JPS60200873A - Manufacture of alc - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing aerated concrete (hereinafter abbreviated as ALO).

More specifically, the present invention relates to a method for producing ALO using granulated blast furnace slag as the main raw material.

ALO is made by pulverizing silicic acid raw materials such as silica sand and silica stone, and calcareous raw materials such as lime and cement, adding an appropriate amount of water and a small amount of metal aluminum powder, stirring, and then allowing it to stand still. Alternatively, without adding metal aluminum powder, air is mixed into the slurry to make it contain air bubbles, semi-plasticized, and then transferred to an autoclave and subjected to high-temperature, high-pressure steam curing.

Although ALO manufactured in this way has physical properties such as compressive strength, wet-dry shrinkage, and heat insulation properties as a building material, it is desired that ALO have better performance. Various additives have been proposed or put into practical use to improve the performance. For example, a small amount of an aluminum-containing substance such as bauxite, kaolin, or aluminum hydroxide may be added for the purpose of promoting crystallization of calcium silicate hydrate, which is the main component of ALO products.

However, although these additives have certain effects, they also have many drawbacks and pose many problems in practical use.

In other words, bauxite has parts that are not easily crushed during crushing, and it takes a long time to homogeneously crush these parts, and the high content of iron oxide causes the product to be colored. Aluminum hydroxide increases the viscosity of the raw material slurry and disturbs bubble formation in the foaming process, and like kaolin, aluminum hydroxide increases the viscosity of the slurry and the reaction rate is too fast, leading to crystallization of calcium silicate hydrate. During the hydrothermal reaction in an autoclave, compounds have already been formed with other substances, and most of them have disadvantages such as not working effectively as additives.

When manufacturing ALO without the above drawbacks, the quartz content (quality) of the silicic acid raw material, the reactivity (quality) of quartz during hydrothermal reaction, etc., have a subtle influence on the quality of the product. is publicly known.

However, it is difficult to produce silica sand and silica stone that always satisfy both of the above requirements, and there are resource constraints.

On the other hand, when looking at calcareous raw materials, it is similarly difficult to constantly supply quicklime and cement suitable for the above-mentioned reactivity.

Against the background of such resource issues, in recent years granulated blast furnace slag, a resource that has both silicic and calcareous properties, has been used as a raw material for cement by approximately 5% by weight, A'
It is used in the raw material of L O in an amount of 4.0 to 50% by weight.

However, the content of AIO in granulated blast furnace slag is as high as 10 to 20% by weight. And like this At
03 When ALO is manufactured using raw materials with a high content, the solid solution of At O in calcium silicate hydrate is said to be about 34% by weight, and it is said that the amount of At that exceeds this is about 34% by weight.
When O is included, a so-called bite logger 3 net is generated, which has a fatal drawback of significantly reducing the compressive strength of the product.

An object of the present invention is to provide a method for producing ALC that eliminates the above-mentioned drawbacks even when a large amount of granulated blast furnace slag is used as the main raw material.

In order to achieve this objective, the inventors of the present application have conducted extensive research and found that the amount of 40 to 50 Using granulated blast furnace slag powder in an amount equivalent to 1% by weight, 0.5 to 4% by weight of one or more of powdered 7erosilicon, metal silicon, or silicon carbide is added thereto, and the following is carried out according to the usual method. The present method was developed based on the discovery that when ALO is produced, it is possible to almost suppress the formation of hydrogarnet and a product with sufficient strength as ALC can be obtained.

That is, the method of the present invention uses siliceous raw materials such as silica stone and silica sand, cement, and granulated blast furnace slag in powder form as main raw materials, adds quicklime as necessary, and At least 50% by weight of metal silicon, ferrosilicon or silicon carbide is added to the powder, preferably 200 meshes or less, so as to contain 0.5 to 4% by weight, and then an appropriate amount of silicon carbide is added. Water is added and mixed, and ALC is then produced according to a conventional method.

In the method of the present invention, the reason why the amount of metal silicon, ferrosilicon, etc. added is limited is that the effect of the present invention is not noticeable if it is less than this, and if it is added more than this, rapid heat generation occurs during hydration of calcium silicate. This is because cranking occurs at the time of plasticization.

