KR101468363B1 - Solidifiying Composion Using Subbituminous Coal - Google Patents

Abstract

The present invention relates to a solidification agent composition for flimsy ground using a subbituminous coal by-product, wherein the subbituminous coal by-product having a low content of silicon dioxide (SiO_2) generated during electricity generation in a CFBC boiler of a power plant, is blended with fly ash, and the resultant blend is mixed with a raw material of an eco-friendly solidification agent to be utilized for a solidification agent composition for treating sludge, construction waste soil, inorganic sludge, or the like on flimsy ground or river bottom. According to an exemplary embodiment of the present invention, the solidification agent composition includes: 15-42 wt% of Portland cement; 25-35 wt% of slag; 20-30 wt% of an ash blending containing 45 % or more of silicon dioxide, which is a blending of 20-40 wt% of a subbituminous coal by-product and 60-80 wt% of fly ash containing 45 % or more of silicon dioxide; 10-15 wt% of paper ash; and 3-5 wt% of calcium sulfate.

Description

{Solidifiying Composion Using Subbituminous Coal}

The present invention relates to a fire-retardant composition for soft ground using sub-bituminous coal byproducts, and more particularly, to a fire-retardant composition for sub-bituminous coal which has a low content of silicon dioxide (SiO ₂ ) The present invention relates to a fire-retardant composition for soft ground using sub-bituminous coal by-products, which is used in a fire-fighting composition for treating soft grounds, onitos on a river floor, construction residues and inorganic sludge.

At present, the price of coal is rising rapidly in the world. Among these, bituminous coal (bituminous coal) which is low in moisture and high in calories is high in price and difficult to obtain. The coal-fired power plant is expected to increase the use of sub-bituminous coal by using mixed bituminous coal, which has a large amount of reserves and low price, in conventional PC boilers or by expanding the use of sub-bituminous coal in CFBC, . As a by-product of KS L 5405 (fly ash) of KS L 5405 (fly ash, bottom ash) of bituminous coal, it is used as concrete pozzolan mixed material by processing the generated bitumen. (Fly ash, bottom ash) of circulating fluidized bed boilers are being processed or buried at high cost by some cement companies due to insufficient amount of silicon dioxide (SiO ₂ ).

The reason why the bituminous coal byproducts (fly ash, bottom ash, etc.) generated after being used in the power plant boiler is mainly used is because it satisfies the KS quality standard set by the government. The quality standard is silicon dioxide (SiO ₂ ) 45% or more, 1% or less of moisture, or 5% or less of ignition loss, and the byproducts that can meet these requirements are mainly produced by bituminous coal.

By-products generated from bituminous coal and lignite other than bituminous coal are unsatisfactory in terms of moisture and ignition loss, while the content of silicon dioxide (SiO ₂ ) is less than that of bituminous coal, and the color is partially brown or the apparent specific gravity is low. . The silicon dioxide content is closely related to the pozzolanic reaction of the cement. If the above criteria are not met, the bonding efficiency is not sufficiently generated. For this reason, the content of silicon dioxide (45% or more) is specified in the quality standard of KS L 5405 Respectively.

However, in the case of sub-bituminous coal by-products, it is a fact that some of the cement companies have been disposed of or incinerated because of the high cost of processing due to the insufficient amount of silicon dioxide. In the past, however, the coalification rate of the sub-coal was higher than that of the coal but lower than that of the bit-coal. However, the utilization rate of the sub-coal was increased due to the economical efficiency of the coals and the installation of the coals. This is a large increase.

Therefore, if the sub-bituminous coal industrial by-products (fly ash, bottom ash) processed or buried at the above-mentioned high cost are manufactured by solidification and soft ground and high-function sludge are solidified to be used as soil stabilization and dredged soil, It is thought to be economical because it contributes to resource recycling through the use of materials that can secure the supply amount and lower the cost of construction.

