JP2006255609A - Method for manufacturing sintered product and sintered product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a sintered product which can use a large amount of soil generated at construction sites, industrial waste, general waste, or refuse stone in stone crushing plants, and which manufactures the sintered product from the waste as main raw materials with a high productivity, utilizing a nonoperating plant or an extisting plant as it is, eliminating any troublesome process. <P>SOLUTION: At least one kind out of the soil generated at construction sites, the industrial waste, the general waste and the refuse stone on the stone crushing plants is selected as a main raw material. After the raw material is adjusted to a desired chemical composition by adding and mixing a component adjusting agent and/or a sintering auxiliary agent as required, the adjusted raw material is charged from the bottom of a rotary kiln in the state of powder and/or granular of a size of 5 mm or less. A raw material with a melting point lower than that of the raw material charged from the bottom of the rotary kiln is blown into in the state of the powder from the top of the rotary kiln. Both the raw materials are sintered while being mixed in the rotary kiln. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method for producing a sintered product and a sintered product, and in particular, to produce a high-strength and low water-absorbing sintered product using waste such as construction generated soil and industrial waste as a main raw material. The present invention relates to a method and a sintered product.

The amount of soil and residual soil generated from construction sites and construction sites, industrial waste and general waste reaches millions of tons per year, most of which is landfilled without being effectively utilized. However, in recent years, the landfill disposal site on the receiving side has become increasingly depleted, and all the generated waste cannot be received.
In addition, disposal costs necessary for disposing of these materials have been increasing year by year, and this situation has caused social problems such as illegal dumping of these wastes.

The background of the depletion of such disposal sites, and furthermore, industrial waste is mainly composed of inorganic minerals, so cement and water are added to industrial waste etc. A method of reusing as a backfill material or the like has been proposed (for example, Patent Document 1).
However, the reuse method as disclosed in Patent Document 1 has a low utility value for a high processing cost for performing the processing, and its practical use is not progressing.

In addition, a method has been proposed in which various wastes are used as a main raw material, cement is added to the raw material, and the mixture is molded and solidified to produce an aggregate granule (for example, Patent Document 2).
According to the present invention, there is a feature that various wastes can be processed, but on the other hand, since it is a solidification method using cement, there is a problem that a manufacturing process such as a kneader and a molding machine becomes complicated and processing costs increase. .

On the other hand, the production capacity of cement to meet the recent demand for cement, that is, the existing production facilities are excessive, so it is unavoidable to take measures such as turning off rotary kilns. For example, a method of utilizing as a part of a system for producing a cement raw material by fermenting municipal waste and producing cement raw materials has been proposed (for example, Patent Document 3).
However, the utilization method of such an idle facility is enormous in the cost of remodeling the facility, and a new utilization method of an idle facility, etc. that directly utilizes facilities such as a rotary kiln is desired.

Japanese Patent Laid-Open No. 2001-19524 JP 2002-179445 A JP 2001-191060 A

The present invention has been made in view of the problems and demands of the background art described above, and its purpose is to use a large amount of construction generated soil, industrial waste, general waste, or crushed stone from a quarry. In making a sintered product using these wastes as a main raw material, the idle equipment or the existing equipment is used as it is, a complicated process is omitted, and a sintered product is produced with high productivity, and The purpose is to provide a high-quality sintered product made mainly from waste.

As a result of intensive studies to solve the above-described problems, the present inventors have appropriately combined wastes, or added and mixed a component adjusting agent and / or a sintering aid to the wastes. After adjusting to a raw material of a predetermined chemical composition, the adjusted raw material is powdered or shaped into a predetermined particle or less and charged from the kiln bottom of the rotary kiln, and the melting point temperature is higher than the raw material charged from the kiln bottom. By blowing low raw materials from the kiln of the rotary kiln in powder form and mixing and firing both raw materials, it is possible to efficiently produce sintered products with moderate size, high density, low water absorption, and high strength. The headline and the present invention were completed.

