KR100464666B1 - Solidificator Manufacturing Method with Waste Oyster Shell - Google Patents

Abstract

The present invention relates to a method for producing a ground-improved solidified fire using the oyster shell, the step of washing the oyster shell to remove the salt, crushing the salt removed oyster shell, the classification to powder the crushed oyster shell to a predetermined particle size Step, calcination step of burning oyster shell powder to remove carbon dioxide to produce quicklime (calcium oxide), reacting the produced ash produced in the calcination step with water to produce hydrated lime (calcium hydroxide), fly ash or quicklime lime ( , ) And plaster ( ), Mixing with blast furnace slag, etc., can reduce environmental pollution by recycling oyster shells, and can be used as a building material for improvement of soft ground, tunnel, underground public filling of abandoned mines, and partially replace natural cement. In addition to saving money, it is possible to solidify the sludge, scavenger and sludge of sewage water to reduce environmental pollution.

Description

Solidificator Manufacturing Method with Waste Oyster Shell}

The present invention relates to a method for manufacturing a solid fire, in particular, to replace the limestone by recycling the oyster shell and to react with other mixed raw materials to improve the ground or to use as a filler of underground cavity, and the oyster shell that can solidify the sludge of sewage water It relates to the ground improvement type fire used.

In general, solidified materials serve as a catalyst for solidifying materials, and are added to soft ground to form solid improved pillars in the ground to strengthen the ground, or solidify harmful wastes, such as heavy metals contained in the water. It does not harm the groundwater or soil, or makes it difficult to dissolve.

Limestone used in such fires has limited resources and open-pit mining, severe natural damage and high quality limestone are already depleted. Therefore, it is urgent to develop limestone substitute raw materials for cutting and environmental protection. to be.

On the other hand, oyster shells, a by-product of oyster farming, are illegally dumped and have a problem of harming the coastal environment. However, they are only used as crushed stone, calcareous fertilizer, and animal feed.

Accordingly, the present invention has been made to solve the problems described above, by manufacturing lime as a raw material of oyster shell and manufacturing a solid material using the lime can reduce the raw material cost and prevent environmental pollution as well. In addition, the purpose is to provide a ground-improved solidified fire using oyster shells that can be expected to replace the natural lime.

The present invention for achieving the above object, the salt removal step, the grinding step, the classification step, the calcination step of burning oyster shell powder to remove quick carbon dioxide (calcium oxide) to produce the produced, produced in the firing step Reacting lime with water to produce hydrated lime (calcium hydroxide), fly ash or hydrated lime , ) And plaster ( ), Blast furnace slag and mixing step.

Therefore, according to the present invention, it is possible to manufacture an environmentally friendly solidified material which can improve the ground and solidify the wastewater sludge by using the pozzolanic reaction and the ettringite reaction.

1 is a flow chart showing a method of manufacturing a solid fire using the oyster shell according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart showing a method of manufacturing a solid fire using the oyster shell according to the present invention.

The present invention according to the above drawings, the step of washing the oyster shell to remove the salt, the step of crushing the oyster shell with salt removed, the classification step of powdering the crushed oyster shell to a predetermined particle size, burning the oyster shell powder to burn carbon dioxide Firing step of removing quicklime (calcium oxide) by removing, reacting the produced ash produced in the firing step with water to generate slaked lime (calcium hydroxide), fly ash (quick lime or slaked lime) , ) And plaster ( ), Blast furnace slag and mixing step.

The above method is characterized in that it is used as a ground improvement work to improve the soft ground, tunnels, fillers for underground joints of abandoned mines, and the like.

Oyster shells are composed of calcium carbonate The main component and mineral phase are the same as natural limestone, making it available as a solidified material.

The desalination step collects oyster shells and washes them with water to remove chlorine anions ( ) To remove odors and dust during cleaning.

The crushing step is a process of crushing to a size suitable for processing the oyster shell after the desalination step.

The classification step is a process of pulverizing the crushed oyster shell to a predetermined particle size.

The firing step is to burn oyster shell powder to produce calcium oxide or calcium hydroxide.

