JPS6186459A - Manufacture of hardened body from fluidized bed incinerationash as main raw material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention consists of coal ash generated during fluidized+4 combustion in a fluidized bed consisting of coal as a fuel and limestone as a desulfurizing agent and a spent desulfurizing agent. A method for producing a cured product using a mixed powder as the main raw material, specifically, using the above mixed powder as the main raw material, adding more water than the plastic limit of the mixed powder and less water than the liquid limit to the mixed powder, and kneading it. After forming a granular material by doing this, it is pressure-molded at a pressure of 1 to 50% aG, and this molded product is cured (specifically, after moist air curing, it is treated with steam) to obtain a material with high mechanical strength. The present invention relates to a method for producing a water-conserving body.

Conventional technology In recent years, in Japan, due to the international oil supply and security instability since the oil crisis of 1973, the guaranteed availability of a large amount of oil has become 1,000 yen, and it is difficult to reduce the dependence on oil due to the energy supply and demand situation. The development of energy alternatives to petroleum has become a national issue, and stone-based energy is attracting attention as one of the pillars of energy.

Traditionally, the primary combustion method that uses stone as fuel has been the charcoal sintering method, but recently the fluidized bed combustion method has gained attention. This fluidized bed combustion method usually employs an in-furnace desulfurization method, in which coal as a fuel and limestone as a desulfurizing agent for in-furnace desulfurization are input to form a fluidized bed in a boiler. Compared to the conventional pulverized coal combustion method, the fluidized bed combustion method has the following advantages: firstly, the furnace trough is smaller and the boiler volume is smaller; secondly, there are fewer restrictions on the type of fuel coal and fewer ladles; Low-temperature combustion of 750 to 850°C is possible, and there is no problem with ash condensation.
Fourthly, the heat transfer water has the advantage that the overall HS41 series on the tube surface is large.

On the other hand, there is a problem with ash treatment in the practical application of fluid i/combustion wave radiation. The ash generated during fluidized bed combustion is composed of so-called coal ash and a spent desulfurization agent, and the spent desulfurization agent is composed of anhydrous gypsum, which is a desulfurization product, and unreacted quicklime. In order to increase the removal efficiency of sulfur oxides in coal combustion gas, that is, the desulfurization rate, the amount of limestone input is usually set so that the Ca/S molar ratio is 3 to 6, and the temperature is 750 to 850 °C. Upon reaction with sulfur oxides, limestone is discharged together with quicklime and type 1 water gypsum9, and coal ash. The amount of fluidized bed combustion ash generated varies considerably depending on the type of coal used, desulfurization rate, boiler operating conditions, etc., but normally, the amount of coal ash, type hydrogypsum, and quicklime generated is proportional to the amount of coal used. Approximately 15-20% by weight,
1-10% by weight, 1-10% by weight.

Problems to be Solved by the Invention Conventionally, most of the stone ash generated in Japan has come from charcoal combustion, and about 10 to 20% by weight of it has been recycled as fly ash for cement admixtures, cement raw materials, etc. The rest was abandoned in landfills K and Q. However, it is clear that it is not possible to adequately deal with the large amount of coal ash generated in the future, either by using it as a raw material for cement or by feeding it to village sites. be. In this way, even in the case of powdered coal and ash-pulling, the processing method for coal ash has changed significantly. Considering that an extremely large amount of fluidized bed combustion ash remains after one use of coal, establishing a unique disposal method for fluidized bed combustion ash is an extremely important issue for the practical application of fluidized bed combustion technology. In addition, in order to establish a mass disposal method for fluidized bed combustion ash, it is essential to effectively reuse it as a resource.First of all, in Japan, where domestically produced resources are scarce, this is not just a matter of disposal. This is based on the fact that reuse directly leads to resource and energy conservation, and secondly on the fact that there is extremely little environmental destruction.

In view of the above point, the present invention aims to utilize fluidized bed combustion ash in large quantities as a resource in the civil engineering and construction fields.
This work was done with the aim of producing a large cement-like hardened body of Kikutai Cloth iXE using 7-me incinerated ash as a raw material.

