JPH0655938B2 - Crushing agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a crushing agent for rocks, concrete structures and the like.

[Prior Art] Many crushing agents that utilize the expansive force of hydrated quicklime have been proposed. As the manufacturing method, there are two methods, one is using limestone, which is obtained by adding various additives to limestone at high temperature, as the raw material, and the other is using commercially available quick lime.The former has high production cost and the latter has stable product performance. Lack sex.

[Object of the Invention] An object of the present invention is to provide a crushing agent which improves the above-mentioned drawbacks caused by quick lime and exhibits a stable and excellent effect.

[Problems to be Solved by the Invention] The quick lime used as a crushing agent is generally hard-baked quick lime with a slow hydration reaction, but the burning degree of commercially available hard-baked quick lime is unstable. The soft-calcined quick lime part with fast hydration reaction is mixed, and the activity value (10 min value of 100 g method in the reference test method of Japan Lime Association) is 20 to 50 even in the same lot.
It is an aggregate of particles with a nonuniform firing degree with a difference of 0 ml. Since the particles of soft-calcined quick lime are softer than those of hard-calcined quick lime, when the hard-calcined quick lime raw material is crushed in the ball mill, the soft-calcined quick lime particles are over-crushed, so the crushing agent When used as a raw material, the hydration reaction of soft-baked quicklime powder is extremely fast, and the heat of hydration at that time also accelerates the hydration reaction of hard-baked quicklime powder, so it is difficult to adjust the hydration reaction rate. It is what

[Means for Solving the Problems] The present invention is to remove the soft-calcined quick lime mixed in the block-shaped hard-calcined quick-lime raw material and use the hard-calcined quick-lime only as the main raw material.

That is, using so-called hard-baked quick lime obtained by burning lump-shaped quick lime at 1,300 to 1,500 ° C as a raw material, hard-baked quick lime particles and soft-baked quick lime particles are selected by utilizing the difference in color and grindability,
Only hard-calcined lime is taken out, and as a method, (1) Paying attention to the fact that soft-calcined lime particles are softer than those of hard-calcined. ~
Particles passing through a 5 mm sieve are removed.

(2) Focusing on the fact that soft-calcined quick lime particles have a whiter color than hard ones, remove relatively white-colored particles from the hard-calcined quick lime particles.

(3) Focusing on the fact that the hard-calcined quick lime particles are darker in color (developed) than soft-calcined particles, only the relatively dark-colored particles are taken out of the hard-burnt quick lime.

The above three methods can be mentioned. The hard burned lime raw material used in the above operation preferably has a fractional activity value of 250 ml or less. This is because the efficiency of the above operation deteriorates.

Regardless of which of the above three methods, quick lime that has undergone the operation has a smaller range of fluctuation in activity than hard-baked quick lime before the operation, and the hydration reaction of the crushed product that is the crushed product Stabilize the speed.

The quicklime obtained by the above-mentioned operation has a specific surface area (Blaine method) of 15
It is crushed to 00 to 4000 cm ² / g, and added to 100 parts by weight of the pulverized product in an amount of 0.3 to 8 parts by weight of a water reducing agent, 0.2 to 7 parts by weight of gypsum, and 0 to 70 parts by weight of admixture, and mixed. Obtain the desired crushing agent. A crushing agent depending on the use temperature and the pore size is obtained by adjusting the above-mentioned composition.

The fineness of the pulverized material has a great influence on the performance of the pulverizing agent, and the fineness of the pulverized material is high, that is, the pulverizing agent obtained by finely pulverizing has a relatively fast hydration reaction, and when the aqueous slurry is formed, the pulverized material is pierced. There is a risk of bumping due to heat generation because the time to maintain fluidity enough to fill the pores (pot life) is short and the hydration reaction is fast. The pulverized product has a low fineness, that is, a pulverizing agent obtained by coarsely pulverizing has a relatively slow hydration reaction,
After the filling of the material to be crushed into the pores as an aqueous slurry, the expansion pressure is slow to develop, and the time until crushing becomes long, which is unsuitable. Therefore, the fineness of quicklime in the present invention preferably has a specific surface area of 1500 to 4000 cm ² / g.

As the water reducing agent, any commercially available water reducing agent for cement can be used, but a so-called high performance water reducing agent is particularly preferable. When this high-performance water reducing agent is used, when the crushing agent is made into an aqueous slurry, it is possible to reduce the mixing ratio of water and the crushing agent and it is effective not only for the expansive expression,
It delays the hydration reaction of the aqueous slurry and has an appropriate pot life. An appropriate amount of addition is 0.3 to 8 parts by weight (relative to 100 parts by weight of hard-baked lime particles) in order to suppress the hydration reaction of the crushing agent slurry and delay the development of its expansion pressure as it increases. .

