JPH0967158A - Production of brick by effectively utilizing sewage sludge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a high quality brick for a civil construction with a low cost capable of producing by a low pressure pressing while eliminating the need for a high pressure pressing and capable of producing by a low energy consumption while lowering a firing temp. by effectively utilizing a sewage sludge. SOLUTION: A low refractory viscosity mineral of 10-20wt.% and/or 0.1-3.0wt.% alkali metal oxide are added to and mixed with 100wt. ratio of a composition having a grain size construction of 30-70wt.% fine granules having 1-8mm grain size, 10-30wt.% particulate having 0.1-1mm grain size and 10-40wt.% fine powder having <=0.1mm powder size of a molten slag, and after kneading with water to impart plasticity thereto and subjecting the mixture to a press forming and drying, and the dried matter is Bired at <=1000 deg.C.

Description

Detailed Description of the Invention

[0001]

[Industrial application] With the progress of sewerage, the method of disposing sludge generated at sewage treatment plants has become a problem, and it is desired that sludge be effectively utilized. As a typical disposal method, there is a method of incinerating sludge to form ash, and further melting the ash to form slag. Although this method is expensive, the volume reduction rate for disposal is the largest, and the adoption of this method is increasing in urban areas. TECHNICAL FIELD The present invention relates to a method for effectively producing and using bricks for civil engineering and construction using a large amount of sludge slag and ash that are generated in the future as main raw materials.

[0002]

2. Description of the Related Art Among the methods of effectively utilizing incineration ash of sewage sludge and molten slag as a material for civil engineering and construction, a method of making a brick for a pavement or a brick for a house is performed. In the case of bricks made from incinerated ash as a raw material, the ash is a dust collected ash, which is very fine with an average particle size of 20 to 30 microns, and is a light material, so 500 kg / cm ^{3 to} 1000 kg / c
Increase the packing density by high-pressure molding of m ³ and the firing temperature is 100
A high temperature of 0 ° C to 1100 ° C was required. In this method, the equipment of the molding press becomes expensive, and the energy consumption for firing must be large. The same applies to the case of making a baked brick in the case of molten slag. The added value is small as it is effectively used as concrete, interlocking aggregate material, ballast, and backfill material. If cheaper, easier to use, and more versatile bricks for civil engineering and construction can be developed, the range of use can be expanded as a municipality, but the range of use of conventional bricks is narrow,
The current situation is that the cost of manufacturing is too high and it is in distress.

[0003]

PROBLEM TO BE SOLVED BY THE INVENTION A method for improving the performance and the low cost in the case of manufacturing a brick for civil engineering construction by effectively utilizing sewage sludge is provided. First, molten slag is used as an aggregate, and the aggregate is made to have a grain size to increase the packing density without the need for high-pressure molding to create a dense brick structure.
This is a method in which sufficient mechanical strength can be obtained at a temperature of 1000 ° C. or lower by using a clay mineral or an alkali metal oxide having a low refractory degree as a binder. This method does not require a high pressure press and allows production by a low pressure press. In addition, the firing temperature is kept low, and energy consumption is reduced, enabling production. Thus, the effective use of sewer sludge is to produce a high-quality civil engineering and construction brick at low cost.

[0004]

[Means for Solving the Problems] In order to obtain a sufficiently satisfactory packing density by pressure molding with a low-pressure press, the molten slag of sewage sludge is finely divided into particles of 8 mm to 1 mm, 1 mm to
This can be achieved by selecting the particle size distribution of these particles in the case of classifying into the particle constitution of fine particles of 0.1 mm and fine particles of 0.1 mm or less. That is, first, as many fine particles as possible are filled in the gaps filled with the fine particles, and further, by creating a structure in which the fine powders fill the gaps between these fine particles, the molded body of the constituents has a low pressure. By this, a compact having a high density can be obtained. The present invention has an optimum particle size composition of 30 to 70% by weight of fine particles and 10 to 100% of fine particles.
It is claimed that the desired packing density can be obtained by setting 30% by weight and 10 to 40% by weight of fine powder. If the amount of fine particles is less than 30% by weight, the proportion of fine particles and fine powder increases, and dense packing cannot be performed. If the amount of fine particles is more than 70% by weight, the structure becomes coarse and the strength becomes poor. If the amount of fine powder is less than 10% by weight, the gap between fine particles is not sufficiently filled, and if it is more than 30% by weight, the structure becomes coarse and the strength is poor. If the amount of fine powder is less than 10% by weight, the structure becomes rough and the strength cannot be obtained, and if it is more than 40% by weight, dense packing cannot be performed. By adjusting the molten slag particle size of sewage sludge as described above, press molding at low pressure is facilitated. Clay minerals are used to impart shape retention and plasticity to the formed clay. This clay mineral is SK07-SK01
1 to 20 with low fire resistance of about 900 to 970 ° C
Select% by weight. If it is less than 1% by weight, sufficient plasticity cannot be obtained at the time of molding, and if it is used in excess of 20% by weight, the plasticity is sufficiently satisfactory, but it is not necessary to use it any more, and if it is used more than this, the usage rate of slag is increased. It deviates from the purpose of raising it and causes cost increase. Sinterable at a low temperature of 1000 ° C. or less. Further, in order to lower the sintering temperature, 0.1 to 3% of alkali metal oxide is added.
An effect can be obtained by using 0% by weight. The alkali metal oxide easily reacts with the molten slag of sludge such as SiO ₂ and Al ₂ O ₃ to form a low melt, and enables low temperature sintering.

