KR101200849B1 - Manufacturing methods of kaolin brick and the kaolin brick thereof - Google Patents

Abstract

PURPOSE: A fuel saving type kaolin brick manufacturing method using fly ash and a kaolin brick are provided to optimize physical properties of bricks, high-pressure molding of bricks, drying contraction, and conditions for heating plasticity process. CONSTITUTION: A fuel saving type kaolin brick manufacturing method using fly ash comprises the following steps: mixing 40 wt% of kaolin terra alba, 20 wt% of kaolin clay and 40 wt% of fly ash; molding the mixed soil mix in a vacuum condition at the high pressure (200 horse power); and drying the molded brick and heating and sintering the dried brick in a kiln. The fly ash is anthracite coal ashes having large amount of unburned residual carbon. The heating and sintering in the third step is processed at 1130 deg. Celsius of 2.5 hours. [Reference numerals] (AA) Increasing mixing ratio of fly ash; (BB) Cracking; (CC) Cracking; (DD) Cracking

Description

Manufacturing method of fuel-saving kaolin brick using fly ash and its kaolin brick {Manufacturing methods of kaolin brick and the kaolin brick

The present invention relates to a kaolin brick manufacturing method and kaolin bricks prepared by adding fly ash to kaolin clay and kaolin clay, and more specifically, to the properties of the fly ash (fly ash) without the addition of a plasticizer The mixing ratio provides optimally the conditions of high pressure forming, drying shrinkage, heating and firing process of the brick and the physical properties of the brick (absorption rate, compressive strength, etc.), but the self-heating by unburned residual carbon of the fly ash, It is used as a firing fuel because it lowers the firing temperature and reduces the firing time when firing with tunnel type kiln. The present invention relates to a fuel-saving kaolin brick manufacturing method using fly ash, which is excellent in economical and eco-friendly effects, and also suppresses black core generation, which is a disadvantage of conventional fly ash-added products, and has excellent commerciality of bricks. .

In general, fired bricks, which are mainly used in buildings, use clay, especially kaolin, in recent years.

Such kaolin uses natural minerals buried in Korea, but the development of natural resources has been suppressed due to the depletion of mineral resources and environmental protection, and it is increasingly difficult to secure minerals, which are the raw materials of plastic bricks. The development of materials that can be urgently urgent.

In order to solve this problem, various methods for manufacturing industrial wastes such as coal ash and waste gypsum are mixed with natural minerals such as kaolin.

In particular, the coal ash refers to a material remaining after burning coal in a coal fuel power plant.

These ashes are classified into button ash and fly ash according to the place where they are collected after combustion. The button ash is attached to the furnace wall, superheater, reheater, etc. and falls to the bottom of the boiler by its own weight. Is about 1 ~ 2.5mm or more, and the fly ash refers to the ashes gathered in the hopper under the cutter or air preheater and the ashes gathered in the hopper under the dust collector. The particle size of the ash collected by the electrostatic precipitator and collected in the lower hopper depends on the type of coal and combustion conditions, but it is usually 10 ~ 30㎛ and most of the ash is recycled.

Such coal ash is being reused for various purposes, and recently, it is manufactured by adding it to replace natural minerals such as kaolin.

For example, in Patent Application No. 2003-31727, coal ash (fly ash) is added to prepare a porous lightweight clay brick, and Patent Application No. 2010-79370 uses a binder mixed to solve the plasticity problem of coal ash. In the patent application No. 2003-74264, a light brick is manufactured by mixing purified sludge and coal ash with kaolin and clay, and in Patent No. 2004-9848, a plasticizer is mixed with coal ash with kaolin to make a high strength brick. It was prepared.

In other words, the conventional coal-based brick simply uses a plasticizer as a substitute for saving natural minerals, so plasticizers cannot be used. And the physical properties (absorption rate, compressive strength, etc.) of the brick was not optimally considered, there was a problem that the quality of the product falls.

Above all, due to self-heating due to unburned residual carbon contained in the coal ash, it is not possible to consider a part that can reduce fuel use by reducing the firing temperature and reducing the firing time.

In addition, the conventional brick using the coal ash has a problem in that the commerciality of the brick is lowered because it does not solve the problem of black core due to the coal circuit.

