JP5035563B2 - Manufacturing method of high strength, high sphericity glassy fine hollow sphere - Google Patents

Description

  The present invention relates to a novel method for producing a high strength, high sphericity glassy fine hollow sphere suitable as a lightweight filler material.

  Among lightweight fillers, glassy hollow microspheres are lightweight and heat resistant, and are isotropic, so they can impart impact resistance without giving anisotropy to the matrix material, and fluidity In addition, it is widely used as a filler for cement-based building materials, paper clay, and plastics (see Non-Patent Document 1).

  Shirasu balloon, which is representative of this glassy micro-hollow sphere, is made by firing and foaming shirasu of glassy volcanic eruption deposits, but since the raw materials are readily available and can be foamed relatively easily, Since its development, many manufacturing methods have been proposed.

  As a manufacturing method of this shirasu balloon, first, a method of firing using an electric furnace or a rotary kiln is performed. For example, shirasu is classified and fine particles are separated, and this is divided into 800 to 1200 by an electric furnace or an external heating rotary kiln. There is known a method for producing fine hollow glass spheres (see Patent Document 1) by performing specific gravity separation in water (hereinafter referred to as floating water separation) or air classification after heat treatment at 10 ° C. for 10 seconds to 10 minutes.

Thereafter, a method for producing a foamed material using a high-temperature fluidized bed was developed (see Patent Document 2), and a method for producing glassy hollow microspheres using an internal combustion heat medium fluidized bed furnace using the same dominates. So far, fine hollow particles in which a mixture of fine particles of volcanic glassy deposits and a hydrophilic reducing agent that reduces the hydrophilicity of the fine particles is heat treated at 900 to 1200 ° C. using a fluidized bed heating furnace. A method for producing glass spheres (see Patent Document 3), obtained by foaming a volcanic glass raw material having an average particle diameter of 20 μm or less and containing particles of 40 μm or more in a range of 25% to 48% in an internal fluidized bed furnace. the air flow containing the hollow glass, tapping bulk density 0.25 g / cm ³ or less is supplied to the plurality of cyclones which are coupled in series, different average particle size 20μm or less of the hollow glass microspheres and the mean particle size of 2 A method for continuously producing spherical glass spheres of the kind or higher (see Patent Document 4), using ceramic balls in an internal fluidized bed furnace, supplying a mixed gas of fuel gas and air to the ceramic balls, The ceramic ball is heated to 900 ° C. or higher with the combustion heat of the fuel gas, and the temperature is controlled within the set temperature ± 3 ° C., and at the same time, the raw material powder of the fine hollow glass sphere is supplied along with the mixed gas. (See Patent Document 5), natural pumice is supplied to the fluidized bed from the exhaust side of the internal combustion heat medium fluidized bed furnace, calcined at 900 to 1100 ° C., and loose apparent specific gravity is 0 A continuous production method of fired foamed pumice stone of 18 to 0.31 (see Patent Document 6) has been proposed so far.

  However, the glassy hollow spheres obtained from the volcanic eruption deposits as a raw material by the conventional manufacturing method are all less resistant to shearing force, and when blended as fillers in resins, cements, etc., they are prone to collapse by mixing operations There is. Attempts have been made to increase the pressure resistance and increase the strength as a solution to this problem, but no satisfactory results have been obtained so far, and the quality is not constant depending on the type of raw material used. .

“Industrial Materials”, published by Nikkan Kogyo Shimbun, Volume 42, 1994, p. 102-111 Japanese Patent Publication No. 48-17645 (claims and others) Japanese Patent Publication No. 51-22922 (claims and others) Japanese Patent Publication No. 7-24299 (Claims and others) JP 2002-338280 A (Claims and others) Japanese Patent Laid-Open No. 11-11960 (Claims and others) JP 2004-91283 A (Claims and others) JP-A-9-183612 (Claims and others) JP 2007-320805 A (Claims and others)

  Under such circumstances, the present invention is a novel improved so that a glassy hollow sphere having high strength and high sphericity can be obtained regardless of the type of raw material used. It is made for the purpose of providing the manufacturing method of a glassy fine hollow sphere.