It is not clear why the additive of the present invention has such high reactivity, as it has a remarkable effect in such a small amount, and cranking occurs when used in excess.

The ALC obtained by the method of the present invention generates very little hydrogarnet even when granulated blast furnace slag containing 10 3 weight % or more of AtO is used as the main raw material to about 60 weight %. It is possible to reliably obtain a material with sufficient strength.

In addition, when using poor-quality silica stone with a low Si0 content of 85% by weight as the main raw material, or when using cement with a relatively low Si content of 85% by weight,
Even in the case of using a material with a high tO content3, by applying the method of the present invention, it is possible to easily obtain a product with properties equivalent to or better than conventional ALO.

In the method of the present invention, quicklime is not normally used, but when used in an appropriate amount of about 3 to 5% by weight, it is effective in accelerating hardening during semi-plasticization, so it is acceptable in terms of cost. If so, you can also add quicklime.

Examples will be described below.

Examples: 10 to 60 parts by weight of granulated blast furnace slag, 5% or less of metallic silicon, silicon carbide, or the trade name Toyonoguta, based on the total solid content of an ordinary Portland cement mixture.

- Add ferrosilicon manufactured by Toyo Denka (both have a mesh size of 200 or less and 50% by weight or more), add 67 parts by weight of water, and proceed with the following normal operations to produce ALO and ALC products. Compressive strength (J Engineering SA i16)
Comparative values of bead and hydrogarnet were measured.

Comparison of the beads of the above-mentioned hydrogarnet. Raw materials (no added quicklime, silica stone is S i 0 2
95% by weight) without additives (jil16
) was set as 100, and the numerical value corresponding to this value was set as the comparison value.

The results are shown in Table 2 in comparison with reference examples.

The values of the main components of the granulated blast furnace slag and ordinary Portland cement used in this example are shown in Table 1, and the results of waveform identification of hydrogarnet by X-ray diffraction are shown in the figure for reference.

In addition, the compressive strength was 40 kgf10trb or more, and the peak value of No. 1 drogarnet was 30 or less as a guideline for passing the product.

Table 1 Granulated blast furnace slag OaO SiO 7I7! OSK
O NaO2 23 2 2 41, 20 33.21 11.70 1.05 -
-Ordinary Portland cement 61.4・8 21.8
8 5.29 2.27 0.75 0.54 Granulated blast furnace slag FeO Mg.

3 Ordinary Portland cement 2.82 1.51 2nd
Notes on the table) The x mark indicates a silica stone with a low SiO grade, and the clay contained as an impurity contains 10% by weight or more of alumina.

As is clear from Table 2, Experiment A shown as a reference example
6 and 16 (no additives added) and Experiment AI+ in which additives were added beyond the range of the method of the present invention, all showed sufficient compressive strength despite using a large amount of granulated slag,
The peak comparison value of hydrogarnet was also low.

Incidentally, although there is a correlation between the hydrogarnet comparison value and the compressive strength, there were cases where the strength was weak even if the hydrogarnet comparison value was sufficiently low, such as in Experiment A14.

This appears to be the result of the formation of fine racks during semi-plasticization as described above.

The figures attached for reference are the powder method X-ray diffraction charts of experiments A6 and j610, but experiment A6, which used a large amount of granulated slag as a raw material without using any additives according to the present invention, had a clear hydrogarnet structure. ) (HG), but in the experimental AIO, it is seen that the peak has become significantly smaller. or,
As shown in Experiments A17 and A18, ALO with reasonable properties was obtained even when poor quality silica was used as the raw material.

[Brief explanation of drawings]

The figure shows powder method X-ray diffraction chart 1 of some samples. HG...Hydro Garnet. Applicant: Sumitomo Metal Mining Co., Ltd. ,/recitation-)・5,

Claims (1)

[Claims] (1) In a method for manufacturing ALO that uses siliceous raw materials such as silica stone, cement or cement and a small amount of lime, and granulated blast furnace slag as the main raw materials, 0% of the total solid content of the mixture of the above-mentioned main raw materials is used. A method for producing ALO, characterized in that one or more of powdered metal silicon, ferrosilicon, or silicon carbide is added so as to contain .5 to 7 I.% by weight.