JP6970374B2 - Coal ash molding and its manufacturing method - Google Patents

Description

The present invention relates to a coal ash molded product to be charged into a clinker cooler and a method for producing the same in the cement clinker manufacturing process.

Currently, a large amount of coal ash of about 10 million tons is generated annually from thermal power plants, and in order to reuse this as a resource, attempts have been made to use it as an admixture for concrete. However, due to the tightening of environmental regulations such as NOx emission regulations and the priority of power generation efficiency, pulverized coal tends not to be completely burned, and the amount of unburned carbon in the recovered coal ash is increasing. When coal ash with a large amount of unburned carbon is used as an admixture for concrete, unburned carbon interferes with the effects of AE agents and makes it difficult to introduce entrained air, and unburned carbon, which is a black substance, forms the surface of concrete. It causes problems such as being raised in the concrete and spoiling the appearance.

Therefore, instead of using an admixture for concrete, coal ash with a large amount of unburned carbon is put into a cement clinker immediately after production with a cooler directly under the kiln to burn and remove unburned carbon. There is known a method for treating coal ash in which the coal ash from which is removed is crushed together with clinker and mixed with cement (Patent Document 1).

In the treatment method in which coal ash is put into a cement clinker immediately after production to burn and remove unburned carbon, coal ash is used as a molded product so that the coal ash does not scatter. A treatment method in which the crushing strength and the drop strength of the coal ash molded product are set to a certain level or higher so as not to collapse has been proposed (Patent Document 2).

Japanese Unexamined Patent Publication No. 2005-104792 Japanese Patent No. 5991998

In the method of Patent Document 2, a coal ash molded product having a predetermined crushing strength and drop strength is used, but the water content of the molded product is not controlled. Specifically, in the method of Patent Document 2, a composition containing 2 to 35 parts by mass of water with respect to 100 parts by mass of a total amount of coal ash and a binder is formed, cured and dried to obtain a predetermined crushing strength and a predetermined crushing strength. Although the molded product has a drop strength, the water content of the molded product after curing and drying is not controlled.

Therefore, even if the coal ash molded product has a predetermined crushing strength and drop strength, when the water content is high, when the coal ash molded product is put into a cement clinker at a high temperature immediately after production, the molding is performed. Moisture contained in an object may rapidly expand, causing a steam explosion, and the molded article may explode and scatter. The ruptured and finely divided molded product easily reacts with the clinker, and the cement mineral composition in the clinker varies depending on the degree of the reaction, so that it becomes difficult to maintain the clinker quality constant.

In addition, since the finely divided molded product may be mixed with the secondary air introduced from the clinker cooler into the rotary kiln and the tertiary air introduced into the calciner, these air are circulated to the rotary kiln and the calciner. Then, there is a problem that the scattered matter of the molded product contained in the air is brought into the firing step and reacts with the clinker to change the mineral composition of the clinker.

Further, in Patent Document 2, the carbon content of the coal ash used is preferably 3% or more, more preferably 4 to 50%, further preferably 5 to 45%, and particularly preferably 6 to 40%. Coal ash with a content of 10% or more has a large amount of unburned carbon remaining in the method according to the patent, which may adversely affect the cement quality.

Further, Patent Document 2 describes a preferable range of shape and size and crush strength (or drop strength) of the molded product. However, when the wind speed in the clinker cooler is about 5 to 6 m / s, the density of the molded product is ^{less than 1.8 g / cm 3} and the volume is ^{less than 0.25 cm 3} , the molded product is secondary air and 3 These ranges described in Patent Document 2 may not always be preferable because they may be recovered in the next air.

Further, in Patent Document 2, the coal ash molded product is put into a high temperature region of a cement cooler to be mixed with a clinker and the carbon in the coal ash is burned. Since latent heat is not taken into consideration, it is difficult to reduce the carbon content of the molded product after burning unburned carbon to 1% or less, at least 2% or less, and a considerable amount of unburned carbon remains. Therefore, the problem of unburned carbon contained in coal ash cannot be sufficiently solved.

