JPS61163117A - Caustic lime having retarded reactivity for hydration - Google Patents

Abstract

PURPOSE:To produce caustic lime capable of inexpensive production with remarkably retarded reactivity by adding a small amt. of a specified additive to CaO and heat-treating at low temp. after crushing. CONSTITUTION:Ordinary CaO obtd. by the calcination of lime-stone is crushed to ca. 1-5mm grain size. The product is further crushed by adding <=5wt% at least one among higher fatty acid glyceride, methyl hydrogen polysiloxane, alkyl silicone, and ethyl silicate to adjust the Blaine specific surface area to ca. 2,000-7,000cm<2>/g. The caustic lime having retarded hydration reactivity is obtd. by heat-treating obtd. powder at 40-400 deg.C. Since there is a close relation between the heat-treating temp. and the hydration time, and the hydration time becomes longer as the heat-treating temp. is elevated, the hydrating time can be controlled. The material is utilized effectively as static crushing material and soil conditioner, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for suppressing the hydration reaction of quicklime, and more specifically, a method for suppressing the hydration reaction characterized by coating quicklime to form a film on the surface.

Quicklime expands by about twice its size due to the aqueous phase, and the expansion pressure generated at this time is also large, so it is effective as a static crushing material, soil improvement material, etc. C: It is used, but when mixed with water it instantly However, it is desired to develop quicklime that suppresses this aqueous phase reaction.

Conventional techniquesConventional methods for suppressing hydration reactions include (b) baking lime at high temperatures, (b) adding copper, iron, and silica to lime.

Create chestnut/car by adding compounds such as titanium and firing.
A method of pulverizing this (Japanese Unexamined Patent Publication No. 115376/1983). G/-1 A method of using alcohol, sodium silicate, caustic soda, glycerin, ethylene glycol, shields, polyaminocarboxylic acids, and oxyl&' as an aqueous phase inhibitor (aqueous phase reaction retarder).

(Gypsum 1 lime hand 7 tsuku, civil engineering construction dyeing MP387-38
& 1971 edition), etc. are known. The method (2) requires firing at high temperatures for a long time, which requires special equipment and is expensive. Method (b) requires equipment such as a kiln, and processes such as high-temperature firing and pulverization, resulting in high costs like method (b). Vl Method Reference (Ishisagi 1 Lime Handbook) As is clear from the drawing, the inhibitory effect is small and a large amount of retardant is used! Even if you use it, the delay effect will be around 50 minutes at most.

As described above, the conventional methods have not yet produced quicklime in which the aqueous phase reaction is satisfactorily suppressed.

Problems to be Solved by the Invention The present inventors have discovered a method for inexpensively producing quicklime in which the hydration reaction is suppressed, eliminating the drawbacks of conventional methods, and have arrived at the present invention. That is, the present invention combines quicklime with higher fatty acid glyceride, methylhydrodiene polysiloxane, alkyl silicone,
Quicklime with suppressed hydration reaction characterized by adding at least one strain of alkyl silicate to 5 weight i'% or less, pulverizing, and then heat-treating the C double chain mixture at 40 to 400 ° C. .

Means for Solving the Problems In the present invention, as a raw material, ordinary quicklime obtained by forming limestone is mixed with 1 to 5 trnl of rice grain, and the water phase time is usually within 1 minute. Therefore, it is impossible to make effective use of the aqueous phase. However, the aqueous phase time of the quicklime of the present invention can be from 10 minutes to 4 hours or more.

The quicklime used as the ζ2 raw material of the present invention is not limited to raw materials or production methods, and any kind can be used. In other words, pure coal stone or dolomatic material can be used as a raw material for quicklime.
Grind into higher fatty acid glycerides, methylhydrodiene polysiloxane.

Alkyl silicone, ethyl silicate containing at least 111 [
Add up to 5% by weight and grind to give a plain specific surface area of 200
0 to 7000i, /r. The obtained powder is 40 to 4
Heat treatment at 00°C increases the water phase suppressing effect.

Even if the amount added exceeds 5M fluorite, there is almost no change in the aqueous phase suppressing effect (this is unprofitable from an economical point of view.It is preferably less than 5 couls).

When the heat treatment temperature exceeds 400°C, it is not preferable from the viewpoint of decomposition and release of additives, and the temperature is preferably 350°C or lower. If the heat treatment temperature is less than 40°C, the water phase time will not be too long and it will be difficult to achieve the objective.

The heat treatment temperature and water phase time are closely related, and as the heat treatment temperature increases, the water phase time becomes longer, thereby making it possible to control the water phase time.

Effect In the present invention, the effect of suppressing the aqueous phase is increased by carrying out the heat treatment at 40 to 400°C. In this process, the additives are uniformly dispersed to form a film on the surface of the quicklime, and a strong film is formed by further promoting the reaction of the additives by heat treatment, and the contact between water and quicklime and C; It is characterized by suppressing.

Example 1 0.51 amount of quicklime 15091 dimethylhydrodiene polysiloxane with a particle size of 1-5 Ml was added, and the content was 1
．． The mixture was placed in a No. 26 steel pot mill along with 30 still poles each having a diameter of 1,220 mm and pulverized and mixed for 30 minutes. The obtained powder has a plain specific surface area of 5700 to 6700 cd.
/l. When this powder was heat treated at 45°C for 24 hours, it turned into water.

The total time was 13.6 minutes, and when heat treatment was performed at 300° C. for 30 minutes, the water phase time was about 140 minutes. Table 1 shows the results obtained under other heat treatment conditions.In contrast, when the same additives as in Example 1 were used but no heat treatment was performed, the aqueous phase time was 1 minute or less.

Table 1 Example 2 Table 2 shows the heat treatment conditions and hydration time of a water phase suppressed quicklime produced by adding 1% by weight of methylmethoxy silicone in the same manner as in Example 1.

Table 2 Example 3 Table 3 shows the heat treatment conditions and aqueous phase time when hydration-suppressed quicklime was produced by adding IN amount of natural linseed oil containing fatty acid glycerides by the same method as in Example 1.

This result shows that it is possible to use inexpensive natural substances containing large amounts of expensive synthetic raw materials as additives, without using them as additives.

Table 3 Example 4 Table 4 shows the heat treatment conditions and water phase time when aqueous phase-suppressed quicklime was produced by adding ethyl chloride as a silica alkyl in the same manner as in Example 1.

Table 4 Example 5 By the same method as in Example 1, 0.1 to 5.0 weight of methylhydrodiene polysiloxane was added, and 1
Table 5 shows the hydration time when hydration-suppressed quicklime was produced by heat treatment at 50° C. for 30 minutes.

Table 5 The results show that even if the amount added exceeds 1% by weight, the hydration suppressing effect increases little, and if it exceeds 5:1 itit%, it is uneconomical.

Effects of the present invention According to the method of the present invention, the hydration reaction of quicklime can be suppressed by adding a small amount of additives to ordinary quicklime I and heat-treating it at a low temperature (40 to 400°C), thereby reducing raw material costs. It is extremely advantageous industrially, not only in terms of reduction, but also in reduction of fuel costs and furnace material costs.

Claims (1)

[Claims] 1) Adding 5% by weight or less of at least one of higher fatty acid glyceride, methylhydrodiene polysiloxane, alkyl silicone, and alkyl silicate to quicklime, pulverizing it, and then heat-treating the mixture at 40 to 400°C. Quicklime with suppressed hydration reaction.