KR20070089021A - Manufacturing method of solidification agent for organic or inorganic waste resources - Google Patents

Abstract

A method for manufacturing a solidifying agent for organic or inorganic waste is provided to prevent odor from being generated when the solidifying agent reacts with the organic or inorganic waste. For manufacturing a solidifying agent for organic or inorganic waste, firstly, sulfate composite of 50-95 wt% and strong alkali-based powder of 5-50 wt% are mixed. The mixture is cooled. Grains having radii of 2 mm or more are selected from the cooled mixture, and again crushed into grains having radii of 0.002-2 mm. The organic or inorganic waste is selected from a group consisting of sewage sludge, clean water sewage, food waste, livestock waste, waste gypsum, waste lime, and dredged soil.

Description

MANUFACTURING METHOD OF SOLIDIFICATION AGENT FOR ORGANIC OR INORGANIC WASTE RESOURCES}

The present invention relates to a method for preparing the solidifying agent for an organic / inorganic waste resource, and more particularly, to prepare a solidifying agent by appropriately mixing a sulfate compound and a strong alkali-based powder, and to prepare the solidifying agent prepared above. The present invention relates to a method for producing a solidifying agent for organic / inorganic waste resources by reacting with waste resources to evaporate moisture contained in organic and inorganic waste resources and at the same time reducing odor generated during solidification.

Organic and inorganic waste resources can be categorized into sewage sludge, purified sludge, livestock sludge (livestock sludge), food waste, waste gypsum, waste lime and dredged soil.

Firstly, sewage and water purification sludge produced in Korea generate more than 3,000 tons of sludge per day from sewage treatment plants, industrial complexes, and end plants, and each single plant or industrial complex. However, there are many problems that occur when reclaiming sludge that contains about 80% of the water, so it is reluctant to bring the landfill into the sea. Various attempts have been made. In addition, the sludge contains organic materials, so if used properly, energy can be recovered, but when it is disposed of, it can be a source of secondary pollution such as odor generation, and it is desirable to be recycled as resources in terms of waste of effective resources Do.

Waste lime is a concept that collectively refers to limestone residues generated in the process of producing quicklime, slaked lime, carbonate lime, soda ash, etc. by physically and chemically processing limestone, white rock, shell, etc. The waste lime is an environmental pollutant. Currently, the landfill is treated in the same way as landfilling, but landfilling is not preferable in terms of resource recycling. Accordingly, various attempts have been made to recycle waste lime. For example, although it was designated for use as a cover material for landfill waste landfill facilities in co-watershed landfills, there was a problem that not only there was a lot of moisture but also a lot of odor was generated, and the development of calcite fertilizer using waste lime was more competitive than investment. It was not commercialized because of low logistics costs due to low and seasonal characteristics. Meanwhile, sidewalk blocks and bricks using waste lime have been developed, but they are not produced because they fall short of KS standards and have a low recycling rate of waste lime. Attempts have been made to develop waste lime as a cement raw material and additive, but this has not been realized due to problems such as facility investment costs.

Waste gypsum is produced in large quantities in the process of desulfurization and in the process of manufacturing phosphoric acid, hydrofluoric acid, boron, and titanium. The gypsum produced in this way contains harmful impurities in itself, which can be used directly in products such as cement and gypsum board. In addition to lowering the throughput, there was a limit in throughput. In addition, there is a problem that the risk of groundwater contamination is increased if it is deposited in nature. Furthermore, to date, the waste gypsum can be recycled only through a complex purification process such as washing, neutralizing, calcining, and granulation.

Dredged soil is an inorganic waste resource generated at construction sites, and since 20 to 55% of moisture, 40 to 60% of ash, and 5 to 20% of flammable ash are incinerated, many heat sources are needed. It has been pointed out as the cause.

However, since the waste management law was amended, from July 1, 2003, incineration such as sewage sludge or dumping in the ocean was prohibited. Therefore, the reprocessing of organic and inorganic waste resources became a very important social issue.

