A magnesia cement fireproof board and its preparation method

Abstract

The present invention relates to the technical field of fireproof materials, and provides a magnesia cement fireproof board and a preparation method thereof. The method includes mixing a first raw material containing magnesium chloride, a first filler and sodium hydroxide to obtain a first mixture; the filler includes wood powder; adding water to the first mixture in batches and stirring to mix, to obtain a second mixture; adding a second raw material containing light-burned magnesia to the second mixture and mixing for less than 30 minutes to obtain a third mixture; adding a third raw material containing a second filler to the third mixture and mixing to obtain a fourth mixture; placing the fourth mixture in a mold and curing to obtain the magnesia cement fireproof board. In the present invention, wood powder is added to the magnesia cementitious material, realizing the recycling of resources. Moreover, when adding wood powder, sodium hydroxide is introduced at the same time, and the stepwise feeding method is optimized, realizing the stable improvement of mechanical properties while greatly shortening the curing time. It also has the properties of fireproofing, water resistance and excellent environmental protection, and has great application potential.

Description

Technical Field

[0001] The present invention relates to the technical field of fireproof materials, and particularly relates to a magnesia cement fireproof board and a preparation method thereof. Background Art

[0002] With the continuous improvement of people's requirements for the safety of living environment and the quality of life, as well as the increasingly strict requirements for the performance of materials in industries such as construction and furniture, as the main material for interior decoration and furniture manufacturing, the quality and safety of artificial boards have received extensive attention. Traditional artificial boards, such as plywood and particleboard, often require the use of a large amount of adhesives in the production process. These adhesives mostly contain harmful substances such as formaldehyde, and the long-term release will pose a potential threat to human health. At the same time, the vast majority of artificial boards use wood materials as the base material, and are prone to defects such as deformation, swelling, cracking, and edge banding falling off in a humid environment, seriously affecting their use effect. In addition, new requirements for fireproof performance are also put forward for the boards used in public places such as hospitals, schools, and libraries.

[0003] In summary, developing an artificial board that not only has excellent fireproof and water-resistant properties but also can achieve formaldehyde-free environmental protection not only meets the current market demand for high-performance and environmentally friendly materials but also is an important direction to promote the transformation and upgrading of the artificial board industry and achieve sustainable development.

[0004] In this context, artificial board products that can simultaneously solve the problems of fireproof, water-resistant, and environmental protection and have low costs have become a research hotspot. To simultaneously improve the fireproof and water-resistant properties of the board, a composite flame retardant and waterproof agent can be added to the board, which usually contains inorganic flame retardant components and waterproof components. These components can release inert gases at high temperatures to block combustion, and at the same time form a waterproof layer on the surface or inside of the board to prevent water penetration, but this easily increases the production cost of the board. To further reduce formaldehyde or even achieve formaldehyde-free, using natural plant adhesives (such as soybean protein glue, starch glue, etc.) to replace traditional formaldehyde adhesives is the main research direction. Although natural adhesives perform excellently in environmental protection, their bonding strength and water resistance are insufficient, resulting in the board being prone to cracking, deformation, or water absorption and swelling during use. And magnesia cementitious materials, as an inorganic adhesive, can also achieve the effects of waterproof, fireproof, and formaldehyde-free, but the time required to reach the initial setting strength and the final strength is relatively long, and it is easy to agglomerate after doping with wood fibers, resulting in unstable mechanical properties, thus limiting the application of magnesia cementitious materials in fireproof boards. Summary of the Invention

[0005] The present invention provides a magnesia cement fireproof board and a preparation method thereof. Through the self-developed formula and process of the board, the average flexural strength of the board reaches more than 5.3 MPa, and the average elastic modulus reaches more than 5000 MPa, meeting the performance requirements of building and decoration materials. At the same time, it has the properties of fire prevention, water resistance and environmental protection. In addition, industrial wastes such as fly ash are used in the formula, greatly shortening the processing time, reducing the cost and realizing the recycling of resources.

[0006] In the first aspect, the present invention provides a preparation method of a magnesia cement fireproof board, including:

[0007] Mixing a first raw material containing magnesium chloride, a first filler and sodium hydroxide to obtain a first mixture; the first filler includes wood powder;

[0008] Adding water in batches to the first mixture and stirring to mix, obtaining a second mixture;

[0009] Adding a second raw material containing light-burned magnesia to the second mixture and mixing for less than 30 minutes to obtain a third mixture;

[0010] Adding a third raw material containing a second filler to the third mixture and mixing to obtain a fourth mixture;

[0011] Placing the fourth mixture in a mold and curing to obtain the magnesia cement fireproof board.

