JPH0297444A - Production of inorganic hardened body - Google Patents

Abstract

PURPOSE:To improve the heat resistance of an inorg. hardened body produced by bringing siliceous and calcic starting materials into a reaction by adding specified amts. of calcium carbonate and an alkali metal or alkaline earth metal chloride to the starting materials. CONSTITUTION:100 pts.wt., in total, of siliceous and calcic starting materials, 5-100 pts.wt. calcium carbonate and 0.2-8 pts.wt. alkali metal or alkaline earth metal chloride are used as principal starting materials. These starting materials are brought into a reaction and cured to obtain an inorg. hardened body. By this method, the hardened body having superior heat resistance is obtd. without requiring heat resistant fibers such as asbestos as aggregate or consuming much energy. In case of <5 pts.wt. CaCO3, a heat resistance improving effect is not produced. In case of >100 pts.wt. CaCO3, the strength of the hardened body is considerably lowered. When the amt. of the chloride is <0.2 pt.wt., the effect is not produced. Even when the chloride is added by >8 pts.wt., the effect is not further enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to the production of an inorganic cured body. More specifically, the present invention relates to a method for producing an inorganic cured product having excellent heat shrinkage resistance.

[Conventional technology and issues]

Hardened products obtained by the reaction of silicic raw materials and calcareous raw materials mainly include hardened cement products and hardened calcium silicate products, but these have problems in heat resistance at high temperatures, especially in terms of residual shrinkage after heating. Because of the large amount of heat, cracks and deformation easily occur in the cured product due to heating.

In order to improve this point, currently, in order to manufacture cured products used in parts that require heat resistance at high temperatures, it is necessary to use sufficiently refined raw materials, or to cure them for long periods of time under high temperature and high pressure. or asbestos, mica,
Measures such as adding heat-resistant aggregates such as wollastonite are being used. However, when using such a method, not only is a large amount of cost required in terms of energy and raw materials to manufacture the hardened product, but also when a large amount of heat-resistant aggregate is used, mixing, molding, During the manufacturing process such as curing, 1 to 1 to 10 rubs may increase, and defects may occur on the surface of the product.

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

[Means to solve the problem]

That is, in the present invention, the total of the siliceous raw material and the calcareous raw material is 1
00 parts by weight, 5 to 100 parts by weight of calcium carbonate, and 0.2 to 8 parts by weight of an alkali or alkaline earth metal chloride as main raw materials, which is characterized by curing and curing after molding. This is what we provide.

The siliceous raw materials and calcium raw materials used in the present invention are:
Commonly used materials include silica sand, fly ash, diatomaceous earth, amorphous silica, slag, cement, slaked lime, and quicklime, but are not particularly limited. Furthermore, the ratio of the silicic acid raw material to the calcium raw material is not limited, as it depends on the curing conditions, the strength of the cured product, and other objectives. A total of 100 parts by weight of these silicic raw materials and calcium raw materials, 5 to 100 parts by weight of calcium carbonate, and 0.2 to 8 parts of alkali or alkaline earth metal chloride.
Combine the heavy parts and add.

Calcium carbonate and chloride have little effect when used alone, and it is surprising that by adding both together, excellent heat resistance can be obtained.

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

If the amount of calcium carbonate is less than 5 parts by weight, no effect of improving heat resistance can be obtained, and if it is more than 100 parts by weight, the strength of the molded product will be greatly reduced, which is not preferable. Further, the amount of chloride added is 0.
No effect is observed when the amount is less than 2 parts by weight, and no further improvement in the effect can be expected even when more than 8 parts by weight is added. Suitable amounts of both include 20 to 40 parts by weight of calcium carbonate and 1 to 40 parts by weight of chloride.
It is 3 parts by weight.

When producing these inorganic cured products, it is also possible to add fibrous raw materials as reinforcing aids, examples of which include glass fiber, organic synthetic fiber, cellulose bulb fiber, carbon U1 fiber, etc. Can be mentioned. Furthermore, if necessary, the mechanical properties and specific gravity of the inorganic cured product can be adjusted by adding aggregate (perlite, shirasu balloons, crushed pumice, sand, etc.).

