KR101786901B1 - Backfill Composite Comprising Acid-Treated Waste Oyster Shell And Clay Or Coal Ash, Construction Method Using The Same - Google Patents

Abstract

The present invention relates to a backfill material that achieves high strength while lowering costs through the use of low energy. It uses natural oyster shells that are difficult to dispose of and coal fly ash that has not been recycled but has been landfilled, as a backfill material with improved economic and performance properties. Thereby providing a high-strength backfill without using expensive raw materials such as sand or cement, while contributing to environmental conservation by mass-treating the waste.

Description

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to a backfill material containing sulfuric acid-treated oyster shells and loess or coal fly ash,

The present invention relates to a method for manufacturing a backfill material that achieves high strength while reducing costs through the use of low energy. More specifically, the present invention relates to a method for manufacturing a backfill material which is capable of replacing cement by using waste oyster shell and environment- To a low cost backfill material manufactured by mixing fire and sand with an untreated natural oyster shell and coal fly ash in appropriate proportions, and a construction method using the same.

Typically, the backfill is used to fill the empty space below the building, around the underground pipe, under the road, under the subway, or for the back wall or the wall finish.

Conventionally, such backfill material has been used to discard residues generated during excavation and to purchase new quality sand for compaction. Disposal disposal of the excavated soil and collection of the sand adversely affect the environment, and there are problems such as noise and vibration, difficulty in compaction under the pipe, and compaction efficiency.

In order to solve this problem, fluidized backfill materials have been developed which can be used without any compaction by using excavated soil and without compaction.

Among these, the fluidity backfill material which can be subjected to the compaction treatment can include the self-leveling ability, self-compaction, and anthropogenic intensity control, so that no additional compaction is required, However, since cement and sand are used in large quantities because of the high cost of cement and sand, the cement and sand are consumed in a large amount of energy because they are produced through a melting process at a high temperature, The resulting carbon dioxide emissions are accompanied by environmental problems such as the emission of about 0.9 tons of carbon dioxide each time one ton of cement is produced.

In order to solve this problem, a fluid backfill material using oyster shells without using sand was developed. However, since cement is still used, there are various problems in economical and environmental aspects (Non-Patent Document 1).

Therefore, there is a need to develop a low cost fire extinguisher which can solve the above problems, and which can be replaced with an economical one.

Non-Patent Document 1. Clean Technology, 19, 4, 423-429. 2013

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method of manufacturing a waste oyster and a coal fly ash by mixing waste oyster shell and fly ash with other materials at an appropriate ratio without using cement and sand, , A workability and a compressive strength.

The present invention has been made in view of the above problems, and it is another object of the present invention to provide a method of using the backfill material.

In order to accomplish the above object, the present invention provides a method for producing an oyster shell, comprising: (a-1) 30 to 50 wt% sulfuric acid-treated oyster shell; (a-2) 5 to 30 wt% of any one selected from the group consisting of clay, coal ash, and mixtures thereof; And (a-3) from 30 to 40% by weight of a sodium hydroxide solution;

(b) 5 to 60% by weight natural oyster shell; And

(c) 5 to 60% by weight of coal ash.

The sulfated oyster shell has a CaO content of 40 to 70 wt%, an SO ₃ content of 10 to 50 wt%, an Na ₂ O content of 0 to 10 wt%, a SiO ₂ content of 2 to 3 wt% and an MgO content of 0 to 10 wt% Characterized by containing a chemical component.

The sodium hydroxide solution is characterized by a concentration of 1 to 10 N.

The backfill may further comprise 0.5 to 10% by weight of an additive.

The additive may be at least one selected from the group consisting of a defoaming agent, a retarder, a thickener, a pigment, a crack reducing agent, an antibacterial agent and an expanding agent.

The backfill material compressive strength is characterized in that the compression strength is maintained up to 1 to 30 days if the curing degree of from 3.5 to 28 ㎏ _f / ㎠.

To achieve these and other objects,

(I) treating the natural oyster shell with a sulfuric acid solution to prepare a sulfuric acid treated oyster shell;

II) any one selected from the group consisting of loess, coal fly ash, and mixtures thereof in the sulfated oyster shell of step I); And sodium hydroxide solution to produce a solid fire; And

III) mixing the oyster shell and the fly ash in the fire of step II) to produce a backfill material;

And (iv) placing and curing the backfill material in the step (III).

When curing for 1 to 30 days the backfill material to 3.5 to 28 ㎏ _f / ㎠ it characterized in that the compressive strength is maintained.

According to the present invention, it is possible to use the oyster shell which is difficult to treat and the coal fly ash which has not been recycled but has been buried as a backfill material having economic and performance properties, thereby contributing to environmental conservation by treating the waste in large quantity, The backfill material of excellent strength is provided.

In addition, since the cement is completely replaced by the fire that includes the sulfuric acid-treated oyster shell of the present invention and the fires including the loess, fly ash, or a mixture thereof and sodium hydroxide, a large amount of carbon dioxide generated during the production of the cement can be reduced, And coal ash are recycled, not only the economic burden of securing landfill, but also environmental problems can be solved.

FIG. 1A is a photograph of a specimen completed through a curing process of 20 days after being manufactured from a cigarette of Example 8, FIG. 1B is a photograph of a specimen completed through a curing process of 20 days after being manufactured from the cigarette of Example 9 to be.
FIG. 2 is a photograph of a specimen completed through a 20 day curing process of the backfill material prepared in Examples 14 to 22. FIG.
3 is a process diagram showing a method of applying a backfill according to the present invention.

Hereinafter, various aspects and various embodiments of the present invention will be described in more detail.

One aspect of the present invention is

(a-1) 30 to 50 wt% sulfuric acid-treated oyster shell; (a-2) 5 to 30 wt% of any one selected from the group consisting of clay, coal ash, and mixtures thereof; And (a-3) from 30 to 40% by weight of a sodium hydroxide solution;

(b) 5 to 60% by weight natural oyster shell; And

(c) 5 to 60% by weight of coal ash.

