KR100521454B1 - Manufacture method of calcium silicate plate using seawater magnesia waste as lime raw material - Google Patents

Abstract

The present invention relates to a method for producing a calcium silicate plate having excellent light-weight fire-retardant effect by using seawater magnesia waste as a calcium raw material of calcium silicate plate.

The present invention for this purpose is a wet sieve with a mesh of 200 mesh to an average particle size of 5 ~ 10 ㎛, 200 mesh (75 ㎛) or more particle size distribution of less than 2% by weight, CaO content of more than 75% by weight of seawater magnesia manufacturing process It provides a method for producing calcium silicate plate using the waste generated from the lime as raw material.

Calcium silicate plate prepared using the seawater magnesia waste of the present invention as a raw material for lime, has a lower specific gravity and higher strength than the calcium silicate plate prepared using only lime as a raw material for lime, and when manufactured as a building interior material including a ceiling material Seawater magnesia waste can be recycled.

Description

Manufacturing method of calcium silicate plate using seawater magnesia waste as a raw material of lime

[Industrial use]

This invention is a manufacturing method regarding the calcium silicate board using seawater magnesia waste. In particular, the present invention relates to a method for producing a calcium silicate plate having excellent light-weight fire-retardant effect by using seawater magnesia waste as a calcium raw material of calcium silicate plate.

[Prior art]

Calcium silicate plate, widely used as interior and exterior building materials, disperses lime raw materials such as hydrated lime or quicklime and siliceous raw materials such as diatomaceous earth or silica powder together with reinforcing fibers such as asbestos, etc. The green sheet is manufactured by hydrothermal reaction at high temperature and high pressure in an autoclave and dried.

The most important physical properties in the manufacture of calcium silicate plates are specific gravity and strength. The specific gravity and strength of the calcium silicate plate is determined as a raw material of lime and silicate. These raw materials are dispersed in water and partially dissolved to form CSH gel, which is an intermediate of calcium silicate. Molding specific gravity becomes low and strength becomes high. The reason for this is that the calcined raw material is larger in water with low solubility in water, and the siliceous raw material is large in water with high temperature, and the CSH gel is formed by the reaction of dissolved lime and siliceous raw material. The volume of the gel is large. If the weight volume of the CSH gel is large, it has a high thickness at the same pressure during molding, and thus the specific gravity of the final product is lowered. If a large amount of CSH gel is formed, the hydrothermal reaction, which becomes tobermorite, proceeds well and is high in strength. Will be displayed.

It is primarily a siliceous raw material to increase the weight ratio of such C-S-H gel. Diatomaceous earth, which is widely used as a siliceous raw material for calcium silicate plates, contains about 70% or more of amorphous SiO 2 and is a raw material that swells in water at 80 to 100 ° C. in the presence of alkali. Therefore, when diatomaceous earth is used as a siliceous raw material, the C-S-H gel is well formed and the specific gravity during molding is lowered, and the hydrothermal reaction proceeds well.

However, the generation of calcium silicate is proceeding the reaction by using an amorphous SiO ₂ as a siliceous material is CSH gel → CSH (Ⅱ) → CSH ( Ⅰ) → crude Notre light and proceeds to (xonotlite), whereas the siliceous material in a crystalline SiO ₂ The reaction progresses to CSH gel → CSH (II) → CSH (I) → tobermorite → xonotlite. Therefore, when diatomaceous earth, in which amorphous SiO ₂ is the main component, is used as a siliceous raw material of the calcium silicate plate, the final calcium silicate property is tobomorite, and thus there is a problem in generating a final reaction.

To supplement this, alumina (Al ₂ O ₃ ) is attached. Alumina is a substance that increases the production of tobomorphite because it interferes with the production of zonolite in the production of calcium silicate. It is also present as an impurity of diatomaceous earth and sometimes added to raw materials in the manufacture of calcium silicate, but its content is usually used within 3% by weight.

However, the presence of alumina in the calcium silicate plate helps the transition to tobomorite, but there is a problem of increasing the specific gravity of the volume and lowering the strength. In order to compensate for this, as well as amorphous diatomaceous earth as a siliceous raw material, silica powder containing crystalline SiO ₂ as a main component may be added to transfer to tobomolite without using alumina.

