CA1258588A - Method for producing glass bubbles - Google Patents
Method for producing glass bubblesInfo
- Publication number
- CA1258588A CA1258588A CA000484292A CA484292A CA1258588A CA 1258588 A CA1258588 A CA 1258588A CA 000484292 A CA000484292 A CA 000484292A CA 484292 A CA484292 A CA 484292A CA 1258588 A CA1258588 A CA 1258588A
- Authority
- CA
- Canada
- Prior art keywords
- glass
- atmosphere
- steam
- heating
- glass powder
- 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.)
- Expired
Links
- 239000011521 glass Substances 0.000 title claims abstract description 70
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 9
- 239000012298 atmosphere Substances 0.000 claims abstract description 35
- 238000010438 heat treatment Methods 0.000 claims abstract description 33
- 239000000843 powder Substances 0.000 claims abstract description 29
- 239000004604 Blowing Agent Substances 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 claims description 21
- 239000000446 fuel Substances 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 239000006260 foam Substances 0.000 abstract description 3
- 239000000463 material Substances 0.000 description 11
- 238000007664 blowing Methods 0.000 description 9
- QXJJQWWVWRCVQT-UHFFFAOYSA-K calcium;sodium;phosphate Chemical compound [Na+].[Ca+2].[O-]P([O-])([O-])=O QXJJQWWVWRCVQT-UHFFFAOYSA-K 0.000 description 9
- 239000007789 gas Substances 0.000 description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 239000000306 component Substances 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000005187 foaming Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 2
- 229910001634 calcium fluoride Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000005357 flat glass Substances 0.000 description 2
- 238000007496 glass forming Methods 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 238000003303 reheating Methods 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 235000017550 sodium carbonate Nutrition 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 1
- 239000007832 Na2SO4 Substances 0.000 description 1
- 208000036366 Sensation of pressure Diseases 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910000272 alkali metal oxide Inorganic materials 0.000 description 1
- 239000005388 borosilicate glass Substances 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 235000010216 calcium carbonate Nutrition 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
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
- C03B19/108—Forming porous, sintered or foamed beads
- C03B19/1085—Forming porous, sintered or foamed beads by blowing, pressing, centrifuging, rolling or dripping
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
Abstract
Abstract of the Disclosure:
A method for producing glass bubbles, which comprises heating a glass powder containing a gas-blowing agent in an atmosphere containing steam having a partial steam pressure of at least 0.2 atmosphere to foam it.
A method for producing glass bubbles, which comprises heating a glass powder containing a gas-blowing agent in an atmosphere containing steam having a partial steam pressure of at least 0.2 atmosphere to foam it.
Description
~2~8~
This invention relates to an improved method for the production of glass bubbles, and more specifically, to a method for producing in high yields minute hollow glass spheres which are useful as additives to plastic articles or slurry explosives.
Generally~ minute hollow glass spheres are pro-duced by a method comprising blowing a powder of sheet glass or bottle glass scraps or a powder of volcanoic glass into a flame to heat-soften the glass in a floating and fluidized state, and gasifying a blowing material such as SO3, H2O, F and CO2 dissolved in the glass powder or arti-ficially dissolved in it, as described, for example, in U. S. Patent No. 3,365,315.
According to the above method, foaming of the 1~ glass powder is dependent upon the temperature of the heating atmosphere and the residence time. But since the temperature of the flame and the flow rate of the gas are not uniform, a difference in the degree of foaming arises among the individual glass particles, and the yield of hollow glass spheres having the desired specific gravity is low. To make the heating conditions for the glass powder uniform, a method may be feasible which involves allowing the glass powder to fall into an electrical furnace. This method however gives rise to another problem in that the efficiency of heat conduction is low owing to heating by irradiation and a very long electrical furnace is required in order to heat the glass powder to a temperature at which 1;~5858~3 it fully foams, thereby leading to high costs of the apparatus and energy required~
In view o~ the state of the art described above, the present inventors made extensive investigations in order to provide a method for producing minute glass bubbles in an increased yield by reheating a glass powder containing a gas-blowing material. These investigations have led to the surprising discovery that the yield of glass bubbles is markedly increased if steam is present in a heating atmosphere for the glass powder in such a proportion as to ad~ust the partial pressure of æteam to at least 0.2 atmosphere.
