KR20030048225A - Concrete compositions using bottom ash and method of making - Google Patents

Abstract

PURPOSE: A concrete composition using bottom ash and its preparation method are provided, to lower the manufacturing costs, to improve the long period compression strength and to obtain the color similar to natural one. CONSTITUTION: The concrete composition comprises 15-30 wt% of concrete; 15-45 wt% of a first bottom ash as a coarse aggregate; 20-35 wt% of a second bottom ash as a fine aggregate; and 10-20 wt% of powdered stone. Preferably the first bottom ash has a particle size of 5-20 mm and the second bottom ash has a particle size less than 5 mm. The first bottom ash and the second bottom ash are the waste oxide generated in a boiler of a steam power plant at a high temperature of 1,500 deg.C after the combustion of coal. Optionally the composition comprises further 5-15 wt% of red mud for expressing the composition yellow soil color, and sulfuric acid is added to neutralize the red mud, thereby generating sodium sulfate.

Description

Concrete compositions using bottom ash and method of making}

The present invention relates to a concrete composition using a bottom ash and a method for manufacturing the same, in particular, a concrete composition using a bottom ash used in a vegetation large-scale greening revetment block or outdoor parking lot floor pavement and embankment revetment block that has recently been in the spotlight. It relates to a manufacturing method.

That is, the present invention is a substitute for natural aggregates and artificial aggregates that are gradually depleted, such as bottom ash generated after coal combustion of thermal power plants, stone powder generated in quarries, red mud generated in alumina production process, and the like. The present invention relates to an eco-friendly large greening bank block, embankment bank block or outdoor parking lot paving concrete composition by recycling industrial waste, and a method of manufacturing the same.

In general, coal ash generated as a by-product from coal-fired power plants is a residual mineral remaining after the combustion of organic combustible components of coal in a combustion furnace, and bottom ash (floor ash or low ash) discharged to the bottom of the combustion furnace. It is divided into fly ash (fly ash) discharged to the upper side together with combustion gas. Since these coal ashes are collected at different locations in the combustion facility, physical properties such as sintered state, density, and particle size are different.

Fly ash is a fine-sized particle from the coal ash produced during the combustion process and is discharged through the combustion furnace together with the combustion gas. Generally, the ash ash is referred to as fly ash, since it occupies 75 to 90% of the total ash generated. do. The quality of fly ash is improved with the improvement of power generation facilities, and its recycling rate is gradually increasing to 32.2% in 1998 and 42.5% in 1999, and more than 90% is used as concrete admixture and cement raw material.

On the other hand, the bottom ash is a particle formed by the sintering in the combustion furnace to fall to the lower part of the boiler to crush the solidified material to a particle size of 25mm or less using a grinder. Generally, the bottom ash crushed by the grinder has a particle size range of about 1 to 20 mm and is also referred to as a clinker ash or bad ash. This bottom ash generates about 10-15% of the total ash production.

Usually, these coal ashes, which are by-products of coal-fired power plants, were treated mainly at the coal ash processing plant (company head) installed at the point where environmental preservation and resource recycling were emphasized. In the past, when the utilization of land was high, it was rather easy to process, but it is relatively difficult to find a manager who needs three to four times the size of the power plant facilities due to the rapid increase in factory land and land price due to the recent high economic growth rate. The reality is getting harder.

Therefore, fly ash has been used in various fields such as cement admixtures, landfills, land improvement materials, lightweight aggregates, etc., as a result of steady research in various research institutes and academia. Furnaces are active, accounting for about 90% of the total recycling rate.

US patent publication US Pat. 6,068,131, US pat. 5,936,216, US pat. 5,5456,363, US pat. 5,227,047, US pat. 6,123,813, US pat. 6,074,458, US pat. 6,064,022, US pat. 5,967,331, US pat. 5,944,875, US pat. 5,513,755, US pat. 6,038,987, US pat. 5,976,331, US pat. 5,887,724, US pat. 5,299,692, US pat. 5,868,084, US pat. 5,749,308, US pat. 5,735,403, US pat. 5,555,821, US pat. 5,399,194, Korean Patent Publication 1996-033525, Korean Patent Publication 1997-068549, Korean Patent Publication 1997-046374, Korean Patent Publication 1996-027658, Korean Patent Publication 1996-026663, Korean Patent Publication 1996-026662, Korean Patent Publication 1997-000749 , Korean Patent Publication No. 1996-033525, Korean Patent Publication No. 1996-073565, Korean Patent Publication 1994-000209, Japanese Patent Application Publication No. 05-138151 and the like.

However, in most cases of bottom ash, it is simply landfilled at the company site around the power plant, mixed with fly ash inland or coastal landfill, and used in small amounts as roadbed soil material around the power plant. Therefore, as a main material causing the problem of environmental pollution, as well as the difficulty of securing the processed paper, the treatment thereof has become a problem.

