JPH06128016A - Ceramic sinter and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] (Revised) [Purpose] Contribute to the prevention of environmental damage by reusing industrial waste municipal waste and sewer sludge as raw materials.
The purpose is to efficiently manufacture low-cost, high-quality porcelain sinters and establish a new breakthrough in ceramic materials in order to establish itself as an industry. [Structure] Municipal waste and sewer sludge are melted at high temperature and quenched in water to form glassy Al ₂ O ₃ , CaO / SiO ₂
And a mixture of a plastic raw material or a plastic raw material and a non-plastic raw material Mix the ceramic raw materials with the appropriate weight ratio,
They are baked and sintered at a temperature of 1000 [° C.] or more and 1300 [° C.] or less. Further, an alkali metal salt aqueous solution is mixed with them as a molding aid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention incinerates or melts municipal waste and sewer sludge among industrial wastes, which have been receiving the most attention in recent years for environmental destruction, to reduce their volume and to render them harmless. The present invention relates to a ceramic sintered body such as a construction material and other general ceramics formed by using the generated material, and a manufacturing method thereof.

[0002]

2. Description of the Related Art As a prior art relating to a ceramic sinter, there is one already invented by the inventors. It has a structure in which a crystallized glass particle group mainly composed of a natural or artificial raw material containing glass is bonded with an inorganic porous binder phase and is widely used as an industrial product. Also,
Ceramic sinter using blast furnace slag is also widely used. When the blast furnace slag is heated to 800 [° C.] to 950 [° C.], it is heated to gerenite (3CaO, Al ₂ O ₃ , 2Si).
The crystal of O ₂ ) is projected and is 80 to 1 during crystallization.
An exothermic reaction of about 00 [Cal / gr] occurs, which has the advantage that the firing time of the composition can be shortened and the fuel cost can be greatly reduced, and the volume is expanded by crystallization, and the firing shrinkage as a whole is reduced. As a result, it is widely used as a ceramic sinter, as described above.

[0003]

The object of the present invention: Problems to be solved: The ceramic sinter using natural or artificial raw material containing glass is of course effective as a sinter. Further, as described above, of course, the one using a blast furnace slag is also effective. However, if industrial waste such as municipal waste or sewer sludge can be used as the raw material for the ceramic sinter, the cost is far greater than that of the relatively expensive raw material such as the blast furnace slag. In addition to being able to achieve downtime, there is an advantage that environmental damage due to leaving industrial waste can be prevented.

However, the refuse incineration ash produced by incinerating a mixture of various materials such as municipal waste at a relatively low temperature of about 800 [° C.] to 1000 [° C.] is used as a raw material for a ceramic sinter. When using it, there are the following problems. That is, although various materials are mixed in the municipal waste, even if the metal components are separated and incinerated, the chemical components are extremely unstable, and the contraction rate of the sintered body fluctuates widely. However, it is difficult to industrially mass-produce it as a ceramics sintered body. On the other hand, in the case of waste incineration ash using sewage sludge, the composition is relatively more stable than in the case of municipal waste, but in the case of waste incineration ash of sewer sludge mixed with soil and sand during rainfall, SiO ₂ , Al ₂ The quality is still unstable because O ₃ , phosphoric acid components, etc. fluctuate about ± 5 [%] and are mixed. Also, since the waste incineration ash of sewer sludge is fine ash, it is difficult to deaerate the powder in the mold during powder processing and molding. There is a problem that a molded product cannot be obtained unless a mold is used and pressure molding is performed for several hours. Further, when this molded product is fired, if it exceeds 1000 [° C.], a very large sintering shrinkage of 15 [%] to 20 [%] occurs, and even a slight variation in the composition greatly affects the product size and stabilizes. It was difficult to mass-produce products of the specified quality. For this reason, the products using these refuse incineration ash have been applied only to relatively low-quality brick-shaped products. In addition, in order to solve the problems of the waste incineration ash, powders of feldspar, porcelain stone, and crushed ceramic porcelain, which are general raw materials for ceramics, are used as a main raw material, and the waste incineration ash is mixed with the porcelain to sinter. Some of them produce a body, but even in this case, if the mixing ratio of the refuse incineration ash exceeds 30 [%], the quality becomes unstable and the product cannot be commercialized.

The present invention was devised in view of the above circumstances, and does not use natural or artificial raw materials or expensive blast furnace water slag, and produces municipal waste of industrial waste which has become a problem recently. The purpose of the present invention is to provide a ceramic sinter that has high productivity, low cost and stable quality, and a method for producing the sewage sludge as a raw material, utilizing their characteristics and specifying the treatment method. .