  The present inventors have developed a novel method capable of obtaining glassy hollow spheres with significantly higher strength than conventional glassy hollow spheres using any of a wide variety of glassy volcanic products as raw materials. As a result of intensive research to achieve this, two-stage firing is performed under different firing conditions when firing raw materials that are classified and have a specific particle size range using an internal combustion medium fluidized furnace. Thus, it was found that the object can be achieved, and the present invention has been made based on this finding.

  That is, the present invention removes heavy minerals from volcanic glass ore and classifies them in a method for producing glassy fine hollow spheres by firing volcanic glass ore using an internal combustion medium fluidized bed furnace. The raw material is obtained by subjecting a fraction having an average particle size of 15 to 150 μm obtained by drying to a low temperature water content of 0.1 to 0.4% and a high temperature water content of 1.0 to 1.8%. First, at the temperature of 900 to 1050 ° C., the first stage baking is performed until the low-temperature water content is almost lost, and then the obtained heat-treated product (hereinafter referred to as the first stage baking powder) is further in the range of 1050 to 1150 ° C. And high-strength with a hydrostatic pressure levitation rate of 45% or more and a sphericity of 0.80 or more at 8 MPa for 1 minute, characterized by performing the second-stage firing at a temperature higher than the temperature of the first-stage firing. , Manufacturing method of high sphericity glassy fine hollow sphere It is intended to provide.

  As the volcanic glass ore used in the method of the present invention, Shirasu used for the production of ordinary Shirasu balloons, for example, Kakuto Shirasu, Yoshida Shirasu, as well as Shirasu as a raw material for producing glassy hollow spheres. There are volcanic eruptions such as weathered volcanic ash such as white clay and Biei white clay, obsidian, pearlite, pine stone, natural pumice, mullet, and cola. According to the method of the present invention, pyroclastic flow deposits such as shirasu forming a shirasu plateau in south Kyushu, which is considered unsuitable as a raw material for shirasu balloons because of its large amount of heavy minerals, can be used. In addition, Kanuma soil composed of weathered pumice that is mainly composed of volcanic glass and Kanoya soil in Minami Kyushu can be used in the same manner.

  Generally, the volcanic glass ore has a low-temperature water content (dehydration amount from room temperature to 200 ° C.) of 0.3 to 13%, and a high-temperature water content (dehydration amount from 200 ° C. to 800 ° C.) of 1.8 to 6. It has different moisture content over a wide temperature range of 0%. Here, the low-temperature water content is a dehydration amount that evaporates from room temperature to 200 ° C. at a rate of temperature increase of 10 ° C./min in thermogravimetric analysis, and the high-temperature water content is also from 200 ° C. to 800 ° C. The amount of dehydration that evaporates.

  Among these, low-temperature water content hardly contributes as a foaming source and reduces the foaming efficiency just by taking the heat of evaporation, so various types such as rotary kilns, fluidized bed dryers, vibration dryers, air dryers, infrared dryers, etc. It is preferable to reduce this by carrying out a high-temperature drying process in advance with a high-temperature dryer or the like.

Further, the high-temperature water content acts as a foaming source, and if it is too much, it causes over-foaming during firing, so it must be reduced to 1.8% or less by high-temperature drying treatment. If the water content at high temperature is higher than 1.8%, it is over-foamed by firing in an internal medium fluidized bed furnace, and has a low-strength glassy hollow microsphere with a multi-bubble structure similar to that of the conventional shirasu balloon or pearlite. Will be manufactured. In this first stage firing, if it foams to form a multi-bubble structure, it is very difficult to change the internal structure of the glassy fine hollow sphere to a single foam structure even in the second (second stage) firing. Since it is difficult, it is very important to reduce it to 1.8% or less by high-temperature drying treatment.
On the other hand, if the high-temperature moisture content is too small, foaming is difficult in the second-stage firing stage after the first-stage firing. Therefore, as a measure of the heat load of the high-temperature drying treatment, the high-temperature moisture content of the raw material is 1.0. % Or more should be kept.