Means and action for solving the problems (Flow of the present invention)
・The manufacturing method for one hard carbon fiber using 4 combustion ash as the main raw material is We!
The coal ash and spent sulfur 4j generated during fluidized/Z-combustion in the fluidized bed are mixed with 60 to 85% by weight of coal ash, 10 to 25% by weight of lime, and 5 to 25% by weight of gypsum. Prepare a mixed powder by adding quicklime and/or slaked lime, as well as ■-type hydrated gypsum, hemihydrated gypsum, or/and dihydrated gypsum as needed, and add water to this mixed powder to match the mixing ratio. In the method of adding and kneading, and then curing, the plasticity limit of the mixed powder is exceeded, and water is added to the mixed powder, which is less than the liquid level and the eye level, and the particle size is 100% by weight or less, Particle size 10. 60-100% by weight of carbon dioxide or less, particle size of 5 mm or less, 40-100% by weight! name, particle size 1
After kneading into a kneaded material having a particle size distribution of 5 to 50% by weight below my, and a particle size of 0.1 to 10% by weight, 1 to 50
It is characterized by pressure molding with a pressure of 1G. After pressure molding, it is usually kept at room temperature to 60°C1 relative i! ! 1
More than 80% live for 5 to 25 hours, and 65 to 90 hours.
Treatment is performed with atmospheric pressure steam at a relatively low temperature of °C. The cured product obtained by treatment with steam at normal pressure may be pulverized into tear-like cured products with a particle size of 40 grains or less.

Hereinafter, the configuration of the present invention will be explained in detail. In general, the component composition, which is a typical property of fluidized twisted ash, largely depends on the type of stone used.First of all, the combustion residue, 5in2, Al2O3, C, qO, F, depends on the coal production pond.
The wet ratio of components such as e2O3, Na2O, and K2O differs, and secondly, the content of the desulfurization product, type 3-type gypsum, and the unreacted desulfurization agent, quicklime, differs depending on the sulfur content in the coal. . For this reason, when producing a high-strength hydration-hardened body by steam treatment using flow::・3P burnt ash as the main raw material, the hydration-hardened body is Appropriate manufacturing conditions are different. The main manufacturing conditions are: addition of quicklime and/or water gypsum when necessary, mixing conditions with water to give the kneaded product an appropriate particle size distribution, 1-shape conditions, and steam treatment. Time condition (temperature,
time), etc.

The relationship between the manufacturing conditions of a water-use hardening body using fluidized bed combustion ash as the main raw material and the properties of the water-use hardening body is generally the same.

Hydraulic hardening produced by steam treatment (the main component of the human body is water)
! J:/ Kite (8CaO-A1203・8Ca
SO4.32H20), various forms of calcium silicate hydrate (XCaO-YSj-02-ZH20), but the one that contributes the most to the strength (-) is ettringite.

First, when the content of type water gypsum and/or quicklime content in the raw material mixed powder is low, calcium monosulfo aluminate (A, 03, CaSO4, 12H20) becomes the main component of the water hardening material. Although the strength is low, as the content of type (1) water gypsum and/or the quicklime content increases, the amount of ettringite increases and the strength of the hydrated hardened product also increases. Furthermore, when the content of old type, gypsum gypsum and/or quicklime increases, free gypsum and/or slaked lime that does not participate in the reaction occurs during steam treatment, resulting in a decrease in the strength of the hydrated hardened product. Optimal perspiration ratio that maximizes the mechanical strength of the water-cured material by steam treatment: ``i'', coal ash content other than quicklime and ■ type water gypsum: 60-85% by weight, quicklime content: 10-25% by weight, 11 Monk anhydrite is 5 to 25% by weight. When the quicklime needle and/or +15 anhydrite content is less than the maximum.
In addition, type 11 (1) requires addition of plaster.

