JPH09194251A - Manufacturing method of artificial gravel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing artificial gravel capable of producing the artificial gravel by omitting a granulation stage. SOLUTION: The lumps of raw material mud are dried at >=300 deg.C in a rotary furnace where the lumps of the raw material mud are explosively fissured to small pieces. While the explosively fissured small pieces are rolled in the rotary furnace, the small pieces are dried to form the round dry matter having roundness like that of natural bone materials and the powder pulverized by attrition. After the powder is removed from the small pieces, the small pieces of the dry mud are calcined in the rotary furnace and are sintered, by which the hard artificial gravel having the roundness equiv. to that of river gravel is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing artificial aggregate, artificial gravel such as gravel from inorganic mud such as waste soil from a quarry, construction mud, soil from a water purification plant, and incineration ash.

[0002]

2. Description of the Related Art Conventionally, in the case of producing an artificial aggregate or the like from the above-mentioned inorganic mud, it has been carried out by a granulating step, a drying step and a firing step. At that time, an extrusion molding machine, a dish type granulating machine, a mixer, etc. are used in the granulating step, and an aeration type vibration dryer, a belt type dryer, etc. are used in the drying step, and a baking step is further performed. A rotary furnace, a mobile furnace, etc. are used for this.

In the above-mentioned conventional method, first, in a granulation step, a single or two or more kinds of inorganic mud are mixed and granulated, and the granulated product from the granulation step is dried in a drying step. After being sufficiently dried at a temperature of not higher than ℃, it is baked at 900 to 1200 ℃ in the baking process to manufacture artificial aggregates and the like. In some cases, the drying and firing are performed in a mobile furnace.

[0004]

However, in the above-mentioned conventional method, there is a problem that the artificial gravel is manufactured by each of the steps of granulating, drying and firing, resulting in high cost and no demand.

Therefore, the invention according to claim 1 of the present invention aims to provide a method for producing artificial gravel by omitting the granulation step and producing the artificial gravel at low cost.

[0006]

In order to achieve the above-mentioned object, the method for producing artificial gravel according to claim 1 of the present invention comprises the steps of producing artificial gravel using inorganic mud as a raw material.
It is characterized in that the lump of raw material mud is dried in a rotary furnace at a temperature of 300 ° C or higher and then calcined.

Therefore, according to the first aspect of the present invention, by drying the lump of the raw mud in the rotary furnace, the lump of the raw mud is blasted into small pieces, and the blasted small pieces are transferred in the rotary furnace. As it dries while moving, it has sharpened corners (the sharp corners are worn away) and has a roundness like natural aggregate, and a powder crushed by abrasion. Next, the small pieces of dry mud from which the powder had been removed were fired in a rotary furnace to obtain an artificial gravel that was sintered and hard, and had roundness that did not change from river gravel.

The method for producing artificial gravel according to a second aspect of the present invention is characterized in that, in the structure according to the above-mentioned first aspect, the artificial gravel is dried at a temperature of 300 ° C. or higher in a rotary rotator rotary drying furnace. .

Therefore, according to the second aspect of the present invention, the periphery can be uniformly heated by the rotary rotator rotary drying furnace to improve the yield. The method for producing artificial gravel according to claim 3 of the present invention is characterized in that, in the configuration according to claim 1 described above, the dried product is fired in a rotary furnace in a reducing atmosphere.

Therefore, according to the third aspect of the present invention, by firing in a rotary furnace in a reducing atmosphere, an artificial gravel that has a grayish black appearance, appears to be hard, and is not different from natural aggregate is obtained.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In carrying out the present invention, it was found that when a lump of inorganic mud is rapidly heated at a temperature of 300 ° C. or higher, it explodes to a size of 5 to 30 mm. The cause is that water or crystal water in the inorganic mud is rapidly heated and evaporated. Since the small pieces of the dried mud that have exploded have sharp angles, they have poor workability when used as concrete, and there is a problem that extra cement sand is required. Therefore, it was thought that it is possible to dry the exploded small pieces of dried mud in a horizontal rotary furnace in order to give them a roundness.