  However, the raw material whose high-temperature water content is adjusted to 1.8% or less by the high-temperature drying treatment is hardly foamed even when fired at the firing temperature of 950 to 1050 ° C. (first stage) using an internal medium fluidized bed furnace. Does not happen. This can be seen from the fact that the raw material and the powder after firing were observed with an electron microscope and there was no difference from the original shape.

  The first-stage fired powder obtained by firing at a firing temperature of 950 to 1050 ° C. has a low water content of zero and a high water content of 1.0% or less. For this reason, even if it bakes once again on the same conditions as 1st step | paragraph baking, it will hardly foam. However, the conditions under which the heat load in the medium fluidized bed furnace is increased, that is, the amount of the heat medium is made larger than that during the first stage firing, for example, the stationary layer height of the heat medium is set to 100 to 300 mm, and the first stage When firing at a temperature higher than the firing (second-stage firing), surprisingly, a high-strength vitreous fine hollow sphere having a high sphericity and a single-bubble structure can be efficiently produced.

  As a result of repeating the experiment of the glassy fine hollow sphere by the two-stage firing (hereinafter referred to as irregular two-stage firing) under different conditions as described above, the high strength glassy fine hollow having a high sphericity and a single-bubble structure is obtained. In order to produce spheres, it has been found that it is important not to foam in the first stage firing but to foam in the second stage firing stage.

  Thus, in the first stage firing, the firing temperature is lowered (900 to 1050 ° C.) using an internal medium fluidized bed furnace in accordance with the high temperature water content of the raw material that has been subjected to high temperature drying treatment to adjust the high temperature water content. Therefore, it is necessary to perform firing under conditions that suppress foaming as much as possible. In the second stage firing, the heat load is higher than that in the first stage firing (the heat medium stationary layer height is 100 to 300 mm), and the firing temperature is 50 to 200 ° C. higher than the first stage firing condition. The desired glassy fine hollow sphere can be obtained in a high yield by firing with. And if the high-temperature water content of the raw material is less than 0.4%, foaming is difficult in the second stage firing, so the high-temperature water content of the raw material needs to be 0.4% or more.

Therefore, in the method of the present invention, the high-temperature water content necessary as a foaming source is obtained for the fraction having an average particle size of 15 to 150 μm obtained by first removing and classifying the heavy mineral having a particle size of 1 mm or more from the volcanic glass ore. It is preferable to perform the high-temperature drying treatment under such conditions that the low-temperature water content is reduced while maintaining the proper range. This high-temperature drying treatment is performed by, for example, high-temperature drying at a temperature of 250 to 790 ° C. for 1 minute to 7 hours.
Usually, the low temperature water content is adjusted to 0.1 to 0.4% and the high temperature water content is adjusted to 1.0 to 1.8% by this high temperature drying treatment.

  For the above-mentioned volcanic glass ore, the classification performed prior to the high-temperature drying treatment may be performed using means commonly used for classification, and there is no particular limitation. Examples of such classification means include sieving using a vibration sieve and classification using a wind screen.

In the method of the present invention, the average particle size obtained as described above is 15 to 150 μm, and the low temperature water content is adjusted to 0.1 to 0.4% and the high temperature water content is adjusted to 1.0 to 1.8%. It is necessary that the volcanic glass raw material be fired irregularly in two stages with different conditions using an internal combustion medium fluidized bed furnace.
According to the method of the present invention, usually a mixture of a single-bubble hollow structure and a multi-bubble hollow structure is produced, but the low-temperature water content is 0.10 to 0.15% and the high-temperature water content is increased by high-temperature drying treatment. By using a product adjusted to 1.55 to 1.75%, it is possible to produce fine hollow spheres consisting essentially of a single-bubble hollow structure.