That is, the present invention uses at least one selected from construction-generated soil, industrial waste, general waste, and crushed stone from a quarry as a main raw material. After adding and mixing the binder and adjusting to a predetermined chemical composition, the adjusted raw material is charged from the kiln bottom of the rotary kiln in a powder and / or granular state of 5 mm or less, and from the raw material charged from the kiln bottom In addition, a raw material having a low melting point temperature was blown in powder form from before the kiln of the rotary kiln, and a method for producing a sintered product was fired while mixing both raw materials with the rotary kiln.

Here, the melting point temperature of the raw material blown from before the rotary kiln kiln is preferably 30 to 100 ° C. lower than the melting point temperature of the raw material charged from the rotary kiln bottom,
The amount of raw material blown from before the kiln of the rotary kiln is preferably 5 to 15% by weight of the amount of raw material charged from the bottom of the rotary kiln. In addition, the raw material blown from before the kiln of the rotary kiln is mainly made of at least one selected from construction generated soil, industrial waste, general waste, and crushed stone from the quarry, as is the case with the raw material introduced from the bottom of the kiln. The main raw material is preferably adjusted to a predetermined chemical composition and melting point temperature by adding and mixing a component adjusting agent and / or a sintering aid as required.

In addition, the present invention is a sintered product mainly composed of one or more selected from construction generated soil, industrial waste, general waste, and crushed stone from a quarry, and has an absolutely dry density of 1.0 to 1.0. A sintered product having a water absorption of 2.5 g / cm ³ , a 24-hour water absorption and a vacuum water absorption of 0.1% or more and 15% or less, and a crushing load of 0.5 kN or more was obtained.

Here, the sintering was, the CaO 5 to 30 wt%, a SiO ₂ 30 to 70 wt%, Al
The ₂ O ₃ preferably contains 10 to 40 wt%. Moreover, it is preferable that the said sintered compact contains 15-50 weight% of at least anorthite as a mineral seed | species.

According to the above-described method for producing a sintered product according to the present invention, the low melting point raw material blown from before the kiln of the rotary kiln is melted, and acts as a binder for bonding the raw materials, covering the surface of the raw material or granulated product. In addition to filling the gap between the particles, helping the granulation of the raw material charged from the kiln bottom of the rotary kiln, and contributing to the high strength and low water absorption of the granulated product, Without granulating or shaping the raw materials, such as waste, into a predetermined size in advance, the firing temperature of the rotary kiln can be lowered, the adhesion of the raw materials into the kiln can be reduced, and high strength can be achieved efficiently. In addition, a sintered product with low water absorption can be produced.

Moreover, according to the sintered product according to the present invention described above, since it has high strength and low water absorption, it is suitably used as an aggregate for concrete, a roadbed material, a backfill material, a substitute for clay as a cement raw material, and the like. In addition, since wastes such as construction generated soil and industrial waste are used as the main raw material, waste can be used effectively and idle rotary kilns can be used as they are. Is an invention that exhibits excellent effects.

Hereinafter, the manufacturing method of the sintered product and the embodiment of the sintered product according to the present invention will be described in detail.

The construction generated soil used in the present invention refers to soil, mud, residual soil, waste soil, etc. generated during excavation at construction sites and construction sites, dredging work of dams, etc., and these improve handling and transportability. Therefore, modified soil to which a modifying material such as slaked lime is added is also included. In addition, as industrial waste used in the present invention, for example, raw consludge, various sludges (for example, purified water sludge, construction sludge,
Steelmaking sludge), construction waste, concrete waste, boring waste, various incineration ash (for example, coal ash, incineration fly ash, molten fly ash, etc.), foundry sand, rock wool, waste glass, blast furnace secondary ash, etc. It is done. Furthermore, examples of the general waste used in the present invention include sewage sludge, sewage sludge dry powder, sewage sludge incineration ash, municipal waste incineration ash, municipal waste incineration fly ash, and shellfish. Further, the crushed stone used in the present invention refers to an unsieved product or the like that is extracted in a sieving step by mining road aggregate, concrete aggregate, and the like.

In the present invention, one or more kinds selected from the above-mentioned construction generated soil, industrial waste, general waste and crushed stone from a quarry are used as a main raw material.
Hereinafter, one or more selected from construction generated soil, general waste, industrial waste, and crushed stone from a quarry may be simply referred to as waste or the like.

