JP2000169256A - Production of alc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an autoclaved light-weight concrete (ALC), capable of improving reactivity of silica rock particularly poor in reactivity among ALC raw materials and bettering compression strength and effectively using cutting waste occurring in a production process before an autoclave with respect to saving resource. SOLUTION: In this method for producing an ALC by using a siliceous raw material, a calcareous raw material and gypsum as main raw materials, kneading the main raw materials with a proper amount of aluminum powder, an additive and water to give a slurry, pouring the slurry into a frame mold in which a reinforcing bar is arranged, if required, foaming the slurry, hardening the material for a fixed time, taking out the semiplastic body from the frame mold, cutting the body into a fixed dimension, inserting the cut semiplastic into an autoclave and curing the semiplastic with steam at a high temperature under high pressure, cutting waste of ALC produced before an autclave curing is added to silica rock, mixed and ground by a wet ball mill to give a mixture, which is used as the siliceous raw material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a lightweight cellular concrete (ALC) panel or a lightweight cellular concrete block, which improves the compressive strength of ALC and generates AL before autoclaving which occurs during the production process.
The present invention relates to an ALC manufacturing method for effectively utilizing C cutting waste (hereinafter, cutting waste before autoclave).

[0002]

2. Description of the Related Art Conventionally, as a raw material for ALC, silica stone has been used as a siliceous raw material, quicklime and cement as calcareous raw materials, and gypsum as an additive.

[0003] Of these, silica is known to have the greatest effect on the compressive strength of ALC, and high quality silica is selected so as to obtain high compressive strength, and is selected according to the crushing property and reactivity of the silica. It was important to pulverize to an appropriate particle size. However, in the ALC manufacturing process, there are considerable defective products and debris generated in the cutting process, etc., and these are recycled as raw materials into ALC slurry.
In order to use C without deteriorating its quality, its processing method has been a problem.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in particular, from the viewpoint of resource saving, improves the reactivity of silica, which has particularly low reactivity, among ALC raw materials. An object of the present invention is to provide a method for producing an ALC which improves the compressive strength and effectively utilizes cutting waste before autoclave generated during the production process.

[0005]

In order to achieve the above-mentioned object, the present invention provides a slurry comprising a siliceous raw material, a calcareous raw material and gypsum as main raw materials, and kneading by adding an appropriate amount of aluminum powder, an additive and water. Injected and foamed into the formwork on which the reinforcing steel was placed as needed, and cured for the desired time,
The semi-plastic body is removed from the mold, cut into a desired size, inserted into an autoclave, and subjected to steam curing at high temperature and pressure.
The method for producing LC is characterized in that as the siliceous raw material, a material obtained by adding a cutting waste of ALC generated before autoclaving to silica and mixing and pulverizing with a wet ball mill is used.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, pre-autoclave cutting chips added to silica stone are generated during a normal ALC manufacturing process and are not particularly limited. The amount of addition is 1% by weight to 10% by weight with respect to the silica stone.
In addition to the above, no further improvement in compressive strength is recognized, and a problem arises in that the viscosity of the silica slurry after pulverization increases. When the viscosity of the silica stone slurry increases, the viscosity of the casting slurry obtained by mixing the raw materials of ALC also increases. Therefore, the workability of the slurry decreases, and a problem arises in that cavities around the reinforcing bar and coarse bubbles increase.

[0007] When pulverizing silica with a wet ball mill, the effect of adding cutting chips before autoclaving and mixing and pulverizing to improve the compressive strength is not certain, but is presumed as follows.

[0008] The development of the compressive strength of ALC is achieved by densification of the structure accompanying the formation of tobermorite.

[0009] Tobermorite is produced by the reaction of amorphous calcium silicate hydrate (commonly called CSH) with silicate ions eluted from silica in an autoclave.

In general, since the reaction of tobermorite formation is rate-determined by the dissolution of silica in the autoclave, the finer the particle size, the faster the crystallization of tobermorite. Therefore, it is known that fine-grained silica stone of several μm or less is unsuitable for strength development.