Slaked lime may be used as a substitute for quicklime for the 1-sake festival, and ll type, -#. Hemihydrate gypsum and/or dihydrate gypsum may be used instead of hydrogypsum. In addition, slaked lime! If the blending ratio exceeds 30%, a large amount of slaked lime will leak out after steaming, and in a dry atmosphere, the slaked lime will turn into charcoal and calcium, and the resulting reaction will cause hair cracks ( Microcracks) occur and product quality deteriorates.

On the other hand, crosstalk conditions and molding conditions also have an effect on the thickness of the hydrated hard body. Under cross-wire conditions, if the added water is less than the plasticity limit of the mixed resin, the Roux 6 strength will not be achieved regardless of the molding conditions. This is the 11th history of fluidized bed combustion.
I response is through solution reaction (TLhrO
This is because the water utilization reaction will not proceed sufficiently unless there is sufficient pore water. If the amount of added water is still higher than the liquid limit of the mixed powder, pressure molding will be difficult; a high-strength cured product can be produced by injection molding or pour molding, but a mold is required because the molded product has fluidity. However, the manufacturing process is complicated and mass production on an industrial scale is not possible. For this reason, in order to mass-produce molded bodies capable of forming high-strength cured bodies on an industrial scale, the amount of water added must be greater than the plastic limit of the mixed powder and less than the liquid limit. Furthermore, if the particle size of the kneaded product is outside the range of the particle size distribution, it is impossible to produce a molded product that can be made into a high-strength cured product at a low pressure of 1 to 50% aG. In other words, when the particle size distribution is larger than the above particle size distribution, the molded product has many large voids and does not exhibit high strength, and when it is on the small side, the bulk density of the molded product is small and high. In order for a molded product under a pressure of 1 to 50% aG to develop high strength by steam treatment without developing strength, the particle size of the kneaded product must be 100% by weight of 20 MM or less, and 10% of lO or less.
~100% by weight, 5 to 40-100% by weight, l M
5 to 50% by weight below M, 0.1% by weight, 10% below AM
Must be less than or equal to On the other hand, in the forming strip pt=, when the forming pressure is 1%Q or less, the bulk density of the formed object is small;
It does not develop high strength by steam treatment, and at 501G or higher, the amount of water added that can be molded is less than the plasticity limit of the 6-mixed body, does not develop high strength by steam treatment, and lacks mass productivity on an industrial scale. Therefore, in order for the molded body to develop high strength through steam treatment, the molding pressure must be between 1 and 501 G.

The main factors for curing conditions are curing temperature and curing time. The curing process allows the hydration reaction to proceed slowly, and the
The purpose is to have an appropriate strength that can withstand the water utilization reaction expansion during steam treatment of C, and to create a high-strength cured body by steam treatment. In other words, if the curing temperature is low or the curing time is short, the strength of the cured product after curing will be low, and the strength will be 65 to 90.
Due to the steam treatment at °C, many cracks occur and the strength of the cured product decreases. On the other hand, if the curing temperature is too high, cracks will occur during curing, and if the curing time is not long, the amount of thick crystals will increase, and the amount of oblique crystals produced by steam treatment will decrease. In both cases, the strength of the cured product decreases. Furthermore, if the relative humidity is lower than 80%, water evaporates and water utilization reactions do not proceed sufficiently. Therefore, in order to produce a high-strength cured product, K should be adjusted to room temperature to 60°C (preferably 85 to 60°C).
°C) and a relative humidity of 80% or higher for 5 to 25 hours. In addition, by increasing the curing temperature, the curing time for producing high-strength cured products can be significantly shortened.
This greatly simplifies the process for industrial large-scale production of cured products.

Steam treatment conditions are the main factors of treatment temperature and treatment time. Generally, when the steam treatment time is short or the steam treatment temperature is low, the hydrated hardened product is composed of a mixture of calcium monosulfoaluminate and ettringite and has low strength.
As the steam treatment time becomes longer or the steam treatment temperature increases, the amount of ettringite produced increases and the strength also increases. If steam treatment is carried out for a long period of time or if the steam treatment temperature is too high, ettringite will lack heat and bioactivity. The l strength of the body decreases.