The present invention solves the above-mentioned problems in the conventional coal ash molded product, and the coal ash molded product does not easily collapse when it is put into a high temperature region of a cement cooler, and the unburned carbon contained in the coal ash is sufficient. To provide a coal ash formation to be burned and removed and a method for producing the same.

The present invention relates to a coal ash molded product and a method for producing the same, which have solved the above problems by the following configurations.
[1] It contains 90.0 to 99.6 parts by mass of coal ash having an unburned carbon content of 2.0 to 15.0 mass%, and contains an amount of a binder having a crushing strength of 5 N or more in a dry state, and is dried. The water content in the state is 1.5% by mass or less, the density is 1.8 g / cm ³ or more (excluding 1.8 g / cm ³ ), the volume is 0.25 cm ³ or more, and in the temperature range of 800 ° C or more of the clinker cooler. A coal ash molded product characterized in that the amount of unburned carbon is reduced to 1.0% or less by burning the unburned carbon.
[2] The coal ash molded product according to the above [1], wherein the amount of unburned carbon is reduced to 0.5% or less by burning unburned carbon in a temperature range of 800 ° C. or higher in a clinker cooler.
[3] Coal ash with an unburned carbon content of 2.0 to 15.0% by mass, 90.0 to 99.6 parts by mass, a binder having a crushing strength of 5 N or more in a dry state, and coal ash and a binder. After mixing 15 to 50 parts by mass of water with 100 parts by mass of the total amount to form a mixture, crush strength of 5 N or more, density of 1.8 g / cm ³ or more (excluding 1.8 g / cm ³ ), By curing and drying so that the volume is 0.25 cm ³ or more and the water content is 1.5% by mass or less , the unburned carbon of the coal ash molded product is burned by the clinker cooler in the temperature range of 800 ° C. or higher. A method for producing a coal ash molded product in which the amount of unburned carbon is reduced to 1.0% or less.
[4] In the production method of the above [3], the amount of unburned carbon in the coal ash molded product is reduced to 0.5% or less by burning the clinker cooler in a temperature range of 800 ° C. or higher. A method for manufacturing a coal ash molded product.

The coal ash molded product of the present invention is put into a clinker cooler in which the cement clinker immediately after production discharged from the rotary kiln is transported, and the unburned carbon contained in the coal ash is transported in the clinker cooler due to the high temperature of the cement clinker. This is for using coal ash from which unburned carbon has been removed by burning as a cement mixture.

Since the coal ash molded product of the present invention has a crushing strength of 5 N or more, it does not easily collapse when a cement clinker is added, and since the water content in a dry state is 1.5% by mass or less, it can be placed in a high temperature range of 800 ° C. or higher. When it is charged, it does not burst due to rapid water expansion, and the molded product is difficult to be pulverized.

The coal ash molded product of the present invention has a drying density of 1.8 g / cm ³ or more (excluding 1.8 g / cm ³ ) and a volume of 0.25 cm ³ or more, and does not scatter at the wind speed in a general clinker cooler. It is difficult to be taken in by the clinker cooler secondary air supplied to the roller Lee kiln and the tertiary air supplied to the calcining furnace, and is not circulated in the cement clinker firing process. Therefore, there is almost no change in the clinker mineral composition due to the reaction between the coal ash and the cement clinker, and the clinker mineral composition can be stably maintained.

Further, in the coal ash molded product of the present invention, coal ash having an unburned carbon content of 2.0 to 15.0 mass% can be used, and a large amount of coal ash having a large unburned carbon content, which is not suitable as a cement mixture, is used. Can be processed efficiently.

Further, the coal ash molded product of the present invention is produced by adding a binder in an amount such that the crushing strength in the dry state is 5 N or more, curing and drying so that the water content in the dry state is 1.5% by mass or less. It can be easily carried out because it does not use special chemicals or manufacturing equipment.