As a background of the present invention, there is a patent registration No. 1393201 entitled " Fire-fighting composition using circulating resources "(patent document 1). In the background art, " pozzolanic compound 65.0 ~ 85.0 wt%; 10.0 to 34.9 wt% of the strength promoting activator; And 0.1 to 5.0% by weight of a dispersant, wherein the pozzolanic synthetic material comprises 45 to 65% by weight of fine blast furnace slag powder; 10 to 45 wt% of fly ash produced from coal-fired power plants; 10 to 45% by weight of a burned material produced from a boiler of a thermal power plant; And more than 0 to 30% by weight of a zeolitic flow catalytic cracking catalyst produced during refining.

The background art uses industrial byproducts as a pozzolanic synthetic material, but it has also been difficult to utilize sub-bituminous coal by-products having a low silicon dioxide content and can not be combined with other components even if sub-bituminous by-products are utilized.

Patent No. 1393201 entitled " Fire-fighting composition using circulating resources "

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method of using fly ash as an eco-friendly fire-fighting material by mixing a sub-bituminous coal by- product having a low content of silicon dioxide (SiO ₂ ) It is not only economical but also solves the problem of high cost of existing firefighting. It is environment friendly firefighting production which does not have secondary pollution to treat soft ground, onitto, construction residue, and inorganic sludge of river bottom. It is an object of the present invention to provide a fire-retardant composition for soft ground using ash by-product of ash.

The present invention relates generally to 15 to 42% by weight Portland cement; 25 to 35% by weight of slag; 20 to 40% by weight of bituminous coal by-products having a silicon dioxide content of 34 to 44% and 60 to 80% by weight of fly ash having a silicon dioxide content of 50 to 60% to form an ash blend 20 having a silicon dioxide content of 45% To 30% by weight; 10 to 15% by weight of paper ash; And 3 to 5% by weight of calcium sulfate. The present invention also provides a fire-retardant composition for soft ground using a sub-bituminous coal by-product.

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Also, it is intended to provide a fire-retardant composition for soft ground utilizing sub-bituminous coal by-products, characterized in that the sub-bituminous by-product has a density of 1.0 to 2.0 g / cm ³ and a powder of 1,000 to 5,000 cm ² / g.

Also, it is intended to provide a fire-retardant composition for soft ground using sub-bituminous coal by-products, characterized in that the slag is 4000 to 6000 cm ² / g and the particle size is 12 to 16 μm.

Also, it is intended to provide a fire-retardant composition for soft ground utilizing sub-bituminous coal by-products, characterized in that calcium sulfate is a desulfurization gypsum which is a flue gas desulfurization gypsum produced by neutralizing sulfur dioxide in exhaust gas of natural anhydrous gypsum or thermal power plant with lime oil .

The fire-retardant composition for soft ground using the sub-bituminous coal by-product of the present invention is prepared by combining the sub-bituminous coal by-product, which has a low content of silicon dioxide (SiO ₂ ) generated during the power generation of the power plant CFBC boiler, with fly ash, To solve the high cost problem of existing firefighting, it is not only economical but also environment-friendly firefighting which has no secondary pollution in processing soft ground, onitto of the river floor, construction residue, and inorganic sludge. There is a very useful effect that can be produced.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings, but the present invention is not limited thereto.

 The fire retardant composition for soft ground using the sub-bituminous coal by-product of the present invention solidifies the soft ground and the high-function sludge by using the by-products (fly ash, bottom ash) In addition, it will reduce the cost of construction and contribute to the recycling of industrial wastes through recycling of industrial wastes.

Hereinafter, the technical structure of the present invention will be described in detail with reference to the preferred embodiments.

The fire retardant composition for soft ground using the bituminous by-products of the present invention usually comprises 15 to 42% by weight of Portland cement; 25 to 35% by weight of slag; 20 to 30% by weight of an ash blend containing 20 to 40% by weight of coarse by-products by-products and 60 to 80% by weight of fly ash containing 45% or more of silicon dioxide and having a silicon dioxide content of 45% or more; 10 to 15% by weight of paper ash; And 3 to 5% by weight of calcium sulfate.

