KR20120047133A - Solidifier of sludge with high water containing rate and method of the same using - Google Patents

Abstract

PURPOSE: A solidifying material for sludge of high moisture content and a method for solidifying the sludge of high moisture content are provided to effectively suppress the generation of ammonia by adjusting pH values. CONSTITUTION: A solidifying material for sludge of high moisture content includes 20-400 parts by weight of sodium aluminum sulfate or sodium aluminum fluoride based on 100 parts by weight of alkaline aid. The sodium aluminum sulfate or the sodium aluminum fluoride is the byproduct of a polysilicon manufacturing process. The alkaline aid is based on either of quicklime or light burned dolomite. The solidifying material further includes 250-1000 parts by weight of incineration remains containing 20-70% of calcium oxide based on 100 parts by weight of the alkaline aid.

Description

High function sludge solidified fire and high functional sludge solidification method using same {SOLIDIFIER OF SLUDGE WITH HIGH WATER CONTAINING RATE AND METHOD OF THE SAME USING}

The present invention relates to a high sewage sludge solidified material and a solidification method using the same, by reducing the moisture content of the high functional sludge by using the absorption and exothermic action of CaO contained in a large amount of neutralization heat and incineration residue generated by the reaction of the alkali and oxidant. And it relates to a high-functional sludge solidified material and deodorization and microorganism sterilization and solidification method using the same.

Sewage sludge, wastewater sludge, purified water sludge, dredged sludge and mud sludge with high moisture content are representative environmental pollutants, which have been treated by ocean dumping, landfilling, etc., and now restore the environment contaminated by the pollutants. There are many ways to make it happen.

For example, sewage sludge, which discharges more than 6,000 tons per day, has been banned from landfills since July 2003, and even the most easily disposed of dumping at sea is the London Dumping Treaty, which is banned from 2012.

In Korea, where the country is narrow, efficient and safe treatment should be sought in order to prevent environmental pollution around the country and to prevent the environment from being contaminated by leachate from sludge.

Currently, local governments, including metropolitan landfills, are preparing solidification facilities that manufacture artificial soils that can be used as various ground materials such as cover soil, landfill, sewage and backfill by reducing the water content of high-functional sludge. Therefore, it is necessary to develop an excellent solidified material in terms of productivity and economic efficiency by efficiently solidifying a watery sludge.

In the research of the conventional sewage sludge solidified materials, strong alkali materials such as quicklime and cement were mainly used, and problems such as odor and reslurization were caused, and in order to compensate for these, acidic materials such as expensive sulfuric acid and iron sulfate In order to reduce the ammonia emission by additionally added, the price of raw materials to be added is high, and it is not economically competitive. In addition, in order to solve the problem by supplementing the drying and curing of the treatment apparatus to compensate for the material defects of the material, the treatment process itself has a structure that causes a high cost, the operation of the heating curing plant is not smooth operation to be.

Moreover, cement and quicklime emit about 0.55 tons of carbon dioxide in the calcination process for the CO ₂ decomposition of limestone (CaCO ₃ , CaOCO ₂ ) and about 0.40 tonnes of carbon dioxide when burning fossil fuels in the firing process. of the atmosphere with a material which is carbon dioxide of about 1 ton discharged each time to produce CO ₂ There is a high correlation between concentration and cement and quicklime production.

The present invention has been made to solve the above-mentioned problems, the object of the present invention is the water content of high-functional sludge by using the absorption and exothermic action of CaO contained in a large amount of neutralization heat and incineration residue generated by the reaction of alkali and oxidant It is to provide a high-functional sludge solidified material and solidification method to reduce the deodorization and sterilization of microorganisms.

The high-functional sludge solidified material according to the present invention includes an oxidizing agent which is an alkali agent made of at least one of quicklime or light bovine dolomite and an oxidizing agent of SAS (Sodium Aluminum Sulfate) or SAF (Sodium Aluminum Fluoride), which is a strong acid generated as a by-product from polysilicon manufacturing process; It consists of incineration residues with calcium oxide (CaO) content of 20% to 70%.

In addition, the incineration residue is selected from the group consisting of coal ash, paper sludge incineration residue, biomass incineration residue, petroleum coke incineration residue, sewage sludge incineration residue, RDF (Refuse Derived Fuel) incineration residue and RPF (Refuse Plastic Fuel) incineration residue. It is preferred that it is one or a mixture of two or more.

The incineration residues preferably have a specific surface area of 2,500 to 6,000 / g.