The wastes and the like used in the present invention are recommended to have an average particle size of 1 to 300 μm because of good sinterability, and particularly preferably those having an average particle size of 1 to 50 μm. When larger than 300 micrometers, what adjusted the particle size by grinding | pulverization etc. can be used. At this time, the pulverization may be a continuous type or a batch type, but a continuous type is recommended from the viewpoint of economy. When the average particle diameter is less than 1 μm, the sinterability of the raw material is improved, but the cost for pulverization is undesirably increased. In addition, you may use a waste etc. by drying with dryers, such as a rotary dryer, before and after grinding | pulverization as needed.

Some of the above-mentioned wastes and the like contain an organic matter of several percent to several tens of percent as a loss on ignition, but in the present invention, as described later, the raw material form is a powder or a particle form having a predetermined particle size or less. Since the combustion reaction proceeds easily in the firing process and the organic matter is completely combusted, it is not necessary to provide any restrictions on the organic matter content in the waste used.

In the present invention, the above-mentioned waste or the like is used as a main raw material, and a component adjusting agent and / or a sintering aid is added to the main raw material as necessary to obtain a raw material having a predetermined chemical composition. However, from the viewpoint of mass use of waste, etc., it is preferable not to use component modifiers and / or sintering aids as much as possible. For this reason, the above-mentioned construction generated soil, general waste, industrial waste, quarry It is preferable to combine the waste stones as appropriate so that the chemical composition of the waste material itself as the main raw material is the chemical composition of the target raw material, or at least close to the chemical composition of the target raw material.

Chemical composition of the raw material as a target is, CaO 5 to 30 wt%, SiO ₂ 30 to 70 wt%
It is preferable to adjust so that 10 to 40% by weight of Al ₂ O ₃ is contained.
This is not preferable because when CaO is less than 5% by weight, the firing temperature is remarkably increased, which is impractical and difficult to control the quality of the sintered product, such as poor fireability. On the contrary, if CaO is contained in an amount of more than 30% by weight, the firing temperature rises,
This is not preferable because the easy baking property is deteriorated. If the SiO ₂ content is less than 30% by weight,
It is not preferable because the firing temperature rises and the ease of firing becomes poor, and if it exceeds 70% by weight, the firing temperature rises remarkably and is not practical and not preferred. When Al ₂ O ₃ is less than 10 wt%, such as outbreak of the liquid phase is not preferable for stable operation becomes difficult, _Al 2 O
_{If 3} is present in an amount exceeding 40% by weight, the firing temperature is remarkably increased, which is not preferable because it is not practical.

Examples of the component modifier include, for example, silica powder, clay, kaolin, and bentonite as the SiO ₂ source. Examples of the Al ₂ O ₃ source include alumina powder and aluminum ash. Furthermore, as a CaO source, limestone powder, slaked lime, quicklime, cement,
Examples include gypsum.

About the particle size of the said component regulator, from the reactivity with a waste etc., it is 1-300 in an average particle diameter.
It is preferable that it is micrometer, and it is especially preferable that it is 1-50 micrometers in average particle diameter. 3
When it is larger than 00 μm, a particle whose particle size is adjusted by pulverization or classification can be used. If the particle size of the component modifier is smaller than 1 μm, it is not preferable because the cost for pulverization and the like increases, and if it exceeds 300 μm, the reactivity with waste and the like is remarkably deteriorated, and the effect as a component modifier is obtained. It is not preferable because it is not possible.

On the other hand, the sintering aid is, as the name suggests, added to promote the sintering reaction, and has already been added to the waste material as a main raw material, or a mixture of waste material and the above-mentioned component modifier. If sinterability is provided, it is not necessary to add in particular. However, if these raw material components cannot ensure sufficient sinterability, a sintering aid is added.

There are various types of sintering aids. For example, among the above-described component modifiers, clay, kaolin, bentonite, various Al ₂ O ₃ sources and cements have an effect of promoting sintering. Have both. Also. MgO also has an effect of promoting sintering. Mg (OH) ₂ , MgCO ₃ , CaCO ₃ .MgCO ₃ (dolomite), MgO.Al ₂ O ₃ (containing this component as well as MgO are included. Spinel), 2MgO.SiO ₂ (forsterite) and the like are also suitable. Also, ferronickel slag, which is a by-product of steel, can be said to be a more suitable material from the viewpoint of not only high content of MgO but also effective utilization thereof.