Thus, according to this invention, there is provided a method for producing glass bubbles, whlch comprises heating a glass powder containing a gas-blowing agent in an atmosphere containing steam having a partial steam pressure of 0.2 to 0.5 atmosphere at a temperature of about 1000 to 1600C to expand it.
Fre~uently, anhydrous sodium sulfate, calcium carhonate, sodium carbonate, calcium fluoride, etc. are added durlng the production of sheet glass or bottle glass. When the glass-forming components are melted by heatlng, these additive components are decomposed to release S03, C02, F2, etc. Most of these gases dissipate into the atmosphere, but partly remain ln the dissolved state in the glass. For example, S03 dissolved in the glass decomposed on reheating the glass (S03 ~ S02 + 2) to form bubbles.
~ ~8~:~88 This phenomenon has long been known as the ~reboil phenom-enonn. The formation of glass bubbles takes advantage of the reboil phenomenon by heating the glass powder and is carried out by heating a glass powder containing such gas-blowing materials as mentioned above. The reboil phenomenon has been commonly used in the production of glass bubbles.
The method of the present invention can be carried out basically by the conventional technique of producing glass bubbles except that a heating atmopshere containing steam having a partial pressure of at least 0.2 atmosphere is used. Such a technique of producing glass bubbles is disclosed, for example, in U. S. Patent 3,365,315, and the disclosure of this U. S. Patent is cited herein in lieu of giving a detailed description thereof.
A glass powder containing a gas-blowing material can be prepared, for example, by adding a precursor such as Na2SO4, Na2CO3, CaCO3 or CaF2 of a gas-blowing material such as SO3, CO2, H2O and F2 as one of glass forming com-ponents at the time of producing glass, or by impregnating the glass powder with SO3, CO2, H2O, etc. under high pres-sure in an autoclave. Advantageously, the glass powder used in this invention has a particle diameter of generally 5 to 200 microns, preferably lO to lO0 microns.
2S According to this invention, the glass material containing the gas-blowing material is heated in an atmos-B phere containing steam having a partial steam pressure of a~ lc~st 0.2 atmosphere.
1;~5~58 In the present specification and the appended claims, the partial pressure of steam in the atmosphere is the partial pressure of steam when the total pressure of the atmosphere is assumed to be 1 atmosphere. In the present application, it can be measured in accordance with the method described in JIS Z8808-1977, Method of Measuring Dust Content in Flue Gas, 5. "Measurement of the Water Content of the Waste Gas n .
The following methods, for example, are conveni-ently used in this invention to provide partial steampressures of at least 0.2 atmosphere in the heating atmos-phere for the glass powder.
(A) Steam is blown into a heating chamber or water is sprayed to it. An electrical heating furnace may be used at this time. But to reduce the energy cost, it is preferable to recycle the discharged steam for reuse.
(B) Hydrogen gas is used as a fuel.
(C) A hydrocarbon-type fuel such as methane, ethane, propane, butane, kerosene, heavy oil, methanol or ethanol is used as a fuel. At the same time, oxygen or oxygen-enriched air is used for burning to decrease the partial pressure of nitrogen in the burnt gas.
(D) A combination of two or three of the methods (A), (B) and (C) is used.
When the fuel cost or the cost of oxygen is considered, it is preferred that the method of this inven-tion be industrially carried out by using natural gas as ~ 25~
a fuel, burning it with air, and increasing the partial pressure of steam in the burning gas by feeding water, preferably steam.
If the partial pressure of steam in the heating atmosphere is at least 0.2 atmosphere, the effect of in-creasing the yield of glass bubbles intended by the present invention can be achieved. But when the partial pressure of steam exceeds 0.5 atmosphere, no corresponding increase in the effect of increasing the yield can be expected, and it rather gives rise to a possibility of lowering the temperature of the burning gas. Generally, the suitable partial pressure of steam is within the range of 0.2 to 0.5 atmosphere, particularly 0.23 to 0.4 atmosphere.
It has not been theoretically elucidated why the adjustment of the partial pressure of steam in the heating atmosphere for the glass powder to at least 0.2 atmosphere leads to an increase in the yield of glass bubbles obtained by the foaming of the glass powder. But the following causes may be assumed.
