JP2003002710A - Expanded granule and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently fire a lightweight foamed body without fusing. SOLUTION: In the method for producing expanded granules, when a granulated material using a water-soluble binder is fired to obtain expanded granules, the granulated material is coated in the dry state with a fusion inhibitor by rolling and then fired together with a smaller amount of the fusion inhibitor than the amount of the fusion inhibitor used for the coating. In the method for producing expanded granules, the granulated material comprises glass powder, >=95% of which passes through 100 μm mesh, or powder of its fired material, NaOH and a blowing agent. In the method for producing expanded granules, the diameter of the resulting expanded granules is <=30 mm and the mass of the granules per unit volume is 0.15-0.3 kg/l. Expanded granules obtained by the method are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to lightweight expansive particles and a method for preventing fusion during firing thereof, and more specifically, it is used as a lightweight aggregate for boards, a soil improving material, a heat insulating material for heat and cold insulation, an oil absorbing material, etc. This is a method for preventing fusion between expanded particles and their firing.

[0002]

2. Description of the Related Art Fusing is a phenomenon in which granules melt and stick to each other during firing in a kiln, or granules melt and stick to a furnace wall. Occurs when a smooth surface is formed. One means of preventing fusion is that a fusion preventing material having a melting point higher than that of the granulated material is present on the surface of the granulated material during firing. The unit volume mass of the granulated product before calcination is 0.9 to 1.0 kg / l, and the unit volume mass of the expanded particles of the present invention is 0.15 to 0.3 kg / l, that is, the diameter of each granulated product is about 1.5. In order to expand more than twice, it cannot be obtained without heating until it softens, and prevention of fusion is an indispensable means. As the anti-fusing material, fine powder of clay mineral can be used, and a typical example thereof is kaolin. In addition, even incinerated ash or the like can be used as long as it does not soften at the firing temperature.

To prevent fusion, for example, Japanese Patent Laid-Open No. 61-23
Japanese Patent Laid-Open No. 6621, Japanese Patent Laid-Open No. 57-88042 and Japanese Patent Laid-Open No. 57-92546 disclose a method of coating an anti-fusion material after granulation. But,
In this method, when the binder of the granulated product is water-soluble, the anti-fusing material absorbs the binder, resulting in a shortage of the binder, which hinders an increase in the firing temperature and a reduction in weight.

To prevent fusion, for example, Japanese Patent Laid-Open No. 4-
No. 310232, Japanese Patent Laid-Open No. 4-200740,
Japanese Unexamined Patent Publication (Kokai) No. 4-342483 discloses a method of coating a fusion preventing material after drying a granulated product. However, in this method, when the granulated product expands and a new surface is formed during firing, a shortage of the anti-fusing material occurs and fusion occurs.

In order to prevent fusion, for example, Japanese Patent No. 31
Japanese Patent No. 40473 discloses a method in which a fusion preventing material is added to a firing kiln together with a granulated material. However, in this method, since the granulated material having a different particle size and the anti-fusing material move differently in the kiln, a large amount of the anti-fusing material needs to be added and dust is often scattered. Further, since the anti-fusing material uses fine powder, it tends to settle on the kiln wall and hinders smooth movement of the granulated material.

Further, in order to prevent fusion, the above-mentioned patent publication discloses a method of transporting and adding a fusion preventing material to the burning point of the firing kiln. However, this method requires high-temperature-resistant transfer equipment, and in the case of air transfer, there is a large loss of thermal energy due to air blowing.

[0007]

DISCLOSURE OF THE INVENTION The inventor of the present invention raises the firing temperature because the anti-fusion agent is present in the surface layer of the granulated material to prevent fusion during firing of the granulated material. It becomes possible and the expansion is advanced and the weight is reduced.
The amount of the anti-fusing material used is minimized to prevent the anti-fusing material from settling in the kiln and to secure a reproducible residence time of the granulated product to obtain lightweight expanded particles. Even if the granulation product is coated with the anti-fusion material, the anti-fusion material does not absorb the water-soluble binder in the granulation product. No treatment such as drying is required after coating the anti-fusing material. Does not hinder the observation of the inside of the furnace due to dust generation. Also, it does not impair the working environment. As a result of earnest research on the above five points, the present invention has been achieved.

