JP2000044303A - Production of artificial aggregate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain artificial aggregate at a low cost under a condition of comparatively low energy consumption by adding steelmaking and refinery slag powder including high alkali such as blast-furnace slag and water to fly ash by kneading the mixture, granulating it and curing it through steam curing or warm water curing. SOLUTION: This artificial aggregate, in which fly ash is bound together with slag powder hydrates as a binder, the equal hardness is given and the grain size is uniform, is obtained by adding steelmaking and refinery slag powder to fly ash, kneading the mixture, granulating it and curing it. The fly ash is ground granulated one exhausted in burning coal and having <=100 μm particle diameter, and includes 70-85 wt.% main ingredient comprising silica and alumina as the main constituent and a small quantity of Fe2O3, CaO, MgO and a trace of minerals. The steelmaking and refinery slag powder is prepared by quenching liquid slag discharged from a blast furnace with water, etc., and by size control, has 0.3-5 mm particle diameter, includes CaO as the main constituent and SiO2, Al2O3, etc., and has latent high hydraulicity due to high lime aluminosilicate glassy state.

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 an artificial aggregate using combustion ash such as fly ash and bottom ash produced as a by-product during coal combustion.

[0002]

2. Description of the Related Art Recently, with the shortage of natural aggregates, development of alternative aggregates has been desired. Among them, the most noticeable is combustion ash by-produced during the combustion of coal used as boiler fuel. For example, electric power companies are currently struggling with the disposal of combustion ash,
If the above-mentioned combustion ash can be used to regenerate the aggregate, both the problem of discarding the combustion ash and the problem of the shortage of the aggregate can be solved.

[0003] The rate of generation of combustion ash is 5 to 15 sand clinker ash (bottom ash) similar to fine sand.
%, Fine-grained fly ash is 85 to 95%, and fly ash occupies most of it.
Silica and alumina account for 70-80% of the whole,
All are the same as natural mud components.

[0004] Therefore, a method for regenerating the combustion ash into aggregate is as follows.
It has been done by various research institutions. The manufacturing methods can be broadly divided into fly ash alone or a method in which other natural or artificial minerals are mixed and baked and solidified to form a lightweight aggregate, and fly ash is mixed with cement and granulated to form fine aggregate. There are two types of methods.

[0005]

However, in the former manufacturing method, a firing step is required, and a large heating energy is required. In addition, the latter production method requires the addition of cement, which results in high costs and has a problem in terms of profitability. From this point of view, recently, a method of pulverizing and classifying the bottom ash alone and processing it into fine aggregate has been adopted, but as described above, the ratio as a by-product is low, and the quantity is secured. In addition, it is difficult, and in the classification process for making the particle size distribution uniform, the yield is reduced, which is also problematic in terms of profitability.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for producing an artificial aggregate which is relatively low-energy and inexpensive and can be easily granulated. .

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a method of kneading fly ash by adding steelmaking containing high alkali such as blast furnace slag, refining slag powder, and water. After the granulation, curing is performed by steam curing or hot water curing.

The "steel making and smelting slag powder" referred to in the present invention is a slag containing a large amount of calcium produced as a by-product in a blast furnace or the like, and can be used alone as a fine aggregate. It is soluble in water and has latent hydraulic properties. By mixing with coal ash, it functions as a binder that binds coal ash.

Therefore, according to the present invention, an artificial aggregate can be produced by the same principle mechanism as that of the conventional cement mixing method, and the slag powder itself can be obtained at extremely low cost and constantly as a blast furnace by-product. Therefore, the manufacturing cost can be reduced.

Further, in the present invention, steelmaking containing high alkali such as blast furnace slag, coarse and fine aggregates of refining slag, and water are added to fly ash, and the mixture is kneaded and granulated, and then steam cured or steam cured. After curing by warm water curing, or by adding high alkali powder such as blast furnace slag and water to the particles obtained by pulverizing the bottom ash, kneading and granulating, the particles can be cured by steam curing or warm water curing.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION (1) The first invention relates to a steelmaking method in which fly ash contains high alkali such as blast furnace slag,
After refining slag powder and water are added, kneaded, granulated, and cured by steam curing or hot water curing.