Alkali metal oxides and composite oxides such as K and Na, such as sodium carbonate and potassium carbonate, are also known to show the effect of promoting the sintering reaction. Also suitable are feldspars such as feldspar, glass, mica and meteorite. Waste glass and red mud are also suitable materials from the viewpoint of their effective use. The oxide or composite oxide containing Fe, for example, since the like Fe ₂ O ₃ powder and iron again has both the effect of promoting sintering reaction, may be added, if these demands.

The particle size of the sintering aid to be added is preferably 1 to 300 [mu] m in average particle diameter, and more preferably 1 to 50 [mu] m in average particle diameter from the viewpoint of reactivity with waste and the like. 3
When the particle size is greater than 00 μm, the particle size adjusted by pulverization or the like can be used.
If the particle size of the sintering aid is smaller than 1 μm, it is not preferable because the cost for pulverization and the like increases, and if it exceeds 300 μm, the reactivity with waste and the like deteriorates, and the effect as a sintering glaze is obtained. It is not preferable because it is not possible.

Further, the addition amount of sintering aid, as oxide equivalent value of the sintering auxiliary component elements in the sinter, MgO 0.1 to 10 wt%, _{R 2} O is 0.1 to 10 wt %, Fe ₂ O ₃ is 0.1 to 1
It is preferably 0% by weight.
R ₂ O is a generic name for alkali metal oxides and can be represented by R ₂ O (wt%) = Na ₂ O (wt%) + 0.685 K ₂ O (wt%).
If MgO is smaller than 0.1% by weight, the effect as a sintering aid is not obtained, and if it is larger than 10% by weight, the effect as a sintering aid is not further increased. It is not preferable. When R ₂ O is less than 0.1% by weight, the effect as a sintering aid cannot be obtained. This is not preferable, and when it is more than 10% by weight, the generation of a liquid phase during sintering becomes abrupt. It is not preferable because stable operation cannot be performed. Fe ₂ O ₃ is 0.1% by weight.
If it is less than 10% by weight, it is not preferable because an effect as a sintering aid cannot be obtained. ,
Depending on the firing atmosphere or the like, it is not preferable because O ₂ is released and a large number of bubbles are generated in the sintered product.

Mixing with the above-mentioned main raw material consisting of waste or the like, or the above-mentioned component adjusting agent and / or sintering aid added to the main raw material as necessary is a known mixing such as a Nauter mixer or an air blending silo. What is necessary is just to perform by a machine, and any of a continuous type and a batch type may be used. In short, it is only necessary to obtain a homogeneous mixture, and the mixing time and the like may be appropriately set according to the equipment to be used, but if the mixing of the raw materials becomes insufficient, a good fired product cannot be obtained. It is necessary to pay attention.

In addition, when using raw materials with a coarse particle size or when it is desired to increase the mixing degree, a tube mill or the like may be used, and any known crusher may be used, regardless of whether it is a continuous type or a batch type. Can also be used. The pulverization and mixing time is preferably about 30 minutes to 1 hour from the viewpoint of economy and mixing properties, but may be appropriately set according to the equipment used.

The mixed raw material may be put in the powder kiln from the kiln bottom of the rotary kiln, but it is necessary to consider dust generation and the surrounding environment, such as when pouring into the kiln through a belt feeder from an outdoor hopper. In this case, or when there is a possibility of causing a problem in handling, the powdery raw material may be sized to 5 mm or less and charged into the rotary kiln.

At this time, there is no particular problem even if a pan pelletizer or an extrusion molding machine is used for sizing, but these are not preferable from the viewpoint of skill required and equipment cost, for example, using a bag mill or screw feeder. However, it is recommended that the facility can be simplified by directly sprinkling the raw material transport route or the raw material being sized, and this special skill is not required. In addition, the control of the particle size of the sized product can be adjusted by the amount of water spray, and the optimum water spray amount varies depending on the fineness and water content of the raw material. good. As long as the sized product is 5 mm or less, any shape may be used, and after sizing, a product adjusted to 5 mm or less by crushing or classification may be used. If this sized product exceeds 5 mm, it is difficult to uniformly sinter up to the inside, which is not preferable.