In addition, the SAS (Sodium Aluminum Sulfate) or SAF (Sodium Aluminum Fluoride) is generated as a by-product of the polysilicon manufacturing process, the pH is preferably 2-3. It is preferably included 10 to 500 parts by weight based on 100 parts by weight of the incineration residue.

The high-function sludge solidification method according to the present invention comprises the steps of: 1) preparing a solidified material of any one of claims 1 to 6; 2) to 100 parts by weight of the high-functional sludge, 5 to 100 parts by weight of the solidified material Doing; And 3) curing the mixture of the high functional sludge and the solidified material.

In addition, step 3) is preferably carried out by room temperature curing or heating curing the mixture.

In addition, step 3) is preferably performed until the water content of the mixture is 60% or less.

In addition, the sludge is preferably any one of sewage sludge, wastewater sludge, purified water sludge, mud sludge and dredging sludge or a mixture of two or more.

According to the present invention, there is an effect that the water content of the high functional sludge is sharply lowered by using the heat of neutralization generated by the reaction of the alkali agent and the oxidant.

In addition, the effect of reducing moisture content is increased by the exothermic and absorption action of CaO contained in light dolomite and quicklime, or incineration residues.

In addition, by adjusting the pH to weak alkali effectively suppress the generation of ammonia is possible to reduce the odor.

Hereinafter, a high functional sludge solidified material and a solidification method using the same according to the present invention will be described in detail.

First, the components and actions of the high functional sludge solidified material according to the present invention will be described.

The high-function sludge solidified material according to the present invention includes an alkali agent composed of at least one of quicklime or hard bovine dolomite and an oxidizing agent which is a strong acid substance (SAS) or sodium aluminum fluoride (SAF), which is a strong acid generated as a by-product in the polysilicon manufacturing process. do.

When the alkali and oxidants react with water contained in the high-functional sludge, a neutralization reaction occurs.

Oxidizers of sodium acid sulfate (SAS) or sodium aluminum fluoride (SAF) and alkaline agents such as quicklime and light dolomite, which are generated as by-products in the production process of polysilicon, which is a strong acid, cause rapid reaction and heat of neutralization. The neutralization heat causes the water contained in the high-functional sludge to evaporate, thereby lowering the water content.

In addition, the SAS (Sodium Aluminum Sulfate) or SAF (Sodium Aluminum Fluoride) not only plays a role in causing a neutralization reaction with an alkaline agent but also exhibits a cohesive effect to prevent adhesion to a facility when mixed with a high function sludge to improve facility mobility. It also plays a role.

The polysilicon is a material composed of small silicon crystals that convert light energy into electrical energy in solar cells. As the production of the modern photovoltaic industry increases, the production of polysilicon is being operated in Korea. . Such polysilicon is prepared by melting and reducing carbon of silicon, that is, by adding silicon silicon (MG-Si) produced by heating a mixture of quartz extracted from silicon with a carbon compound and heating it with a monosilane or trichlorosilane. The chemical reaction gives a purified polysilicon. In particular, polysilicon is prepared using sulfuric acid, silica sand, and fluorspar as a main material, and it is preferable to have a strong acidity of 3 or less as SAS (Sodium Aluminum Sulfate) or SAF (Sodium Aluminum Fluoride) discharged as a by-product. If the pH is 3 or more, the neutralization reaction with the alkaline substance is lowered, so that a predetermined initial fever cannot be obtained.

In addition, the mixing ratio of the sodium aluminum sulfate (SAS) or the sodium aluminum fluoride (SAF) and the alkaline agent is preferably 20 to 400 parts by weight based on 100 parts by weight of the alkaline agent. If the oxidizing agent is less than 20 parts by weight, the neutralization reaction does not occur sufficiently, so that the amount of neutralization heat is not generated and the effect of lowering the pH does not appear. In addition, when the oxidizing agent is more than 400 parts by weight, the amount of neutralization heat is generated so that the water evaporation effect also does not meet the expectation, the pH is sharply lowered to reduce the ammonia effect, but on the contrary, there is a problem with strong acidity.

The solidifying material according to the present invention further includes an incineration residue having a calcium oxide (CaO) content of 20% to 70%.

Calcium oxide contained in a large amount in the incineration residue reacts with water to be absorbed, exothermic, and expand to form calcium hydroxide. Therefore, the water content of the high functional sludge can be reduced. The reaction scheme is as follows.

CaO + H ₂ O-> Ca (OH) ₂ +15.6 mol ^-1

Although such calcium oxide is contained in the quicklime, light dolomite and the like, it is preferable to utilize incineration residue having a calcium oxide content of 20% or more in terms of cost reduction and environmental aspects.