[0012] As mentioned above, magnesia cementitious materials have certain advantages in the directions of fire prevention, water resistance and environmental protection. However, when used in the preparation of fireproof boards, the use of wood powder will cause problems of unstable mechanical properties of the fireproof board. In order to promote the dispersion of wood powder in the system and avoid the unstable mechanical properties caused by agglomeration, the present invention first optimizes the ratio of magnesium chloride and magnesia. It is found that although optimizing the ratio of the two is beneficial to improving mechanical properties, such as average flexural strength and average elastic modulus, the initial setting time is relatively long, and the time required to reach the initial setting strength and the final strength is relatively long.

[0013] Based on this, through in-depth research, the present invention introduces sodium hydroxide simultaneously when adding wood powder. On the one hand, the extractives and lignin in the wood powder are partially dissolved by the action of sodium hydroxide, increasing the porosity inside the wood, so as to form a better interpenetrating network structure between the subsequent wood powder and the magnesia cementitious material, improving the mechanical properties of the board. On the other hand, the first raw materials containing magnesium chloride, the first filler containing wood powder, and sodium hydroxide are premixed and then water is added. The premixing achieves more uniformity, and at the same time, by using the heat released during the reaction of magnesium chloride and sodium hydroxide with water during the water addition process, it further accelerates and strengthens the dissolution of the extractives and lignin in the wood powder by sodium hydroxide, achieving a stable improvement in mechanical properties, avoiding too long processing time, and not requiring separate treatment of the wood, thus saving costs. Further, the present invention also separately adds light-burned magnesia and the third raw material containing the second filler, and controls the mixing time of the light-burned magnesia within 30 minutes because: the initial setting time after mixing magnesium chloride, magnesium oxide, and water is generally within 120 minutes. Completing the mixing within 30 minutes can keep the mixture in a thick emulsion or cream-like state, so that the third raw material can be mixed evenly subsequently. If it is not completed within 30 minutes, it will lead to a decline in the mechanical properties of the obtained fireproof board and instability.

[0014] In addition, the wood powder in the present invention is also used to increase the strength-to-weight ratio of the magnesia cementitious fireproof board, but the amount of wood powder added cannot be too much, otherwise it will affect the mechanical properties and flame retardant properties. The mass ratio of the magnesium chloride to the wood powder is 10:20 - 40, preferably 10:30; the mass ratio of the wood powder to the sodium hydroxide is 30:3 - 7, preferably 30:5.

[0015] According to the preparation method of the magnesia cementitious fireproof board provided by the present invention as described above, the curing includes tamping in a mold, taking out the green blank after curing for 1 - 2 days, and the green blank is further cured for more than 7 days. During the further curing period, the surface of the green blank is sprayed with water to keep the surface moist.

[0016] The reason for keeping the surface moist in the present invention is that the hydration process is a continuous process and is accompanied by slow heat release. When the water evaporates, it will damage the whiskers of the formed 518 crystals, and this structure of the 518-phase whiskers is the key to forming the interpenetrating network structure. Therefore, keeping the surface moist will slow down the water evaporation rate and at the same time make the internal moisture of the material sufficient, which is beneficial to the progress of the hydration reaction, thereby improving the mechanical properties of the magnesia cementitious fireproof board.

[0017] The above tamping is to reduce internal bubbles.

[0018] In the present invention, the main functions of fly ash are to increase the number of micropores in the material, reduce the thickness of the hydration layer, and form a more dense interpenetrating network structure, thereby increasing the elasticity of the magnesia cement fireproof board. However, the addition amount of fly ash should not be too large, otherwise it will hinder the hydration reaction process and have a negative impact on the comprehensive performance of the magnesia cement fireproof board. According to the preparation method of the magnesia cement fireproof board as described above provided by the present invention, the first filler further includes fly ash; the mass ratio of magnesium chloride to fly ash is 10:5 to 15; preferably 10:10.