Here, the process of manufacturing the ground-improved solidified material using calcined calcium oxide or calcium hydroxide,

First, the ground improvement is to remove or reduce the harmful behavior of the ground that may occur after construction or completion when constructing the structure in advance. When the ground is improved by the above method, the oyster shell ( ), Blast furnace slag, fly ash, gypsum and the like are mixed and used.

The blast furnace slag is a rocky material mixed with impurities of iron ore during the blast furnace work at the steel mill. , It is a substance suspended in a molten state at high temperatures in combination with a fly ash. Fly ash is a fine particle of ash contained in a gas from a boiler of a coal-fired power plant. ) And aluminum oxide ( ) And gypsum, ) Is a by-product of phosphate from fertilizer plants.

Fired angle ) Is a fly ash ( ) And plaster ( ) And Ettringite reaction to produce a solid material.

The chemical formula representing this is as follows.

+ + + -→ ㆍ ㆍ ㆍ

That is, since hydration produces needle-like crystals called ettringite, which reduces porosity, it reduces cracks due to dry shrinkage of concrete and has long-term strength improvement and waterproofing effect.

Fired angle , ) Is a fly ash ( ) And plaster ( ) And iron oxide ( ) And the pozzolan reaction to produce a solid material.

The chemical formula is as follows.

ㆍ ㆍ + + +

-→ ㆍ ㆍ ㆍ + ㆍ ㆍ ㆍ

In other words, pozzolanic is not cementitious by itself, but calcium hydroxide ( ) To form CSH.

Blast furnace slag causes latent hydraulic reaction when present with cement and water, and fly ash has no hydration reaction on its own but soluble silica ( ) Is slowly reacted with calcium hydroxide produced during cement hydration at room temperature to produce insoluble stable calcium silicate hydrate, and improves workability and pumpability, and the amount of cement added to the cement It can reduce usage.

Calcium oxide or calcium hydroxide produced from oyster shells is silica ( ) And alumina ( ) Is used in the synthesis of calcium silicate-based building materials by hydration with siliceous raw materials having a ratio of 6: 1 or more, and can be used as a raw material superior to limestone.

The process of the invention can also be used to solidify sewage sludge.

Solidification is the addition of a sufficient amount of solids, including solids, to toxic substances, resulting in the formation of solids. Solidification treatments for the prevention of environmental pollution include heavy metals contained in hazardous wastes. Water) to harm the groundwater or soil, or to change it into a form that is difficult to dissolve.Inorganic solidifying materials are usually cement-reactive, causing chemical reactions between pollutants and solidifying materials Suitable for solidifying heavy metals).

(Example)

The oyster shells collected from the coast are washed with water to remove foreign substances, pulverized to a particle size of 2 mm or less, and calcined by heating to 600 ° C to 900 ° C to prepare quicklime.

The following table shows the state before raw materials are put into the mixing stage.

[1] quicklime (raw materials from oyster shells)

division Characteristics of quicklime using shell Adult and Mountain Tongyeong, Gyeongnam, South Coast of Jeolla-do chief ingredient Calcium Carbonate (CaCO ₃ ) Categories and Particles Powder level: 2400cm ² / g or more, Salinity: 1% or less Ignition loss: 5% or less, Calcium oxide: 45% or more

[2] slags

division Slag properties Adult and Mountain Steelmaking and Steelmaking Process chief ingredient SiO ₂ , CaO Categories and Particles Powder level: 3000cm ² / g or more, Salinity: 1% or less Loss on ignition: 5% or less,

[3] fly ash

division Characteristics of Fly Ash Adult and Mountain Thermal power plant, by-product of steel mill chief ingredient SiO ₂ , Al ₂ O ₃ Categories and Particles Powder level: 2400cm ² / g or more, Loss on ignition: 5% or less, SiO ₂ : 50% or more

[4] plaster

division Characteristics of plaster Adult and Mountain By-products of Phosphate and Fertilizer Manufacturing Process chief ingredient CaSO ₄ Categories and Particles Powder level: 2400cm ² / g or more, Loss on ignition: 5% or less, SO ₃ : 50% or more

The manufacturing process and construction process of the ground-improved solidified material using the oyster shell of the present invention using the utilized quicklime and blast furnace slag, fly ash, gypsum is shown in Figure 1 and below.

