JPS6117456A - Manufacture of salt-free aggregate - 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 Field of Application The present invention relates to a method for producing salt-free aggregate, and its purpose is to produce an aggregate made of so-called crushed sand obtained by crushing natural rock, and to process concrete over time. A salt-free aggregate production method that can provide aggregate that does not contain any salt that causes deterioration and disintegration, and in addition has extremely low content of washing loss (0,074 mm sieve pass powder) that causes concrete strength deterioration. It is provided by.

Conventional techniques and their disadvantages In general, crushed sand (aggregate obtained by crushing natural rock) is usually highly alkaline, and concrete walls constructed using such alkaline aggregates deteriorate over time and collapse. In recent years, it has become a major social problem.

In other words, concrete walls constructed using basic mountain sand with a high alkaline content in the aggregate mixed as an filler for cement materials will stop cracking after about 10 to 15 years.
Accidents of the inner walls of buildings and tunnels collapsing easily have occurred repeatedly, and this has become a social problem.

However, since there are restrictions on the extraction of natural river sand and sea sand, it is often necessary to procure aggregate from mountain sand. It often contains salt (basic sand with a high alkaline content), making unsalted natural sand extremely rare and in extremely limited supply.

Therefore, salt-free crushed sand is desired in the industry.
At present, salt-free crushed sand has not been completed.

However, there have been attempts to produce salt-free crushed sand.

For example, acidic or neutral natural rocks with high silicic acid content, such as cuckoo rock and rhyolite, or neutral rocks such as silicate rock and succulent rock, are dug down, and this natural rock is first roughly crushed. The proposed technology involves adjusting the rough crushing and then finely crushing the rock to produce salt-free mountain sand.

However, the crushed sand produced by this trial technique inevitably contained a large amount of washing loss (powder with a sieve pass of 0,074 mm), and fibrous of desirable quality could not be obtained.

Concrete walls constructed using aggregate with a high content of washing loss (powder at a sieve pass of 0,074 mm) are problematic because the particles corresponding to this washing loss deteriorate the strength of the concrete wall. Ta.

On the other hand, this washing loss (powder of 0,074 mm sieve pass)
In an attempt to remove the content 9 in advance, the finely crushed rock is washed with running water, and the finely crushed stone is classified and used as aggregate.
Now improve the strength of concrete walls 0, 3 to 0
．． The aggregate did not contain sand equivalent to a sieve size of 15 mm, and this aggregate was also not desirable.

Therefore, in order to improve the crushed sand bone facies by this proposed method, the finely crushed rock was washed and classified with running water, and then 0.3 m
There is also a method of adding natural river sand or natural sea sand equivalent to a sieve size of 0.15 mm to 0.15 mm to produce a bone phase in which each particle size is distributed in a suitable distribution, but this improvement method Even if the rock to be used is acidic or neutral, the salted sand will be mixed in from the natural sand that is added at the end, making it impossible to obtain a salt-free aggregate.

(Solution Means) This invention was made to solve the above-mentioned drawbacks of the prior art, namely, it does not contain basic sand and has a uniform particle size distribution from the 5 mm sieve to the 0.15 mm sieve pass. This method has been completed to produce crushed sand bone phase that meets the JISA 5005 Class 1 regulations.

That is, in this invention, an acidic or neutral natural rock with a high silicic acid content is excavated, the natural rock is first coarsely crushed into a particle shape of approximately 150 mm sieve pass, and the coarsely crushed rock is Finely pulverize the stone to adjust the particle size to a 5mm sieve pass, then use an air classifier to remove the powder with a 0.074mm sieve pass, resulting in a particle size distribution of 98% from 5mm to 0.074mm sieve pass. The present invention relates to a method for producing salt-free aggregate that includes the above adjustments.

(Example ) An embodiment of this invention method will be described in detail below.

The acidic or neutral natural rocks with high silicic acid (Si02) content used in this invention include granite, andesite,
In this invention, basic rocks such as basalt are not used.

This type of rock is excavated in a rocky area, and before excavation, the adhering soil such as sand is washed away with water.

The washed rock is further crushed with a crusher and the particle size is adjusted to a sieve pass of 150 mm using a vibrating sieve.

(7) In order to adjust the particle size to 1501 sieve mesh passes, the pulverizing step of crushing with the crusher and the step of classifying with the vibrating sieve are repeated.

In addition, water may be added in the crushing process if necessary to avoid heating the crusher.

Next, the pulverization sound obtained by rough pulverization with the particle size adjusted to a sieve pass of 150 mm is stored or finely pulverized without storage. This fine grinding is performed with the aim of passing through a 5 mm sieve.

This pulverizer is designed to supply hot air into the device (
A ball mill (Erfort type mill), which grinds with steel balls (while drying the wet coarse grinding), is preferably used, but it is not necessarily limited to this.

