KR101289807B1 - Method for manufacture of fire-resistant MgO-board from serpentine powder - Google Patents

Abstract

The present invention manufactures activated fine powder by mechanochemical milling method using serpentine ore which has no special use other than steelmaking magnesium oxide (MgO) raw material, and replaces expensive MgO imported, thereby producing a lightweight non-flammable magnesium oxide board It is about. In particular, the invention can recycle the entire amount of fine powder for steelmaking that is discarded by drying and pulverization from the generated state.The effect of manufacturing high value non-combustible materials through resource recycling at the same time as developing new use of serpentine by replacement of steel by-products. Has

Description

Production of fire-resistant MgO-board from serpentine powder using serpentine by mechanochemical method

The present invention manufactures activated fine powder by mechanochemical milling method using serpentine ore which has no special use other than steelmaking magnesium oxide (MgO) raw material, and replaces expensive MgO imported, thereby producing a lightweight non-flammable magnesium oxide board It is about. In particular, the invention is to recycle all of the serpentine fine powder discarded and produced by the drying and pulverization from the generated state, and to develop a new use of the serpentine by replacing the steel by-products and to manufacture high value non-combustible materials through resource recycling. Has an effect.

On the other hand, serpentine is a hydrous silicate mineral composed of 35 to 38% magnesium oxide (MgO) and 35 to 40% silicon dioxide (SiO ₂ ), which is mostly buried in Andong, Gyeongnam Ulsan, and Hongseong, South Korea. have. Domestic reserves are estimated at around 75 million tons.

Serpentine can be prepared by high acid amorphous silica with 20 ~ 40Å pore and tens to hundreds of m2 / g specific surface area by removing impurities such as MgO, Fe ₂ O ₃ , Al ₂ O ₃ , CaO by appropriate acid treatment method. The porous silica material with excellent reactivity and adsorption can be used as an additive in food and beverage process, water treatment, paint, tire, etc. Also, it is easy to manufacture various silicon base materials and develop new material manufacturing technology such as water glass and zeolite synthesis. There are possible advantages.

In Korea, however, serpentine, which satisfies the domestic demand of all major non-metallic minerals, has abundant reserves and supplies about 650,000 tons / year mainly to Pohang and Gwangyang steelworks as MgO source for steel slag forming agent at low price. It has a simple market structure. In addition, there is no research on the development of technology for manufacturing industrial raw materials using serpentine.

Meanwhile, in developed countries, many studies have been conducted on the use of serpentine for a long time, and the development of land reforming agents from chrysotile asbestos, and the development of technologies for use as synthetic raw materials such as zeolite, silicon carbide, calcium silicate hydrate and fluor-mica. And research results such as development of manufacturing technology of magnesium compound.

All of these serpentine is expected to be reduced due to the problem of asbestos in process, and the large amount of discarded microparticles is not finding any other use, and it is subject to great restrictions on the use of building materials, aggregates, etc. Due to dust generation, there are many problems due to anxiety such as safety and user's avoidance of use.

On the other hand, gypsum board, which is currently used for wall and partition filling, is used in the form of mixing admixtures with gypsum to form a plate, and then attaching paper to upper and lower surfaces. Should be dealt with. Also, gypsum, the main raw material, absorbs a large amount of moisture and strengthens the strength of the board, which is attached to the upper and lower surfaces, but also has low resistance to moisture and cannot be used in moist areas. There are many problems in use when it is weak and needs to be processed to attach screws or other materials when used for walls. Accordingly, there has been a demand for the development of a new building non-combustible board having excellent strength, non-combustibility, and water resistance that can replace the existing gypsum board.