[0019] The hydration reaction mechanism of the fireproof board of the present invention mainly involves the chemical reactions between magnesium oxide, water, magnesium chloride and other components. It mainly includes that magnesium oxide will undergo a hydration reaction in the presence of water to generate magnesium hydroxide, and the hydrogen ions generated by the hydrolysis of magnesium chloride can neutralize the alkalinity of magnesium hydroxide, thereby promoting the further hydration of magnesium oxide, and a double salt with cementing properties is generated. In order to make the mechanical properties and fireproof properties of the fireproof board better, the present invention regulates the mass ratio of magnesium chloride to light-burned magnesium oxide. According to the preparation method of the magnesia cement fireproof board as described above provided by the present invention, the mass ratio of magnesium chloride to light-burned magnesium oxide is 10:10 to 25, preferably 10:20.

[0020] Silane coupling agent is a special organosilicon compound, which can act as a "molecular bridge" to improve the interfacial action between the second filler (such as kaolin, iron oxide, etc.) and the organic matter. The present invention regulates the mass ratio of magnesium chloride to silane coupling agent, which can significantly improve the mechanical properties of the fireproof board and increase the flexural strength and elastic modulus. According to the preparation method of the magnesia cement fireproof board as described above provided by the present invention, the third raw material further includes a silane coupling agent; the mass ratio of magnesium chloride to silane coupling agent is 10:1 to 2, preferably 10:1.

[0021] In order to reasonably control the initial setting time, it is preferred that the silane coupling agent is KH560.

[0022] Correspondingly, after adding the silane coupling agent, the initial setting time of the magnesia cementitious material will be shortened to about 15 minutes. Therefore, it must be quickly and evenly mixed before reaching the initial setting. That is: the third raw material is added to the third mixture in batches and mixed for less than 15 minutes to obtain a fourth mixture; if the third raw material is not added within 15 minutes, it will cause the mechanical properties of the obtained fireproof board to decline and be unstable.

[0023] Generally, kaolin is a natural clay mineral with a relatively high melting point and can form a stable ceramic phase at high temperatures. In a fireproof board, kaolin can form a hard ceramic layer at high temperatures, playing a role in heat insulation and flame retardancy. It has been found that in the invention, kaolin can further enhance the interfacial bonding between various materials. According to the preparation method of the magnesia cement fireproof board as described above provided by the present invention, the second filler includes kaolin; the mass ratio of magnesium chloride to kaolin is 10:10 - 20, preferably 10:10.

[0024] Generally, iron oxide has relatively high thermal stability and can improve the heat resistance of materials in a fireproof board. It can form a stable oxide layer at high temperatures to prevent further oxidation and decomposition of the materials. It has been found that in the invention, iron oxide can also promote the hydration reaction and reduce the curing time to reach the final strength. According to the preparation method of the magnesia cement fireproof board as described above provided by the present invention, the second filler further includes iron oxide; the mass ratio of magnesium chloride to iron oxide is greater than or equal to 10:3.

[0025] Since the third raw material also includes substances such as kaolin and iron oxide, which will further shorten the initial setting time, therefore, the third raw material is added in batches to the third mixture, and the mixing time is preferably controlled within 10 min to obtain a fourth mixture.

[0026] According to the preparation method of the magnesia cement fireproof board as described above provided by the present invention, the first raw material is mixed in a horizontal mixer with a dispersing rod to obtain a first mixture.

[0027] According to the preparation method of the magnesia cement fireproof board as described above provided by the present invention, adding water in batches to the first mixture and stirring and mixing are carried out in a planetary mixer, the stirring speed is less than or equal to 20 r / min, the stirring and mixing time is more than 30 min, and the addition speed of the water is controlled so that the system temperature is 85 - 95 °C to obtain a second mixture.

[0028] The horizontal mixer with a dispersing rod of the present invention is used to mix the first raw material, which can effectively avoid the agglomeration of wood powder and fly ash.

[0029] According to the preparation method of the magnesia cement fireproof board as described above provided by the present invention, by weight, its raw materials include: 10 parts of magnesium chloride, 20 - 40 parts of wood powder, 5 - 15 parts of fly ash, 5 - 7 parts of sodium hydroxide, 35 - 45 parts of water, 15 - 25 parts of light burned magnesia, 1 - 1.5 parts of silane coupling agent, 10 - 11 parts of kaolin, and 3 - 4 parts of iron oxide.

[0030] In a second aspect, the present invention also provides a magnesia cement fireproof board prepared by the preparation method of the magnesia cement fireproof board as described above.

