JP2009280446A - High strength vitreous light filler material and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an improved method for producing a vitreous light filler material which provides a high strength vitreous hollow sphere no matter what type of raw ores are used and can expand the use field as a filler material. <P>SOLUTION: The method for producing the vitreous hollow sphere comprises removing a heavy mineral from a volcanic glass raw ore, followed by roughly classifying the whole into three types, a fine-particle fraction, a middle-particle fraction, and a coarse-particle fraction, and feeding the middle-particle fraction to an internal combustion medium fluidized bed furnace as a stock. The feed stock is preheated by mixing it with exhaust gas discharged from the fluidized bed furnace and allowing heat exchange between the both. The preheated stock is then passed through a cyclone to remove the coarse-particle portion and the fine-particle portion, and only the middle-particle portion having a particle size of 7-210 μm is sent to the internal combustion medium fluidized bed furnace to be fired and foamed. The temperature of the stock mixture at the first point of contact between the feed stock and the exhaust gas is controlled in the range of 490-790°C, and the temperature of the stock mixture at an inlet port of the cyclone is controlled in the range of 100-300°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lightweight filler material comprising a high-strength glassy hollow sphere and a method for producing the same.

  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.

On the other hand, for spherical pearlite that has a multi-bubble structure consisting of open-type bubbles without taking a hollow sphere structure, natural glassy rocks that have been crushed and adjusted in particle size are preheated at a temperature lower than their softening point to reduce the water content. After adjusting the content to 0.1 to 2% by weight, and then mixing 30 to 200% by volume of a high melting point fine powder and foaming and firing it at a temperature of 900 to 1300 ° C. with a rotary kiln or electric furnace, A method of separating from a melting point fine powder (refer to Patent Document 7) and a rhyolitic non-granulated rock grain as a raw material, an average particle diameter of 5 mm or less, a sphericity of 0.7 or more, and a compressive strength of 25 N / mm ² When the above-mentioned hard foamed pearlite and rhyolitic non-granulated rock grains having an average particle size of 0.6 to 5 mm and a water content of 3 wt% or less are fired in one step, firing is performed according to the compressive strength of the foamed perlite after firing. Who chooses the temperature And the like are known (see Patent Document 8).

“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)

  Glassy hollow spheres obtained by using volcanic eruption deposits as a raw material by conventional manufacturing methods all have low resistance to shearing force, and when blended as fillers in resins, cements, etc., they have the disadvantage of being easily disintegrated by mixing operations. . Attempts have been made to reduce the size to increase pressure resistance and increase the strength as a solution, but no satisfactory results have been obtained so far.

  Under such circumstances, the present invention is an improvement that can uniformly give high-strength glassy hollow spheres regardless of the use of any ore, and can expand the field of use as a filler material. It was made for the purpose of providing a manufacturing method.

  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 earnest research, the exhaust gas from the fluidized bed furnace is obtained when the medium-sized fraction classified from the volcanic glass ore is supplied to the internal combustion medium fluidized bed furnace and calcined by specific means. By preheating the raw material under controlled temperature conditions using the, and classifying the preheated raw material with a plurality of cyclones, sending only a specific fraction into the fluidized bed furnace, and continuously firing Surprisingly, a new glassy hollow sphere with high strength was obtained, which was found to be suitable as a lightweight filler material, and based on this finding, the present invention was made.

That is, the present invention is a lightweight filler material comprising a high-strength vitreous hollow sphere characterized by having a pressure strength equivalent to a hydrostatic levitation rate of 50% or more at 8 MPa with a particle size of 10 to 300 μm for 1 minute, and a volcano After removing heavy minerals from the glass ore, the whole is roughly classified into three types: fine fraction, medium fraction and coarse fraction, and the medium fraction is used as a raw material. In the method for producing a glassy hollow sphere, the feedstock is mixed with the exhaust gas discharged from the fluidized bed furnace and preheated by exchanging heat between the two, and the preheated raw material is further recycled to a cyclone. The raw material mixture at the first contact point between the feedstock and the exhaust gas is sent to the internal-combustion medium fluidized bed furnace by excluding the coarse and fine parts, and only the medium-sized part is sent to the internal combustion medium fluidized bed furnace. The temperature of 490 to 790 ° C. and the temperature of the raw material mixture at the cyclone inlet are controlled to 100 to 300 ° C. A method for producing a lightweight filler material comprising glassy hollow spheres is provided.
The reason why a large number of cyclones are connected in the process before supplying the volcanic glass ore to the internal combustion medium fluidized bed furnace is the improvement of the ore particle shape in addition to the particle size adjustment described above. In other words, by repeating the collision of the ore particles with the inner wall of the pipe in the cyclone and the pipe, and the collision between the particles, the corners of the ore particles with an angular shape are taken and brought closer to a rounded shape. As a result, the sphericity of the glassy hollow sphere can be improved.