Conventional panels other than gypsum board have been used as the main binder of organic resins such as melamine resin, and the amount of addition is required at least 10% or more. Such a conventional panel has limitations in heat resistance and fire resistance due to the nature of organic matter, there is a risk of the generation of toxic gas in the event of a fire, and has the disadvantage of not maintaining the strength of the plate at high temperatures. Therefore, magnesium oxide board, a new building panel, has been developed and manufactured to complement the problems and points of strength and heat resistance performance. Magnesium board is a product that is compression-molded with magnesium oxide (MgO) which has incombustibility, fire resistance, waterproofness and heat retention as a main component, which can minimize the loss of life and material damage caused by fire, and shrink and expand due to temperature and moisture. It can be used semi-permanently by preventing it. It is a panel manufactured to contribute to the long life of the building and the weight reduction of the building. In general, magnesium oxide has a high melting point (2800 ° C.), excellent base resistance and electrical insulation at high temperatures, high coefficient of thermal expansion and thermal conductivity, and particularly high light transmittance and low cost. For this reason, it is widely used as a heat resistant material, a high temperature insulation material, high temperature optical, and an illumination material.

Magnesium board is composed of water, wood flour or pearlite, magnesium oxide (MgO) and magnesium chloride

It is known that (MgCl ₂ ) is a main component and various fibers are added as reinforcing materials.

However, due to the ubiquity of the origin of magnesium oxide raw materials and the introduction of the quota system for the protection of local resources, the price of raw materials is so high that it is impossible to manufacture them in Korea. As a result, the company has devised a way to replace high-purity MgO and utilize low-cost serpentine that can be procured in Korea.

Accordingly, the inventors found that activating and using serpentine to generate serpentine for the purpose of creating serpentine uses by researching in various aspects of development of the use, and the inventors found that it is an essential process for MgO substitution, which is the main raw material of magnesium board. The invention was conceived.

Therefore, the present inventors dry the serpentine, pulverize it in a rotary furnace, activate it using a raymond mill or centrifugal vibration mill to induce surface activation by a recently proposed mechanochemical reaction, and adjust the particle size of the nonflammable lightweight wall magnesium. It was intended to be used as a (MgO) oxide substitute.

Therefore, in the present invention, the magnesium board having excellent physical properties and fire retardant performance was manufactured by replacing expensive magnesium oxide with serpentine which is a low-cost domestic resource.

The serpentine powder is used as a substitute for the expensive MgO used in the magnesium oxide board for lightweight walls, considering that the serpentine is produced as a crystalline substance, and it becomes an organic substance that is easy to react when given the pulverization process and the mechanical and chemically appropriate active conditions. The present invention has been invented a process that goes through drying, processing, grinding, activation, mixing, molding and curing.

In order to replace some or all of the expensive magnesium oxide with by-product and inexpensive serpentine, the present invention is used to dry the serpentine and then pulverize it in a ball mill, and then use a mechanical chemical grinding activation using a vibration centrifugal mill and a raymond mill, and then adjust the particle size. It provides a process technology for manufacturing magnesium oxide board by making activated fine powder, mixing, molding and curing with other existing additives.

In order to achieve the object of the present invention is characterized in that it is activated by introducing a drying process for removing water from the serpentine in the process and a process such as a fine ball mill grinding, centrifugal vibration mill and raymond mill to impart mechanochemical reaction characteristics.

Preferably, the process consists of a combination of four to five unit processes according to the type of the additive when mixing the additive during the process. When grinding, serpentine is used by grinding with a centrifugal vibration mill and raymond mill having mechanochemical functions so that the average particle size is 100 mesh or less. When the serpentine fine powder is used as an organic resin as a binder, it is used as a substitute for simple magnesium oxide (MgO), or when magnesium chloride is added as a solidifying agent, up to 10 to 90 weight percent of MgO is added. Pozzolanic reactions result in the formation of magnesium hydrate (5 Mg (OH) ₂ · MgCl ₂ · 8H ₂ O) in the magnesium board, thereby enhancing its strength.

As described above, by replacing some or all of the expensive magnesium oxide, which is the basic material of the magnesium board, which is a non-combustible lightweight building material, with serpentine, it is possible to produce functional materials and high value materials through the import substitution effect of expensive resources and utilization of low cost resources. Economically great effect.