Particularly, (a-1) 30 to 50% by weight of oyster treated oyster shell; (a-2) 5 to 30 wt% of any one selected from the group consisting of clay, coal ash, and mixtures thereof; And (a-3) 30 to 40% by weight of a sodium hydroxide solution; serves as a substitute for common portland cement.

According to the present invention, the oyster farming industry, which accounts for a large portion of exports, the domestic market and the southern coastal economy, realizes an environmentally friendly fire by using natural oyster shells of about 300,000 tons per year.

Of the natural oyster shells, about 150,000 tons are not recycled and are buried or left untreated. In order to solve this problem, some technologies such as fertilizer and oyster grafting have been developed. However, various problems such as quantitative limit of recycling, expensive facility investment cost, complicated process, high energy input and landfill have been pointed out. Therefore, it is urgent to present a new low - cost solution for mass processing of natural oyster shells.

Accordingly, the present invention relates to a process for producing a natural oyster shell, which is a waste, by mixing the oyster shell with a fly ash, a fly ash, or a mixture thereof at a suitable ratio, through a simple acid treatment process without conducting a high- And it is used as a material to replace aggregates. Thus, there is a technical feature that a natural oyster shell is mass-processed through a low-energy process.

(A-1) a sulfuric acid treated oyster shell; (a-2) any one of loess, fly ash, and mixtures thereof; (b) natural oyster shell; And (c) the particle size of the fly ash is all within the range of 10 to 150 mu m, preferably 10 to 120 mu m, and the particle shape thereof is preferably spherical. When these conditions are satisfied, So that the fluidity is increased.

(A-3) sodium hydroxide solution is added to the dried mixed solids in which (a-1) the oyster-treated oyster shell treated with the (a-1) sulfuric acid and (a-2) the loess, the fly ash, To ensure the necessary fluidity and to respond to the follicles needed for solidification. Water may be further added depending on the viscosity of the harsh fire. However, when the excess amount of water is added at this time, the strength is reduced rather than the amount. Therefore, it is important to add an appropriate amount depending on the intended use.

The (a-1) sulfuric acid-treated oyster shell was prepared by treating natural oyster shell with sulfuric acid solution, and CaCO _{3, which} is a main component of the natural oyster shell, was converted into CaSO ₄ through the treatment with sulfuric acid as shown in the following chemical reaction formula 1 Resulting in a sulfuric acid-treated oyster shell as a main component.

[Chemical reaction formula 1]

CaCO ₃ (S) + H ₂ SO ₄ (aq) → CaSO ₄ (S) + H ₂ O (aq) + CO ₂ ↑

Specifically, the concentration of the sulfuric acid solution used for sulfuric acid treatment of the natural oyster shell may be 1 to 10 N (normal concentration), preferably 5 to 10 N.

In particular wherein the chemical composition measurements by implementing the XRF analysis of the sulfuric acid-treated oyster shell is 40 to 70% by weight CaO content, SO ₃ content of 10 to 50 wt%, Na ₂ O content of from 0 to 10 wt%, SiO ₂ content of from 2 to 3 By weight and an MgO content of 0 to 10% by weight, and preferably the X-ray analysis of the sulfuric acid treated oyster shell is carried out, wherein the measured chemical components are CaO content 40 to 65% by weight, SO ₃ content 30 to 50% , Na ₂ O content of 0 wt%, SiO ₂ content of 2 to 3 may be in% by weight and MgO content 0 to 10% by weight, the compressive strength of the final finished specimens 3.5 ㎏ _f / ㎠, up to 50 ㎏ _f / ㎠ In order to satisfy the above range, it is necessary to use a material having a CaO content of 40 to 65% by weight, an SO ₃ content of 30 to 50% by weight, and no by-products such as Na ₂ O.

Generally, since natural oyster shell is mainly composed of CaCO ₃ , it is essential to convert it to CaO through firing at a high temperature of 800 to 1200 ° C. for a long time. Using the natural oyster shell with this process, there are environmental and economic problems such as high energy consumption and excessive carbon dioxide emission.

Therefore, in the present invention, in order to overcome such a problem and overcome this problem, the existing high temperature firing process is replaced with the sulfuric acid treatment process in order to process the natural oyster shell, thereby significantly reducing the process cost through energy saving.

On the other hand, coal fly ash is coal ash discharged from the combustion boiler at 1400 ℃ in the combustion boiler such as coal-fired power plant which uses pulverized coal as fuel. 60% of the coal fly ash is generated from coal fly ash as 60% % Are buried, it is required to develop a technique for processing the same.

Researches have been conducted in various fields to develop a method capable of mass-treating waste oyster shells and coal ash causing the above-mentioned environmental pollution problem. However, in order to consume a large amount of oyster shell, a high temperature (800 to 1200 ° C) A process of converting into a slaked lime form is required, and there is a problem that a high energy cost and a large plant construction cost are generated. The present invention, however, has the advantage of being able to handle large amounts of oyster shells and fly ash, albeit with much lower energy costs.

According to one embodiment of the present invention, the dry mixed solids in which (a-1) the oyster treated oyster shell and (a-2) the loess, the fly ash, When the sodium solution is added, the oyster-treated oyster shell and the sodium hydroxide solution react with each other as shown in the following chemical reaction formula 2 to generate hydrated lime and then react with silica (SiO ₂ ) or alumina (Al ₂ O ₃ ) 3, and 4, respectively.

[Chemical reaction formula 2]

(Aq) Ca ₂ SO ₄ (ag) + Ca (OH) ₂ (aq) CaSO ₄ (S) + ₂ NaOH

[Chemical reaction formula 3]

_{3Ca (OH) 2 + 2SiO 2} → 3CaO · 2SiO 2 · 3H 2 O

[Chemical reaction formula 4]

_{3Ca (OH) 2 + Al 2} O 3 → 3CaO · Al 2 O 3 · 3H 2 O

The phosylan reaction is a reaction in which solutes such as silica and alumina contained in yellow soil are formed by Ca (OH) ₂ produced from the oily treated oyster and the insoluble compound through the chemical reaction formula 2 to solidify.

