JPS62220657A - Expansible tablet for static crushing - 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] (Industrial Application Field) The present invention relates to a static crushing agent that statically crushes brittle objects such as rocks and concrete, and more specifically, it relates to a static crushing agent that statically crushes brittle objects such as rocks and concrete. This relates to static crushing agents.

(Prior Art and Problems) In recent years, static crushing agents have been widely used that statically crush rocks, concrete, etc. by using the expansion pressure generated during the hydration reaction of quicklime. Static crushing agents have the great advantage of being non-polluting and safe, without the vibrations, noise, flying stones, etc. that accompany explosions, unlike gunpowder, and can be used in place of explosives. It's becoming more common. However, the static crushing agents currently on the market have an expansion pressure of 300 to 400 kg/- compared to explosives, and require a much larger number of holes to crush extremely small and brittle objects. It has the disadvantage of poor performance and high cost. Furthermore, commercially available static crushing agents have a slow expansion pressure rate that can crush brittle objects.
It takes 24 hours, and compared to gunpowder, it is less workable and efficient, and improvements have been strongly desired.

The present inventors have made repeated studies in view of these points, and as shown in Japanese Patent Application Laid-Open No. 58-82152,
We learned that an expandable tablet for static crushing made by compression molding an expansion agent mainly composed of quicklime and substances that retard its hydration reaction can generate expansion pressure within one hour and crush brittle objects. .

However, it was subsequently found that the expansion pressure development rate of this statically crushable expandable tablet has a very large temperature dependence. For example, at a temperature of 20°C, it was possible to crush a brittle object within one hour, but at a temperature of 15°C, the rate of development of expansion pressure becomes extremely slow and the resulting expansion pressure decreases, making it impossible to crush a brittle object. become unable. In this way, in this expandable tablet for static crushing, the rate of expansion pressure development is highly dependent on temperature, and the expansion pressure obtained is also small, making it impossible to crush brittle objects with the slightest change in temperature.
Practical use at actual construction sites, etc.
It was impossible.

Further, as a result of extensive research, the present inventors used quicklime as an expansible component and molded a powdered composition in which it was combined with an inorganic hydration reaction retardant and an inorganic hydration reaction accelerator. Static crushable expansible tablets with
00K9/lri and that the temperature dependence of the expansion pressure development rate is small,
The invention has been completed.

(Means for solving the problem) That is, the present invention uses quicklime as an expansive component,
This expansible tablet for static crushing is made by compression molding a powder composition in which this powder is combined with an inorganic hydration reaction retardant and an inorganic hydration reaction accelerator.

The present invention will be explained below.

The present invention consists of three essential ingredients: quicklime, an inorganic quicklime hydration retardant, and a quicklime inorganic hydration accelerator.

The hydration reactivity of the quicklime used as the expansive component in the present invention varies depending on the degree of calcination, but so-called soft-calcined quicklime has a hydration rate too fast to be useful. On the other hand, dead burnt lime, which is used in commercially available static crushing agents and whose hydration rate is considerably suppressed, has a hydration rate that is too slow and is difficult to use.
Hard calcined lime, which is calcined at a temperature of about 00° C., is most preferable because its hydration rate can be easily controlled with a hydration reaction retardant and a hydration reaction accelerator.

The quicklime hydration reaction retarder used in the present invention includes boric acid, inorganic borates such as sodium borate, potassium borate, and calcium borate, inorganic sulfates such as sodium sulfate and calcium sulfate, and fluoride. At least one type selected from lithium, inorganic heptadides such as sodium silicofluoride, and inorganic sulfides such as calcium sulfide is used. In an expansible tablet made of quicklime alone or quicklime and a quicklime hydration reaction accelerator without adding a quicklime hydration reaction retardant, the gun phenomenon (heat of hydration accompanying the quicklime hydration reaction) This creates a dangerous phenomenon in which water vapor is generated and the water vapor pressure inside the hole increases, causing the crushing agent filled in the hole to spray out from the hole opening, making it impossible to crush the brittle object.