Figure 1 is a process of activation grinding and magnesium oxide board of serpentine.
2 is a change in absorption amount of the improved magnesium board according to the amount of acrylic emulsion added.
Table 1 shows the physical and chemical properties of serpentine.
<Table 2> lists the centrifugal vibration mill and Raymond mill equipment used.
Table 3 shows the particle size distribution after ball mill grinding (after 1 hour).
Table 4 shows the particle size distribution of activated serpentine fine powder.
<Table 5> is the main component mixing ratio according to the MgO replacement rate (%).
Table 6 shows the main component mixing ratios for wood flour and perlite fillers.
<Table 7> shows the relative ratios of all the flours replaced with pearlite.
Table 8 shows the chemical compositions and components in the manufacture of the boards used in Examples 3-8.
Table 9 shows the results of surface absorption and absorption rates of magnesium boards in which magnesium oxide prepared in Examples 3 to 8 was replaced with serpentine.
Table 10 shows the gas hazard test of magnesium board.
Table 11 summarizes the physical properties of Examples 3, 4, 5, 6, 7, and 8.

It will be described through the following examples. The examples do not limit the scope of the invention.

1000 kg of serpentine powder was dried at 200-250 ° C. for 6 hours as it was obtained in the developing state. Residual moisture was 0.7%.

<Table 1> shows the physicochemical composition of general serpentine.

                                                        (Unit: wt%) Chemical
Furtherance
Calcium oxide
(CaO) Silicon oxide
(SiO ₂₎ Oxidation
magnesium
(MgO) Train
(T.Fe) Oxidation
aluminum
(Al ₂ O ₃₎ 1.8 ~
2.2 35-42 35 to 40 2.0-3.1 2.1 to 3.0

In Example 1, the dried sample was ground in a general ball mill, and then activated grinding was performed again in a raymond mill and a centrifugal vibration mill. Raymond mill and centrifugal vibration mill are shown in <Table 2>. This Raymond Mill and Centrifugal Vibratory Mill is a grinding and sorting facility equipped with blow-type cyclone and bag filter with maximum throughput of 1 ton per hour. The active, dried product is transferred to a blow pump or fan. Table 3 shows the particle size distribution after ball milling, and Table 4 shows the particle size distribution of the activated fine slag.

Centrifugal vibration mill Raymond Mill Dry Powder Productivity (kg) 300-850 350-2500 Power consumption (kW) 18 37 Raw Material Humidity (%) 5 5 Initial maximum particle size (mm) 5 10 Final particle size (㎛) 10 to 60 7-45

mesh deflation(%) One 2 <5 24.10 26.32 5 ~ 8 28.51 25.73 8-14 20.04 18.25 14-35 10.52 8.91 35-48 6.35 7.25 48-65 7.15 5.03 > 65 2.33 8.51

Mesh
(%) 100/150 150/180 180/250 250/300 300/350 350 < Ball Mill / Centrifugal Vibratory Mill 9.3 13.4 13.9 20.1 26.1 70.5 Ball Mill / Raymond Mill 5.2 13.2 15.3 17.8 22.5 68.2

<Table 8> shows the chemical composition of each board manufacturing raw material used in Examples 3, 4, 5, 6, 7, and 8.

As shown in the table, the main component of the magnesium board produced is composed of wood powder and magnesium oxide (MgO). 10, 30, 50, 70, and 90% of the serpentine fine powder prepared according to Example 1 and Example 2 using the fine powder prepared in Examples 1 and 2 as the main component, and MgO as the main component. After using wood powder as a filler, MgCl ₂ solution or a mixed solution for binder (acrylic emulsion) and glass fiber mesh were laminated on a solid containing filler, and then manufactured by using a roller or a press. It was pressed and molded into a plate-shaped body having a thickness and a size of. At this time, vibration was applied to the mold so that the filling material was well dispersed during the compression and molding process. It was cured over 2 times using magnesium chloride solution.

serpentine 5 15 25 35 45 Wood flour 50 50 50 50 50 Magnesium Oxide (MgO) 45 35 25 15 5

<Table 8> shows the chemical composition at the time of board production of Example 4.

