JP2563468B2 - Carbonated cured product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an alkaline earth metal carbonation cured product obtained by a novel production method.

[Conventional technology]

It is widely known that hydroxides such as calcium hydroxide, magnesium hydroxide, and dolomite plaster absorb carbon dioxide and harden, but the rate of carbonation is slow, and hardened materials such as marble are industrially obtained. Was difficult.

[Problems to be Solved by the Invention]

This has been done conventionally. In the method of kneading slaked lime, magnesium hydroxide and dolomite plaster with water to absorb carbon dioxide in the atmosphere or carbon dioxide in the air flow of carbon dioxide from the surface of the paste-like molded product to carbonate, carbonation does not occur. Not only does it take a considerable number of days to be carbonated superficially to the inside, but also the carbonation on the surface tends to cause distortion between the inside and the outside, which makes it difficult to obtain a cured product having excellent physical properties.

As a means for solving this problem, this problem cannot be solved unless a method such as cement in which the entire system is hardened on average.

The present invention aims to improve the carbonation rate and obtain a cured product having excellent physical properties.

[Means for solving the problem]

The present inventor, as a result of earnest studies in view of the above points,
The inventors have found that olefinic carbonate is effective as a carbonating agent under wet mixing with alkaline earth metal hydroxides such as slaked lime, magnesium hydroxide and dolomite plaster, and have completed the present invention.

That is, the present invention provides a carbonation-cured product obtained by wet-acting an olefin carbonate on an alkaline earth metal hydroxide.

According to the present invention, the hydroxide of alkaline earth metal such as slaked lime undergoes a carbon dioxide exchange reaction with the above-mentioned olefin carbonate, and slaked lime and the like are carbonated and hardened. However, sometimes this reaction is a rapid reaction, so adjust the reaction conditions appropriately,
A desired cured product is obtained. In the present invention, as a means for controlling the carbonation reaction, a reaction accelerator is used under certain conditions, and a reaction retarder is used under certain conditions to dissolve these hydroxides for further effective reaction. The invention is completed by the combination of agents.

The alkaline earth metal hydroxide of the present invention is slaked lime, hydroxide hydroxide, dolomite plaster, and calcium silicate that produces hydroxide by hydration, cement, etc. Good. Also included are substances that secondary generate hydroxides by reacting with carbonates such as calcium chloride and magnesium chloride.

In the present invention, olefin carbonate such as methylene carbonate, ethylene carbonate and propylene carbonate is used as the carbonation compound.

In the present invention, in order to carry out carbonation with the smallest possible amount of olefin carbonate, the hydroxide of alkaline earth metal is kneaded with the smallest possible amount of water. Further, a pot life at the time of molding is also necessary, and crystallization must be good in order to obtain high strength. To that end, select good reaction conditions,
The objective can be achieved by improving the reaction efficiency.

In this method, the olefin carbonate may be added to the hydroxide as a curing accelerator, a curing retarder and a solubilizer.

As a hardening accelerator, sodium chloride, sodium sulfate and sodium aluminate, and as a hardening retarder, an oxycarboxylic acid salt, 2
-Ketoacetic acid, succinate, EDTA salt, phosphate, wisteria,
Pectin and casein are effective. Further, as a retarder or a reaction rate regulator, lower alcohols such as methanol, ethanol, propanol, butanol, acetone,
Water-soluble solvents such as MEK, methyl cellosolove, THF and DMSO can also be used. As the solubilizing agent, sugars such as sugar and glucose, polyhydric alcohols, calcium chloride, magnesium chloride and the like are effective. When two or more of the above additives are used in combination, the coagulation and curing can be controlled arbitrarily.

In the present invention, an olefin carbonate and an additive are previously blended with slaked lime and magnesium hydroxide powder and the like, and water is added to this to knead, or slaked lime and hydroxide magnesium powder and the like are added to water with an olefin carbonate, an additive and the like. Add the melted or suspended product and knead,
This method is similar to the handling of cement and gypsum.
Further, olefin carbonate, additives and the like may be added to the mixture of slaked lime, magnesium hydroxide powder and the like in water.

