EP1991506A1 - Procédé et dispositif de protection contre la corrosion d'électrodes par l'influence de la température d'une fonte - Google Patents

Procédé et dispositif de protection contre la corrosion d'électrodes par l'influence de la température d'une fonte

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Publication number
EP1991506A1
EP1991506A1 EP07702929A EP07702929A EP1991506A1 EP 1991506 A1 EP1991506 A1 EP 1991506A1 EP 07702929 A EP07702929 A EP 07702929A EP 07702929 A EP07702929 A EP 07702929A EP 1991506 A1 EP1991506 A1 EP 1991506A1
Authority
EP
European Patent Office
Prior art keywords
melt
heating
electrodes
electrode
arrangement
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP07702929A
Other languages
German (de)
English (en)
Inventor
Olaf Claussen
Thomas Stelle
Volker Ohmstede
Thomas Pfeiffer
Michael Hahn
Klaus-Dieter Duch
Ralf-Dieter Werner
Sylvia Biedenbender
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Schott AG
Original Assignee
Schott AG
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 Schott AG filed Critical Schott AG
Publication of EP1991506A1 publication Critical patent/EP1991506A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/167—Means for preventing damage to equipment, e.g. by molten glass, hot gases, batches
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/02—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture in electric furnaces, e.g. by dielectric heating
    • C03B5/027—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture in electric furnaces, e.g. by dielectric heating by passing an electric current between electrodes immersed in the glass bath, i.e. by direct resistance heating
    • C03B5/03—Tank furnaces
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/167—Means for preventing damage to equipment, e.g. by molten glass, hot gases, batches
    • C03B5/1672—Use of materials therefor
    • C03B5/1675—Platinum group metals
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/167—Means for preventing damage to equipment, e.g. by molten glass, hot gases, batches
    • C03B5/1677—Means for preventing damage to equipment, e.g. by molten glass, hot gases, batches by use of electrochemically protection means, e.g. passivation of electrodes
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/18—Stirring devices; Homogenisation
    • C03B5/182—Stirring devices; Homogenisation by moving the molten glass along fixed elements, e.g. deflectors, weirs, baffle plates
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/18—Stirring devices; Homogenisation
    • C03B5/183—Stirring devices; Homogenisation using thermal means, e.g. for creating convection currents
    • C03B5/185—Electric means
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/42—Details of construction of furnace walls, e.g. to prevent corrosion; Use of materials for furnace walls
    • C03B5/43—Use of materials for furnace walls, e.g. fire-bricks
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D11/00—Arrangement of elements for electric heating in or on furnaces
    • F27D11/02—Ohmic resistance heating
    • F27D11/04—Ohmic resistance heating with direct passage of current through the material being heated
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/02—Details
    • H05B3/03—Electrodes
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2211/00—Heating processes for glass melting in glass melting furnaces
    • C03B2211/70—Skull melting, i.e. melting or refining in cooled wall crucibles or within solidified glass crust, e.g. in continuous walled vessels

Definitions

  • the invention relates to a method for influencing the temperature of a melt, in particular a method for refining and / or cleaning of melts according to the preamble of claim 1.
  • the invention also relates to a device for influencing the temperature and / or for refining and / or purification of melts according to the preamble of Claim 48 and a product, in particular a glass product which has been melted and / or purified and / or purified and / or produced according to the inventive method and / or in the device according to the invention.
  • the starting material the so-called glass batch is melted down.
  • the melting takes place in tubs and is usually limited due to the thermal load capacity of the wall material to melting temperatures up to 1650 0 C. After the mixture has become liquid with increasing temperature, begins in the glass
  • the refining begins in a second process step. This can be done in a so-called fining chamber. In the refining chamber, the melt is thoroughly mixed and degassed to improve homogeneity and to remove bubbles. An essential goal in refining is to release and remove the gases physically and chemically bound in the melt.
  • melt gases The origin of occurring in the melt gases is' the raw materials and the surrounding melt atmosphere. The largest amount falls on water, other gases that can be found in the glass are SO 2 , CO 2 and N 2 . The majority of these gases are dissolved in the glass chemically or physically dissolved, a small, but decisive for the glass quality remainder exists as a dispersion of minute bubbles. In addition, all glasses contain appreciable amounts of chemically bound oxygen. The most important carriers are on the one hand polyvalent
  • Impurities of the glass e.g. Iron (III) oxide, and on the other oxidic refining agents such as As (V) oxide or Sn (IV) oxide.
  • As (V) oxide or Sn (IV) oxide oxidic refining agents
  • water is also one of these compounds.
  • Hydrogen is permeable, the migration of hydrogen at the interface between precious metal • and glass melt to an enrichment of oxygen to the formation of small bubbles can lead to their inclusion in the glass melt can significantly affect the quality of the glass products produced.
  • the necessary for the formation of bubbles driving force is based on a temporary supersaturation of the refining gas, the corresponding oxygen or gas partial pressure is at least 1 bar, depending on the type of melt and up to 5 bar.
  • the cause of this supersaturation is usually a temperature increase.
  • the state of supersaturation is then depending on the melt, refining agent, melting process, cullet, etc. from a respective characteristic minimum temperature, the so-called refining temperature, a.
  • melts above the refining temperature, the melt is unstable against a spontaneous formation of new bubbles, which thus competes with the reduction of supersaturation against the actually intended enlargement of the bladder.
  • the situation is therefore exacerbated for melts that are on the one hand highly supersaturated, and on the other hand also have only a low bubble load, as is the case with pre-skimmed melts.
  • the transport of these gases takes place diffusively from the gas volume to the bubble edges.
  • the necessary chemical driving force is based on the temporary supersaturation of the refining gas.
  • the corresponding gas partial pressure is at least 1 bar, possibly even up to 5 bar.
  • the trigger of this supersaturation is usually a temperature increase. In this case, it is important to follow the "Bladder Enlargement" refining step with an ascent zone that filters out not only the inflated blisters but also the neoplasms.
