KR100633781B1 - Cement additive manufacture method for using bottom ash of thermoelectric power plant - Google Patents

Abstract

The present invention relates to a cement additive manufacturing method using a thermal power plant flooring, in particular in the flooring of a thermal power plant boiler; A cooling step of cooling the bottom ash with air without seawater cooling treatment; A grinding step of grinding the flooring material cooled in the cooling step with a grinder; A sorting step of sorting the bottom ash crushed in the crushing step to 50 mesh or less by particle size classification; A powder manufacturing step of grinding the flooring material pulverized in the screening step with a ball mill to produce a specific surface area of the powder of the flooring material of 2,000 to 4,000 cm ² / g; And mixing the bottom ash fine powder selected in the powder manufacturing step with 5 to 15% by weight of Portland cement.

According to the present invention made as described above to avoid the conventional method of drying and disposal of the thermal power plant flooring material and landfilled so that the thermal power plant flooring material can be utilized as cement additives by mixing a certain amount in the cement of Portland to produce cement Long-term strength, heat of dehydration and chemical resistance can be improved.

Thermal power plants, flooring, pozzolanic reactivity, cement additives, air cooling

Description

Cement additive manufacture method for using bottom ash of thermoelectric power plant}

1 is a flow chart showing the operation of the cement additive manufacturing method using a thermal power plant flooring according to the present invention,

Figure 2 is a process chart showing the treatment process of the cement additive manufacturing method using a thermal power plant flooring according to the present invention,

Figure 3 is a graph showing the results of the XRD analysis by particle size of the thermal power plant flooring according to the present invention.

<Explanation of symbols on main parts of the drawings>

10: boiler 11: flooring

100: cooler 110: grinder

120: ball mill

The present invention relates to a method for producing cement additives, and in particular, by selecting a portion having a pozzolanic reactivity in the floor ash generated in the thermal power plant to mix a certain amount in the cement to improve the long-term strength, heat of low hydration and chemical durability of the concrete It relates to a method for producing cement additives using thermal power plant flooring.

In general, thermal power generation refers to a method in which water obtained by burning coal in a boiler is used to cut water into steam, and the turbine is rotated with steam to generate rotational power and generate electricity from a generator connected to the turbine side.

The place that produces these thermal power plants is called thermal power plant, and the coal ash generated from the boiler of thermal power plant is usually divided into fly ash and floor ash according to the generation position, and the fly ash is generated at the ratio of 80% by weight and floor ash by 20% by weight. do.

The generated fly ash has a powder level of about 3,000-5,000 cm ² / g of powder, which is almost similar to cement particles. Such fly ash is not hydrophobic in itself, but pozzolanic activity, that is, soluble silica and alumina contained in fly ash, reacts slowly with calcium hydroxide, which is produced when the cement is hydrated, at room temperature. It has a property of forming a hydrate of to form a stable compound insoluble in the long term.

In addition to these characteristics, the fly ash forms a spherical shape, which increases the fluidity and is widely used as a concrete admixture.

On the other hand, the bottom ash is cooled in seawater after generation, and its particle diameter is collected at the bottom of the boiler about 1-2.5mm and is mostly discarded in the ash pond after crushing. As such, most flooring materials are disposed of and disposed of, but the flooring material is also a material quenched at a high temperature of 1,500 ° C. or higher, thus exhibiting the same characteristics as fly ash, so that it is highly usable as a mixed material. However, when used as admixtures, the particle size is large, the salt content is high, and the content of unburned carbon is uneven, so that countermeasures should be prepared.

Thermal power plant flooring materials are poorly recyclable because of their poor particle size and large particle size. Thermal power plants are mainly located in coastal areas, and conventional thermal power plant flooring materials are not recycled and have been disposed of in their own company's landfills. .

However, due to the saturation of the heads of existing workplaces, it becomes difficult to dispose of landfills at the heads of workplaces, and it is difficult to secure a place to secure new heads of workplaces. The perception of recycling flooring is higher than ever.