These silica powders help the transition to tobomorite, but the formation of C-S-H gels is slower than that of diatomaceous earth, and therefore, an appropriate mixing ratio is required for the application of siliceous material.

However, silica powder or diatomaceous earth has a lot of components (soluble SiO ₂ ) that are well soluble in water, or if such conditions are made, the CSH gel is well formed, and the hydration reaction proceeds well.

The secondary material that increases the weight ratio of the CSH gel is the calcareous raw material. Lime raw material of calcium silicate plate is calcined lime (CaO) produced by calcining limestone (CaCO ₃ ) at a temperature of about 1,000 ° C. or higher, or calcined lime [Ca (OH) ₂ ] produced by reacting this lime with water. It is a raw material.

In order to increase the weight volume of the C-S-H gel, the calcareous raw material must be dissolved in water and react with the siliceous raw material. However, the slaked lime obtained by digesting the limed lime or quicklime, which is a raw material of lime, is well dissolved in cold water, and the solubility decreases as the temperature of water rises. Therefore, the management of the particle size of the calcareous raw material is more important because diatomaceous earth conflicts with the need for hot water to swell.

According to the above contents, the reaction of the calcareous raw material and the siliceous raw material to the C-S-H gel depends on the particle size, purity, and impurities, and it can be seen that it is necessary to manage their reaction conditions.

On the other hand, seawater magnesia used as a refractory material reacts magnesium ions (Mg ⁺⁺ ) in seawater with slaked lime [Ca (OH) ₂ ] to produce magnesia [Mg (OH) ₂ ]. However, in the manufacturing process, waste that is mainly composed of unreacted slaked lime is generated, and this waste, which is mainly composed of slaked lime, is difficult to regenerate and use again due to the inflow of seaweed, and excessive treatment costs are required to treat such waste. As a result, the cost of seawater magnesia increases.

Therefore, it is expected that the calcium silicate plate may be manufactured by using the waste which is mainly composed of slaked lime produced in seawater magnesia as the raw material of calcium silicate plate, but the seawater magnesia waste is produced by the carbon dioxide gas in the seawater. Since the slaked lime is added to remove the slaked lime, which is precipitated after reacting with magnesium ions and carbon dioxide, it is difficult to use the waste itself as a raw material of lime because the particle size of the waste is not constant because it is introduced into the seaweed at the time of collection. In fact, the calcareous raw material of the calcium silicate plate is difficult to react with the siliceous raw material because it must be in the form of small fine particles of at least 600 mesh or less.

Therefore, there is a need for a method of controlling the particle size of seawater magnesia waste and using it as a raw material of calcium silicate.

Therefore, the present invention is to provide a method for producing a calcium silicate plate exhibiting excellent strength and light weight by using the waste, which is a main component of the lime produced in seawater magnesia, as a raw material of calcium silicate, by controlling the particle size.

[Means for solving the problem]

In order to achieve the above object, the present invention controls the particle size by wet sifting waste generated in seawater magnesia manufacturing process, and a method for producing calcium silicate plate using the waste of which the particle size is controlled as a lime material of calcium silicate plate To provide.

The present invention also provides a blending ratio of the raw material slurry in which the calcium silicate plate can exhibit more excellent physical properties.

The present invention for this purpose is a wet sieve with a mesh of 200 mesh, the average particle size of 5 ~ 10 ㎛, 200 mesh (75 ㎛) or more particle size distribution of less than 2% by weight, CaO content of 85% by weight or more seawater magnesia manufacturing process It provides a method for producing calcium silicate plate using the waste generated from the lime as raw material.

In addition, the following raw material slurry formulation ratio is provided when wastewater generated in the seawater magnesia manufacturing process is used as a calcined raw material of calcium silicate plate.

a) 1000 to 2000 parts by weight of water;

b) 10 parts by weight of pulp;

c) 5 parts by weight of asbestos;

d) 25 parts by weight or less of slaked lime;

e) 5-30 parts by weight of seawater magnesia waste;

f) 30 parts by weight of diatomaceous earth;

g) 20 parts by weight of silica;

h) 2.5 parts by weight of sepiolite;

i) 2.5 parts by weight of wollastonite; And

j) 2 parts by weight or less of alumina cement;

It includes.