[0006]

Constitution of the present invention: Means for solving the problems The present inventor has conducted a chemical analysis of the municipal solid waste and sewer sludge, which have recently been particularly problematic as industrial waste, which have been melted at high temperature into a sludge. As a result of conducting basic physical property research such as line diffraction and thermal analysis, we were convinced that it could be used to manufacture a ceramic sinter. That is, the amorphous coarse slag that has been melted at a high temperature of 1500 [° C.] or higher and vitrified, and then discharged from the bottom of the furnace and rapidly cooled in a water tank contains the impurities that have been mixed with the municipal waste. The stable metal material is melted and separated as a metal layer. Therefore, the content of the metal component is stable in the range of 2.0 to 3.5 [%]. Further, the work efficiency of slag formation is improved by melting, and the main components such as CaO and Al ₂ O ₃ SiO ₂ are corrected and managed. Therefore, the variation in chemical components is smaller than that of the conventional refuse incinerated ash incinerated at a low temperature. It was also found that the slag produced by the treatment process described above has many advantages over the blast furnace slag. Table 1 shows the chemical composition of sludge molten slag and blast furnace slag made from municipal waste.

[0007]

As shown in Table 1, the sludge molten water slag has about twice as much Al ₂ O ₃ content and CaO about 1/2 as compared to the blast furnace slag. In addition, sludge molten water slag is K ₂ O + Na ₂
It contains O in an amount of 3 to 4 [%], and Fl ₂ O ₃ is higher than slag of blast furnace. Furthermore, when the sludge molten slag and the blast furnace slag were heated and the properties of crystallization were examined, it was found that the blast furnace slag was 850 [° C] to 9
The sludge melt water slag has an exothermic peak between 00 [° C.] and 950 [° C.] to 950 [° C.], which is higher by about 50 [° C.]. In addition, when these crystals are examined by X-ray diffraction, anorthite (CaO, Al ₂ O ₃ , 2
SiO ₂₎ Deli, it was found that the same as the crystal minerals constituting ordinary for ceramic. In the case of general calcareous porcelain, SiO ₂ -Al ₂ O ₃ such as porcelain stone and clay is used.
Limestone is added to the raw materials of the system to add SiO ₂ —Al ₂ O ₃ , Ca
Although an O-based composition is produced and the chemical reaction in the firing process takes a long time to form the crystalline phase of anorthite, the slag can easily form the crystalline phase of anorthite in an extremely short time. I understand.

The present invention was devised on the basis of the above-mentioned various analyzes, and was researched and developed based on the fact that a ceramic sinter could be manufactured from municipal waste and sewer sludge as raw materials, and as a specific technique. It is a compilation.

According to the first and second aspects, municipal waste and sewer sludge are melted at a high temperature and rapidly cooled in water to form glass, in which Al ₂ O ₃ is contained in an amount of 15% or more and 30% or less. A sludge molten water slag that contains CaO / SiO _{2 and} has a composition of 0.8 or less is used. Al ₂ O ₃ and CaO / S
The range in which iO ₂ is regulated within the above range is a range in which the main crystal phase protruding during firing is anorthite, which is experimentally determined. The content of Al ₂ O ₃ is preferably about 20 [%] to 25 [%],
If it exceeds [%], the temperature at which crystallization starts is high, and problems occur while crystallization takes time. On the other hand, it is the sludge that the sludge molten water slag is set to 10% by weight or more and 95% by weight or less, and the ceramic raw material made of a plastic material or a non-plastic material is set to 90% by weight or less and 5% by weight or more. If the weight [%] of the molten slag is 10 weight% or less, the object of the present invention is not satisfied, and if it is 95 weight [%] or more, the expansion coefficient during firing is large and the quality of the ceramic sinter is deteriorated. Is. Moreover, the temperature during firing and sintering is 1000 [° C.] or more and 1300
[° C] or less was determined experimentally by controlling the volumetric expansion of the sludge molten slag during firing to below a certain value and by referring to the theoretical fire resistance of anorthite (1550 [° C]). is there.

In the third aspect, when a ceramic sinter is produced by the powder pressure molding method, an aqueous solution of an alkali metal salt of sodium silicate, potassium silicate or the like is used as a molding aid in a solid content of 1% to 3%. %] And allowed to cure for several hours (about 3 hours) because the surface of the water clumps reacts with the aqueous metal salt solution to produce a sticky or adhesive paste, and the baking process This is because the bonding between particles is promoted in the low temperature region of 1, and a sintered body having high strength is formed. Also,
In the present invention, a plastic raw material of 5% to 10% in terms of solid content is used as a molding aid, and a paste-like material is produced in the same manner as in the case of the alkali metal salt aqueous solution. This is to improve the strength.