The present invention has been invented to solve the problems of the prior art as described above, while producing a kaolin brick by adding fly ash to kaolin clay and kaolin clay, fly ash without the addition of a plasticizer The purpose is to provide optimum conditions for the high pressure molding of bricks, dry shrinkage, heating and firing process and physical properties (absorption rate, compressive strength, etc.) of bricks.

In particular, the firing temperature is lowered by self-heating due to unburned residual carbon of the fly ash, and it is used as a sintering fuel because it passes the non-sintering section while reducing the firing time when firing in a tunnel kiln. It is an object to provide an excellent commercial property of bricks by reducing the BC 油, economical and environmentally friendly effect, and also suppress the generation of black core, which is a disadvantage of the conventional fly ash added product.

The present invention adopts an anthracite coal ash containing more unburned residual carbon than coal bituminous coal ash in kaolin clay, kaolin clay, and fly ash, and mixing them in a blending ratio of 40% by weight, 20% by weight, and 40% by weight, respectively. And brick forming process of molding the mixed soil mixed in the mixing process under a high pressure (200 hp) in a vacuum state, drying process of drying the molded brick, and heating and baking the dried brick in a tunnel-type kiln, wherein the brick A fuel-saving kaolin brick manufacturing method manufactured by a heating firing process of heating and firing at 1130 ° C. for 2.5 hours by self-heating of unburned residual carbon of fly ash added to the ash;

Kaolin brick adopts anthracite coal ash, which contains more unburned residual carbon than bituminous coal coal ash among kaolin clay, kaolin clay and fly ash, and mixes the mixed soil in the mixing ratio of 40% by weight, 20% by weight and 40% by weight, respectively. After high-pressure molding into a shape, and drying and firing treatment, the unburned residual carbon of the fly ash is self-heating in the firing process to save fuel produced by heating and firing in a tunnel-type kiln at a firing temperature of 1130 ° C. and a firing time of 2.5 hours. It is characterized by providing a kaolin brick.

The present invention is to prepare a kaolin brick by adding fly ash to kaolin clay and kaolin clay, 40 wt%, 20 wt% of fly ash and kaolin clay, kaolin clay and fly ash without the addition of plasticizer %, 40% by weight of the mixing ratio of the high pressure molding of the brick, dry shrinkage, heating and calcining process conditions and the optimum physical properties of the brick (absorption rate, compressive strength, etc.), as well as in particular the unburned residual of the fly ash It is used as a sintering fuel because it lowers the sintering temperature of about 60 ℃ by the self-heating by carbon and reduces the sintering time when firing with tunnel type kiln and passes the non-sintering section. It is economical and eco-friendly because it reduces the BC 효과, and has the effect of providing excellent commercial property of the brick by suppressing the generation of black core which is a disadvantage of the conventional fly ash addition products.

1 is a compression molding test photograph of the brick of the present invention and a conventional brick product.
2 shows a tunnel burner.
Figure 3 is a diagram showing the firing temperature of the brick required to have a constant absorption rate as the amount of coal ash contained in the brick increases.
4 and 5 are diagrams showing the compressive strength indicating the load the brick can bear and the bending strength resisting the bending.
6 is a diagram showing the volume specific gravity according to the content of coal ash.
Figure 7 shows the compressive strength according to the firing temperature of the brick of the present invention.

First, the fuel-saving kaolin brick manufacturing method using the fly ash of the present invention will be described.

The present invention is to produce a kaolin brick through a high pressure molding of a mixture of a mixture of kaolin clay, kaolin clay and fly ash in the form of a brick, and then dried and calcined.

That is, the kaolin clay, kaolin clay and fly ash (fly ash) of the anthracite coal ash containing more unburned residual carbon than the coal ash, and the mixing process of mixing at a blending ratio of 40% by weight, 20% by weight, and 40% by weight, respectively; ,

A brick forming process of molding the mixed soil mixed in the mixing process under high pressure (200 hp) in a vacuum state;

Drying process of drying the molded bricks and heating and baking the dried bricks in a tunnel-type kiln, heat firing at 1130 ℃ for 2.5 hours by self-heating of unburned residual carbon of the fly ash (fly ash) added to the bricks It is prepared by a heat firing process.