It is not clear why these quicklime hydration reaction retarders prevent the gunshot phenomenon, but these hydration reaction retarders
This is thought to be because it has the effect of delaying the powder disintegration caused by the expansion of the quicklime in expansible tablets, allowing the water vapor generated thereby to pass through the spaces between the tablets and sufficiently escape out of the pores, thereby preventing the water vapor pressure within the pores from increasing. Ru. Expandable tablets made of quicklime alone or quicklime and a quicklime hydration accelerator will rapidly disintegrate into powder when the quicklime begins to hydrate.The gaps between the tablets will be closed, and the generated water vapor will be directed outside the pores. It is thought that the gun cannot be released and a gunshot phenomenon occurs.

The quicklime hydration promoter used in the present invention is at least one selected from inorganic chlorides such as lithium chloride, magnesium chloride, calcium chloride, and aluminum chloride, and inorganic nitrates such as sodium nitrate, magnesium nitrate, and aluminum nitrate. Use types. In an expansible tablet made of quicklime and a quicklime hydration retardant without the addition of a quicklime hydration reaction accelerator, the gunshot phenomenon does not occur;
As mentioned above, the temperature dependence of the expansion pressure development rate becomes extremely large, making this method impractical.

The optimum ratio of the three components in the present invention varies depending on the degree of calcination of the quicklime and the type of hydration reaction retardant or hydration reaction accelerator used, but the ratio of the quicklime hydration reaction retarder to 100 parts by weight of quicklime is 0.1 to 10 parts by weight, and preferably 0.1 to 5 parts by weight of the hydration reaction accelerator. If the hydration reaction retarder is less than 0.1 parts by weight, it cannot exhibit its effect and a gunshot phenomenon occurs, and if it is more than 10 parts by weight, the rate of expansion pressure development becomes slow and it becomes impossible to crush within one hour. If the hydration reaction accelerator contains less than 0 or i parts by weight, it will not be able to exhibit its effect, and the temperature dependence of the expansion pressure development rate will become large and the obtained expansion pressure will decrease. However, the effect remains the same, but the content of quicklime, which is an expanding component, decreases and the expansion pressure decreases, which is not preferable. The content of quicklime, which is an expansible component of the expansible tablet of the present invention, is 86.9~
This is 918%, which is larger than that of commercially available static crushing agents of 60 to 80 cm, and therefore the resulting expansion pressure is also large.

A feature of the present invention is that a powdered composition consisting of the above-mentioned three essential components is molded into tablets. This eliminates the cumbersome work of making a slurry with water and quickly pouring it into the holes at the crushing site, which is the case with powdered static crushing agents currently on the market. Workability can be improved by injecting water from the hole. In addition, the water vapor generated by the heat of hydration accompanying the hydration reaction of quicklime can be released out of the hole through the gap between the tablets, thereby preventing the gunshot effect. Since the commercially available static crushing agent is in powder form, the hydration rate of quicklime is fast, and when water vapor is generated by the heat of hydration, it cannot escape out of the hole, and a gunshot phenomenon is sure to occur. Commercially available static crushing agents use quicklime with a very low hydration rate to prevent the gunshot phenomenon, and as a result, the expansion pressure development rate is slow. Since it can prevent this, quicklime with a high hydration rate can be used and the expansion pressure development rate is also fast.

The expandable tablet for static crushing of the present invention can be made by molding a powdered composition consisting of the three components described above using a tablet machine, briquette machine, or the like. The shape of the tablet is
It is preferable that the water injected through the hole can easily permeate and disperse to the bottom of the hole, and that the generated water vapor can easily pass between the tablets and be released outside the hole, and preferred shapes include spheres, discs, and cylinders. The volume of the tablet is determined based on the ease of filling the holes, the ease of water penetration, and the size of the resulting expansion pressure.If the hole diameter is generally 30 to 100 mJ1φ,
A volume of 0.05 to 10 m is preferred. The volume is 0.
If it is less than 05clIf, it becomes difficult for water to penetrate to the lower part of the pores, and the crushing effect becomes smaller. The cost of one-shot molding increases. - If the force is 10C or more, the amount of tablets filled into the holes will become smaller and the voids will become larger.9 The expansion pressure will become smaller. The hardness of the tablet must be such that the tablet does not lose its shape until the pores are filled and water is injected and the hydration and expansion reaction begins and the generated water vapor passes between the tablets and is released outside the pores. , the bulk specific gravity is preferably in the range of 2.0 to 3.2. Bulk specific gravity? If the depth is less than 0, the tablet will be easily broken, and if the depth is 3.2 or more, it will be difficult to manufacture the tablet and the penetration of water into the inside of the tablet will be too slow, which is not preferable.