In the present invention, it is possible to produce a fireproofing material having a sufficient compressive strength through solidification by the above-mentioned Foilan reaction, and by using natural oyster shells and coal fly ashes which are not treated with waste as an aggregate, , And thus completed the backfill material having excellent flowability and strength.

And may be any one selected from the group consisting of (a-2) loess, fly ash, and mixtures thereof. Preferably, only coal fly ash or only yellow loess may be added, or a mixture of fly ash and loess may be added, Only yellow soil is added. Because the compressive strength of the final finished specimens according ocher inducing Four jeulran response to the input tray to supply a sufficient amount of silica and alumina because it can achieve more than 50 ㎏ _f / ㎠. When the fire has a high strength, it is possible to increase the addition amount of natural oyster shell and fly ash as substitute materials of aggregate while minimizing the addition amount of the firefly within the range of satisfying the compressive strength range of the finished backfill, The coal fly ash can be mass-processed with low energy.

More specifically, the solidifying is one can be used if the compressive strength is more than 9 ㎏ _f / ㎠, in order to achieve this, the high-fire (a-1) the sulfate process oyster shell 30 to 50% by weight; And (a-2) 5 to 30 wt% of any one selected from the group consisting of clay, coal ash, and mixtures thereof; And (a-3) from 30 to 40% by weight of a sodium hydroxide solution. However, when the (a-1) sulfuric acid-treated oyster shell is less than 30% by weight, the compressive strength of the harsh fire rapidly decreases to 1.5 kgf / cm 2.

Preferably, the high compressive strength of the fire is there be at least 10 ㎏ _f / ㎠, in order to achieve this (a-1) the sulfate process oyster shell 40 to 50% by weight; And (a-2) 10 to 30 wt% of any one selected from the group consisting of clay, coal ash, and mixtures thereof; And (a-3) 30 to 40% by weight of a sodium hydroxide solution. If the (a-1) sulfuric acid-treated oyster shell is blended at less than 40% by weight, there arises a problem that not only the initial strength but also the long-term strength is lowered. If the oyster shell is added in an amount exceeding 50% by weight, of CaSO ₄ and fly ash or silica provided from yellow soil (SiO ₂₎ and alumina (Al ₂ O ₃₎ does not match the ratio between, may cause problems that the compression strength is considerably lowered.

If the content of any one selected from the group consisting of (a-2) clay, coal ash and mixtures thereof is less than 10% by weight, the initial strength is significantly lowered, The content of the sulfuric acid-treated oyster shell is relatively decreased, so that there is a possibility that the intensity manifestation greatly varies depending on the kind of the target soil.

When the sodium hydroxide solution (a-3) is added in an amount of less than 30% by weight, the reaction rate with the sulfuric acid-treated oyster shell may decrease, resulting in a problem of not uniformly solidifying. The reaction rate with the sulfuric acid-treated oyster shell is rapidly increased, and excessive sodium ions are present to inhibit the fosilan reaction, so that the compressive strength may be lowered, or the period for curing may be excessively prolonged .

And in accordance with the present invention a fire is most preferably the best 50 ㎏ _f / ㎠ as long as it has a more compressive strength, in the range satisfying the backfill material compressive strength required value (3.5 to 7 ㎏ _f / ㎠), the minimum amount to the backfill material (A-1) from 40 to 50% by weight of the sulfuric acid-treated oyster shell; and (c) from the total amount of the oyster shell and the fly ash. And (a-2) from 10 to 30% by weight of loess; And (a-3) from 30 to 40% by weight of a sodium hydroxide solution.

The sodium hydroxide solution (a-3) may be used in a concentration of 1 to 20 N in the solidification according to the present invention, and preferably the sodium hydroxide solution having a compressive strength of 1 N It is preferred to use a 5 to 15 N sodium hydroxide solution which is 11 to 15 times better than the solid fire. If sodium hydroxide solution is used at a concentration exceeding 20 N, excessive sodium ion inhibits the reaction of the phosgene, so that the compression strength of the final finished backfill including such a fire may be lowered, And the like.

The natural oyster shell (b) is in the form of a powder which is washed, dried and then pulverized, and unlike the sulfuric acid-treated oyster shell used for the fire, nothing is treated. Generally, sand, gravel and soil are used as natural backfill materials. Such natural aggregates have been rapidly depleted due to rapid increase in construction volume due to domestic economic growth. However, in order to prevent destruction of marine ecosystem due to deforestation and marine harvesting due to the development of seismic development, there is a need for strict Due to environmental regulations, difficulties are growing in the production and supply of aggregates, and it is urgent to develop materials that can be used alternatively.

In the present invention, natural oyster shells and fly ash are used as an aggregate replacement material in order to solve such problems, and the excellent strength and fluidity of the backfill are maintained, while the natural oyster shells and fly ash as waste are mass- Thereby achieving the effect of preventing the rise.

The backfill according to the present invention may further comprise 0.5 to 10% by weight of an additive selected from the group consisting of a defoaming agent, a retarding agent, a thickener, a pigment, a crack reducing agent, an antimicrobial agent and an expanding agent Or more.

The antifoaming agent is used to remove the pores in the backfill to increase the strength and durability of the backfill. It is used in a wide variety of applications such as mineral oil defoaming agents such as kerosene and paraffin, preservative antifoaming agents such as animal and vegetable oils, sesame oil and pharmacy oils, oleoresins, Fatty acid type antifoaming agents such as alkylene oxide adducts thereof, alcohol type antifoaming agents such as octyl alcohol, hexadecyl alcohol, acetylenic alcohol and glycols, metal soap type antifoaming agents such as calcium oleate, dimethyl silicone oil, silicone emulsion, And silicone-based antifoaming agents such as polysiloxane (polyorganosiloxane such as dimethylpolysiloxane). However, in the present invention, a mineral oil-based defoaming agent having excellent safety and excellent effects can be used.