The powdery raw material thus mixed or the granular raw material adjusted to a size of 5 mm or less is fed from the kiln bottom of the rotary kiln and fired.

On the other hand, in the present invention, the adjusted raw material is charged from the kiln bottom of the rotary kiln, and the raw material having a melting point lower than that of the raw material charged from the kiln bottom is blown from the front of the rotary kiln.

The raw material blown from the front of the kiln is easily melted in the rotary kiln when the raw material is blown from the front of the kiln, acting as a binder for bonding the raw materials together, covering the surface of the raw material or the granulated product, From the viewpoints of filling the gaps between particles, helping granulate the raw materials introduced from the kiln bottom of the rotary kiln, and contributing to higher strength and lower water absorption of the granulated product. More than the melting point temperature of the raw material to be added more than 30
It is preferable that the melting point is lower by -100 ° C. When the melting point temperature difference exceeds 100 ° C., the raw material supplied from the kiln kiln bottom is not sufficiently baked, resulting in a brittle sintered product.
On the other hand, when the melting point temperature difference is less than 30 ° C., the raw material blown from before the kiln cannot fulfill the above-mentioned effects and effects, and a large amount of fused material is generated, so that stable operation of the kiln cannot be expected.

The particle size of the raw material blown from before the kiln is preferably 10 to 300 μm in terms of average particle size, and particularly preferably 30 to 100 μm in terms of average particle size. When larger than 300 micrometers, what adjusted the particle size by grinding | pulverization or classification can be used. When the particle size of the raw material blown from the front of the kiln is smaller than 10 μm, the cost for pulverization and the like rises, and the fear of scattering out of the system together with the exhaust gas is not preferable. Conversely, 300
When it exceeds μm, it is difficult to blow from the front of the kiln, and the mixing with the raw material charged from the kiln bottom is deteriorated, so that it is not possible to achieve the above-described action as a binder, covering action, filling action, etc. Absent.

Moreover, it is preferable that the blowing amount of the raw material blown from before a kiln is 5 to 15 weight% of the charging amount of the raw material thrown from the kiln bottom of a rotary kiln. This is because if the blowing amount is less than 5% by weight, the effect of reducing the firing temperature does not appear, and if the amount exceeding 15% by weight is blown, a large amount of fused material is generated, and stable operation of the rotary kiln cannot be expected. .

In addition, as a method of blowing the raw material from before the kiln, various known methods can be adopted, for example, a method of blowing the raw material together with compressed air through a supply pipe can be adopted. Near the maximum temperature, ie near the burning point (generally 2
It is preferable to blow in from one or more places toward the raw material of ˜3 times the length position).

The raw material blown from before the kiln of the rotary kiln is not particularly limited as long as it satisfies the above-mentioned properties, particularly the melting point temperature, but from the viewpoint of mass use of waste, etc. In the same way as the raw materials introduced from the kiln bottom, one or more selected from construction generated soil, industrial waste, general waste, and crushed stone from the quarry are used as main raw materials, and the components are adjusted as necessary for the main raw materials. It is preferable that an additive and / or a sintering aid are added and mixed to be adjusted to a predetermined chemical composition and melting point temperature. In this case, the target raw material chemical composition includes a firing temperature (melting point temperature) and an easy melting point. from the viewpoint of sintering property, CaO 5 to 15 wt%, SiO ₂ 50 to 60 wt%, _Al 2 O
It is preferable to adjust so that ₃ is contained in an amount of 20 to 30% by weight.

Needless to say, the use of rotary kilns for the firing of raw materials such as waste is recommended in the cement industry from the viewpoint of utilization of idle equipment, but rotary kilns are made of a stable quality sintered product. In addition to being easy to obtain and suitable for industrial production, combined with the above-mentioned blending adjustment of raw materials and the synergistic effect of blowing raw materials with low melting point temperature from before the kiln, It can be manufactured.