  Therefore, the first stage firing is performed at a firing temperature of 900 to 1050 ° C., preferably 950 to 1050 ° C., and the second stage firing is performed under the condition that the heat load is larger than that of the first stage firing, The heating layer has a static layer height of 100 to 300 mm, and the second stage baking temperature is 25 to 250 ° C., preferably 50 to 200 ° C. higher than the first stage temperature, ie, 1050 to 1150 ° C., preferably Is preferably fired at a temperature within the range of 1050 to 1130 ° C. When the firing temperature of the internal combustion medium fluidized bed furnace is less than 900 ° C., complete combustion is difficult and abnormal explosion occurs and it is difficult to form a stable high-temperature fluidized state. On the other hand, when firing at a temperature higher than 1150 ° C., the volcanic glass raw material is likely to melt and adhere to the heat medium, and the fluidized bed is likely to be blocked.

  The first stage firing is performed until the low-temperature water content in the volcanic glass raw material is almost lost and the high-temperature water content is 0.4 to 1.1%, preferably 0.5 to 1.0%. The second stage baking is performed until the high-temperature water content becomes 0.0 to 0.4%. In an internal-combustion medium fluidized bed furnace, all of the processing required for it is completed in an extremely short time of 1 second or less.

Thus, a glass micro hollow sphere having an average particle size of 20 to 300 μm, a hydrostatic pressure levitation rate of 45 to 80% for 1 minute at 8 MPa, a high strength of high sphericity of 0.80 to 0.95, and high sphericity. can get.
As the supply flow rate of the combustion air in this case, a range of 40 to 60 Nm ³ / hour is usually selected.

  Next, the method of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a schematic cross-sectional view showing an embodiment of the method of the present invention, and a volcanic glass raw material having an average particle diameter of 15 to 150 μm from which heavy minerals have been removed in advance is filled in a raw material hopper 1 and is screwed by a screw feeder 2. A fuel gas sent from the fuel gas supply pipe 4, for example, a mixed raw gas of LP gas and air, is introduced from the bottom of the internal combustion medium fluidized bed furnace 8 through the raw material supply pipe 3. High pressure air is pumped to the fuel gas by the blower 5 through the air conditioner 6 and by the injection feeder 7. The volcanic glass raw material is conveyed by a mixed gas by the injection feeder 7 in contact with high-pressure air to disperse the particles apart.

  The internal combustion medium fluidized bed furnace 8 is divided into upper and lower parts by a distribution plate 9, and an upper part is filled with a heat medium 10 and a lower part is filled with a magnetic ball 11 for preventing backfire. As this heat medium, a heat-resistant ceramic having a diameter of 2.0 to 3.5 mm, for example, a mullite ball, is used. In the present invention, a heavy mineral having a particle diameter of 1 mm or more previously removed from a volcanic glass ore. Or crushed mullite having a particle size of 1.7 mm or more can be used. Further, as the dispersion plate 9, holes having a diameter of 1.5 to 5 mm are drilled in a ratio of 2 to 5% in a plate-like body of a corrosion-resistant and heat-resistant metal, for example, stainless steel having a thickness of 2 to 8 mm. Perforated plates are used.

  The mixed raw gas is brought into contact with a heat medium that has been preheated to a high temperature on a dispersion plate and is ignited and burned instantaneously and explosively, so that the heat medium is fluidized more intensely than when it is unburned. It becomes a heat source to maintain The temperature of the fluidized bed furnace is monitored by the thermocouple 12 brought into contact with the heat medium, and the temperature control of the set temperature ± 5 ° C. or less is achieved by adjusting the flow rate by the fuel gas regulator 13 according to the set temperature. Yes.

  The volcanic glass raw material is transported by a mixed gas, passes through a dispersion plate 9, and in a fluidized bed furnace 8 whose temperature is controlled at 900 ° C. or higher, particles are dispersed in a dispersed manner from a high-temperature heat medium or combustion gas. Within a second of being exposed to the intense infrared rays of the gas and being discharged with the combustion gas, a rapid heat exchange with the combustion gas and heat medium takes place, and the volcanic glass raw material instantly softens. The water contained in the gas is gasified (steamed) like a steam explosion, and is instantly fired and foamed to form glassy fine hollow spheres.

  The obtained vitreous fine hollow sphere is conveyed to the combustion gas, passes through the extraction pipe 14, is separated from the air current by the cyclone 15, and is collected in the product hopper 16.