In the present embodiment, the magnesium board is composed of wood powder and pearlite as a filler. Therefore, in the present embodiment, the serpentine substituted with MgO is mixed with wood powder and perlite as a filler in a 1: 1 ratio, and a magnesium chloride solution and an acrylic emulsion 5% solution are used as binders, glass fiber meshes are laminated, and then a roller or It was manufactured by using a press, and pressed and molded into a plate-shaped body having a predetermined thickness and size according to the purpose of use. At this time, vibration was applied to the mold so that the filling material was well dispersed during the compression and molding process. After curing using the magnesium chloride solution in the curing room 2 times.

serpentine 5 15 25 35 45 Wood flour 25 25 25 25 25 Pearlite 25 25 25 25 25 Magnesium Oxide (MgO) 45 35 25 15 5

<Table 8> shows the chemical composition of the board manufacturing used in Example 5.

In this embodiment, 10%, 30%, 50%, 70%, and 90% of magnesium oxide is replaced with pearlite and serpentine as a filler, and a magnesium chloride, a binder solution (acrylic emulsion) and a glass fiber mesh are laminated with a hardening agent. Next, it was manufactured using a roller or a press press, and was pressed and molded into a plate-shaped body having a predetermined thickness and size according to the intended use. At this time, vibration was applied to the mold so that the filling material was well dispersed during the compression and molding process. It was cured over 2 times when using magnesium chloride as a solidifying agent.

serpentine 5 15 25 35 45 Pearlite 50 50 50 50 50 Magnesium Oxide (MgO) 45 35 25 15 5

Table 8 shows the chemical compositions of the boards used in Example 6.

In this embodiment, as in Example 3, instead of MgO, 10%, 30%, 50%, 70%, and 90% of serpentine was substituted, and a binder solution (melamine-based emulsion) was added to solids containing a mixture of wood powder and pearlite as a filler. ) And glass fiber mesh were laminated and manufactured using a roller or a press press, and then compressed and molded into a plate-shaped body having a predetermined thickness and size according to the intended use. At this time, vibration was applied to the mold so that the filling material was well dispersed during the compression and molding process.

<Table 8> shows the chemical composition at the time of board manufacture used in Example 7.

In the present Example was carried out in the same manner as in Example 6, using a phenol resin instead of melamine resin and the rest was carried out under the same conditions.

In Example 8, the magnesium board is composed of magnesium oxide, pearlite, wood flour, and serpentine, as shown in <Table 8>. Therefore, in the present Example was tested in the same manner as in Example 4, but the addition of ultra-fine aluminum hydroxide as a filler and the serpentine replacement rate of MgO was 10, 30, 50, 70, 90% to improve the strength expression . Acrylic resin emulsion and glass fiber mesh were laminated on solid powders including wood powder and pearlite as fillers, and then manufactured by using a roller or a press. The result was compression and molding into a plate having a predetermined thickness and size according to the intended use. At this time, vibration was applied to the mold so that the filling material was well dispersed during the compression and molding process.