Proper blending ratio to be achieved in the present invention based on the total weight of the solidified composite as a weight ratio 100, the weight ratio of oyster shell quicklime is 40 to 60 degrees, the slag weight ratio is 40 to 60 degrees, the weight ratio of gypsum 5 to 20, The fly ash weight ratio is 4 to 20.

Moisture adjustment is determined by the water content of the soil. According to the water content, uniaxial compressive strength, and bearing capacity of the soil to be applied, an example of selecting the amount of addition and applying it to the construction site is as follows.

◆ Test result of solidification treatment of sewage sludge

1. Conditions for the target soil (sewage sludge) before solidification

division Sample 1 Sample 2 Sample 3 Sample 4 standard PH 6.0 6.2 6.0 6.1 Water content (%) 88.8 88.3 89.1 88.7 burglar?? 0 Weighting 1.55 1.44 1.49 1.43 Ignition loss 53.2 55.6 54.9 53.2

2. Test result after solidification treatment of sewage sludge

division Sample 1 Sample 2 Sample 3 Sample 4 standard PH 6.0 6.2 6.0 6.1 Uniaxial compressive strength (㎏ / ㎠) 0.7 0.8 1.2 1.1 0.3 Water content (%) 53.2 55.6 54.9 53.2

3. Test result after solidification treatment of sewage sludge 7 days

Sample 1 Sample 2 Sample 3 Sample 4 standard PH 12.06 12.26 11.90 12.10 Bearing capacity (CBR _5.0 ) 8.03 7.76 6.55 5.50 5.0 Uniaxial compressive strength (㎏ / ㎠) 1.6 1.4 1.5 1.3 0.3 Water content (%) 33.0 32.1 34.3 30.1

◆ Heavy Metal Dissolution Test Results

1. Sludge Before Solidified Fire Treatment

division Sludge 1 Sludge 2 Sludge 3 Sludge 4 Below standard (ppm) AS 0.20 0.16 0.26 0.22 1.50 Cr Not detected Not detected Not detected Not detected 1.50 Pb 0.34 0.32 0.07 0.29 3.00 CD 0.01 0.01 Not detected 0.01 0.03 Cu 0.22 0.33 0.06 0.21 3.00 Hg Not detected Not detected Not detected Not detected 0.005 CN Not detected Not detected Not detected Not detected 1.00

2. Dissolution test result of solid heavy metal after solidified fire

division Sludge 1 Sludge 2 Sludge 3 Sludge 4 Below standard (ppm) AS 0.23 0.16 0.20 0.13 1.50 Cr Not detected Not detected Not detected Not detected 1.50 Pb 0.04 0.03 0.07 0.04 3.00 CD Not detected Not detected Not detected Not detected 0.03 Cu 0.21 0.13 0.16 0.01 3.00 Hg Not detected Not detected Not detected Not detected 0.005 CN Not detected Not detected Not detected Not detected 1.00

The manufacturing method of the present invention can be used to manufacture construction materials by solidification and solidification, Low content of silicic acid ( The higher the content of c), the softer it is to be calcined, and when a certain amount of clay or silica is added, it can be used as a main raw material for general softening.

As described above, according to the solidified material manufacturing method using the oyster shell according to the present invention, it is possible to reduce the environmental pollution by recycling the oyster shell, can be used as a building material, such as soft ground improvement and fillers for the ground joint, part of the natural cement In addition to saving resources, it is possible to solidify the sludge of sewage water, thereby reducing the environmental pollution.

Claims (4)

Washing the oyster shell to remove salt; Crushing oyster shells from which salt is removed; A classification step of powdering the crushed oyster shell into a predetermined particle size; Firing the oyster shell powder at a temperature of 600 ° C. to 900 ° C. to remove carbon dioxide to generate quicklime (calcium oxide); 40 to 60 parts by weight of quicklime, fly ash ( , 4-20 parts by weight, gypsum ( ) 5 to 20 parts by weight, blast furnace slag 40 to 60 parts by weight of the mixing step of mixing the mixing ratio; delete delete delete