The retarder is used for the purpose of suppressing rapid curing of the backfill material, and may be a water reducing agent for cement or concrete or a hydration retardant for cement.

The thickener may be any one selected from the group consisting of a polyacrylamide-based water-soluble polymer, polyvinyl alcohol, polyvinyl acetate and a cellulose-based thickener, which is added to improve the viscosity and flocculation action of the backfill.

The pigment may be a conventionally used pigment. As the inorganic pigment, any one or more selected from the group consisting of red iron oxide, yellow iron oxide, chromium oxide, titanium dioxide and carbon black may be used. The backfill material may have various colors such as red, green, yellow, black, blue, and white.

In addition, the backfill according to the present invention may further include at least one additive selected from a crack reducing agent, an antibacterial agent and an expanding agent depending on the use or place of use.

The backfill material compressive strength of the above-described configuration, there is a compression strength may be maintained from 1 to 30 days if the curing degree of from 3.5 to 30 ㎏ _f / ㎠ which is to satisfy the compressive strength range general backfill material.

Another aspect of the invention relates to a method of constructing a backfill material comprising the steps of:

(I) treating the natural oyster shell with a sulfuric acid solution to prepare a sulfuric acid treated oyster shell;

II) any one selected from the group consisting of loess, coal fly ash, and mixtures thereof in the sulfated oyster shell of step I); And sodium hydroxide solution to produce a solid fire; And

III) mixing the natural oyster shell and the fly ash in the fire of step II) to produce a backfill material;

And (iv) placing and curing the backfill material in the step (III).

FIG. 3 is a process drawing showing a method of constructing a backfill according to the present invention, and will be described in detail below with reference to the same.

First, the natural oyster shell is treated with a sulfuric acid solution to produce a sulfuric acid-treated oyster shell. Specifically, the natural oyster shell is a natural oyster shell without any treatment (FIG. 3, I).

The natural oyster shell may be washed, dried and then pulverized before the sulfuric acid treatment, and then the crushed oyster shell is put into a sorter to select a particle size in the range of 10 to 150 mu m.

The natural oyster shell is treated with a sulfuric acid solution.

Through the process of treating the natural oyster shell with a sulfuric acid solution, CaCO _{3, which} is the main component of the natural oyster shell, is converted into CaSO ₄ through the treatment with sulfuric acid as shown in the following chemical reaction formula 1, and a sulfuric acid- .

[Chemical reaction formula 1]

CaCO ₃ (S) + H ₂ SO ₄ (aq) → CaSO ₄ (S) + H ₂ O (aq) + CO ₂ ↑

The concentration of the sulfuric acid solution may be 1 to 10 N, preferably 5 to 10 N. As the concentration of sulfuric acid increases from 1 N to 10 N, the conversion of CaCO ₃ to CaSO ₄ is increased Can be confirmed through an experimental example to be described later. However, when the concentration of the sulfuric acid solution is 10 N or more, the conversion rate is gentle, and therefore, the preferable concentration of the sulfuric acid solution is 1 to 10 N.

Most preferably, the concentration of the sulfuric acid solution may be between 5 and 10 N, since 1 N is present at a ratio of about 7: 1 of the chemical composition of SO ₃ rather than the chemical composition of CaO, thus ensuring a sufficient amount of CaSO ₄ And by-products such as Na ₂ O are present. As will be described later, when the oyster shell treated with 1 N sulfuric acid solution is mixed with coal fly ash, the oyster shell treated with 10 N sulfuric acid solution is about 4 times lower than that of the fly ash mixed with coal fly ash.

However, the oyster shell treated with sulfuric acid solution of 5 to 10 N concentration can be appropriately selected depending on the application. Oyster shell treated with sulfuric acid solution of 5 to 7 N concentration has a chemical composition of SO ₃ of about 6 : 3, and there is no chemical component of MgO that affects long-term expandability that can prevent splitting due to shrinkage, so that the long-term expandability is weak, but the initial strength is treated with a 10 N sulfuric acid solution It is advantageous that the oyster shell is twice as much as the specimen prepared by mixing with fly ash.

On the other hand, the oyster shell treated with a sulfuric acid solution having a concentration of 8 to 10 N has a chemical composition ratio of CaO and SO ₃ of 1: 1 and MgO chemical composition of 5 to 10% by weight even when there is no by-product such as Na ₂ O The initial strength is relatively lower than the specimens prepared by mixing the oyster shell treated with the sulfuric acid solution having the concentration of 5 to 7 N and the fly ash, but the long-term expansibility can be ensured.

Oyster shells treated at a high temperature of 800 to 1200 ° C for a long period of time have environmental and economic problems such as high energy consumption during production and excessive carbon dioxide emission. In the present invention, in order to overcome such a problem and to overcome this problem, as described above, the natural oyster shell is treated with sulfuric acid to reduce the energy consumption, thereby lowering the processing cost.

The method may further include a step of recovering the sulfuric acid-treated oyster shell prepared in step (I) and then performing hot air drying before step (II).

The mixture of the loess and coal fly ash may be mixed in a weight ratio of 1-5: 1.

Thereafter, in step II), the oyster treated oyster shell of step I), and any one selected from the group consisting of loess, fly ash, and a mixture thereof, and a sodium hydroxide solution are mixed to produce a fire (FIG. 3, The step of manufacturing fire).

Specifically, when the sodium hydroxide solution is added to the dry mixed solids in which the oyster-treated oyster shell treated with the sulfuric acid, the fly ash, and the mixture thereof is mixed, the step (II) The sodium solution reacts to produce slaked lime and then solidified through the fodder reaction of the chemical formulas 3 and 4 with silica (SiO ₂ ) or alumina (Al ₂ O ₃ ) provided from the fly ash or loess.