  • the interfacial tensions at the 3-phase interface metal / glass / bubble are of crucial importance.
  • this structure is highly glass- and electrode-specific; on the other hand, the chemical composition of the electrode surface can be controlled very strongly by redox processes.
  • oxidation can lead to the formation or reinforcement of metal oxide layers. This leads to the formation of passivating Mo ⁇ 2 ⁇ layers on the surface of a molybdenum electrode.
  • a reduction can lead to the degradation of oxide films to alloying with glass components, such as the formation of MoSi 2 layers on molybdenum electrodes.
  • Electrode via the formation of ions or their cathodic destruction by transformation into their liquid alloy phase. Analogous to the corrosion protection of iron alloys in aqueous media, the phenomenon of passivation is also known for electrodes in glass contact.
  • alloying constituents such as, for example, silicon or zirconium in molybdenum
  • Precious metal walls especially of platinum-rhodium alloys, have in glass contact other special bubbling mechanisms based on the exchange of hydrogen between the platinum in which it is atomically soluble and the glass in which it is bound as water.
  • oxygen production converts into oxygen bubble formation.
  • the water decomposition corresponds to a currentless Anodic polarization of the noble metal electrode.
  • Corrosion processes and blistering on the surfaces of the electrodes are in addition to the temperature-controlled gas supersaturation in addition by the factors electrode material, electrode composition, surface texture, temperature gradients, local Current density and frequency of the heating current, local load with direct currents as well as possibilities for hydrogen flows in the electrode affected.
  • the content of water and refining agents as well as the redox state play an essential role.
  • High-viscosity glass melts especially those of the type of alkali-free glasses, AF glasses, require very high refining temperatures. If temperatures of above 1700 ° C. are required and if these are to be produced by electrical heating by means of electrodes, then the use of Pt or platinum-rhodium alloys is forbidden; above 1800 ° C., molybdenum and tungsten are also eliminated. In principle, only iridium is considered as an electrode material. Special alloys are currently not available.
  • the viscosity of the molten glass is reduced and the rate of ascent of the bubbles in the melt is increased.
  • refining agents Another starting point is the use of so-called refining agents.
  • the principle of this refining agent is to add to the melt, in particular the molten glass, substances which decompose at high temperatures with gas release (for example from oxygen).
  • gas release for example from oxygen
  • the gases suddenly released by the refining agents first enlarge the small bubbles present, which in a second step "collect” the gases in the melt are able to leave the melt.
  • the choice of the refining agent depends primarily on the temperature of the molten glass during the refining. While the refining agent arsenic pentoxide As 2 O 5 already decomposes at temperatures above 1250 0 C in arsenic As 2 O 3 and oxygen, decomposes the Hochtemperaturläuterstoff SnO 2 only at temperatures above 1500 0 C in SnO and O 2 . However, the resulting oxides remain in the melt and can be detected in the final glass product. Arsenic present in the final glass product is particularly disadvantageous if ecologically harmless glasses are desired. A disadvantage of using refining agents such as As, Sb, Sn oxide is that they promote the corrosion of molybdenum and tungsten electrodes. Below 1800 0 C it comes to the formation of thin
  • Metal oxide films that act like an automatic passivation are, however, noticeably weakened, depending on the glass composition with rising temperatures and above 1800 0 C are molybdenum and tungsten without protection exposed to the corrosive attack by the dissolved oxygen in the glass.
  • the heating of the glass melt is done conventionally by oil or gas burners, which are located in the upper furnace.
  • the heat is introduced here via the glass surface.
  • additional heating in particular with low-absorbing glasses, additional electrical heating by means of electrodes takes place.
  • the molten glass is conductively heated with alternating current, that is, it is heated directly.
  • the electrodes are attached to the bottom or side walls of the vessel for this purpose and are in direct contact with the molten glass.
  • Molybdenum, platinum and metals of the platinum group are mainly used as the electrode material. In the conventional mode of operation or in known devices, however, these materials are also a possible corrosion especially exposed by aggressive silicate melts. Molybdenum electrodes therefore have a strong tendency to oxidize. They must therefore be protected during the starting process by an inert gas atmosphere. Also, some of the melted oxides, such as As 2 O 5 , molybdenum or platinum electroders, can attack. Although platinum electrodes are significantly more inert than molybdenum electrodes, they can only be used for temperatures up to 1500 ° C. for longer periods of time.
  • the document US 4246433 describes the use of cooled, in particular water-cooled, rod electrodes which are introduced through the side walls into a melting vessel.
  • water cooling By water cooling, the stability of the electrode against corrosion at higher temperatures is still guaranteed, so higher temperatures can be set in the melt, without having to accept a breaking or deformation of the electrodes. Therefore, the maximum achievable melting temperature is no longer limited by the application limit temperature of the electrode material by the cooling.
  • Board entry of ionic or elemental metal into the molten glass may, depending on the concentration and particle size in the glass end product, lead to undesired discoloration and reduced transmission of the electromagnetic radiation.
  • the document DE 19939780 A1 describes the continuous refining of glasses in units in which the melt is heated by direct coupling of high-frequency energy.
  • the aggregate used in this case consists of cooling circuits, which are almost “invisible” to the high frequency radiation used to heat the melt. At these cooled walls of the aggregate, the melt solidifies and forms a so-called skull layer between the molten glass and the
  • An advantage of high frequency melting in such skull crucibles is that glass melts can be heated to temperatures above 1700 0 C, since the temperature resistance of the aggregate wall is no longer a limiting factor due to the formed by the cooling skull layer. Due to the direct coupling of the high frequency into the glass melt, the melt in the edge region of the melting unit may be colder than in the middle.
  • the skull layer can melt and refine high-melting and highly corrosive glasses.