  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 weathered volcanic ash such as white clay and Biei white clay, and volcanic eruptions such as obsidian, pearlite, pine stone, natural pumice, mullet and kora. 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.

These volcanic glass ores have a low water content (dehydrated from room temperature to 200 ° C) of 0.3 to 13%, and a high temperature water content (dehydrated from 200 ° C to 800 ° C) of 1.8 to 6. It has different moisture content over a wide temperature range of 0%. The low-temperature water content is a dehydration amount that evaporates from room temperature to 200 ° C. at a heating rate of 10 ° C./min in thermogravimetric analysis, and the high-temperature water content is a dehydration that also evaporates from 200 ° C. to 800 ° C. It is a quantity.
In the conventional method for producing glassy hollow spheres, in order to reduce the low-temperature water content, which reduces the foaming efficiency only by removing the heat of evaporation without contributing to the foaming source, a drying process is performed in advance using a rotary kiln or dryer. It was necessary to adjust the high-temperature water content within an appropriate range while keeping the high-temperature water content that contributes as a foaming source as low as possible, and to control the temperature rise so that the water was not lost. .
In the method of the present invention, it is a rapid heating method using a fluidized bed furnace using a heat medium, and a volcanic glass raw material is mixed with hot exhaust gas discharged from a fluidized bed furnace in advance, and heat is generated between the two. Since it is a preheating method by exchanging, it is not necessary to take the above-mentioned trouble and consideration in the preliminary drying of the prior art, and heavy minerals with a particle size of 1 mm or more were removed from the volcanic glass ore such as mined pyroclastic flow deposits. There is an advantage that it can be supplied to the fluidized bed furnace as it is.

  The removal of the heavy mineral can be easily performed, for example, by classifying the ore at a room temperature and air flow classification. The heavy mineral having a particle diameter of 1 mm or more removed in this manner varies depending on the type of the ore and the production area, but is usually about 3 to 10% by mass based on the mass of the ore.

Next, the method of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing an example of an apparatus for carrying out the method of the present invention. The volcanic glass ore is supplied from the inlet 1 to the processing tower 2 where it comes into contact with the air flow blown from below at room temperature, and the specific gravity of quartz, feldspar, etc. is larger than 2.4. Only the above heavy minerals settle and are collected in the heavy mineral receiver 3, and the remaining portion is sucked by the exhaust blower 7, transported to the air flow, and enters the ore fraction zone. This ore fraction zone is composed of a reverse cyclone 4 in which the inlet and outlet of the cyclone are connected in reverse, a large-capacity cyclone 5 and a small-capacity cyclone 6, and the coarse cyclone fraction, that is, a particle size of 515 μm or more by the reverse cyclone 4 The large-volume cyclone 5 removes the fine particle fraction, that is, the fraction having a particle size of 7 μm or less, and only the medium particle fraction having a particle size of 7 μm to 515 μm is fed from the lower discharge port by the screw feeder 8 to the raw material supply pipe. Sent to. The ore fines fraction is collected by a small cyclone 6. This raw material supply pipe includes a pipe 10 through which exhaust gas discharged from an internal combustion medium fluidized bed furnace 22 which will be described later is sent, a pipe 9 through which the raw ore medium grain fraction sent from the screw feeder 8 is introduced, and a hollow sphere. The pipe 11 is composed of a mixture of the exhaust gas separated from the glassy hollow spheres by the separation cyclone 26 and the raw ore middle-grain fraction to the raw material fractionation zone.

  The ore middle-grain fraction, exhaust gas, and mixture that have passed through this raw material supply pipe are then sent to a raw material fractionation zone comprising a reverse cyclone 12, a large-capacity cyclone 14, and a connecting pipe 13 of both, and are classified. Only the medium grain fraction in the range of 210 μm is mixed with the air supplied from the compressor 20 and the fuel gas introduced from the fuel gas inlet 21 to the lower part of the fluidized bed furnace via the screw feeder 18 and the pipe 19. Pumped by gas. At this time, the fine-grained fraction classified by the large-capacity cyclone 14 is sucked together with the combustion gas, separated and recovered from the airflow by the small-capacity cyclone 16 through the pipe line 15, and the combustion gas is discharged from the exhaust blower 17.