Hereinafter, the present invention will be specifically described.
[Coal ash molded product]
The coal ash molded product of the present invention contains 90.0 to 99.6 parts by mass of coal ash having an unburned carbon content of 2.0 to 15.0 mass%, and has an amount of crushing strength of 5 N or more in a dry state. It contains a binder, has a dry water content of 1.5% by mass or less, a density of 1.8 g / cm ³ or more (excluding 1.8 g / cm ³ ), a volume of 0.25 cm ³ or more, and is 800 of a clinker cooler. It is a coal ash molded product characterized in that the amount of unburned carbon is reduced to 1.0% or less by burning unburned carbon in a temperature range of ° C. or higher. Preferably, it is a coal ash molded product in which the amount of unburned carbon is reduced to 0.5% or less.

Coal ash having an unburned carbon content of 2.0 to 15.0% by mass is used for the coal ash molded product of the present invention. Since coal ash having an unburned carbon content of less than 2.0% by mass can be used as it is as a cement mixture, there is little need to use it in the coal ash molded product of the present invention. On the other hand, when the amount of unburned carbon in coal ash exceeds 15.0% by mass, the amount of residual unburned carbon increases when the unburned carbon is burned by being put into the temperature range of 800 ° C. or higher of the clinker cooler. , It becomes difficult to reduce the amount of unburned carbon to 1.0% or less. If the amount of residual unburned carbon after combustion is large, most of the AE agent used for concrete is adsorbed on the unburned carbon, which makes it difficult to control the amount of air in the concrete. In addition, if the amount of unburned oxygen is large, unburned carbon, which is a black substance, emerges on the concrete surface, causing problems such as spoiling the appearance.

The specific surface area (brain) of coal ash is ^{preferably 3000 cm 2} / g or more. For coal ash having a specific surface area of 3000 cm ² / g or less, if the amount of binder is small, the crushing strength of the molded product after drying may not be secured at 5 N or more.

The coal ash molded product of the present invention contains 90.0 to 99.6 parts by mass of the above unburned carbon content of coal ash. If the content of coal ash is less than 90 parts by mass, the activity index of the coal ash molded product becomes low, and the effect as the coal ash molded product becomes insufficient. When the content of coal ash exceeds 99.6 parts by mass, the content of the binder becomes relatively small, and the crushing strength in a dry state cannot be maintained at 5 N or more.

The coal ash molded product of the present invention contains an amount of a binder having a crushing strength of 5 N or more in a dry state. If the crushing strength in the dry state is less than 5N, it is not preferable because it collapses due to the impact at the time of dropping when it is put into the cement clinker. Generally, the crushing strength is preferably in the range of 5N to 250N. In order for the crushing strength to exceed 250 N, a large amount of binder is required and the molding efficiency is lowered, which is not preferable.

As the binder, either an organic binder or an inorganic binder can be used. Further, an organic binder and an inorganic binder can be mixed and used. In order for the molded product to have a crushing strength of 5 to 250 N in a dry state, the content of a general organic binder is preferably 0.4 to 5 parts by mass, and the content of a general inorganic binder is 5 to 10 parts by mass. Is preferable.

As the organic binder, starch, solid paraffin, polyvinyl alcohol, cellulose derivative, styrene butadiene rubber, natural rubber, guagam derivative, vinyl acetate, ethylene vinyl acetate resin, acrylic resin and the like can be used.
As the inorganic binder, ordinary Portland cement, early-strength Portland, moderate heat Portland cement, low heat cement, blast furnace cement, fly ash cement, alumina cement, silica fume, bentonite powder, clay powder and the like can be used.

Further, by adding an alkaline stimulant that brings out the pozzolanic activity of coal ash alone or in combination with the above binder, the crushing strength of the coal ash molded product can be increased. Examples of the alkaline stimulant include sodium carbonate, potassium carbonate, lithium carbonate (sodium carbonate, potassium carbonate, lithium carbonate), oxycarboxylate (sodium citrate, lithium citrate), sodium aluminate, and the like.