  • the heating of the melt by means of high frequency has the disadvantage that the melting glasses, glass ceramics, ceramics or crystals must have a sufficiently high electrical conductivity at the melting temperature, so that the registered using the high frequency energy is greater than that on the skull walls dissipated amount of heat.
  • the electrical conductivity of glass and glass ceramic melts is generally determined by the alkali content and, to a lesser extent, the alkaline earth content of these melts.
  • Conductivity also depends on a number of apparatus parameters, it has been found in practice that the electrical conductivity of the melt should be above 10 "1 Q -1 Cm " 1 . In practical experiments has been found, however, that in particular the high-melting glasses for which the high-frequency melting in the skull crucible due to high temperatures would be particularly suitable, has a too low electrical conductivity, in particular of less than 10 "1 Q -1 cm '1. Thus, with the high frequency melting technique, a number of important technical glasses can not be processed.
  • the glasses with low electrical conductivity and high temperature resistance include, in addition to glasses, which are required for pharmaceutical packaging and high-temperature resistant lamps, also glasses, such as display glasses, which are coated in the further processing process.
  • glasses such as display glasses, which are coated in the further processing process.
  • display glasses even the smallest alkali contents are undesirable because these metals can easily diffuse out of the glasses and thus reach the functional layers of the display.
  • These glasses also have due to the low or non-existent alkali content too low electrical conductivity in order to couple well enough with 'the high frequency.
  • PCT / EP 03/13353 describes a method and a device for heating melts.
  • a glass melt is heated by flowing a current between at least two again cooled electrodes, the electrodes each replacing a part of the wall of the melting vessel.
  • the wall of the melting vessel is described in the
  • the published patent application DE 198 02 071 A1 describes a method for heating glass melt aggregates in which a direct current component is impressed on the alternating current serving to heat the melt, in order to considerably reduce the corrosion of the electrode material used. In this case, an additional voltage drop is generated in one of the two partial currents of the alternating current in a heating circuit containing a transformer and at least two electrodes projecting into the molten glass.
  • the application further describes a positive and a negative connected electron series, wherein on the negatively connected electrode row, especially the removal of the electrode material in the melt and on the positively connected electrode row, especially the formation of possibly liquid alloys is suppressed.
  • the disadvantage is that at the positively connected electrode row, a removal of the electrode material is not prevented in the melt.
  • melt lie In addition, this method ensures that heavy metal ions contained in the melt are discharged at the electrodes and form a protective layer there. Thus, the corrosion of the electrodes is prevented by the aggressive melt.
  • the object of the present invention is to provide a possibility for influencing the temperature of a melt, in particular for refining and purifying melts, as well as a product, which has been melted and / or purified and / or purified and / or produced according to the invention, while largely avoiding the above-mentioned disadvantages.
  • the object comprises the aim of enabling a refining of the melt at temperatures higher than 1700 ° C. and at least to reduce the use of refining agents in the melt and, in particular, to minimize the amount of refining agents in order largely to control toxic substances such as, for example, AS 2 O 5 to be able to do without. Also, despite high temperature, the entry of ions from the melt contact surface of the wall and the electrode of the device should be minimized.
  • the invention provides a method for
  • Temperature influencing a melt in a space defining a receiving melt-defining arrangement in particular in a melting and / or Läuterü available, in which at least two heating electrodes are arranged in contact with the melt for heating the melt at least by ohmic resistance heating, and at least one Counter electrode is provided, and at least one heating electrode opposite to the counter electrode is set at a potential at which surface reactions of the heating electrode material with reactants from the melt are reduced.
  • the electromagnetic energy for heating the melt can advantageously be coupled particularly easily to the material to be melted.
  • Heating electrode and the counter electrode the electrodes are sufficiently protected against corrosion.
  • the proportion of gas bubbles in the melt is advantageously minimized by the blistering on the heating electrodes is already greatly reduced by the inventive method compared to the implementation without the application of the potential.
  • the invention provides, the potential by applying a DC voltage between the at least one
  • the surface of the heating electrodes shows a high gloss, lowest roughness and a high wettability with molten glass.
  • a heating current there is advantageously essentially no removal of particles of the electrode material into the melt, which results in a long-term stabilization of the heating electrodes. Due to the realizable with the help of the invention
  • Gas bubbles do not or only very poorly adhere to the surface of the electrode material, which allows a very early detachment of minute, newly formed bubbles.
  • the melt is cooled, which may be located for example in an edge region surrounding the process treated melt, the possibility is advantageously created, lower where the melt can come into contact with melt-carrying components, so that the risk of corrosion and / or entry of components of such components in the melt can be reduced.
  • a crust of solidified, the melt-inherent material, a so-called Skulltik be formed, which forms a vessel in which the melt is treated.
  • the melt is advantageously in an environment of species-specific material in which the risk of contamination is largely reduced.
  • various process steps can take place side by side in the method according to the invention, in particular at elevated temperature.
  • more can Melting processes take place on the other hand, the refining of the melt can take place. wherein in addition to gas bubbles and the product properties of the later glass negative affecting substances can be removed, that is, the melting and / or refining a cleaning step can be superimposed.
  • the invention further provides for carrying out the method in such a way that the melt is provided in the arrangement defining a space for receiving a melt, in particular a vessel, the arrangement being cooled at least in regions.
  • the arrangement can be formed, for example, by lines, in particular pipelines, through which a coolant can flow.
  • the term "arrangement" thus includes any structure which can at least temporarily receive the melt. These include, in particular, vessels, such as refining units and / or melting tanks.
  • the cooling surface of the side walls and thus the cooling effect increase in an advantageous manner. This will be during the
  • the self-adjusting temperature profile also produces an advantageous convection in the vessel, whereby the introduced into the melt energy is introduced evenly into the melted or molten material.
  • the invention enables an energy-efficient influencing of the temperature of a melt.
  • the electromagnetic energy for heating the melt is particularly easily coupled to the material to be melted.
  • particularly high temperatures can be realized in the melt.