The ordinary portland cement used in the composition of the present invention may specifically be ordinary portland cement specified in KS L 5201. The cement of the above standard is made from clinker obtained by calcining at high temperature (about 1450 degrees) as a raw material containing limestone and clay and contains allyl, bellite, aluminate and ferrite, and most preferably KS L 5201 One kind or crude steel cement may be used.

When the Portland cement is used in an amount of less than 15% by weight, the hard alkalinity required for the hydration reaction of other potentially hydraulic admixtures is insufficient, so that the delay of the initial strength development and the development rate are decreased, and the ground reinforcement performance is lowered.

If it is used in excess of 42% by weight, the economical efficiency is lowered due to the rise of raw materials for fire, and the environmental problems of ground environment and groundwater pollution are caused by strong alkaline and harmful components. In addition, in the case of many niches, the condensation delay of cement may occur.

Therefore, it is preferable to use 15 to 42% by weight of ordinary Portland cement.

The slag can be a variety of well-known slag, and can be used in blast furnace slag produced in the blast furnace such as blast furnace, Finex melting furnace, or steel slag generated in the process of refining steel slag, have.

The slag is used in an amount of 25 to 35% by weight, and hydration reaction by hydration reaction of the slag and hydration reaction by the pozzolan reaction is effective to stabilize the ground by absorption of moisture and intensity development.

When the slag is used in an amount of less than 25% by weight, the hydration reaction and the pozzolan reaction do not sufficiently take place, and the initial strength development is lowered and the performance required for solidification of the ground is lowered.

When the slag is used in an amount exceeding 35% by weight, the hydration reaction by the alkali promoter occurs slowly, the initial strength is low, and the performance of the activity portion is deteriorated.

Therefore, the slag is preferably used in an amount of 25 to 35% by weight.

The powder of the slag is also 3000 cm ² / g or more, preferably 4000 to 6000 cm ² / g, and the particle diameter is 12 to 16 μm.

When the powder is less than 4000 cm ² / g, the pozzolanic reaction caused by the strong alkaline accelerator is reduced, and the solidification performance is lowered, thereby increasing the amount of accelerator and cement.

If the powder is more than 6000 cm ² / g, the economic burden due to the slag processing increases, and the hydration heat due to the high reactivity increases and the field work performance deteriorates.

When the particle diameter is less than 12, the work process is added and the blending performance deteriorates due to particle diameter machining.

When the particle size exceeds 16, there is a problem that the hydration reaction due to the pozzolan reaction is lowered during the solidification process in the solidification process.

The ash blend is formed by combining 20 to 40 wt% of the bituminous by-product by-products and 60 to 80 wt% of the fly ash of the KS standard, wherein the silicon dioxide content is formed to be 45% or more.
The term 'fly ash' in the present invention refers to a conventional fly ash of coal fly ash derived from PC boilers and refers to a by-product suitable for the KS L 5405 quality standard (45% or more of silicon dioxide). In the present invention, the 'by-product of coarse coal by-products' is a by-product from the CFBC boiler, which is a by-product which is different from the main component and the constituent phase of general fly ash and is not suitable for the KS L 5405 quality standard (silicon dioxide: 45% This refers to the wastes that are mostly unutilized and landfilled.

If ash co-by-products are used in excess of 40 wt%, the hydration reaction and the pozzolanic reaction are not sufficiently carried out and the required performance can not be exhibited. When the by-products of sub-bituminous coal is used at less than 20 wt%, fly ash conforming to the KS standard is formed However, it is not economically suitable because it does not use enough bituminous byproducts.

Therefore, in the ash blend, 20 to 40% by weight of the bituminous by-product is mixed with 60 to 80% by weight of the fly ash of the KS standard.

It is preferable to use the sub-bituminous by-product having a density of 1.0 to 2.0 g / cm ³ and a density of 1,000 to 5,000 cm ² / g.

If the density is less than 1.0 g / cm ³ , the weight may be lower than the volume, which may cause problems in mixing and transportation processes due to the increase in volume during the production of the fire.

When the density is higher than 2.0 g / cm ³ , the stabilization performance of the soft ground is decreased because the material is not separated and uniformly mixed with the soil when the fire is applied.