The coal ash molded product of the present invention has a water content of 1.5% by mass or less in a dry state. When the water content in the dry state exceeds 1.5% by mass, when it is put into the high temperature range of 800 ° C or higher of the clinker cooler, steam explosion occurs due to the rapid expansion of the water content, and it collapses when the crushing strength is about 5N. And scatter. If the water content in the dry state is 1.5% by mass or less, such steam explosion is unlikely to occur. When the coal ash molded product collapses and scatters, the unburned carbon is not sufficiently burned and the scattered coal ash powder is brought into the secondary or tertiary air of the clinker cooler and introduced into the clinker firing process. Since it circulates in the cooler, it becomes difficult to reduce the amount of unburned carbon in the cooler recovered material to 1.0% or less. Cement produced by clinker containing coal ash with a large amount of unburned carbon is not preferable because a black substance will be exposed on the surface of the cement molded product.

The coal ash molded product of the present invention has a dry density of 1.8 g / cm ³ or more (excluding 1.8 g / cm ³ ) and a volume of 0.25 cm ³ or more. Dry density 1.8 g / cm ³ less than the volume is less than 0.25 cm ³ in particulate is easily scattered to the secondary without air clinker cooler by velocity of the tertiary air, scattered coal ash secondary air and tertiary air When brought into the air and circulated in the firing process, it may react with cement clinker to cause compositional changes in clinker minerals.

〔Production method〕
The coal ash molded product of the present invention has 99.0 to 99.6 parts by mass of coal ash having an unburned carbon content of 2.0 to 15.0 mass% and a binder having an amount of crushing strength of 5 N or more in a dry state. After mixing 15 to 50 parts by mass of water with 100 parts by mass of the total amount of coal ash and the binder and forming the mixture, the crushing strength is 5 N or more and the drying density is 1.8 g / cm ³ or more (1. It can be cured and dried so as to have a volume of 0.25 cm ³ or more and a water content of 1.5% by mass or less ( excluding 8 g / cm ^3).

The amount of water added to the mixture of the coal ash and the binder is preferably 15 to 50 parts by mass with respect to 100 parts by mass of the total amount of the coal ash and the binder. If the amount of water added to the mixture is less than 15 parts by mass, kneading for molding cannot be performed, and if it exceeds 50 parts by mass, there is a problem that the kneaded material adheres to the molding apparatus, and the water content after drying is 1. It is not preferable because a large amount of heat energy is required to reduce the content to .5% by mass or less.

By using an alkaline stimulant that brings out the pozzolanic activity of coal ash alone or in combination with the above binder, the crushing strength of the coal ash molded product can be increased. Examples of the alkaline stimulant include sodium carbonate, potassium carbonate, lithium carbonate (sodium carbonate, potassium carbonate, lithium carbonate), oxycarboxylate (sodium citrate, lithium citrate), sodium aluminate and the like. The crushing strength can be increased by adding 0.1 to 1.0 parts by mass of one or more of these to 100 parts by mass of coal ash.

Various molding means such as extrusion molding and roll press can be used for molding the kneaded product. Molding also includes granulation. As the granulation means, various granulation means such as a bread pelletizer can be used. The molding means and the granulation means are not limited.

After molding, the present invention is cured and dried so that the drying density is 1.8 g / cm ³ or more (excluding 1.8 g / cm ³ ), the volume is 0.25 cm ³ or more, and the water content is 1.5% by mass or less. Manufactures coal ash moldings. For example, it is preferable to use a continuous dryer or the like in which the molded product is dispersed by vibration and hot air of 100 ° C. to 300 ° C. is blown to dry the molded product.