[Chemical reaction formula 2]

(Aq) Ca ₂ SO ₄ (ag) + Ca (OH) ₂ (aq) CaSO ₄ (S) + ₂ NaOH

[Chemical reaction formula 3]

_{3Ca (OH) 2 + 2SiO 2} → 3CaO · 2SiO 2 · 3H 2 O

[Chemical reaction formula 4]

_{3Ca (OH) 2 + Al 2} O 3 → 3CaO · Al 2 O 3 · 3H 2 O

And the fire may be less than the compressive strength of the specimens over 1 ㎏ _f / ㎠ produced through curing preferably 10 ㎏ _f / ㎠ or higher, more preferably 50 ㎏ _f / ㎠. This is because the lower the compressive strength of the harsh fire is, the more the addition amount of the harsh fire must be increased and the addition amount of the aggregate is lowered. That is, the higher the compressive strength of the fireproofing material, the more excellent the strength can be secured even if a minimum amount of the fireproofing material is added, and the amount of the aggregate material is increased, so that the natural oyster shell and the flyash as waste can be mass-processed. Thus 1 ㎏ _f / ㎠ and more having a compressive strength by using the fire can also be made a backfill material of high strength. However, 10 ㎏ _f / ㎠ or more, more preferably 50 ㎏ _f to the bulk processing of natural oyster shell and fly ash / Cm < 2 > or more.

When using the high to achieve at least 50 ㎏ _f / ㎠ compressive strength of the fire as an example, the high and the fire can be minimized up to 20 to 30% by weight, aggregate substitute material composed of any one of natural oyster shell and the fly ash is 50 wt. for up it added to%, and backfill material compressive strength of such a configuration it is possible to achieve more than 3.5 ㎏ _f / ㎠, as well as to achieve flexibility and compressive strength while minimizing the cost of the process while using low-energy natural Oyster shells and fly ash can be mass-processed.

More specifically, in which the fire has a compressive strength 9 ㎏ _f / ㎠ not less than using a single available, in which the fire is an oyster shell 30 to 50% by weight sulfuric acid treatment in order to achieve this; And 5 to 30 wt% of any one selected from the group consisting of clay, coal ash, and mixtures thereof; And 30 to 40 wt% sodium hydroxide solution. However, if the oyster treated oyster shell is less than 30 wt%, the compressive strength of the harsh fire is drastically lowered to 1.5 kgf / cm 2.

In order to achieve the high compressive strength of the fire over 10 ㎏ _f / ㎠ treated oyster shell sulfuric acid 40 to 50% by weight; And 10 to 30 wt.% Of any one selected from the group consisting of clay, coal ash, and mixtures thereof; And 30 to 40% by weight of a sodium hydroxide solution.

If the sulfuric acid treated oyster shell is blended at less than 40 wt%, the initial strength as well as the long-term strength are lowered. If the oyster shell is added in an amount exceeding 50 wt%, oxalic acid-treated oyster shell, CaSO ₄ , Or the ratio of silica (SiO ₂ ) and alumina (Al ₂ O ₃ ) provided from the loess is not matched, so that there is a problem that the compressive strength is significantly lowered.

If the content of any one selected from the group consisting of clay, coal ash and mixtures thereof is less than 10% by weight, there is a problem that the initial strength is significantly lowered. When the content exceeds 30% by weight, Since the content of sulfuric acid treated oyster shells is relatively reduced, there is a possibility that the intensity manifestation fluctuates greatly depending on the kind of the target soil.

If the sodium hydroxide solution is added in an amount of less than 30% by weight, the rate of reaction with the sulfuric acid-treated oyster shell may decrease, resulting in a problem of not being solidified uniformly. If the sodium hydroxide solution is added in an amount exceeding 40% by weight, And the excessive sodium ion is present to inhibit the phosgene reaction, so that the compressive strength may be lowered, or the period required for curing may be excessively long.

In other words, the fireproofing according to the present invention comprises 40 to 50% by weight of the sulfuric acid treated oyster shell; And 10 to 30% by weight of loess; And a solution of sodium hydroxide of 30 to 40% by weight; together is most desirable to mix in is because to obtain the most superior than 50 ㎏ _f / ㎠ compressive strength.

As will be described later in the Experimental Example, the sodium hydroxide solution concentration can be used in the range of 1 to 20 N in the fire according to the present invention, and preferably the compression strength is eleven times greater than the specimen prepared by treating with 1 N sodium hydroxide solution To 15 times better, 5 to 15 N sodium hydroxide solution is preferably used. If sodium hydroxide solution having a concentration exceeding 20 N is used, the excessive sodium ion inhibits the fosilan reaction. Therefore, the compression strength of the backfill made using the above-mentioned fire is lowered, and the period required for curing A problem such as excessively lengthening may occur.

Next, in step III), the natural oyster shell and the fly ash as an aggregate replacement material are mixed with the fire in the step II) to produce a backfill material (FIG. 3, step III).

In the production of the backfill according to the present invention, there is no particular limitation on the method of adding and mixing the firefly, but the general method of mixing the components is most widely used, and homogeneous mixing is most important.

The backfill according to the present invention produces each raw material and allows it to be mixed with a general consumer or a construction site. However, the backfill of the present invention can be applied to the natural oyster shell and the fly ash, It is preferable to inject it.

For the compressive strength material the backfill to satisfy the range from 3.5 to 7 ㎏ _f / ㎠, the high is the compressive strength of the fire from 1 to 49 ㎏ _f / ㎠ range of the high fire can be mixed from 50 to 80% by weight, in which the the compressive strength of the fire is more than 50 ㎏ _f / ㎠ range and the fire can be minimized up to 20 to 30% by weight, the aggregate substitute material of natural oyster shell and coal ash is the maximum amount may be mixed.

It can also be adjusted as appropriate amount of the mixture ratio of the material backfill composition to control the compressive strength from 3.5 ㎏ _f / ㎠ to 28 ㎏ _f / ㎠.