ingredient(%) Example 3 Example 4 Oxidation
magnesium
(MgO) 45
(36) 35
(28) 25
(20) 15
(12) 5
(4) 45
(36) 35
(28) 25
(20) 15
(12) 5
(4) serpentine 5
(1.75) 15
(5.25) 25
(8.75) 35
(12.25) 45
(15.75) 5
(1.75) 15
(5.25) 25
(8.75) 35
(12.25) 45
(15.75) Chloride
magnesium
(MgCl ₂ ) 13.48 11.88 10.26 8.66 7.05 13.48 11.88 10.26 8.66 7.05 Wood flour 50 50 50 50 50 25 25 25 25 25 Pearlite - - - - - 25 25 25 25 25 Hydroxide
aluminum
(Al (OH) ₃ ) - - - - - - - - - - Suzy 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 ingredient(%) Example 5 Example 6 Oxidation
magnesium
(MgO) 45
(36) 35
(28) 25
(20) 15
(12) 5
(4) 45
(36) 35
(28) 25
(20) 15
(12) 5
(4) serpentine 5
(1.75) 15
(5.25) 25
(8.75) 35
(12.25) 45
(15.75) 5
(1.75) 15
(5.25) 25
(8.75) 35
(12.25) 45
(15.75) Chloride
magnesium
(MgCl ₂ ) 13.48 11.88 10.26 8.66 7.05 - - - - - Wood flour - - - - - 25 25 25 25 25 Pearlite 50 50 50 50 50 25 25 25 25 25 Hydroxide
aluminum
(Al (OH) ₃ ) - - - - - - - - - - Suzy 2.5 2.5 2.5 2.5 2.5 5 5 5 5 5 ingredient(%) Example 7 Example 8 MgO 45
(36) 35
(28) 25
(20) 15
(12) 5
(4) 45
(36) 35
(28) 25
(20) 15
(12) 5
(4) serpentine 5
(1.75) 15
(5.25) 25
(8.75) 35
(12.25) 45
(15.75) 5
(1.75) 15
(5.25) 25
(8.75) 35
(12.25) 45
(15.75) MgCl ₂ - - - - - 13.48 11.88 10.26 8.66 7.05 Wood flour 25 25 25 25 25 25 25 25 25 25 Pearlite 25 25 25 25 25 25 25 25 25 25 Al (OH) ₃ - - - - - 3 3 3 3 3 Suzy 5 5 5 5 5 5 5 5 5 5

MgO = purity 80%, MgO content in serpentine = 35%

* 2. MgO: MgCl ₂ = 2.8: 1, * 3. MgCl ₂ , resin and Al (OH) ₃ are separately calculated as additives

* 4. MgCl ₂ purity = 46%, * 5, the actual content in ()

Scanning electron microscopy was performed to observe the microstructure of the prepared panel surface after the implementation of Examples 3 to 8. The colorimetric test was carried out over Examples 9-14 to confirm the basic properties of the manufactured magnesium board. , Water absorption, peeling strength, bending failure load test. In addition, a simple fire resistance test and a gaseous toxicity test were conducted using a rat for the purpose of determining whether the fire resistance was improved.

For the colorimetric test, X-rite SP62 model was used to compare the relative whiteness of the existing magnesium board and the developed product.

Conventional magnesium board has a light yellow color on the surface of products produced by wood flour. The color of these surfaces causes problems such as concealment of board surface color and surface color difference after coating during light color coating. Therefore, by replacing a certain amount of wood powder in the conventional magnesium board content with pearlite, the long-term yellowing phenomenon and the surface color appearing during manufacture were improved. Brightness was also measured brighter. As a result of measuring the chromaticity of the board after leaving the magnesium board of Example 3 and the product of Example 4 in natural light for 500 hours, it was found that the brightness was brighter and the yellowing phenomenon was much lower than that of Example 3 product. Can be. Inorganic lightweight fine particles used herein are those having a size of 0.1 mm to 1 mm or less, and the amount of the inorganic lightweight fine particles used is adjusted to about 50% of the amount of wood depending on the purpose.

The general magnesium board has a wood powder content of about 50%, and yellowing phenomenon occurs under long-term wet conditions due to the influence of wood powder, and it is relatively heavy compared to other ingredients and occupies a large proportion of weight per volume. In addition, the wood powder having a large particle makes a large pinhole on the surface of the board, causing appearance problems due to such pinhole after appearance and exterior coating.

In order to improve strength and water resistance, an acrylic emulsion may be added in the manufacturing process to improve the two effects. It is common that acrylic emulsions exhibit an improvement in bending strength when they are added in the manufacturing process of fiber-reinforced cement panels, and acrylic emulsions used in developing magnesium boards are emulsions having excellent water resistance as a laurate series.

