KR20150048682A - Dredging sludge solidified agent - Google Patents

Abstract

The present invention relates to a banking material composition using red mud sludge and a manufacturing method thereof and, more specifically, to a banking material composition using red mud sludge, which significantly reduces moisture content of red mud sludge by using incineration residues having much CaO for absorbing and generating heat and a solidification agent having petroleum coke desulfurization gypsum, thereby being used for burying a low-lying rural area and in banking materials, and a manufacturing method thereof. The banking material comprises 10-80 parts by weight of the solidification agent with respect to 100 parts by weight of red mud sludge whose moisture content is 30-60% and particle size is 0.001-0.5 cm, wherein the solidificaiton agent comprises 10-150 parts by weight of petroleum coke desulfurization gypsum with respect to 100 parts by weight of incineration residues whose content of CaO is not less than 20%.

Description

DREDGING SLUDGE SOLIDIFIED AGENT [0001]

The present invention relates to an embankment composition using red mud sludge, and more particularly, to a composition for embankment using red mud sludge, and more particularly, to a composition for red-mud sludge containing a CaO-rich incinerator residue and petro- The present invention relates to an embankment composition using red mud sludge which can be used as embankment material for landfill and lowland farmland by abruptly reducing abrasion resistance.

Red mud is a by-product of aluminum hydroxide / alumina (Al (OH) ₃ / Al ₂ O ₃ ) from bauxite. The major component of red mud is Fe ₂ O _{3, which} is reddish hue and red mud, and about 200,000 tons per year is produced as a by-product in Korea. These red muds are discharged into the sludge state with a water content of about 45% at the time of final discharge. Industrial by-products in such a water state are difficult to recycle.

Therefore, at present, quicklime, cement and iron sulfate are mainly used to utilize red mud sludge.

The above-mentioned cement can not be said to be environmentally friendly because it is produced by calcining limestone, clay, or iron ore and pyrolysis at high temperature using coal as a fuel in manufacturing cement, that is, it is a serious product of natural resources and natural damage.

Therefore, there is a demand for a new concept of high-fire firefighting without using quicklime, cement and iron sulfate, and a technology for recycling sludge using the same.

DISCLOSURE Technical Problem Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a red mud sludge containing a large amount of CaO-containing incineration residue and petro- And to provide an embankment composition using red mud sludge which can be used as embankment material by embedding low-lying agricultural land by abruptly reducing water content.

In order to solve the above-mentioned technical problem, the embankment composition according to the present invention comprises 10 to 80 parts by weight of a fire-proofing agent, based on 100 parts by weight of red mud sludge having a water content of 30% to 70% and a particle diameter of 0.001 to 0.5 cm, The fireproofing comprises 10 to 150 parts by weight of petroleum gypsum desulfurization gypsum based on 100 parts by weight of incineration residues having a calcium oxide (CaO) content of 20% or more.

It is preferable that the incineration residue has a particle diameter of 0.001 to 0.1 cm. The specific surface area of the incineration residue is more preferably 2,000 to 6,000 cm < 2 > / g.

The incineration residue may be any one selected from the group consisting of coal ash, paper sludge incineration residue, biomass incineration residue, sewage sludge incineration residue, RDF (Refuse Derived Fuel) incineration residue and RPF (Refuse Plastic Fuel) incineration residue .

The cement may further include 5 to 20 parts by weight based on 100 parts by weight of the incineration residue. The cement may further include cement to prevent the red mud sludge from solidifying and solidifying the solidified sludge.

The red mud sludge may further include a fixing agent for preventing the red mud sludge from sticking to the manufacturing facility during the process of manufacturing or transferring the solidified product resulting from solidification of the red mud sludge, It is preferable to further incorporate a part by weight.

Also, it is preferable that the anti-bonding agent is any one or a mixture of two or more selected from the group consisting of coal ash, calcium limestone, fine feldspar, fine silica powder and granite fine powder having a calcium oxide (CaO) content of less than 5%.

The method for manufacturing a embankment composition using red mud sludge according to the present invention comprises the steps of: 1) preparing a fireproof material according to any one of claims 1 to 5; 2) mixing 10 to 80 parts by weight of the fire-fighting solution with 100 parts by weight of red mud sludge; And 3) curing a mixture of the red mud sludge and the solidified sludge.

