JPH06345511A - Compact with fine quartz sand powder as aggregate - Google Patents

Abstract

(57) [Summary] [Purpose] There was no choice but to dump it as industrial waste.
Bread (including fine silica sand powder) that is dust collected when reclaiming foundry sand
Reuse as a raw material, mix with other materials and mold into molded products to provide products for various applications. [Structure] The aggregate is mainly composed of silica sand fine powder, and the aggregate 1
40 to 80% by weight of cement with respect to 00, and 25 to 60% by weight of water relative to the cement are kneaded to form a mixture,
It is made into a compact by a molding machine. As a compounding material, coal powder, cement admixture, iron oxide, or the like may be added depending on the use of the molded body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as a molded body of dust collecting dust and fine silica sand powder generated when industrial sand is reclaimed, and its application field is a stepping stone on a sidewalk, a flower pot, or coloring. Regarding making bricks etc.

[0002]

2. Description of the Related Art Dust collecting dust and fine silica sand powder generated when reclaiming foundry sand are fine powders having a particle size coefficient S _n = 620 level. Most of this fine powder must be disposed of as industrial waste for landfill.

Generally, powder is applied to various uses as a molded body, and as a molding machine for forming a powder mixture, a powder molded body such as a refractory or a tile for building materials is molded. Vibration press molding machine "(JP-A-61-250)
No. 8) is disclosed. In this molding machine, a vibrator and a pressurizing cylinder are arranged and supported on the molding table side and the press platen side, respectively, and the upper and lower two sets of these are relatively related to each other so that the powder raw material can be evenly distributed. It is said that vibration press molding will be possible. And its composition,
The action (see Fig. 3) is a small capacity lower hydraulic cylinder 8
Has its lower end fixed to the center of the press base 7 for vertical support, and a lower vibrator 9 fixedly supported on the lower surface of the center of the molding base 17. An upper vibrator 13 that is fixedly supported is provided on the central upper surface of the push plate 12,
The large-capacity upper hydraulic cylinder 16 is vertically supported with its lower end fixed to the center of the upper fixed girder 15. These two sets of vibrators and pressure cylinders, which are upper and lower, work relatively in relation to each other, and uniform vibration force and pressure are always organically exerted on the upper, lower, left and right sides of the inside of the powder. It is possible to deal with press molding of powder with a uniform pressure distribution inside the powder without causing unevenness, and even with complicated shapes, molded products with uniform filling degree and tightness can be formed. I'm supposed to.

[0004]

The fine silica sand powder generated when the foundry sand is reclaimed is disposed of as industrial waste for landfill. In recent years, the amount of waste from households and factories has increased rapidly, and environmental pollution due to shortage of disposal sites and illegal dumping is becoming more and more serious. In addition, there are major social problems such as soaring processing costs, setting up industrial waste treatment plants, and refusing to bring in industrial waste from other prefectures, mainly in urban areas. There are many restrictions on dumping waste. The present invention has been made in view of these actual conditions, and reuses silica sand fine powder (industrial waste) generated during the reproduction of foundry sand as a raw material, mixes with other materials, forms a molded body, and colored bricks, etc. To provide the product of.

[0005]

DISCLOSURE OF THE INVENTION The present inventor has to discard until now by using silica sand fine powder generated at the time of reclaiming foundry sand as an aggregate, mixing this with a material such as cement, mixing and molding. The invention has reached the point where the fine silica sand powder that could not be obtained can be reused. That is, the first invention of the present invention has a particle size of 2 to 30 μm.
m silica sand fine powder 70 to 80% by weight, coal powder 20 to 10% by weight, and other bentonite 5 to 7% by weight, balance cereals and iron oxide powder, and cement 40 to 60 in comparison with the aggregate. By weight, 5 to 20% by weight of a cement admixture and 25 to 60% by weight of water are mixed with the cement, and the aggregate / cement mixture is molded into a molded body of a predetermined size by a vibration press molding machine. Bentonite is prepared by combining alkali bentonite and alkaline earth bentonite in combination to utilize the respective characteristics of caking properties. In addition, flours are added to increase the fluidity of the mixture. Iron oxide is added in the sense of coloring (reddish red).

Next, the second invention of the present invention is, by weight ratio,
Bread 50-70% and silica sand fine powder 50 with particle size 2-30 μm
To 80% by weight of cement, and 3 to 4% by weight of cement admixture, 1 to 2% by weight of AE water-reducing agent and 20% of water relative to the cement.
-30% by weight is mixed, and the aggregate / cement mixture is molded into a molded product having a predetermined size by a vibration press molding machine.