Seawater magnesia waste is a waste, and when it is first produced, it is about 10% by weight of a particle size of 200 mesh or more when wet sifting into a 200 mesh network. If the particle size of 200 mesh or more is 2% by weight or more, the calcium silicate plate of the present invention has a tendency to increase in density and low reactivity and thus to decrease in strength.

The particle sized seawater magnesia waste of the present invention has a content of 78.59 wt% CaO, 9.20 wt% MgO, 1.15 wt% Al ₂ O ₃ , 0.57 wt% Fe ₂ O ₃ , and 10.49 wt% SiO ₂ . The composition of Al ₂ O ₃ is 3 wt% or less, which indicates that the transition to tobomorite can proceed well.SiO ₂ is about 10% or more, which is introduced from the sea sand, and its properties are crystalline SiO ₂ . Since it is quartz and is a soluble SiO ₂ form, the CSH gel is well formed, and the transition to tobomorite, the calcium silicate hydrate of the present invention, is well performed.

However, when the CaO content of the seawater magnesia waste having a controlled particle size is 75% or less, the hydrothermal reaction of the present invention is not well performed, thereby reducing the strength of the final calcium silicate plate.

The raw material slurry of the present invention can be used together as a calcareous raw material including slaked lime. In general, hydrated lime used as a calcareous raw material for calcium silicate plates is preferred, made from soft burned quicklime, and more preferably using a 325 mesh (45 μm) tradition. In the present invention, it was shown that the use of seawater magnesia waste as the raw material of calcium silicate plate lowers the density of the final calcium silicate plate than that of the general lime.

In the raw material slurry formulation, the pulp is a reinforcing fiber, any kraft pulp can be used, and serves as a dispersant for asbestos, which is another reinforcing fiber raw material.

Asbestos uses grade 5 crysotile white asbestos. The use of asbestos grade 5 or lower lowers the strength and reduces the powder retention during molding.

In the raw material slurry blend, diatomaceous earth is a siliceous raw material, an average particle size of 10 to 20 µm, a particle size distribution of 325 mesh (45 µm) or more is 2% by weight or less, and an SiO ₂ content of 70% by weight or more.

In addition, the silica powder has an average particle size of 5 to 10 µm, a particle size distribution of 400 mesh (37 µm) or more, 2 wt% or less, and a SiO2 content of 90 wt% or more.

Wollastonite is a fibrous filler in the raw material slurry formulation, and the aspect ratio (length: thickness ratio) is preferably at least 8: 1 or more, and the average particle size is 75 μm (200 mesh).

Sepiolite (sepiolite) is a fibrous filler, the average particle size is preferably 75 ㎛ (200 mesh).

Alumina cement is extrapolated and increases in specific gravity above 2.0% by weight.

The raw materials are sequentially dispersed in water, and the prepared slurry has 5 to 10% by weight of solids, and the prepared slurry is 4 to 6 ply in a circular net evaporator equipped with 4 to 6 vat. Formed into a green sheet (green sheet), the formed green sheets were stacked one by one on a 50 basis, and then hydrothermally reacted for 8 to 10 hours at a reaction temperature of 180 ° C. and a reaction pressure of 10 kg / cm 2 in an autoclave. The reacted calcium silicate plate is naturally dried by latent heat of an autoclave or forcedly dried at 100 ° C. or higher to prepare a calcium silicate plate having a water content of 5 to 20% or less.

The calcium silicate plate of the present invention has the high orientation as it has in a general ring network agitator.

When measuring the physical properties of the calcium silicate plate prepared above is carried out after drying the content at 100 ℃ or more.

The calcium silicate plate thus prepared has a specific gravity of about 0.74 to 0.85, and exhibits a physical property of 0.8 CK of the KS standard, and exhibits physical properties equal to or higher than those of a calcium silicate plate prepared using only conventional lime as a raw material for lime. Indicates.