On the other hand, depending on the molding method, a molding aid may be added as necessary. For example, thickeners in extrusion processes,
Examples include water reducing agents and fluidizing agents in the casting method.

As a method for molding the cured product, a molding method used for molding an inorganic cured product into -ffi, such as a papermaking method, a press molding method, an extrusion method, a casting method, and a spray suction method, can be applied.

In the shell papermaking method, raw materials are dispersed in a large amount of water to form a slurry, and then the slurry is filtered through a mesh to obtain a molded product.
There seems to be a risk that the chloride added at this time escapes into the P solution and loses the effect of the present invention, but in the present invention, even with such a papermaking method, the effect of adding chloride is
Even if it is slightly interrupted, it will never be lost. The reason for this is that chloride also adsorbs or reacts with 1 and is fixed, so the escape to the P solution is expected to be relatively small. Note that molding methods that do not generate filtrate water, such as extrusion molding and casting, do not allow chloride to escape at all, and are therefore suitable molding methods for fully demonstrating the effects of the present invention.

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

〔Example〕

Raw materials were blended in the proportions shown in Table 1 for three systems: cement system, calcium silicate system, and cement 1-amorphous silica system. Blend No. in Table 1: 1.5
, and 9 are examples, and the other Nos. are comparative examples.

(Forming method) Each raw material in Table 1 was poured into clean water with an amount of 5 times the total solid weight,
After stirring well and making a slurry, it was filtered, and the remaining cake was molded at a press pressure of 100 ky/cI112.
It was made into a plate-like body of 0x150x10zz. Next, each prefecture was cured and hardened under the conditions shown in Table 1.

(Heat shrinkage resistance test) The obtained test piece was dried in a dryer at 105°C for 24 hours.
It was cut into a cylindrical shape with a diameter of 531RX20JFll, and the thermal expansion and contraction rates were measured. The results are shown in FIGS. 1, 2 and 3.

Table 1 As can be seen from the results in Figures 1, 2, and 3, both calcium carbonate and potassium chloride were added to the seven-mention system, calcium silicate system, and cementitious amorphous silica system. Compared to the sample [1] without the addition of either of the two, the shrinkage caused by heating shows a slight reduction in the shrinkage rate, but the degree of shrinkage is small or the shrinkage becomes large. On the other hand, according to the present invention, in the case of samples to which both calcium carbonate and potassium chloride are added, heating is performed! 15! Shrinkage is greatly improved.

〔Effect of the invention〕

In gJ production of an inorganic hardened body obtained by the reaction of silicate raw material [1] and calcium raw material, a molded body with excellent heat resistance can be obtained by adding inexpensive calcium carbonate and chloride. This eliminates the need for aggregates of heat-resistant fibers such as asbestos, which were conventionally used, and also does not require much energy, making it possible to produce cured products with excellent heat resistance at low cost using normal methods. It is possible.

This inorganic hardened material is used for construction materials, construction materials, etc.
It can be widely applied to materials that require heat resistance.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the heat shrinkage rate of a cement-based inorganic cured product. FIG. 2 is a diagram showing the heat shrinkage rate of a calcium silicate-based inorganic cured product. FIG. 3 is a diagram showing the heat shrinkage rate of an inorganic cured product of cement and amorphous silica. In each figure, the vertical axis shows the heating expansion/contraction rate, and the horizontal axis shows the heating temperature. Representative Patent Attorney Teru Sogado:',','・
·cormorant

Claims (3)

[Claims] (1) The total amount of siliceous raw material and calcareous raw material is 100 parts by weight,
A method for producing an inorganic cured body, which uses 5 to 100 parts by weight of calcium carbonate and 0.2 to 8 parts by weight of an alkali or alkaline earth metal chloride as main raw materials, and which is characterized by curing and curing after molding. (2) The manufacturing 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.