JPH0723243B2 - Method for producing cured inorganic material - Google Patents

Description

TECHNICAL FIELD The present invention relates to the production of an inorganic cured product. More specifically, the present invention relates to a method for producing a cured inorganic material having excellent heat shrinkage resistance.

[Conventional technology and problems]

Hardened products obtained by the reaction of siliceous raw materials and calcareous raw materials mainly include hardened cement and hardened calcium silicate, but these have a problem in heat resistance at high temperatures, and in particular, residual shrinkage by heating. Therefore, there is a drawback that the cured product is apt to crack or deform due to heating.

Therefore, in order to improve this point, at present, in order to produce a cured product to be used for a member that requires heat resistance at high temperatures, it is necessary to use raw materials that have been carefully selected, or to perform long-term curing under high temperature and high pressure. It is carried out, or means such as adding heat-resistant aggregates such as asbestos, mica, wollastonite, etc. is used. However, when such a method is adopted, not only a large cost is required in terms of energy and raw materials for producing a cured product, but also when a large amount of heat-resistant aggregate is used, mixing, molding, There are many troubles in the manufacturing process such as curing, and the product surface may be defective.

Therefore, the present invention is intended to improve the heat shrinkage resistance of the cured product obtained by the reaction of the siliceous raw material and the calcareous raw material by a conventional method.

[Means for Solving the Problems]

That is, in the present invention, the total of siliceous raw material and calcareous raw material is 10
0 parts by weight, 5 to 100 parts by weight of calcium carbonate and 0.2 to 8 parts by weight of a chloride of an alkali or alkaline earth metal are used as main raw materials, and curing is carried out after molding.
The present invention provides a method for producing an inorganic cured body.

The siliceous raw material and calcium raw material used in the present invention are
Commonly used silica sand, fly ash, diatomaceous earth, amorphous silica, slag, cement, slaked lime, quick lime and the like are mentioned, but not particularly limited. The ratio of the siliceous raw material to the calcium raw material is also selected according to the intended means such as curing conditions and strength of the cured product, and is not limited. 5 to 100 parts by weight of calcium carbonate and 0.2 to 8 parts by weight of alkali or alkaline earth metal chloride are added to a total of 100 parts by weight of these siliceous materials and calcium materials.

It is surprising that only one of calcium carbonate and chloride has little effect, and when both are added together, excellent heat resistance can be obtained.

The type of chloride used is preferably an alkali or alkaline earth metal chloride, more preferably potassium chloride, sodium chloride, calcium chloride, barium chloride or the like.

When the amount of calcium carbonate is 5 parts by weight or less, the heat resistance improving effect cannot be obtained, and when it is 100 parts by weight or more, the strength of the molded body is largely decreased, which is not preferable. Further, if the amount of chloride added is 0.2 parts by weight or less, no effect is recognized, and even if 8 parts by weight or more is added, further improvement of the effect cannot be expected. Suitable amounts of both are 20 to 40 parts by weight of calcium carbonate and 1 to 3 parts by weight of chloride.

In the production of these inorganic cured products, it is possible to add a fibrous raw material as a reinforcing aid, and the types thereof include glass fiber, organic synthetic fiber, cellulose pulp fiber, carbon fiber and the like. To be If necessary, aggregate (perlite, shirasu balloon, crushed pumice stone,
The mechanical properties and specific gravity of the cured inorganic material can be adjusted by adding sand or the like).

On the other hand, depending on the molding method, a molding aid can be added as necessary. As an example, a thickening agent in the extrusion method,
Examples include water reducing agents and superplasticizers in the casting method.

As a method for molding the cured body, a molding method generally used for molding an inorganic cured body, such as a papermaking method, a press molding method, an extrusion molding method, a casting method, and a spray suction method, can be applied. Generally, in the papermaking method, the raw material is dispersed with a large amount of water to form a slurry, and the slurry is passed over a net to obtain a molded body, but the chloride added at this time escapes into the liquid, and the effect of the present invention. However, in the present invention, the effect of chloride addition is not lost even if it is slightly weakened in the present invention. The reason for this is that chloride is adsorbed or reacted with the raw material added together, and is fixed, so that the escape to the liquid is expected to be relatively small. It should be noted that, in extrusion molding methods, casting methods such as casting methods that do not generate superfluous water, chloride escape does not occur at all,
This is a preferable molding method for sufficiently exhibiting the effects of the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples.

〔Example〕

Raw materials were blended in proportions shown in Table 1 for each of the cement-based, calcium silicate-based, and cement + amorphous silica-based systems. Formulation Nos. 1, 5, and 9 in Table 1 are examples, and other numbers are comparative examples.

(Molding method) Each raw material of Table 1 was put into 5 times the fresh solid water,
After stirring well to make a slurry, it was passed and the remaining cake was molded at a pressing pressure of 100 kg / cm ² to obtain a plate of 80 × 150 × 10 mm. Next, each system was cured and cured under the conditions shown in Table 1.

(Heat shrinkage resistance test) The obtained test piece was dried in a 105 ° C dryer for 24 hours to give a diameter of 5
It was cut into a cylinder of mm × 20 mm, and the thermal expansion / contraction ratio was measured. The results are shown in FIGS. 1, 2 and 3.

As can be seen from the results of FIG. 1, FIG. 2 and FIG. 3, in any of the cement type, calcium silicate type and cement + amorphous silica type systems, compared to the sample in which neither calcium carbonate nor potassium chloride was added. In some of the samples to which either one of them is added, the shrinkage due to heating has a slight effect of reducing the shrinkage rate, but the degree is small or the shrinkage becomes large. On the other hand, according to the present invention, in the case of a sample to which both calcium carbonate and potassium chloride are added, shrinkage due to heating is greatly improved.

〔The invention's effect〕

In the production of an inorganic hardened body obtained by the reaction of a siliceous raw material and a calcium based raw material, by adding inexpensive calcium carbonate and chloride, it is possible to obtain a molded body having excellent heat resistance. This eliminates the need for aggregates of heat-resistant fibers such as asbestos, which has been used in the past, and does not require much energy. Therefore, it is possible to manufacture a cured product with excellent heat resistance at low cost by the usual method. It is what This inorganic cured material can be widely applied to materials that require heat resistance, such as building structures and building materials.

[Brief description of drawings]

FIG. 1 is a diagram showing a heat shrinkage rate of a cement-based inorganic cured product. FIG. 2 is a diagram showing a heat shrinkage rate of a calcium silicate-based inorganic cured product. FIG. 3 is a diagram showing a heat shrinkage rate of cement + amorphous silica-based inorganic cured material. In each figure, the vertical axis represents the thermal expansion / contraction rate, and the horizontal axis represents the heating temperature.

Claims (3)

[Claims] 1. A total of 100 parts by weight of a siliceous raw material and a calcareous raw material, 5 to 100 parts by weight of calcium carbonate and 0.2 to 8 parts by weight of a chloride of an alkali or alkaline earth metal as a main raw material, and curing is performed after forming. A method for producing a cured inorganic material, comprising: 2. The method according to claim 1, wherein the alkali or alkaline earth metal is potassium chloride, calcium chloride, sodium chloride or barium chloride. 3. The manufacturing method according to claim 1, wherein the molding is performed by an extrusion molding method or a casting molding method.