When the powder is less than 1,000 cm ² / g, the reactivity of the bituminous by-product is reduced due to the decrease of the specific surface area, and the sufficient performance is not exhibited due to the decrease of the reactivity.

If the powder is more than 5,000 cm ² / g, the economical burden of processing increases and the price competitiveness of the fire is lowered.

Fly ash, which is a general by-product, preferably has a density of 1.5 to 2.8 g / cm ³ . The general fly ash has a role of strength development through hydration reaction and stabilization effect of soft ground.

When the density is less than 1.5 g / cm ³ , the carbon content is high, so that the hydration reaction by the alkali promoter is lowered and the strength performance is decreased.

When the density is higher than 2.8 g / cm ³ , the iron content is increased and the specific gravity is increased, and the possibility of material separation increases when the ground fire is applied.

As described above, it is preferable that 20-30% by weight of the ash blend mixed with sub-bituminous by-product and fly ash is mixed.

When the ash blend is mixed with less than 20% by weight, the mixing ratio of other admixtures may increase, which may cause a problem of cost increase of the groundfill and the solidification performance is decreased due to the increase of the amount of other admixture, especially cement.

When the ash blend exceeds 30 wt%, the hydration reaction and the pozzolanic reaction do not sufficiently take place compared with the performance of the alkali promoter, so that the strength required for stabilization of the soil can not be exhibited.

In order to evaluate the performance of the fly ash and subbituminous coal byproduct composition according to the above description, silicon dioxide content analysis was carried out using the test method KS L 5405, which was proposed in the fly ash KS standard. In the test method, about 0.5 g of the mixed composition is accurately weighed to 0.1 in a platinum crucible, and the mixed flux is uniformly mixed with the sample. The mixture is slowly heated and cooled, and the melt is washed with a small amount of hydrochloric acid and warm water And the weight is checked by drying. The following silicon dioxide content can be determined using the weight checked later.

A: Content of silicon dioxide

m ₂ : mass of the sample (g)

m ₁ : mass of precipitate

Table 1 to Table 3 show the amount of silicon dioxide content change according to composition combination using the above silicon dioxide content formula.

Fly ash (KS standard), a by-product, when silicon dioxide content is 50%, the amount of silicon dioxide division Sub-bituminous byproduct General by-products (KS standard) Composition Silicon dioxide content unit g Silicon dioxide
content% g Silicon dioxide
content% %  Example 1 200 44 800 50 49.1  Example 2 250 42 750 50 48.3  Example 3 300 40 700 50 47.2  Example 4 350 38 650 50 45.8

Fly ash (KS standard) as a by-product When the content of silicon dioxide is 55%, the amount of silicon dioxide division Sub-bituminous byproduct General by-products (KS standard) Composition Silicon dioxide content unit g Silicon dioxide
content% g Silicon dioxide
content% % Example 1 200 44 800 55 52.2 Example 2 250 42 750 55 50.9 Example 3 300 40 700 55 49.5 Example 4 350 38 650 55 48.7 Example 5 400 36 600 55 46.8

Fly ash (KS standard) as a by-product When the content of silicon dioxide is 60%, the amount of silicon dioxide division Sub-bituminous byproduct General by-product
(KS standard) Composition Silicon dioxide content unit g Silicon dioxide
content% g Silicon dioxide
content% % Example 1 250 42 750 60 54.5 Example 2 300 40 700 60 53.0 Example 3 350 38 650 60 51.3 Example 4 400 36 600 60 49.4 Example 5 450 34 550 60 47.0

As shown in Tables 1 to 3, the sub-bituminous coal by-product having a low silicon dioxide content and the KS-based fly ash blend composition showed a silicon dioxide content of 45% or more, Can be recycled at low cost.
Therefore, the sub-bituminous by-product preferably has a silicon dioxide content of 34 to 44%.