The molten slag of sewage sludge is adjusted to a predetermined particle size and blended, and the mixture is put into a pan-type mixer, and silicic acid silicate or the like is used as a binder alkali metal oxide, or bentonite or the like is used as a low refractory clay mineral together with a predetermined water content. Knead with stirring. In order to obtain a sufficiently satisfactory plasticity, it is important to knead under pressure. The kneaded material in which the molten slag and the binder can be uniformly kneaded and which has an appropriate degree of plasticity is charged into a predetermined mold and pressure-molded by a press. With regard to the press, the impact type molding of the friction press can be minutely molded even with an apparatus having a relatively small capacity.

The press-molded brick is dried and sintered in a firing process. A tunnel type continuous firing furnace is efficient. Heavy oil, gas, or electricity is used as the fuel, but since a heavy oil furnace generally has a low energy cost, it is suitable for producing this kind of recycled brick.

[0007]

[Example] Fine particles of molten slag of sewage sludge 8 mm to 1 mm
50% by weight, 20% by weight of fine particles of 1 mm to 0.1 mm and 25% by weight of fine powder of 0.1 mm or less, and 5% by weight of bentonite and 2% by weight of water glass No. 3, with a water content of 5%. Add 50% by weight and knead with a wet pan mixer, and with a 50t friction press, length 230m
A brick with m, width 115 mm, and thickness 60 mm was formed. After molding, it is dried at 110 ° C. for 24 hours, heated up to 950 ° C. at a rising temperature of 100 ° C./hr, kept at 950 ° C. for 3 hours, and cooled to room temperature at 80 ° C./hr. This brick has a bulk specific gravity of 2.10 g / cm ³ , a compressive strength of 650 kg / cm ² ,
It had a bending strength of 118 g / cm ² and was used as a laying brick for pavement. The molten slag of the sewage sludge itself contains a large amount of iron, so in the method of this example,
It was colored brown and could provide a calm landscape as a pavement. In addition, the brick surface can be coated with glaze for coloring, making it possible to create ceramic paving with various hues.

[0008]

【The invention's effect】

1. By selecting the optimum particle size composition and optimum binder for the molten slag of sewage sludge, it was possible to provide a brick for civil engineering and construction that can be manufactured by a simpler method. 2. Since it is a brick fired at a high temperature of up to 1000 ° C, its life is permanent, and by selecting colorful colors and applying glaze, it has great uses for pavements and buildings. 3. It is possible to construct a system as a certain income source because the cost of the national and local governments is saved as the effective use of general waste, and it is used for the production of effective materials.

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Claims (1)

[Claims] 1. Fine particles of molten slag of sewage sludge 8 mm to 1
mm to 30 to 70% by weight and 1 mm to 0.1 mm of fine particles
0 to 30% by weight and 10 to 40% by weight of fine powder of 0.1 or less
1 to 20% by weight of a low refractory clay mineral and / or 0.1 to 3.0% by weight of an alkali metal oxide are added to 100% by weight of a composition having a particle size constitution of 100% by weight, and mixed and kneaded with water to obtain plasticity. After press forming and drying, 1000
A method for manufacturing a brick, which is a brick for civil engineering and construction, which is fired at a temperature of ℃ or less, and which effectively utilizes sewage sludge.