The fly ash used in the present invention is in the form of a fine powder having a particle size of 100 μm or less, which is discharged during the combustion of coal. %, Other small amounts of ferric oxide, calcium oxide, magnesium oxide,
Also contains trace minerals.

The steelmaking and smelting slag powder used in the present invention is obtained by rapidly cooling molten slag discharged simultaneously with pig iron from a blast furnace with water or air and adjusting the particle size. 5 mm, and its chemical composition is mainly calcium oxide, contains silicon dioxide, alumina oxide, etc., and has high latent hydraulicity due to its high lime aluminosilicate glass.

The obtained aggregate is microscopically shaped in such a manner that a large number of fly ashes are bound with slag powder hydrate as a binder, has a hardness equivalent to that of a natural fine aggregate, and is formed. The particles have a uniform particle size, and can be used as a fine aggregate that can be sufficiently used.

(2) The second invention provides a fly ash,
After steelmaking containing high alkali such as blast furnace slag, coarse and fine aggregate of refining slag, and water, kneading and mixing, granulation,
It is cured by steam curing or hot water curing.

[0016] The bottom ash used in the present invention has a particle diameter of 0.01 to 0.01 discharged to the furnace bottom during coal combustion.
It is in the form of fine particles of about 1.0 mm, and its components are almost the same as those of fly ash.

The coarse and fine aggregate of steelmaking and smelting slag used in the present invention is, similarly to the above, a crushed slag discharged from a blast furnace at the same time as pig iron by chilling and crushing to adjust the particle size. The chemical composition is almost the same as that of the slag powder.

The obtained aggregate is microscopically opposite to the above, in which slag coarse and fine aggregates are nuclei and a large number of fly ash are bound around the cores. The hardness is equivalent, and the particle size is uniform by granulation.
It can be used as a sufficiently practical fine aggregate.

(3) According to a third aspect of the present invention, high alkali powder such as blast furnace slag and water are added to ground bottom ash particles, mixed with water, granulated, and then cured by steam curing or hot water curing. Things.

The obtained aggregate is microscopically shaped such that bottom ash is bound with slag powder hydrate as a binder, has a hardness equivalent to that of natural fine aggregate, and is granulated by granulation. It has a uniform particle size and can be used as a fine aggregate that can be practically used.

In the above embodiment, granulation is performed by combining fly ash, bottom ash alone and slag powder, or slag coarse and fine aggregate, but slag is added to a mixture of fly ash and bottom ash. Needless to say, powder may be combined.

Further, in any of the inventions, in addition to the above components, calcium hydroxide or sodium hydroxide is added to water in advance to form an alkaline solution, whereby the hydration reaction of the slag powder is performed. Can be promoted.

As the granulator used for kneading, a van pelletizer, a drum granulator, and other known granulators can be used. After the granulation, the particles discharged from the container are laid out in a steam curing room or a hot water curing room and steam cured or hot water cured. After the curing is completed, the product is weighed and packed in a bag or, if necessary, classified by a sieve and bagged according to the particle size distribution to obtain a product.

[0024]

As is apparent from the above description, in the method for producing an artificial aggregate according to the present invention, as compared with the conventional method of granulating cement using a binder, all of the materials are made of waste materials. Therefore, since it is only necessary to perform steam curing or hot water curing after granulation, it does not require a large amount of energy as compared with the firing method, and can be produced at lower cost.

Claims (3)

[Claims] 1. A method in which fly ash is mixed with steel containing high alkali such as blast furnace slag, refined slag powder, and water, kneaded and granulated, and then cured by steam curing or hot water curing. A method for producing an artificial aggregate. 2. Addition of steel containing high alkali such as blast furnace slag, coarse and fine aggregate of smelting slag, and water to fly ash, kneading and granulation, and curing by steam curing or hot water curing. A method for producing an artificial aggregate. 3. An artificial bone characterized by adding high alkali powder such as blast furnace slag and water to ground ash ground particles, kneading and granulating the mixture, and then hardening by steam curing or hot water curing. The method of manufacturing the material.