JPH0735279B2 - Water absorption cooling method of artificial lightweight aggregate - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water absorption cooling method for artificial lightweight aggregate.

2. Description of the Related Art Conventionally, a lightweight aggregate has been artificially manufactured using fly ash generated from coal-fired thermal power generation facilities, shale rock, cinder, and blast furnace slag as main raw materials.

In the production of such an artificial lightweight aggregate, conventionally, an aggregate raw material such as fly ash is granulated by a granulator, and the granulated product (raw pellet) is calcined in a calcining furnace, and the calcined granulated product is manufactured. After air cooling with a cooler kiln, remove it from the firing furnace, then pre-wetting (pre-water absorption) by means such as immersion in normal temperature water outside the firing furnace, water sprinkling with a sprinkler to stabilize the water absorption rate to about 20-25%. Manufactured artificial lightweight aggregate.

It should be noted that such pre-wetting stabilizes workability after mixing with cement and water, particularly when using an artificial lightweight aggregate as coarse aggregate or fine aggregate of lightweight concrete, especially for a pump. To ensure pumpability,
It is essential in the manufacture of artificial lightweight aggregates.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, in the prior art, prewetting of the artificial lightweight aggregate is performed by means such as immersion in normal temperature water outside the firing furnace, water sprinkling by a sprinkler, or the like, and the amount is about 20 to 25. %
Since we have obtained lightweight aggregate that has absorbed water, this pre-wetting is usually involved for 3 to 4 days, so we need a sprinkler and other sprinklers for pre-wetting, which is 3 to 4 times the production capacity. I was trying.

Means for Solving the Problem The present invention, in order to solve such conventional problems, the granulated material of aggregate raw material such as fly ash is fired, and then rapidly absorbed water after cooling to 600 to 200 ° C. It is designed to be cooled.

Action With such rapid water absorption cooling, pre-wetting is performed for about 5 minutes without causing cracks in the fired granulated product to obtain an artificial lightweight aggregate with a water absorption of about 20 to 25%. be able to.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a system of equipment for producing artificial lightweight aggregate from fly ash by using a firing furnace incorporating means for carrying out the method of absorbing and cooling artificial lightweight aggregate according to the present invention.

In FIG. 1, 1 is a raw material hopper for storing fly ash 2 generated from a coal-fired thermal power generation facility, 3 is a water hopper for storing water 4, and 5 is a binder (including a combustible carbon material such as pulverized coal). It is a binder hopper for storing 6.

Then, the fly ash 2 discharged from the raw material hopper 1 is added with an appropriate amount of the water 4 and the binder 6 discharged from the hoppers 3 and 5, respectively, and introduced into the humidifying and kneading machine 7, where they are sufficiently kneaded. It is supplied to the pan type granulator 8 and granulated while being sprinkled with water.

The fly ash granules are then fed to the roller screen 9 and the granules with a predetermined particle size (usually 5 to 20 mm) are placed in a closed firing furnace 10 while larger than the predetermined particle size or The small granules are returned to the kneader 7 through the return line 11.

The granulated product 12 having a predetermined particle size, which has been put into the firing furnace 10, is laminated on a grade (lattice hearth), dried, preheated, and then landing device.
At the same time as being ignited by 13, the blower 15 sucks air from the suction box 14 at the bottom of the grade, and the air is circulated through the line 16.

As a result, in the granulated material 12, the carbon contained in the fly ash is burned, and the temperature is higher than the melting temperature of the fly ash.
The temperature is raised to about 1000 to 1200 ° C., which is lower by 50 to 100 ° C., baked for a predetermined time, and then moved to the cooling zone 17.

The calcined granulated material 12 that has entered this cooling zone is gradually cooled by the fresh air blown from above through the line 18. In this case, according to the present invention, the calcined granulated material 12 is 60
When the temperature falls to 0 to 200 ° C., for example, water or steam is instantaneously jetted from above through the line 19, and the granules 12 are
In the hot state, water is rapidly absorbed and cooled. It is preferable to provide a partition plate 21 for partitioning the water absorption zone 20 from the cooling zone 17.

However, such rapid water absorption cooling is better as the temperature of the granulated product is higher, but if it is too high, cracks will occur in the granulated product. Therefore, according to the present invention, as described above, the granulated product is cracked. Is gradually cooled in the cooling zone of the firing furnace, and when it falls to 600 to 200 ° C, rapid water absorption cooling is performed.