[0031] The present invention provides a magnesium cementitious fireproof board and a preparation method thereof, wherein wood powder is added to the magnesium cementitious material to realize the recycling of resources, and sodium hydroxide is introduced simultaneously when the wood powder is added, and the step-by-step feeding method is optimized, thereby realizing stable improvement of mechanical properties while greatly shortening the curing time, and having fireproof, water-resistant and excellent environmental protection properties, and having great application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a structural schematic diagram of the mixer provided by the present invention.

[0034] Description of the drawings: 1: mixture, 2: mixing chamber, 3: beating rod. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Combine the following Figure 1 The invention describes a magnesium gelled fireproof board and a preparation method thereof.

[0037] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0038] Example 1

[0039] A method for preparing a magnesium gelled fireproof board, the steps of which are as follows by weight:

[0040] (1) 10 parts of magnesium chloride, 30 parts of wood flour, 5 parts of sodium hydroxide and 10 parts of fly ash are mixed uniformly in a horizontal mixer equipped with a beating bar to obtain a first mixture.

[0041] Among them, Figure 1As shown in the figure, the horizontal mixer with a dispersing rod includes a mixing bin 2 and a dispersing rod 3 located inside the mixing bin 2. In the present invention, the mixture 1 is added into the mixing bin 2, and the mixing bin 2 is rotated so that the mixture 1 therein is stirred evenly under the action of the dispersing rod 3.

[0042] (2) Add 40 parts of water in batches to the first mixture prepared in step (1), and stir evenly in a planetary mixer to obtain a second mixture; wherein, control the stirring speed to be 20 r / min, control the temperature of the system to be about 90 °C during the process of adding water in batches, and the mixing time is 35 min.

[0043] (3) Gradually add 20 parts of light-burned magnesia to the second mixture in step (2), mix evenly, and the mixing time is 30 min to obtain a third mixture.

[0044] (4) Mix 1 part of KH560 silane coupling agent, 10 parts of kaolin and 3 parts of iron oxide (III) evenly and add them to the third mixture in step (3) in batches. This process is completed in 10 min to obtain a fourth mixture in the form of a thick cream paste.

[0045] (5) Place the fourth mixture in step (4) on a mold, vibrate it solid, and cure it for 1 day.

[0046] (6) Take out the green body from the mold, and continue to cure the green body for 7 days. During the curing period, the surface needs to be sprayed with water to keep the surface moist.

[0047] (7) Sand and trim the edges to obtain a magnesia cement fireproof board.

[0048] Example 2

[0049] A method for preparing a magnesia cement fireproof board is basically the same as that in Example 1, except that in step (6), it is specifically as follows:

[0050] (6) Take out the green body from the mold, and the green body continues to cure in normal-temperature air for 7 days, that is, it is not moisturized during the curing period.

[0051] Comparative Example 1

[0052] A method for preparing a magnesia cement fireproof board is basically the same as that in Example 1, except that in the preparation process of the second mixture, it is specifically as follows:

[0053] Mix 10 parts of magnesium chloride, 30 parts of wood powder, 5 parts of sodium hydroxide, 10 parts of fly ash and 40 parts of water evenly in a planetary mixer to obtain a second mixture; wherein, control the stirring speed to be 20 r / min, control the temperature of the system to be 90 °C, and the mixing time is 35 min.

[0054] The magnesia-based gelled fireproof boards obtained in Comparative Example 1 and Examples 1 to 2 were tested, and the results are shown in Tables 1 to 2 below. Among them, the test methods for the flexural strength and elastic modulus refer to GB / T 17657-2022.

[0055] Table 1

[0056]

[0057] Table 2

[0058]

[0059] As can be seen from the results shown in Tables 1 to 2, the tests were carried out with different mixing methods and curing methods. The mechanical properties after mixing together were poor and the variance was large, indicating uneven mixing. After spraying water for moisture preservation and curing, the mechanical properties were improved, and the flexural strength was significantly improved.

[0060] Example 3

[0061] A preparation method of a magnesia-based gelled fireproof board is basically the same as that of Example 2, except that in step (6), it is specifically as follows:

[0062] (6) Take out the green blank from the mold, and the green blank is further cured in normal-temperature air for 14 days, that is, without moisture preservation during the curing period.