In addition, as an example of a technique using a bottom ash, which is a coal ash of a power plant in a concrete composition, Korean Laid-Open Patent Publication No. 97-074076 discloses an example in which about 30% of the total aggregate is replaced by a concrete panel manufacturing method. In Publication No. 97-061815, there is an example of using some composition as a method for manufacturing lightweight building materials using by-products of a thermal power plant.

In addition, the recently developed large-scale planting revetment block capable of growing large plants can prevent soil deterioration and facilitate the discharge of water that has soaked into the ground during rainy weather. It is manufactured from aggregate.

However, since the weight of the green-eye block is slightly different depending on the standard, but is generally about 150 ~ 450kg, the operator uses a hydraulic conveying device or a raft block for transporting the ban block. Care is required.

In addition, the compressive strength of the product is about 180kg / ㎠ or more in the KS standard and the ground part of the structure requires a porous structure that can easily extend the root of the plant.

An object of the present invention is to solve the problems described above, to provide a concrete composition using a bottom ash and a method for producing the same that can produce a product that can meet a variety of requirements.

Another object of the present invention is a bottom ash, which is relatively inexpensive to produce compared to the conventional product, and also has a light weight, concrete structure capable of plant growth, and can produce a product whose appearance is close to natural colors such as ocher color. It is to provide a concrete composition and a method for producing the same.

Another object of the present invention is to recycle industrial wastes such as bottom ash generated from coal-fired thermal power plant, stone powder generated from quarries, red mud generated from alumina production process, etc. It is to provide a concrete composition using the bottom ash and a method for producing the same.

That is, the present invention is to produce alumina by treating a large amount of stone powder and bauxite generated after producing aggregates such as artificial sand or gravel from the bottom ash, a coal-fired waste of coal-fired power plant as a substitute of natural or artificial sand or gravel It is to provide a concrete composition and a method of manufacturing the same using red mud generated as waste in a factory.

1 is a view showing the appearance and structure of the bottom ash (5-20mm size) according to the present invention

Figure 2 is a plant rooting model diagram when applying the greening revetment block according to the present invention

3 is a view showing a comparison of the color of the red mud and the non-added case in the revetment block for greening according to the present invention

In order to achieve the above object, the concrete composition of the present invention utilizes waste in a concrete composition used in a large green block, outdoor parking lot packaging, or a bank block for embankment, wherein the waste is a bottom ash which is a waste generated from a thermal power plant. The concrete composition is composed of 15 to 30% by weight of cement, 15 to 45% by weight of the first bottom ash as coarse aggregate, 20 to 35% by weight of the second bottom ash as fine aggregate, and 10 to 20% by weight of stone powder. .

Moreover, in the concrete composition of this invention, the particle size of the said 1st bottom ash is 5-20 mm, The particle size of the said 2nd bottom ash is characterized by being less than 5 mm.

In the concrete composition of the present invention, the first bottom ash and the second bottom ash are characterized in that the oxide is produced at a high temperature of 1,500 ° C. or higher in a boiler of a thermal power plant.

In the concrete composition of the present invention, red mud is added in an amount of 5 to 15% by weight so that the color of the composition of the concrete is expressed in a natural friendly ocher color.

In addition, in the concrete composition of the present invention, sulfuric acid is added for neutralization of the red mud, and thus sodium sulfate is produced.

Method for producing a concrete composition of the present invention in order to achieve the above another object is a method of manufacturing a concrete composition used in large greening blocks, outdoor parking lot packaging or embankment banks by using waste, (i) coal combustion in thermal power plants A step of preparing a bottom ash, which is a waste generated after. (Ii) separating the bottom ash into coarse aggregates and fine aggregates according to the particle size, and separating the first and second bottom ashes, (i) preparing stone powder generated from quarries, and (iii) alumina production process. A step of providing a red mud generated in the step 15, 45 to 45% by weight of the first bottom ash, 20 to 35% by weight of the second bottom ash provided in each of the steps (i) to (iii), 10 A concrete composition is formed by mixing 15-30 wt% of cement with -20 wt% and 5-15 wt% of red mud.

In addition, the method for producing a concrete composition of the present invention, characterized in that it further comprises the step of generating sodium sulfate by adding sulfuric acid for the neutralization of the red mud.

First, the outline | summary of this invention is demonstrated.

The present inventors replaced the aggregates such as sand or gravel with the whole ash of bottom ash and the quarries waste among the components of the concrete composition for the large-scale greening revetment block for conventional greening, and have better physical properties and eco-friendly than the existing products. We wanted to develop the technology to produce the product.

