JPS58900B2 - Coarse aggregate for concrete and crushed sand dry manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dry production method for coarse aggregate and crushed sand for concrete, and particularly to a method suitable for producing coarse aggregate and crushed sand of 20 mm or less, which are in extremely large demand.

Generally, when dry-producing coarse aggregate for concrete and crushed sand for concrete at the same time in a factory, a fixed amount of raw stone is supplied to a crusher, and the crushed material is passed through a first sieve to produce coarse aggregate/crushed sand that is equal to or smaller than the product size. At the same time, the crushed materials larger than the product size are returned to the above-mentioned crusher, and the coarse aggregates with the product size or smaller are separated.
The crushed sand is passed through a second sieve to be sieved into product size coarse aggregate and smaller product size aggregate, and the product size coarse aggregate is conveyed to the above-mentioned crusher or product size coarse aggregate storage area via the switching device, and the product size coarse aggregate is transported to the above-mentioned crusher or product size coarse aggregate storage area. The aggregate with dimensions below coarse aggregate is further sieved through a fine sieve to separate crushed sand of product size or smaller and those with larger size.
A method has been adopted in which materials larger than the product size are returned to the second crusher or the above-mentioned crusher, and in this way, coarse aggregate and crushed sand with a particle size as a product are simultaneously produced (for example, in Japanese Patent Laid-Open No. 5
0-61878).

Among the products produced in this way, especially crushed sand, the particles are separated into large and small particles during the transportation process using belt conveyors, etc., or during the storage process, resulting in an uneven particle size distribution. There is a problem.

In other words, it falls during transportation. Natural classification occurs through vibration, and when a cone-shaped pile is formed during storage, large particles tend to roll down to the bottom of the pile. A phenomenon occurs in which the particle size distribution differs between 1 Japanese Industrial Standards (JIS).
It was difficult to maintain the specified quality (particle size distribution) at the time of shipment.

The purpose of the present invention is to eliminate such drawbacks, and its feature is that in the back-side process of coarse aggregate and crushed sand as described above, crushed sand crushed to the particle size as a product is humidified and mixed. It is sent to a machine, humidified, and mixed at the same time, and in this way it is possible to achieve a uniform particle size distribution by preventing mutual movement of particles and avoiding uneven distribution of large and small particles.

The present invention will be explained in more detail below with reference to one drawing.

For convenience of explanation, the following examples are explained in relation to the case where coarse aggregate with a particle size of 5 to 20 mm and crushed sand with a particle size of smaller than that are produced.

Raw stones are supplied from a raw stone bin 1 to a first crusher 3 via a quantitative supply device 2 .

The metering device 2 consists of a controllable belt conveyor, which is advantageous in terms of simplicity and reliability of operation, and also comprises a first crusher 3.
consists of, for example, a cone crusher.

The crushed material from the first crusher 3 is sent to a first sieve 4, preferably constructed as a vibrating sieve, where it is used to crush coarse aggregate/crushed sand of product size or smaller (20 mm or smaller).
The shredded materials are sieved into crushed materials larger than the product size, and the crushed materials larger than the product size are returned to the first crusher 3 via a conveyor 5 such as a belt conveyor and crushed again.

Coarse aggregate/crushed sand of 20 mm or smaller from the first sieve 4 is conveyed to a second sieve 6 configured as a 5 mm vibrating mesh, where it is separated into coarse aggregate with a product size of 5 to 20 mm and crushed sand of smaller size. It is sieved.

The coarse aggregate with a product size of 5 to 20 mm is sent to a switching device 7, which is configured as a switching chute, by means of which the coarse aggregate is returned to the first crusher 3 via conveying devices 8 and 5. Alternatively, the product is delivered to a coarse aggregate storage location 9.

The product size coarse aggregate returned to the first crusher 3 by the switching device 7 is subjected to a granulation effect by rubbing against other crushed stones, mantles, etc. inside the first crusher, and is turned into round, high-quality coarse aggregate. It is forced to change into.