  The internal combustion medium fluidized bed furnace 22 includes a vertically long cylindrical body 24, a dispersion plate 25 that divides the inside of the vertically long cylindrical body 24 into an upper fluidized bed forming part and a lower wind box part, and a heat medium loaded in the upper compartment. ing. The vertically long cylindrical body 24 is made of a corrosion-resistant and heat-resistant material such as stainless steel, and its size is appropriately selected according to the production amount of the target glassy hollow sphere. When implemented industrially, it is usually selected within a range of an inner diameter of 50 to 1000 mm and a height of 1 to 10 m, but there is no particular limitation.

  As the dispersion plate, a perforated plate in which holes having a diameter of 1.5 to 5 mm are drilled in a ratio of 2 to 5% in a plate of corrosion resistant and heat resistant metal such as stainless steel having a thickness of 2 to 8 mm is used. It has been. As the heat medium, a heat-resistant ceramic ball having a diameter of 2.0 to 3.5 mm, for example, a mullite ball, is used. Efficiency can be improved by using crushed mullite having a diameter of 1.7 mm or more.

  The temperature of the fluidized bed furnace can be controlled within the range of 900 to 1150 ° C. by adjusting the supply amount of the fuel gas and air mixture pumped from the compressor 20 and the ratio of the fuel gas and air. it can. The vitreous hollow spheres produced in the internal-combustion medium fluidized bed furnace 22 are sent to the cyclone 26 for separating hollow spheres through the connecting pipe 23 and collected.

  In the method of the present invention, the static bed height of the fluidized bed is 50 to 300 mm, the superficial velocity is 0.4 to 2.0 m / s, and the volcanic glass ore supply rate is 5 to 40 kg / hr. It is preferable to operate.

In the method of the present invention, in order to obtain a desired high-strength vitreous hollow sphere, the raw material mixture at the first contact point (point A in FIG. 1) between the feedstock consisting of a medium particle fraction having a particle size of 7 to 210 μm and exhaust gas is used. If the temperature is too high, foaming will result in a thin shell wall thickness (less than 1 μm), resulting in a multi-bubble hollow sphere structure with low pressure strength, so the temperature of the raw material mixture at the first contact point (point A) It is necessary to control the temperature of the raw material mixture at 490 to 790 ° C., preferably 510 to 780 ° C., and the temperature of the raw material mixture at the cyclone inlet (point B in FIG. 1) to 100 to 300 ° C., preferably 110 to 280 ° C. is there. These temperature ranges can be limited in the design of equipment such as the medium fluidized bed furnace, the cyclone connected to it, the pipes, the dimensions of the connecting pipes and their insulation coating materials, etc. This can be achieved by increasing or decreasing the feed rate of the ore and the firing temperature in the fluidized bed furnace, that is, the mixing ratio and the supply amount of the mixed gas of fuel gas and air injected into the fluidized bed furnace.
In order to obtain a desired high-strength vitreous hollow sphere, the raw material particles are preheated in a high-temperature air flow controlled in temperature in order to preheat the raw material particles uniformly in the raw material preheating step in which a plurality of cyclones are combined. It has become a very important element.
In addition, the temperature of the reverse cyclone inlet between said A point and B point is normally maintained at 305-480 degreeC.

  Next, the contents of this temperature control are summarized and shown in Table 1.

  Thus, it has a single-bubble hollow sphere structure with a particle size of 10 to 300 μm, and has a sphericity of 0.80 or more and a pressure strength equivalent to a hydrostatic levitation rate of 50% or more at 8 MPa for 1 minute. Glassy hollow spheres can be obtained with a recovery rate of 30% or more based on the type and supply of volcanic glass ore.

  The conventional glassy hollow spheres having a particle diameter of 30 to 300 μm are all multi-bubble structures, have a sphericity of less than 0.80, and a hydrostatic levitation rate of 1 MPa at 8 MPa is 41% or less. It was completely unexpected that the vitreous hollow sphere having such high sphericity and high strength was obtained by the method of the present invention.

  The conventional glassy single-bubble hollow sphere has a shell wall thickness of 1 μm or less, whereas the glassy hollow sphere has a thick shell wall with an average of 1.4 to 5.5 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 5.5 μm or more.