Regarding the compounding material in the present invention, the bread which is dust collecting dust is free from lumps (granulation), is sufficiently dried, and is kept at about 20 ° C. during mixing.
The casting sand silica sand fine powder has a grain size of 2 to 30 μm and has a round grain shape. Then, like bread, it is sufficiently dried, and when it is blended, it is kept warm at around 20 ° C. The cement used is Portland cement, which has a weight loss of 1% or less when heated at 950 ± 50 ° C. The cement admixture contains CaCl ₂ to stabilize its components.
Is powdered, cement and CaCl
Use a mixture of ₂ . The AE water-reducing agent is used because it has the effect of raising microbubbles and fluidity and increasing the bending strength by 30 to 50%. The water used has a water quality of the level of water supply, has a pH range of 6 to 8, and contains salts and sugars of less than 3%.

An example of the physical properties of the casting sand silica sand fine powder used in the present invention will be described. The chemical composition (% by weight) is SiO ₂ 64.
40, Al ₂ O ₃ 10.98, Fe ₂ O ₃ 2.76, M
gO1.27, CaO0.97, pH 7.84,
Particle size 10 μm is 43.3%, specific surface area 19366 cm
^{It was 2} / cm ³ . This chemical component should also be called a representative of acid refractory clay bricks, and the chemical composition of chamotte bricks used in various heating furnaces and ladle bricks (from low quality to high quality ) Example of SiO ₂ 50-60%, Al ₂ O ₃ 30-45%,
Fe ₂ O ₃ about 2%, MgO 0.1-0.5%, CaO
There are some similarities to 0.3-2%.

[0009]

EXAMPLE AND FUNCTION FIG. 1 is a sketch drawing of a microphotograph (200 times) of the molded article of the present invention. FIG. 2 is a sketch drawing of a microphotograph (200 times) of a molded body of an aggregate / cement mixture which has not been crushed into aggregates generated after kneading with a mixer. FIG. 3 is a schematic vertical sectional view of the vibration press molding machine. The present invention will be described below. (Example 1) Silica sand fine powder 70% and coal powder 15 by weight ratio
%, Bentonite 6%, iron oxide 1.0%, and the balance flour, 50% by weight of cement with respect to the aggregate 100 is mixed and mixed for 30 seconds. After adding a small amount of water to the cement admixture (15% by weight relative to cement) and kneading,
The remaining water (the amount of water added is 50% by weight relative to cement) is added and diluted. Then, a mixture of aggregate and cement was added, and the mixture was kneaded with a high-speed mixer for 2 minutes. 1-2 mm in particle size
Since the aggregates having the diameter were formed, the aggregates were crushed with a mixer having an aggregate crushing function. This agglomerated state remains after the molding, and the agglomerated particles are bonded to each other, and cracks occur at the grain boundaries, which is not preferable. After the kneading was completed, the aggregate / cement mixture was finely pulverized and was in a tattered state. The mixture thus prepared by kneading the compounding material was molded at room temperature within 5 minutes after kneading using a vibration press molding machine (FIG. 3).

The molding method is as shown in FIG.
0 and its bottom lid 18 are filled and supplied with a predetermined amount of aggregate / cement mixture 19 made by kneading the compounding material, and the top lid 11 is put on the molding die to put them in contact with each other. Engage and place it on the molding table 17. First, the upper hydraulic cylinder 16 is operated to operate the upper frame 14 and the pusher 12 thereof.
And the like, and the pressing plate 12 is held in contact with the upper surface of the upper lid 11 so that the molding die is stably sandwiched and supported between the molding table 17 and the pressing plate 12. Then, the lower vibrator 9 on the side of the molding table 17 and the upper vibrator 13 on the side of the press plate 12 are operated at the same time, or by operating them in tandem.
While applying vibration force to the aggregate / cement mixture 19 in the molding die, pressurizing hydraulic cylinders 16 and 8 arranged in the upper and lower parts
Is applied to clamp the upper and lower surfaces of the top lid 11 and the bottom lid 18 and press both sides. Pressure press thrust is 20 ~ 35kg
f / cm ² .