+14 positive steam treatment conditions vary depending on the water reactivity of the combustion ash, etc. For flow H,',1 combustion ash, the steam treatment conditions are 65~
A high-strength cured product can be obtained by treating with normal pressure steam at a temperature of 90°C for 5 to 15 hours.

In addition, this research covers not only a cured product having a predetermined shape, but also
Granular form obtained by crushing 111)! The present invention also provides a method for producing the compound. That is, when manufacturing a granular hardened body by pulverization, it is not necessary to mold it into a specific shape in advance, making it suitable for mass production.

When crushing after steam treatment, use Impact Cratsunya.
A normal crushing liquid such as a show crusher can be applied. Regarding the crushing method, the crushing trowel and operating conditions should be selected so that the particle size distribution and particle shape are suitable for the purpose of the granular hardened product. It is desirable to revise it.

Example Examples and comparative examples will be briefly described.

The chemical composition and physical properties of the fluidized bed combustion ash in Examples and Comparative Examples are shown in Table 1, and the proportions of constituent compounds are shown in Table 2.

(Leaving space below) The method for testing the hardened body of fluid 14 combustion ash and water 14fl is shown. Plain specific surface 1 ratio measurement is carried out using Shimadzu Corporation's 1'I\i injection; till measuring device. 5S-1
I put the 00 type into practical use and used the air permeability method. γ&Note limit is measured based on T Engineering SA 1205 (Zfi property limit test 1 method of soil), and plastic limit i4 J Engineering SA 1
Measured based on 206 (Method for estimating the plasticity limit of soil).

For bending strength test 1, the test piece was 40 x 40 x 160 (
#Ura) was used, and the MKS improved universal strength testing machine manufactured by Marubishi Kagaku Isasakusho was used as a testing device. Trial II
The thrift method was based on the three-point bending method. For the compressive strength test, a 40x40x40 (arm) test piece was used as the test piece.
As the safety device VT, a universal testing machine (maximum load of 10 tons) manufactured by Instron was used. The test method was the constant deflection rate method.

For the crushing strength test, a 10 mm piece was used as the test piece, and a Honya-style hardness tester (maximum load 30 kg) was used as the test device.

In addition, at 11 o'clock CBR, the maximum dry density was 095 when it was divided into three layers in the vertical direction and compacted 92 times with J-K5A1210 (soil compaction test/horizontal method).
%, CBR after 4 days of water immersion, which corresponds to the degree of hardening,
This CBR is given by the following formula based on the large resistance of a penetrating rod with a diameter of 5 ca, according to J-K5A1211 (subgrade soil bearing capacity ratio method).

Load when penetration amount is 2.5 mm (k” x 100 (%
) CBR" 1370 (/Cg) Note that in the Examples and Comparative Examples, atmospheric pressure steam was used as the steam.

Example 1 46 parts by weight of water was added to 100 parts by weight of fluidized bed combustion ash, a stirring vessel was rotated at 3 Q rpm, and one stirring blade was
Knead for 1.5 minutes with a kneader rotating at 201
This kneaded material is made into granules with a content of 100% by weight or less, 80% by weight of 10% or less, 60% by weight of 5% or less, 6% by weight of 1% or less, and 0% by weight of 0.1mttr or less, and this kneaded product is heated at a pressure of 201G. After pressing and curing for 15 hours in a humid atmosphere at 50'C and a relative humidity of 80% or more,
After time treatment, a water-containing cured product was obtained. The characteristics of hydraulic hardening bodies are the third.
It was as shown in the table.

Comparative Example 1 Flow: 46 parts by weight of water was added to 41 parts of 100 parts by weight of Xa combustion ash, the stirring container was fixed, and the two surface stirring blades were set at 20 Orp.
Rotate in the opposite direction at 1100 rpm and knead for 2 minutes, 40 or less 100 ff1i 4%, 20 or less 8
0% by weight, 10: 6% by weight below smm, 5; uyt
Below 40% by weight, below 171m 10% by weight, 11%, Q, l
The same experiment as in Example 1 was carried out using a small amount of granules with a size of 1 m or less.

The characteristics of the water-containing hardened material were as shown in Table 8.