Paper ash uses limestone powder as a filler to improve paper quality during the paper manufacturing process. At this time, extra limestone fine powder is discharged to the sludge, and it is generated as incineration ash containing calcium oxide in the process of incineration. Calcium oxide reacts with moisture to form calcium hydroxide. At this time, moisture absorption and heat generation can reduce moisture content of the ground.

When the paper ash is used in an amount less than 10% by weight, excess moisture can not be sufficiently absorbed in the case of the ground increase, so that the required strength required for stabilizing the ground can not be secured.

When the paper ash is used in an amount exceeding 15% by weight, the hydration reaction and the pozzolanic reaction do not sufficiently take place due to absorption of moisture required for the hydration reaction of the slag and fly ash, and the ground improvement performance is lowered.

Therefore, the paper ash is preferably used in an amount of 10 to 15% by weight, and the calcium oxide (CaO) contained in a large amount has an effect of reducing the water content, and the role of absorbing, exothermic, and expanding by reacting with water.

The calcium sulfate is used in an amount of 3 to 5% by weight, and when the slag and the alkaline calcium carbonate come in contact with the moisture of the high hydrous soil, the dehydration reaction is caused by the hydration reaction.

When calcium sulfate is used in an amount less than 3% by weight, the effect of accelerating the hydration reaction is insignificant and the effect of dehydration reaction is reduced. When calcium sulfate is used in an amount exceeding 5% by weight, dehydration reaction due to hydration reaction and effect Is not increased any further and it is a cause of cost increase.

Therefore, it is preferable to use 3 to 5% by weight of calcium sulfate.

It is preferable to use a high-strength powder of 4000 cm ² / g or more as calcium sulfate, which increases the specific surface area according to the degree of powder to maximize the reactivity with slag and fly ash, and when using high- The surface hardening performance is improved.

Calcium sulfate can be used as desulfurization gypsum, which is a flue gas desulfurization gypsum produced by neutralizing sulfur dioxide in limestone oil in exhaust gas of natural anhydrous gypsum or thermal power plant.

Flue gas desulfurization gypsum is a gypsum that is pumped from chemical processes, smelters, and thermal power plants. It is produced by neutralizing sulfur dioxide in the exhaust gas with lime oil, and it is a dihydrate of calcium sulfate. It is an industrial by-product produced during the desulfurization process and is less expensive than calcium sulfate and can be used as an alkali accelerator in a high-fire mixture.

Hereinafter, the fire resistant composition for soft ground prepared according to the examples and the comparative examples was applied to the high soil having a wet density of 1.70 g / cm < ² > (no. ³ , the compressive strength and the plate loading test were carried out at the age of 7 days and 28 days.

The specimens were mixed with a high - fire mixture in an electric mixer for 3 minutes, and then specimens were prepared with sufficient compaction in a cylindrical mold having a diameter of 5 cm and a height of 10 cm. The specimens were tested for uniaxial compressive strength by the KS F 2314 method after sealing curing at a temperature of 23 degrees Celsius, and the results are shown in Tables 5 and 6 below, respectively.

The blending ratios of Comparative Examples and Examples are shown in Table 4 and are as follows. The firefighting amount was 150 kg / m ³ for 1000 kg / m ^{3 of} the high functional soil used in the test. The proportion of the fire retardant composition in the examples was 20 wt% for ordinary portland cement, 30 wt% for slag, 30 wt% 15% by weight of paper ash and 5% by weight of calcium sulfate.

The blending ratio for the comparative example and the example division Fire
usage Water cost
soil water cement Slag Fly
Ash A Fly
Ash B restraint
ash Desulfurization
gypsum Sulfuric acid
calcium unit kg / m ³ % kg / m ³ kg / m ³ kg / m ³ kg / m ³ kg / m ³ kg / m ³ kg / m ³ kg / m ³ kg / m ³ Comparative Example 1 150 20 1000 30 150 - - - - - - Comparative Example 2 150 20 1000 30 30 45 - - 22.5 60 - Comparative Example 3 150 20 1000 30 30 45 45 - 22.5 - 7.5 Example 150 20 1000 30 30 45 - 45 22.5 - 7.5

