JP2005306707A - Method for manufacturing sintered body and sintered body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a high quality sintered body in a good productivity while eliminating a complicated process in the manufacturing of the sintered body using waste, or the like, as a main raw material. <P>SOLUTION: In the method for manufacturing the sintered body, one or more materials selected among the soil generated by construction, industrial waste or general waste are used as the main raw material, and the main raw material is adjusted to a mixed raw material having a prescribed chemical composition by adding and mixing a component control material and/or a sintering aid to the main raw material if necessary, then the mixed raw material is introduced into a rotary kiln in the powdery and/or granular state of 5 mm or less size and burned while granulating. <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 used. However, in recent years, the landfill disposal site on the receiving side has become increasingly depleted and cannot accept all the generated waste.
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.

  Also, in the cement industry, industrial waste is being used as a raw material substitute for cement, but in order to obtain a cement clinker of a prescribed quality, the type and amount of industrial waste that can be used is also limited. In addition, due to the impact of reduced production due to the recent slump in cement demand, the amount of industrial waste generated has not caught up.

In addition, as mentioned above, the decline in cement demand in recent years is a serious problem for the cement industry, and the production capacity of cement for the recent cement demand, that is, the existing production facilities is excessive, so it must be stopped. First, rotary kilns etc. have been made idle, but the facilities are drastically remodeled and diverted to other production equipment.For example, municipal waste is fermented to produce cement raw materials. A policy to be utilized as a part has been proposed (for example, Patent Document 2).
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.

On the other hand, natural aggregates and sand are used for conventional concrete aggregates, but their production is tight year by year, and in some areas, high quality products cannot be obtained, and there are materials that can replace them. It is strongly desired.
In addition, from the viewpoint of natural resources and environmental protection, implementation of such measures is desired.

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

  The present invention has been made in view of the problems and demands of the above-described background art, and its purpose is to enable large-scale use of construction generated soil, industrial waste, or general waste. When manufacturing sintered products using wastes of the above as raw materials, idle facilities or existing facilities can be used as they are, methods for producing high-quality sintered products with good productivity, eliminating complicated processes, and waste It is to provide a high-quality sintered product made mainly of

  As a result of intensive studies in order to solve the above-mentioned 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 raw material is in a powder form or formed into a predetermined granular shape and fired with a rotary kiln, so that it has an appropriate size and is fully sintered to the inside. The present inventors have found that a high-quality sintered product can be obtained and completed the present invention.

That is, the present invention uses at least one selected from construction generated soil, industrial waste, or general waste as a main raw material, and a component adjusting agent and / or a sintering aid is added to the main raw material as necessary. After mixing and adjusting to a raw material having a predetermined chemical composition, the raw material was put into a rotary kiln in a powder and / or granular state of 5 mm or less, and a method for producing a sintered product that was fired while granulating was used.
The construction generated soil, industrial waste, or general waste used in the present invention preferably contains CaO, SiO ₂ , Al ₂ O ₃ in total of 50% by weight or more as the content excluding moisture. .

Here, the chemical composition of the raw material is preferably adjusted so that CaO is 5 to 30% by weight, SiO ₂ is 30 to 70% by weight, and Al ₂ O ₃ is 10 to 40% by weight. The particle size of the main raw material consisting of waste and the component modifier and / or sintering aid added to and mixed with the main raw material as required is preferably 1 to 300 μm in average particle size, especially Preferably have an average particle size of 1 to 50 μm. Further, for the purpose of enabling stable firing, it is preferable to blow an anti-fusing material into the rotary kiln and attach it to the granulated product during rolling and granulation.

In addition, the present invention is a sintered product mainly composed of one or more selected from construction generated soil, industrial waste, or general waste, and has an absolutely dry density of 1.0 to 2.5 g / cm. ³ , 24-hour water absorption and reduced-pressure water absorption are 0.1 to 15%, particularly 0.1 to 6%, the crushing load of particles having a diameter of 5 to 10 mm is 0.2 kN or more, particularly 0.5 kN or more, Alternatively, a sintered product in which the crushing load of particles having a diameter of 10 to 15 mm is 0.5 kN or more, particularly 1.0 kN or more.

