in the specific angle of repose of the granules 13, so that over its length a uniform thickness of the granulate bed 1 1 sets.
  • the granulate 13 is heated within the rotary kiln 3 to a temperature around 1 100 ° C, wherein the open porosity remains.
  • the vitrification of the granules 13 takes place when the laser beams 12a, 12b strike.
  • the preheated granulate bed 1 1 is continuously circulated and thereby to the rotary kiln center in the region of the laser beams 12 a; 12b and glazed. Due to the locally acting laser beams 12a, 12b comparatively few granules are softened. The temperature of the surrounding granules 13 hardly increases. In this way, caking between the granules 13 with each other are largely avoided. If agglomerates nevertheless occur, they are redissolved as a result of the mechanical stress in the moving granulate bed 11. Granulate particles 13 which come into contract with the wall of the rotary tube are also relatively cool (not hotter than 1100 ° C.), so that no adhesion to the quartz glass lining occurs.
  • the particles which are completely glazed on the quartz glass particles are continuously removed by means of the discharge device 6.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Glass Melting And Manufacturing (AREA)

Abstract

L'invention concerne un procédé de production d'une granulation en verre quartzeux par vitrification d'une charge de granulés de SiO2 coulants composés de particules de granulés poreux, selon lequel ces particules sont chauffées puis vitrifiées pour obtenir des particules de verre quartzeux. Pour permettre, à partir des granulés de SiO2 poreux, une production continue et économique d'une granulation en verre quartzeux synthétique transparent à faible teneur en hydroxyle, l'invention propose que la vitrification des particules de granulés poreux s'effectue sous vide ou dans une atmosphère contenant de l'hélium par l'intermédiaire d'au moins un faisceau laser, la charge de granulés étant versée sur un support et étant, lors de la vitrification, déplacée en continu par rapport au faisceau laser, à l'aide dudit support ou bien sur ledit support; les particules de granulés présentant une granulométrie comprise entre 200 et 1000 μm et le faisceau laser étant dirigé sur le versement de granulés dans une incidence rasante.
PCT/EP2011/058547 2010-05-27 2011-05-25 Procédé de production d'une granulation en verre quartzeux WO2011147866A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE112011101801.0T DE112011101801B4 (de) 2010-05-27 2011-05-25 Verfahren zur Herstellung von Quarzglaskörnung

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102010021693A DE102010021693A1 (de) 2010-05-27 2010-05-27 Verfahren zur Herstellung von Quarzglaskörnung
DE102010021693.3 2010-05-27

Publications (1)

Publication Number Publication Date
WO2011147866A1 true WO2011147866A1 (fr) 2011-12-01

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PCT/EP2011/058547 WO2011147866A1 (fr) 2010-05-27 2011-05-25 Procédé de production d'une granulation en verre quartzeux

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DE (2) DE102010021693A1 (fr)
WO (1) WO2011147866A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012006914B4 (de) * 2012-04-05 2018-01-18 Heraeus Quarzglas Gmbh & Co. Kg Verfahren zur Herstellung synthetischer Quarzglaskörnung
CN104185613B (zh) * 2012-04-05 2017-05-03 赫罗伊斯石英玻璃股份有限两合公司 用于由电熔化的合成的石英玻璃制造成形体的方法
EP3739283B1 (fr) 2019-05-17 2022-02-23 Heraeus Quarzglas GmbH & Co. KG Procédé de traitement du grain coulant inorganique ainsi que tube rotatif permettant la mise en oeuvre dudit procédé

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02284640A (ja) * 1989-04-26 1990-11-22 Nariyuki Furuta 燒結セラミックス微粉末の製造方法
US5604163A (en) 1994-07-11 1997-02-18 Mitsubishi Chemical Corporation Synthetic silica glass powder
JPH10287416A (ja) * 1997-04-08 1998-10-27 Mitsubishi Chem Corp 合成石英粉の製造方法
WO2000044679A1 (fr) 1999-01-27 2000-08-03 Man Soo Choi Procede de fabrication et de depot de particules fines par combinaison de flamme et d'un rayon laser
WO2001008795A1 (fr) * 1999-08-02 2001-02-08 Choi Man Soo Procede de fabrication de fines particules par faisceau laser
EP1076043A2 (fr) 1999-08-13 2001-02-14 Heraeus Quarzglas GmbH & Co. KG Procédé de fabrication de granules denses en verre de quartz
EP1088789A2 (fr) 1999-09-28 2001-04-04 Heraeus Quarzglas GmbH & Co. KG Granules poreux en silice, leur procédé de fabrication et leur utilisation dans un procédé de fabrication de verre de quartz
US20040237588A1 (en) 2003-05-28 2004-12-02 Wacker-Chemie Gmbh Method for the production of an internally vitrified SiO2 crucible

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02284640A (ja) * 1989-04-26 1990-11-22 Nariyuki Furuta 燒結セラミックス微粉末の製造方法
US5604163A (en) 1994-07-11 1997-02-18 Mitsubishi Chemical Corporation Synthetic silica glass powder
JPH10287416A (ja) * 1997-04-08 1998-10-27 Mitsubishi Chem Corp 合成石英粉の製造方法
WO2000044679A1 (fr) 1999-01-27 2000-08-03 Man Soo Choi Procede de fabrication et de depot de particules fines par combinaison de flamme et d'un rayon laser
WO2001008795A1 (fr) * 1999-08-02 2001-02-08 Choi Man Soo Procede de fabrication de fines particules par faisceau laser
EP1076043A2 (fr) 1999-08-13 2001-02-14 Heraeus Quarzglas GmbH & Co. KG Procédé de fabrication de granules denses en verre de quartz
EP1088789A2 (fr) 1999-09-28 2001-04-04 Heraeus Quarzglas GmbH & Co. KG Granules poreux en silice, leur procédé de fabrication et leur utilisation dans un procédé de fabrication de verre de quartz
US20040237588A1 (en) 2003-05-28 2004-12-02 Wacker-Chemie Gmbh Method for the production of an internally vitrified SiO2 crucible

Also Published As

Publication number Publication date
DE102010021693A1 (de) 2011-12-01
DE112011101801A5 (de) 2013-05-02
DE112011101801B4 (de) 2015-06-11

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