The aggregate / cement mixture 19 in the mold is
The vibrating force due to the relative action of the vibrators 9 and 13 at the upper and lower portions, and the relative vertical pressure applied by the pressurizing air cylinders 8 and 16 at the upper and lower portions do not cause coarse and fine molding spots in the upper, lower, left, and right, and so on. And, it was uniformly press-molded, and a molded product having a uniform filling degree and tightness was obtained.
The compression force of the molded body was 25 kgf / cm ² , and the target was achieved. If the vibration pressurizing time is too short, harmful large air bubbles will remain in the molded product, and if it is too long, the effective minute air bubbles will be reduced. The mold temperature of the mold was 20 ° C. (up to 40 ° C. was the maximum). The molded body thus produced was wrapped with a wet cloth, and was subjected to wet curing for 4 days and then atmospheric curing for 28 days. In the wet curing, steam or mist may be sprayed instead of wrapping with a wet cloth. Since the material of the present invention is a kind of polymer cement, underwater curing or high temperature curing gives rather bad results. The atmospheric temperature during curing is 20
The target temperature was controlled at 20 ° C so that the temperature did not drop below ℃. A sketch of a microphotograph (200x) of the cross section of this compact is shown in Figure 1.
It was the street. This aggregate / cement mixture was in the state of fine particles 2 and was good. In this example, the aggregate was crushed, but a sketch of a microphotograph (200 times) of an aggregate-cement mixture compact which was not crushed was separately shown in FIG. The state remains after molding. The aggregates were large, and grain boundaries between the aggregates were generated, which was not desirable.

(Embodiment 2) An aggregate having a weight ratio of 50% bread and 50% foundry sand silica fine powder is added to the aggregate 100.
70% by weight of cement is blended with respect to 10% and mixed for 30 seconds. After adding a small amount of water to the cement admixture (3.0% by weight relative to the cement) and kneading, add the remaining water (the amount of water added is 25 to 30% by weight relative to the cement), and also add the AE water reducing agent. To dilute. Then, a mixture of aggregate and cement was added, and the mixture was kneaded with a high-speed mixer for 2 minutes. Then, Example 1
In the same manner as in (1), the aggregate was crushed and molded. Although a microphotograph of this cross section is not shown, it was almost the same as in FIG.
The molded articles of Examples 1 and 2 were
It goes without saying that you can carry out curing. These molded products can be used for footpaths for sidewalks, colored bricks, flower pots and the like.

[0013]

As described above, according to the present invention, it is possible to reuse the dust collecting dust and the molding sand silica sand fine powder at the time of reclaiming the molding sand, which had to be thrown away as industrial waste, as a raw material, and the disposal site. And the problem of environmental destruction are solved, and the disposal cost can be saved.

[Brief description of drawings]

FIG. 1 is a sketch drawing of a microphotograph of a molded product of the present invention.

FIG. 2 is a sketch drawing of a microphotograph of a molded body of the mixture without crushing aggregates.

FIG. 3 is a schematic vertical sectional view of a conventional vibration press molding machine.

[Explanation of symbols]

 1 Molded body 2 Fine granules of aggregate / cement mixture 3 Aggregate of aggregate / cement mixture 4 Remaining aggregated boundary after molding 7 Press machine stand 8, 16 Pressurized hydraulic cylinder 9 Lower vibrator 10 Forming frame 11 Upper lid 12 Pusher 13 Upper vibrator 14 Upper girder 15 Fixed girder 17 Forming stand 18 Bottom lid 19 Aggregate / cement mixture 20 Vibration press forming machine

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication C04B 14:10 Z 2102-4G 14:30 2102-4G 16:02) 2102-4G (72) Invention Akira Nakamura 13 Kinugaoka, Moka City, Tochigi Prefecture Inside the Moka Plant, Hitachi Metals Co., Ltd. (72) Inventor Kei Mori 1500-38 Kuwabe, Kuwana City, Mie Prefecture

Claims (6)

[Claims] 1. An aggregate and a cement 40 to 1 in the ratio of the aggregate.
Cement admixture 5 to 100% by weight in comparison with the cement.
A molded product comprising a combination of 20% by weight and 40 to 50% by weight of water. 2. The aggregate is composed of 70 to 80% by weight of fine silica sand powder having a particle size of 2 to 30 μm, 20 to 10% by weight of coal powder, 5 to 7% by weight of other bentonite, the balance flour and iron oxide. The molded product according to claim 1. 3. An aggregate and cement 60 to 60 in comparison with the aggregate.
Cement admixture 3 to 80% by weight, in comparison with the cement
4 wt%, AE water reducing agent 1-2 wt% and water 25-30
A molded product, characterized in that it comprises a combined product with a weight percentage. 4. The bread is 50 to 70% by weight of the aggregate.
And a ratio of 50 to 30% of fine silica sand powder having a particle size of 2 to 30 μm. 5. The molded product according to claim 1, which is a stepping stone for sidewalks or a colored brick. 6. (a) a step of mixing an aggregate and cement; (b) a step of mixing a cement admixture and water, or a cement admixture, water and an AE water reducing agent, and (c) the above ( (A) and kneading the respective mixture obtained in the respective steps (b) with a mixer, followed by fine crushing of aggregates to obtain an aggregate / cement mixture, and (d) the above A method for producing a molded article, which comprises a combination of steps of molding an aggregate / cement mixture.