Although incineration residues are generally recycled to concrete admixtures, incineration residues containing a large amount of calcium oxide are incapable of being used as concrete admixtures because of their absorption, heat generation, and expansion characteristics.

Therefore, the present invention is to use incineration residues that can not be utilized as a concrete admixture.

That is, when the incineration residue containing a large amount of calcium oxide is mixed with the sludge having a high water content, the water of the sludge is reduced while calcium hydroxide is produced by the above reaction. In addition, since the heat generated by the above reaction evaporates the water of the sludge, it is possible to further reduce the water content of the sludge.

Incineration residues containing more than 20% of calcium oxide are coal ash, paper sludge incineration residue, biomass incineration residue, petroleum coke incineration residue, sewage sludge incineration residue, RDF incineration residue and RPF incineration residue.

Coal ash is produced in many power plants. In particular, coal ash produced in a power plant having a desulfurization method in a furnace has a high content of calcium oxide. In the furnace desulfurization method, coal and limestone are mixed and burned, so the coal ash contains a large amount of free CaO.

In contrast, coal ash produced in power plants with separate desulfurization facilities has less than 5% calcium oxide.

Table 1 shows the differences between coal ash in power plants with separate wet desulfurization equipment and coal ash in power plants by furnace desulfurization.

Item Power plant coal ash with separate desulfurization Furnace  Desulfurization Power Plant Coal Ash Combustion fuel Coal (Import Bituminous Coal) Coal, limestone, waste tire (some power plants) Combustion temperature About 1350 ℃
-High combustion efficiency for economic power plant operation, reduction of coal ash generation rate and high quality coal ash discharge About 850 ℃
-Nitrogen emission reduction while decarbonation temperature range Exhaust Gas Desulfurization Facility Separate wet desulfurization facility Desulfurization Reaction with Limestone Mixture Exhaust gas denitrification plant Separate denitrification equipment Maintain low combustion temperatures and spray ammonia and other chemicals into boilers Chemical composition SiO _{2 ,} Al ₂ O _{3 ,} Fe ₂ O ₃ Due to limestone mixing
High free CaO component. Vitrification Degree high low Main recycling purpose Peak season with concrete admixture
Recycle all generation Clay substitute cement raw material,
Landfill of waste disposal site through long distance transportation Advantages and problems of using concrete admixture -Increased long-term strength with pozzolanic activity
- Improved workability
-Reduced unit quantity (durability, improved strength)
-Reduced heat of hydration (structure crack prevention) -Free CaO exothermic reaction
-Unit quantity increase (strength, durability decline)
-Increased heat of hydration (structure cracking)
-Reduced workability Etc KS L 5405 conformity product generation Do not satisfy the chemical composition and physical performance of KS L 5405

That is, the coal ash produced by the furnace desulfurization method contains a large amount of calcium oxide, but the coal ash produced in a facility equipped with a separate desulfurization device contains a very small amount of calcium oxide. Therefore, as described above, the coal ash produced in the facility equipped with a separate desulfurization device contains a small amount of calcium oxide, so that it does not have heat generation and absorption properties, and thus it can be recycled as a concrete admixture.

In other words, the incineration residue used in the solidified fire of the present invention is a coal ash produced by the desulfurization method with a high CaO content.

At this time, it is preferable that 250-1,000 weight part of said incineration residues mix with respect to 100 weight part of said alkali chemicals.

If the amount of the incineration residue is less than 250 parts by weight, the amount of alkali and oxidant is relatively increased, resulting in insufficient economic efficiency. In particular, the amount of the solidified material and the high-functional sludge mixture is insufficient due to the insufficient powder content of the incineration residue in the form of fine powder. It is increased and attached to the equipment, which affects the equipment mobility.

In addition, when the mixing amount of the incineration residue is more than 1,000 parts by weight, the mixing amount of the alkali agent and the oxidizing agent is relatively reduced, so that the neutralization heat is generated less and the water evaporation effect is reduced, thereby affecting the facility operability.

On the other hand, the incineration residue will contain unburned carbon, depending on the combustion environment, it usually contains 1 to 20%. The unburned carbon has a property of adsorbing ammonia gas and heavy metal generated when the solidified material is incorporated into the sludge because it is porous.

Hereinafter, a high function sludge solidification method according to the present invention will be described.

First, the solidified material is prepared, and then 5 to 100 parts by weight of the solidified material is uniformly mixed with respect to 100 parts by weight of the sludge. If the solidified material is mixed at less than 5 parts by weight, the moisture content is not sufficiently reduced. If it is mixed at more than 100 parts by weight, the moisture content is too low, and the mixture is scattered, and transportation and laying operations are difficult.

