CN101007725B - A water-resistant magnesium oxychloride-silicon composite material and its preparation method - Google Patents

Abstract

The present invention is a silicon oxide, magnesium oxide, aluminum oxide, magnesium chloride composite material and its preparation method. The composite material uses silica fume or calcined kaolin as the modified material of the magnesium oxychloride cement system. The composite material has a main gelling material, Reinforcing material, toughening material, filling material, interface modifier, water-resistant agent; the preparation method is to prepare the main gelling material in proportion, add filling material, reinforcing material, interface modifier, toughening agent, water-resistant agent; after mixing and stirring, the magnesium oxychloride-silicon composite material mixture is poured into a mold to form at room temperature, demolded and cured. Advantages: Abundant raw materials and good thermal stability. The preparation method is simple, the bending strength at room temperature is 20-30MPa, the compressive strength is 60-80MPa, the material density is 0.9-1.8g/cubic centimeter, and the elastic modulus is 50GPa. It can replace wood and make firewalls, doors, light interior walls, indoor External decoration materials, advertising light boxes, chassis trays, and packing box boards.

Description

A water-resistant magnesium oxychloride-silicon composite material and its preparation method

technical field

The present invention relates to a silica, magnesia, alumina, magnesium chloride composite material and its preparation method. The present invention is an expansion and extension of the magnesium oxychloride cement system. The composite material has hydraulicity through modification technology, To overcome the low softening coefficient of magnesium oxychloride cement, the invention belongs to the technical field of magnesium oxychloride cement series composite materials.

background technology

Magnesium oxychloride cement cement is formed by blending light-burned MgO ₂ , MgCl and H ₂ O according to a certain ratio, and is also called Sorel cement. Magnesium oxychloride cement is an air-hardening cementitious material. A series of excellent properties are mainly manifested in: fast setting and hardening; high mechanical strength; weak alkalinity and low corrosion resistance; wear resistance better than sulphoaluminate cement, alumina cement and Portland cement; It has good adhesion with wood fiber, and can form composite materials with various materials to be used as wood substitute materials; excellent flame retardancy; good heat insulation, the thermal conductivity of magnesium oxychloride cement is 0.14~0.23W/m ·K. However, magnesium oxychloride cement adhesive materials also have obvious disadvantages and application limitations, mainly in: poor water resistance, the strength of general magnesium oxychloride cement products is reduced by 70% to 80‰ after soaking in water for 28 days; It is easy to absorb moisture and return to halogen, and condensation will appear on the surface of the product; improper proportion or too high content of active magnesium oxide in the raw material will cause too fast reaction and concentrated heat release, which not only affects the production operation, but also easily leads to warping and deformation of the product. These ills seriously affect product quality and restrict the development of the industry.

The main hydration phases of magnesium oxychloride cement are (5Mg(OH), MgCl ₂ , 8H ₂ O) referred to as 5 phases and (3Mg(OH) ₂ , MgCl ₂ , 8H ₂ O) referred to as 3 phases, magnesium oxychloride cement in MgO , MgCl ₂ , H ₂ O hydration reaction in the ternary system is represented by the following formula:

5.1.8 Phase

5MgO+MgCl ₂ +13H ₂ O＝5Mg(OH) ₂ ·MgCl ₂ ·8H ₂ O...(1)

3.1.8 phase

3MgO+MgCl ₂ +11H ₂ O＝3Mg(OH) ₂ ·MgCl ₂ ·8H ₂ O...(2)

The structure of phase 5.1.8 and phase 3.1.8 of magnesium oxychloride hydration phase is a chlorine-containing double salt, which is water-soluble. Under the condition of soaking in water, the hydration phase disintegrates to form Cl ions and Mg(OH ) ₂ Precipitation, which is also the main reason for the low softening coefficient and water resistance of magnesium oxychloride cement. The main hydration phase in the magnesium oxychloride cement hydration system is the 5.1.8 phase.