  • This is made possible by the arrangement of the at least two electrodes in the space of the vessel, which advantageously increases the cooling surface of the side walls and thus the cooling effect on the melt.
  • the entire side walls are covered with a crust of solidified, species-specific material, whereby the vessel walls are protected against attack of the melt, and the melt itself against material input from the side of the vessel wall.
  • the entire side walls are covered with a crust of solidified, species-specific material.
  • the skull layer which permanently renews during operation reduces an attack on the wall of the unit and reduces the material input into the molten glass and thus also into the final glass product.
  • a wall material can be used because of the skull layer in an advantageous manner much cheaper materials such as copper instead of the otherwise commonly used expensive platinum.
  • a temporally constant potential is applied between the at least one heating electrode and the counterelectrode in order to maintain the same operating parameters over the entire duration and to reliably avoid the corrosion of the electrodes.
  • the possibility of temporarily between the at least one heating electrode and the counter electrode constant over time Potential to create This means that, over a certain period of time, a potential that is constant over time in this period is applied.
  • a temporary application of a temporally constant potential is particularly suitable when a "memory effect" of the heating electrodes exists after the application of the potential.
  • a memory effect is exhibited, for example, by heating electrodes which comprise iridium and which have been cathodically polarized in that, after the potential between the heating electrodes and the counter electrode has been removed, corrosion of the heating electrodes, which would otherwise be observed without the potential, does not occur, especially over several days.
  • the method according to the invention can be carried out by applying a voltage between the at least one heating electrode and the counterelectrode such that the potential of the heating electrode is in the range of greater than or equal to 50 mV to less than or equal to 500 mV, especially preferably lowered from 300 mV (deviations of up to 10% are not critical).
  • Heating electrode potential is relative to the reference electrode '.
  • the voltages to be applied between the heating and counterelectrode can be considerably larger differ, especially if the corresponding electrolyte resistance of the melt is high.
  • the desired passivation state of the heating electrode is represented by applying a well-defined direct current density.
  • the corresponding direct current is then measured between the heating and counterelectrode.
  • the relationship between the DC load and the associated DC potential shift can be determined in the laboratory. The characteristic thus created then serves for setting the passivation status locally.
  • a cathodic polarization with an amount of 50 mV may be sufficient, which may be even smaller, for example 20 mV, depending on the current flow.
  • a cathodic potential shift of an amount of 300 mV can be selected.
  • the potential to be applied reflects the conditions at the interface between iridium and glass with little iridium.
  • Iridium usually consists of an alloy that can always have significant levels of impurities due to base compounds such as some 100 ppm to 1000 ppm of molybdenum, tungsten and zirconium. These impurities are electrochemically effective and determine the potential that sets in a melt.
  • base compounds such as some 100 ppm to 1000 ppm of molybdenum, tungsten and zirconium.
  • These impurities are electrochemically effective and determine the potential that sets in a melt.
  • the application of a potential prevents the formation of a layer of iridium oxide on the heating electrodes, with the result that the electrodes are not attacked even by strongly alkaline melts
  • a local direct current density of less than or equal to 100 ⁇ A / cm 2 preferably of smaller or equal to metallic components of the arrangement, in particular to the heating electrodes and / or the counter electrode and / or the side wall and / or the bottom plate equal to 50 uA / cm 2 , adjusted and / or controlled and / or regulated, since it has been found that then blistering can be particularly reliably prevented.
  • electrodes can be used, which in particular as a melt contact material osmium, hafnium, molybdenum, tungsten, platinum, iridium, platinum metals and / or which
  • an electrode which comprises molybdenum, tungsten, platinum or alloys of the aforementioned elements.
  • the invention advantageously provides for arranging the counterelectrode in an overflow and / or floor drain of the arrangement.
  • the counterelectrode may advantageously be arranged in a flow dead zone of the arrangement.
  • the invention offers various possibilities, depending on the electrochemical relationships between the materials of the melt and the heating electrodes and optionally further metallic components of the arrangement to apply differently directed potentials.
  • the counter electrode can be connected as an anode.
  • the heating electrodes can be switched as cathodes. It is also within the scope of
  • the melt is heated via the heating electrodes with alternating current, preferably with an alternating current frequency in a frequency range of greater than or equal to 1 kHz to less than or equal to 100 kHz, particularly preferably with an alternating current frequency of 10 kHz ⁇ 3 kHz, in particular 8 kHz heated.
  • alternating current preferably with an alternating current frequency in a frequency range of greater than or equal to 1 kHz to less than or equal to 100 kHz, particularly preferably with an alternating current frequency of 10 kHz ⁇ 3 kHz, in particular 8 kHz heated.
  • the electrodes are separately controllable and / or controllably and / or adjustably cooled.
  • at least one electrode holder can be cooled. This advantageously contributes to the further protection of the electrodes.
  • the bottom of the vessel is cooled at least in one area.
  • a scull crust advantageously forms on the floor area as well, which prevents the corrosion of the floor or the entry of soil material into the material to be melted.
  • Electrodes near the surface of the material to be melted will support these processes at this stage.
  • the cooling can according to the invention by passing a cooling fluid, in particular air and / or water, by at least one electrode and / or at least one electrode holder and / or at least a part of the vessel wall and / or the bottom in a particularly simple manner.
  • a cooling fluid in particular air and / or water
  • the process can advantageously be carried out at particularly high average melt temperatures.
  • the temperature of the melt is heated in at least one range to at least 1700 C, preferably at least about 1800 0 C, more preferably at least about 2000 0 C. Because at the high temperatures that can be realized with the invention and the associated optimum flow of the material to be melted by the device, the removal of bubbles and / or other undesirable substances is promoted, it is advantageously possible to significantly lower amounts of refining agents to use.
  • such high values of temperature are advantageous because, in addition to increasing the transport rates of the substances to be removed in the melt, they reduce the viscosity, which facilitates the escape of the substances to be removed.