Finally, room temperature curing or heating curing is performed until the water content of the mixture of the sludge and the solidified material is 60% or less.

Example  One

100 parts by weight of light calcined dolomite, a solid material consisting of 200 parts by weight of sodium aluminum sulfate (SAS) having a pH of 2.3 and 600 parts by weight of RPF incineration residue having a calcium oxide content of 42% was prepared.

Next, with respect to 100 parts by weight of the dyeing wastewater sludge having a water content of 83.2%, 50 parts by weight of the solidified material was mixed to prepare an artificial soil.

Example  2

100 parts by weight of quicklime, a solid ash composed of 150 parts by weight of sodium aluminum sulfate (SAS) having a pH of 2.3 and 400 parts by weight of biomass incineration residue having a calcium oxide content of 22%.

Next, the artificial soil was prepared by mixing 30 parts by weight of the solidified material with respect to 100 parts by weight of sewage sludge having a water content of 82.3%.

Comparative example  One

With respect to 100 parts by weight of quicklime, a solidified material consisting of 400 parts by weight of biomass incineration residue having a calcium oxide content of 22% was prepared.

Next, 20 parts by weight of the solidified material was mixed with 100 parts by weight of sewage sludge having a water content of 82.3% to prepare artificial soil.

Performance Test Method and Result of Artificial Soil

As shown in Table 2 below, the water content was measured by the KS F 2306 method and the compressive strength test was performed by the KS F 2343 method.

Experiment Way Remarks Water content KS F 2306 How to measure the water content of soil Compressive strength KS F 2343 Uniaxial compressive strength method

1) water content change

The moisture content of artificial soils prepared by Examples 1, 2 and Comparative Example 1 according to time is shown in Table 3 below. As confirmed in Table 3, as the solidified material according to the present invention is mixed, the water content of the dyeing wastewater sludge was 83.2%, but it can be seen that the water content decreases rapidly with time. The moisture content is greatly reduced because, as described above, the exothermic reaction occurs immediately after the solidified material is mixed with the sludge and the hydration reaction proceeds simultaneously. In addition, the water content gradually decreases due to hydrate formation and natural drying over time.

In Example 2, after one day of natural curing, strong cohesiveness disappeared and transferred to a physical state such as natural soil with a little moisture, but Comparative Example 1 still remained strong cohesive in sludge form and remained in a high water content mud state. have.

division Immediately after improvement 3 hours 1 day 3 days 5 days 7 days Example 1 51.9% 43.2% 41.4% 39.7% 38.0% 36.0% Example 2 61.0% 52.1% 45.1% 43.2% 41.8% 40.9% Comparative Example 1 61.2% 53.9% 48.3% 46.4% 45.2% 44.4%

(2) Uniaxial compressive strength  change

Table 4 shows the change in uniaxial compressive strength of the artificial soil prepared by Example 1, Example 2 and Comparative Example 1, respectively. As can be seen through the seven days of curing, Example 1 showed 1.77kgf / cm ² , Example 2 showed 1.39kgf / cm ² , and Comparative Example 1 showed 0.47kgf / cm ² . Example 1 and Example 2 is 0.5kgf / cm ² which is the strength standard of cover and fill material And values exceeding 1.0 kgf / cm ² and exhibited strength expressions that can be utilized as a lining material and various ground materials. This is because water absorption and the surface modification of the sludge occurs due to the absorption and heating reaction when mixed with the solidified material to achieve the consolidation promoting effect by the consolidation of the particles to enhance the strength. In addition, the water content of the sludge is relatively lower due to the absorbency of the solidified material, and the clay and colloidal components, which are fine particles are separated by the absorbent and ion exchange, pozzolanication, and carbonation reaction of the solidified material. Uniaxial compressive strength is increased.

On the other hand, the solidified material in which the oxidant is not mixed in Comparative Example 1 does not generate heat of neutralization, so that the amount of initial evaporation is small and there is no coagulation effect, so it is attached to the facility, resulting in reduced productivity and still maintaining a mud-like state. It is judged that it is not expressed.

division Compressive strength ( kgf Of cm ² ) 3 days 7 days 28 days Example 1 1.09 1.77 2.51 Example 2 1.02 1.39 2.22 Comparative Example 1 0.34 0.47 0.89

(3) before and after immersion Uniaxial compressive strength  change

When the artificial soil manufactured by the present invention is used as a daily cover material for landfills, it must have the required strength and at the same time, the reslurrification phenomenon and the strength reduction phenomenon caused by the inundation such as heavy rain and heavy snow, which are the climatic characteristics of Korea, should not occur. something to do. Therefore, in this experiment, the uniaxial compressive strength changes before and after 1 day immersion were investigated for artificial soils cured for 7 days.