Here, the sintered product preferably contains at least 15 to 50% by weight of anorthite as a mineral species. Further, the sintering was, CaO 5 to 30 wt%, a SiO ₂ 30 to 70 wt%, it is preferable that the Al ₂ O ₃ containing 10 to 40 wt%.

  According to the above-described method for producing a sintered product according to the present invention, since granulation is performed by rolling with a rotary kiln, a complicated molding process for previously molding a raw material such as waste into a predetermined size can be omitted, Since firing is performed in the form of particles or small particles, a so-called burnt state hardly occurs, and there is an effect that a sintered product having high strength and low water absorption can be produced with high productivity.

  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 by 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, iron sludge, etc.), construction wastes, concrete wastes, boring waste soil, various incineration ash (for example, coal Ash, incinerated fly ash, molten fly ash, etc.), foundry sand, rock wool, waste glass, blast furnace secondary ash, and the like. Further, examples of the general waste used in the present invention include sewage sludge, sewage sludge dry powder, sewage sludge incineration ash, municipal waste incineration main ash, municipal waste incineration fly ash, and shells.
In the present invention, at least one selected from the above-mentioned construction generated soil, industrial waste, or general waste is used as a main raw material.
Hereinafter, one or more types selected from construction generated soil, general waste, and industrial waste may be referred to as waste.

  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. Wastes and the like may be used after drying with a dryer such as a rotary dryer before and after pulverization.

  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 powder or a particulate state 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 large-scale use of waste, etc., it is preferable not to use component modifiers and / or sintering aids as much as possible. For this purpose, the above-mentioned construction generated soil, general waste, and industrial waste are appropriately combined. It is preferable that the chemical composition of the waste material, which is 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.

The chemical composition of the target raw material is preferably adjusted so that CaO is contained in an amount of 5 to 30% by weight, SiO ₂ is contained in an amount of 30 to 70% by weight, and Al ₂ O ₃ is contained in an amount of 10 to 40% by weight.
This is 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 sinterability. On the other hand, if CaO is contained in an amount of more than 30% by weight, the firing temperature rises and the sinterability deteriorates, which is not preferable. Further, if the SiO ₂ content is less than 30% by weight, the firing temperature rises and the sinterability deteriorates, which is not preferable. If it exceeds 70% by weight, the firing temperature rises remarkably and is not practical. It is not preferable. If Al ₂ O ₃ is less than 10% by weight, it is not preferable because stable operation such as generation of a large amount of liquid phase becomes difficult. If Al ₂ O ₃ is present in an amount exceeding 40% by weight, the firing temperature is remarkably high. It is not preferable because it rises and is not practical.

Here, examples of the component adjusting agent include silica powder, clay, kaolin, bentonite and the like as the SiO ₂ source. Examples of the Al ₂ O ₃ source include alumina powder, aluminum ash, and examples of the CaO source include limestone powder, slaked lime, quicklime, cement, and gypsum.

About the particle size of the said component regulator, it is preferable that it is 1-300 micrometers by average particle diameter from the reactivity with a waste etc., and it is especially preferable that it is 1-50 micrometers by average particle diameter. When larger than 300 micrometers, what adjusted the particle size by grinding | 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 the waste and the like is remarkably deteriorated, and the effect as a component modifier is obtained. Not preferred because

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

There are various sintering aids. For example, among the above-described component modifiers, clay, kaolin, bentonite, various Al ₂ O ₃ sources and cements, etc. have an effect of promoting sintering. I have a match. MgO also has an effect of promoting sintering. Mg (0H) ₂ , MgCO ₃ , CaCO ₃ · MgCO ₃ (dolomite), MgO · Al ₂ O containing MgO as well as MgO are of course included. ₃ (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.
In addition, Fe-containing oxides and composite oxides, such as Fe ₂ O ₃ powder and iron powder, have the effect of promoting the sintering reaction, so these may be added as necessary.

