JPH0474776A - Production of light inorganic molded material - Google Patents

Abstract

PURPOSE:To obtain an inorganic molded material having light weight and excellent mechanical strength and resistance to water in a low cost by mixing metallic silicon (alloy) and cement into an alkali silicate aqueous solution, foaming, molding and hardening. CONSTITUTION:100 pts.wt. (A) an alkali silicate aqueous solution (preferably aqueous solution of sodium silicate containing about 2.0:1-3.7:1 molar ratio of SiO2:Na2O) is mixed with 40-70 pts.wt., preferably 55-65 pts.wt. (B) metallic silicon or alloy of said silicon and (C) cement in an amount of 0.1-15 wt.%, preferably 2-8 wt.% to the total amount of the components A and B, then molded with foaming, thus hardened to afford an inorganic molded material having light weight. Besides, granular inorganic foaming material such as perlite is able to be mixed as a component other than the components A-C, as necessary. In said case, mixing amount of the material is <=40 wt.%, preferably about 5-30 wt.% of total weight of molded material.

Description

[Detailed description of the invention] The present invention relates to a method for producing a lightweight inorganic molded body.

Conventionally, a lightweight inorganic molded body made by hardening a granular inorganic foam such as pearlite with an alkali silicate binder has been proposed (Japanese Patent Application Laid-open No. 7681/1983).

However, the molded product obtained by the above method has poor mechanical strength and water resistance because the binder used itself has poor mechanical strength and water resistance. Moreover, there are inherent restrictions on the amount of binder used, and only a small amount of 30 to 120 parts by weight can be used per 100 parts by weight of the inorganic foam, so it is difficult to modify the binder to increase its strength. . In addition, in the above method, it is necessary to use a large amount of pearlite made of foamed pearlite, obsidian, etc., but these have problems such as being expensive and difficult to obtain in large quantities.

In addition, an inorganic molded product made by curing an inorganic foam such as pearlite using cement as a hardening agent has been proposed, but such a molded product has the drawback that although it can improve strength, it greatly reduces its lightness.

In contrast, the present invention aims to provide a method for producing a lightweight inorganic molded body that has excellent mechanical strength and water resistance over time.

That is, the present invention involves mixing a) an aqueous alkali silicate solution, b) metallic silicon or its alloy, and C) cement in an amount of 0.1 to 15% by weight based on the total amount of a) and b) above, and forming the mixture while foaming. The present invention relates to a method for producing a lightweight inorganic molded body, which is characterized by curing.

It is well known that when an aqueous alkali silicate solution is mixed with metal silicon or its alloy, it hardens while generating hydrogen gas and a hardened foam is obtained. However, the hardened foam obtained has poor compressive strength and is brittle. It was just that. However, according to the research of the present inventor, when cement is present in a specific amount of 0.1 to 15% by weight based on the total weight of the two components in the above-mentioned reaction system of the two components, the cement undergoes the foaming and hardening reaction of the two components. It has been discovered that by working well with these components without inhibiting the properties of the foam, a cured foam product having significantly superior mechanical strength and water resistance can be obtained. The reason why such a remarkable effect can be obtained by mixing a small amount of cement is still unclear. It is assumed that this is a result of involvement in the reaction itself.

In the present invention, the aqueous alkali silicate solution used as component a) includes an aqueous solution of sodium silicate or potassium silicate. Particularly preferred is SiO2/Na2O
It is an aqueous sodium silicate solution with a molar ratio of about 2.0:1 to 3.7:1. As the aqueous alkali silicate solution, either one that can be prepared manually as a single substance or one that can be obtained as water glass can be used.

Metal silicon or its alloy used as component b) includes metal silicon, a mixture of metal silicon and silicon dioxide, and an Fe-8i alloy such as ferrosilicon.

Among these, ferrosilicon is particularly preferred. It is preferable to use the metal silicon or its alloy in the form of a fine powder, and it is particularly preferable to use one having a mesh size of 1,000 to 2,000.

The aqueous alkali silicate solution and metallic silicon or its alloy are blended in such a proportion that the two react, generate hydrogen gas, and harden to give a foamed hardened product. Such a blending ratio is known in this technical field, and can be applied to all known blending ratios, but in particular, an aqueous alkali silicate solution of 10%
It is preferable to mix metal silicon or its alloy in a ratio of 40 to 70 parts by weight, particularly preferably 55 to 65 parts by weight, based on 0 parts by weight.