Contents of the invention

The object of the present invention is to aim at the defect of above-mentioned existence, propose a kind of hydraulic magnesium oxychloride cement composite material and preparation method thereof of highly active silicon oxide, magnesia, magnesium chloride system, through the modification of high active silicon oxide, aluminum oxide, The magnesium oxychloride cement composite material not only has the rapid hardening and early strength properties of magnesium oxychloride cementitious materials, but also has the hydraulic properties of magnesium silicate and magnesium aluminosilicate materials. Adding natural fibers, glass fibers, toughening The material, the interface modifier and the water-resistant agent make the material of the present invention have the properties of wood and other materials, and can replace wood and be applied to wood substitute materials, saving a large amount of natural wood resources.

The principle of the present invention is the utilization of highly reactive, amorphous silica and calcined kaolin-metakaolin. Under the action of high temperature in the production of ferrosilicon alloy, silicon dioxide (SiO ₂ ) decomposes to form silicon monoxide (SiO) gas escapes from the high-temperature furnace body and oxygen in the air to form submicron-scale silicon dioxide called silica fume, silica fume It has high chemical reactivity and pozzolanic activity. Kaolin (Al ₂ O ₃ , 2SiO ₂ , 2H ₂ O) is calcined at 700°C to 900°C to form metakaolin. The original layered kaolin decomposes to form amorphous SiO ₂ and Al ₂ O ₃ . Metakaolin has a very High chemical reactivity and pozzolanic activity. Adding silica fume or metakaolin to MgO-MgCl ₂ system can form part of hydraulic hydration products to modify magnesium oxychloride cement.

Magnesium oxide reacts with silica fume or with amorphous silica in metakaolin at room temperature, the hydrated phase MgO, nSiO ₂ , mH ₂ O has an amorphous structure, belongs to magnesium silicate gel, and has high structural strength . Magnesium oxide reacts with amorphous alumina in metakaolin at room temperature to form magnesium aluminosilicate MgO, xAl ₂ O ₃ , zSiO ₂ , yH ₂ O hydrated phase, which is equivalent to the position where aluminum replaces part of silicon, aluminum and silicon A replacement solid solution is formed, and the hydrated phase is an amorphous structure with gel properties. By adding sawdust filler material, adding short glass fiber reinforcement (short glass fiber length 3-5mm), adding interface modifier - aniline methyl triethyl silane, adding toughening materials such as 60-80 mesh rubber powder, adding Water-resistant agents such as phosphoric acid make the material of the present invention have wood properties and can be used instead of wood.

Technical solution of the present invention: silicon oxide, magnesium oxide, aluminum oxide, magnesium chloride composite material, characterized in that the composite material uses silica fume or calcined kaolin as the modified material of the magnesium oxychloride cement system, and the composite material has a main glue Concrete material, reinforcement material, toughening material, filling material, interface modifier, water resistance agent, the weight ratio between them is as follows:

Main gelling material: reinforcing material = 1: 0.01-0.03;

Main gelling material: filling material = 1: 0.04-0.25;

Main gelling material: interface modifier = 1: 0.001-0.003;

Main gelling material: toughening material = 1: 0.02-0.08;

Main gelling material:water repellant=1:0.002-0.006.

The preparation method of silicon oxide, magnesium oxide, aluminum oxide, and magnesium chloride-based composite materials is characterized in that the main gelling material is measured and prepared in proportion, and then sawdust filler material accounting for 4%-25% by weight of the main gelling material is added. 1%-3% by weight of the main gelling material short glass fiber reinforced material, adding an interface modifier accounting for 0.1%-0.3% by weight of the main gelling material, adding 2%-8% of the weight of the main gelling material for toughening agent, adding 0.2%-0.6% water-repelling agent accounting for the weight of the main gelling material; the above-mentioned components are mixed and stirred for 10-15 minutes to obtain the magnesium oxychloride-silicon composite material mixture, and then the above-mentioned mixture is poured into the mold at room temperature After molding, demould after 4-24 hours, take out the sample for natural curing.