  The particle size of the sintering aid to be added is preferably 1 to 300 μm in average particle size, and more preferably 1 to 50 μm in average particle size, due to reactivity with waste and the like. When larger than 300 micrometers, what adjusted the particle size by grinding | pulverization etc. 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 the waste etc. becomes worse, and the effect as a sintering aid 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 preferably 0.1 to 10% by weight.
R ₂ O is a general term 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, generation of a liquid phase during sintering becomes abrupt. It is not preferable because stable operation cannot be performed. On the other hand, if Fe ₂ O ₃ is less than 0.1% by weight, the effect as a sintering aid cannot be obtained, which is not preferable. If it is more than 10% by weight, a liquid phase is generated during sintering. Depending on the abruptness and the inability to perform a stable operation, or the firing atmosphere, O ₂ is released and a large number of bubbles are generated in the sintered product.

  Mixing with the main raw material consisting of the above-mentioned waste or the like, or a component adjusting agent and / or a sintering aid added to the main raw material as necessary is a known mixer such as a nauter mixer or an air blending silo. In this case, either a continuous type or 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. However, if mixing is insufficient, the best precautions are obtained because a good sintered product cannot be obtained. Need to pay.

  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 is put into a rotary kiln in a powder and / or granular state of 5 mm or less, and sintered while being granulated to produce a sintered product.

  The raw material may be put into the rotary kiln in the powder state, but when dust generation and the surrounding environment need to be taken into consideration, such as when sending it to the kiln via a belt feeder from an outdoor hobber, or hand linking If there is a possibility of causing a problem in terms of surface, the raw material powder 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 the 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 optimal water spray amount varies depending on the fineness and water content of the raw material powder. 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 the interior, which is not preferable.

The powdery raw material thus mixed or the granular raw material adjusted to 5 mm or less is fired in a rotary kiln.
Needless to say, the use of a rotary kiln is recommended in the cement industry from the viewpoint of effective utilization of idle equipment, but a rotary kiln is suitable for industrial production because it is easy to obtain stable quality sintered products continuously. In addition, it is possible to manufacture a sintered product extremely stably by combining the above-described synergistic effect by adjusting the blending of raw materials.

Firing using a rotary kiln is preferably performed at 800 to 1500 ° C., more preferably 1150 to 1350 ° C., taking into account the quality of the desired sintered product (eg, absolutely dry density, water absorption rate, etc.) It is good to prepare appropriately.
A firing temperature of less than 800 ° C. is not preferable because sufficient firing is not performed and the raw material may be discharged without being granulated. Moreover, when it exceeds 1500 degreeC, a raw material will fuse | melt and it is unpreferable since it will interfere with a driving | operation.

  The rotary kiln used here may or may not be provided with a material circulation preheating facility such as a cyclone, a preheater, a waste heat boiler, or the like in the exhaust system. Moreover, what provided the lifter in the kiln bottom, and what added processing, such as narrowing or expanding the internal diameter of a rotary kiln on the way, may be used.

  As fuel, if it is generally used such as heavy oil, pulverized coal, reclaimed oil, LPG, NPG, etc., it can be used alone or in a mixed firing, and the amount of pouring is adjusted so that the predetermined firing temperature is reached 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. The O ₂ partial pressure in the rotary kiln during 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 does not have 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 / s or less, and the wind speed of the rotary kiln kiln bottom is 5 m / s. If it exceeds s, a large amount of raw material scatters out of the system and the yield of the sintered product decreases, which is not preferable.

