JPH0155215B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is applicable to high-temperature environments of 1000°C or higher
This article relates to lightweight fireproof structural materials that are lightweight and have excellent heat insulation and volumetric stability. [Prior Art] Generally known lightweight fireproof structural materials include diatomaceous earth bricks, castable refractories made of alumina cement mixed with lightweight aggregate, and aerated concrete. However, in an atmosphere of 1000℃ or higher, especially 1500℃ or higher, diatomaceous earth bricks lack heat resistance and fire resistance, and castable refractories, even though they have sufficient fire resistance, lack heat resistance and have a bulk specific gravity of 1g/ It was heavy, over cm ³ . Aerated concrete was difficult to use due to explosion and melting. [Problems to be solved by the invention] The present inventors have developed a lightweight fire-resistant structural material that is lightweight, has excellent heat insulation properties and volumetric stability, and has good workability in high-temperature atmospheres of 1000°C or higher, particularly 1500°C or higher. As a result of various studies regarding this, it was discovered that it is sufficient to mix fine powder refractory aggregate and air bubbles with alumina cement of a specific composition to increase the overall porosity to 50% or more, thus completing the present invention. [Means for Solving the Problems] That is, the present invention provides a composite material comprising an alumina cement hydrate, a fine powder refractory aggregate with a maximum particle size of 1 mm or less and an average particle size of 88 μ or less, and air bubbles with a diameter of 3 mm or less. The alumina cement hydrate is a hardened product with a porosity of 50% or more, and contains 50 to 70 parts by weight of CaO.Al ₂ O ₃ , 10 to 40 parts by weight of 12CaO.7Al ₂ O ₃ , and 10 to 40 parts by weight of CaO.
A lightweight fire-resistant structural material characterized by being a hydrate of alumina cement consisting of 0 to 50 parts by weight of 2Al ₂ O ₃ and 0 to 60 parts by weight of amorphous material. The present invention will be explained in more detail below. The alumina cement used in the present invention is CaO・
Al ₂ O ₃ 50 to 70 parts by weight, 12CaO・7Al ₂ O ₃ 10 to 40 parts by weight, CaO・2Al ₂ O ₃ 0 to 50 parts by weight, and amorphous 0 to 60
If you use alumina cement other than this, the strength and fire resistance at high temperatures will decrease. The fine powder refractory aggregate is preferably one that exhibits little volumetric expansion or contraction due to thermal changes, such as α-Al 2 O 3 , α-Al ₂ O ₃ ,
MgO・Al ₂ O ₃ , 3Al ₂ O ₃・2SiO ₂ , SiO ₂ and Cr ₂ O ₃
etc. can be used. The particle size structure is such that the maximum particle size is 1 mm or less and the average particle size is 88 μm or less. Outside of this, the insulation is poor, the bulk specific gravity becomes large, and cracks occur due to expansion and contraction due to thermal changes. The bubble has a diameter of 3 mm or less,
If it is larger than that, the heat insulation properties and strength will decrease. The amount of bubbles is such that the porosity is 50% or more, and if it is less than 50%, the insulation properties will be poor. The method for incorporating air bubbles is as follows: (1) Add and mix a predetermined amount of combustible material into alumina cement and/or finely powdered refractory aggregate, add water to form a slurry, harden it, and heat it to remove the combustible material. Method (2): Add water to a mixture with alumina cement and/or fine refractory aggregate to form a slurry, add a foaming agent or foaming agent, and then harden. Flammable materials include plastic,
Examples include cellulose and charcoal, while foaming agents or foaming agents include albumin, B vitamins,
Examples include foaming agents such as protein-based foaming agents such as amylase, metal powders, and alkali metal salts. Protein-based foaming agents are preferred from the viewpoint of ease of controlling the size and amount of pores. Foaming methods include mechanical methods such as shaking, stirring, and air supply, physical methods such as solubility reduction, and heating.
There are chemical methods such as heating carbonate, adding acid, and fermentation (``Foam Trouble and Defoaming Technology'' published by Hyogo Management Development Center Publishing Department, October 1, 1988). Note that the bubbles are preferably closed cells. A normal mortar mixer is sufficient for mixing the above alumina cement, fine powder refractory aggregate, and air bubbles, and curing after forming is performed in water, air drying, steam, high temperature and high pressure, or a combination thereof. [Example] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. CaO・Al ₂ O ₃ , 12CaO・7Al ₂ O ₃ , CaO・2Al ₂ O ₃
After adding and mixing the amorphous alumina cement shown in Table 1 and fine powder refractory aggregate, water was added to form a slurry. A predetermined amount of air bubbles with a particle size of 3 mm or less (the amount of the mixture is shown in Table 2) is added to this slurry, and the mixture is uniformly dispersed.
After curing, lightweight fireproof structural materials shown in Table 3 were obtained. The physical properties were measured by the following method. Bulk specific gravity: According to JIS R2614, after drying at 400°C, it was allowed to cool to room temperature and the weight per volume was measured. Porosity: According to JIS R2205. Thermal conductivity: According to JIS R2618. Linear change rate: According to JIS R2554, the residual linear expansion coefficient was measured before and after firing at 1600°C. Strength: In accordance with JIS R2521, the strength was measured after firing at 1200°C for 3 hours. Fire resistance: Conforms to JIS R2573.

【table】

【table】

[Table] Examples of different rates.

【table】

〔Effect of the invention〕

The lightweight fireproof structure of the present invention is particularly suitable for temperatures above 1000°C.
In high temperature atmospheres of 1500℃ or higher, it is lightweight, has excellent heat insulation and volume stability, and is easy to process, so it is suitable for use as heat insulating materials, sound insulating materials, etc. If used as a fireproof structural material, it will have extremely good effects.
Furthermore, since it has good heat insulation properties, energy saving can be made more efficient.

Claims (1)

[Claims] 1 Alumina cement hydrate, fine powder refractory aggregate with a maximum particle size of 1 mm or less and an average particle size of 88 μ or less, and diameter 3
The alumina cement hydrate is a hardened material containing air bubbles of mm or less and having a total porosity of 50% or more,
CaO・Al ₂ O ₃ 50~70 parts by weight, 12CaO・7Al ₂ O ₃ 10~
A lightweight fireproof structural material characterized by being a hydrate of alumina cement consisting of 40 parts by weight, 0 to 50 parts by weight of CaO.2Al ₂ O ₃ and 0 to 60 parts by weight of amorphous.