In this case, the kaolin brick of the present invention is an anthracite coal ash (average particle diameter) containing more unburned residual carbon than fly ash (average particle diameter 17㎛, unburned carbon content 3-6%) of fly ash added to the mixed soil This 27㎛, the amount of unburned carbon (10-25%) is added, the heat saving efficiency by self-heating during the heating and baking process is more excellent.

Furthermore, the kaolin brick of the present invention is manufactured by mixing fly ash added to the blended soil at an optimum mixing ratio of 40% by weight, so that the conditions of compression molding, drying shrinkage, and heating and firing process, and physically prepared kaolin brick It will provide optimal properties (absorption rate, compressive strength, etc.).

This can be confirmed in more detail by the test for each manufacturing process below.

(1) compression molding test

Anthracite coal ash containing more unburned residual carbon than bituminous coal ash in kaolin clay, kaolin clay and fly ash, mixed with 40% by weight, 20% by weight and 40% by weight, respectively, and 35% by weight. , 15% by weight, 50% by weight of the blended soil was mixed at a high pressure (200 horsepower) in a vacuum state, respectively.

Since the fly ash (plasticity) is less plasticity, it is difficult to mold the brick when the content is high, and this is to confirm the problem because it causes the occurrence of cracking or brittleness of the brick.

As a result of the compression molding test, as shown in FIG. 1, cracks did not occur in a product in which 40% by weight of fly ash was mixed (left), but a product in which 50% by weight of fly ash was mixed (left). In, it was confirmed that cracks started to occur.

Therefore, the optimum mixing ratio of fly ash of the blended soil in the compression molding process was confirmed to 40% by weight.

(2) dry shrink test

Kaolin clay, kaolin clay and fly ash are selected from anthracite coal ash containing more unburned residual carbon than bituminous coal ash, and mixed at a blending ratio of 40% by weight, 20% by weight and 40% by weight, respectively, and the fly ash. A dry shrinkage test was performed to automatically dry bricks, which were high-pressure-molded bricks at an average temperature of 80 ° C. for 72 hours, by mixing the mixture of fly ash at 20 wt%, 30 wt% and 50 wt%, respectively, for 72 hours. As a result, it was not possible to confirm all of the cracks due to dry shrinkage imbalance due to the mixing ratio of the fly ash.

Therefore, the fly ash mixing ratio of the blended soil in the dry shrinkage process was found to have no effect.

(3) heating firing test

As a result of the tests of (1) and (2), 40% by weight of the fly ash mixing ratio of the mixed soil was found to be the optimum mixing ratio.

The optimum heating predetermined conditions (heating temperature, heating time) of the kaolin brick manufactured by the above-mentioned compounded soil are confirmed, and it is used as baking fuel In order to reduce BC 油, heating and firing conditions were tested under various conditions.

First, the brick sample (A) prepared by the blended clay mixed with 70% by weight and 30% by weight of the conventional kaolin clay and kaolin clay and the brick sample (B) prepared by the mixed soil mixed by the mixing ratio of the present invention, respectively. As a result of eight test results under various temperature conditions, the physical properties (absorption rate, compressive strength) of the samples were confirmed as shown in Table 1 below.

Sample Number One 2 3 4 5 6 7 8 Firing temperature 1050 ℃ 1070 ℃ 1090 ℃ 1110 ℃ 1130 ℃ 1150 DEG C 1170 ℃ 1190 ℃ A Absorption rate
(%) 15.5 14.2 13.5 12.1 11.3 10.6 9.5 8.2 Compressive strength
N / mm2 20 21 21 23 25 29 31 33 In volume ratio
g / cm³ 2.27 2.26 2.26 2.26 2.25 2.25 2.24 2.11 B Absorption rate
(%) 13.2 12.2 10.5 9.5 8.2 8.3 8.2 8.2 Compressive strength
N / mm2 22 23 26 28 33 35 38 40 In volume ratio
g / cm³ 1.91 1.89 1.87 1.88 1.86 1.86 1.86 1.86

That is, as a result of confirming the physical properties according to the temperature conditions, the physical properties (absorption rate and compressive strength) of 1190 ° C by the A brick sample prepared by the conventional compounding ratio and 1130 ° C by the B brick sample prepared by the compounding ratio of the present invention. Since the physical properties (absorption rate and compressive strength) are the same, it was confirmed that the B brick sample produced by the blending ratio of the present invention can be heat-fired at a temperature lower than about 60 ° C. compared to the A brick sample prepared by the conventional blending ratio.