On the other hand, in order to recycle the organic-inorganic waste resources without being landfilled, it is necessary to go through a process of solidifying them while reducing the moisture content of the organic-inorganic waste resources having high water content. To this end, conventionally, the chemical treatment before dehydration, but the secondary environmental pollution problem may occur due to the drug has been required to study the physical treatment method before dehydration. Accordingly, a method of maximizing dehydration using ultrasonic waves, which is widely used in the environmental field, has been proposed as a method of treating sludge of high function. This ultrasonic method uses the principle of applying ultrasonic waves to the sludge to break and separate the bonds between the internal and the combined water which are difficult to remove in the sludge by ultrasonic energy.

On the other hand, the solidification treatment method is an engineering method after adding a solidifying agent to dewatered sludge having a high water content. This is by adding a solidifying agent to dewatered sludge to improve the physical and chemical properties of the sludge, thereby promoting work efficiency, harmlessness and stabilization of harmful substances such as heavy metals, and at the same time improving soil mechanical properties such as strength. As the solidifying agent, various cements such as portland cement, crude steel cement, solidified cement, aluminum-based special cement, asphalt, plastic, quicklime, and the like are used.

 Among them, the method of solidifying sewage sludge cake uses a special cement as a solidifying agent, which is excellent in solidification effect, but most of them are uneconomical because they are expensive alumina cement. As another method of solidification, the technique disclosed in Korean Patent Publication No. 97-8689 is a method of utilizing wastes such as incinerators, cement kiln dust, fly ash, steelmaking slag, etc., which can serve as solidifying agents and solidifying aids. In order to promote economics by reducing the ratio, there was a problem that a severe ammonia odor occurs in the solidified solid. As a result, the solidifying agent prepared from the conventional cement and quicklime as the main raw material has a high pH when reacting with the sludge, resulting in ammonia odor from the sludge, and the odor persisted even after several years of solidification. In addition, even when using such a solid material as a cover material, there was a problem that the field workability due to the odor generated.

An object of the present invention for solving the above problems is to prepare a solidifying agent by appropriately mixing a sulfate compound and a strong alkali-based powder and to react the prepared solidifying agent with an organic and inorganic waste resources, the organic and inorganic waste resources It is to provide a method for producing an solidifying agent for organic and inorganic waste resources to evaporate moisture contained in the water and to reduce the odor generated during solidification.

Another object of the present invention is to provide a solidifying agent produced by the above production method.

In order to achieve the above technical problem, a method for preparing an organic / inorganic waste resource solidifying agent according to one feature of the present invention comprises: 1) 50 to 95% by weight of a sulfate compound and 5 to 50% by weight of a strong alkali powder; Mixing, (2) cooling the mixture, and (3) selecting the particles having a particle diameter of 2 mm or more from the cooled mixture and regrinding to a size of 0.002 to 2 mm.

The organic and inorganic waste resources are preferably any one selected from the group consisting of sewage sludge, purified water sludge, food waste, livestock waste, waste gypsum, waste lime and dredged soil.

The sulfate compound is preferably calcium sulfate (CaSO ₄ ), potassium sulfate (K ₂ SO ₄ ), sodium sulfate (Na ₂ SO ₄ ), ferrous sulfate (FeSO ₄ ), ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) and Any one or more selected from the group consisting of the hydrates are used.

The strong alkali powder is preferably any one or more selected from the group consisting of calcium oxide, magnesium oxide, calcium hydroxide, calcium carbonate, light dolomite, road mite, cement, quicklime, slaked lime and limestone powder.

Preferably, the step (1) may further comprise the step of maintaining the particle size of 0.002 ~ 0.5 mm by grinding the sulfate compound.

In the step (1), preferably, 20 to 45 parts by weight of slag may be further added to 100 parts by weight of the mixture.

According to another aspect of the present invention, the solidifying agent for organic / inorganic waste resources is prepared by the above-described manufacturing method.

Hereinafter, the present invention will be described in more detail.

In the method for producing an organic-inorganic waste resources solidifying agent according to an embodiment of the present invention, (1) 50 to 95% by weight of the sulfate compound and 5 to 50% by weight of the strong alkali-based powder, (2 ) Cooling the mixture and (3) refining the cooled mixture having a particle diameter of 2 mm or more and regrinding to a size of 0.002 to 2 mm.