[0012] In claim 5, sludge molten slag consisting of municipal refuse or sewer sludge and refuse incineration ash obtained by firing urban refuse or sewer sludge at a relatively low temperature of 800 [° C] to 1000 [° C]. It is different from claim 1 in that a mixture of these is used. Sludge melt water slag is 1100
Crystallization proceeds at [° C.] or higher, and in particular, the metallic iron component enclosed in the glass phase as a chemical component undergoes an oxidation reaction to cause volume expansion. According to the experiment, it was confirmed that a volume expansion of about 1.3 times occurred at 1180 [° C]. On the other hand, the fine powder dust incinerated ash begins to soften above 1100 ° C,
Vitrification occurs rapidly at 1170 [° C.] to 1190 [° C.], linear shrinkage of 15 [%] to 20 [%] occurs, and the volume changes to 1 / 1.5. Therefore, it is an object of the present invention to combine the two by utilizing the contradictory characteristics generated during firing to cancel the volume change and to stabilize the volume. Furthermore, the crystals of anorthite that are released from the sludge sludge slag theoretically have a fire resistance of 1550 [℃], and the reaction during the firing process is due to the increase of the glass phase of the refuse incineration ash and the crystallization from the sludge slag slag. Since it occurs in the same temperature range, the above-mentioned volume change is offset and softening deformation is prevented. This makes it possible to obtain a sintered body with a high shape and dimensional accuracy in a very short time. Further, the contents of claims 5 to 9 are the same as those described for the sludge molten water slag, and the description thereof will be omitted.

[0013]

EXAMPLES Examples of the present invention will be described below. In the examples described below, in order to further clarify the characteristics of the sludge molten slag and the refuse incineration ash, an experiment using a ceramic raw material and a sample in which these are mixed is not described because it is a normal experiment. Kaolin, plastic clay (Frogome clay, Kibushi clay), sericite porcelain stone, wax stone, bentonite, etc. are used as the plastic material of the ceramic material, and silica stone, chamotte, feldspar are used as the non-plastic material. , Limestone, magnesite, dolomite, wollastonite, talc, bone ash, etc. are used.

The sludge melt water slag used in the examples is 1 [m
m] to 0.5 [mm] particle size of 30 [%], 0.
50 with a grain size of 5 [mm] to 0.15 [mm]
[%], 0.15 [mm] or less particle size 20 [%]
Use a mixture. Moreover, as the refuse incineration ash of the sewer sludge, one burned at 800 [° C.] to 900 [° C.] and having a particle size of 0.15 [mm] or less was adopted.
As the sample, No. 3 having the mixing ratio shown in Table 2 below was used. 1 to No. Molding pressure of 200 kg / cm.
² , 300 [mm] x 300 [mm] x 20 [mm] floor tiles are molded, dried at a temperature of 120 [° C] to 150 [° C] for 1 to 2 hours, and then at room temperature using a roller hearth kiln. To 1000 [℃] for 30 minutes, 1000
A sintered body was manufactured by heating and firing between [° C.] and 1180 [° C.] for 30 minutes, and naturally cooling to room temperature in about 110 minutes.

[0015]

As a result, a ceramic sinter having the characteristics shown in Table 3 was obtained.

[0017]

The above ceramic sinter is completed in a firing cycle that is about twice as fast as the firing conditions for ordinary ceramic products, and the fired product is free from cracks and deformation.
The shape and dimensional accuracy were also extremely high. Also, Table 3
As shown in Fig. 4, the sludge melt water slag with a large [%] has a high expansion rate of 3 [%] at the time of firing, but when combined with waste incineration ash, the firing expansion rate or shrinkage rate is ± 0 [%]. It can be controlled. In addition, the compressive strength is about 2.5 times higher than that of concrete products.