  • a particularly suitable design of the flow profile in the vessel and a correspondingly efficient energy utilization can be achieved by setting the temperature difference between the melt in an edge region of the vessel and the melt in the central region of the vessel to more than about 150 K, preferably more than about 250 K. becomes.
  • the edge region extends according to experience over a zone of only a few millimeters.
  • the vessel can be operated in the manner described above according to the invention as part of a continuously operated melting plant. In this case, it is also advantageously possible for the vessel to be continuously fed and discharged to be melted.
  • the material to be melted can advantageously be supplied from a melting tank to the vessel and be removed from the vessel essentially in molten form.
  • a direct coupling of the inventive method as a step of the treatment process of the material to be melted from the raw material to the final product is possible.
  • a main flow direction of the melt is defined.
  • the electromagnetic energy can be coupled in particularly efficiently for heating the melt when the heating current flows between the electrodes substantially along this main flow direction or perpendicular thereto.
  • the melt flows into the vessel in a defined manner.
  • the glass "plunges" cleanly into the vessel, thus reducing the risk of overflow compared to a driving mode in which the heating current flows along the main direction of flow of the melt, ie a so-called longitudinal heating is carried out
  • the transverse heating is in principle also applicable.
  • the invention advantageously offers further possibilities.
  • all electrodes can be supplied with current of the same current intensity.
  • at least one pair of electrodes can also be supplied with current of a magnitude which differs from the value of
  • the electrodes can be connected in such a way that crossover heating currents, in particular according to a Scott circuit, are generated with a phase shift.
  • the melt can be introduced through a channel with a free surface in the vessel and removed from the vessel.
  • An implementation of the method with as few intermediate steps to guide the melt is advantageously possible because the melt is fed to the vessel through an inlet and outlet in the region of the melt surface and discharged from the vessel.
  • the drainage area of the vessel is at least partially cooled.
  • An optimized implementation of the method with regard to time expenditure and efficiency of energy utilization is furthermore made possible by controlling and / or controlling the residence time distribution and / or the average residence time of the melt in the vessel and / or is set.
  • the flow profile and / or the average flow velocity of the melt in the vessel can be regulated and / or controlled and / or adjusted.
  • the volume of the vessel may be dimensioned so that the melt in the vessel has a mean
  • Dwell time of at least about 10 minutes to a period of about 2 hours.
  • a reference point for a corresponding dimensioning of the vessel is to be seen in that the vessel is provided with a volume which is smaller by at least a factor of 1.0 than the volume of a melting tank upstream of the vessel.
  • the height of the melt in the outlet vessel regulated and / or controlled and / or adjusted so that on the ascent rate of the smallest bubbles at the existing middle one
  • the invention makes the electrodes active
  • the invention can be used for the refining of aluminosilicate glass, in particular display glass and lamp glass, and for the refining of borosilicate glass, in particular in the application for pharmaceutical packaging.
  • the process according to the invention can preferably be carried out in such a way that a melt having an electrical conductivity at the melting temperature is in a range from greater than or equal to 10 -3 to less than or equal to 10 2 ⁇ -1 * cm -1 , preferably greater than or equal to 10 "2 to less than or equal to 10 1 ⁇ " 1 * cm '1.
  • conductivity in this preferred range, the coupling of the electromagnetic energy with the aid of the invention is particularly efficient.
  • the inventive method can be used for different melts.
  • the invention offers the possibility of providing at least one grounding device for removing interference currents.
  • the entire arrangement can be provided with at least one, preferably at least two grounding devices in order to provide an additional earth loop in the type of a melting unit
  • the invention provides for providing the arrangement with at least one auxiliary earthing device.
  • a grounding electrode can be used as an auxiliary grounding device, which in particular is connected between the counterelectrode and a metallic component of the arrangement.
  • platinum components such as gutters or stirrers are suitable.
  • the auxiliary earthing device can advantageously be arranged in an overflow and / or a floor drain of the arrangement. If the auxiliary earthing device is grounded directly, a disturbing current becomes low-ohmic Components, in particular on components with platinum, passing away.
  • a grounding device and / or an auxiliary grounding device comprising a series connection of a DC resistor and an AC resistor.
  • a starting operation is carried out in which at least one melting path with sufficient electrical conductivity between the
  • Electrodes are provided for coupling the electromagnetic energy into the melt.
  • the electrodes and / or parts of the wall can be heated during the starting process with a heater so far that their temperature is above the dew point of the upper furnace atmosphere. An entry of substances from the upper furnace atmosphere into the melt can thus be largely avoided.
  • the heating electrodes can be electrochemically passivated before starting and, in particular, converted into a glazed state within the scope of the invention.
  • the counterelectrodes can be electrochemically passivated before starting and in particular converted into a glazed state.
  • An electrode is considered effectively vitrified when the free, "freshly passivated" electrode surface is surrounded by a dense, compact glass layer such that the Even after pulling out of the melt electrode surface is protected from direct contact with corrosive, especially oxygen-containing gases.
  • Such pre-passivated electrodes can then be used elsewhere, especially in cases where the
  • the inventive methods can be operated automatically.
  • One possibility for this is that the regulation and / or control of the heating power of the electrodes by regulation and / or control and / or adjustment of the current flowing through the electrodes takes place.
  • Another possibility is that the regulation and / or control of the heating power of the electrodes by regulation and / or control and / or adjustment of the applied electrical power.
  • the choice between both possibilities can be made according to the properties of the melting material.
  • the electrical conductivity increases with increasing temperature. If the applied power is kept constant, the current consumption through the electrodes increases with decreasing electrical resistance, ie increasing conductivity. This is the risk of damage to the
  • a device for influencing the temperature of a melt which has an arrangement defining at least one space for receiving a melt, in particular a melting and / or refining unit for receiving melted material, at least two heating electrodes for ohmic resistance heating of a melt in the room to
  • the wall of the device may include on its inside during operation of the device a Skullkruste to the advantages described above in terms of Temperature distribution in the vessel to achieve the corrosion protection of the wall material and the almost completely prevented entry of wall material in the melt.