* Fly ash A - Normal fly ash with an SiO ₂ content of 45% or more

* Fly ash B-ash blend containing bituminous by-products

Comparative Example 1 - Common Portland Cement

Comparative Example 2 - Normal Bottle Land cement + fine powder of slag + paper ash + desulfurization plaster

Comparative Example 3 - ordinary Portland cement + slag fine powder + powder fly ash A +

      Paper ash + calcium sulfate

Example - Normal Portland Cement + Slag Powder + Powder Fly Ash B +

      Paper ash + calcium sulfate

Compressive strength test division High Fire Consumption
(kg / m ³ ) Water cost
(%) Compressive strength (MPa) 1 day 3 days 7 days 28th Comparative Example 1 150 20 0.5 0.7 1.3 1.9 Comparative Example 2 150 20 0.5 0.8 1.3 2.0 Comparative Example 3 150 20 0.6 0.9 1.6 2.2 Example 150 20 0.6 0.9 1.5 2.4

As shown in Table 5, in the compressive strength test, as in Comparative Example 2, Comparative Example 3, and Example, in comparison with Comparative Example 1 composed of only portland cement, it is preferable to include fly ash, slag, papermaking ash, calcium sulfate, It was found that the compressive strength was superior to that of Comparative Example 1 composed of only Portland cement, even when calcium sulfate was replaced with a desulfurized gypsum, as in Comparative Example 2, It was confirmed that the use of sub-bituminous by-products as in the examples increases in terms of long-term compressive strength.

Flat plate load test division
standard result Bearing capacity (ton) Settlement (mm) Bearing capacity (ton) Settlement (mm) Comparative Example 1 15 25 22.5 5.0 Comparative Example 2 15 25 25.0 5.0 Comparative Example 3 15 25 24.8 5.1 Example 15 25 24.4 5.2

As shown in Table 6, in the case of the plate load test, both the comparative example and the example satisfy the conditions of the bearing capacity and the settlement amount.

The bearing capacity of Comparative Example 2 was higher than that of Comparative Example 3 using fly ash having an SiO ₂ content of 45% or more.

Therefore, as described above, the formulation using the ash blend containing the sub-bituminous coal by-product was superior to the ordinary blend using the ordinary plain Portland cement in terms of the compressive strength and the plate load test, and the desulfurized gypsum The formulation also showed a similar level to that of ordinary Portland cement.

As described above, the fire retardant composition for soft ground utilizing the sub-bituminous coal by-product of the present invention is produced by mixing sub-bituminous coal by-products, which have a low content of silicon dioxide (SiO ₂ ) generated during the power generation of the power plant CFBC boiler, with fly ash, It is not only economical but also solves the problem of high cost of existing firefighting by using it as material of fire. It is environment that there is no secondary pollution in processing soft soil, river bed bottoms, construction bottoms, inorganic sludge etc. There is a very useful effect that can produce friendly fire.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the above teachings. will be. The invention is not limited by these variations and modifications, but is limited only by the claims appended hereto.

Claims (5)

Usually from 15 to 42% by weight of Portland cement;
25 to 35% by weight of slag;
20 to 40% by weight of bituminous coal by-products having a silicon dioxide content of 34 to 44% and 60 to 80% by weight of fly ash having a silicon dioxide content of 50 to 60% to form an ash blend 20 having a silicon dioxide content of 45% To 30% by weight;
10 to 15% by weight of paper ash;
3 to 5% by weight of calcium sulfate; and a fire-retardant composition for soft ground using sub-bituminous coal by-products. delete The method according to claim 1,
Wherein the bituminous by-product of sub-bituminous coal has a density of 1.0 to 2.0 g / cm ³ and a powder of 1,000 to 5,000 cm ² / g. The method according to claim 1,
Wherein the slag is 4000 to 6000 cm ² / g and the particle size is 12 to 16 μm. The method according to claim 1,
Characterized in that calcium sulfate is a desulfurization gypsum which is a flue gas desulfurization gypsum produced by neutralizing sulfur dioxide in the exhaust gas of a natural anhydrous gypsum or thermal power plant with lime oil.