The backfill material comprises (a) 20 to 80% by weight of a solid fire; (b) 5 to 60% by weight natural oyster shell; And (c) 5 to 60% by weight of coal ash. As mentioned above, by controlling the mixing ratio of the (a) firefly, (b) natural oyster shell, and (c) coal fly ash it is possible to control the compressive strength at 3.5 ㎏ _f / ㎠ to 28 ㎏ _f / ㎠.

The backfill may further include 0.5 to 10% by weight of an additive. The additive may be at least one selected from the group consisting of a defoaming agent, a retarder, a thickener, a pigment, a crack reducing agent, an antimicrobial agent and an expanding agent have.

The antifoaming agent is used to remove the pores in the backfill to increase the strength and durability of the backfill. It is used in a wide variety of applications such as mineral oil defoaming agents such as kerosene and paraffin, preservative antifoaming agents such as animal and vegetable oils, sesame oil and pharmacy oils, oleoresins, Fatty acid type antifoaming agents such as alkylene oxide adducts thereof, alcohol type antifoaming agents such as octyl alcohol, hexadecyl alcohol, acetylenic alcohol and glycols, metal soap type antifoaming agents such as calcium oleate, dimethyl silicone oil, silicone emulsion, And silicone-based antifoaming agents such as polysiloxane (polyorganosiloxane such as dimethylpolysiloxane). However, in the present invention, a mineral oil-based defoaming agent having excellent safety and excellent effects can be used.

The retarder is used for the purpose of suppressing rapid curing of the backfill material, and may be a water reducing agent for cement or concrete or a hydration retardant for cement.

The thickener may be any one selected from the group consisting of a polyacrylamide-based water-soluble polymer, polyvinyl alcohol, polyvinyl acetate and a cellulose-based thickener, which is added to improve the viscosity and flocculation action of the backfill.

The pigment may be a conventionally used pigment. As the inorganic pigment, any one or more selected from the group consisting of red iron oxide, yellow iron oxide, chromium oxide, titanium dioxide and carbon black may be used. The backfill material may have various colors such as red, green, yellow, black, blue, and white.

In addition, the backfill according to the present invention may further include at least one additive selected from a crack reducing agent, an antibacterial agent and an expanding agent depending on the use or place of use.

The present invention is based on the fact that the steps I), II), III) and IV) are carried out in a continuous process, wherein steps II) and III) are carried out continuously in the same reactor (see the second reactor of FIG. 3) , And can be mixed and performed simultaneously.

That is, when the oyster treated sulfuric acid solution, the sodium hydroxide solution and the yellow loess are mixed in one reactor, the natural oyster shell and the fly ash may be mixed at the same time to produce a fire and simultaneously produce a backfill material.

Most preferably, however, step (II) and step (III) may be carried out continuously in the same reactor, since the hydration reaction and the phosgene reaction do not affect each other and proceed separately, This is because the backfill can be manufactured.

FIG. 1 is a photograph of a specimen completed through a 20-day curing process produced from the fire in Example 9, wherein all of the specimens prepared from the two embodiments (Examples 8 and 9) are maintained at high strength without cracking Can be confirmed.

Hereinafter, the present invention will be described in more detail with reference to examples, but the scope and content of the present invention can not be construed to be limited or limited by the following examples and the like. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the present invention as set forth in the following claims. It is natural that it belongs to the claims.

In addition, the experimental results presented below only show representative experimental results of the embodiments and the comparative examples, and the respective effects of various embodiments of the present invention which are not explicitly described below will be specifically described in the corresponding part.

Manufacturing example  1 to 3. Sulfuric acid-treated Oyster shell

The natural oyster shell was obtained from Haegang, Gyeongnam, Tongyoung, and dried at 90 ℃. The natural oyster shell was crushed and passed through 125 mesh or less of crushed natural oyster shell to produce natural oyster shell powder. 600 g of the natural oyster shell powder and 900 g of 1 to 10 N sulfuric acid were mixed and allowed to react for 12 hours and then recovered through filtration and dried in a drying oven at 90 ° C to prepare oyster powder treated with sulfuric acid.

The specific mixing ratio and the weight of the finally obtained sulfuric acid-treated oyster shell powder are summarized in Table 1.

Sulfuric acid solution concentration (N) The weight (g) of the finally obtained sulfuric acid treated oyster shell powder Production Example 1 One 566 Production Example 2 5 619 Production Example 3 10 715

As shown in Table 1, represent the difference in handling of sulfuric acid before and after natural oyster shell weight, which as by treatment of the natural oyster shell with sulfuric acid, the CaCO which was a main component of the natural oyster shell ₃ as shown in chemical equation 1, converted into CaSO _4, it Which means that the oyster-treated oyster shell as the main component is being produced.

[Chemical reaction formula 1]

CaCO ₃ (S) + H ₂ SO ₄ (aq) → CaSO ₄ (S) + H ₂ O (aq) + CO ₂ ↑

Manufacturing example  4. Coal fly ash (coal ash)

The coal ash collected from the fly ash landfill at Samcheonpo Thermal Power Plant, Gyeongnam Samcheonpo Thermal Power Plant was dried at 90 ℃ for 12 hours and filtered through 125 mesh.

Manufacturing example  5. Yellow soil

Clay was collected from Kyungnam Sancheong, dried at 90 ℃ for 12 hours and passed through 125 mesh.

Example  1 to 13. Only in the fire  Manufactured Specification  Produce.

The oyster treated oyster shell prepared in Preparation Examples 1 to 3, the fly ash prepared in Preparation Example 4 and the yellow loess prepared in Preparation Example 5 were added to the sodium hydroxide solution, stirred using a high speed stirrer, A cylindrical specimen with a diameter of 5 ㎝ and a surface area of 19.6 ㎠ was prepared by curing in a water bath for 20 days.

At this time, the mixing weight percent of the fly ash, the oyster treated with sulfuric acid, the yellow soil and the sodium hydroxide is shown in Table 2 below.