Also, the step 3) is preferably performed by curing the mixture at room temperature or by heating and curing the mixture.

Also, the step 3) is preferably performed until the water content of the mixture becomes 30% or less.

According to the present invention, it is possible to obtain an embankment with the use of industrial by-products such as red mud sludge, incineration residue and petro cough.

In particular, the water content of red mud sludge is drastically reduced by including incineration residues containing a large amount of CaO, which absorbs and exotherms, and petro coke desulfurization gypsum, which can be utilized as landfill and embankment for lowland farmland.

Hereinafter, the embedding composition and the method for producing the embankment using red mud sludge according to the present invention will be described in detail.

First, the components and the function of the embankment using red mud sludge according to the present invention will be described.

The embedding composition using red mud sludge according to the present invention has a moisture content of 30% to 60%, and has a specific surface area of 2,500 / g to 4,500 / g with respect to 100 parts by weight of red mud sludge having a particle size of 0.01 to 0.5CM. To 80 parts by weight.

The red mud sludge harsh fire includes 10 to 150 parts by weight of petro coke desulfurization gypsum based on 100 parts by weight of incineration residues having a calcium oxide (CaO) content of 20% or more.

In addition, the incineration residues with a calcium oxide (CaO) content of 20% or more can be recovered from coal ash, paper sludge incineration residue, biomass incineration residue, sewage sludge incineration residue, RDF (Refuse Derived Fuel) incinerator residue and RPF (Refuse Plastic Fuel) Or a mixture of two or more thereof.

Calcium oxide, which is abundantly contained in the incineration residue, reacts with water and absorbs, exotherms and expands into calcium hydroxide. The reaction formula is as follows.

CaO + H ₂ O- > Ca (OH) ₂ + 15.6 mol ^-1

Although the incineration residue is usually recycled as a concrete admixture, incineration residues containing a large amount of calcium oxide can not be used as a concrete admixture because of its absorption, exothermic and expansion characteristics.

Therefore, the present invention utilizes incineration residues which can not be utilized as a concrete admixture material.

That is, when the red mud sludge having a high water content and the incineration residue containing a large amount of calcium oxide are mixed, the moisture is reduced in the red mud sludge while the calcium hydroxide is generated in the above reaction. Also, since the heat generated by the above reaction evaporates the moisture of the red mud sludge, the water content of the red mud sludge can be further reduced.

On the other hand, incineration residues containing 20% or more of calcium oxide are coal ash, paper sludge incineration residue, biomass incineration residue, sewage sludge incineration residue, RDF incinerator residue and RPF incinerator residue.

The specific surface area of the incineration residue preferably ranges from 2,500 to 6,000 cm < 2 > / g. If the specific surface area of the incineration residue is less than 2,500 cm 2 / g, the effect of reducing the moisture content upon solidification of the red mud sludge deteriorates due to insufficient particulate matter. When the specific surface area exceeds 6,000 cm 2 / g, And scattered during transportation, and the facility operation is degraded.

Coal materials are produced in a large number of power plants. Particularly, coal ash produced in a power plant having an in-furnace desulfurization system has a high content of calcium oxide. In the case of the in-furnace desulfurization system, since coal and limestone are mixed and burned, a large amount of Free CaO is contained in coal ash.

Meanwhile, Petrokoux desulfurization gypsum contains a large amount of gypsum and CaO in the incineration as it mixes petro coke and limestone for incineration in the incinerator that burns petro coke.

It is preferable that the Petro coke desulfurization gypsum has a specific surface area of 2,500 to 4,000 cm < 2 > / g. When the specific surface area is less than 2,500 cm 2 / g, the activity is lowered due to insufficient particulate matter, and the effect of decreasing the water content is lowered. When the specific surface area exceeds 4,000 cm 2 / g, the activity is increased but the apparent density is lowered during the transfer of the fire. And the facility operation is degraded.

In addition, it is preferable that cement is further included to prevent re-slurrying of the formed filler solidified by solidification of red mud sludge.

The cement may be any one or a mixture of two or more selected from the group consisting of blast furnace slag cement, portland cement and fly ash cement.