Absorption rate (KS F 3504) is to keep the specimen horizontal after drying, place a glass tube or metal tube of about 60mm on the top surface, and to prevent the water leaks by using a sealing material in the outer peripheral portion of the contact with the specimen. After filling with water to 50mm in height and leaving for 3 hours, the surface was wiped with moisture and weighed.

<Figure 2> is a graph showing the absorption amount according to the amount of the emulsion added to the weight of the test period. As shown in FIG. 2, it can be seen that when the 5% by weight of the emulsion is added, the absorption is drastically reduced, and when the 5% and 8% are added, there is no significant difference in the absorption rate. Therefore, it can be seen that the addition of more than 5% of the acrylic emulsion has no significant meaning in improving the waterproofing performance. The table shows the absorption and the absorption rate of the improved product by adding 5% of the acrylic emulsion. In the case of absorption amount, it was found that Example 66 improved magnesium board was about 66.67% less than wood magnesium board. In addition, in the case of the surface absorption rate, it can be observed that the value of the example magnesium board is significantly lower. This phenomenon is thought to be due to the combined effect of the surface film formation of the acrylic emulsion added as a binder and the fine particles of aluminum hydroxide having excellent waterproofing ability. Aluminum hydroxide is not only waterproof but also fine powder of several micrometers. Therefore, it is considered to have waterproof effect by maximizing void filling effect when crimping for board manufacturing.

Test Items Test Methods Test result Example 3 Example 4 Surface absorption
(g) KSF3504 1.3 1.7 0.9 1.8 1.6 1.3 1.4 1.8 1.5 1.5 Surface absorption
(%) Self experiment 0.82 0.76 0.94 0.82 0.87 0.76 0.72 0.79 0.77 0.65 Test Items Test Methods Test result Example 5 Example 6 Surface absorption
(g) KSF3504 1.0 1.2 1.4 1.5 1.4 1.3 1.4 1.5 1.4 1.2 Surface absorption
(%) Self experiment 0.67 0.66 0.69 0.61 0.62 0.61 0.65 0.67 0.69 0.70 Test Items Test Methods Test result Example 7 Example 8 Surface absorption
(g) KSF3504 1.5 1.2 1.1 1.3 1.5 1.2 1.3 1.1 1.2 1.3 Surface absorption
(%) Self experiment 0.54 0.61 0.65 0.60 0.71 0.70 0.61 0.65 0.64 0.64

Surface peeling strength (KS F 3200) of Examples 3 to 8 was measured. The specimen is attached to a steel or aluminum block and the tensile load is applied perpendicular to the surface of the specimen to determine the maximum load at peeling failure.

MgO-replacement serpentine magnesium boards exhibited the highest bond strength values. In the case of wood flour replacement boards, the bond strength drops from the highest level and then increases again. This may be due to the second generation of strength after the initial dropout due to the fiber mesh present inside the board. In the case of gypsum board, it is easy to observe the dropout phenomenon even with relatively low strength and low deformation.

Flexural failure load test (KS F 3504) was performed for each example. The test was carried out by setting the span ratio to 350 mm and applying the concentrated load to all the butterflies at the center of the span.

Table 7 shows the property test results of the magnesium board according to the present invention and the board supplied in Korea. It shows the bending fracture load for each board type. As observed, the developed magnesium board exhibited a relatively high bending fracture load of about 57 kg, while the board of Example 8 exhibited the highest bending fracture load, but the deformation amount of the board exhibited the lowest value. It is relatively strong in strength but brittle, so it can be said that the board can be destroyed even with a slight impact. In the case of the replacement wood magnesium board, the deformation amount was relatively good until fracture. Example 3 In the case of the board, the bending strength is weak but it can be seen that the strain is very excellent.

The gypsum board was observed to be largely deformed due to the load because it was not completely separated from the base paper for the board attached to both sides and the gypsum surface.

The screw holding force test (KS F 3200) of Examples 3 to 8 was conducted. A screw of diameter 2.7mm and a length of 16mm is inserted perpendicularly to the test specimen, and 11mm of the screw is inserted vertically. The test piece is fixed, and the screw is pulled vertically and measured.