The inventors of the present invention are about 15-30% by weight of cement, and 15-45% by weight of bottom ash A (5-20mm) with coarse aggregate. As a fine aggregate, a concrete composition including 20 to 35% by weight of bottom ash B (less than 5 mm), 10 to 20% by weight of stone powder, and 5 to 15% by weight of red mud was prepared.

Table 1 shows the chemical composition of each material of these compositions, and Table 2 shows the qualitative analysis of industrial ash bottom ash, stone powder, and red mud materials, which may cause problems of heavy metal content and environmental pollution due to their dissolution. It is to examine whether it can.

According to the analysis results of the present inventors, the content of harmful heavy metals such as Pb, Cd, Cr, Cu, etc. is extremely small (10 ^{-2 to -4} ), and bottom ash is formed as an oxide at a high temperature of about 1,500 ° C or more in a coal boiler. Therefore, it can be seen that the concrete composition according to the present invention does not generate environmental pollution due to heavy metal elution.

Table 1. Chemical Composition of Concrete Composition Materials

Ingredient Type CaO Al ₂ O ₃ SiO ₂ MgO Fe ₂ O ₃ K ₂ O Na ₂ O TiO ₂ SO ₃ cement 60.14 8.84 20.07 2.49 1.41 0.86 0.28 - 2.53 Bottom ash 0.83 28.90 52.20 0.30 9.77 1.38 0.35 1.98 - Stone powder 1.65 17.20 59.20 0.98 2.64 5.38 1.87 0.28 0.50 Red mud 8.90 22.40 20.30 0.30 15.50 0.03 11.00 6.67 <0.1

Table 2. Qualitative Analysis of Bottom Ash, Stone Flour and Red Mud Materials

(Bottom ash)

ingredient Content (wt.% Order) ingredient Content (wt.% Order) ingredient Content (wt.% Order) Fe 10 ⁰ V 10 ^-4 Ca 10 ^{0 to 1} Pb ND Ni 10 ^-4 Al 10 ^{0 to 1} Ga 10 ^-4 Cu 10 ^-3 K 10 ^{-1 to 0} Si 10 ^{0 to 1} Na 10 ^-1 Sr 10 ^-2 Mg 10 ^-1 Ti 10 ^-1 Cr 10 ^-3 Mn 10 ^-2 Zr 10 ^-3 Ba 10 ^-2

(Stone powder)

ingredient Content (wt.% Order) ingredient Content (wt.% Order) ingredient Content (wt.% Order) Fe 10 ^{-1 to 0} V 10 ^-4 Ca 10 ^-1 Pb 10 ^-2 Ni 10 ^-3 Al 10 ^{0 to 1} Ga 10 ^-4 Cu 10 ^-3 K 10 ⁰ Si 10 ^{3 to 1} Na 10 ^{-1 to 0} Sr 10 ^-3 Mg 10 ^-1 Ti 10 ^-1 Cr 10 ^-3 Mn 10 ^-2 Zr 10 ^-3 Ba 10 ^-2

(Red mud)

ingredient Content (wt.% Order) ingredient Content (wt.% Order) ingredient Content (wt.% Order) Fe 10 ^{0 to 1} V 10 ^-3 Ca 10 ^{0 to 1} Pb 10 ^-4 Sn 10 ^-3 Al 10 ^{0 to 1} Ga 10 ^-4 Cu 10 ^-4 K 10 ^-2 Si 10 ^{0 to 1} Na 10 ⁰ Sr 10 ^-3 Mg 10 ^-1 Ti 10 ⁰ Cr 10 ^-2 Mn 10 ^-2 Zr 10 ^-1 Ba ND

On the other hand, the characteristics of the concrete composition according to the present invention is to use the bottom ash, a kind of coal ash as coarse aggregate or fine aggregate, the bottom ash has good porosity and its porosane characteristics, its structure is porous (see Fig. 1). It shows long-term strength expression and has good water absorption and good porosity, so that the root of the plant can be easily rooted (see Fig. 2).

On the other hand, the addition of red mud is a high iron content of the yellow earth color to give the appearance of a natural friendly texture (see Fig. 3), by adding sulfuric acid to neutralize the alkali (Na ₂ CO ₃ ) of the component sodium sulfate ( Na ₂ SO ₄ ) can be produced to simultaneously obtain the effect of admixtures to increase the initial strength of concrete.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

1 is a view showing the appearance and structure of the bottom ash (5 ~ 20㎜ size) according to the present invention, Figure 2 is a plant rooting model diagram when applying the green eye protection block according to the present invention, Figure 3 In the green-eye block for greening according to the present invention, the red mud is added to the color of the non-added color.

That is, Figure 1 is a photograph showing the appearance of the bottom ash of about 5 to 20 mm size used as coarse aggregate in the present invention, the bottom ash is a light weight of about 1.5 to 2.0 porous structure and apparent specific gravity similar to volcanic rock.