In addition, the conventional brick (A brick sample) and the brick of the present invention (B brick sample) for one month to confirm the optimum firing holding time of the brick prepared by the conventional blending ratio and the brick prepared by the blending ratio of the present invention and the The calorific value of the process of heating and calcining in the same tunnel type kiln (preparing the burners from No. 1 to No. 11) was compared as shown in Table 2.

division Monthly production
(every) Monthly fuel consumption (L) Fly Ash Content (%) Brick weight
(kg) Output per kg of fuel (sheets) Fuel usage per ton of brick
(kg / ton) (Wf) Required calorific value (kcal) (Q) Savings rate A brick
sample 2,100,000 183,075 0 1.6 11.5 54.5 539,550 - B brick
sample 2,300,000 95,050 40 1.4 24.2 29.5 292,050 45.9

The required heat generation amount of the conventional brick (A brick sample),

Q1 = Wf × HL

539,550kcal = 54.5kg / brick × 9,900kcal / kg

Wf: 54.5kg / Brick Ton

HL: 9,900 kcal / kg (BC 油 calorific value)

That is, the firing conditions of the conventional brick (A brick sample) was a firing temperature: 1170 ℃, firing time: 5.5 hours, the heat of combustion: 539,550 kcal,

Saving heat amount of the brick (B brick sample) of the present invention,

Combustion rate of unburned carbon Q3 = (c1 × c2) × HL

220,800kcal = (400kg / brick ton × 12%) × 4,600kcal / kg

Weight ratio: 60% kaolin, fly ash 40% by weight

c1: 400kg / brick ton

c2: unburned carbon content 12%

HL: Low calorific value 4,600kcal / kg of unburned carbon

That is, the firing time reduction rate of the brick of the present invention (B brick sample) was reduced by 44.5% (5.5 hours to 2.5 hours in total) by reducing the heating temperature from 1170 ° C to 1130 ° C (3.5%) and reducing the heat from 539,550 kcal to 220,800 kcal (41%). ) Was confirmed.

Based on these calculations, the burner was gradually extinguished in the tunnel type kiln as shown in FIG. Maintained.

As a result, the kaolin brick of the present invention has an average temperature of 1130 ° C., a firing time of 2.5 hours, and a calorific value of combustion: 296,010 kcal. It was confirmed that only five burners are capable of proper firing, thus providing a firing condition that reduces the use of fuel in half compared to the conventional one.

Kaolin bricks prepared by the production method of the present invention as described above 40% by weight, 20% by weight, respectively, by adopting anthracite coal ash containing more unburned residual carbon than kaolin clay and kaolin clay and fly ash in fly ash. , High pressure molding the mixed soil mixed at a blending ratio of 40% by weight in a brick shape, and then dried and calcined, but the unburned residual carbon of the fly ash is self-heated in the firing process, so that the firing temperature is 1130 ° C. in the tunnel kiln. It is manufactured by heating and baking for a baking time of 2.5 hours.

Kaolin brick of the present invention prepared as described above was again confirmed that the physical properties (absorption rate and compressive strength, etc.) is excellent through the following experiment.

[Experiment 1]. Measurement of compressive strength

The compressive strength of brick specimens was measured in accordance with KS L4201 and calculated as follows.

        Compressive Strength C = W / A

        C: compressive strength, N /

        W: maximum load, N

A: pressure area including the opening,

[Experiment 2]. Absorption Rate Measurement

 The apparent absorption and volume specific gravity of the sintered compact were measured in accordance with KS L4008. First, the surface of the calcined specimen having a weight of 10 g or more was roughly ground, and then dried sufficiently until the weight was measured in an oven at 100 ° C., and the weight D was measured. After the dry weight was measured, the specimen was placed in a container containing distilled water, boiled for at least 2 hours, and cooled completely to room temperature. Specimens contained in distilled water in a suspended state using a ring or net accurately measured the weight of each specimen to 0.01g. Subsequently, the weight of the loop or net was weighed at the same position as the first position except for the sample, and the value obtained by subtracting the later value from the initial value was set to underwater weight S. Specimens saturated with distilled water were removed from the container, and the surface was lightly wiped with a damp cloth, and weighed accurately to 0.01 g, and the catcher weight M was measured.