(1) The formation of hollow glass spheres is considered to be effected on the principle that as stated hereinabove, the glass powder is softened by heating, and thereafter SO3 or H2O dissolved in the glass becomes supersaturated as a result of the rise of the glass tem-perature and becomes gasified and expanded (namely, "reboiled"). The reboiling in the glass occurs to a greater extent as the temperature of the glass becomes higher. Even at a constant temperature, changes in the glass composition cause changes in the solubility of SO3 or H2O, and may lead to easier reboiling. The present inven-tors found that when a fine glass powder is heated to a higher temperature in the presence of steam, B2O3 or alkali metal oxides in the glass volatilize in unexpectedly large amounts within very short periods of time to change the glass composition, and that the glass composition changes to a higher degree as the partial pressure of steam in the heating atmosphere is higher.
It is presumed that in the present invention, the presence of a large amount of steam in the atmosphere promotes changing of the glass composition whereby the solubility of SO3 or H2O in the glass is reduced and it is more easily reboiled.
This invention relates to an improved method for the production of glass bubbles, and more specifically, to a method for producing in high yields minute hollow glass spheres which are useful as additives to plastic articles or slurry explosives.
Generally~ minute hollow glass spheres are pro-duced by a method comprising blowing a powder of sheet glass or bottle glass scraps or a powder of volcanoic glass into a flame to heat-soften the glass in a floating and fluidized state, and gasifying a blowing material such as SO3, H2O, F and CO2 dissolved in the glass powder or arti-ficially dissolved in it, as described, for example, in U. S. Patent No. 3,365,315.
According to the above method, foaming of the 1~ glass powder is dependent upon the temperature of the heating atmosphere and the residence time. But since the temperature of the flame and the flow rate of the gas are not uniform, a difference in the degree of foaming arises among the individual glass particles, and the yield of hollow glass spheres having the desired specific gravity is low. To make the heating conditions for the glass powder uniform, a method may be feasible which involves allowing the glass powder to fall into an electrical furnace. This method however gives rise to another problem in that the efficiency of heat conduction is low owing to heating by irradiation and a very long electrical furnace is required in order to heat the glass powder to a temperature at which 1;~5858~3 it fully foams, thereby leading to high costs of the apparatus and energy required~
In view o~ the state of the art described above, the present inventors made extensive investigations in order to provide a method for producing minute glass bubbles in an increased yield by reheating a glass powder containing a gas-blowing material. These investigations have led to the surprising discovery that the yield of glass bubbles is markedly increased if steam is present in a heating atmosphere for the glass powder in such a proportion as to ad~ust the partial pressure of æteam to at least 0.2 atmosphere.
Thus, according to this invention, there is provided a method for producing glass bubbles, whlch comprises heating a glass powder containing a gas-blowing agent in an atmosphere containing steam having a partial steam pressure of 0.2 to 0.5 atmosphere at a temperature of about 1000 to 1600C to expand it.
Fre~uently, anhydrous sodium sulfate, calcium carhonate, sodium carbonate, calcium fluoride, etc. are added durlng the production of sheet glass or bottle glass. When the glass-forming components are melted by heatlng, these additive components are decomposed to release S03, C02, F2, etc. Most of these gases dissipate into the atmosphere, but partly remain ln the dissolved state in the glass. For example, S03 dissolved in the glass decomposed on reheating the glass (S03 ~ S02 + 2) to form bubbles.
~ ~8~:~88 This phenomenon has long been known as the ~reboil phenom-enonn. The formation of glass bubbles takes advantage of the reboil phenomenon by heating the glass powder and is carried out by heating a glass powder containing such gas-blowing materials as mentioned above. The reboil phenomenon has been commonly used in the production of glass bubbles.
The method of the present invention can be carried out basically by the conventional technique of producing glass bubbles except that a heating atmopshere containing steam having a partial pressure of at least 0.2 atmosphere is used. Such a technique of producing glass bubbles is disclosed, for example, in U. S. Patent 3,365,315, and the disclosure of this U. S. Patent is cited herein in lieu of giving a detailed description thereof.