Comparative Example 2 40 parts by weight of water was added to 100 parts by weight of fluidized bed combustion ash, the stirring container was fixed, and the two stirring blades were set at 20 rpm and 11 rpm.
Knead for 3 minutes with a mixer that rotates in the opposite direction at 00 rpm, and mix for 20 minutes.
MIt or less 100% by weight, IQl 11ml or less 95% by weight, 5 or less 75% by weight, 1 or less 40% by weight, 0.1
The granules were made into 5% by weight granules, and the same beak as in Example 1 was carried out thereafter. The properties of the water-containing hardened material were as shown in Table 3.

Comparative Example 3 35 parts by weight of water was added to 100 parts of bamboo ash from fluidized bed combustion, a gate stirring vessel was fixed, and two stirring blades were set at 20 Orpm and 1
I in the opposite direction at 100 rp! l! Knead for 4 minutes with a kneading machine taught by II, 100% by weight of 20 or less, 100% by weight of 10 or less, 80% by weight of 5 or less, 45% by weight of 1 or less, Q,
The kneaded material is made into granules with a concentration of 5% by weight or less.10
Pressure molding was carried out at a pressure of 0SG, and thereafter the same experiment as in the example was conducted. The custom-made hydraulic hardening bodies were as shown in Table 3.

Comparative Example 4 A molded article produced in the same manner as in Example 1 was cured for 40 hours in a humid atmosphere at 50°C and a relative humidity of 80% or more.
A hydrated and cured product was obtained by treatment for 10 hours at 1 °C under normal pressure steam. The properties of the water-containing hardened material were as shown in Table 3.

(Left below) Example 2 The hardened material shown in Example 1 in Table 3 was crushed using a show crusher, and 20111 or less 100%, 1
01R11 or less 68% by weight, 5! 46% by weight below DI,
37% by weight below 1st order, 2.0% by weight below Q, l MM
A granular hardened gold body with a particle size distribution of . The properties of this granular cured product were as shown in Table 4.

As described in detail in Table 4, according to the present invention, fluidized bed combustion ash, which is an exhaust product during coal combustion, is kneaded with water that is greater than the plastic limit and less than the liquid limit, and is mixed with a predetermined particle size needle. ? After granulating it to 1i and low-pressure press molding, it is cured in a humid air at room temperature to 60°C and then subjected to normal pressure steam treatment to produce a hardened product with high strength and granular hardness obtained by pulverization. It is possible to easily produce Ihi bodies in a short time, and the present invention is applicable to the production of various building materials, structural materials, road materials, backfilling materials, etc. in the fields of civil engineering and construction by effectively utilizing fluidized bed combustion ash. It is extremely useful as a contributing technology.

Applicant: Kawasaki Heavy Industries, Ltd.

Claims (1)

[Scope of Claims] 1 Coal ash generated during fluidized bed combustion in a fluidized bed consisting of coal as a fuel and limestone as a desulfurization agent and spent desulfurization agent contain 60 to 85% by weight of coal ash.
, quicklime or/and slaked lime, so that the blending ratio is 10 to 25% by weight of lime and 5 to 25% by weight of gypsum.
and type II anhydrous gypsum, hemihydrate gypsum or/and dihydrate gypsum as needed to prepare a mixed powder,
In the method of adding water to this mixed powder, kneading it, and then curing it, add water that is more than the plastic limit of the mixed powder and less than the liquid limit, and knead it to reduce the particle size to 100 mm or less. Weight%, particle size 10mm or less 60-100% by weight
After kneading into a kneaded product having a particle size distribution of 40 to 100% by weight with a particle size of 5 mm or less, 5 to 50 weight% with a particle size of 1 mm or less, and 10 weight% or less with a particle size of 0.1 mm or less, 1 to 50 kg/cm
A method for producing a hardened product using fluidized bed combustion ash as a main raw material, characterized by pressure molding at a pressure of ^2G. 2. A method for producing a hardened body using fluidized bed combustion ash as a main raw material according to claim 1, wherein the cured body is pulverized into granular hardened bodies having a particle size of 40 mm or less.