Several studies have been conducted to utilize thermal power plant flooring as an alternative to aggregate or cement additives.However, it is economical to use it in concrete, such as problems in the treatment process such as drying and chlorine in seawater causing corrosion of steel in concrete. Not suitable for process and final product quality.

In particular, thermal power plant flooring is known to have pozzolanic reactivity, but as an additive for general use in concrete, the content of chlorine is essentially limited in order not to cause corrosion such as reinforcing steel and is generally buried in seawater. In order to use the thermal power plant flooring material disposed of as cement additives as it is in concrete, there is a problem in that it is not suitable for general use in the amount of disposal and concrete with the deterioration of physical properties of concrete.

The present invention is to solve the problems as described above, to avoid the conventional method of drying and disposal of the thermal power plant flooring material is buried in the seawater so that the thermal power plant flooring material can be utilized as cement additives by mixing a certain amount of cement in Portland cement It is to provide a method for producing cement additives using thermal power plant flooring to improve the long-term strength, heat of low hydration and chemical resistance of concrete by manufacturing.

In addition, the present invention is to provide a method for producing a cement additive using a thermal power plant flooring material that can improve the environmental added value by effectively saving the natural resources and reducing the cost of raw materials and the use of the landfill waste when manufacturing cement. There is.

In addition, the present invention utilizes coal ash bottoms generated in thermal power plants as cement additives by selectively selecting the pozzolanic properties of the floorings by particle size classification and pulverization of thermal power plant floorings. Eggplant is to provide a method for producing cement additives using thermal power plant flooring that can solve the problems of inhibition of pozzolanic reactivity, drying and obstacles to general use in concrete by chlorine components in seawater.

Features of the present invention for achieving the above object,
In the flooring of a thermal power plant boiler; A cooling step of cooling the bottom ash with air without seawater cooling treatment; A grinding step of grinding the flooring material cooled in the cooling step with a grinder; A sorting step of sorting the bottom ash crushed in the crushing step to 50 mesh or less by particle size classification; A powder manufacturing step of grinding the flooring material pulverized in the screening step with a ball mill to produce a specific surface area of the powder of the flooring material of 2,000 to 4,000 cm ² / g; And mixing the bottom ash fine powder selected in the powder manufacturing step with 5 to 15% by weight of Portland cement.

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Hereinafter, the method for producing cement additives using the thermal power plant flooring according to the present invention will be described in detail with reference to FIGS. 1 to 3.

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1 is a flow chart showing the operation flow of the cement additive manufacturing method using a thermal power plant flooring according to the present invention, Figure 2 is a process chart showing the treatment process of the cement additive manufacturing method using a thermal power plant flooring according to the present invention, Figure 3 is a graph showing the results of the XRD analysis by the particle size of the thermal power plant flooring according to the present invention.

1 to 2, in the cement additive manufacturing method using the thermal power plant flooring according to the present invention, the flooring material 11 of the boiler 10 is transferred using a conveyor belt or the like, and then passed through the cooler 100 to the flooring material. Cooling step (S100) for cooling the air (11) with air without sea water cooling treatment, and the grinding step (S110) for crushing the flooring material 11, which is cooled through the cooler 100 in the cooling step and free-falls with the grinder 110 And, the screening step (S120) for sorting the bottom ash fine powder 11 prepared in the crushing step to 50 mesh or less by the particle size classification, and grinding the flooring material pulverized in the screening step with a ball mill (120), specific surface area Mixing step (S130) of preparing a flooring powder (11) of 2,000 ~ 4,000cm ² / g and mixing the flooring powder (11) selected in the powder manufacturing step with 5 to 15% by weight in Portland cement ( S140) is characterized by.

On the other hand, particle size classification means separating raw materials according to chemical composition, particle diameter, shape, color, density, radioactivity, magnetic and electrostatic properties. An operation that divides into two or more particle groups, also called classification.