Gypsum is used as a retarder for the hydration reaction of the crushing agent, and any anhydrous, half-water or dihydrate gypsum can be used because it has a retarding effect. Although the hydration reaction of quicklime powder can be suppressed by the water reducing agent as described above, gypsum suppresses the hydration reaction of the crushing agent slurry without reducing the expansion pressure as compared with the water reducing agent. The appropriate addition amount is 0.2 to 7 parts by weight with respect to 100 parts by weight of hard-baked lime powder.

For the mixed material, the hydration reaction of the crushing agent slurry cannot be controlled with a water reducing agent or gypsum when the temperature of the crushing agent is high, such as in spring, autumn, or summer, or when the pore size to be used is large. It is added to reduce the quicklime content in the crushing agent and to reduce and control the amount of hydration reaction. The addition of a cheaper admixture compared to quicklime can significantly reduce the production cost of crushing agents than the addition of relatively expensive agents (water reducing agents, retarders, etc.) to regulate the hydration reaction. . As the mixing material, quick lime filler, silica stone powder, slag powder, fly ash, etc. can be used, but the fluidity of the crushing agent slurry is improved, it has an appropriate hydration reaction delaying action, and it is not necessary to crush, etc. The use of fly ash is preferred. Moreover, the pulverizing agent to which fly ash is added has an effect of reducing the risk of bumping phenomenon by condensing after filling the slurry. The blending amount varies depending on the temperature of the crushed object, the pore size, etc., but an appropriate range is 0 to 70 parts by weight with respect to 100 parts by weight of the hard burned lime powder.

As described above, in the present invention, the rate of the hydration reaction of quick lime is stabilized by removing the soft burn quick lime particles in the hard burn quick lime raw material, depending on the temperature and the pore diameter of the crushed object, the fineness of the quick lime, The desired crushing agent is obtained by adjusting the addition amount of the water reducing agent and the retarding agent and the blending amount of the mixed material.

[Operation] Since the present invention has the above-mentioned constitution, the crushing agent of the present invention 1
20 to 40 parts by weight of water may be added to 00 parts by weight and a kneaded slurry may be poured into the holes formed in the brittle object, and the brittle object may be crushed by using the expansion due to the hydration reaction of quicklime when left standing. it can. The time required from injection to crushing is usually 10 ~
Although it is 24 hours, it is necessary to consider the hole diameter and temperature of the crushed object.

[Examples] (A) A block of hard-calcined quicklime material (activity test of shrunk samples-250 ml or less at 10-minute value) was crushed to a particle size of 10 mm sieve, and sieved under 1-5 mm of it. And grind.

(B) The lump-shaped hard-calcined lime raw material (the same as in A above) is crushed by removing the relatively white-colored particles.

(C) Only relatively black particles are taken out from the hard-baked lime raw material in (A) above and crushed. Above (A), (B)
, (C) Melment (Showa Denko) as a water reducing agent for 100 parts by weight of hard-calcined quicklime powder obtained by either method.
0.3 to 8 parts by weight, 0.2 to 7 parts by weight of anhydrous gypsum, and 0 to 70 parts by weight of fly ash are added and mixed to obtain a target powder.

(1) Test method for crushing agent performance confirmation a. Measurement of expansion pressure JIS G 3454 Carbon steel pipe for pressure piping 40 ASCH 80 was cut into a length of 30 cm, paper strain gauges were attached at two locations in the outer peripheral direction of the pipe, and the conversion factor of internal pressure due to external strain was calculated by hydraulic pressure. After that, attach a bottom lid to one end of the pipe, stand upright with the opening up and put it in a container containing a predetermined amount of water,
Put the crushing agent from the opening of the pipe into a container containing a predetermined amount of water, fill the slurry kneaded with the predetermined water of the crushing agent from the opening of the pipe, and measure the static strain of the pipe over time. The expansion pressure (Kgf / cm ² ) is calculated by the coefficient of.

At this time, the temperature of the outer wall of the pipe is also measured. As a crushing agent for small holes (φ35 to 50 mm) of brittle materials, the expansion pressure after 24 hours is 250
It is desirable that the temperature rise due to heat generation is 10 ° C or less at Kgf / cm ² or more.

b. Stability of commercially available quicklime Quickly burned quicklime produced by a continuous firing method at a firing zone temperature of 1,300 to 1,500 ° C is used for the above-mentioned (A), (B), (C).
Those that have been sorted by each method and those that are not sorted (no sorting)
The activity value (reduced sample-10 minutes value) of
It was as shown in the table.