The molar ratios of silica fume and metakaolin to magnesium oxide, magnesium chloride and water are respectively calculated according to the content of silicon oxide, and then converted into weight ratios after determining the molar ratios.

The mix ratio of the magnesium oxychloride-silicon composite material is calculated based on the molar ratio, and the molar ratio and weight ratio of each component can be converted to each other, and the calculation criteria are as follows;

Silica fume (SiO ₂ ): magnesium oxide: magnesium chloride: water = 0.05～1:6～13:1:4.8～11.3 (molar ratio) according to stoichiometric conversion weight ratio is

Silica fume (SiO ₂ ): magnesium oxide: magnesium chloride: water = 3 ~ 60: 240 ~ 520: 203: 87 ~ 203 (weight ratio) -----------(8)

SiO ₂ in metakaolin: magnesium oxide: magnesium chloride: water = 0.05～1:6～13:1:7.5～13.8 (molar ratio)------(9)

According to metakaolin stoichiometric conversion weight ratio is

Metakaolin: Magnesium Oxide: Magnesium Chloride: Water = 5.6～111: 240～520: 203: 135～248 (weight ratio) -----(9-1)

The mixture configured according to the above formula is called the main cementitious material.

Calculation of silica fume and metakaolin in formulas (8) and (9) is based on the actual silica content to calculate the number of moles. Since the mineral composition of kaolin is Al ₂ O ₃ , 2SiO ₂ , and 2H ₂ O, after activation and calcination, the crystal water will be lost. The silica and alumina in metakaolin have a fixed ratio, which can be calculated by measuring the content of SiO ₂ The content of metakaolin, therefore, in the molar ratio (see formulas 8 and 9), only the content of silicon dioxide is mainly calculated. In (8) formula, the concentration of magnesium chloride solution varies between 50%～70%, and in (9) formula, the concentration of magnesium chloride solution varies between 45%～60% (seeing annotated calculation examples).

The main cementitious material is measured and prepared according to the proportion, and then the sawdust filling material accounting for 4%-25% by weight of the main cementitious material is measured, and the short glass fiber reinforced material (short glass fiber length 3-5mm), the metering accounts for the interface modifier such as anilinomethyltriethylsilane of 0.1%-0.3% weight of the main gelling material, and the metering accounts for the toughening agent of 2%-8% of the main gelling material weight (such as 60-80 mesh rubber powder), and measure 0.2%-0.6% water-resistant agent such as phosphoric acid, which accounts for 0.2%-0.6% of the weight of the main gelling material.

Put measured silica fume or metakaolin, magnesia, sawdust, short glass fiber reinforced material (short glass fiber length 3-5mm), toughening material such as 60-80 mesh rubber powder into the mixer, dry mix and stir for 2-4 minutes to form a homogeneous dry mix.

The preparation of the magnesium chloride mixed solution is first prepared with magnesium chloride and water to form a magnesium chloride solution in proportion, then adding phosphoric acid and anilinomethyltriethylsilane to obtain a magnesium chloride mixed solution, and then adding the magnesium chloride mixed solution evenly into a mixer filled with a dry mixture, Stir for 5-10 minutes to obtain the magnesium oxychloride-silicon composite material mixture.

Then pour the stirred magnesium oxychloride-silicon composite material mixture into the mold at room temperature for molding, demould after 4-24 hours, take out the sample for natural curing. Use natural conservation, avoid rain, and after 7-28 days of conservation, the finished product will be obtained.

The invention has the advantages of abundant raw materials, good thermal stability of the magnesium oxychloride silicon composite material, and simple preparation process. After 28 days of natural curing, the room temperature flexural strength of the material is 20-30MPa, the compressive strength is 60-80MPa, the material density is 0.9-1.8g/cm3, and the elastic modulus is 50GPa. It can replace wood and save a lot of wood resources. Composite materials based on it can be used to make firewalls, fire doors, lightweight interior walls, indoor and outdoor decoration materials, advertising light boxes, chassis trays, packing box boards and other products.