If necessary, as aggregate, sand, gravel, etc., bentonite,
Powder fillers such as calcium carbonate and talc, chemical admixtures for cement, pigments, foaming agents and the like can be used.
If necessary, various cements and plasters can be mixed and used.

With olefin carbonate, carbonation can be performed with an addition amount of 20 to 5 parts by weight, so that the efficiency is good and the reaction product is difficult to remain in the system, which is excellent. However, depending on the case, it may be added up to about 160 parts by weight.

The thus obtained cured calcium carbonate and cured magnesium carbonate have a higher hardness than the cured cement, and show hardness almost equal to that of natural products such as limestone. The bending strength and compressive strength differ depending on the water ratio at the time of kneading, but the strength is high when compared to cement under the same conditions at a low water ratio. The shrinkage rate is about 6 × 10 ⁻⁴ , which is larger than that of cement, but this is because the carbon dioxide gas in the air is absorbed and the density increases.

In particular, the ethylene carbonate cured product has good physical properties, and the setting time can be freely adjusted for 24 hours or more after the instantaneous setting. This can be done by combining an oxycarboxylic acid salt and a 2-keto acid salt with a carbonate. .

〔The invention's effect〕

According to the present invention, it is possible to freely produce a raw material that can substitute for cement using inexpensive raw materials such as slaked lime and magnesium hydroxide, and since the product is calcium carbonate, magnesium carbonate, it has high strength. It has high hardness and can provide many useful products not only in the civil engineering and construction industries but also in other fields.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples.
The present invention is not limited to these examples. In addition, "part" in an example is a weight part.

Example 1 100 parts of dolomite plaster, 5 parts of ethylene carbonate,
5 parts sugar, 1 part sodium citrate, 1 part soda ash in water
The solution was dissolved in 30 parts and kneaded. 40 x 40 x this slurry
It was poured into a 160 (m / m) formwork. The setting time is the first 3 minutes,
After 6 minutes from the completion, the composition was exothermicly cured.

This sample was cured in the atmosphere for one week and subjected to a strength test.

Mohs hardness 3.5, bending strength 124 kg / cm ² , compression strength 1100 kg
It was / cm ² .

Example 2 To a paste obtained by kneading 100 parts of magnesium hydroxide with 60 parts of water, 5 parts of ethylene carbonate and 1 part of magnesium chloride were added and kneaded again. The setting was started for 3 hours and 25 minutes, and the setting was finished for 5 hours and 10 minutes.

Example 3 100 parts of dolomite plaster, 10 parts of acetone, 20 parts of water
What melt | dissolved 5 parts of ethylene carbonate in the mixed solution of 1 part was mixed and kneaded well. It generated heat after 3 minutes and hardened after 5 minutes.

The cured product Flexural strength 84 kg / cm ^2, compression strength 413kg / cm ²
Met.

Example 4 To a mixture of 100 parts of slaked lime, 10 parts of alumina cement and 0.1 part of sodium citrate, 35 parts of water was added and kneaded to obtain 40 × 40.
It was poured into a mold of × 160 (m / m) for molding. After curing, the mold was removed, and a 50% ethylene carbonate acetone solution was applied to the surface of the molded body. The hardness of the surface of this molded body increased rapidly, and the Mohs hardness became 2.5 after 7 days.

Example 5 70 parts of slaked lime, 30 parts of quick lime, 5 parts of ethylene carbonate and 5 parts of sugar
Parts, 15 parts of methanol, and 35 parts of water, the mixture was kneaded and exothermicly foamed after 3 minutes and cured after 5 minutes.

This foam had a specific gravity of 0.3 and a compressive strength of 37 kg / cm ² .

Claims (1)

(57) [Claims] 1. A carbonation cured product obtained by wet-acting an olefin carbonate on an alkaline earth metal hydroxide.