The present inventors manufactured the mortar by changing the material and water ratio blended with the above-mentioned concrete composition ratio in the range of W / C 0.3 to 1.0, and injecting the mortar into a circular mold to produce a specimen. It was injected into the vibratory compaction to prepare a green eye block.

The product measured the compressive strength by age and compared the results with each other.

In this table, when the artificial aggregate is used in the comparative example, the weight of each block (per unit volume) is about 350 kg (standard 360 type A, 1000x1000x260), and the 28-day strength is about 200 kg / ㎠, Compared with the results of using the bottom ash of Examples (1-7) as aggregate, the weight is about 260 kg, the strength is about 230-320 kg / ㎠ and the weight is about 100 kg / lighter about 25 per unit volume It can be seen that the reduction is more than% and the strength is increased by about 20% or more.

Table 3. Experimental Results of Green Block Manufacturing

Material used and compounding ratio (kg / block 1) Compressive strength (㎏ / ㎠) cement BA (A) (# 67) BA (B) (Fine aggregate) Crushed Aggregate Stone powder Red mud Reducing Agent (%) W / C 3 days 7 days 28 days Comparative example 48 - - 151 151 - 0.40 0.50 - - 200 Example 1 40 80 70 - 70 - 0.40 0.55 112 143 230 Example 2 40 70 80 - 60 12 0.40 0.55 115 140 236 Example 3 44 75 75 - 60 12 0.36 0.56 130 187 250 Example 4 44 115 55 - 30 12 0.36 0.56 174 198 308 Example 5 44 125 60 - 35 9 0.36 0.60 229 258 320 Example 6 48 82 82 - 33 13 0.33 0.58 144 167 236 Example 7 50 115 55 - 30 15 1.0 0.50 180 204 320

※ BA (A) = bottom ash 5-20 mm, BA (B) = bottom ash 0.08-5 mm,

Artificial aggregate = 25 mm or less (crushed aggregate), stone powder = 150 mesh or less (0.104 mm),

Reducing agent = Bioflo (better biotech =% of cement), W / C = water / cement ratio

As mentioned above, although the invention made by this inventor was demonstrated concretely according to the said Example, this invention is not limited to the said Example and can be variously changed in the range which does not deviate from the summary.

That is, in the above embodiment, the concrete for the greening block has been described, but the present invention is not limited thereto. Of course, the concrete for the greening block can be used for the protection block for preventing the loss of the bank and the water channel.

As described above, according to the present invention by constructing a concrete composition using only the total ash and bottom ash as aggregate without using any natural or artificial aggregate at all, the production cost is significantly reduced and the long-term compressive strength is larger than the existing product, It was possible to produce environmentally friendly products with concrete structures that are effective for growth and whose color is similar to natural colors.

Claims (7)

In the concrete composition used for the large green block using waste, outdoor parking lot packaging or embankment protection block, The waste is a bottom ash which is a waste generated from the thermal power plant is used, The concrete composition is composed of 15 to 30% by weight of cement, 15 to 45% by weight of the first bottom ash as coarse aggregate, 20 to 35% by weight of the second bottom ash as fine aggregate, and 10 to 20% by weight of stone powder. . The method of claim 1, The particle size of said first bottom ash is 5-20 mm, and the particle size of said second bottom ash is less than 5 mm. The method of claim 2, The first bottom ash and the second bottom ash is a concrete composition, characterized in that the oxide produced at a high temperature of more than 1,500 ℃ in the boiler of the thermal power plant. The method of claim 1, Concrete composition, characterized in that 5 to 15% by weight of red mud is added so that the color of the composition of the concrete is expressed in a natural friendly ocher color. The method of claim 4, wherein To the neutralization of the red mud is added sulfuric acid, which results in the production of sodium sulfate. As a method for producing a concrete composition used for large greening blocks utilizing waste, outdoor parking lot packaging or embankment protection block, (Iii) preparing a bottom ash, which is a waste generated after coal combustion in a thermal power plant, (Ii) separating the bottom ash into first and second bottom ash to separate and use the coarse aggregate and the fine aggregate according to the particle size; (Iii) preparing steps for preparing stone powder from quarries, etc .; (Iii) providing a red mud produced in the alumina production process, 15 to 45% by weight of the first bottom ash, 20 to 35% by weight of the second bottom ash, 10 to 20% by weight of stone powder, and 5 to 15% by weight of red mud provided in each of the steps (i) to (v). Process for producing a concrete composition to produce a concrete composition by mixing 15 to 30% by weight of cement. The method of claim 6, Method for producing a concrete composition, characterized in that it further comprises the step of producing sodium sulfate by adding sulfuric acid for the neutralization of the red mud.