  • the term "inner side” here means the side of the wall facing the melt, that is, toward the interior.
  • the electrodes may have different geometries and shapes.
  • the heating electrodes and / or the counter electrode may comprise plate and / or button and / or ball and / or rod and / or Rogowski and / or T and / or hammer and / or railing electrodes.
  • the shape and geometry of the electrode thereby influence the efficiency of the energy input into the material to be melted.
  • Electrodes in particular in the bottom of the vessel, have been found to be stick electrodes, which may be embodied as solid material and / or as cap electrodes. Electrodes with a specifically enlarged surface, such as, for example, as plate electrodes or in the form of a hammer, offer the advantage of being able to reduce the stress on the electrode surface due to excessively high current densities. This can further contribute to a corresponding design of the form, in which sharp transitions, in particular edges are avoided.
  • rounded outer boundaries of the electrodes have proven. By rounding the edges, the values can be lowered in current density peaks, which in particular a reduction of bladder formation by a factor of 10 can be achieved.
  • the arrangement of the electrodes in particular the distance of the center of the electrode from the next adjacent wall, can be selected as a function of the conductivity of the melt.
  • the use of stick electrodes creates a possibility of the sidewalls of the vessel completely in Skull to keep, which increases the cooling surface of the side walls and thus the cooling effect on the melt, which also convection can be supported.
  • the arrangement of the electrodes according to the invention also has the advantage that no cooled components connected to the cooled crucible walls protrude into the upper furnace space.
  • the electrodes may comprise a fused contact material comprising metals such as osmium, hafnium, molybdenum, tungsten, iridium, tantalum, platinum, platinum metals and / or their alloys. Iridium is of particular importance as the active electrode material.
  • active element refers to the multiple function that the electrode exerts
  • Heating is achieved via the electrode and the flow of the melt by forming a kind of drive for the convection flow in the vessel.
  • the electrodes are in addition to the water-cooled Skull, which causes a downward flow of the melt in the vessel, a part of the so-called convection motor. Due to the heat source, also called thermal spring, around the electrode, an upward flow of the melt forms in the vessel.
  • the electrode thus has, on the one hand, the function of heating and, on the other hand, that of a convection motor and is therefore referred to as an "active" element.
  • the electrode may comprise a core, preferably a ceramic core.
  • at least one electrode is provided with a layer which comprises in particular osmium, hafnium, molybdenum, tungsten, iridium, tantalum, platinum, platinum metals and / or their alloys. Also coatings with any other suitable material are possible according to the invention for use in the device.
  • At least one electrode is exchangeably attached to the device.
  • an electrode In order to reduce the temperature load of the electrodes and thus to be able to realize particularly high melting temperatures, at least one electrode can be cooled.
  • an electrode may include at least one channel for passing a fluid.
  • the bottom of the vessel may, for example, comprise a melt-cast refractory material such as zirconium silicate, which still ensures a much higher resistance than the melt at the high operating temperatures.
  • a melt-cast refractory material such as zirconium silicate
  • the vessel of the device according to the invention may in a preferred embodiment have a cooled bottom and cooled side walls, of which two opposite side walls form the inlet and the drain.
  • the vessel can be designed as a skull crucible.
  • the skull walls can be designed such that they are angled in the installed state below the melt surface at an angle to the outside, whereby a collar is formed. Such a collar is particularly easy to produce when the angle for all skull walls is about 90 °.
  • the side walls are then angled so L-shaped.
  • the device comprises a device for generating alternating current, preferably with an alternating current frequency in a frequency range greater than or equal to 1 kHz to less than or equal to 100 kHz, more preferably with an AC frequency of
  • the device comprises a device for generating direct current, preferably for applying a potential between the at least one heating electrode and the counter electrode with an amount in the range of greater than or equal to 100 mV to less than or equal to 500 mV, preferably of 300 mV.
  • the device comprises at least one inlet area and / or at least one outlet area and / or at least one overflow area. At least one
  • Part of the overflow region and / or the drainage region can be designed as a counter electrode for applying the DC voltage. Furthermore, the invention provides that the arrangement has a Strömungsstotzone in which the counter electrode is positioned.
  • At least part of the overflow area and / or the discharge area is designed as a cooling section.
  • heating electrodes and / or a counterelectrode can be used which have an original state in which they, in particular before starting the device , electrochemically passivated and in particular comprise a glass coating.
  • the arrangement with at least one, in particular with at least two
  • the arrangement may comprise at least one auxiliary earthing device.
  • the auxiliary earthing device has a grounding electrode, which in particular lies between the counterelectrode and a metallic component of the arrangement is connected.
  • the auxiliary grounding device can be arranged, for example, in an overflow and / or a bottom drain of the arrangement.
  • the auxiliary earthing device is grounded directly.
  • the grounding device and / or the auxiliary grounding device can be provided in particular in the form of a series connection of a DC resistance and an AC resistance.
  • Earthing device and / or the auxiliary earthing device may comprise an electrode which has platinum and / or molybdenum and / or tungsten.
  • they are selected such that they are chemically substantially resistant to the material to be melted and its melt. This is equally true for electrodes and / or the walls of the vessel. As material for the vessel, therefore, for example iridium, rhodium or molybdenum come into question.
  • the device according to the invention has a vessel with a geometry which allows the lowest possible ratio between surface area and volume
  • the vessel may have a polygonal, in particular rectangular, in particular square or round, in particular oval, in particular circular ground plan.
  • the device according to the invention can be used in particular as part of a larger system. Is in such a system provides a certain amount of melt, of which only a part is to be further processed in such a way that the advantages associated with the invention can be realized, the invention further provides that a
  • Stream splitting device for dividing a melt flow into at least two partial streams, so that at least one device according to the invention can be arranged in one of the partial streams, and the other partial stream is further processed in another way.