On the other hand, when coarse quartzite having a size of several tens of μm or more is used, it is known that long-time autoclave treatment causes large growth of tobermorite crystals and improves compressive strength. Not suitable from a viewpoint.

In the present invention, it is conceivable that the surface of the silica stone is modified as an effect of adding cutting waste before autoclave and pulverizing the silica stone. That is, the cutting waste before autoclave contains slaked lime [Ca (OH) ₂ ], amorphous calcium silicate hydrate (commonly known as CSH), unreacted silica, gypsum dihydrate and tobermorite. It is considered that a so-called mechanochemical reaction occurs between the crushed and exposed surface of the silica stone, and CSH is generated on the surface of the silica stone.

At this time, in the case of fine-grained silica stone having a size of several μm or less, it is considered that CSH generated on the surface plays a role of a coating film, and the reaction is moderately delayed, so that tobermorite crystals grow large.

On the other hand, in the case of coarse particles, it is considered that crystallization of tobermorite is promptly performed by reaction with silicate ions eluted from the internal silica starting from CSH on the surface.

In the present invention, only a conventional wet ball mill is added with crushed particles before autoclave and crushed, and there is no change in equipment.

There are no particular restrictions on the components of the pre-autoclave crushed debris as long as they contain slaked lime generated in the normal ALC production process.

The silica used as a raw material is not particularly limited, either. However, it is difficult to use the silica in the past. Is particularly effective.

Further, according to the present invention, the compressive strength is improved as compared with the prior art, so that the product density can be reduced, which contributes to a reduction in raw material costs and an improvement in workability.

[0019]

Embodiments of the present invention will be described below.

Table 1 summarizes Examples and Conventional Examples.

The amount of the shavings added before the autoclave was added to the silica stone, and the viscosity of the casting slurry (using a Visco Tester No. 1 rotor manufactured by Rion Co., Ltd.), compressive strength and density were measured.

NO.1 containing no cutting waste before autoclaving. No. 6 compared with the conventional example, 1 to 10% by weight of cutting waste before autoclave was added to silica and pulverized by a wet ball mill. In Examples 2 to 4, the compressive strength was improved. Further, the viscosity of the casting slurry tends to increase, but there is no harm because the viscosity is 4 dPa · s or less.

NO. In Comparative Example 1, since the amount of addition was as small as 0.5% by weight, no improvement in compressive strength was observed.

NO. 5 In Comparative Example, the addition amount was 11% by weight.
However, the improvement in the compressive strength was NO. It can be seen that not only is not recognized as compared to No. 5, but also the viscosity of the casting slurry becomes 4 dPa · s or more, and the workability at the time of casting decreases.

NO. In Examples 8 to 10, NO. 2-4
Since the compressive strength of the sample was sufficiently improved, the amount of aluminum powder added was increased, the foaming amount was increased, and the density was reduced. As a result, NO. 7 In Comparative Example, the compressive strength was less than 4 N / mm ² ,
O. 8 to 10 have a sufficient strength of 5.0 N / mm ² .

NO. In Comparative Example 11, although the amount of addition was 11% by weight, the improvement in compressive strength was NO. Not only is not recognized in comparison with No. 10, but also the viscosity of the casting slurry is 4 dPa · s.
From the above, it can be seen that the workability at the time of casting decreases.

[0027]

[Table 1]

[0028]

As described above, according to the present invention, the ALC which is capable of improving the compressive strength by the surface modification of the silica stone and capable of effectively utilizing the cutting waste before the autoclave of the ALC is extremely excellent in resource saving. Can be provided.

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Claims (1)

[Claims] A slurry obtained by kneading a siliceous raw material, a calcareous raw material and gypsum as a main raw material, adding an appropriate amount of aluminum powder, an additive and water, and injecting into a mold where a reinforcing steel bar is arranged as required, is foamed. After curing for a desired time, the semi-plastic body is taken out of the mold, cut into desired dimensions, inserted into an autoclave, and steam-cured at a high temperature and a high pressure.
ALC characterized in that 1 to 10% by weight of ALC cutting waste generated before autoclave curing is added to silica stone and mixed and pulverized by a wet ball mill to use ALC.
Manufacturing method.