[0063] Example 4

[0064] A preparation method of a magnesia-based gelled fireproof board is basically the same as that of Example 2, except that in step (6), it is specifically as follows:

[0065] (6) Take out the green blank from the mold, and the green blank is further cured in normal-temperature air for 30 days, that is, without moisture preservation during the curing period.

[0066] Example 5

[0067] A preparation method of a magnesia-based gelled fireproof board is basically the same as that of Example 2, except that ferric oxide is not added.

[0068] Example 6

[0069] A preparation method of a magnesia-based gelled fireproof board is basically the same as that of Example 3, except that ferric oxide is not added.

[0070] Example 7

[0071] A preparation method of a magnesia-based gelled fireproof board is basically the same as that of Example 4, except that ferric oxide is not added.

[0072] The magnesia-based gelled fireproof boards obtained in Examples 2 to 7 were tested, and the results are shown in Table 3 below.

[0073] Table 3

[0074]

[0075] As can be seen from the results shown in Table 3, after adding 3% iron oxide, the average flexural strength and modulus of elasticity at 7 days of curing are close to the indicators of the formulation without adding iron oxide at 14 days of curing. From the comparison of the above different curing days, it can also be seen that iron oxide has a more significant effect on improving the mechanical properties at 7 days of curing. Therefore, the next processing can be carried out after 7 days of curing with the addition of iron oxide.

[0076] Example 8

[0077] A preparation method of a magnesia cement fireproof board is basically the same as that of Example 7, except that: the amount of kaolin is adjusted to 20 parts.

[0078] Example 9

[0079] A preparation method of a magnesia cement fireproof board is basically the same as that of Example 7, except that: no kaolin is added.

[0080] The magnesia cement fireproof boards obtained in Examples 7 to 9 were tested, and the results are shown in Table 4 below.

[0081] Table 4

[0082]

[0083] As can be seen from the results shown in Table 4, kaolin further regulates the mechanical properties of the material.

[0084] Example 10

[0085] A preparation method of a magnesia cement fireproof board is basically the same as that of Example 9, except that: the amount of KH560 silane coupling agent is adjusted to 2 parts.

[0086] Example 11

[0087] A preparation method of a magnesia cement fireproof board is basically the same as that of Example 9, except that: no KH560 silane coupling agent is added.

[0088] The magnesia cement fireproof boards obtained in Examples 9 to 11 were tested, and the results are shown in Table 5 below.

[0089] Table 5

[0090]

[0091] As can be seen from the results shown in Table 5, although adding KH560 will increase the modulus of rupture and elastic modulus, considering the relatively high cost of KH560, the mass ratio of the magnesium chloride to the silane coupling agent is preferably 10:1.

[0092] Example 12

[0093] A method for preparing a magnesia cement fireproof board is basically the same as that of Example 11, except that: 3 parts of sodium hydroxide are added in step (1).

[0094] Example 13

[0095] A method for preparing a magnesia cement fireproof board is basically the same as that of Example 11, except that: 7 parts of sodium hydroxide are added in step (1).

[0096] Comparative Example 2

[0097] A method for preparing a magnesia cement fireproof board is basically the same as that of Example 11, except that: no sodium hydroxide is added.

[0098] The magnesia cement fireproof boards obtained in Examples 11 to 13 and Comparative Example 2 were tested, and the results are shown in Table 6 below.

[0099] Table 6

[0100]

[0101] As can be seen from the results shown in Table 6, although adding sodium hydroxide will increase the modulus of rupture and elastic modulus, considering that the performance improvement from 5 parts to 7 parts is not as good as that from 3 parts to 5 parts, and the cost of sodium hydroxide is relatively high, 5 parts are preferably used.

[0102] Comparative Examples 3 to 10

[0103] A method for preparing a magnesia cement fireproof board is basically the same as that of Comparative Example 2, except that: the number of parts of fly ash and wood powder is as shown in Table 7 below.

[0104] Table 7

[0105]

[0106] The magnesia cement fireproof boards obtained in Comparative Examples 3 to 10 were tested, and the results are shown in Table 8 below.

[0107] Table 8

[0108]

[0109] As can be seen from the results shown in Tables 7 to 8, too much wood powder cannot be added, otherwise it will affect the mechanical properties. The addition amount of fly ash should not be too large, otherwise it will hinder the hydration reaction process and have a negative impact on the mechanical properties of the magnesia cement fireproof board.