In the step (1), 50 to 95% by weight of the sulfate compound and 5 to 50% by weight of the strong alkaline powder are mixed to prepare a mixture.

The sulfate compound used in the present invention is preferably calcium sulfate (CaSO ₄ ), potassium sulfate (K ₂ SO ₄ ), sodium sulfate (Na ₂ SO ₄ ), ferrous sulfate (FeSO ₄ ), ferric sulfate (Fe ₂ (SO _{4) 3} ) and one or more selected from the group consisting of hydrates thereof, more preferably ferrous sulfate. In addition, the strong alkali-based powder usable in the present invention preferably use any one or more selected from the group consisting of calcium oxide, magnesium oxide, calcium hydroxide, calcium carbonate, light dolomite, roadmite, cement, quicklime, slaked lime and limestone powder. It is preferable to use doromite, which more preferably includes calcium oxide and magnesium oxide and is advantageous for the reaction with sulphate compounding.

On the other hand, the strong alkali-based powder is 50 to 95% by weight of the sulfate compound and 5 to 50% by weight strong alkali-based powder. This is to maintain the pH of the solidification reaction with the organic and inorganic waste resources of 6 to 8, if the addition amount of the strong alkali powder than the weight ratio of the solidification reaction with the organic and inorganic waste resources pH value When the reaction proceeds at 6 or less, hydrogen sulfide gas is generated, and when the amount of addition of the strong alkali powder is higher than the weight ratio, the reaction proceeds at a pH of 8 or higher during the solidification reaction, so that ammonium ion (NH ₄ ⁺ ) in the sewage sludge is ammonia gas (NH ₃ ) it converts into basic odor gas such as ammonia gas.

In addition, the mixing ratio of the sulfate compound and the strong alkali powder may be appropriately mixed within the numerical range of the present invention according to the type and acidity of the organic and inorganic waste resources as reactants, and more specifically, a high basic oil such as sewage sludge. In the case of inorganic waste resources, the amount of sulphate compound is increased. On the contrary, in the case of high acidity organic and inorganic waste resources, a strong alkali powder is added.

On the other hand, as a preliminary step of the step (1) may further comprise the step of grinding the sulfate compound. In the case of ferrous sulfate, which is most suitable for the present invention, the sulfate compound contains about 40 to 60% by weight of water (FeSO ₄ · 7H ₂ 0, FeSO ₄ · H ₂ 0). It may have a form of, it is difficult to be mixed with the strong alkali-based powder. Therefore, it is necessary to grind it, in which case there is no particular limitation on the grinding method. Further, the particle size of the ferrous sulfate pulverized product is preferably 0.002 to 0.5 mm, more preferably 0.01 to 0.1 mm, and preferably ferrous sulfate recycled from the waste sulfate solution can be used.

In the step (2), the mixture mixed in the mixing step is cooled. In the step (1), when the ferrous sulfate and the strong alkali-based material is mixed, an acid-alkali reaction occurs and high temperature heat is generated. Therefore, the cooling step is required to terminate the reaction and to evaporate the water contained in the sulfate compound. . In this case, all conventional cooling methods such as a cooler or natural cooling can be used.

On the other hand, the mixture of the ferrous sulfate and the strong alkali-based powder that has undergone the heat dissipation step, the water content is evaporated to improve the hardness, some of which may have a lump form.

In the step (3), in order to maximize the efficiency of the solidifying agent, a particle diameter of 2 mm or more is selected from the cooled mixture and regrind to a size of 0.002 to 2 mm. In this case, if the particle diameter can be satisfied, the grinding time and the grinding method are not limited.

Hereinafter, looking at the reaction mechanism of the present invention in detail as shown in Scheme 1.

FeSO ₄ · 7H ₂ 0+ CaO ⇒ FeO + CaSO ₄ + 7H ₂ O (g) + _△ H

However, in the above FeSO ₄ · 7H ₂ 0 is an example of a representative sulfate compound, CaO is an illustration of a representative strong alkali material, and 7H ₂ O (g) means water contained in ferrous sulfate.