Firing using a rotary kiln is preferably 800-1500 ° C., more preferably,
Although it is performed at 1150 to 1350 ° C., the melting point temperature of the raw material blown from before the kiln and the desired quality of the sintered product (for example, absolute dry density, water absorption rate, etc.) may be taken into consideration.
A firing temperature of less than 800 ° C. is not preferable because sufficient firing is not performed and the raw material is discharged without being granulated. On the other hand, when the temperature exceeds 1500 ° C., a large amount of fusion material is generated, which is not preferable because it hinders operation.

Here, the rotary kiln to be used is a material circulation preheating facility such as a cyclone in the exhaust system,
A pre-heater, a waste heat boiler, etc. may or may not be attached. Moreover, what provided the lifter in the kiln bottom, and what added the process of squeezing the inner diameter of a rotary kiln on the way, or expanding may be used.

As fuel, if it is generally used such as heavy oil, pulverized coal, reclaimed oil, LNG, NPG, etc., it may be used alone or in a mixed firing, and the amount of pouring is adjusted so that a predetermined firing temperature is achieved. To do. In recent years, in plastic kilns, waste plastics, waste tires, waste wood, meat and bone powder and the like have been used as fuel substitutes, but such may be used as part of the fuel.

The firing time in the rotary kiln is suitably about 15 to 120 minutes from the viewpoint of economy, but may be appropriately prepared so as to obtain a sintered product of a predetermined quality. Further, the O ₂ partial pressure in the rotary kiln at the time of firing may be adjusted to 3 to 12% which is a general firing range, but is not particularly limited. In addition, when firing in a rotary kiln that is not equipped with a material circulation system such as a cyclone, it is better to adjust the draft so that the wind speed of the rotary kiln kiln bottom is approximately 5 m / sec or less, and the wind speed of the rotary kiln kiln bottom is 5 m / sec. sec
Exceeding the amount is not preferable because a large amount of raw material scatters out of the system and the yield of the sintered product decreases.

According to the method for producing a sintered product according to the present invention described above, the firing temperature of the raw material charged from the kiln bottom of the rotary kiln can be kept low, and the occurrence of coaching in the kiln can be prevented. Further, by adjusting the amount of raw material blown from before the kiln of the rotary kiln, it is possible to prevent abnormal fusion of the raw material, and there is no need to separately blow a fusion preventing material or the like.

By baking the raw material with the rotary kiln as described above, the absolute dry density is 1.0 g / cm.
^A sintered product having a water absorption of ³ or more, 2.5 g / cm ³ or less, a 24-hour water absorption, a reduced-pressure water absorption of 0.1% or more and 15% or less, and a crushing load of the sintered product of 0.5 kN or more is obtained.

The sintered product obtained by the production method according to the present invention is not only low in water absorption for 24 hours but also low in water absorption under reduced pressure, and has the above-described 24-hour water absorption and reduced water absorption of 0.1. %
Of course, a sintered product of 15% or less can be obtained. Both the 24-hour water absorption rate and the reduced-pressure water absorption rate are 0.1% or more and 6% or less, and the crushing load of the sintered product is 1.0 kN or more. A sintered product can also be easily obtained.

Here, the reduced-pressure water absorption is a method of forcibly absorbing water under a certain reduced pressure. Specifically, the sintered product is submerged in a sealed container, and the container is decompressed to −400 mmHg with a vacuum pump. And
It is a value obtained by measuring the water absorption at the time of depressurization from the amount of water contained in the sintered product after being left to stand for 15 minutes and then gradually opened to the atmosphere.
This reduced water absorption rate is an index for estimating the water absorption rate of the aggregate in the pipe when pumping concrete, and when using a sintered product as an aggregate for concrete, In order to ensure good workability, it is important for the sintered product to reduce not only the water absorption rate for 24 hours but also the water absorption rate under reduced pressure.