(Effects) The expandable tablet for static crushing of the present invention improves workability by omitting the work of making a slurry of crushing agent powder with water and quickly pouring it into holes, which is the case with conventional commercially available static crushing agents. will improve. - In addition, the crushing process can be completed in less than 1 hour, compared to the 12 to 24 hours that conventional commercially available static crushing agents require, greatly improving work efficiency.

In addition, the expansion pressure obtained is greater than that of commercially available static crushing agents, and the number of holes for crushing brittle objects can be reduced, improving work efficiency and economic efficiency. Furthermore, the present invention has a small temperature dependence of the expansion pressure development rate, and can stably develop expansion pressure in a short time of one hour over a wide temperature range, so that systematic crushing work can be carried out reliably. be able to.

(Example) Next, the present invention will be specifically explained with reference to Examples.

Example 1 The expansion pressure development rate of the expandable tablets for static crushing of the present invention shown in Table 1 was measured using an expansion pressure measuring device as shown in FIG. Hard-burned quicklime produced by burning limestone at about 1300° C. was used as the quicklime. Tablets are manufactured by molding powder using a briquette machine, and have a volume of 1.5-1.
It has an electric specific gravity of 2.5 and an almond-shaped shape. temperature is 10℃
and 20°C. The results at 10°C are shown in Figure 2, and the results at 20°C are shown in Figure 3.

For comparison, the expansion pressure was also measured for tablets made by molding powders made of quicklime and a quicklime hydration retardant, and for a commercially available powdered static crushing agent. The result @
Shown in Figures 2 and 3.

The inflation pressure was measured by the method described below.

Length 6 with the bottom welded and sealed with a steel plate l as shown in Figure 1
00 su s Two locations in the center of steel pipe 2 with an outer diameter of 60 m5 and an inner diameter of 40 txx! Cut the screw 〃 and set the pressure transducer there so that its sensitive surface is located on the inner wall surface of the steel pipe. Expandable tablets for static crushing are filled into a steel pipe, water is injected through the hole, and the expansion pressure is measured with a pressure transducer at each elapsed time.

Example 2 and Comparative Examples 2 to 6 Specimens were prepared by drilling one hole in 60 cm square unreinforced concrete with a hole diameter of 50 wgφ and a hole length of 57 cWI.

Drainage water filled with the expandable tablet for static crushing of the present invention shown in Table 2 was injected into this hole, and the crushing status of the concrete was observed. As the quicklime, hard-burned quicklime obtained by baking limestone at about 1300° C. was used. The tablets are molded using a briquette machine, have a volume of 1-5aIs, a bulk density ratio of 6, and an almond-shaped shape. The temperature was 10°C.

For comparison, as shown in Table 2, quicklime alone, quicklime and quicklime hydration retardant, quicklime and quicklime hydration accelerator formed into tablets, quicklime and quicklime hydration retarder plus quicklime. A hydration accelerator used in powder form without being molded, and a commercially available static crushing agent were similarly tested. The results are shown in Table 2.

Margin below

[Brief explanation of drawings]

FIG. 1 is a perspective view of an apparatus for measuring inflation pressure. Second
The figure and FIG. 3 are graphs showing the relationship between the elapsed time and the expansion pressure development rate of the tablets of Example 1 and Comparative Example 1. L...Copper Plate 2...Steel Pipe 3...Bore Port 4...Pressure Sensor Patent Applicant Asahi Kasei Corporation Figure 1

Claims (1)

[Claims] An expansible tablet for static crushing made by compression molding a powder composition using quicklime as an expansible component and combining this with an inorganic hydration reaction retardant and an inorganic hydration reaction accelerator.