The change in uniaxial compressive strength before and after immersion is shown in Table 5 below. As can be seen through this, the artificial soil prepared by Example 1 is -0.08kg / cm ² , and the artificial soil prepared by Example 2 is -0.11kg / cm ^2. The rate of change of strength was shown. On the other hand, Comparative Example 1 showed a large decrease in strength compared to the Example according to the present invention of -0.26kg / cm ² .

As can be seen from the above results, the change in uniaxial compressive strength before and after immersion of the artificial soil produced by the present invention showed a relatively small decrease rate, which is obvious even when the sludge is changed to a dense crystal structure while producing a hydrate by solidification treatment. It seems that absorption does not occur. Therefore, when the mixture prepared according to the present invention is used in landfills, reslurrying or strength deterioration in flooding due to snowfall is insignificant, and even when used as a cover material of landfills, it is expected that it will not significantly affect the operation of vehicles and equipment during rainy weather. .

Before immersion (kg /) After immersion (kg /) Intensity change Example 1 1.77 1.69 -0.08 Example 2 1.39 1.28 -0.11 Comparative Example 1 0.47 0.21 -0.26

(4) heavy metal elution

Table 6 below shows the heavy metal elution test results of the artificial soil prepared by Example 1. As can be seen from this, most of heavy metals were not eluted and a small amount of copper was detected when applied to the waste dissolution test method in Korea, but the environmental standard was satisfied. This is because the heavy metal is substituted or fixed into the crystal structure by being fixed by the hydrate generated in the hydration reaction. Therefore, the dissolution concentration in all these experiments is much lower than the standard value or is not detected, so the secondary contamination due to heavy metal leaching is not considered to be a concern even if the sludge is solidified and used as daily cover material for landfills.

 Hazardous Substances
 Dissolution method CD As Pb Hg Cr ^{6 +} Cu Org .P TCE PCE Waste Dissolution Test Method
(KSLP) standard 0.3 1.5 3.0 0.05 1.5 3.0 1.0 0.1 0.3 mixture N.D. N.D. N.D. N.D. N.D. 0.003 N.D. N.D. N.D. US EPA
(TCLP) standard 1.0 - 5.0 0.2 5.0 - - - - mixture N.D. - 0.004 N.D. N.D. - - - - * N.D: Not Detected

Claims (8)

Using neutralization heat, characterized in that it comprises 20 to 400 parts by weight of an oxidizing agent of sodium aluminum sulfate (SA) or sodium aluminum fluoride (SAF), which is a byproduct of polysilicon manufacturing process, based on 100 parts by weight of an alkali agent composed of at least one of quicklime or light dolomite. Low alkali high function sludge solid fire.
The method of claim 1,
A low alkali high-functional sludge solidified material using neutralization heat, characterized in that it further comprises 250 to 1,000 parts by weight of an incineration residue having a calcium oxide (CaO) content of 20% to 70% based on 100 parts by weight of the alkali chemicals.
The method of claim 2,
The incineration residue is any one selected from the group consisting of coal ash, paper sludge incineration residue, biomass incineration residue, petrol coke incineration residue, sewage sludge incineration residue, RDF (Refuse Derived Fuel) incineration residue and RPF (Refuse Plastic Fuel) incineration residue Or a low alkali high functional sludge solidified material, characterized in that it is a mixture of two or more.
The method of claim 3, wherein
The incineration residue is a low alkali high functional sludge solidified material, characterized in that the specific surface area of 2,500 ~ 6,000 / g.
The method of claim 1,
Said SAS (Sodium Aluminum Sulfate) or SAF (Sodium Aluminum Fluoride) is a low alkali high functional sludge solidified material, characterized in that the pH is 2-3.
1) preparing a solidified material according to any one of claims 1 to 5;
2) mixing 5 to 100 parts by weight of the solidified material with respect to 100 parts by weight of high content sludge; And
3) curing the mixture of the high-functional sludge and the solidified material; high-functional sludge solidification method comprising a.
The method of claim 6,
Step 3) is a high-function sludge solidification method characterized in that the mixture is carried out at room temperature curing or heating curing.
The method of claim 7, wherein
The sludge solidification method of claim 1, wherein the sludge is any one or a mixture of two or more of sewage sludge, wastewater sludge, purified sludge, mud sludge and dredging sludge.