Description of drawings

Accompanying drawing 1 is a kind of water-resistant magnesium oxychloride silicon composite material of the present invention and its preparation method in using silica fume as raw material flow chart.

Accompanying drawing 2 is a flow chart of using metakaolin as raw material in a water-resistant magnesium oxychloride silicon-based composite material and its preparation method of the present invention.

Detailed ways

Embodiment 1: adopt silica fume

Take the main gelling material silica fume (SiO ₂ ): magnesium oxide: magnesium chloride: water molar ratio of 0.05:7:1:4.8, converted into a weight ratio of 3:280:203:87, after simplified calculation, silica fume ( The weight percentage of SiO ₂ ): magnesium oxide: magnesium chloride: water is 0.5%: 48.85%: 35.45%: 15.18%. Take 1000Kg of the main gelling material, including 5Kg of silica fume (SiO ₂ ), 488.5Kg of magnesium oxide, 354.5Kg of magnesium chloride, and 151.8Kg of water. For external filling and reinforcing materials, take 40Kg of sawdust accounting for 4% of the main cementitious material, and take 10Kg of short glass fibers (specification 3mm) accounting for 1% of the main cementitious material. Get 2Kg of phosphoric acid accounting for 0.2% of the main gelling material, 1Kg of anilinomethyltriethylsilane accounting for 0.1% of the main gelling material, and 20Kg of 60-80 mesh rubber powder accounting for 2% of the main gelling material.

Mix and dissolve measured magnesium chloride 354.5Kg and water 151.8Kg to form a solution, then add measured phosphoric acid 2Kg and anilinomethyltriethylsilane 1Kg into the magnesium chloride solution and mix to obtain a magnesium chloride mixed solution for later use. First put the measured silica fume, magnesium oxide, sawdust, short glass fiber, and rubber powder into the mixer and dry mix for 2 minutes, then add the prepared magnesium chloride mixed solution and stir for 5 minutes to obtain a uniform mixture, pour it into the mold, and manually Tamp compactly. After 4 hours of indoor natural curing, the mold is demoulded, and after 7 to 28 days of natural curing, the finished product is obtained.

Embodiment 2: adopt silica fume

Take the main gelling material silica fume (SiO ₂ ): magnesium oxide: magnesium chloride: water molar ratio = 1: 13: 1: 11.3, converted into a weight ratio of 60: 520: 203: 203, after simplified calculation, silica fume The weight percentage of (SiO ₂ ):magnesium oxide:magnesium chloride:water is 6.1%:52.7%:20.6%:20.6%. Take 1000Kg of the main gelling material, including 61Kg of silica fume (SiO ₂ ), 527Kg of magnesium oxide, 206Kg of magnesium chloride, and 206Kg of water. For external filling and reinforcing materials, take 250Kg of sawdust accounting for 25% of the main cementitious material, and take 30Kg of short glass fibers (specification 5mm) accounting for 3% of the main cementitious material. Get 6Kg of phosphoric acid accounting for 0.6% of the main gelling material, 3Kg of anilinomethyltriethylsilane accounting for 0.3% of the main gelling material, and 80Kg of 60-80 mesh rubber powder accounting for 8% of the main gelling material.

Mix and dissolve 206Kg of measured magnesium chloride and 206Kg of water to form a solution for later use, then add 6Kg of measured phosphoric acid and 3Kg of anilinomethyltriethylsilane into the magnesium chloride solution and mix to obtain a magnesium chloride mixed solution for later use. First put the measured silica fume, magnesium oxide, sawdust and rubber powder into the mixer and dry mix for 4 minutes, then add the prepared magnesium chloride mixed solution and stir for 10 minutes to obtain a uniform mixture, pour it into the mold, and manually tamp and compact it. . After 24 hours of indoor natural curing, the mold is demoulded, and after 7 to 28 days of natural curing, the finished product is obtained.