Sulfuric acid oyster shell Coal fly ash
(weight%) ocher
(weight%) Sodium hydroxide solution sample weight% Concentration (N) weight% Example 1 Production Example 1 31 31 - One 38 Example 2 Production Example 1 31 31 - 10 38 Example 3 Production Example 2 31 31 - One 38 Example 4 Production Example 2 31 31 - 5 38 Example 5 Production Example 2 31 31 - 10 38 Example 6 Production Example 2 31 31 - 15 38 Example 7 Production Example 2 15 47 - 15 38 Example 8 Production Example 2 47 15 - 15 38 Example 9 Production Example 2 47 - 15 15 38 Example 10 Production Example 2 47 7.5 7.5 15 38 Example 11 Production Example 2 31 31 - 20 38 Example 12 Production Example 3 31 31 - One 38 Example 13 Production Example 3 31 31 - 10 38

Example  14-22. Backfill  ≪ RTI ID = Specification  Produce.

The natural oyster shell and fly ash were added as agglomerates to the firefighting material prepared in Example 9, stirred using a high speed stirrer, and then placed in a mold and cured in a water bath at 20 ° C for 20 days to prepare a cylindrical specimen having a surface area of 19.6 cm .

The weight percentages of the fly ash, natural oyster shell, and solid fire are shown in Table 3 below.

Fire aggregate Oyster treated oyster shell (47% by weight): loess (17% by weight): sodium hydroxide solution (38% by weight) Natural oyster shell (% by weight) Fly Ash (% by weight) Example 14 25 18.8 56.2 Example 15 25 37.5 37.5 Example 16 25 56.2 18.8 Example 17 50 12.5 37.5 Example 18 50 25 25 Example 19 50 37.5 12.5 Example 20 75 6.2 18.8 Example 21 75 12.5 12.5 Example 22 75 18.8 6.2

Experimental Example  1. Sulfuric acid treated Oyster  Component analysis

In order to confirm the conversion rate and chemical composition of the sulfuric acid-treated oyster shells according to the sulfuric acid concentration, the sulfuric acid-treated oyster shells prepared in Preparation Examples 1 to 3 and the components of the natural oyster shells without any treatment were subjected to XRF analysis to measure chemical components . The results are shown in Table 4 below.

 Chemical composition analysis of sulfuric acid treated oyster shell (% by weight) ingredient Production Example 1 Production Example 2 Production Example 3 Natural oyster shell CaO 72.9 62.1 45.5 75.7 SO ₃ 10.1 31.4 41.5 0.8 Na ₂ O 7.8 - - 13.3 SiO ₂ 2.7 2.4 2.3 3.1 MgO 3.1 - 6.2 2.5

According to the results of Table 4 analyzes the chemical composition, the increase in SO ₃ is because it indicates that the SO ₃ group is bonded to CaO as a main component was the CaCO ₃ in the natural oyster shell converted into CaSO _4, the concentration of sulfuric acid at 1 N 10 N , The conversion of CaCO ₃ to CaSO ₄ is increased. However, when the concentration of the sulfuric acid solution is 10 N or more, it is found that the conversion rate is gentle, so that the preferable concentration of the sulfuric acid solution is 1 to 10 N.

Most preferably, the concentration of the sulfuric acid solution may be between 5 and 10 N, since 1 N is present at a ratio of about 7: 1 of the chemical composition of SO ₃ rather than the chemical composition of CaO, thus ensuring a sufficient amount of CaSO ₄ And by-products such as Na ₂ O are present. As will be described later, when an oyster shell treated with a 1 N sulfuric acid solution (Preparation Example 1) is mixed with coal fly ash to prepare a specimen, an oyster shell treated with a 10 N sulfuric acid solution (Preparation Example 3) Which is about four times lower than that of

However, from 5 to 10 in the oyster shell treated with a sulfuric acid solution of the N concentration may be properly selected in accordance with Where Used 5 to 7 the oyster shell treated with a sulfuric acid solution of the N concentration (Preparation 2) SO more chemical components of CaO ₃ The chemical composition is present at a ratio of about 6: 3, and the long-term expansibility is weak due to the absence of the chemical component of MgO which affects the long-term expandability which can prevent the decomposition by shrinkage. However, It is advantageous that the oyster shell treated with sulfuric acid solution is about twice as much as the specimen prepared by mixing with fly ash.

The 8 to 10 N with oyster shell treated with a sulfuric acid solution having a concentration of (Production Example 3) by-product is even CaO and the first chemical composition ratio of SO ₃ is not present, such as Na ₂ O: exists as a 1, MgO chemical ingredients 5 To 10% by weight, and the initial strength is relatively lower than that of the specimen prepared by mixing the oyster shell treated with the sulfuric acid solution having the concentration of 5 to 7 N and the fly ash, but the long-term expansibility can be ensured.

Experimental Example  2. Only in the fire  Manufactured Specimen  Comparison of compressive strength (1)

The compressive strengths of the specimens prepared from Examples 6 to 10 were measured and shown in Table 5 below.

The compressive strength test was carried out using the uniaxial compressive strength standard test method (the rate of deformation at a rate of 1.0 mm / min (min) per minute) using a compressive strength test analyzer (300 KN-LVDT 1000 mm, Donga, Busan, Korea) ≪ / RTI >

Compressive strength
(㎏ _f / ㎠) Example 6 9.3 ± 0.5 Example 7 1.5 ± 0.5 Example 8 13.0 ± 1.2 Example 9 53.3 ± 1.3 Example 10 12.3 ± 2.7

As shown in Table 5, Examples 6 to 10 uniaxial compare the compressive strength of the specimens When, in the case to prepare a specimen of only smoke, ash, or contain only loess or ocher and coal ash is be added at the same time more than 10 ㎏ _f / ㎠ excellent or it represents the intensity, if only the yellow soil addition were identified prepared a specimen having at least 50 ㎏ _f / ㎠ remarkably excellent strength.