During firing, for the purpose of improving the quality of the sintered product and for the purpose of more stable operation, an anti-fusing material may be blown from before the kiln of the rotary kiln, and a sintered product of the desired quality has already been obtained. If there is a stable operation, it is not necessary to use an anti-fusing material.
As the anti-fusing material, quartzite, alusite, alumina, cement powder, alite, belite powder, etc., which are the main minerals of cement, can be used.

  When the particle size of the anti-fusing material is approximately 10 to 1000 μm in average particle size, the anti-fusing effect is easily obtained, and the higher the purity, the better. If the average particle size of the anti-fusing material is smaller than 10 μm, it is highly likely that it will be used as a raw material during firing and incorporated into the sintered product, and the effect as an anti-fusing material will be reduced, This is not preferable because it causes a reduction in quality. On the contrary, if the average particle diameter of the anti-fusing material is larger than 1000 μm, it is not preferable since the wear of the feeding site and the like is remarkable and the exchange of these consumable sites and parts is frequent. Further, if the average particle diameter of the anti-fusing material exceeds several millimeters, the effect as the anti-fusing material is reduced, and separation from the material fused to the sintered product becomes difficult.

The method of blowing the anti-fusing material is not particularly limited as long as a predetermined amount of the anti-fusing material can be sprayed on the burning point. For example, a feed pipe such as a water-cooled tube or an air-cooled tube is inserted before the kiln of the rotary kiln. However, if the anti-fusing material is sprayed by a pneumatic pump such as an ejector or a transport pump such as a mono pump, the apparatus can be simplified and recommended.
Further, the blowing amount of the anti-fusing material is preferably 3 to 10% by weight with respect to the mixed raw material fed into the rotary kiln, and if it is less than 3% by weight, it is difficult to obtain the effect as the anti-fusing material. Even if it exceeds the weight percent, the anti-fusing effect of the anti-fusing material does not increase any more, which is not preferable from an economical viewpoint.

By firing the raw material with the rotary kiln as described above, the absolutely dry density is 1.0 g / cm ³ or more, 2.5 g / cm ³ or less, the water absorption rate for 24 hours, the reduced pressure water absorption rate is 0.1% or more, 15% or less, A sintered product having a crushing load of 0.2 kN or more of a sintered product having a diameter of 5 to 10 mm or a crushing load of a sintered product having a diameter of 10 to 15 mm of 0.5 kN or more is obtained.

This sintered product according to the present invention is characterized by not only low water absorption for 24 hours but also low water absorption under reduced pressure, and the above-described 24-hour water absorption and vacuum water absorption are 0.1% or more and 15%. Of course, it is possible to obtain a sintered product of the following: 24 hour water absorption and reduced pressure water absorption are both 0.1% or more and 6% or less, and the crushing load of the sintered product having a diameter of 5 to 10 mm is 0.5 kN or more. Alternatively, a sintered product having a crushing load of 1.0 kN or more of a sintered product having a diameter of 10 to 15 mm can be easily obtained.
Here, the reduced-pressure water absorption is a method of forcibly absorbing water under a constant reduced pressure. Specifically, the sintered product is submerged in a sealed container, and the inside of the container is -400 mmHg with a vacuum pump. This 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 gradually reducing the pressure and allowing to stand for 15 minutes.
This reduced water absorption rate is an index for inferring the water absorption of the aggregate in the pipe when pumping concrete, and when using the 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 24-hour water absorption rate but also the reduced-pressure water absorption rate.

  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, however, the sintered product obtained by the present invention grows while the molten particles as a core entrain other molten particles in the firing process, and the degree of sintering is increased. Since the firing proceeds while increasing the temperature, a very homogeneous and dense sintered product with very little unevenness of firing from the surface to the inside can be obtained. Therefore, not only the water absorption rate for 24 hours is low, but also the water absorption rate under reduced pressure is reduced 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. As a result, it is easy to obtain a sintered product having a high dry density.

