JPS586706B2 - Method for producing calcium silicate hydrate molded body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for producing a calcium silicate hydrate molded article.

Calcium silicate hydrate molded bodies are used, for example, as architectural panels, columns, and U-shaped bodies.

Conventionally, these molded bodies are made using slaked lime powder and cemento as the calcareous raw materials, and one or more of powdered silica stone, diatomite, and silica sand as the silicate raw materials, and these are blended to form an aqueous slurry. It was manufactured by molding according to a method followed by curing with high temperature and high pressure steam.

However, although the products manufactured in this way have good formability, the formation of tobermolite, which is a desirable crystal structure as a crystal product after steam curing treatment, is hardly observed, and as a result, It had a large wet-dry shrinkage rate, low compressive strength, low bending strength, and other drawbacks, such as easy shrinkage due to carbonation caused by carbon dioxide gas in the atmosphere.

An object of the present invention is to provide a method for producing a calcium silicate hydrate molded article that eliminates the above-mentioned drawbacks.

In order to achieve the above object, the method of the present invention uses quicklime instead of the conventionally used slaked lime as the main raw material, and it requires leaving the prepared slurry in the air for more than one hour before molding. and the main raw materials CaO/SiO.

It is novel in that the weight ratio and cement/quicklime weight ratio are regulated.

That is, the method of the present invention uses quicklime and cement as calcareous raw materials, which are the main raw materials, powdered silica stone as silicic raw materials,
Silica sand, one or more of the ten diatoms, and the mixing ratio is CaO
The weight ratio of /SiO2 was adjusted to 0.2 to 1.5, and the weight ratio of cement/quicklime was adjusted to 1 to 20. Add water and stir to mix to form a slurry.

Next, the slurry is left in the air for more than an hour, and then water (3 to 5 parts by weight) and appropriate additives are added and mixed to obtain a hardness suitable for the molding method, and then molded. to obtain a molded body.

In this case, when leaving the slurry in the atmosphere (ripening) is stopped, 3 to 20
In order to improve moldability, it is preferable to add a certain amount of cement by weight and mold in the same manner.

The molded body thus obtained is then subjected to ordinary high temperature and high pressure steam curing (180C, 10.51y/ci2) to form a hardened molded body.

The reason for setting the CaO to SiO2 weight ratio to 0.2 to 1.5 and the cement to quicklime weight ratio to 1 to 20 is that if both fall outside of these ranges, the conventional product as shown in the X-ray diffraction diagram in Figure 2 This is because the production of tobermolite is similarly inhibited.

Leaving the slurry prepared with the main raw materials in the air for at least one hour before molding allows the digestion reaction of quicklime at room temperature and the water utilization reaction between silicic raw materials and lime to proceed sufficiently using water as a medium. It's for a reason.

Next, additives will be explained.

As additives to be added to the molding slurry, substantially the same additives as those used in ordinary lightweight cellular concrete, such as thickeners and reinforcing materials, can be used.

In other words, organic thickeners include inorganic thickeners such as carboxymethyl cellulose (hereinafter abbreviated as CMC), methyl cellulose (hereinafter abbreviated as MC), hydroethyl cellulose (hereinafter abbreviated as HEC), polyvinyl alcohol (hereinafter abbreviated as PVA), polyethylene oxide, etc. When a small amount of bentonite, kaolin, etc. is added as a viscous agent, the viscosity and plasticity necessary for molding can be obtained.

In addition, as reinforcing agents, asbestos, alkali-resistant glass fiber,
Blending an appropriate amount of ordinary fibers such as cellulose can improve bending strength and impact resistance.

The cured molded product produced by the method of the present invention produces tobermolite as shown in the X-ray diffraction diagram in FIG. 1 (produced by the method No. 1 of the present invention in the example). Compared to conventional products, this product offers advantages such as significantly improved compressive strength and bending strength, and reduced wet-dry shrinkage.

Examples will be described below.

The powdered main raw materials shown in Table 1 were thoroughly mixed to form a slurry, and then left in a room for 2 hours. Additives such as cement were added to this and mixed, and then the mixture was made into a slurry. was extruded using a Honda Tekko D-150 extrusion molding machine to obtain a hollow panel-shaped extrusion molded body.

Next, the extruded molded product is charged into an autoclave and subjected to normal steam curing (180°C, 10.5 atm) to obtain a hardened molded product.
106, JISAI 129, compressive strength, bending strength, and wet/dry shrinkage were measured.

The results are shown in Table 1 in comparison with the measurement results of products manufactured by conventional methods.

As is clear from Table 1, the compressive strength of the products manufactured using the method of the present invention is approximately twice that of products manufactured using the conventional method, and the bending strength and wet/dry shrinkage ratio are also significantly improved over the conventional products. .

Note that various molding methods other than extrusion can also be used as the molding method.

[Brief explanation of drawings]

FIG. 1 is an X-ray diffraction diagram of a calcium silicate hydrate molded body produced by the method of the present invention, and FIG. 2 is an X-ray diffraction diagram of a calcium silicate hydrate molded body produced by the conventional method.

Claims (1)

[Claims] 1 Quicklime powder and cement as a calcareous raw material blended at a cement/quicklime weight ratio of 1 to 20;
Water is added to a mixture with one or more of powdered silica stone, diatomite, and silica sand blended as a siliceous raw material so that the CaO/Si02 weight ratio is 0.2 to 1.5 to form a slurry, A calcium silicate hydrate molded product, which is left in the atmosphere for one hour or more, and then molded by adding water so that the slurry has a hardness suitable for molding, and the molded product is cured with high-temperature and high-pressure steam. Production method.