JPH06316409A - Production of hydrate hardened body - Google Patents

Abstract

PURPOSE:To provide a production method of a hydrate hardened body enabling to obtain the useful hydrate hardened body by using various industrial waste products incorporating SiO2. CONSTITUTION:A Ca type water hardening agent producing a hydrate hardening component by reacting with a SiO2 component, is added at the quantity of from 0.05 to <=0.3, in a mol ratio of Ca/Si for a siclic acid raw material consisting essentially of SiO3 to react he mixture with the water under high temperature/high pressure condition in a pressurized oven and obtain the hydrate hardened body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hydrated cured product, and more particularly to a method for producing a hydrated cured product by utilizing various industrial wastes.

[0002]

BACKGROUND OF THE INVENTION In recent years, a large amount of industrial waste has been generated in various fields, and its disposal has become a problem.

Many of these industrial wastes contain SiO ₂ as a main component. For example, it is kira, glass waste, tile waste, coal ash generated from a thermal power plant, cast sand dust, sludge incineration ash, and the like.

Kira is a clay having a large particle remaining after removing silica sand content used in the glass industry field from clay collected from a clay mountain and further removing fine grain frog clay used in the ceramic industry field. It has no special use at present and is discarded as industrial waste. This killer usually contains SiO ₂ in an amount of 80% or more.

Further, the glass dust is generated when glass is processed in a glass factory or the like, and is also rich in SiO ₂ . This too has no special purpose of use and is actually discarded.

Similarly, tile scraps are scraps generated in tile factories and the like, and also contain a large amount of SiO ₂ .

On the other hand, coal ash is ash produced when coal fine powder is put into a flame and burned at once in a coal-fired power plant, and has SiO ₂ as a main component.

This coal ash is an industrial waste which has no special use other than the use as a road aggregate or a landfill material.

On the other hand, the pouring sand is scraps of the mold used for casting, and the sludge incineration ash is the sludge generated by sewage or the like, both of which are industrial wastes containing SiO ₂ as a main component. is there.

[0010] In addition, the glaze sludge is a concentrate of glaze waste used in the field of the ceramic industry, etc.
Since the SiO ₂ content is unstable and contains iron and TiO ₂ , it is a clay with low utility value as industrial waste.

The present inventors have found that these industrial wastes are not
Paying attention to containing ₂ as the main component, as a method of using it, a calcium-based water-hardening agent is added and mixed,
A method for obtaining a hydrated cured product by reacting the mixture with water in a pressure kiln at high temperature and high pressure was developed and proposed in the previous patent application (Japanese Patent Application No. 4-40191).

In the present invention, the desirable Ca / Si molar ratio of Ca / Si in the calcium-based water hardening agent is 0.3 to 3.0, and the more desirable molar ratio is 0.5 to 2.0.
I am trying.

When SiO ₂ and CaO are reacted with water in a pressure kiln to obtain a hydrated cured product, unreacted calcium content is likely to remain in the hydrated cured product, and this unreacted calcium content is later formed. There is a problem that characteristics such as product strength are adversely affected.

A typical hydrated product is a cement hydrated product obtained by reacting Portland cement with water. In this case, CaO is initially Si.
C ₂ S, C ₃ S (C: CaO, S: SiO ₂ ) with O ₂
And other compounds are formed, and they react with water to form a hydrated cured product.

However, the method for producing the hydrated cured product is S
Since the iO ₂ and the calcium-based water curing agent are reacted with water, there is a problem that the calcium content is likely to remain in the cured product in the unreacted state. If left on, the product characteristics may deteriorate over time.

[0016]

According to the present invention, the required strength can be obtained and the unreacted calcium content can be reduced as much as possible, and the adverse effect due to the residual unreacted calcium content after hydration hardening can be suppressed as much as possible. It was made for the purpose of providing a method of obtaining it.

In the invention of the present application, therefore, a calcium-based water hardening agent which reacts with a SiO ₂ component to produce a hydration hardening component is added to Ca / S for a siliceous raw material containing SiO ₂ as a main component.
It is characterized in that it is added in an amount such that the molar ratio of i becomes 0.05 to less than 0.3, and the mixture is reacted with moisture in a pressure kiln at high temperature and high pressure for a predetermined time to obtain a hydrated cured product ( Claim 1).