[0008]

Therefore, according to the present invention, when a granulated product using a water-soluble binder is fired to form expanded particles, the anti-fusing material is rolled on the granulated product in a dry state. The method for producing expanded particles is characterized in that the expanded particles are coated by the above-mentioned method, and baked together with the anti-fusing material in an amount equal to or less than the amount of the anti-fusing material used for the coating. Further, it is the method for producing expanded particles as described above, wherein the granulated material comprises glass powder having 100% or more of 95% or more, or a powder of the burned material thereof, NaOH, and a foaming agent. Further, in the method for producing expanded particles described above, the expanded particles have a particle diameter of 30 mm or less and a unit volume mass of 0.15 to 0.3 kg / l. In addition, the expanded particles are obtained by the manufacturing method described above.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The glass or the fired product thereof according to the present invention includes natural glass such as pearlite, artificial glass such as soda lime glass, and pearlite obtained by firing pearlite.
Perlite or the like that is used in industry and discarded, and can be used as long as it is softened by firing at around 1000 ° C. Further, NaOH acts as a water-soluble binder and as a regulator of the softening temperature of glass. Therefore, it is necessary to consider the composition of the glass in the mixing ratio. Further, the foaming agent generates a gas around the softening temperature of the granulated material, and, for example, SiC can be used.

Further, the expanded particles obtained by the present invention are obtained by fixing most of the fusion-preventing material treated after firing to the surface layer.

[0011]

EXAMPLES Example 1 100% by weight of 100% pearlite powder having an average particle size of 50 μm, 100% by weight of pearlite powder, caustic soda solution (concentration 21.
4%) 23.3 parts by weight, 2 parts by weight of a foaming agent, and 1 part by weight of an oxidizing agent were combined to obtain a total of 126.6 parts by weight to obtain a mixture. The water content was 14.5%. This compound (250 kg) was put into a granulator (Mitsui Mining Co., Ltd. stirring granulator TM500 type), and 0.5 to 3 mm of pre-dried granules were obtained by the stirring effect. This was dried by open flame to a residual water content of 2% or less. Next, 30 Kg of the dried granules and 4 Kg of kaolin, which is an anti-fusing material, were put into a tilting-type concrete mixer having a capacity of 120 l, and coating was performed by rolling for 5 minutes at a peripheral speed of 0.6 m / s. Then, the coated granule 34
Kg and 2 Kg of kaolin, which is an anti-fusing material, are cut out from the respective quantitative feeders for 1 hour, and can be fired at the set temperature of the external heat type rotary kiln 1110 ° C. without the occurrence of fusion, and the unit volume mass is 0. Light expanded particles of 280 kg / l were obtained.

Example 2 100% by weight of 97% passed 100 μm, and 100 parts by weight of pearlite powder having an average particle diameter of 50 μm, a caustic soda solution (concentration: 17.
8%) 28.1 parts by weight, 2 parts by weight of silicon carbide powder as a foaming agent, and 1 part by weight of an oxidizer were put into an 8-cut pan mixer and mixed to obtain a mixture. 300 kg of this mixture was put into a pan pelletizer (diameter 1200 mm, depth 140 mm, inclination angle 55 °,
It was fed and granulated for 1 hour at a rotation speed of 10 rpm through a constant quantity feeder to obtain a raw granulated product having a size of 15 mm or less. Residual water content 2 through a rotary kiln drying furnace with direct heating of kerosene
% To a dry granulated product. 30 parts by weight of this dry granulated product and hydrous kaolin (average particle size by liquid phase sedimentation method is 5 μm
m) 2 parts by weight was put into a tilting concrete mixer, and the surface layer of the dried granulated product was coated with hydrous kaolin. Subsequently, granulated product 3 coated with hydrous kaolin
2 parts by weight were cut out with a first fixed quantity feeder, 2 parts by weight of hydrous kaolin were cut out with a second fixed quantity feeder, and both were calcined at a set temperature of an external heat type rotary kiln 1110 ° C. for 34 kg per hour to obtain expanded particles. It was The volumetric mass of the expanded particles was 0.265 kg / l.