Embodiments of the present invention will be described below.
That is, when manufacturing artificial gravel using inorganic mud as a raw material, first, the lump of raw mud is dried in a rotary kiln (rotary furnace) at a temperature of 300 ° C or higher. This drying is
In a rotary kiln (rotary kiln), 300 ℃ or more (300 to 50
It is carried out by introducing a high temperature gas (0 ° C.) and rapidly heating it, and as a result, the lump of the raw mud explodes to 5 to 30 mm. Furthermore, by drying in a rotary kiln, the exploded pieces are dried while rolling, so that the dried product has rounded corners such as natural aggregate with sharp corners (abrasion of sharp corners) and crushed by abrasion. And a powder was obtained.

Then, the small pieces of the dried mud after removing the powder from them were fired in a rotary kiln furnace (rotary furnace) at 900 ° C. (900 to 1100 ° C.) for 1 hour, and then sintered. It is possible to produce artificial gravel that is hard and has a roundness that is not different from river gravel.

Next, another embodiment of the present invention will be described. Based on the prediction that the rotor rotator rotary dryer will improve the yield because it uniformly heats the surroundings of the raw mud agglomerates than the rotary kiln furnace, the mass of the raw mud agglomerates at 400 ℃ in the rotor rotator rotary dryer. As a result of drying with
Blasting of the lumps and abrasion of the sharp corners were performed well, and a roundish dry product was obtained.

Next, still another embodiment of the present invention will be described. The dried product (crushed stone mud) that came out of the rotary furnace was calcined at 900 ℃ for 1 hour in a rotary kiln (rotary furnace) in a reducing atmosphere [oxygen, concentration 1% or less (volume%)], and as a result, ash was obtained. A black, artificially gravel that looked hard on the surface and was no different from natural aggregate was obtained.

When the firing atmosphere was in an oxidized state, it became a brick color, and when it was in a reducing atmosphere, it became black. In each of the above-described embodiments, the baking is performed in the rotary kiln (rotary furnace), but the baking may be performed in the rotary rotator rotary dryer (rotary furnace).

In each of the above-mentioned embodiments, the drying and firing are performed in separate rotary furnaces, but they may be performed in the same rotary furnace. Experimental Example A crushed stone mud having the following physical properties and a diameter of 50 to 100 mm was dried with hot air at 400 ° C. for 20 minutes in a rotary rotator rotary dryer, and as a result, a violent explosion occurred.

Ratio of crushed mud (% by weight) Chemical composition 81.1% Moisture 14.3% Loss on ignition 4.6%

[Table 1] Crushed stone mud True specific gravity (g / cm ³ ) ・ ・ ・ 2.57 Average diameter (μm) ・ ・ ・ 10.58 And the crushed stone mud coming out from the rotary rotator dryer is
The product became roundish like river gravel and became a grayish brown dried product.
This was baked in a rotary kiln at 950 ° C. for 1 hour to obtain artificial gravel. The results of the aggregate test of this artificial gravel are shown below.

Apparent specific gravity 2.33g / cm ³ Water absorption average 10.5% Scraping test average 28.1%

[0020]

According to the first aspect of the present invention described above, it is possible to obtain artificial gravel which is sintered and hard, and has a roundness which is not changed from river gravel and has good workability.
By omitting the granulation step, it can be manufactured and provided at low cost.

According to claim 2 of the present invention described above,
Rotor rotator rotary drying furnace can uniformly heat the surroundings,
The yield can be improved. And claim 3 of the present invention described above
According to the above, by firing in a rotary furnace in a reducing atmosphere, it is possible to obtain artificial gravel that is grayish black and looks hard on appearance and is not different from natural aggregate. Therefore, it is particularly suitable as a landscaping material (ball gravel). Can provide colorful artificial gravel.

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Claims (3)

[Claims] 1. When producing artificial gravel using inorganic mud as a raw material, a lump of raw mud is dried in a rotary furnace at a temperature of 300 ° C. or higher and then fired. Production method. 2. The method for producing artificial gravel according to claim 1, which is dried at a temperature of 300 ° C. or higher in a rotary rotator rotary drying furnace. 3. The method for producing artificial gravel according to claim 1, wherein the dried product is fired in a rotary furnace in a reducing atmosphere.