Embodiment 3: adopt silica fume

Take the main gelling material silica fume (SiO ₂ ): magnesium oxide: magnesium chloride: water molar ratio = 0.75: 9.5: 1: 8.1, converted into a weight ratio of 45: 380: 203: 145.8, after simplification, silica fume ( The weight percentage of SiO ₂ ): magnesium oxide: magnesium chloride: water is 5.8%: 49.1%: 26.2%: 18.9%. Take 1000Kg of the main gelling material, including 58Kg of silica fume (SiO ₂ ), 491Kg of magnesium oxide, 262Kg of magnesium chloride, and 189Kg of water. For external filling and reinforcing materials, take 60Kg of sawdust accounting for 6% of the main cementitious material, and take 20Kg of short glass fibers (specification 5mm) accounting for 2% of the main cementitious material. Get 4Kg of 0.4% phosphoric acid as the main gelling material, 2Kg of 0.2% anilinomethyltriethylsilane as the main gelling material, and 50Kg of 60-80 mesh rubber powder accounting for 5% of the main gelling material.

Mix and dissolve 262Kg of measured magnesium chloride and 189Kg of water to form a solution, then add 4Kg of measured phosphoric acid and 2Kg of anilinomethyltriethylsilane into the magnesium chloride solution and mix to obtain a magnesium chloride mixed solution for later use. Put the measured silica fume, magnesium oxide, sawdust, short glass fiber and rubber powder into the mixer and dry mix for 3 minutes, then add the prepared magnesium chloride mixed solution and stir for 8 minutes to obtain a uniform mixture, pour it into the mold, and manually pound it Solid compact molding. After 12 hours of indoor natural curing, the mold will be demoulded, and after 7 to 28 days of curing, the finished product will be obtained.

Embodiment 4: adopt metakaolin

Get the _SiO2 in the main gelling material metakaolin: magnesium oxide: magnesium chloride: the molar ratio of water=0.05:6:1:7.5, convert the weight ratio into metakaolin: magnesium oxide: magnesium chloride: water=5.6:240:203 : 135, through simplification, metakaolin: magnesium oxide: magnesium chloride: the weight percent of water is 1.0%: 41.1%: 34.8%: 23.1%. Take 1000Kg of the main gelling material, including 10Kg of metakaolin, 411Kg of magnesium oxide, 348Kg of magnesium chloride, and 231Kg of water. Filling and reinforcing materials are added externally, 40Kg of sawdust accounting for 4% of the main cementitious material, 10Kg of short glass fiber (specification 3mm) accounting for 1% of the main cementitious material, 2Kg of phosphoric acid accounting for 0.2% of the main cementitious material, and accounting for the main gelling material The gelling material is 0.1% anilinomethyltriethylsilane 1Kg, and 20Kg of 60-80 mesh rubber powder accounting for 2% of the main gelling material is taken.

Mix and dissolve 348Kg of magnesium chloride and 231Kg of water to form a solution, then add 2Kg of phosphoric acid and 1Kg of anilinomethyltriethylsilane into the magnesium chloride solution and mix to obtain a mixed solution of magnesium chloride for later use. First put 10Kg of metakaolin, 411Kg of magnesium oxide, 40Kg of sawdust, 10Kg of short glass fiber and 20Kg of rubber powder into the mixer for 2 minutes, then add the prepared magnesium chloride solution and stir for 5 minutes to obtain a uniform mixture. The mold is compacted by manual tamping. After 4 hours of indoor natural curing, the mold is demoulded, and after 7 to 28 days of curing, the finished product is obtained.