The board of Example 8 exhibited the highest value. This may be due to the combined effect of wood flour, pearlite, and MgCl _{2 as} the main components. In the case of screw holding force, it shows how well the board is attached to the construction surface after construction, and MgO magnesium board was found to have superior performance compared to general gypsum board.

As described above, MgO magnesium boards were observed to have superior physical performance compared to gypsum boards, which is a standard comparison target.

Nonflammability experiments were carried out for Examples 3-8. The results of a simple fire resistance test showing the surface temperature change while heating a 3mm, 6mm, and 9mm magnesium board using an oxygen torch for 30 minutes. It can be seen that the temperature of the front surface of the board and the rear surface of each board is observed to be highest in a short time according to the heating time.The temperature deviation of the front and rear panels is similar to the board type and thickness. appear. In general gypsum board, the temperature of the rear part was about 300 ℃, and 3mm magnesium board was observed higher than this. However, 6mm and 9mm MgO substitute magnesium board showed lower insulation temperature than gypsum board, which showed excellent insulation performance. In the case of gypsum board, after about 9 minutes of heating time, cracks occurred in the board, which made the experiment impossible. The 6mm and 9mm magnesium boards showed almost constant thermal insulation properties for 30 minutes, and no crack was observed. Therefore, it is considered that the magnesium board having 6mm or more heat insulation and fire resistance is better than gypsum board.

<Table 7> compares maximum temperature deviation of front and back of board. As observed in the figure, it was found that the 3mm magnesium board had the lowest temperature deviation, and the temperature deviation of the 6mm and 9mm improved magnesium boards was higher than that of the gypsum board. Based on the above two results, it can be observed that the 6mm and 9mm magnesium boards are much better in heat resistance and insulation performance than 9mm gypsum boards.

Existing magnesium board generates flame and toxic gas in case of fire. This is caused by the wood powder contained in the magnesium board, the higher the amount of wood powder, the occurrence frequency and the amount of toxic gas tends to increase. This tendency is sufficient to pass the criteria in the nonflammability test of KS F 2271, but it needs to be developed according to the better quality requirements of the product.

Serpentine: Magnesium oxide (1: 1) (9 mm each) The behavior stop time of 8 rats when burning magnesium board is shown in <Table 9>. In the case of the existing board, it can be seen that the behavioral stop time of the experimental rats is variously distributed from about 600 to 880 seconds, and the average time of the suspension time is 747 seconds. In the case of the improved magnesium board, it was observed that the behavioral stop time of the mice was distributed almost uniformly from about 850 to 900 seconds, and the average was 885 seconds.

Therefore, it was found that the gaseous harmfulness was greatly improved as compared with the conventional magnesium board. As mentioned above, it was possible to reduce the amount of flame and toxic gas generated by using the inorganic perlite of Example 4 and the aluminum hydroxide fine particles of Example 8 in place of the wood powder of Example 3.

The aluminum hydroxide-based fine particles are selected from the group consisting of silicon oxide (SiO ₂ ) 62.0 ~ 68.0 wt%, aluminum oxide (Al ₂ O ₃ ) 18.0 ~ 23.0 wt%, sodium oxide (Na ₂ O) 0.05 ~ 8.0 wt% Was used, the particle size was used was 0.01 ~ 0.05mm. When the aluminum hydroxide-based fine particles are used, it was found that the gas-hazardous performance of the product was improved as shown in Table 9.