In addition, the fine powder generated during this grinding is removed using a cyclone, etc.
．． This fine powder is collected and used for Ichihara and asphalt addition.

This finely crushed stone is passed through a 5 mm sieve using a vibrating sieve.

The crushed stone with a sieve size of 5 mm is again subjected to a fine crushing process.

Next, this finely crushed stone is passed through an air classifier to 0°074
Remove powder with sieve pass of mm, 5 questions to 0.074 mm
Adjust the accuracy distribution of sieve mesh to 98% or more.

In the method of this invention, this step is the most important step, and there is currently no equipment that can efficiently remove powder with a sieve pass of <0.074 mm. ) This technology overturns the conventional wisdom that dry type classification equipment must be used in chemical factories. It was believed that highly precise and dust-free dry classification equipment could not be used in processes such as civil engineering work because it would not improve work efficiency.

However, as mentioned above, in a wet classifier, the 0.0
Not only the powder from the 74 mm sieve pass but also crushed sand with a particle size of 0.3 mm to 0.074 mm, which affects concrete strength, was washed away.

The dry classifier shown in Figure 1 is an air classifier created by this inventor and is suitable for rough work processes such as civil engineering work.
In addition, it has good workability (only the powder passing through the 0.074 mm sieve can be reliably removed).

Hereinafter, the air classifier t1 shown in FIG. ) However, the method of this invention is not necessarily limited to this air classifier, and other air classifiers may be used as well. All can be used as long as they have a suitable structure.

In Fig. 1, (2) is a crushed sand inlet, (3) is a rotating drum, and (4) is a spirally planted hole on the inner wall of this drum (3), either continuously or at angular intervals. It is a thread or a feather.

(5) is the crushed sand outlet, (6) is the compressed air outlet, (
7) is air delivery [ ], (8) is cyclone, (9)
is a bald filter, 00) is a vacuum pump, (11) is the suction port of this vacuum pump 00), and (12) is a combination filter.

In order to carry out the classification process according to the present invention using the air classifier (11) having such a configuration, firstly, crushed stone with a 5 mm sieve pass is introduced through the crushed sand inlet (2), and the drum (3) is ).

At the same time, the vacuum pump (1ψ) is operated to send compressed air into the tram (3), and at the same time, the air inside the tram (3) is sucked through the bald filter (9) and the cyclone (8).

At this time, the rotational speed of the drum (3) for compressed air pressure and suction pressure is appropriately selected and set to conditions that can reliably remove only the powder in the sieve pass of 0.074 mm.

The crushed sand is stirred by the threads or blades (4) in the drum (3) and moves inside the drum (3) toward the crushed sand outlet (5). ) is discharged outside.

Fine powder with a 0.074 mm sieve pass is filtered using a bag filter (
9) and cyclone (8).

Incidentally, the finely crushed rock collected by the bald filter (9) and the cyclone (8) may be used as an asphalt additive or for seedlings.

The crushed sand discharged from the crushed sand outlet (5) to the outside of the drum (3) does not require a drying process again, and can be used as is by being mixed into mortar as a salt-free aggregate.

Effects of the Invention As detailed above, the method for producing salt-free aggregate according to the present invention involves digging up acidic or neutral natural rocks with a high content of poric acid,
This natural rock is first coarsely crushed to a grain size of about 150mm sieve pass, and the coarsely crushed rock is finely crushed to a size of 150mm.
The particle size is adjusted to m sieve pass, and then the finely crushed stone is removed by an air classifier to remove the powder of 0.074 mm sieve pass, and the particle size distribution is adjusted to 98% or more from 5 mm to 0.074 mm sieve pass. Since it is a salt-free aggregate production method that consists of the following, it has the following effects.

(]l So-called crushed sand obtained by crushing natural rocks,
Furthermore, aggregates containing no basic sand can be produced.

(2) Therefore, this aggregate is a bone phase that does not cause concrete to deteriorate and collapse over time.

(3) The content of washing loss (powder of 0,074 mm sieve pass) that causes concrete strength deterioration is extremely low.
JIS standard 1 including grain size of mm to 0.074mm sieve mesh
It becomes the aggregate that passes the grade.

(4) Good workability and suitable for mass production.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an air classifier used in one embodiment of the method of this invention. (11-Air classifier Figure 1

Claims (1)

[Claims] (1) Acidic or neutral natural rock with a high silicic acid content is dug up, and this natural rock is first coarsely crushed into a particle shape of approximately 150 mm sieve pass, and the coarsely crushed rock is finely crushed. The finely crushed stone is then used in an air classifier to remove the powder with a 0.074 mm sieve pass, resulting in a particle size distribution of 5 mm to 0.074 mm sieve pass of 98% or more. A salt-free aggregate production method consisting of conditioning.