Another aspect of the present invention is to hydrate a siliceous raw material prepared so that the ratio of crystalline SiO _{2 to} the total SiO ₂ is 15% by weight or more, by reacting with a SiO ₂ component. A hydrated cured product is obtained by adding a calcium-based water-based curing agent that produces a curable component and reacting the mixture with moisture in a pressure kiln at high temperature and high pressure for a predetermined time (claim 2).

[0019]

According to the invention of claim 1, a hydrated cured product is obtained by reacting SiO _{2 as a} siliceous raw material with a calcium-based water curing agent together with water. Industrial waste, which has no conventional use and is difficult to treat, can be effectively utilized as a SiO ₂ -containing siliceous raw material, and a more useful hydrated cured product can be obtained.

Further, according to the present invention, it is possible to hydrate and harden the alkali content which is an obstacle to the hardening reaction of cement even if it is contained in the material. Even if it is contained in a fixed amount, it can be cured.

However, in order to smoothly carry out the curing reaction, S
The content of iO ₂ is preferably 30% or more, and more preferably 50% or more.

In the present invention, such a calcium-based water hardening agent and SiO ₂ are reacted with water at high temperature and high pressure under the conditions of a temperature of 100 to 300 ° C. and a pressure of 1 kgf / cm ^2. As described above, the reaction time is preferably 30 minutes or longer, and more preferably the temperature is 150 to 200.
C, pressure is saturated steam pressure or more at each treatment temperature, and reaction time is 2 hours or more.

In the present invention, the molar ratio of Ca and Si is Ca / S.
It is characterized in that i is 0.05 to less than 0.3. In the case of a cement material, for example, a typical Portland cement material, C ₂ S and C ₃ S are main components, and the stoichiometric ratio of Ca and Si is such that the molar ratio of Ca is in excess of the molar ratio of Si. is there.

However, in the case of the method of the present invention in which SiO ₂ and a calcium-based water hardening agent are reacted with water, C
The proper molar ratio of a to Si, especially the proper Ca / Si molar ratio for reducing the residual unreacted calcium content as much as possible and expressing the required strength, is not clear. As a result of various studies, the hydration cured product exhibits sufficient strength even if the molar ratio of Ca to Si is less than 0.3 which is the lower limit of the desirable molar ratio in the above-mentioned prior application. If the amount is less than 0.3, the residual amount of unreacted calcium content in the hydrated product is effectively reduced (or eliminated), and the fact that Ca is required to be at least 0.05 mol or more found.

The present invention has been made based on these findings. According to the present invention, the residual unreacted calcium content of the hydrated cured product can be reduced and the deterioration of the product characteristics over time can be suppressed. Therefore, the original product characteristics can be retained continuously. In the present invention, Ca / Si
The reason why the molar ratio is 0.05 or more is that a hydrated cured product cannot be obtained satisfactorily when Ca is less than this.

Incidentally, there are cases where SiO ₂ is contained in a crystalline form and cases where it is contained in an amorphous form. Therefore, when the present inventor investigated the influence of these forms, the crystalline form was found. Has a higher reactivity with a calcium-based water-curing agent than the amorphous form, and thus the strength of the obtained hydrated cured product is high, and the amount of calcium content remaining in the cured product in an unreacted state is small. It was also found that when the ratio of crystalline SiO ₂ as the siliceous raw material is a certain ratio or more, a practically desirable strength can be obtained, and the residual unreacted calcium content can be suppressed to a practically unproblematic range.

Therefore, according to the second aspect of the present invention, the hydrated hardening product which can terminate the hydration hardening reaction rapidly and has excellent strength, and which has a small amount of residual unreacted calcium content, that is, little deterioration in characteristics over time, is obtained. Can be obtained.