[0019]

[Effect of the present invention]

1) Conventional sinters are made by pulverizing ceramic raw materials such as porcelain stone, feldspar, clay, limestone, etc., and mixing them. During the firing process, release of crystal water and decomposition and decomposition products of porcelain stone, feldspar and clay The present invention is to form a crystalline mineral that finally becomes the structure of the product by the complicated mutual chemical reaction of 1., which requires a long time for firing and has an extremely difficult element to control firing due to the unstable volume. According to the method, the target crystal mineral is rapidly extracted from the vitrified raw material in the process of extremely high productivity, and the self-heating reaction due to crystallization accelerates the calcination and the volume does not change. It is a ceramic product,
It is a highly productive manufacturing method that can produce extremely stable products. 2) Industrial waste such as municipal waste and sewer sludge can be recycled as a high-value-added sinter, which can prevent environmental damage and effectively use resources. 3) The ceramic sinter according to the present invention can be industrially manufactured and can be produced at low cost because the raw material is inexpensive. 4) Since the ceramic sinter of the present invention has high shape and dimensional accuracy and is formed with high quality, it is widely used as a landscape material or a construction material, and will open a breakthrough for new ceramic materials in the future. 5) The firing speed is faster than that of the conventional sintered body, and the productivity can be improved.

Claims (8)

[Claims] 1. Al ₂ O ₃ in a glassy material formed by melting municipal waste or sewer sludge at high temperature and quenching in water.
Containing 15% or more and 30% or less, and CaO
1 / Sludge melt water slag with a composition of SiO ₂ 0.8 or less
90 wt% or less in terms of a fired product of a composition (hereinafter referred to as a ceramic raw material) in which 0 wt% or more and 95 wt% or less and a plastic raw material or a plastic raw material and a non-plastic raw material are appropriately mixed 5 A ceramic sinter, characterized by being mixed, fired, and sintered with a weight [%] or more. 2. The sludge molten water slag is used in an amount of 10% by weight or more and 9 or more.
5% by weight or less and 90% by weight or less and 5% by weight or more of the above-mentioned ceramic raw material in terms of a fired product are mixed, hydroformed so as to be kneadable and dried, and then 1000 [° C] or more 13
A method for producing a ceramic sinter, which comprises producing a sinter by firing and sintering at a temperature of 00 [° C.] or less. 3. A method for producing a ceramic sinter by a powder pressure molding method, wherein the sludge molten water slag is 10 wt% or more and 95 wt% or less, and the porcelain raw material is converted into a fired product. A mixture of 90% [%] or less and 5% [%] or more is mixed with a molding aid consisting of an aqueous solution of an alkali metal salt of sodium silicate, potassium silicate, etc.
[%] To 3 [%] is added and molded, then cured for 3 hours or more, dried, and then 1000 [° C] or more and 1300 [° C]
A method for producing a ceramic sinter, which comprises firing and sintering at the following temperature to produce a sinter. 4. A plastic raw material of 5% to 10% in terms of solid matter is used as a molding aid instead of the molding aid composed of an aqueous solution of an alkali metal salt such as sodium silicate or potassium silicate. The method for producing a ceramic sinter according to claim 3. 5. The sludge molten water slag according to claim 1 is 3% by weight or more and 76% by weight or less, and municipal waste or sewer sludge is relatively low at 800 [° C.] to 1000 [° C.]. 7% by weight or more and 19% by weight or less of the refuse incineration ash that is fired at a temperature to form a fine powder, and 90% by weight or less and 5% by weight or more of the above ceramic raw material in terms of a fired product Ceramic sinter that is characterized by being mixed, fired and sintered. 6. The sludge molten water slag according to claim 1, which is 3 wt% or more and 76 wt% or less, and municipal waste or sewer sludge of 800 [° C.] to 1000 [° C.], respectively. 7% by weight or more and 19% by weight or less of refuse incineration ash that is fired at a low temperature to form a fine powder, and 90% by weight or less and 5% by weight or more of the above ceramic raw material in terms of a fired product The mixture is molded and then 1000 [° C] or more 1
A method for producing a ceramic sinter, which comprises firing and sintering at a temperature of 300 [° C.] or less to produce a sinter. 7. The sludge molten water slag according to claim 1 having a content of 3% by weight or more and 76% by weight or less, and municipal waste or sewer sludge having a temperature of 800 [° C.] to 1000 [° C.], respectively. 7% by weight or more and 19% by weight or less of refuse incineration ash that is fired at a low temperature to form a fine powder, and 90% by weight or less and 5% by weight or more of the above ceramic raw material in terms of a fired product In addition to the above, a molding aid consisting of an aqueous solution of an alkali metal salt of sodium silicate, potassium silicate, etc. is added to the mixture of
[%] To 3 [%] is added and molded, then cured for 3 hours or more, dried, and then 1000 [° C] or more 1300
A method for producing a ceramic sinter, which comprises firing and sintering at a temperature of [° C] or less to produce a sinter. 8. A plastic raw material of 5% to 10% in terms of solid matter is used as a molding aid instead of the molding aid composed of an aqueous solution of an alkali metal salt such as sodium silicate or potassium silicate. The method for producing a ceramic sinter according to claim 7.