In the case of conventional pellet firing in which firing of only the surface is easy to proceed, even if the appearance is dense, firing unevenness is often generated inside the sintered product, and thus the water absorption rate is low for 24 hours. In general, the vacuum water absorption increases, but the sintered product obtained by the present invention melts the low-melting-point raw material blown from the front of the rotary kiln in the firing process, and acts as a binder. 24 hour water absorption rate, to fulfill the action, filling action to fill the gaps between particles, help granulate the raw material put in from the kiln bottom of the rotary kiln, and contribute to the high strength and low water absorption of the granulated product However, it has a characteristic that the low-pressure water absorption rate is low at the same time, and the strength is also provided. In addition, since it is put into a rotary kiln in a powdery and / or granular state of 5 mm or less, there is a feature that organic substances contained in main raw materials such as waste are easily burned during firing, and sintering during firing. Foaming of the product is suppressed,
As a result, it is easy to obtain a sintered product having a high dry density.

In addition, the sintered product has at least anorthite (CaO.2SiO ₂ .Al as a mineral species).
₂ O ₃ ) is preferably contained. This sintered product is mainly composed of silicate mineral,
Although it is made of anorthite and glass, the waste that is the raw material for sintered products is composed of several types of silicate minerals. These silicate minerals react with each other to produce glass as a binder phase. To do. Furthermore, the anorthite which is a strong mineral substance precipitates by reaction with this glass and a silicate mineral, and mainly interposes between glass and a silicate mineral. High strength can be expressed by the presence of anorthite, which is a strong mineral substance.

The content of anorthite in the product phase is 15 to 50% by weight, more preferably 20%.
-40% by weight. If the content of anorthite is less than 15% by weight, the ratio of the bonding between the silicate mineral particles being increased by the glass is increased, so that a high bonding strength cannot be obtained and the strength of the sintered product is lowered, which is not preferable. On the other hand, if it exceeds 50% by weight, it is not preferable because the crystalline phase increases and it becomes difficult to maintain the easy baking property.

Further, the chemical composition of the sinter, CaO 5 to 30 wt%, SiO ₂ 30 to 70 wt%,
Al ₂ O ₃ is preferably 10 to 40% by weight.
This is because the sintered product having such a chemical composition has good calcination properties, and has the above-described properties, that is, a high dryness density and a high crushing load, and a good property in which both the 24-hour water absorption rate and the reduced-pressure water absorption rate are low. It is preferable because it becomes a sintered product.

As described above, according to the present invention described in detail, since a sintered product having high strength and low water absorption can be obtained, it is suitable as an aggregate for concrete, a roadbed material, a backfill material, a substitute for clay as a cement raw material, and the like. It can be used, and since wastes such as construction waste and industrial waste are used as the main raw material, it can be used effectively as waste and idle rotary kilns can be used as they are. Also from the viewpoint, the invention has excellent effects.

Test example

[Test Examples 1 to 10]
Table 1 shows the chemical composition of the wastes used in the test (construction generated soil, sewage sludge, coal ash).
Table 2 shows the chemical compositions of the component modifiers used in the test (calcium carbonate, ordinary Portland cement, bentonite) and the sintering aid (ferronickel slag).

The raw materials shown in Table 1 and Table 2 above are weighed at various ratios shown in Table 3 and blended into the preferred range of the chemical composition of the present invention, and the metered raw material is charged into an air blending silo of 130 m ³ with 80 tons. Then, the aeration mixing with air was performed for 6 hours each, and the raw materials A to E fed from the kiln bottom of the rotary kiln were adjusted.
Table 3 shows the melting point temperatures of the adjusted raw materials A to E.

On the other hand, the raw materials shown in Table 1 and Table 2 are weighed at various ratios shown in Table 4, and the melting point temperature is 30 to 100 ° C. lower than the melting point temperature of the raw material charged from the kiln bottom. It mix | blended with the chemical composition of the range, this measuring raw material was mixed by the method similar to the above, and the raw material ae injected from the kiln of a rotary kiln was adjusted.
Table 4 shows the melting point temperatures of the adjusted raw materials a to e.

Subsequently, as shown in Test Examples 1 to 5 in Table 5, the raw materials A to E prepared as raw materials to be fed from the kiln butt are supplied to a rotary kiln having an inner diameter of 1.5 m and a length of 20 m at 1 ton / hr. The raw materials a to e adjusted as raw materials to be blown in front of the kiln,
A fuel oil A is burned so that a dense sintered product can be obtained under the condition that a predetermined amount of each is blown to the burning point together with compressed air from the front of the kiln of the rotary kiln toward the burning point. Baking while adjusting the amount.
As shown in Table 5, the firing temperature is about the melting point temperature of the raw material blown from before the kiln, and the amount of the raw material blown from before the kiln is the amount blown while observing the state of the sintered product discharged from the kiln. Were adjusted to the amounts shown in Table 5.