Absorption rate was calculated as the weight ratio of water to dry weight of the specimen as follows.

Absorption rate = (MD) / D × 100

[Experiment 3]. Thermal analysis

The raw materials used for the manufacture of bricks were subjected to thermogravimetric analysis. 10-30 mg of the sample was placed in an alumina crucible and the thermogravimetric decrease was measured by heating at a rate of 20 ° C. per minute in an air atmosphere.

The results of confirming the experiment 1,2,3 are as follows.

[Result 1] Analysis of Raw Material

Table 3 shows the composition of fly ash, which is mixed with clay, clay, kaolin and brick raw materials, which are used for the manufacture of kaolin brick, by wet method.

 Analysis of the ingredients of brick manufacturing raw materials SiO2
(%) Al2O3
(%) CaO
(%) MgO
(%) Fe2O3
(%) K2O
(%) Na2O
(%) TiO2
(%) MnO
(%) P2O5
(%) C
(%) Ig
Loss
(%) Clay 49.2 33.1 7.56 0.21 0.83 0.41 2.98 0.39 0.01 - - 5.27 clay 43.4 34.3 0.13 0.38 4.87 0.54 0.63 1.0 0.06 - - 14.7 Coal fly ash 45.75 29.7 0.94 0.73 3.40 3.66 0.60 3.11 0.04 - 12.0 8.87

The clay is characterized by a high limestone content, and the clay is characterized by a high content of nutrients in the raw materials. In addition, the ash component of fly ash contains 12% of unburned residual carbon and about 6% of components that can act as fluxes such as K2O, Na2O, CaO, and MgO.

In the case of clay, similar to kaolin, weight loss occurs due to the release of crystal water at around 500 ℃. In addition to clay weight loss around 500 ° C, clay also loses weight due to carbonate decomposition between 800 ° C and 1000 ° C. In comparison, the weight loss of coal ash (fly ash) begins at 550 ° C and continues slowly and completes at 1100 ° C. Therefore, when the coal ash (fly ash) is included it can be seen that the firing temperature should be 1100 ℃ or more.

It can be seen that feldspar is 50 µm or more and contains a large number of angular particles, whereas white clay has an average particle size of about 20 µm and a rounded particle shape having a rough surface. Coal ash (fly ash) used as a raw material has a very rounded particle shape with a smooth surface and has a very wide particle size distribution ranging from 2 to 3 μm to 50 μm. .

[Result 2] Plasticity and Physical Properties of Kaolin Bricks with Various Fly Ash Contents

In general, the clay brick is continuously fired for more than 5 hours up to about 1200 ℃. On the other hand, in the case of kaolin bricks containing coal ash (fly ash), the residual carbon and flux components contained in the coal ash (fly ash) induce heat generation of the specimen so that the brick temperature is maintained even when the annealing section is passed through the tunnel kiln.

3 is a diagram showing the firing temperature of the brick required to have a constant absorption rate as the amount of coal ash (fly ash) contained in the brick increases.

As shown in FIG. 3, the firing temperature required to reach a constant absorption rate decreases rapidly as the amount of coal ash (fly ash) increases. However, when the content of coal ash (fly ash) is more than 40%, the plasticity of the raw materials required for the extrusion of bricks is sharply worsened. Therefore, the limit to the use of coal ash (fly ash) without changing the existing production process is 40% by volume. At this time, the firing temperature of the brick containing 40% of fly ash (fly ash) can be seen that more than 1090 ℃. The mechanical properties of bricks are represented by compressive strength, which indicates the load the brick can bear, and by bending strength that resists bending. Compressive strength was measured by the bending strength of the brick prepared above, and are shown in FIGS. 4 and 5.

As a result, it can be seen that kaolin bricks containing coal ash (fly ash) exhibit one kind of KS L4201 clay brick. Therefore, it is confirmed that kaolin bricks including the coal ash (fly ash) of the present invention have mechanical properties that can be used in place of conventional bricks. The criterion for evaluating the superiority of bricks is important not only for the mechanical properties mentioned above, but also for the specific gravity and porosity of the bricks themselves. This is because the lower the bulk specific gravity of the brick, the lighter the brick is, assuming that the mechanical properties of the brick are supported, and therefore, the brick is advantageous not only in thermal efficiency but also in transportation and construction. As a basis for comparing the weight of bricks, there is a method of measuring volume specific gravity and porosity. 6 shows the bulk specific gravity according to the content of coal ash.