  In addition, the hydrostatic levitation rate at 8 MPa for 1 minute 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 measured values of the two times are averaged to obtain a hydrostatic levitation rate of 1 minute at 8 MPa.
H = [(m ₁ −m ₀ ) / S] × 100
However, m ₁ is the total mass of the glass filter and the water flotation sample (g), m ₀ is empty glass filter mass (g), S is the mass of the sample.

  Conventional commercially available volcanic glassy hollow spheres have a multi-bubble structure and have a compressive strength of 8 MPa and a low hydrostatic pressure levitation rate of 41% or less in terms of hydrostatic pressure for 1 minute. However, the filler material of the present invention has an effect that the application field can be expanded because the pressure strength in terms of the hydrostatic levitation rate for 1 minute at 8 MPa is as high as 50% or more. .

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 disposed, and a magnetic box having a diameter of 26 to 31 mm for preventing flashback was loaded on the bottom air box portion. As the heat medium, heavy minerals having a particle diameter of 1 mm or more collected from volcanic glass ore or crushed mullite having a particle diameter of 1.7 mm or more were used.

  1 was used as the volcanic glass ore using Osaki Shirasu (average particle size of 290 μm) of the Ito pyroclastic flow deposit produced in Osaki-cho, Kago-gun, Kagoshima Prefecture. That is, it was supplied from the inlet 1 to the treatment tower 2 at 45.5 kg / h for 1 hour, and 2.4 kg of heavy mineral having a particle diameter of 1 mm or more was recovered. The remaining part is transported to the air stream and enters the ore fraction zone, and 29.6 kg is recovered by the reverse cyclone 4 with the cyclone inlet and outlet connected in reverse, and the medium fraction 12.7 kg by the large capacity cyclone 5 It was recovered and 0.4 kg was recovered with a small-capacity cyclone 6. The remaining fine powder was collected by a bag filter connected in front of the exhaust blower 7.

  The reverse cyclone 4 removes the coarse-grained fraction, that is, the fraction having a particle diameter of 515 μm or more, and the large-capacity cyclone 5 removes the fine-grained fraction, that is, the fraction having a particle diameter of 8.5 μm or less. Only the medium particle fraction having a particle size of 7 μm to 515 μm was sent from the lower discharge port to the raw material supply pipe at 12.7 kg / hr by the screw feeder 8. This raw material supply pipe includes a pipe 10 through which exhaust gas discharged from an internal combustion medium fluidized bed furnace 22 which will be described later is sent, a pipe 9 through which the raw ore medium grain fraction sent from the screw feeder 8 is introduced, and a hollow sphere. The pipe 11 is composed of a mixture of the exhaust gas separated from the glassy hollow spheres by the separation cyclone 26 and the raw ore middle-grain fraction to the raw material fractionation zone.

  The mixture of the ore medium grain fraction and the exhaust gas (discharged from the hollow sphere separation cyclone 26) that has passed through the raw material supply pipe is adjusted to an airflow temperature of 524 ° C. (point A in FIG. 1), and then the reverse cyclone 12 The coarse-grained fraction is removed at (airflow temperature 308 ° C.), sent to the raw material fractionation zone consisting of both connecting pipes 13, classified while being dried in the airflow, and the medium-grain fraction in the range of particle size 7 to 210 μm. Only a minute portion of the raw material having an average particle size of 82.8 μm is recovered in the large-capacity cyclone 14 (the air temperature at the point B in FIG. 1 is 252 ° C.) and sent to the lower part of the fluidized bed furnace through the screw feeder 18 and the pipe 19. Then, it is pumped by a mixed gas of air and fuel gas supplied by the compressor 20.

  The internal combustion medium fluidized bed furnace 22 includes a heat-resistant stainless steel vertical cylinder 24 (inner diameter 129 mm, height 1.8 m) and a dispersion plate 25 that divides the inside into an upper fluidized bed forming portion and a lower windbox portion. And a heat medium loaded in the upper compartment.

  As the dispersion plate 25, a perforated plate in which holes having a diameter of 1.7 mm were formed in a stainless steel plate having a thickness of 4 mm at a rate of 2.9% was used. As the heat medium, 2.2 kg of heavy mineral having a particle diameter of 1 mm or more separated and removed from the Osaki Shirasu ore by the treatment tower 2 was used.

  The temperature of the fluidized bed furnace was controlled at 1050 ° C. ± 5 ° C. by adjusting the supply amount of the fuel gas / air mixture pumped from the compressor 20 and the ratio of the fuel gas / air. The fluidized bed was operated at a static bed height of 122 mm and a superficial velocity of 1.1 m / s with a shirasu raw material supply rate of 8.9 kg / hr in the screw feeder 18.