  When using a volcanic glass raw material whose high-temperature water content is adjusted to 1.8% or less, it does not foam even when it passes through the fluidized bed furnace 8, but in this case as well, the first stage heat-treated in the first stage firing The calcined powder is conveyed to the combustion gas, passes through the extraction pipe 14, is separated from the air current by the cyclone 15, and is collected in the product hopper 16.

  In the figure, 17 is a heat insulating material, and 18 and 19 are open / close valves. 20 in the figure is an explosion-proof valve for preventing explosion.

  The first-stage fired powder collected in the product hopper 16 in the first-stage firing at a firing temperature of 900 to 1050 ° C. is once taken out from the opening / closing valve 19. It is supplied once again to the raw material hopper 1 and this time, the firing conditions are changed, the stationary layer height of the heat medium is set to 100 to 300 mm, the second stage firing is performed at a firing temperature of 1050 to 1150 ° C., and the foaming is performed for the first time. The cyclone 15 separates the air current from the air current, and glassy fine hollow spheres are collected in the product hopper 16.

  First-stage firing of an internal combustion medium fluidized bed furnace having the same structure as that shown in FIG. 1 is prepared by using two units for first-stage firing and second-stage firing, and is taken out from the opening / closing valve 19 of the first-stage firing apparatus. It can also be continuously produced by supplying the powder to the raw material hopper 1 through the opening / closing valve 18 of the second stage baking apparatus.

  The temperature of the fluidized bed furnace is controlled within the range of 900 to 1050 ° C. for the first stage firing and 1050 to 1150 ° C. for the second stage firing by adjusting the fuel gas supply rate according to the monitor temperature of the thermocouple. be able to. In the method of the present invention, the supply amount of air can be adjusted according to the monitoring temperature of the thermocouple after the supply amount of air is fixed to an appropriate value in advance according to the supply amount of the volcanic glass raw material. preferable. The height of the stationary bed of the fluidized bed is preferably adjusted within a range of 30 to 300 mm in accordance with predetermined firing conditions.

  Thus, a novel vitreous material having a hollow sphere structure with a particle size of 10 to 300 μm and a sphericity of 0.80 or more and a compressive strength equivalent to a hydrostatic levitation rate of 45% or more for 1 minute at 8 MPa. Fine hollow spheres can be obtained with a recovery rate of 25% or more based on the type and supply of volcanic glass ore.

  All the conventional glassy hollow spheres having a particle size of 30 to 300 μm have a sphericity of less than 0.80, and the hydrostatic levitation rate at 8 MPa for 1 minute is 41% or less. It was completely unexpected that such a vitreous hollow sphere having high sphericity and high strength was obtained.

  The conventional glassy single-bubble hollow sphere has a shell wall thickness of 1 μm or less, whereas the glassy fine hollow sphere has a thick shell wall with an average of 1.4 to 3.8 μm. There is also a clear structural difference between the two. Furthermore, according to the present invention, it is also possible to produce glassy fine hollow spheres having a film thickness of 3.8 μm or more.

  In addition, the hydrostatic levitation rate at 8 MPa for 1 minute, which is used as a factor indicating the pressure strength in the present invention, is the shirasu described in the VSI workshop standard published by the VSI workshop “Volcanic ejecta that builds a new era”. It is a factor indicating the pressure resistance of the balloon, and is the only standard that is practically used to express the pressure resistance of the shirasu balloon. It is measured by the following method.