The cement reacts with the moisture contained in the red mud sludge. The intensity of the cement at the initial age according to the hydration reaction is formed by the C-S-H gel produced simultaneously with a large amount of ettringite skeleton. In addition, the CSH gel surrounds Etringite. As the age elapses, the amount of the CSH gel continuously increases and the CSH gel tightly fills the pores of the cured paste, forming a dense network network structure with etringing, .

The cement is preferably incorporated in an amount of 5 to 20 parts by weight based on 100 parts by weight of the incineration residue. When cement is incorporated in an amount of less than 5 parts by weight, a predetermined strength can not be exhibited. Therefore, there is a risk that a slip composition becomes a slurry again when it comes into contact with rain, ground water and surface water. If it exceeds 20 parts by weight, The strength is greatly increased, but it is too hard to be used as an artificial tile or soil material, which is a soil substitute agent, that is, it may not satisfy the characteristics of soil dynamical embankment.

In order to prevent the solidification of the solidified or solidified red mud sludge from being adhered to the manufacturing facility during the manufacture or transportation of the solidified product, it is preferable that the solidification preventing agent is further included.

It is preferable that the anti-bonding agent is any one or a mixture of two or more selected from the group consisting of coal ash, calcium limestone, fine feldspar, fine silica powder, and granite fine powder having a calcium oxide (CaO) content of less than 5%.

The anti-adhesion agent is preferably incorporated in an amount of 10 to 100 parts by weight based on 100 parts by weight of the incineration residue. If less than 10 parts by weight of the red mud sludge is mixed with the plant, the red mud sludge may be adhered to the equipment during the process, The effect can be reduced by half.

Hereinafter, a description will be given of a method for producing an embankment using red mud sludge according to the present invention.

The method for manufacturing the embankment using red mud sludge according to the present invention comprises the steps of: 1) manufacturing the above-mentioned solidified fire; 2) mixing 10 to 80 parts by weight of the fire-fighting solution with 100 parts by weight of red mud sludge; And 3) curing a mixture of the red mud sludge and the solid fire.

If the blending ratio is less than 10 parts by weight in the second step, the water content can not be sufficiently reduced and the blend can not be used as an embankment. If the blending ratio exceeds 80 parts by weight, the water content becomes too low, It becomes difficult to work with embankment and cover.

Also, the step 3) is preferably performed by curing the mixture at room temperature or by heating and curing the mixture.

Also, the step 3) is preferably performed until the water content of the mixture becomes 30% or less.

Hereinafter, the present invention will be described in more detail with reference to the following examples and comparative examples. It is to be understood, however, that the following examples and comparative examples are intended to illustrate the present invention and that the scope of the present invention is not limited to the scope of these examples and comparative examples.

Example  One

First, 40 parts by weight of petroleum gypsum desulfurization gypsum, 10 parts by weight of blast furnace slag cement as an initial strength, and 30 parts by weight of a limestone fine powder as an anticorrosive agent were uniformly mixed with 100 parts by weight of high calcium coal ash with a calcium oxide content of 38% To produce a fire.

Next, 100 parts by weight of red mud sludge having a water content of 45% was mixed with 10 parts by weight of the fire-retardant prepared as described above and cured at room temperature to prepare an embankment.

Example  2

100 parts by weight of red mud sludge having a water content of 45% was mixed with 30 parts by weight of the same fire retardant as that of Example 1 and cured at room temperature to prepare an embankment.

Comparative Example

In the comparative example, natural soil mixed with clayey soil and sandy soil was sampled, and samples were prepared without adding a firefly.

Performance Test Methods and Results of Embankment

As shown in Table 1 below, the water content was measured by the KS F 2306 method and the compressive strength and permeability test was conducted by the method of KS F 2343 and KS F 2322.