First, the present invention is characterized by producing a cement additive by screening the flooring material of thermal power plant, which is a waste by-product, not natural raw materials, by particle size classification.

Instead of cooling by floor water, the bottom of the thermal power plant generated by the thermal power plant is cooled by air, and selected and pulverized only a portion of 50 mesh or less is mixed and manufactured by mixing about 5 to 15% by weight in Portland cement.

Table 1 shows the results of chemical components analysis by particle size after quenching the floor of thermal power plant generated by thermal power plants with air.

As shown in Table 1, the main components of the flooring material were SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , CaO, and their contents were 90% by weight or more, and the specific gravity was 2.73.

TABLE 1

Chemical Composition by Thermal Particles of Thermal Power Plant Floor Unit (Unit: wt%)

Particle size (mesh) SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO K ₂ O Na ₂ O TiO ₂ MnO P ₂ O ₅ L.O.I Cl (mg / kg) Total 51.77 21.99 15.68 4.42 0.88 1.05 0.34 1.09 0.13 0.47 1.81 1005.1 +4 52.23 22.89 15.48 4.36 0.87 1.02 0.30 1.17 0.13 0.46 0.30 499.9 -4 / + 8 51.99 22.77 16.11 4.98 0.96 1.07 0.33 1.11 0.12 0.51 0.18 499.9 -8 / + 16 53.17 23.41 14.53 4.68 0.88 1.03 0.32 1.15 0.12 0.53 0.32 499.9 -16 / + 30 52.48 21.90 16.42 4.29 0.84 1.03 0.32 1.04 0.14 0.45 0.55 599.8 -30 / + 50 52.95 21.36 15.92 4.62 0.85 1.01 0.32 1.02 0.14 0.44 1.25 649.8 -50 / + 100 52.48 20.65 13.19 4.88 0.85 1.08 0.36 0.97 0.13 0.42 4.73 1,599.5 -100 / + 200 49.16 19.51 16.30 4.05 0.91 1.14 0.45 0.95 0.15 0.41 7.23 2,299.3 -200 / + 270 46.70 18.91 21.96 3.59 0.90 1.02 0.40 0.99 0.16 0.44 4.96 2,999.3 -270 52.92 22.60 13.51 3.52 0.68 1.02 0.41 1.14 0.08 0.52 3.70 1,999.4

Table 2 shows the pozzolanic reactivity according to the Korean Industrial Standard (KS L 5405) by crushing the thermal power plant floorings divided by particle size to 270 mesh or less. As it satisfies this, it can be utilized as an additive for cement and concrete.

TABLE 2

Pozzolanic Reactivity by Particle Size of Thermal Power Plant Flooring (Unit:%)

Curing time (days) Particle size fraction (mesh) -270 200/270 100/200 50/100 30/50 16/30 8/16 4/8 +4 14 75.2 73.5 73.1 72.1 70.2 71.5 70.4 68.1 64.0 28 95.2 93.0 92.7 91.5 91.0 89.1 86.5 78.2 75.4

And, Figure 3 shows the XRD analysis results by particle size of the thermal power plant flooring according to the present invention, the main mineral phase of the thermal power plant flooring is mullite (Al ₆ Si ₂ O ₁₃ ) and SiO ₂ (quartz, tridymite, crystobalite), hematite (Fe ₂ O ₃ ) and anorthite [(Ca, Na) (Al, Si) ₂ Si ₂ O ₈ ] were also present. In particular, SiO ₂ was mainly present as quartz and tridymite at small particle sizes below 50 mesh and as crystobalite at above particle sizes.

As described above, attention is paid to the chemical and mineral properties according to the particle size of the thermal power plant flooring, and particles of 50 mesh or less having excellent pozzolanic reaction characteristics can be selected, powdered, and used as cement additives.

Hereinafter, the present invention will be described in more detail with reference to Examples.