FIG. 2 shows the relationship between the water absorption rate and the temperature of the artificial lightweight aggregate obtained by such rapid water absorption cooling according to the present invention.

In Fig. 2, the solid line indicates the water absorption rate after the rapid water absorption cooling of the fly ash granules for 5 minutes, which is 500 ° C.
It was 25% at 23 ° C, 23% at 300 ° C and 20% at 200 ° C, and cracks occurred at temperatures above 600 ° C and near 700 ° C. The alternate long and short dash line shows the water absorption rate after rapid water absorption cooling of the granules of shale for 5 minutes, and the results were almost the same as those of the granules of fly ash at 200 to 700 ° C.

In FIG. 1, the granulated product 12 after cooling with water absorption is the firing furnace.
Emitted from 10 and then, as is well known, grizzly,
The particles are sized with a crusher and a screen to become an artificial lightweight aggregate.

Further, in the present embodiment, rapid water absorption cooling of the granulated material 12 is performed by injecting water or steam at the end of the cooling step in the firing furnace 10, but is not limited to this.
Such rapid water absorption cooling can also be performed outside the firing furnace by means such as immersion in water or water sprinkling.

Further, in the present embodiment, the closed type firing furnace 10 was used,
Since only the amount of O ₂ in the atmosphere is different from the atmosphere open type firing furnace, the atmosphere open type firing furnace can also be used by controlling the quenching temperature.

Effects of the Invention As described in detail above, according to the present invention, a granulated material of an aggregate raw material such as fly ash is fired, and then 600 to 200 ° C.
By rapidly cooling with water after cooling to 50%, pre-wetting is performed for about 5 minutes without cracking the fired granules to obtain an artificial lightweight aggregate with a water absorption rate of about 20-25%. You can The artificial lightweight aggregate manufactured in this way is less likely to evaporate the water inside it than it would be if it were left to stand naturally, so the pre-wetting time before the construction of lightweight concrete can be greatly reduced, and workability is improved. Is improved.

In addition, as shown in the examples, by performing rapid water absorption cooling of the fired granulated product at the end of the cooling process in the firing furnace, prewetting for 3 to 4 times the production capacity is performed. No storage is required and equipment such as sprinklers for watering can be omitted.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example of manufacturing an artificial lightweight aggregate from fly ash by using a firing furnace incorporating a means for carrying out the method for absorbing and cooling artificial lightweight aggregate according to the present invention.
The figure is a diagram showing the relationship between the water absorption rate and the temperature of fly ash and shale artificial lightweight aggregates obtained by rapid water absorption cooling according to the present invention. 1 ... Raw material hopper, 2 ... Fly ash, 3 ... Water hopper, 4 ... Water, 5 ... Binder hopper, 6 ... Binder, 7 ... Humidifying and kneading machine, 8 ... Bread granulator, 9 ...
… Roller screen, 10 …… Burning furnace, 11 …… Granulate return line, 12 …… Granulate, 13 …… Ignition device, 14 …… Suction box, 15 …… Blower, 16 …… Air supply line, 17 ……
Cooling zone, 18 ... air supply line, 19 ... water or steam injection line, 20 ... water absorption cooling zone, 21 ... partition plate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiji Nohara 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Works (72) Inventor Shunkuni Sera 2-5 Marunouchi, Chiyoda-ku, Tokyo No. 1 Sanryo Heavy Industry Co., Ltd. (72) Inventor Hideo Take 2-5-14 Minamisuna, Koto-ku, Tokyo Inside the Takenaka Corporation Technical Research Institute (72) Inventor Yasuhiko Yoshioka 2-5 Minamisuna, Koto-ku, Tokyo No. 14 Incorporated Takenaka Engineering Co., Ltd. (72) Inventor Toshio Yonezawa 2-5-14 Minamisuna, Koto-ku, Tokyo Incorporated Takenaka Engineering Co., Ltd.

Claims (1)

[Claims] 1. A method for absorbing and cooling artificial lightweight aggregates, which comprises firing a granulated material of an aggregate raw material such as fly ash, cooling the mixture to 600 to 200 ° C., and then rapidly absorbing and cooling the mixture.