As can be seen in Scheme 1, the reaction mechanism of the present invention evaporates the water contained in the ferrous sulfate by acid alkali reaction. On the other hand, the heat of reaction is different depending on the reaction conditions, but generates approximately 220 ~ 250 ㎉ / mol.

When the solidifying agent of the present invention is added to an organic / inorganic waste resource, the solidifying agent reacts while being dissolved in the water of the organic / inorganic waste resource, thereby solidifying the organic and inorganic waste resource through high temperature heat generation. In other words, SiO ₂ and Al ₂ O ₃ forming colloids with clay particles of organic and inorganic waste resources are cured while causing a pozzolanic reaction with a hardening agent to enhance strength.

On the other hand, since the reaction proceeds at pH 6 to 8 as described above, the solidification reaction hardly occurs in the odor in the reaction step. In addition, the solidified organic and inorganic waste resources can be used as a solid material of the same form as the general soil by the oxidation function of the solidifying agent to cover landfills, decomposed soil and compost of landfills.

According to another embodiment of the present invention, a method for preparing an organic / inorganic waste resource solidifying agent, in the step (1), is preferably a stainless steel refining furnace slag 20 based on 100 parts by weight of a mixture of a sulfate compound and a strong alkali powder. 45 parts by weight may be further added.

The stainless refinery slag is a crystalline phase having a gamma-type dicalcium silicate crystal structure. In general, gamma type dicalcium silicate is gradually cooled from the hot melt phase to the crystal phase. This crystal phase transition is accompanied by volume expansion, and due to this volume change, a dusting phenomenon that collapses itself upon cooling occurs. Unlike the steel slag that occurs in general steel mills, such dusting produces very fine powder particles without a separate grinding process, so when it is used as a admixture added to a solidifying agent, pretreatment such as grinding is not necessary or less as with conventional admixtures. It is economical.

Stainless steel smelting furnace slag constituting the admixture of the present invention is used having a particle size of up to 250㎛, and is not intended to limit the particle size, more preferably 10-250㎛. The smaller the particle size of the stainless refining furnace slag is, the better, but in order to obtain a particle size of 10 μm or less, the stainless refining furnace slag must be pulverized again, and the specific surface area of the stainless refining furnace slag has a particle size of 250 μm or more. It is not suitable for use as an admixture for solidifying organic and inorganic waste resources because it is small and contains some stainless steel balls in the shape of beads.

The slag of the stainless steel refining furnace of the present invention reacts with the sulfate or alkali component of the solidifying agent to exist as OH ^- ions or SO ₄ 2 ^- ions. In this case, as in portland cement, the slag is hardened to form a crystal phase and harden. do.

Furthermore, the solidifying agent of the present invention promotes dissolution in the moisture of organic and inorganic waste resources to help the formation of crystalline phases, and increases the strength of the product as well as the water content in the organic and inorganic waste resources within a short time. Decreases.

On the other hand, preferably, 20 to 45 parts by weight of slag may be further added to 100 parts by weight of the mixture of the sulfate compound and the strong alkali powder. If the amount is less than 20 parts by weight, the effect of addition is insignificant. If it is more than 45 parts by weight, the solidification reaction exceeds pH 8, which may cause odor.

Through the following examples will be described the present invention in more detail. This example is intended to explain the present invention more specifically through the most preferred embodiments, and the scope of the present invention is not limited to these examples.

<Example 1>

1 kg of ferrous sulfate containing water was pulverized with a rod mill so that the average particle diameter was about 0.3 mm. 0.7 kg of a light dolomite powder was added to 1 kg of the ferrous sulfate pulverized product, followed by well stirring to prepare a mixture. After cooling for about 2 hours in a 4 ℃ cooler, the cooled mixture was regrind to a size of 1 mm average particle size to prepare a solidifying agent.

Comparative Example 1

A solidifying agent was prepared in the same manner as in Example 1 except that 50 g of light dolomite powder was added to 1 kg of ferrous sulfate pulverized product.

Comparative Example 2

A solidifying agent was prepared in the same manner as in Example 1 except that 1.1 kg of light dolomite powder was added to 1 kg of ferrous sulfate pulverized product.

<Example 2>

A solidifying agent was prepared in the same manner as in Example 1 except that 0.5 kg of slag was further added to the stainless steel refinery.