〔The invention's effect〕
Since the coal ash molded product of the present invention has a low water content, it is unlikely to collapse due to rapid expansion of water content when it is put into a high temperature region of 800 ° C. or higher. Therefore, even if the coal ash is put on the clinker immediately after production which is conveyed in the clinker cooler, the unburned carbon is burned without scattering the coal ash, and the unburned carbon is reduced to 1.0% or less. Preferably, the amount of unburned carbon is reduced to 0.5% or less. Therefore, the amount of unburned carbon incorporated into the cement clinker is significantly small, and the coal ash from which carbon has been removed by combustion can be satisfactorily used as a cement mixture.

Further, since the coal ash molded product of the present invention has a drying density of 1.8 g / cm ³ or more (excluding 1.8 g / cm ³ ) and a volume of 0.25 cm ³ or more, the wind speed in a general clinker cooler Since it does not scatter, coal ash is not brought into the firing process, and the cement clinker and coal ash do not react with each other, so that the mineral composition of the clinker does not fluctuate and the quality of the clinker can be maintained satisfactorily.

Hereinafter, examples of the present invention will be shown together with comparative examples.
For the molded product, the water content in the dry state was measured based on JIS standard JIS A 6201 "fly ash for concrete".
The crushing strength was measured by using an Instron-type universal testing machine after preparing a cylindrical specimen having the same composition as the molded product and having a diameter of 5 mm and a height of 10 mm by extrusion molding, and after predetermined curing and drying.
The density was measured based on JIS standard JIS R 5201 "Physical test method for cement".
The volume of the molded product was calculated by dividing the amount of the molded substance by the density.
The following ABC was used as the coal ash.
Coal ash A (unburned carbon content 14.2% by mass, brain specific surface area 3500 cm ² / g),
Coal ash B (unburned carbon content 4.5% by mass, brain specific surface area 3610 cm ² / g)
Coal ash C (unburned carbon content 17.4% by mass, brain specific surface area 3580 cm ² / g)
Starch (Matsutani Chemical Industry Co., Ltd.) was used as the organic binder, and clay powder (Bentonite manufactured by Kunimine Industry Co., Ltd.) was used as the inorganic binder. Moreover, sodium carbonate (reagent first grade) and sodium aluminate were used as an alkali stimulant. Tap water was used as the kneading water.

[Example A: Preparation of coal ash molded product]
Coal ash A, binder (starch, clay powder), alkaline stimulant (sodium carbonate), and water were kneaded at a ratio shown in Table 1 at 500 rpm for 1 minute using a Henshell mixer (model FM20B type). Was molded into dimensions having a diameter of 6 mm and a height of 10 mm by an extrusion molding method. This was cured under the conditions of 40 ° C. and 80% humidity for 24 hours, and then dried by a fluidized bed dryer (model 10F type) at 110 ° C. and an air volume of 5 m ³ / min for 60 minutes to produce a molded product. Table 1 shows the density, crush strength, and water content of this molded product.

As shown in Table 1, when the amount of the binder was 0.4 to 10% by mass, the crushing strength of the coal ash molded product was 5 N or more. When the water content was 60% or more, the density of the coal ash molded product was ^{less than 1.8 cm 3} / g, and the water content after drying was 2.5% or more.

[Example B: Moisture content and disintegration of coal ash molding]
Coal ash A, binder (starch), and water were mixed in the same proportions as in Example 2 of Table 1 and kneaded at 500 rpm for 1 minute using a Henschel mixer (model FM20B type), and this kneaded product was extruded and molded. By the method, it was molded into dimensions having a diameter of 6 mm and a height of 12 mm. After curing this for 24 hours under the conditions of 40 ° C. and 80% humidity, 0 minutes, 10 minutes, 20 minutes, 30 minutes under the conditions of ^{110 ° C. and air volume of 5 m 3 / min in a fluidized bed dryer (model 10F type).} The molded product was produced by drying for 40 minutes, 50 minutes, and 60 minutes. This molded product was placed in a test furnace, air at 800 ° C. was introduced at a wind speed of 6 m / s, and the mixture was calcined for 30 minutes to examine the degree of disintegration. In addition, the coal ash molded product is recovered from the air in the furnace for up to 3 minutes immediately after being put into the test furnace, and the recovered air is passed through a white filter. Those with a small amount of coal ash were considered to have a large amount of coal ash, and those with a filter that turned dark gray to black were considered to have a large amount of coal ash. Table 2 shows the water content, crushing strength, presence or absence of high temperature collapse, and the amount of coal ash in the recovered air of this molded product.