  The shirasu raw material was foamed through an internal-combustion medium fluidized bed furnace 22 to become glassy hollow spheres, conveyed to the exhaust gas, and separated from the exhaust gas by the cyclone 26 for separating the hollow spheres. The yield of the high-strength glassy hollow spheres obtained by separating the collected glassy hollow spheres with water is 45.7%, the average particle size is 112.5 μm, the loose apparent specific gravity is 0.56, and the hydrostatic pressure levitation rate. Was 75.0%. Loose apparent specific gravity is measured by depositing test powder in a dedicated metal cup (internal volume 100 ml) through a dedicated vibrating screen in 20-30 seconds using a Hosokawa Micron powder tester PT-E type. did.

  An electron micrograph (using JSM-840 manufactured by JEOL Ltd., acceleration voltage 15 kV, secondary electron image) of the high-strength glassy hollow sphere is shown in FIG. Its sphericity was 0.87. The sphericity is taken as a ratio of the maximum diameter MD and the diameter BD (BD / MD) perpendicular to this by taking a photograph with an electron microscope magnification of 150 times. The closer the sphericity is to 1, the closer to the sphere. Become. In this example, the average value of 20 measurements was taken as the value of sphericity.

  An electron micrograph of a typical particle cross section of a high-strength glassy hollow sphere is shown in FIG. The shell wall thickness was 5.5 μm. The film thickness of the shell wall was determined by dispersing glassy hollow spheres in cold-embedded epoxy resin, curing at room temperature for 24 hours, rough polishing with No. 320 water-resistant abrasive paper, and precision polishing with No. 2400 water-resistant abrasive paper. After drying, the gold-deposited material was observed with an electron microscope, and four points on the shell wall in the particle cross section of the glassy hollow sphere were measured, and the average value was calculated.

For the volcanic glass ore, the average particle size of the Oshira Shirasu of the Ito pyroclastic flow deposit produced in Osaki-cho, Kagoshima Prefecture, using a collision plate type JET airflow crushing and classifying device (IDS-2 type manufactured by Nippon Pneumatic Industry) A product pulverized to 26.7 μm was used in the same manner as in Example 1. However, the supply amount of the shirasu raw material of the screw feeder 18 in FIG. 1 was changed to 9.0 kg / hr, and the temperature was controlled at 1050 ° C. ± 5 ° C. by the internal combustion medium fluidized bed furnace 22. At this time, the temperature at point A in FIG. 1 was 508 ° C., and the temperature at point B was 246 ° C.
The yield of high-strength vitreous hollow spheres having a single-bubble hollow sphere structure obtained by floating water separation of the vitreous hollow spheres collected by the cyclone 26 for separating hollow spheres in FIG. 1 is 37.0%. The diameter was 76.2 μm, the loose apparent specific gravity was 0.61, and the hydrostatic levitation rate for 1 minute was 55.0% at 8 MPa.
The sphericity of the high-strength glassy hollow sphere was 0.80, and the film thickness of the shell wall of the particle cross section was 2.2 μm.

A pearlite fine powder (average particle size 18.1 μm) obtained by crushing pearlite from Hyogo Prefecture was used as the volcanic glass ore in the same manner as in Example 1. However, the supply amount of the shirasu raw material of the screw feeder 18 in FIG. 1 was changed to 5.4 kg / hr, and the temperature was controlled at 1130 ° C. ± 5 ° C. by the internal combustion medium fluidized bed furnace 22. As the heat medium, 3.2 kg of mullite crushed material having a particle size of 1.7 to 2.8 mm manufactured by ITOCHU CERATECH was used. The temperature at point A in FIG. 1 at this time was 614 ° C., and the temperature at point B was 287 ° C.
The yield of high-strength vitreous hollow spheres having a single-bubble hollow sphere structure obtained by floating water separation of vitreous hollow spheres collected by cyclone 26 for separating hollow spheres in FIG. The diameter was 73.0 μm, the loose apparent specific gravity was 0.39, and the hydrostatic levitation rate for 1 minute was 60.0% at 8 MPa.
An electron micrograph of the high-strength glassy hollow sphere is shown in FIG. Its sphericity was 0.89.
The film thickness of the shell wall of a typical particle cross section of the high-strength glassy hollow sphere was 1.4 μm.