Comparative Example 3

A solidifying agent was prepared in the same manner as in Example 1 except that 0.25 kg of slag was further added to the stainless steel refinery.

<Comparative Example 4>

A solidifying agent was prepared in the same manner as in Example 1 except that 1 kg of slag was further added to the stainless steel refinery.

Meanwhile, the solidification agents prepared in Examples 1 and 2 and Comparative Examples 1 to 4 were reacted with sewage sludge (water content of 72.1%, pH 7.2) to measure the change in moisture content and odor level over time, and the results are shown in Table 1 below. Indicated. The degree of odor was measured by sensory evaluation by giving a score of 1 to 5 after 5 people absorbed (1 means no odor, 5 means very bad odor) was expressed by the average value.

Moisture content (%) Odor occurrence Example 1 42.9 1.8 Comparative Example 1 48.3 2.4 Comparative Example 2 47.1 3.7 Example 2 36.1 1.8 Comparative Example 3 42.0 1.8 Comparative Example 4 33.4 2.7

In Table 1, the water content represents the water content after 3 days of curing.

As can be seen in Table 1, compared with Example 1 satisfying the weight ratio of the present invention, the solidifying agents of Comparative Examples 1 and 2 that deviate from this, as well as the solidification efficiency with the sewage sludge, as well as severe odor occurred.

In addition, in Example 2, the addition of slag with the stainless steel refining showed more improved solidification effect, but when the amount less than the critical range of the present invention was added, the solidification effect was insignificant (Comparative Example 3). It can be seen that it occurs (Comparative Example 4).

The solidifying agent prepared according to the manufacturing method of the solidifying agent for organic / inorganic waste resources of the present invention hardly generates odor during the reaction step because the solidification reaction proceeds at a pH of 6 to 8 when reacting with the organic / inorganic waste resources. Excellent solidification efficiency.

In addition, the slag is added to the solidifying agent of the present invention in an appropriate ratio of stainless steel refining to exhibit more excellent effects. In addition, the solidified organic and inorganic waste resources can be recycled as cover material, dirty soil and compost, which is very advantageous in terms of resource recycling.

Although the present invention has been described in detail only with respect to the embodiments described, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical spirit of the present invention, and such modifications and variations belong to the appended claims. .

Claims (7)

In the method for producing a solidifying agent for organic and inorganic waste resources, (1) mixing 50 to 95% by weight of the sulfate compound with 5 to 50% by weight of the strong alkali powder; (2) cooling the mixture; And (3) A method for producing a solidifying agent for organic / inorganic waste resources, characterized in that the cooled mixture comprises the step of selecting a particle diameter of 2 mm or more and regrinding to a size of 0.002 to 2 mm. The method of claim 1, The organic / inorganic waste resources solidifying agent for organic / inorganic waste resources is any one selected from the group consisting of sewage sludge, purified water sludge, food waste, livestock waste, waste gypsum, waste lime and dredged soil. Manufacturing method. The method of claim 1, The sulfate compound is calcium sulfate (CaSO ₄ ), potassium sulfate (K ₂ SO ₄ ), sodium sulfate (Na ₂ SO ₄ ), ferrous sulfate (FeSO ₄ ), ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) and hydrates thereof A process for producing the solidifying agent for organic / inorganic waste resources, characterized in that at least one selected from the group consisting of. The method of claim 1, The strong alkali-based powder is any one or more selected from the group consisting of calcium oxide, magnesium oxide, calcium hydroxide, calcium carbonate, light dolomite, roadmite, cement, quicklime, slaked lime and limestone powder. Process for producing a solidifying agent for resources. The method of claim 1, Grinding the sulfate compound before the step (1) to maintain the particle size of 0.002 ~ 0.5 mm The manufacturing method of the solidifying agent for organic-inorganic waste resources, characterized in that it further comprises. The method of claim 1, The method of producing a solidifying agent for organic-inorganic waste resources, characterized in that 20 to 45 parts by weight of the slag of stainless steel refinery is added to 100 parts by weight of the mixture in the step (1). A solidifying agent for organic / inorganic waste resources, which is produced by the process according to any one of claims 1 to 6.