Embodiment 5: adopt metakaolin

Get _SiO2 in the main gelling material metakaolin: magnesium oxide: magnesium chloride: the molar ratio of water=1: 13: 1: 13.8, convert into weight ratio and be metakaolin: magnesium oxide: magnesium chloride: water=111: 520: 203 : 248. After simplified calculation, the weight percentage of metakaolin: magnesium oxide: magnesium chloride: water is 10.2%: 48.1%: 18.8%: 22.9%. Take 1000Kg of the main gelling material, including 102Kg of metakaolin, 481Kg of magnesium oxide, 188Kg of magnesium chloride, and 229Kg of water. For external filling and reinforcing materials, take 250Kg of sawdust accounting for 25% of the main cementitious material, and 30Kg of short glass fiber (specification 5mm) accounting for 3% of the main cementitious material. External modifier, take 0.6% of the main gelling material phosphoric acid 6Kg, take 0.3% of the main gelling material aniline methyl triethyl silane 3Kg, take 80Kg of 60-80 mesh rubber powder accounting for 8% of the main gelling material .

Mix and dissolve the measured magnesium chloride 188Kg and water 229Kg to form a solution, then add the measured phosphoric acid 6Kg and anilinomethyltriethylsilane 3Kg into the magnesium chloride solution and mix to obtain a magnesium chloride mixed solution for later use. Put the measured metakaolin, magnesium oxide, sawdust, short glass fiber and rubber powder into the mixer and dry mix for 4 minutes, then add the prepared magnesium chloride mixed solution and stir for 10 minutes to obtain a uniform mixture, pour it into the mold, and manually Tamp compactly. After 24 hours of indoor natural curing, the mold will be demoulded, and after 7 to 28 days of curing, the finished product will be obtained.

Embodiment 6: adopt metakaolin

Get _SiO2 in the main gelling material metakaolin: magnesium oxide: magnesium chloride: the molar ratio of water=0.5:8.5:1:10.7, convert into weight ratio and be metakaolin: magnesium oxide: magnesium chloride: water=55.5:340:203 : 193. After simplified calculation, the weight percentage of metakaolin: magnesium oxide: magnesium chloride: water is 7%: 43%: 25.6%: 24.4%. Take 1000Kg of the main gelling material, including 7Kg of metakaolin, 430Kg of magnesium oxide, 256Kg of magnesium chloride, and 244Kg of water. For external mixing, take 70Kg of sawdust accounting for 7% of the main gelling material, and 20Kg of short glass fiber (specification 3mm) accounting for 2% of the main gelling material. Get 4Kg of 0.4% phosphoric acid as the main gelling material, 2Kg of 0.2% anilinomethyltriethylsilane as the main gelling material, and 50Kg of 60-80 mesh rubber powder accounting for 5% of the main gelling material.

Mix and dissolve 256Kg of magnesium chloride and 244Kg of water to form a solution, then add 4Kg of phosphoric acid and 2Kg of anilinomethyltriethylsilane into the magnesium chloride solution and mix to obtain a magnesium chloride mixed solution for later use. First put the measured metakaolin, magnesium oxide, sawdust, short glass fiber and rubber powder into the mixer and dry mix for 3 minutes, then add the prepared magnesium chloride solution and stir for 8 minutes to obtain a uniform mixture, pour it into the mold, and manually tamp it Dense molding. After 12 hours of indoor natural curing, the mold will be demoulded, and after 7 to 28 days of curing, the finished product will be obtained.

Note: Relevant data and calculation principles for the calculation of the mix ratio

1. The value of molar molecular weight

1. MgO _mol = 40 grams

2. MgCl ₂ 6H ₂ O _mol = 203 grams

3. MgCl ₂ =24+35.45×2=94.9 grams

4.6H ₂ O＝6×18＝108g

5. Metakaolin Al ₂ O ₃ 2SiO _2mol = 222 grams

6. Kaolin Al ₂ O ₃ 2SiO ₂ 2H ₂ O _mol = 258 grams

7. Al ₂ O _3mol = 102 grams

8. SiO _2mol = 60 grams

Two, magnesium chloride solution preparation

MgCl ₂ 6H ₂ O _mol = 203 grams

1. Calculation of the amount of water to be added to one mole of magnesium chloride in a 50% magnesium chloride solution:

MgCl ₂ 6H ₂ O _mol = 203 grams

H ₂ O = 203 grams, the number of moles is 11.3

One mole of magnesium chloride needs to add water = 203 grams

2. The calculation of adding water to one mole of magnesium chloride solution with a concentration of 70% magnesium chloride:

MgCl ₂ 6H ₂ O = 203g

A mole of magnesium chloride needs to add water = 203/.07-203 = 87 (grams)

H ₂ O = 87g, the number of moles of water to be added is 4.8

3. Calculate the amount of metakaolin added according to the number of moles of _SiO2 in metakaolin

1. SiO ₂ Weight percentage in metakaolin:

Metakaolin Al ₂ O ₃ ·2SiO ₂ /mol=222 g/mol

The weight percentage of SiO ₂ in metakaolin == SiO ₂ / metakaolin × 100% = 54%

0.05 moles of SiO ₂ is equivalent to grams of metakaolin = 0.05×60/0.54=5.55 grams

1 mole of _SiO2 is equivalent to the number of grams of metakaolin == 60/0.54 == 111 grams

Claims (2)

1. silicon oxide, magnesium oxide, aluminum oxide, magnesium chloride composite material, it is characterized in that material modified as the magnesia oxychloride cement system of this composite material by adopting silicon ash or calcined kaolin, this matrix material is by main gelling material, strongthener, toughening material, compaction material, interface modifier and water repellent agent are formed, and the weight ratio between them is as follows:

Main gelling material: strongthener=1: 0.01-0.03;

Main gelling material: compaction material=1: 0.04-0.25;

Main gelling material: interface modifier=1: 0.001-0.003;

Main gelling material: toughening material=1: 0.02-0.08;

Main gelling material: water repellent agent=1: 0.002-0.006;

Described main gelling material is by the silicon ash, magnesium oxide, magnesium chloride and water are formed, the silicon oxide in the silicon ash, magnesium oxide, the mol ratio of magnesium chloride and water is, silicon oxide in the silicon ash: magnesium oxide: magnesium chloride: water=0.05～1: 6～13: 1: 4.8～11.3, or the silicon oxide in the silicon ash in the described main gelling material, magnesium oxide, the weight ratio of magnesium chloride and water is the silicon oxide in the silicon ash: magnesium oxide: magnesium chloride: water=3～60: 240～520: 203: 87～203;

Or described main gelling material is by calcined kaolin, magnesium oxide, and magnesium chloride and water are formed, wherein the SiO in the calcined kaolin ₂, magnesium oxide, the mol ratio of magnesium chloride and water is the SiO in the calcined kaolin ₂: magnesium oxide: magnesium chloride: water=0.05～1: 6～13: 1: 7.5～13.8; Or calcined kaolin, magnesium oxide, the weight ratio of magnesium chloride and water is calcined kaolin: magnesium oxide: magnesium chloride: water=5.6～111: 240～520: 203: 135～248; Described interface modifier is the anilinomethyl triethyl silicane;

Described strongthener is the short glass fiber of length 3-5mm;

Described toughening material is 60～80 purpose rubber powders;

Described compaction material is a sawdust; Described water repellent agent is a phosphoric acid.

2. the preparation method of the described silicon oxide of claim 1, magnesium oxide, aluminum oxide, magnesium chloride composite material, it is characterized in that main gelling material is measured preparation in proportion, add the sawdust packing material that accounts for main gelling material 4%-25% weight then, add the short glass fiber strongthener that accounts for main gelling material 1%-3% weight, add the interface modifier that accounts for main gelling material 0.1%-0.3% weight, add the toughner that accounts for main gelling material weight 2%-8%, add the water repellent agent that accounts for main gelling material weight 0.2%-0.6%; Above-mentioned component obtained the chlorine oxygen magnesium silicon series composite material compound in 10-15 minute through mixing to stir, and more above-mentioned mixture was poured into normal temperature compacted under in the mould, and sample natural curing is taken out in the demoulding after 4-24 hour.

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