A glass powder containing a gas-blowing material can be prepared, for example, by adding a precursor such as Na2SO4, Na2CO3, CaCO3 or CaF2 of a gas-blowing material such as SO3, CO2, H2O and F2 as one of glass forming com-ponents at the time of producing glass, or by impregnating the glass powder with SO3, CO2, H2O, etc. under high pres-sure in an autoclave. Advantageously, the glass powder used in this invention has a particle diameter of generally 5 to 200 microns, preferably lO to lO0 microns.
2S According to this invention, the glass material containing the gas-blowing material is heated in an atmos-B phere containing steam having a partial steam pressure of a~ lc~st 0.2 atmosphere.
1;~5~58 In the present specification and the appended claims, the partial pressure of steam in the atmosphere is the partial pressure of steam when the total pressure of the atmosphere is assumed to be 1 atmosphere. In the present application, it can be measured in accordance with the method described in JIS Z8808-1977, Method of Measuring Dust Content in Flue Gas, 5. "Measurement of the Water Content of the Waste Gas n .
The following methods, for example, are conveni-ently used in this invention to provide partial steampressures of at least 0.2 atmosphere in the heating atmos-phere for the glass powder.
(A) Steam is blown into a heating chamber or water is sprayed to it. An electrical heating furnace may be used at this time. But to reduce the energy cost, it is preferable to recycle the discharged steam for reuse.
(B) Hydrogen gas is used as a fuel.
(C) A hydrocarbon-type fuel such as methane, ethane, propane, butane, kerosene, heavy oil, methanol or ethanol is used as a fuel. At the same time, oxygen or oxygen-enriched air is used for burning to decrease the partial pressure of nitrogen in the burnt gas.
(D) A combination of two or three of the methods (A), (B) and (C) is used.
When the fuel cost or the cost of oxygen is considered, it is preferred that the method of this inven-tion be industrially carried out by using natural gas as ~ 25~
a fuel, burning it with air, and increasing the partial pressure of steam in the burning gas by feeding water, preferably steam.
If the partial pressure of steam in the heating atmosphere is at least 0.2 atmosphere, the effect of in-creasing the yield of glass bubbles intended by the present invention can be achieved. But when the partial pressure of steam exceeds 0.5 atmosphere, no corresponding increase in the effect of increasing the yield can be expected, and it rather gives rise to a possibility of lowering the temperature of the burning gas. Generally, the suitable partial pressure of steam is within the range of 0.2 to 0.5 atmosphere, particularly 0.23 to 0.4 atmosphere.
It has not been theoretically elucidated why the adjustment of the partial pressure of steam in the heating atmosphere for the glass powder to at least 0.2 atmosphere leads to an increase in the yield of glass bubbles obtained by the foaming of the glass powder. But the following causes may be assumed.
(1) The formation of hollow glass spheres is considered to be effected on the principle that as stated hereinabove, the glass powder is softened by heating, and thereafter SO3 or H2O dissolved in the glass becomes supersaturated as a result of the rise of the glass tem-perature and becomes gasified and expanded (namely, "reboiled"). The reboiling in the glass occurs to a greater extent as the temperature of the glass becomes higher. Even at a constant temperature, changes in the glass composition cause changes in the solubility of SO3 or H2O, and may lead to easier reboiling. The present inven-tors found that when a fine glass powder is heated to a higher temperature in the presence of steam, B2O3 or alkali metal oxides in the glass volatilize in unexpectedly large amounts within very short periods of time to change the glass composition, and that the glass composition changes to a higher degree as the partial pressure of steam in the heating atmosphere is higher.
It is presumed that in the present invention, the presence of a large amount of steam in the atmosphere promotes changing of the glass composition whereby the solubility of SO3 or H2O in the glass is reduced and it is more easily reboiled.
(2) It is presumed on the other hand that when glass makes contact with steam at high temperatures, hydr-ated glass will form. Since glass usually has a lowered softening temperature on hydration, the hydrated glass is less viscous at high temperatures and has increased foam-ability.
It is also known, although no reason can be assigned, that the reboiling of gas components in the glass is sensitive to the heating atmosphere. The present inven-2S tors have found that the yield of glass bubbles can befurther increased by providing a reducing atmopshere as the heating atmosphere in addition to increasing the partial 1;~5~588 pressure of steam in the heating atmosphere.