In addition, the sintered product according to the present invention preferably contains at least anorthite (CaO.2SiO ₂ .Al ₂ O ₃ ) as a mineral species.
This sintered product is mainly composed of silicate mineral, anorthite, and glass, but the waste that is the raw material of the sintered product is composed of several types of silicate minerals. The silicate minerals react with each other to produce glass as a binder phase. 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 produced phase is 15 to 50% by weight, more preferably 20 to 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, making it difficult to maintain the sinterability.

The chemical composition of the sinter according to the present invention, CaO 5 to 30 wt%, SiO ₂ 30 to 70 wt%, it is preferable Al ₂ O ₃ is 10 to 40 wt%.
This is because the sintered product having such a chemical composition has good sinterability and has the above-described properties, that is, a high dry density and a high crushing load, and a low property for both the 24-hour water absorption rate and the reduced-pressure water absorption rate. This is preferable because it has 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. Since it can be used, and since wastes such as construction generated soil and industrial waste are used as the main raw material, it is possible to use waste effectively and idle rotary kilns can be used as they are. Therefore, the invention has excellent effects.

Test example

[Test Examples 1 to 10]
Table 1 shows the chemical composition of wastes and the like used in the test (two types of construction generated soil, one type of sewage sludge, and two types of coal ash). Table 2 shows chemical compositions of the component preparation agents (limestone, calcium carbonate, ordinary portland cement, bentonite) and sintering aid (ferronickel slag) used in the test.

The raw materials shown in Table 1 and Table 2 are weighed at various ratios shown in Table 3, blended into the chemical composition within the preferred range of the present invention, and the metered raw material is put into a 130 m ³ air blending silo at 80 tons. The aeration mixing with air was performed for 6 hours each.
Subsequently, the obtained raw material is charged into a rotary kiln having an inner diameter of 1.5 m and a length of 20 m at 1 ton / h, and fuel is used so that a dense sintered product can be obtained under the condition that the residence time is 60 minutes. Firing was performed while adjusting the amount of A heavy oil. At this time, for the purpose of preventing fusion of the sintered product, silica powder having an average particle diameter of 30 μm was fired from the front of the kiln at 30 kg / h while being blown near the burning point.

The sintered product thus obtained was fine in appearance.
The obtained sintered product is sieved with sieves having openings of 5, 10 and 15 mm, and the sintered composition of 5 to 10 mm and 10 to 15 mm is subjected to a chemical composition by quantitative analysis of fluorescent 10 rays, respectively. Further, the absolute dry density and water absorption were measured according to JIS A 1110. In addition to this, in order to measure the reduced-pressure water absorption rate of water absorption for 15 minutes under a reduced pressure of −400 mmHg, and to further measure the strength of the sintered product, the test method for crushing load of high-strength fly ash artificial aggregates according to the Japan Society of Civil Engineers The crushing load was measured according to the above. The 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 4.

  As is clear from Table 4, in any of the test examples, a 24-hour water absorption rate and a reduced-pressure water absorption rate were both low, and a high-strength sintered product was obtained.

[Test Examples 11 to 14]
The raw materials used in the test are the same as in Test Examples 1 to 10, and the raw materials are weighed at the blending ratios shown in Table 5, and the measured materials are put into an air blending silo of 130 m ³ by 80 tons. The aeration mixing was performed for 6 hours each.
Subsequently, the obtained raw material is granulated into a spherical shape with a pan pelletizer so as to have a particle size of 5 to 15 mm, and the granulated product is cured at 60 ° C. for 3 hours to increase the strength of the granulated product. Increased.
Subsequently, a granulated product having a particle size of 5 to 15 mm is put into a rotary kiln having an inner diameter of 1.5 m and a length of 20 m at 1 ton / h, and a dense sintered product is obtained under the condition that the residence time is 60 minutes. It baked, adjusting the amount of fueling of A heavy oil which is a fuel so that it might be. At this time, for the purpose of preventing fusion of the sintered product, the silica powder having an average particle diameter of 30 μm was fired while being blown near the burning point at 30 kg / h from before the kiln.