A predetermined amount of sample is placed in a sample container formed by contacting a mesh sieve of JIS Z 8801 with a nominal size of 32 μm on the top and bottom of a transparent plastic pipe with an inner diameter of 20.0 ± 0.5 mm and a height of 70.0 ± 0.5 mm. Is submerged in a pressure vessel filled with water having an effective height of 1.2 times or more of the sample vessel.
Next, the pressure vessel is sealed, the internal pressure is increased to 8 MPa over 1 minute or more, and the pressure vessel is held for 1 minute or more. Then, the pressure vessel is opened and the sample vessel is taken out. Next, the entire contents of the sample container are transferred to a floatation / sink separator, and after the floated material and sediment are completely separated, the floated material is poured into a crucible glass filter and suction filtered. Next, the crucible glass filter is dried at 105 ± 2 ° C. for 8 hours or more. This operation is repeated twice. The hydrostatic levitation rate H (mass%) is obtained according to the following formula for each, and the two measurements are averaged to obtain a hydrostatic levitation rate of 1 minute at 8 MPa.
H = [(m ₁ −m ₀ ) / S] × 100
Here, m ₁ is the total mass (g) of the glass filter and the floating sample in water, m ₀ is the mass (g) of the empty glass filter, and S is the mass of the sample.

  According to the method of the present invention, a fine glass hollow sphere having high strength and high sphericity, which could not be obtained by the conventional method, can be obtained. For example, the use range when using the fine glass hollow sphere as a filler is remarkably expanded. can do.

  In addition, according to the present invention, the water sediment obtained by flotation separation of the first-stage fired powder or the heat-treated product after the second-stage fire was disposed of as a product that failed to foam in the prior art. However, if the moisture content at a high temperature is 0.4 to 1.1%, the same conditions as in the second-stage firing in the present invention or a condition where the heat load is further increased (the stationary layer height of the heat medium is set to 100 to 300 mm, If firing is performed at a firing temperature of 50 to 200 ° C. higher than the previous time, high-strength vitreous fine hollow spheres having a high sphericity and a single-bubble structure can be produced.

Next, the best mode for carrying out the present invention will be described by way of examples.
In each example, as an internal combustion medium fluidized bed furnace, a hole having a diameter of 1.7 mm is opened in a stainless steel plate having a thickness of 4.0 mm in a stainless steel cylindrical container having an inner diameter of 129 mm and a height of 1.8 m. A dispersion plate provided at a ratio of 2.9% was arranged, and a bottom air box portion loaded with magnetic balls having a diameter of 26 to 31 mm for explosion prevention was used. As the heat medium, crushed mullite having a particle size of 1.7 to 2.8 mm manufactured by ITOCHU CERATECH was used.

Examples 1-5
Using the glass raw materials shown in Table 1, two-stage baking was performed under the baking conditions shown in Table 1. Table 1 shows the physical properties of the obtained volcanic glass fine hollow body.

As can be seen from this table, all of the vitreous fine hollow spheres obtained by the method of the present invention had a hydrostatic pressure levitation rate of 45% or more at 8 MPa and 1 minute, and a sphericity of 0.80 or more. It was.
In addition, the surface SEM photograph of the glassy fine hollow sphere obtained in Example 2 is shown in FIG. 2, the cross-sectional SEM photograph is shown in FIG. 3, and the surface SEM photograph of the glassy fine hollow sphere obtained in Example 3 is shown. 4, a cross-sectional SEM photograph is shown in FIG. 5, a surface SEM photograph of the glassy fine hollow sphere obtained in Example 4 is shown in FIG. 6, and a cross-sectional SEM photograph is shown in FIG.

Comparative Example 1
In Example 2, crushed mullite having a particle size of 1.7 to 2.8 mm made by ITOCHU CERATECH was used as a heat medium from a volcanic glass raw material produced in Kakuto, Ebino City, Miyazaki Prefecture, which was not subjected to a high temperature drying treatment at 300 ° C. for 6 hours. FIG. 8 shows a surface SEM photograph of a glassy fine hollow sphere obtained by water-separating a product obtained by performing only the first stage baking process at a baking temperature of 1050 ° C. under a condition of 1.5 kg (static layer height of 77 mm). A cross-sectional SEM photograph is shown in FIG. It can be seen that most of the particles have a multi-bubble structure. The hydrostatic pressure levitation rate and sphericity measured at 8 MPa for 1 minute were 35.0% and 0.78, respectively.