Example 1 The raw materials of sample Nos. 1 to 4 in the above Table 1 were crushed as shown in Table 2, and 100 parts by weight of the powder thus obtained are shown in Table 2 with Melment (supra) and CaSO ₄ . A crushing agent was obtained by adding in a ratio and homogenizing. The expansion pressure of the slurry obtained by kneading 100 parts by weight of the obtained crushing agent at a ratio of 30 parts by weight of water was measured in a thermostatic chamber at 5 ° C. The results are shown in Table 2.

Example 2 The raw materials of Samples No. 1 to No. 4 in Table 1 were pulverized as shown in Table 3, and 100 parts by weight of the obtained powder was mixed with Melment (described above) and CaSO ₄ . Fly ash third
The ingredients were added in the proportions shown in the table and homogenized to obtain a crushing agent. The expansion pressure of the slurry obtained by adding 30 parts by weight of water to 100 parts by weight of the obtained crushing agent and kneading was measured in a thermostatic chamber at 20 ° C. The results are shown in Table 3.

Example 3 The raw materials of the above-mentioned sample Nos. 1 to 4 were pulverized as shown in Table 4, and 100 parts by weight of the obtained powder was used to display Melment (described above), CaSO _4, and fly ash. A crushing agent was obtained by adding and homogenizing at a medium ratio. Table 4 shows the results of measuring the expansion pressure of a slurry obtained by kneading by adding 30 parts by weight of water to 100 parts by weight of this product in a thermostatic chamber at 30 ° C.

In Test 13 in the table, the bumping phenomenon occurred twice, the maximum temperature was high, and it was dangerous and unsuitable as a crushing agent.

Example 4 Specimens made of unreinforced concrete (600 mm × 600 mm × 600 mm, material cooling 33 days, compressive strength 315 Kgf / cm ² , tensile strength 24 Kgf / c
A hole (hole diameter 38 mm, depth 550 mm) was formed in the center of the upper surface of m ² ). This test sample was placed in a thermostatic chamber at 20 ° C. (± 2 ° C.) for 1 week, and then 30 parts by weight of water was added to the holes in 100 parts by weight of the crushing agent shown in Table 3, Test No. 12 of Example 2. A slurry obtained by mixing was filled and a crushing test was performed.

About 11 hours after filling the slurry, cracks were generated in the upper surface pores of the test piece, and after about 22 hours, the crack width was divided into 5 to 25 mm from the upper portion to the lower portion, and the specimen was divided.

[Effect] In the present invention, a crushing agent is produced by using only the hard-calcined quick lime part obtained by removing the soft-calcined quick lime part contained therein, which is obtained by baking massive limestone. The agent is mainly composed of this hard-baked quicklime. This is inexpensive and has stable performance.

There are roughly two types of quicklime used in the production of crushing agents, one of which is powdered limestone containing impurities (SiO ₂ , F
e ₂ O ₃ , Al ₂ O ₃ etc.) is added and calcined to obtain quick lime with a uniform and stable hydration reaction rate, and the quick lime is used as a crushing agent. The quick lime obtained by firing coarsely crushed massive limestone at a relatively high temperature of 1,300 to 1,500 ℃ is used. The former quick lime has stable hydration reactivity, but its manufacturing cost is very high. The latter, quick lime, is inexpensive to produce and requires various operations (such as adding chemicals and water when crushing quick lime) when using quick lime as a crushing agent.

In the present invention, the latter quicklime stabilizes its hydration reactivity in a simple operation and is then pulverized, and a cheap and stable performance is obtained by adding a relatively inexpensive additive or mixing material to each Example. The crushing agent exerts as shown in

Claims (2)

[Claims] 1. A crushing agent containing hard-calcined quick lime as a main component from which soft-calcined quick lime portion contained in a hard-calcined quick lime raw material calcined at 1,300 to 1,500 ° C. is removed. 2. The hard-calcined quick lime after removing the soft-calcined quick lime part is pulverized to a specific area of 1500 to 4000 cm ² / g, and 0.3 to 8 parts by weight of a water-reducing agent and gypsum 0.2 to 100 parts by weight of the hard-baked quick lime. ~
The pulverizing agent according to claim 1, which is composed of a mixed powder of 7 parts by weight and 0 to 70 parts by weight of the mixed material.