Experimental Example  3. Only in the fire  Manufactured Specimen  Comparison of compressive strength (2)

In order to confirm the influence of the concentration or the mixing ratio of the sodium hydroxide solution on the compressive strength, the compressive strengths of the specimens prepared from Examples 1 to 6 and 11 to 13 are shown in Table 6 below Specifically, Table 6 shows relatively the compressive strengths of the specimens of Examples 2-6 and 11-13 on the basis of the compressive strength of the specimens of Example 1.

The compressive strength test was carried out using the uniaxial compressive strength standard test method (the rate of deformation was 1.0 mm / min (min) per minute) using a compressive strength test analyzer (300 KN-LVDT 1000 mm, Donga, Busan, Korea) ≪ / RTI >

Relative compressive strength
(Based on Example 1) Example 1 One Example 2 6 Example 3 2 Example 4 8 Example 5 11 Example 6 15 Example 11 8 Example 12 4 Example 13 8

As shown in Table 6, when the compressive strengths of Examples 1-6 and 11-13 were compared, it was found that the specimens prepared using sodium hydroxide solution having a concentration of 10 N and 15 N had the most compressive strength It was confirmed that 10 to 15 N sodium hydroxide solution was the most preferable.

Among them, however, it was confirmed that, as in Examples 5 and 6, when the oyster treated with oily acid was treated with sulfuric acid concentration of 5 to 10 N, it had a strength of 11 to 15 times better than that of Example 1.

That is, when only the sodium hydroxide solution is adjusted to 10 to 15 N, only the strength of 6-8 times higher than that of Example 1 can be obtained. However, if the concentration of the sodium hydroxide solution is controlled to 10 to 15 N simultaneously with the preparation conditions of the sulfuric acid- It can be seen that the strength is 11 to 15 times better than that of the first embodiment.

1 is a photograph of the specimen completed through the 20 days curing process of the fireproof fabric manufactured from Examples 8 and 9, FIG. 1A is a photograph of Example 8, FIG. 1B is a photograph of Example 9 . It can be seen from FIG. 1 that all of the specimens manufactured from the two embodiments (Examples 8 and 9) are maintained at high strength without cracking.

Experimental Example  4. Backfill  Manufactured using Specification  Produce.

The uniaxial compressive strengths of the specimens prepared using the backfill materials prepared in Examples 14 to 22 were measured by a uniaxial compressive strength standard test method (modified by a compressive strength test analyzer (300 KN-LVDT 1000 mm, Donga, Busan, Korea) Measured at a speed of 1.0 mm / minute (min) per minute, with the mold removed).

Compressive strength
(㎏ _f / ㎠) Example 14 3.9 ± 0.1 Example 15 4.4 ± 0.6 Example 16 9.6 ± 1.0 Example 17 7.9 ± 1.0 Example 18 17.6 ± 10.7 Example 19 20.3 + - 6.4 Example 20 23.8 ± 3.1 Example 21 24.3 ± 2.3 Example 22 27.3 ± 1.4

As shown in Table 7, Examples 14 to 22 of the specimens were found to be compressive strength are both 3.5 ㎏ _f / ㎠ or more. Since the general criteria of the compressive strength required for use as backfill material is 3.5 to 7 ㎏ _f / ㎠, exemplary specimens of Examples 14 to 22 according to the present invention may both satisfy this requirement, can be used as backfill material.

In addition, among the specimens of Examples 14 to 22 according to the present invention, the specimens of Examples 14 to 16 contain at least 25% by weight of the fire retardant, while the natural oyster shell and fly ash waste are each 10 to 60% it can be seen that this has the great advantage that it can provide a compression strength of 3.5 to 7 ㎏ _f / ㎠ a satisfactory and that the check bar, after the excellent strength of the waste which has been a problem of environmentally yet high throughput fill material at a low cost .

FIG. 2 is a photograph of the specimen completed through the 20 days curing process of the backfill material prepared in Examples 14 to 22, and it can be confirmed that it is maintained at a high strength without cracking as shown in FIG.

Claims (7)

(a-1) 30 to 50 wt% sulfuric acid-treated oyster shell; (a-2) 5 to 30 wt% of any one selected from the group consisting of clay, coal ash, and mixtures thereof; And (a-3) from 30 to 40% by weight of a sodium hydroxide solution;
(b) 5 to 60% by weight natural oyster shell; And
(c) 5 to 60% by weight of coal ash,
The sulfated oyster shell has a CaO content of 40 to 70 wt%, an SO ₃ content of 10 to 50 wt%, an Na ₂ O content of 0 to 10 wt%, a SiO ₂ content of 2 to 3 wt% and an MgO content of 0 to 10 wt% A backfill material characterized by containing a chemical component. delete The method according to claim 1,
Wherein the sodium hydroxide solution has a concentration of 1 to 10 N. The method according to claim 1,
Wherein the backfill further comprises 0.5 to 10 wt% of an additive,
Wherein the additive is at least one selected from the group consisting of a defoaming agent, a retarder, a thickener, a pigment, a crack reducing agent, an antimicrobial agent and an expanding agent. The method according to claim 1,
Backfill material characterized in that the compressive strength of the backfill material is 1 to 30 days curing, the compressive strength when held up to 3.5 to 28 ㎏ _f / ㎠. (I) treating the natural oyster shell with a sulfuric acid solution to prepare a sulfuric acid treated oyster shell;
II) any one selected from the group consisting of loess, coal fly ash, and mixtures thereof in the sulfated oyster shell of step I); And sodium hydroxide solution to produce a solid fire; And
III) mixing the natural oyster shell and the fly ash in the fire of step II) to produce a backfill material;
And (iv) placing and curing the backfill material in step (III)
The sulfated oyster shell has a CaO content of 40 to 70 wt%, an SO ₃ content of 10 to 50 wt%, an Na ₂ O content of 0 to 10 wt%, a SiO ₂ content of 2 to 3 wt% and an MgO content of 0 to 10 wt% Characterized in that it contains a chemical component. The method according to claim 6,
The backfill material is 1 to 30 days curing when from 3.5 to 28 ㎏ _f / ㎠ backfill material construction method, characterized in that the compressive strength is maintained up.

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