Experiment Way Remarks Moisture content KS F 2306 How to measure water content of soil Compressive strength KS F 2343 Uniaxial compressive strength method Permeability coefficient KS F 2322 Variable Strain Test

The test results for Examples 1, 2, and Comparative Example according to Table 1 are as shown in Table 2.

division Example 1 Example 2 Comparative Example Water content (%)

Immediately after mixing 39.7 34.4 46.2 1 day 36.2 31.4 - 3 days 32.1 28.7 - Compressive strength (kgf / ㎠)
3 days 8.7 10.1 0.62 7 days a year 22.2 27.6 0.62 28 days old 38.3 39.2 0.62 Permeability Coefficient (cm / sec) 3 days 3.27 × 10 ^-4 3.38 × 10 ^-4 3.21 x 10 ^-4

(1) Change in water content

Table 2 shows the water content of the dredged mixed soil prepared in Examples 1 to 3 over time. As can be seen in Table 2, the water content of Redmud sludge was 45.0% before the fire-fighting, but it was found that the water content decreased sharply over time. As described above, the reason why the water content is greatly reduced is that an exothermic reaction occurs immediately when the fire is mixed with the red mud sludge and the hydration reaction proceeds at the same time. Also, as the time passes, the water content rapidly decreases due to hydrate formation and natural drying. It can be seen that all the cases of Examples 1, 2 and 3 were improved to be recycled immediately with embankment or the like. If it is used as embankment after 3 days of natural curing, it is expected to contribute not only to easier handling but also to increase the compressive strength.

(2) Change in uniaxial compressive strength

As shown in Table 2, the unconfined compressive strength of the embankment composition produced by the present invention is larger than that of natural soil. This value is much higher than 0.5kgf / cm ² and 1.0kgf / cm ² , which are the strength standards of cover materials and embankment materials, and shows strengths that can be used for various soil materials such as soft ground improvement material, car water material, back fill material .

This is due to the reduction of water content and the surface modification of red mud sludge by the exothermic reaction when mixed with fire and fire, and the consolidation of particles is achieved by consolidation of the particles, and calcium silicate reaction is induced by CaO and SiO ₂ components, Because of the solidification reaction that can ensure the strength of the reaction. In addition, the water content of Red Mud sludge is relatively low due to the absorption of the fire, and the clay and colloidal components, which are fine particles, are isolated by the water absorption, ion exchange, pozzolan and carbonation reaction of the fire, And the uniaxial compressive strength is increased.

(3) Permeability characteristics

As can be seen from the measurements of the permeability coefficient of Table 2, the permeability coefficient of the embankment was not significantly different from that of the ground surface. In the case of Middlesex country, New Jersey, USA, the permeability coefficient of the landfill cover material is 1 × 10 ^-3 cm / sec to 1 x 10 < ^-7 > cm / sec. It is considered that the embankment composition using red mud sludge produced by the present invention will have sufficient permeability as a daily and intermediate landfill material.

Claims (4)

Wherein the red mud sludge has a water content of 30% to 70%, 10 to 200 parts by weight of a fireproofing material,
The fireproofing comprises 10 to 150 parts by weight of petroleum gypsum desulfurization gypsum based on 100 parts by weight of incineration residues having a calcium oxide (CaO) content of 20%
The incineration residue may be any one or a mixture of two or more selected from the group consisting of coal ash, paper sludge incineration residue, biomass incineration residue, sewage sludge incineration residue, RDF (Refuse Derived Fuel) incineration residue and RPF (Refuse Plastic Fuel) ≪ / RTI >
The method according to claim 1,
In order to prevent re-slurrying of the solidified solid resulting from solidification of the red mud sludge, at least one of cement or blast furnace slag fine powder is further included,
Wherein the cement or blast furnace slag fine powder further comprises 5 to 100 parts by weight based on 100 parts by weight of the incineration residue.
The method according to claim 1,
Further comprising a fixing agent for preventing the red mud sludge from being adhered to the manufacturing facility during the process of manufacturing or transporting the solidified product resulting from solidification of the red mud sludge,
10 to 100 parts by weight of the anti-seizing agent is further mixed with 100 parts by weight of the incineration residue,
Wherein the anticaking agent is any one or a mixture of two or more selected from the group consisting of coal ash, calcium limestone powder, feldspar fine powder, fine silica powder and fine granite powder having a calcium oxide (CaO) content of less than 20%.
The method according to claim 1,
A pH-reducing agent is further included to reduce the pH of the fillet,
The pH reducing agent is an acidic powder having a pH of 4 or less by mixing directly in a form of concentrated sulfuric acid or dilute sulfuric acid,
Wherein the pH-lowering agent is further incorporated in an amount of 5 to 100 parts by weight based on 100 parts by weight of the incineration residue.