As shown in Table 2, when the molded product is fired at a high temperature of 800 ° C. for 30 minutes, all the molded products having a water content of 1.9% or more disintegrate and scatter, and some molded products having a water content of 1.6% also disintegrate. It collapses slightly. On the other hand, a molded product having a water content of 1.5% or less does not disintegrate even under such high-temperature firing and does not scatter, so that coal ash does not mix in the recovered air.

[Example C]
The blending amounts of coal ash A, binder (starch, clay powder), alkaline stimulant (sodium carbonate), and water are the same as in Example 2, Example 3, Example 7, Comparative Example 1, and Comparative Example 2 in Table 1, respectively. Regarding the molded product, the blended raw materials were kneaded at 500 rpm for 1 minute using a starch mixer (model FM20B type), and this kneaded product was molded into the following three types (a, b, and c) by the extrusion molding method. bottom.
(B) Diameter 10 mm, height 15 mm, volume about 1.2 cm ³ ,
(B) Diameter 6 mm, height 10 mm, volume about 0.28 cm ³ ,
(C) Diameter 5 mm, height 5 mm, volume approx. 0.1 cm ³
These were cured under the conditions of 40 ° C. and 80% humidity for 24 hours, and then dried in a fluidized bed dryer (model 10F type) at 110 ° C. and an air volume of 5 m ³ / min for 60 minutes to produce a molded product. In Comparative Example 2, the water content could not be reduced to 1.5% or less in the drying time of 60 minutes, so the drying time was extended to 90 minutes. Further, this molded product was placed in a test furnace, air at 800 ° C. was introduced at a wind speed of 6 m / s, and the product was fired for 30 minutes to examine the degree of decay and the amount of unburned carbon after firing. In addition, the air in the furnace was recovered from immediately after the coal ash molded product was put into the test furnace for up to 3 minutes, and the amount of coal ash contained in the recovered air was investigated. The results are shown in Table 3.

As shown in Table 3, the molded product of Example 2, 3 and 7, the volume 0.25 cm ³ or more, both the density 2.0 g / cm ³ or more samples less coal ash content in the recovered air, air It turns out that it is difficult to be taken in. On the other hand, in each sample having a volume of 0.1 cm ³ of the molded product, the amount of coal ash in the recovered air is measured even though the amount is small. 0.25 cm ³ or more is preferable. In Comparative Example 1, since the crushing strength is 3N, it easily collapses and the amount of coal ash in the recovered air is large. Also, Comparative Example 2 is the density of 1.7 g / cm ³ of coal ash moldings, coal ash amount of recovery in the air for less than 1.8 g / cm ³ is slightly more or greater. In Table 3, the amount of coal ash in the recovered air was slightly large because the filter turned dark gray. Others are the same as the judgment criteria in Table 2.

[Example D]
Coal ash A, coal ash B, coal ash C, binder (starch), alkaline stimulant (sodium carbonate), and water are mixed in the proportions shown in Table 4, and 1 at 500 rpm using a Henshell mixer (model FM20B type). This kneaded product, which had been kneaded for a minute, was formed into dimensions having a diameter of 6 mm and a height of 10 mm by an extrusion molding method. This was cured for 24 hours under the conditions of 40 ° C. and 80% humidity, and then dried in a fluidized bed dryer (model 10F type) at 110 ° C. and an air volume of 5 m ³ / min for 60 minutes to produce a molded product. Further, this molded product was placed in a test furnace, air at 800 ° C. was introduced at a wind speed of 6 m / s, and the amount of unburned carbon after firing for 20 minutes, 30 minutes, and 60 minutes was examined. The results are shown in Table 4. The raw material formulations of Examples 2 and 3 in Table 4 are the same as those of Examples 2 and 3 in Table 1.