[0028]

EXAMPLES In order to further clarify the characteristics of the present invention, examples thereof will be described in detail below. Chamotte as tile waste is used as a siliceous raw material, and CaO (reagent) is added to this.
In addition at various molar ratios (Ca / Si) to iO ₂ ,
Further, an appropriate amount of water is added and mixed in an Al ₂ O ₃ mortar, and 6 g of the mixture is subjected to a surface pressure of 300 kgf / cm ^{2 with a} uniaxial pressure molding machine.
By dry press molding to obtain a molded body of 10 × 10 × 40 mm.

These molded bodies were autoclaved to 18
It was treated at 0 ° C. saturated water vapor pressure (10 kgf / cm ² ) for 5 hours. The bending strength of the obtained hydrated cured product was measured, and the results shown in Table 1 were obtained.

In the bending test, a test piece of 10 × 10 × 40 mm was used, a span of 30 mm and a crosshead speed of 0.
A 3-point bending test was performed under the condition of 5 mm / min.

[0031]

[Table 1]

Next, using crystalline quartz as a siliceous material, a molded body was prepared, a hydration hardening reaction and a bending test were conducted in the same procedure as above. However, in this example, the reaction temperature for hydration hardening was changed variously. The results are shown in Table 2.

[0033]

[Table 2]

From the results shown in Tables 1 and 2, Ca / Si
That a hydrated cured product having a predetermined strength is obtained with a molar ratio of 0.05 or more, and quartz is used as the siliceous raw material
It can be seen that at a reaction temperature of 150 ° C. or higher, the strength reaches a peak at a molar ratio of 0.5. That is, if only the initial strength is considered, the result shows that the strength increases up to a molar ratio of 0.5.

Next, when crystalline quartz and amorphous fused quartz were used as the siliceous raw materials and the same test was performed to compare them, the results shown in Table 3 were obtained.

[0036]

[Table 3]

From these results, it is found that the strengths of the hydrated cured products obtained from crystalline and amorphous are different, that is, the use of crystalline products gives higher strength at each temperature. I understand.

Next, Table 4 shows the results of examining the remaining unreacted calcium content by producing hydrated cured products by changing the Ca / Si molar ratio and the reaction temperature.

[0039]

[Table 4]

From the results shown in Table 4, the Ca / Si molar ratio was 0.
If it is 3 or more, unreacted calcium content is likely to remain in the hydrated cured product, and the amount of unreacted calcium content increases as the molar ratio exceeds 0.3. In the case of high quality fused quartz, the reactivity is lowered, so that it is found that a large amount of unreacted calcium content tends to remain in the hydrated cured product even if the reaction temperature is increased.

Table 5 shows crystalline SiO as a siliceous raw material.
Using a mixture of a ₂ and amorphous SiO _2, and the mixing ratio shows the results when subjected to property test while varying the total SiO the SiO ₂ crystalline From this result _It can be seen that by mixing 15% by weight or more with respect to ₂ , a value of 3 MPa or more, which is a measure of practical strength, can be obtained and the amount of unreacted calcium can be reduced.

[0042]

[Table 5]

Although the embodiment of the present invention has been described in detail above, this is merely an example. For example, in the present invention, it is possible to use a siliceous raw material other than the above-mentioned industrial waste, and in the invention of claim 2, the Ca / Si molar ratio is 0.
It is also possible to adopt ratios other than 05 to less than 0.3. Others The present invention can be implemented in variously modified forms based on the knowledge of those skilled in the art without departing from the spirit of the invention.

Claims (2)

[Claims] 1. A calcium-based water-curing agent that reacts with a SiO ₂ component to form a hydration-curable component with respect to a siliceous raw material containing SiO ₂ as a main component and has a Ca / Si molar ratio of 0.0.
A method for producing a hydrated cured product, which comprises adding the mixture in an amount of 5 to less than 0.3 and reacting the mixture with water in a pressure kiln at high temperature and high pressure for a predetermined time to obtain a hydrated cured product. _2. A hydrate-curable component is produced by reacting with a SiO ₂ component to a siliceous raw material prepared so that the ratio of crystalline SiO _{2 to} the total SiO ₂ is 15% by weight or more. A method for producing a hydrated cured product, which comprises adding a calcium-based water-based curing agent and allowing the mixture to react with water in a pressure kiln at high temperature and high pressure for a predetermined time to obtain a hydrated cured product.