The reducing atmosphere can easily be formed, for example, by decreasing the ratio of oxygen to a fuel fed to a heating chamber below the stoichiometrial value, and incompletely burning the fuel in the heating chamber.
One typical procedure for carrying out the method of this invention comprises feeding a glass powder contain-ing a gas-blowing material, a fuel, an oxygen-containing gas (such as air) required for the burning of the fuel, and water to a heating chamber, for example a vertical furnace constructed of a refractory or a water-cooled metal, and burning the fuel to thereby heat and foam the glass powder.
In this procedure, the total partial pressure of steam derived from water supplied and steam that may be generated by the burning should be adjusted to at least 0.2 atmos-phere.
Preferably, the water is supplied in the form of vapor to the heating chamber simultaneously with the sup-plying of the glass powder.
The temperature in the heating chamber may generally be about 1,000 to about 1,600, preferably about 1300 to about 1500C, and the sufficient residence time is about 0.1 to about 3 seconds.
The method of this invention described above can give glass bubbles in a yield at least about 1.5 times as high as that in the prior art, and contributes greatly to the industry.
~ ~ 85 The following Example illustrates the present invention more specifically.
EXAMPLE
~ igure 1 shows a rough sketch showing one example of an apparatus for producing hollow glass spheres in accordance with this invention. A powdery glass material is fed to a hopper (5) in a fixed quantity by a suitable feed device (not shown) such as a screw feeder or a vibratory feeder. The bottom portion of the hopper (5) is connected to an ejector (6) having a nozzle therein, and compressed air is supplied to the nozzle from a compressor (llJ or the like. The glass material which falls from the hopper (~ is dispersed by an air current jetted from the nozzle of the ejector (6) and blown in the dispersed state into a heating furnace (1) through a batch blowing opening (10) at the bottom of the furnace (1). The heating furnace (1) is of a vertical type and constructed of a refractory material~ A burner (4) and a steam feed opening (7) are provided at the bottom portion of the heating furance (1).
A gaseous or liquid fuel and air are supplied to the burner (4) and burned in the heating furnace (1). Steam generated by a boiler (12) or the like is fed into the heating furnace (1) through the steam feed opening 17) while con-trolling its flow rate by a needle valve or the like.
The glass material is dispersed in a flame mixed with steam, heated, and rise together with the burning gas through the furnace while forming hollow glass spheres.
~X5~5~3~
g The glass spheres or bubbles are finally collected by a cyclone (2) via a hood (8) and a duct ~9). A very small amount of the glass bubbles which are not collected by the cyclone (2) are collected by a bag filter (3).
A powder having a particle diameter of less than 100 microns and an average particle diameter of 30 microns of an alkali borosilicate glass having the composition containing, by wt.%, 68.4 SiO2, 10.3 B2O3, 0.94 ZnO, 19.4 Na2O, 0.82 SO3 and the balance 0.14 was used as the start-ing material, and hollow glass spheres (sample Nos. 1 to 6 shown in Table 1) were produced by using the apparatus shown in Fig. 1 under the heating conditions shown in Table 1.
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It is also known, although no reason can be assigned, that the reboiling of gas components in the glass is sensitive to the heating atmosphere. The present inven-2S tors have found that the yield of glass bubbles can befurther increased by providing a reducing atmopshere as the heating atmosphere in addition to increasing the partial 1;~5~588 pressure of steam in the heating atmosphere.
The reducing atmosphere can easily be formed, for example, by decreasing the ratio of oxygen to a fuel fed to a heating chamber below the stoichiometrial value, and incompletely burning the fuel in the heating chamber.
One typical procedure for carrying out the method of this invention comprises feeding a glass powder contain-ing a gas-blowing material, a fuel, an oxygen-containing gas (such as air) required for the burning of the fuel, and water to a heating chamber, for example a vertical furnace constructed of a refractory or a water-cooled metal, and burning the fuel to thereby heat and foam the glass powder.
In this procedure, the total partial pressure of steam derived from water supplied and steam that may be generated by the burning should be adjusted to at least 0.2 atmos-phere.
Preferably, the water is supplied in the form of vapor to the heating chamber simultaneously with the sup-plying of the glass powder.