Compared with the conventional kaolin wall having a bulk specific gravity of 2 or more, the kaolin brick of the present invention mixed with coal ash was found to have a low volume specific gravity of about 12%.

As shown in the color comparison experiment of calcined brick according to the content of fly ash (fly ash), the inside and outside of the brick show the same color at 10%, 20%, 30% and 40%. However, when the ash content (fly ash) is more than 50%, the interior shows a black carbonized color. These results indicate that when the weight loss of coal ash (fly ash) is completed at 1090 ° C, in the case of specimens containing more than 50% of coal ash (fly ash), the surface of the specimen is completely burned with residual carbon of coal ash (fly ash). It can be seen that was not burned. Therefore, even with the uniformity of the microstructure in mind, similar to the previous results, the firing temperature of the brick should be more than 1090 ℃ 1130 ℃, it can be seen that the maximum content of coal ash can be added is 40%.

However, this color non-uniformity is not considered to have a significant effect on the mechanical strength, and considering that the higher the amount of coal ash (fly ash), the lower the firing temperature, it is confirmed that coal ash (fly ash) helps to generate a glass phase. The development of the glass phase has been shown to promote densification of the specimen, thereby lowering the absorption rate and rounding the shape of the pores, thereby contributing to the improvement of the mechanical strength of the brick. From these results, it was confirmed that the quality of the brick including the fly ash (fly ash) is superior to that of the conventional brick.

[Result 3] Characteristic change according to temperature of brick including 40% of fly ash (fly ash) of the present invention

The more coal ash (fly ash) is included, the lower the firing temperature of the brick and the higher the compressive strength. However, the actual content of fly ash (fly ash) is limited by the plasticity of the raw material of the brick, the realistic possible ash content (fly ash) can be said to be up to 40%. Therefore, it is necessary to examine the characteristics of bricks containing fly ash (fly ash) according to firing temperature in bricks containing 40% coal ash (fly ash).

7 shows the compressive strength according to the firing temperature of the brick containing 40% coal ash (fly ash) as shown in FIG.

The experiment was conducted in an electric furnace, unlike the kiln at the actual production site. As the firing temperature increased, the compressive strength increased, and it was confirmed that the firing temperature should be 1100 ° C. or higher in order to exhibit one or more kinds of clay bricks.

Therefore, the present invention is manufactured by adding fly ash to kaolin clay and kaolin clay, but the high pressure of the brick by the optimal ratio of the properties and blending ratio of the fly ash (fly ash) without the addition of plasticizer 40% by weight It provides optimal conditions for molding, drying shrinkage, heating and firing process and physical properties of bricks (absorption rate, compressive strength, etc.), but lowers the firing temperature by conventional self-heating by unburned residual carbon of the fly ash and tunnel type kiln. It is used as a fired fuel because it reduces the firing time and also passes the non-baking section during firing. Since BC 油 is reduced, it is economical and eco-friendly, and also provides excellent commerciality of bricks by suppressing black core generation, which is a disadvantage of conventional fly ash-added products.

Claims (2)

In the manufacture of kaolin bricks by high pressure molding a mixture of kaolin clay, kaolin clay and fly ash into a brick shape, and then drying and calcining,
A process of mixing an anthracite coal ash containing more unburned residual carbon than coal bituminous coal ash in the kaolin clay, kaolin clay, and fly ash, respectively, in a mixing ratio of 40% by weight, 20% by weight, and 40% by weight;
A brick forming process of molding the mixed soil mixed in the mixing process under high pressure (200 hp) in a vacuum state;
Drying process of drying the molded bricks and heating and baking the dried bricks in a tunnel-type kiln, heat firing at 1130 ℃ for 2.5 hours by self-heating of unburned residual carbon of the fly ash (fly ash) added to the bricks Fuel-saving kaolin brick manufacturing method using a fly ash, characterized in that produced by the heating and firing process.
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