Test Items Result (seconds) Domestic standard Existing board Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 KS F 2271 Gas hazard test
(Measurement of stop time of laboratory rats) 8 downtimes
(Average) 747 892 850 829 880 852 833 540 seconds or more Standard Deviation 105 32 18 29 34 29 38

MgO
% Substitution Bending Breaking Weight (kg) / Displacement (mm) Bond strength
(kg / mm) Screw holding force
(kg / mm) Refractoriness (Maximum Temperature (Front / Rear)) ℃ Example 3 10 21 / 5.7 33.0 / 1.1 25.2 / 0.5 1211/280 30 20.2 / 8.5 33.0 / 1.1 25.1 / 0.4 1208/330 50 19.3 / 8.4 32.8 / 1.0 24.7 / 0.4 1130/341 70 19.0 / 8.3 32.5 / 0.9 23.8 / 0.3 1139/355 90 14.6 / 7.4 28.8 / 0.6 20.1 / 0.1 1148/362 Example 4 10 66 / 2.1 55.6 / 0.50 66.3 / 1.0 1120/276 30 64.5 / 2.0 55.5 / 0.50 66.2 / 0.9 1141/287 50 63.2 / 1.9 49.8 / 0.48 65.2 / 0.8 1140/299 70 62.3 / 1.8 49.2 / 0.47 65.1 / 0.8 1132/293 90 51.1 / 1.5 40.6 / 0.41 58.2 / 0.5 1150/315 Example 5 10 36.7 / 3.5 77.9 / 0.52 29.5 / 0.8 1210/250 30 35.5 / 3.4 76.3 / 0.51 28.2 / 0.8 1190/257 50 32.6 / 3.3 76.2 / 0.50 28.5 / 0.7 1201/269 70 31.7 / 3.2 75.1 / 0.46 26.7 / 0.7 1208/279 90 28.8 / 2.6 69.0 / 0.38 24.4 / 0.25 1194/290 Example 6 10 34.8 / 3.9 57.3 / 0.45 65.2 / 0.7 1162/296 30 34.7 / 3.9 55.1 / 0.43 63.7 / 0.3 1161/307 50 34.2 / 3.8 54.5 / 0.43 64.8 / 0.6 1163/314 70 33.1 / 3.7 53.6 / 0.41 63.0 / 0.6 1160/317 90 28.6 / 3.0 43.2 / 0.32 57.4 / 0.4 1142/321 Example 7 10 33.2 / 4.1 54.9 / 0.47 65.0 / 1.0 1180/292 30 32.9 / 4.0 54.0 / 0.46 63.4 / 0.9 1207/296 50 31.7 / 3.6 52.9 / 0.43 62.6 / 0.9 1208/299 70 31.8 / 3.6 51.0 / 0.41 62.1 / 0.8 1213/309 90 26.7 / 2.9 45.0 / 0.23 52.2 / 0.6 1202/323 Example 8 10 70.8 / 0.7 76.7 / 0.37 71.2 / 1.3 1206/252 30 70.2 / 0.6 74.4 / 0.36 70.3 / 1.2 1197/262 50 69.0 / 0.6 74.0 / 0.36 69.2 / 1.2 1186/271 70 67.1 / 0.5 67.7 / 0.33 69.1 / 1.1 1205/282 90 53.8 / 0.3 51.8 / 0.29 60.2 / 0.9 1206/290

none.

Claims (6)

Magnesium oxide board is manufactured from serpentine as a raw material, the first process of drying serpentine, the second process of crushing and activating, the third process of preparing and activating powder, and the fine powder Non-flammable magnesium oxide board production using serpentine by the mechanochemical method consisting of the fourth step of mixing, forming and curing magnesium board by mixing, forming and curing using all or part of phosphorus magnesium chloride. The method according to claim 1, wherein the serpentine has a chemical composition of 35 to 42% by weight of silicon dioxide (SiO ₂ ), 35 to 40% of magnesium oxide (MgO), 2 to 3% of iron powder (T.Fe) and aluminum oxide ( Al ₂ O ₃ ) Nonflammable magnesium oxide board production using serpentine by mechanochemical method characterized in that 2.1% ~ 3.0, calcium oxide (CaO) 1.8 ~ 2.2%. delete The method of claim 1, wherein the particle size of the activated crushed slag pulverized in the second process to pulverized to less than 100 mesh, the production of non-combustible magnesium oxide board using a serpentine by a mechanical chemical method. delete delete

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