The temperature in the heating chamber may generally be about 1,000 to about 1,600, preferably about 1300 to about 1500C, and the sufficient residence time is about 0.1 to about 3 seconds.
The method of this invention described above can give glass bubbles in a yield at least about 1.5 times as high as that in the prior art, and contributes greatly to the industry.
~ ~ 85 The following Example illustrates the present invention more specifically.
EXAMPLE
~ igure 1 shows a rough sketch showing one example of an apparatus for producing hollow glass spheres in accordance with this invention. A powdery glass material is fed to a hopper (5) in a fixed quantity by a suitable feed device (not shown) such as a screw feeder or a vibratory feeder. The bottom portion of the hopper (5) is connected to an ejector (6) having a nozzle therein, and compressed air is supplied to the nozzle from a compressor (llJ or the like. The glass material which falls from the hopper (~ is dispersed by an air current jetted from the nozzle of the ejector (6) and blown in the dispersed state into a heating furnace (1) through a batch blowing opening (10) at the bottom of the furnace (1). The heating furnace (1) is of a vertical type and constructed of a refractory material~ A burner (4) and a steam feed opening (7) are provided at the bottom portion of the heating furance (1).
A gaseous or liquid fuel and air are supplied to the burner (4) and burned in the heating furnace (1). Steam generated by a boiler (12) or the like is fed into the heating furnace (1) through the steam feed opening 17) while con-trolling its flow rate by a needle valve or the like.
The glass material is dispersed in a flame mixed with steam, heated, and rise together with the burning gas through the furnace while forming hollow glass spheres.
~X5~5~3~
g The glass spheres or bubbles are finally collected by a cyclone (2) via a hood (8) and a duct ~9). A very small amount of the glass bubbles which are not collected by the cyclone (2) are collected by a bag filter (3).
A powder having a particle diameter of less than 100 microns and an average particle diameter of 30 microns of an alkali borosilicate glass having the composition containing, by wt.%, 68.4 SiO2, 10.3 B2O3, 0.94 ZnO, 19.4 Na2O, 0.82 SO3 and the balance 0.14 was used as the start-ing material, and hollow glass spheres (sample Nos. 1 to 6 shown in Table 1) were produced by using the apparatus shown in Fig. 1 under the heating conditions shown in Table 1.
~2S85~
_ ~ . / ~
~D ~ u~ O ~D ~ In o o ~n o ~ ~
~ U~ 7 ~D ~
~ / \ ~
. . .. . ~
oo U:> ~ ~ ~ ~ U7 ~ ~ ~ ~ a~ r o u~
tn ~o ~ o u~ o o u~ C~ ~ o o u~ o o ~ ~ 1 ~ 1_ a~ ~
.,., ~ cr _ ~ .. ~ aJ
' ~D a~ ~ \ /
I` I` ~ ~ C~
U~ CO ~ o o o o o o ~ ~D / \ ~
_ . .. . . . ~ o _, ~o eP o~ ~ ~ o o~
~00 ~ C'l ~ _l CO ~ ~ ~r ~r o ~1 ~1~ O U~ ~ O O O 00 0 CD r~ O O) O O
~ r ~D CO Q
_ . _ _ , _l ~ ~ ~ a~ r li~ O ~ I t'~ O O ~1 0 If~ .-1 0 _I O ~1 ~
_~ ~ ~ D ~ CO _~ O
a~ o _, n ,~ u~ o u~ ~ .
~ ~ ~ ~ ~ \ / g n o :r I o o o ~ o X
J ~ n ~7 / \ ~
~ ~ / U~
_ _ _ , ~
s 0 ~ ~:: .O,~O~ .C
_ ~ ~ U~ ~ W Z o o7 ~ _ ~ ~ o .
a) ~ _~ .c ~ ~ ~ a) ~J
~ C ~ ,~ 0 J-a~ ~ aJ ~
~ ~ ~_ ' a) ~ 0 ~ ~ ~ O JJ ~3 dP ~ 0~ ~
O o ~0 0 ~ u~ ~ 0 ,~-- ~n o JJ
a) Q~ ~ 0~ ~ ~0-~
C 5 C; C ~ I.C ~ O ~ : ~J
3 ~ _ ~3 . _ , JJ
SUOI~lpuo~ 6ul~e~H sa~ ds sse~6 M11H
1~:5~58?~
-- 11 ~
As is clear from the results of Table 1, the expansion ratio of the hollow glass spheres is increased, and the yield of the product can be markedly increased, by the method of this invention. Furthermore, the amount of the fuel can be reduced without lowering the yield (see sample No. 4). Furthermore, since the maximum temperature within the furnace can be drastically lowered, damages of the apparatus can be reduced.