The coarse aggregate sized in this manner is taken out by the switching device 7 in a desired amount to the product coarse aggregate storage area 9.

Crushed sand of 5 mm or less that has been sorted by the second sieve 6 is
The crushed sand is fed onto a third sieve 10 which is integrally constructed with the sieve as a lower sieve, where it is sieved into crushed sand of the product size or smaller and crushed sand larger than the product size. It is fed into the crusher 11 and crushed again.

The second crusher 11 consists of a cage mill, a roll breaker, etc., and these are used depending on the quality of the stone.

In some cases, the first crusher 3 may be used instead.

The crushed sand from the second crusher 11 is partially or completely joined by a second switching device 17 (preferably configured as a chute) with the crushed sand from the third sieve 10 in a merging device 12 (preferably configured as a belt conveyor). (preferably) or
Alternatively, some or all of the water is transported to the humidifying mixer 16 described below before the merging device 12.

The crushed sand from the merging device 12 is delivered to an air classifier 13, where it is classified into fine powder (dust) and particles of larger particle size, and the fine powder is stored in a dust bin 14.

If product crushed sand containing some degree of fines is desired, all or part of the crushed sand from the second crusher 11 is conveyed to the humidifying mixer 16 by the second switching device 17.

The second switching device 17 may be located downstream of the merging device 12.

As mentioned above, according to the present invention, the product crushed sand is stored in the storage location 1.
5, the humidifying mixer 16 is made red and white.

When dry crushed sand is stored, particles with similar particle sizes tend to aggregate (coarse particles and fine particles separate), resulting in an uneven overall distribution. is scattered during storage and transportation, causing a pollution problem.

Conventionally, to deal with the latter problem, a method of sprinkling water on piles of stored crushed sand has been taken, but no equivalent measures have been taken to deal with the former problem.

In view of this point, the present invention proposes to pass the crushed sand from the air classifier 13 through a humidifying mixer 16, and this humidifying mixer 16 preferably consists of a screw mixer, in which the crushed sand is It is moistened to a moisture content of 5-6%.

As described above, according to the present invention, by introducing a humidification mixing step, scattering of crushed sand and non-uniform distribution of particles of different diameters can be prevented, the commercial value of crushed sand can be increased, and the quality of concrete can be improved.

[Brief explanation of drawings]

The drawing is a flowchart showing one embodiment of the present invention. The correspondence relationship between the main parts shown and the symbols is as follows. 3...First crusher, 4...First sieve, 6
...Second sieve, 7...Switching device, 10.
...Third sieve, 13...Air classifier, 9,
14.15... Storage location, 16... Humidifying mixer, 17... Second switching device.

Claims (1)

[Claims] 1. Supply a fixed amount of raw stone to the first crusher, and send the crushed material to the first crusher.
It is sieved to separate coarse aggregate/crushed sand of product size or smaller and crushed material larger than that, and the crushed material larger than the product size is returned to the first crusher, and the coarse aggregate of product size or smaller is sieved.・The crushed sand is passed through a second sieve to be sieved into product-size coarse aggregate and smaller aggregates, and the product-size coarse aggregate is transported to the first crusher or product-size coarse aggregate storage area via the first switching device. , the product size of coarse aggregate or less is passed through a third sieve and separated into crushed sand of product size or less and crushed sand of product size or larger, and the material of product size or larger is fed into the second crusher or the above-mentioned first crusher. , before or after the resulting crushed sand is combined with the crushed sand from the third sieve, a part or all of the crushed sand is sent by a second switching device to an air classifier and/or a humidifying mixer. A coarse aggregate for concrete, characterized in that crushed sand from which dust has been separated by an air classifier is sent to the humidifying mixer, the crushed sand brought there is mixed and moistened, and then transported to a predetermined storage location. Crushed sand dry manufacturing method.