<< Example 1 >>

A thermal power plant flooring material having a chemical composition as shown in Table 1 was selected for particle size of 50 mesh or less by particle size classification, and pulverized in a ball mill to produce a thermal power plant flooring powder having a specific surface area of 4,000 cm ² / g.

The fine powder of crushed thermal power plant floor ash was replaced by 5 to 15% by weight based on ordinary Portland cement. Same as

TABLE 3

Compressive strength of mortar according to the present invention

division Compounding ratio (% by weight) Compressive strength (kg / cm ² ) Common Portland Cement (OPC) Thermal Power Plant Flooring (BA) 3 days 7 days 28 days Comparative example 100 0 236 340 420 Example 95 5 253 346 429 90 10 254 345 450 85 15 227 324 442

As a result, the compressive strength expression rate showed the characteristics to improve with the physical filling properties compared to the ordinary portland cement as a comparative example.

<< Example 2 >>

As in Example 1, the thermal power plant fine powder was prepared and the physical properties of the uncured and hardened concrete were measured.

Table 4 shows a concrete mix design table of ordinary Portland cement (OPC), which is a comparative example, and 5, 10, 15 wt% replacement of thermal power plant floor (BA) in ordinary Portland cement (OPC), an embodiment of the present invention.

TABLE 4

division G _max (mm) Goal Workability W / C (%) S / a (%) W (㎏ / ㎥) Unit material amount (㎏ / ㎥) Slump (cm) Air volume (%) C BA Comparative example OPC 25 15 ± 2.5 5 ± 1.5 55.0 49.5 165 300 - 892 959 Example BA 5% 282 18.0 891 958 BA 10% 264 36.0 890 957 BA 15% 255 45.0 889 956

The slump of concrete increases when substituted for ordinary Portland cement according to the invention, and its flow rate also increases in high flowable concrete. Especially in the case of concrete with a large amount of binder, the effect of improving flowability and deformation is great.

In addition, since the fly ash of the thermal power plant has a small amount of unburned carbon and the adsorption amount of the chemical admixture is relatively small, the amount of the admixture necessary to obtain the same workability is smaller than that of the case of using portland cement alone.

The compressive strength of the hardened concrete was carried out, and the results are shown in Table 5.

TABLE 5

Compressive strength of concrete according to the invention

division Compounding ratio (% by weight) Compressive strength (kg / cm ² ) Common Portland Cement (OPC) Thermal Power Plant Flooring (BA) 7 days 28 days Comparative example 100 0 229 362 Example 95 5 255 387 Example 90 10 231 360 Example 85 15 223 336

As a result, it can be seen that the strength is more than equivalent to that of the ordinary Portland cement.

Therefore, the thermal power plant flooring prepared according to the present invention can improve the initial and long-term strength improvement rate of cement by selectively separating and pulverizing particles having a pozzolanic activity of 50 mesh or less and increasing the specific surface area. .

As described above, according to the cement additive manufacturing method using the thermal power plant flooring material according to the present invention, the thermal power plant flooring material, which is previously disposed of landfilled in seawater, is cooled by air, pulverized, mixed with cement, and used for long-term strength. And by lowering the heat of hydration, chemical resistance, etc., it is possible to lower the unit cost of the cement raw materials, and substantially recycle the landfill resources.

Claims (2)

In the flooring of a thermal power plant boiler; A cooling step of cooling the bottom ash with air without seawater cooling treatment; A grinding step of grinding the flooring material cooled in the cooling step with a grinder; A sorting step of sorting the bottom ash crushed in the crushing step to 50 mesh or less by particle size classification; A powder manufacturing step of grinding the flooring material pulverized in the screening step with a ball mill to produce a specific surface area of the powder of the flooring material of 2,000 to 4,000 cm ² / g; And Method for producing a cement additive using a thermal power plant flooring, characterized in that the mixing step consisting of mixing the powder of the flooring material selected in the powder manufacturing step to 5-15% by weight in Portland cement. delete

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