SUOI~lpuo~ 6ul~e~H sa~ ds sse~6 M11H
1~:5~58?~
-- 11 ~
As is clear from the results of Table 1, the expansion ratio of the hollow glass spheres is increased, and the yield of the product can be markedly increased, by the method of this invention. Furthermore, the amount of the fuel can be reduced without lowering the yield (see sample No. 4). Furthermore, since the maximum temperature within the furnace can be drastically lowered, damages of the apparatus can be reduced.
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for producing glass bubbles, which comprises heating a glass powder containing a gas-blowing agent in an atmosphere containing steam having a partial steam pressure of 0.2 to 0.5 atmosphere at a temperature of about 1000° to 1600°C to expand it.
2. The method of claim 1 wherein the partial pressure of steam in the atmosphere is within the range of 0.23 to 0.4 atmosphere.
3. The method of claim 1 wherein the atmosphere is a reducing atmosphere.
4. The method of claim 1 wherein the glass powder, a fuel, air for burning, and water are fed to a heating chamber, and by burning the fuel, the glass powder is heated and formed.
5. The method of claim 4 wherein the water is steam, and is fed to the heating chamber simultaneously with the supplying of the glass powder.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59127865A JPS616142A (en) | 1984-06-21 | 1984-06-21 | Production of hollow glass sphere |
| JP127,865/84 | 1984-06-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1258588A true CA1258588A (en) | 1989-08-22 |
Family
ID=14970563
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000484292A Expired CA1258588A (en) | 1984-06-21 | 1985-06-18 | Method for producing glass bubbles |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4693739A (en) |
| JP (1) | JPS616142A (en) |
| CA (1) | CA1258588A (en) |
| DE (1) | DE3522291A1 (en) |
| FR (1) | FR2566385B1 (en) |
| GB (1) | GB2162509B (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4801563A (en) * | 1986-09-26 | 1989-01-31 | White Eugene M | Thermal insulating expanded silicate-hydrate product and method of forming |
| RU2059574C1 (en) * | 1992-05-07 | 1996-05-10 | Владимир Викторович Будов | Hollow glass micro spheres production method |
| AU701603B2 (en) * | 1994-04-25 | 1999-02-04 | Minnesota Mining And Manufacturing Company | Compositions comprising fused particulates and methods of making them |
| WO1996007538A1 (en) * | 1994-09-06 | 1996-03-14 | Thermacell Technologies, Inc. | Insulation microspheres and method of manufacture |
| US6045913A (en) * | 1995-11-01 | 2000-04-04 | Minnesota Mining And Manufacturing Company | At least partly fused particulates and methods of making them by flame fusion |
| US6254981B1 (en) | 1995-11-02 | 2001-07-03 | Minnesota Mining & Manufacturing Company | Fused glassy particulates obtained by flame fusion |
| DE10042071C1 (en) * | 2000-08-16 | 2002-03-21 | Mattig & Lindner Gmbh | Porous silicate granulate used as additive for the production of building materials such as light concrete, mortar or heat insulating plaster contains glass and a glassy crystalline component |
| RU2332364C2 (en) * | 2006-01-17 | 2008-08-27 | Дмитрий Андреевич Климов | Method of manufacturing of longlasting foamglass |
| WO2011072600A1 (en) * | 2009-12-18 | 2011-06-23 | 东南大学 | Manufacturing method of wafer level glass microcavity by using foaming molding |
| WO2015200784A2 (en) * | 2014-06-27 | 2015-12-30 | Ams Research Corporation | Implantable penile prostheses |