[0110] Comparative Example 11

[0111] A preparation method of a magnesia cement fireproof board, calculated by weight, comprises the following steps:

[0112] (1) Mix 10 parts of magnesium chloride and 10 parts of light-burned magnesia to obtain a mixture.

[0113] (2) Add 30 parts of water to the mixture in step (1) in batches, control the temperature of the system at 90 °C, and the mixing time is 85 min to obtain a thick cream-like material.

[0114] (3) Place the thick cream-like material in step (2) on a mold, compact it, and cure for 1 day.

[0115] (4) Take out the green body from the mold, and the green body is further cured in normal temperature air for 30 days, that is, no moisture is maintained during the curing period.

[0116] (5) Sand and trim to obtain a magnesia cement fireproof board.

[0117] Comparative Example 12

[0118] A preparation method of a magnesia cement fireproof board is basically the same as that of Comparative Example 11, the difference is only that: the number of parts of light-burned magnesia is adjusted to 15 parts.

[0119] Comparative Example 13

[0120] A preparation method of a magnesia cement fireproof board is basically the same as that of Comparative Example 11, the difference is only that: the number of parts of light-burned magnesia is adjusted to 20 parts.

[0121] Comparative Example 14

[0122] A preparation method of a magnesia cement fireproof board is basically the same as that of Comparative Example 11, the difference is only that: the number of parts of light-burned magnesia is adjusted to 25 parts.

[0123] The magnesia cement fireproof boards obtained in Comparative Examples 11 to 14 were tested, and the results are shown in Table 9 below.

[0124] Table 9

[0125]

[0126] As can be seen from the results shown in Table 9, optimizing the ratio of magnesium chloride and magnesia is beneficial to improving the mechanical properties, such as the average static bending strength and the average elastic modulus, but the initial setting time is longer.

[0127] The water resistance and flame retardancy of the magnesia cement fireproof board obtained in Example 1 were tested, and the results are shown in Table 10 below.

[0128] Table 10

[0129]

[0130] As can be seen from Table 10 above, its waterproof performance is excellent and it can reach the A2 fireproof grade. The reason for the formaldehyde release is that wood naturally contains some formaldehyde, which belongs to the composition of natural substances.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a magnesium gelled fireproof board, characterized in that: include: A first raw material including magnesium chloride, a first filler and sodium hydroxide is mixed to obtain a first mixture; the first filler includes wood powder and fly ash; the mass ratio of the magnesium chloride to the wood powder is 10:20-40; the mass ratio of the wood powder to the sodium hydroxide is 30:3-7; the mass ratio of the magnesium chloride to the fly ash is 10:5-15; adding water in batches to the first mixture and stirring to obtain a second mixture; adding the second raw material containing light-burned magnesium oxide to the second mixture and mixing for less than 30 minutes to obtain a third mixture; the mass ratio of the magnesium chloride to the light-burned magnesium oxide is 10:10-25; Adding the third raw material containing the second filler and the silane coupling agent into the third mixture in batches and mixing for less than 10 minutes to obtain a fourth mixture; the mass ratio of the magnesium chloride to the silane coupling agent is 10:1-2; the second filler includes kaolin; the mass ratio of the magnesium chloride to the kaolin is 10:10-20; the second filler also includes iron oxide; the mass ratio of the magnesium chloride to the iron oxide is greater than or equal to 10:3; The fourth mixture is placed in a mold and cured to obtain the magnesium gelled fireproof board; the curing includes vibrating in the mold, taking out the preliminary blank after curing for 1 to 2 days, and continuing to cure the preliminary blank for more than 7 days. During the continued curing, the surface of the preliminary blank is sprayed with water to keep the surface moist.

2. The method for preparing the magnesium gelled fireproof board according to claim 1, characterized in that: The first raw materials are mixed in a horizontal mixer with a beating bar to obtain a first mixture.

3. The method for preparing the magnesium gelled fireproof board according to claim 2, characterized in that: The water is added to the first mixture in batches and stirred and mixed in a planetary mixer at a stirring speed of less than or equal to 20 r / min for a stirring and mixing time of more than 30 min. The water addition speed is controlled so that the system temperature is 85-95° C. to obtain a second mixture.

4. A magnesium gelled fireproof board, characterized in that: The magnesium gelled fireproof board is prepared by the preparation method of any one of claims 1 to 3.

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