Comparative Example 2
In Example 3, crushed mullite 1 having a particle size of 1.7 to 2.8 mm manufactured by ITOCHU CERATECH was used as a heat medium from a volcanic glass raw material produced in Kakuto, Ebino City, Miyazaki Prefecture, which was subjected to a high temperature drying treatment at 300 ° C. for 6 hours. FIG. 10 shows a surface SEM photograph of the first-stage fired powder obtained by performing only the first-stage firing at a firing temperature of 950 ° C. under the condition of 0.5 kg (static layer height 77 mm). None of the particles had any trace of foaming, and the volcanic glass material was subjected to high temperature drying treatment at 300 ° C. for 6 hours to reduce the high temperature water content to 1.6% or less. You can see that it will not.

Reference Example Table 2 shows the hydrostatic levitation rate, sphericity, and shape of a commercially available shirasu balloon at 8 MPa for 1 minute.

  Thus, the commercially available shirasu balloons are non-uniform in shape, mostly foamy, and all have a hydrostatic levitation rate of 41% or less and a shell wall thickness of generally 1 μm or less. It is very thin and the sphericity is less than 0.80.

  The present invention is useful as a method for producing a vitreous fine hollow sphere suitable as a lightweight filler material.

The cross-sectional schematic solution which shows the embodiment of the method of this invention. The electron microscope surface photograph figure of the glassy fine hollow sphere obtained in Example 2. FIG. The electron microscope cross-sectional photograph figure of the glassy fine hollow sphere obtained in Example 2. FIG. The electron microscope surface photograph figure of the glassy fine hollow sphere obtained in Example 3. FIG. The electron microscope cross-sectional photograph figure of the glassy fine hollow sphere obtained in Example 3. FIG. The electron microscope surface photograph figure of the glassy fine hollow sphere obtained in Example 4. FIG. The electron microscope cross-sectional photograph figure of the glassy fine hollow sphere obtained in Example 4. FIG. The electron microscope surface photograph figure of the glassy fine hollow sphere obtained by the comparative example 1. FIG. The electron microscope cross-sectional photograph figure of the glassy fine hollow sphere obtained by the comparative example 1. FIG. The electron microscope surface photograph figure of the 1st stage baking powder obtained in the comparative example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raw material hopper 2 Screw feeder 3 Raw material supply pipe 4 Fuel gas supply pipe 5 Blower 6 Air regulator 7 Injection feeder 8 Internal combustion medium fluidized bed furnace 9 Dispersion plate 10 Heat medium 11 Magnetic ball 12 Thermocouple 13 Fuel gas regulator 14 Extraction pipe 15 Cyclone 16 Product hopper 17 Heat insulating material 18, 19 Open / close valve 20 Explosion-proof valve

Claims (4)

  In the method of producing glassy fine hollow spheres by firing volcanic glass ore using an internal combustion medium fluidized bed furnace, the average particle size obtained by removing and classifying heavy minerals from volcanic glass ore A 15 to 150 μm fraction was subjected to a high temperature drying treatment and adjusted to a low temperature water content of 0.1 to 0.4% and a high temperature water content of 1.0 to 1.8%. The first stage firing is performed until the low-temperature water content is almost eliminated at the temperature of the second stage, and the obtained heat-treated product is further in the range of 1050 to 1150 ° C. and at a temperature higher than the temperature of the first stage firing. A method for producing a high strength, high sphericity glassy fine hollow sphere having a hydrostatic pressure levitation rate of 45% or more and a sphericity of 0.80 or more at 8 MPa for 1 minute, characterized by performing firing.   The manufacturing method of the high intensity | strength and high sphericity glassy fine hollow sphere of Claim 1 which performs a 1st step baking at 950-1050 degreeC and a 2nd step baking at 1050-1130 degreeC. The manufacturing method of the high intensity | strength and high sphericity glassy fine hollow sphere of Claim 1 or 2 performed by supplying combustion air at 40-60 Nm < ³ > / hour.   4. A single-bubble hollow structure is obtained using a raw material that has been subjected to a high-temperature drying treatment and adjusted to a low-temperature water content of 0.10 to 0.15% and a high-temperature water content of 1.55 to 1.75%. The manufacturing method of the high intensity | strength and high sphericity glassy fine hollow sphere in any one.