  • the device can be used as a refining and / or cleaning and / or melting module, which can be connected upstream of a following unit, in particular a homogenizing unit and / or a shaping unit.
  • the device according to the invention can be used as a refining and / or cleaning and / or melting module and / or homogenization module, which may be upstream of an Overflow downdraw unit.
  • the present invention enables the production of a highly homogeneous melt, which is particularly suitable as a starting material for the production of, for example, display glasses in an OverfIow downdraw method.
  • the invention can furthermore be used as a refining and / or cleaning module, which is installed in a melting tank, that is, in a vessel through which melt flows.
  • the melting tank can be designed, for example, in a region to form a lautering and / or cleaning module.
  • This wall may, for example, have cooled walls which Include molybdenum.
  • the device according to the invention can be integrated.
  • the device may be connected in the region of its side walls with the walls which form the wall.
  • the level of the melting tank in the flow direction seen before or behind the wall can be significantly greater than the level in the field of lautering and / or cleaning module. This can be achieved by virtue of the module being "hooked" into the wall, so to speak, and the height from the floor of the module to its upper limit being significantly less than the distance from the bottom of the melting tank to the upper boundary of the wall.
  • the path which bubbles have to travel from the melt to leave the latter in the refining and / or cleaning module is small compared to the corresponding path in the melting tank, the refining effect is markedly improved.
  • the invention further provides a product, in particular a glass product, which has been melted and / or purified and / or purified and / or produced according to the inventive method and / or in the device according to the invention.
  • Such products can be characterized, for example, by the value for • the ratio of the amount of Sn 4+ to the amount of Sn 2+ . At higher temperatures, the ratio is shifted towards Sn 2+ .
  • the value for the ratio of the amount of Sn 4+ to the amount of Sn 2+ shifted so that at least 4% to at least 40% more Sn 2+ are present in the mixture.
  • the product has a content of tin of less than 0.4 wt .-%, preferably less than 0.2 wt .-% and particularly preferably less than 0.1 wt .-% to.
  • Cleaning effect due to the invention can still be ensured.
  • water, sulfur and halogens are removed from the melt during the refining or cleaning process.
  • Parameters that characterize inferior raw materials may be a particularly high water content, a particularly high sulfur content, a particularly high content of volatile components such as chloride.
  • a particularly high sulfur content a particularly high content of volatile components such as chloride.
  • Fe contributes to the refining and the ratio of the amounts of Fe 3+ to Fe 2+ is shifted towards Fe 2+ .
  • the product in particular the glass product according to the invention, may comprise at least one glass and / or at least one glass ceramic and / or at least one ceramic which has a low electrical conductivity.
  • the product may comprise aluminosilicate glass, in particular display glass or lamp glass.
  • the product can in particular borosilicate glass, in particular in an application for pharmaceutical packaging.
  • the invention further relates to aggressive glasses such as zinc silicate or
  • Lead silicate glasses can also be handled by means of the invention.
  • the product comprises entrapped bubbles having a volume fraction of less than about 1 ⁇ 10 -8 m 3 , preferably less than about 5 ⁇ 10 -9 m 3, and more preferably less than about 10 -9 m 3 per m 3 of the product.
  • the product therefore has a proportion of iridium of less than 1 ⁇ 10 -6 % by weight, preferably of less than 1 ⁇ 10 -7 % by weight, and more preferably of less than 1 ⁇ 10 -8 % by weight.
  • the proportion of bubbles and the iridium content of the glass in this case represent essential parameters of the glass which has been melted and / or purified and / or purified and / or produced according to the invention.
  • the product therefore has a content of tin of less than 0.4% by weight, preferably less than 0.2% by weight, and more preferably less than 0.1% by weight.
  • the invention also allows the production of glasses with a lower content of nodes. Knots are areas from which substances such as sodium and / or boron evaporate and thus other strength properties are brought about. Through such nodes, in particular problems arise during tube drawing. The invention therefore makes it possible in particular to produce tubes, but also other glasses which have substantially no nodes.
  • FIG. 2 is a schematic representation of the device according to the invention in cross-section, in a sectional plane perpendicular to the flow direction of the melt through the vessel with Skullkruste,
  • FIG. 3 shows a schematic representation of the device according to the invention in cross section in a sectional plane perpendicular to the direction of flow of the melt through the vessel in the filled state
  • Fig. 4 is a schematic representation of the device according to the invention in cross section in a sectional plane parallel to
  • FIG. 6 is a schematic representation of the device according to the invention in cross section in a sectional plane parallel to the flow direction of the melt according to a further embodiment with additional heating and the flow of the melt influencing internals,
  • FIG. 7 is a schematic representation of the device according to the invention in cross-section in a sectional plane perpendicular to the direction of flow of the melt through the vessel to illustrate the cooling of the vessel bottom,
  • Fig. 8 are schematic representations of the invention
  • FIG. 9 are schematic representations of the invention
  • FIG. 10 are schematic representations of the device according to the invention in plan view.
  • FIG. 1 shows an exemplary selection of such electrodes 4.
  • Rod electrodes can have a round (FIG. 1A) section and can also be used connected together as railing electrodes (FIG. 1C).
  • Plate electrodes (FIG. 1B) can also be used in Their geometry can be varied as well as connected in series ( Figure ID). The connection of the individual electrodes leads to one another in a particularly advantageous manner to a much higher. Stability of the electrode arrangements.
  • the use of T-electrodes (FIG. IE) can also be advantageous.
  • a scull crust forms.
  • An arrangement of the device with this Skullkruste 14 is shown in Figure 2.
  • a scull crust forms inside the vessel wall 10, namely a layer of solidified melt 14, because the vessel wall 10 is so strongly cooled that the melt material from the interior of the vessel on the wall 10 stiffens.