As shown in Table 4, in Examples 2, 3, 3 and 10 using coal ash A and B having an unburned carbon content of 15% or less, the unburned carbon content is reduced to 1% or less. Comparative Example 4 using coal ash C having an unburned carbon content of 17.4% is preferable because the unburned carbon content after firing is 1.2% or more and the residual unburned carbon content after combustion is large. No.

〔実施例Ｅ〕

[Example E]

Coal ash A, coal ash B, coal ash C, binder (starch), alkaline stimulant (sodium carbonate), and water are mixed in the proportions shown in Table 5, and 1 at 500 rpm using a Henshell mixer (model FM20B type). This kneaded product, which had been kneaded for a minute, was formed into dimensions having a diameter of 6 mm and a height of 10 mm by an extrusion molding method. This was cured for 24 hours under the conditions of 40 ° C. and 80% humidity, and then dried in a fluidized bed dryer (model 10F type) at 110 ° C. and an air volume of 5 m ³ / min for 60 minutes to produce a molded product. Further, 1000 g of ordinary Portland cement clinker was heated in a heating furnace at 800 ° C., and 50 g of the above coal ash molded product (5% by mass with respect to 100% by mass of cement clinker) was sprayed thereto. After firing for 20 minutes, 30 minutes, and 60 minutes in a test furnace, 2% of dihydrate gypsum was added and ^{pulverized until the brain specific surface area became 3300 cm 2} / g, and ordinary Portland cement was prepared.
For the trial-made cement, mortar is kneaded with 450 g of cement, 1350 g of standard sand, and 50% of water-cement ratio according to JIS standard (JIS R 5201 "Physical test method of cement"), and a black substance that emerges on the surface of the obtained mortar. I checked for the presence of.

As shown in Table 5, in Examples 2, Example 3, and Example 10 using coal ash A and B having an unburned carbon content of 15% or less, no floating of a black substance was observed. On the other hand, Comparative Example 4 using coal ash C is not preferable because floating of a black substance is observed.

Claims (4)

It contains 90.0 to 99.6 parts by mass of coal ash with an unburned carbon content of 2.0 to 15.0 mass%, and contains an amount of binder that makes the crushing strength in the dry state 5 N or more, and contains the dry state. The amount of water is 1.5% by mass or less, the density is 1.8 g / cm ³ or more (excluding 1.8 g / cm ³ ), the volume is 0.25 cm ³ or more, and the clinker cooler is unburned in the temperature range of 800 ° C or more. A coal ash molded product characterized in that the amount of unburned carbon is reduced to 1.0% or less by burning carbon. The coal ash molded product according to claim 1, wherein the amount of unburned carbon is reduced to 0.5% or less by burning unburned carbon in a temperature range of 800 ° C. or higher in a clinker cooler. 90.0 to 99.6 parts by mass of coal ash with an unburned carbon content of 2.0 to 15.0 mass%, a binder with an amount of crushing strength of 5 N or more in a dry state, and a total amount of coal ash and a binder of 100. After mixing 15 to 50 parts by mass of water with respect to the mass part to form a mixture, the crushing strength is 5 N or more, the density is 1.8 g / cm ³ or more (excluding 1.8 g / cm ³ ), and the volume is 0. By curing and drying so that the content is 25 cm ³ or more and the water content is 1.5% by mass or less , the unburned carbon of the coal ash molded product is converted to unburned carbon by burning in the temperature range of 800 ° C or higher in the clinker cooler. A method for producing a coal ash molded product whose amount is reduced to 1.0% or less. The production method according to claim 3, wherein the amount of unburned carbon in the coal ash molded product is reduced to 0.5% or less by combustion of the clinker cooler in a temperature range of 800 ° C. or higher. Manufacturing method.