The sintered product thus obtained was fine in appearance.
About the obtained sintered compact, it measured by the same method about the item similar to the said Test Examples 1-10.
The results are shown in Table 6.

  As is clear from Table 6, the absolute dry density and the 24-hour water absorption were inferior to those of the sintered products of Test Examples 1 to 10, but the crushing load and the vacuum water absorption were the above tests. It was inferior compared with the sintered compact of Examples 1-10.

[Test Examples 15 to 19]
Table 7 shows the chemical compositions of the construction-generated soil, sewage sludge, coal ash, and the three component modifiers (calcium carbonate, silica stone powder, and alumina powder) used in the test.

  Sintered materials were produced in the same manner as in Test Examples 1 to 10 except that the raw materials shown in Table 7 were weighed at the ratios shown in Table 8 and used as raw materials for producing sintered materials.

When the raw material having the blending ratio of Test Example 15 was used, the firing temperature was increased to 1150 ° C., but apparently only a burnt sintered product was obtained. Although it is considered that firing can be performed using a special rotary kiln, it has been found that the firing temperature is high and the production cost is inevitably increased, which is not practical.
When the raw materials having the blending ratio of Test Example 16 were used, the firing temperature was increased to 1550 ° C. as in the case of Test Example 15, but apparently only a burned sintered product was obtained, which was practical. It turns out that it is not.
When the raw material of the blending ratio of Test Example 17 was used, firing could not be controlled, for example, repeated running and melting during firing, and apparently only a burned sintered product was obtained.
When the raw material having the blending ratio of Test Example 18 was used, the firing temperature was increased to 1550 ° C., but apparently only a burnt sintered product was obtained. Although it is considered that firing can be performed using a special rotary kiln, it has been found that the firing temperature is high and the production cost is inevitably increased, which is not practical.
When the raw materials having the blending ratios of Test Example 19 were used, the firing temperature was increased to 1550 ° C. as in the case of Test Example 18 above. It turns out that it is not.

Claims (7)

  One or more selected from construction-generated soil, industrial waste, or general waste is used as the main raw material, and component adjusters and / or sintering aids are added to and mixed with the main raw material as required. A method for producing a sintered product, wherein the raw material is adjusted to a raw material having a composition, and then the raw material is put into a rotary kiln in a powdery and / or granular state of 5 mm or less and fired while granulating. The chemical composition of the raw material, CaO 5 to 30 wt%, SiO ₂ 30 to 70 wt%, Al ₂ O ₃ is equal to or is adjusted to 10 to 40 wt%, baked according to claim 1 A method for producing a knot.   The main raw material composed of one or more selected from the above-mentioned construction generated soil, industrial waste, or general waste, and the particle size of the above-mentioned component adjusting agent and / or sintering aid added to and mixed with the main raw material as necessary The average particle diameter is 1 to 300 μm, The method for producing a sintered product according to claim 1 or 2.   The method for producing a sintered product according to claim 1, 2 or 3, wherein an anti-fusing material is blown into the rotary kiln and adhered to the granulated product during rolling and granulation. Sintered material containing one or more selected from construction generated soil, industrial waste, or general waste as the main raw material, with an absolute dry density of 1.0 to 2.5 g / cm ³ , 24 hour water absorption And the reduced-pressure water absorption is 0.1% or more and 15% or less, the crushing load of particles having a diameter of 5 to 10 mm is 0.2 kN or more, or the crushing load of particles having a diameter of 10 to 15 mm is 0.5 kN or more. A sintered product characterized by   The sintered product according to claim 5, wherein the sintered body contains at least 15 to 50% by weight of anorthite as a mineral species. The CaO 5 to 30 wt%, a SiO ₂ 30 to 70% by weight, characterized by containing Al ₂ O ₃ 10 to 40 wt%, claim 5, or sintered product according to 6.