  • a cooling of the vessel wall can be done by passing coolant through the tubes of Skulltiegels.
  • the device 1 has corresponding sockets for the coolant inlet 121 or the coolant outlet 122.
  • the melt 16 is not in contact with the vessel wall 10 of the skull crucible during operation of the device 1 according to the invention, because in between the solidified melt 14 is formed as a scull crust.
  • the device 1 In order to be able to reduce or avoid a cooling of the melt 16 at the molten bath surface 18, it may be expedient to operate the device 1 with an additional heating. According to the in Fig.
  • FIG. 4 shows in detail the convection roller 28 which then adjusts.
  • the melt enters via the inlet 20 into the vessel 2. Due to the cooling of the wall of Skulltiegels 10 the melt solidifies in the form of
  • FIG. 6 shows another embodiment of the device 1, which here is operated with additional heating in the upper furnace space 26 via gas burners 24, which are arranged in a support frame 25, wherein the support frame 25 also serves as a suspension for flow-influencing internals 30, from above into the melt be dipped.
  • flow-influencing internals 30 may also be provided on the side walls 10 of the vessel 2.
  • the flow-influencing internals 30 can be arranged in the interior of the vessel 2.
  • FIG. 7 is in the simplified representation of the device 1, the cooling of the vessel bottom by on the
  • Bottom plate 8 resting tubes 81 shown.
  • the scull crust 14 is formed around the tubes 81 in a manner similar to that which can grow into the interior of the vessel such that the cooling tubes 81 on the vessel bottom are enclosed by the scull crust 14.
  • FIGS. 8, 9 and 10 A plan view of the vessel with counterelectrodes arranged at various locations is shown in FIGS. 8, 9 and 10.
  • FIG. 8 shows electrodes 4 which are arranged next to one another in two rows. The rows are arranged parallel to the flow direction of the melt directed from the inlet 20 through the vessel 2 to the outlet 22. Inlet and outlet of the side walls 10 of the vessel 2 are designed angled so that the bent part is directed away from the vessel 2 and thus forms a collar 6. Following the collar, the environment 7 of the device in FIG. 8 is shown for orientation.
  • the counter electrode 5 is arranged in Figure 8 in the middle of the drain 22.
  • FIG. 9 shows an embodiment in which the counter-electrode 5 is positioned at the inlet 20 of the vessel 2. Another particular embodiment is shown in FIG. In this embodiment, the edge between vessel 2 and drain 22 is designed as a planar counterelectrode.
  • the invention allows the melting and / or refining and / or cleaning difficult to be treated Glasses such as the display glass AF37.
  • the use of auxiliary electrodes and the application of direct current between the counter electrodes and the heating electrodes result in substantially increased electrode service life and less bubble inclusions.
  • the device can be operated in particular such that the mean residence time is at least 10 minutes. This results in corresponding ratios of the values for the volume of the vessel and the throughput. Decisive here are in particular the glass-type dependent viscosity and the volume expansion coefficient.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Glass Melting And Manufacturing (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Furnace Details (AREA)

Abstract

L’invention concerne un procédé et un dispositif de protection contre la corrosion d'électrodes et de diminution des bulles de gaz dans une fonte. Cela est réalisé selon l’invention en appliquant un courant continu entre au moins deux électrodes de chauffage et au moins une contre-électrode dans une unité de fusion de verre ou de purification.
EP07702929A 2006-01-24 2007-01-22 Procédé et dispositif de protection contre la corrosion d'électrodes par l'influence de la température d'une fonte Withdrawn EP1991506A1 (fr)

Applications Claiming Priority (2)

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DE102006003534A DE102006003534A1 (de) 2006-01-24 2006-01-24 Verfahren und Vorrichtung zum Korrosionsschutz von Elektroden bei der Temperaturbeeinflussung einer Schmelze
PCT/EP2007/000508 WO2007085397A1 (fr) 2006-01-24 2007-01-22 Procédé et dispositif de protection contre la corrosion d’électrodes par l'influence de la température d'une fonte

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DE102009002336B4 (de) 2009-04-09 2012-09-20 Schott Ag Verfahren und Vorrichtung zum Läutern einer Glasschmelze
DE102010037376A1 (de) * 2009-09-15 2011-04-07 Schott Ag Verfahren und Vorrichtungen zur Vermeidung von Glasblasenbildung bei der Glasherstellung
DE102010036627B4 (de) 2010-07-26 2013-01-17 Schott Ag Verfahren und Vorrichtung zum Korrosionsschutz von Elektroden bei der Temperaturbeeinflussung einer Glasschmelze
WO2013084832A1 (fr) 2011-12-06 2013-06-13 旭硝子株式会社 Procédé de fabrication de verre non alcalin
CN104136383B (zh) 2012-02-27 2016-09-28 旭硝子株式会社 无碱玻璃的制造方法
JP2016188147A (ja) 2013-08-26 2016-11-04 旭硝子株式会社 無アルカリガラスの製造方法
DE102016107577A1 (de) 2016-04-25 2017-10-26 Schott Ag Vorrichtung und Verfahren zur Herstellung von Glasprodukten aus einer Glasschmelze unter Vermeidung von Blasenbildung
US11028001B2 (en) * 2016-11-08 2021-06-08 Corning Incorporated High temperature glass melting vessel
DE102018108418A1 (de) * 2018-04-10 2019-10-10 Schott Ag Verfahren zur Herstellung von Glasprodukten sowie hierzu geeignete Vorrichtung
KR102581636B1 (ko) * 2019-01-04 2023-09-22 주식회사 엘지화학 유리 청징 장치
DE102019217977A1 (de) * 2019-11-21 2021-05-27 Schott Ag Glas, Verfahren zur Herstellung eines Glases und Glasschmelzanlage
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EP4342856A1 (fr) * 2022-09-21 2024-03-27 Schott Ag Procédé et appareil de fabrication d'un produit en verre et produit en verre correspondant

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