Specific strength is the conversion value of strength to specific gravity, which is the value of bending strength divided by density ² .

The present invention will be described in detail with reference to the following Examples, which are intended to illustrate the present invention, but the present invention is not limited thereto.

EXAMPLE

Examples 1-8, Comparative Example

A raw material slurry having a solid content of 5% by weight was prepared by the formulation as shown in Table 1, and the raw material slurry was subjected to an initial molding in a ring network agitator having a VAT number of 6 to prepare a 4-ply green sheet. 50 sheets of green sheets were stacked and loaded into an autoclave and subjected to hydrothermal reaction for 8 hours at a reaction temperature of 180 ° C. and a reaction pressure of 10 kg / cm 2. Calcium silicate plate was produced. The physical properties of this calcium silicate plate are shown in Table 1.

TABLE 1

division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative example Compounding (wt%) Seawater Magnesia Waste 5 10 20 25 30 30 30 30 0 Slaked lime 25 20 10 5 0 0 0 0 30 Diatomaceous earth 30 30 30 30 30 30 30 30 30 Silica powder 20 20 20 20 20 20 20 20 20 asbestos 5 5 5 5 5 5 5 5 5 Sepiolite 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Wallacetonite 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 pulp 10 10 10 10 10 10 10 10 10 Alumina cement 0.5 0.5 0.5 0.5 0.5 2 1.0 0 0 water 200 200 200 200 200 200 200 200 200 Properties Density (g / cm 3) 0.79 0.77 0.77 0.76 0.78 0.83 0.79 0.74 0.80 Bending strength (kgf / ㎠) 121 118 119 121 120 131 122 101 117 Specific Strength (Bending Strength / Density ² ) 194 199 201 209 197 190 195 184 182 Fireproof Flame retardant class 1 Flame retardant class 1 Flame retardant class 1 Flame retardant class 1 Flame retardant class 1 Flame retardant class 1 Flame retardant class 1 Flame retardant class 1 Flame retardant class 1

Calcium silicate plate prepared using the seawater magnesia waste of the present invention as a raw material for lime, has a lower specific gravity and higher strength than the calcium silicate plate prepared using only lime as a raw material for lime, and when manufactured as a building interior material including a ceiling material Seawater magnesia waste can be recycled.

Claims (7)

In the method for producing a calcium silicate plate, a) preparing a raw material slurry by dispersing a lime material, a siliceous material, a reinforcing fiber and a filler together with particle size controlled seawater magnesia waste; b) forming the green sheet by molding the raw material slurry by a circular net evaporation method; c) curing the green sheet by hydrothermally reacting the molded green sheet at high temperature and high pressure in an autoclave; And d) drying the cured green sheet to produce a calcium silicate plate How to include. The method of claim 1, The particle size controlled seawater magnesia waste is included in the raw material slurry 5 to 30% by weight based on solids. The method of claim 1, The particle size controlled seawater magnesia waste is produced by wet sifting the waste generated in the seawater magnesia manufacturing process with a mesh of 200 mesh. The method of claim 1, Method for controlling the particle size of the seawater magnesia waste has an average particle size of 5 ~ 10 ㎛. The method of claim 1, At least 200 mesh (75 μm) particle size of the particle size controlled seawater magnesia waste is 2% by weight or less. The method of claim 1, The CaO content of the particle size controlled seawater magnesia waste is at least 75% by weight. The method of claim 1, Raw material slurry containing the calcined raw material of the seawater magnesia wastes a) 1000 to 2000 parts by weight of water; b) 10 parts by weight of pulp; c) 5 parts by weight of asbestos; d) 25 parts by weight or less of slaked lime; e) 5-30 parts by weight of seawater magnesia waste; f) 30 parts by weight of diatomaceous earth; g) 20 parts by weight of silica; h) 2.5 parts by weight of sepiolite; i) 2.5 parts by weight of wollastonite; And j) 2 parts by weight or less of alumina cement by extrapolation How to include.