COMPARATIVE EXAMPLE 1 100% by weight of 97% passed 100 μm, and 100 parts by weight of pearlite powder having an average particle diameter of 50 μm, caustic soda solution (concentration 21.
4%) 23.3 parts by weight, 2 parts by weight of a foaming agent, and 1 part by weight of an oxidizing agent were combined to obtain a total of 126.6 parts by weight to obtain a mixture. The water content was 14.5%. This compound (250 kg) was put into a granulator (Mitsui Mining Co., Ltd. stirring granulator TM500 type), and 0.5 to 3 mm of pre-dried granules were obtained by the stirring effect. 35 kg of the granulated product before drying and 4 kg of kaolin as an anti-fusing material were put into a tilting concrete mixer with a capacity of 120 l, and coated by rolling for 5 minutes at a peripheral speed of 0.6 m / s. This was dried by open flame to a residual water content of 2% or less. Subsequently, 34 Kg of the dried granules were cut out from the constant quantity feeder for 1 hour and fired at the set temperature of the external heating rotary kiln 1110 ° C., but some fusion was observed. The unit volume mass of the expanded particles was 0.310 kg / l.

Comparative Example 2 100% of 100% by weight passed through 100%, and 100 parts by weight of pearlite powder having an average particle diameter of 50 μm, caustic soda solution (concentration 21.
4%) 23.3 parts by weight, 2 parts by weight of a foaming agent, and 1 part by weight of an oxidizing agent were combined to obtain a total of 126.6 parts by weight to obtain a mixture. The water content was 14.5%. This compound (250 kg) was put into a granulator (Mitsui Mining Co., Ltd. stirring granulator TM500 type), and 0.5 to 3 mm of pre-dried granules were obtained by the stirring effect. This was dried by open flame to a residual water content of 2% or less. 30 kg of this dry granulated product and 4 kg of kaolin as a fusion preventing material were put into a tilting concrete mixer with a capacity of 120 l, and coated by rolling for 5 minutes at a peripheral speed of 0.6 m / s. 34 kg of this coated granule,
It was cut out from the constant quantity feeder for 1 hour and fired at the set temperature of the external heat type rotary kiln 1110 ° C.
Since fusion occurred, the set temperature was set to 1090 ° C, and the unit volume mass of the obtained expanded particles was 0.300 kg.
It was / l.

Comparative Example 3 100% of pearlite powder having an average particle size of 50 μm and 100% of which passed through 100 μm, caustic soda solution (concentration 21.
4%) 23.3 parts by weight, 2 parts by weight of a foaming agent, and 1 part by weight of an oxidizing agent were combined to obtain a total of 126.6 parts by weight to obtain a mixture. The water content was 14.5%. 250 kg of this blend was put into a granulator (Mitsui Mining Co., Ltd. stirring granulator TM500 type), and 0.5 to 3 mm of pre-dried granules were obtained by the stirring effect. This was dried by open flame to a residual water content of 2% or less. 30 kg of this dry granulated product and 4 kg of kaolin as a fusion preventing material were put into a tilting concrete mixer with a capacity of 120 l, and coated by rolling for 5 minutes at a peripheral speed of 0.6 m / s. 34 kg of this coated granule,
It was cut out from the constant quantity feeder for 1 hour and fired at the set temperature of the external heat type rotary kiln 1110 ° C.
Fusion occurred. For this reason, the dried granulated product is 30 kg again.
And 6 kg of kaolin, which is an anti-fusing material, from a constant quantity feeder
Cut out over time. However, the uneven distribution of kaolin increased the tendency to obstruct the flow of the granules with the passage of time in the rotary kiln. The unit volume mass was 0.280 kg / l in the initial stage at the set temperature of the external heat type rotary kiln 1110 ° C, but was 0.300 k in the latter stage.
It became heavy with g / l.