A pearlite fine powder (average particle size 25.3 μm) obtained by pulverizing pearlite from the People's Republic of China was used as the volcanic glass ore in the same manner as in Example 1. However, the supply amount of the shirasu material of the screw feeder 18 in FIG. 1 was changed to 8.3 kg / hr, and the temperature was controlled at 1130 ° C. ± 5 ° C. by the internal-combustion medium fluidized bed furnace 22. As the heat medium, 3.2 kg of mullite crushed material having a particle size of 1.7 to 2.8 mm manufactured by ITOCHU CERATECH was used. At this time, the temperature at point A in FIG. 1 was 621 ° C., and the temperature at point B was 299 ° C.
The yield of high-strength vitreous hollow spheres having a single-bubble hollow sphere structure obtained by floating separation of vitreous hollow spheres collected by cyclone 26 for separating hollow spheres in FIG. The diameter was 70.2 μm, the loose apparent specific gravity was 0.45, and the hydrostatic pressure levitation rate for 1 minute was 63.5% at 8 MPa.
An electron micrograph of the high-strength glassy hollow sphere is shown in FIG. Its sphericity was 0.87.
The film thickness of the shell wall of the typical particle cross section of the high-strength glassy hollow sphere was 1.7 μm.

Comparative Example For comparison, Table 2 shows the hydrostatic levitation rate, sphericity, and shape of a commercially available shirasu balloon.

  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 1 μm or less as a whole. 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.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic solution which shows one example of the apparatus for implementing this invention method. The electron microscope surface photograph figure of the high intensity | strength glassy hollow sphere obtained in Example 1. FIG. The electron microscope cross-sectional photograph figure of the high intensity | strength glassy hollow sphere obtained in Example 1. FIG. The electron microscope surface photograph figure of the high intensity | strength glassy hollow sphere obtained in Example 3. FIG. The electron microscope surface photograph figure of the high intensity | strength glassy hollow sphere obtained in Example 4. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input port 2 Processing tower 3 Heavy mineral receiver 4, 12 Reverse cyclone 5, 14 Large capacity cyclone 6, 16 Small capacity cyclone 7, 17 Exhaust blower 8, 18 Screw feeder 9, 10, 11, 15, 19 Pipe 13 , 23 Connecting pipe 20 Compressor 21 Fuel gas inlet 22 Internal combustion medium fluidized bed furnace 24 Long cylindrical body 25 Dispersion plate 26 Cyclone for separating hollow spheres

Claims (8)

  A lightweight filler material comprising a high-strength glassy hollow sphere having a pressure strength equivalent to a hydrostatic levitation rate of 50% or more at 8 MPa with a particle size of 10 to 300 μm for 1 minute.   A lightweight filler material comprising the high-strength vitreous hollow sphere according to claim 2 having a sphericity of 0.80 or more.   A lightweight filler material comprising a high-strength vitreous hollow sphere according to claim 1 or 2 having a single-bubble hollow structure.   After removing the heavy minerals from the volcanic glass ore, the whole is roughly classified into three types: a fine-grained fraction, a medium-grained fraction, and a coarse-grained fraction. In the method for producing a glassy hollow sphere by supplying to the furnace, the feedstock is mixed with the exhaust gas discharged from the fluidized bed furnace and preheated by heat exchange between them, Through the cyclone, excluding the coarse and fine parts, only the medium part of the particle size of 7 to 210 μm is sent to the internal combustion medium fluidized bed furnace, fired and foamed, and the raw material at the first contact point between the above feed and exhaust gas A method for producing a lightweight filler material comprising glassy hollow spheres, wherein the temperature of the mixture is controlled to 490 to 790 ° C, and the temperature of the raw material mixture at the cyclone inlet is controlled to 100 to 300 ° C.   5. The method for producing a lightweight filler material comprising a high-strength vitreous hollow sphere according to claim 4, which has a compressive strength corresponding to a hydrostatic levitation rate of 50% or more at 8 MPa with a particle size of 10 to 300 [mu] m for 1 minute.   The method for producing a lightweight filler material comprising a high-strength vitreous hollow sphere according to claim 4 or 5, having a sphericity of 0.80 or more.   A method for producing a lightweight filler material comprising a high-strength vitreous hollow sphere according to any one of claims 4 to 6, which has a single-bubble hollow structure.   The manufacturing method of the lightweight filler material in any one of Claim 4 thru | or 7 which uses the heavy mineral with a particle size of 1 mm or more removed from the volcanic glass ore as a heat medium in an internal combustion medium fluidized bed.