Further, as the cement used in the present invention, various types of cement can be used, but Portland cement is the most preferable. The amount of cement blended is 0.1 to 15% by weight based on the total weight of the aqueous alkali silicate solution and metal silicon or its alloy.
It is essential that the Cement content is 0
．． If the amount is less than 1% by weight, the resulting foamed molded product will be poor in strength and water resistance. On the other hand, 15% by weight
If the amount is exceeded, the foaming reaction will be inhibited, making it impossible to obtain a lightweight molded product. A particularly preferred amount of cement is in the range of about 2 to 8% by weight based on the total weight of the aqueous alkali silicate solution and metal silicon or its alloy.

In the present invention, in addition to the above three components, various additives may be added as necessary. For example, in order to further promote weight reduction, granular inorganic foams such as pearlite or obsidian foams or shirasu balloons may be blended. In this case, if the amount of the inorganic foam is too large, the strength of the resulting molded product will be reduced, so it is preferably 40% by weight or less, preferably 5 to 30% by weight, based on the total weight of the molded product. In addition, other inorganic reinforcing materials such as glass fibers and steel fibers may be added as required.

The molded article of the present invention is obtained by uniformly stirring the above-mentioned three-component mixture of a), b) and C), or a mixture containing additives as necessary, and molding and curing it while foaming. When the three components are stirred, foaming occurs within a few minutes, generating heat and generating hydrogen gas. Therefore, if you pour it into an appropriate mold while it is fluid even before or after gas generation,
Foaming progresses and bulk increases, moisture evaporates and viscosity is lost, and the compound hardens rapidly. In this way, the lightweight inorganic molded article of the present invention is obtained. The time required during this period is usually only a few minutes to about an hour. Therefore, the desired inorganic molded body can be obtained in an extremely short time and with simple operations.

The molded product obtained according to the present invention is a lightweight inorganic molded product having a cellular structure composed of a large number of cells and a skeleton that surrounds the cells and has a large compressive strength. The skeleton surrounding the bubbles is formed from a hard and strong material produced by the reaction or interaction of the three components mentioned above, and as a result, the molded product obtained by the present invention is not only lightweight due to the presence of a large number of bubbles, but also can be easily used in large machines. It has physical strength and water resistance. Furthermore, since it is made of inorganic material, it is nonflammable and fire resistant. An inorganic molded body containing a granular inorganic foam such as perlite has the foam dispersed therein, resulting in a lighter molded body.

Therefore, by utilizing these properties, the molded article of the present invention can be used as lightweight heat insulating materials, lightweight heat insulating materials, lightweight fireproof materials, e-sound materials, etc., and building materials such as flooring materials, wall materials, ceiling materials, partition materials, etc. It can be widely used as

Example The present invention will be explained in more detail with reference to Examples below.

Examples 1 to 4 and Comparative Example 1 Ferrosilicon and cement are thoroughly stirred in a container according to the formulation shown in Table 1 below, and aggregates such as perlite are added as needed. After thorough stirring, the prescribed silicate soda is added. Pour into this mixed material and knead again. Since the reaction begins at the same time as kneading, the mixture is quickly kneaded in a short period of time, and the mixed material is poured into a pre-made mold. After injection, the volume of this mixture gradually increases, and after about 15 minutes, the reaction accelerates, hydrogen gas and water vapor are ejected, and curing begins.
After a few seconds, a foam molded product will be completed. In order to measure the quality of this foam molded product, a 30 cm square block was made, and after drying and cooling to room temperature, it was made into a 10 cm x 10 cm x block for measurement.
It was processed into a 10 cm molded body. The quality was measured by applying the standard of lightweight aerated concrete panel JIS A 5416. The results are also listed in Table 1.

Claims (1)

[Claims] (1) Mix a) aqueous alkali silicate solution, b) metallic silicon or its alloy, and c) cement in an amount of 0.1 to 15% by weight based on the total amount of a) and b) above, and mold and harden while foaming. A method for producing a lightweight inorganic molded body. (2) Above a), b)
The method for producing a lightweight inorganic molded article according to claim 1, wherein 30% by weight or less of the granular inorganic foam is mixed with the components and c) and molded and hardened while foaming.