| CN113072303A (en) * | 2021-03-29 | 2021-07-06 | 浙江奕成科技有限公司 | Shape changing method of glass powder for solar cell conductive silver paste |
Family Cites Families (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2524613A (en) * | 1949-07-09 | 1950-10-03 | Cataphote Corp | Method of manufacturing rounded glass particles |
| NL232500A (en) * | 1957-10-22 | |||
| GB1051334A (en) * | 1962-08-01 | 1900-01-01 | ||
| GB1032608A (en) * | 1963-04-11 | 1966-06-15 | Fred Osborne | Method of and apparatus for processing molten slag and the like |
| US3403990A (en) * | 1964-03-03 | 1968-10-01 | Schaumglaswerk Taubenbach Veb | Process for making foam glass |
| GB1023755A (en) * | 1964-04-13 | 1966-03-23 | Int Rectifier Corp | Lapping device |
| US3699050A (en) * | 1967-08-02 | 1972-10-17 | Emerson & Cuming Inc | Spray dried product for feed in the manufacture of hollow glass spheres and process for forming said spray dried product |
| US3692507A (en) * | 1969-12-29 | 1972-09-19 | Fiberglas Canada Ltd | Production of alkali metal silicate fibers |
| US3870496A (en) * | 1971-08-23 | 1975-03-11 | Univ Utah | Method of creating a foamed glass product from waste glass |
| US4059425A (en) * | 1975-01-20 | 1977-11-22 | Corning Glass Works | Gaseous process for hydrating and extruding glass |
| AT346007B (en) * | 1975-06-05 | 1978-10-25 | Wuestefeld Claus | METHOD OF MANUFACTURING FOAM GLASS |
| GB1556993A (en) * | 1975-07-17 | 1979-12-05 | Sovitec Sa | Gas-expansible bodies |
| SU716998A1 (en) * | 1978-07-24 | 1980-02-25 | Предприятие П/Я А-3843 | Method of manufacturing porous glass |
| CH637356A5 (en) * | 1978-10-06 | 1983-07-29 | Millcell Ag | BLOWING AGENTS FOR PRODUCING FOAM GLASS FROM GLASS FLOUR AND METHOD FOR THE PRODUCTION THEREOF. |
| FR2482579A1 (en) * | 1980-05-14 | 1981-11-20 | Saint Gobain Isover | PROCESS FOR MANUFACTURING EXPANDED GLASS PRODUCTS |
| DE3044130C2 (en) * | 1980-11-24 | 1985-05-09 | Veit Dennert KG Baustoffbetriebe, 8602 Schlüsselfeld | Process for the production of foam glass moldings |
| US4340407A (en) * | 1981-02-11 | 1982-07-20 | The United States Of America As Represented By The United States Department Of Energy | Method of forming cavitated objects of controlled dimension |
| DE3202623A1 (en) * | 1982-01-27 | 1983-08-04 | Henkel KGaA, 4000 Düsseldorf | METHOD FOR PRODUCING FOAMED GLASS PRODUCTS |
| EP0086599A1 (en) * | 1982-02-12 | 1983-08-24 | Redland Technologies Limited | Method and apparatus for the heat processing of particulate materials |
| JPS5964564A (en) * | 1982-06-10 | 1984-04-12 | 旭化成株式会社 | Manufacture of natural glass foam bead |
-
1984
- 1984-06-21 JP JP59127865A patent/JPS616142A/en active Granted
-
1985
- 1985-06-18 US US06/746,118 patent/US4693739A/en not_active Expired - Fee Related
- 1985-06-18 CA CA000484292A patent/CA1258588A/en not_active Expired
- 1985-06-21 GB GB08515783A patent/GB2162509B/en not_active Expired
- 1985-06-21 FR FR858509464A patent/FR2566385B1/en not_active Expired - Fee Related
- 1985-06-21 DE DE19853522291 patent/DE3522291A1/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| GB2162509B (en) | 1988-08-03 |
| DE3522291A1 (en) | 1986-01-02 |
| GB2162509A (en) | 1986-02-05 |
| JPH0520366B2 (en) | 1993-03-19 |
| FR2566385B1 (en) | 1993-01-08 |
| US4693739A (en) | 1987-09-15 |
| GB8515783D0 (en) | 1985-07-24 |
| JPS616142A (en) | 1986-01-11 |
| FR2566385A1 (en) | 1985-12-27 |
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