Comparative Example 4 100% by weight of 97% passed 100 μm and an average particle diameter of 50 μm, 100 parts by weight of pearlite powder, caustic soda solution (concentration 21.
4%) 23.3 parts by weight, 2 parts by weight of a foaming agent, and 1 part by weight of an oxidizing agent were combined to obtain a total of 126.6 parts by weight to obtain a mixture. The water content was 14.5%. 250 kg of this blend was put into a granulator (Mitsui Mining Co., Ltd. stirring granulator TM500 type), and 0.5 to 3 mm of pre-dried granules were obtained by the stirring effect. This was dried by open flame to a residual water content of 2% or less. 30 kg of this dried granulated product was cut out from the constant quantity feeder for 1 hour, and at the same time, 8 kg of kaolin was blown by compressed air to the highest temperature point in the external heating type rotary kiln per hour. Dust was so strong that the fusion state inside the kiln could not be visually observed, and there were many spouts outside the furnace, which hindered operation.

Comparative Example 5 81% of the particles passed 250 μm and the average particle size was 150 μm.
100 parts by weight of pearlite powder, caustic soda solution (concentration 1
7.8%), 28.1 parts by weight, 2 parts by weight of silicon carbide powder as a foaming material, and 1 part by weight of an oxidizer were put into an 8-section pan mixer and mixed to obtain a mixture. 300 kg of this mixture was put into a pan pelletizer (diameter 1200 mm, depth 140 mm, inclination angle 55).
The granules were fed and granulated for 1 hour at a rotation speed of 10 rpm through a constant quantity feeder to obtain raw granules of 15 mm or less. Subsequently, it was passed through a rotary kiln drying furnace of direct heating with kerosene to obtain a dry granulated product having a residual water content of 2% or less. 30 parts by weight of this dry granulated product and hydrous kaolin (average particle size by liquid phase sedimentation method is 5
(μm) 2 parts by weight was added to a tilting concrete mixer, and the surface layer of the dried granulated product was coated with hydrous kaolin. Subsequently, 32 parts by weight of the granulated product coated with hydrous kaolin was cut out with a first fixed amount feeder, 2 parts by weight of hydrous kaolin was cut out with a second fixed amount feeder, and both were set at an external heating rotary kiln 1110 ° C. In the above, 34 Kg per hour was calcined to obtain expanded particles. The volumetric mass of the expanded particles was 0.325 kg / l.

[0018]

EFFECTS OF THE INVENTION A lightweight foam is efficiently manufactured without fusion bonding.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C04B 20/00 C04B 20/00 B 38/02 38/02 K 38/08 38/08 B C09C 3/00 C09C 3/00 (72) Inventor Koichi Muroya 1-1-11 Osaki, Shinagawa-ku, Tokyo Mitsui Kinzoku Mining Co., Ltd. Perlite Division F-term (reference) 4G004 AA01 BA00 PA01 4G019 JA02 LA01 LB02 LC11 LD02 4G066 AA13D AA63D AA67A AA67B AA71A AA71B AA72D BA20 BA38 CA05 FA22 FA26 FA37 4J037 AA08 AA17 AA29 CA25 DD05 DD06 DD11 EE03 EE26 EE44

Claims (4)

[Claims] 1. When a granulated product using a water-soluble binder is fired to form expanded particles, the granulated product is coated with a fusion preventing material by rolling in a dry state, and the melt used in the coating is applied. A method for producing expanded particles, which comprises firing with an anti-fusing material in an amount equal to or less than the amount of anti-adhesion material. 2. The method for producing expanded particles according to claim 1, wherein the granulated product is composed of glass powder or 95% or more of glass powder that passes through 100 μm, powder of the fired product, NaOH, and a foaming agent. 3. The method for producing expanded particles according to claim 2, wherein the expanded particles have a particle diameter of 30 mm or less and a unit volume mass of 0.15 to 0.3 kg / l. 4. Expanded particles obtained by the manufacturing method according to claim 1.