On the other hand, for comparison, as shown in Test Examples 6 to 10 in Table 5, the raw materials A to E prepared as raw materials to be fed from the kiln bottom were supplied to the same rotary kiln with a supply amount of 1 ton / hr. A dense sintered product can be obtained under the condition that 5% by weight of the raw material charged from the kiln butt is blown in from the kiln butt, and 5% by weight of the raw material charged from the kiln butt as the anti-fusion material before the kiln. It baked, adjusting the amount of fueling of A heavy oil which is a fuel so that it might be.
As shown in Table 5, the firing temperature was about the melting point temperature of the raw material charged from the kiln bottom.

All of the sintered products thus obtained were dense in appearance.
The obtained sintered product was sieved with a sieve having openings of 5, 10, 15 mm, and 5-10 mm,
With respect to the sintered product of 10 to 15 mm, the chemical composition was determined by quantitative analysis of fluorescent 10 rays, and the absolute dry density and water absorption were measured according to JIS A 1110. In conjunction with this,
In order to measure the reduced-pressure water absorption rate of water absorbed for 15 minutes under a reduced pressure of 400 mmHg, and to measure the strength of the sintered product, the crushing load was applied in accordance with the crushing load test method for high-strength fly ash artificial aggregates of Japan Was measured. Further, this sintered product was pulverized, and the amount of anorthite produced was quantitatively analyzed by an internal standard method (internal standard material; CaF ₂ ) using a powder 10-line diffractometer.
The results are shown in Table 6.

As is apparent from Table 6, the sintered products of Test Examples 1 to 5 in which the raw material having a low melting point was blown from before the kiln had a low firing temperature, but the sintered products of Test Examples 6 to 10 Quality (absolute density, 24
It was found that there is no inferiority to the time water absorption rate, the reduced pressure water absorption rate and the crushing load), and that a high-quality sintered product can be produced efficiently at low cost.

Claims (7)

One or more selected from construction waste soil, industrial waste, general waste, and crushed stone from a quarry is used as a main raw material, and component adjusters and / or sintering aids are added to the main raw material as necessary. Then, after adjusting to the predetermined chemical composition, the adjusted raw material is charged from the kiln bottom of the rotary kiln in a powder and / or granular state of 5 mm or less, and the raw material having a melting point lower than the raw material charged from the kiln bottom The powder is blown in front of the kiln of the rotary kiln and fired while mixing both raw materials with the rotary kiln. 2. The method for producing a sintered product according to claim 1, wherein the melting point temperature of the raw material blown from before the kiln of the rotary kiln is lower by 30 to 100 ° C. than the melting point temperature of the raw material charged from the kiln bottom of the rotary kiln. The amount of the raw material blown from before the kiln of the rotary kiln is 5 to 15% by weight of the amount of the raw material charged from the bottom of the rotary kiln.
The manufacturing method of the sintered compact as described in 2. The raw material blown from before the kiln of the rotary kiln is one or more selected from construction generated soil, industrial waste, general waste, and crushed stone from a quarry, and a component adjuster for the main raw material as necessary. The method for producing a sintered product according to any one of claims 1 to 3, wherein a sintering aid is added and mixed to adjust to a predetermined chemical composition and melting point temperature. It is a sintered product mainly composed of at least one selected from construction generated soil, industrial waste, general waste and quarry debris, and has an absolutely dry density of 1.0 to 2.5 g / cm ^3. A sintered product having a 24-hour water absorption rate and a reduced-pressure water absorption rate of 0.1% to 15% and a crushing load of 0.5 kN or more. The sintered product according to claim 5, comprising 5 to 30% by weight of CaO, 30 to 70% by weight of SiO ₂ , and 10 to 40% by weight of Al ₂ O ₃ . It contains at least 15 to 50% by weight of anorthite as a mineral species,
The sintered product according to claim 5 or 6.