CN105819719B - A kind of enhanced geo-polymer and preparation method thereof - Google Patents

Abstract

The invention provides an enhanced geopolymer and a preparation method thereof, which uses raw materials such as phosphate and/or polyphosphate, higher levels, fly ash, water glass, alkaline compounds, silicon dioxide, water, etc., according to The parts by weight are blended, the raw materials are ground and mixed into a uniform slurry, the slurry is injected into a mold, and the product is obtained by curing at normal temperature or low temperature (20-80°C). The geopolymer product obtained by the formula and preparation method of the invention is resistant to high temperature and chemicals, has excellent mechanical properties, and its compressive strength reaches more than 150 MPa, meeting the requirements for use of building materials and high-temperature coatings. Compared with the traditional building material production process, the high-strength geopolymer preparation method of the present invention has the advantages of simple process, energy saving, environmental protection, low cost, easy operation and the like.

Description

A kind of reinforced geopolymer and its preparation method

technical field

The invention relates to a reinforced geopolymer and a preparation method thereof, and belongs to the field of inorganic non-metal gelling materials.

Background technique

Geopolymer is one of the inorganic non-metallic materials that has been studied very actively in the world in recent years. It is a new type of inorganic polymer material obtained by chemical reaction at relatively low temperature with clay, industrial waste residue or slag as the main raw material and alkali or acid as the activator. Geopolymers have unique properties superior to ordinary Portland cement, such as high strength, fast hardening, and acid and alkali corrosion resistance. At the same time, they have the advantages of abundant materials, low prices, and energy saving, which has aroused great interest from domestic and foreign material experts. .

The formation principle of geopolymer is mainly that the basic activator excites the silicon-aluminum source material, causing the break-recombination of the silicon-oxygen bond and the aluminum-oxygen bond to form an inorganic chain structure, which is similar to the formation of a chain structure by polymer polymerization. The polymerization reaction of geopolymer is as follows: under the action of alkali activator, the SiO ₂ and Al ₂ O ₃ covalent bonds in the silicon-aluminum source material are broken and broken, forming oligomeric silicon-oxygen tetrahedron and aluminum Oxygen tetrahedron; and then a polycondensation process, these oligomeric oxygen tetrahedrons and aluminum oxide tetrahedrons use water as the medium to recombine, discharge excess water, and form a new Si-O-Al network structure system. The three-dimensional network structure of geopolymer is composed of silicon-oxygen tetrahedrons and aluminum-oxygen tetrahedrons sharing bridge-oxygen bonds. This three-dimensional oxide network structure determines its excellent performance and thus its multi-purpose.

At present, the compressive strength of geopolymer materials is below 100 MPa, and other reinforcing agents are needed to strengthen geopolymers. The addition of other reinforcing agents not only increases the cost, but also complicates the processing technology.

Contents of the invention

The technical problem to be solved by the present invention is to provide a reinforced geopolymer and its preparation method in view of the above-mentioned deficiencies in the prior art. The geopolymer is formed at a temperature not exceeding 100°C and has high strength .

The technical scheme that the present invention adopts for solving the above-mentioned problem is:

An enhanced geopolymer, the raw materials of which include, in parts by weight, 10-80 parts of metakaolin, 0-40 parts of fly ash, 10-80 parts of water glass, 5-30 parts of basic compounds, carbon dioxide 0-50 parts of silicon, 5-30 parts of water, 0.1-2 parts of phosphate and/or polyphosphate.

According to the above scheme, the phosphate is one or more mixtures in arbitrary proportions among sodium dihydrogen phosphate, potassium dihydrogen phosphate, aluminum phosphate, etc.

According to the above scheme, the polyphosphate is a mixture of one or more of sodium tripolyphosphate and aluminum tripolyphosphate in any proportion.

According to the above scheme, the particle diameters of the metakaolin, fly ash and silicon dioxide are all no more than 250 mesh. Preferably, the particle diameters of the metakaolin, fly ash and silicon dioxide are in the range of 250-8000 mesh.

According to the above scheme, the water glass covers a variety of models in GB/T 4209-1996 "Industrial Water Glass", usually with a modulus of 1 to 4, which can be selected from liquid-1 water glass (modulus 3.5-3.7), liquid One of -2 water glass (modulus 3.1-3.4), liquid-3 water glass (modulus 2.6-2.9), liquid-4 water glass (modulus 2.2-2.5), etc.

According to the scheme, the basic compound is one of sodium hydroxide, potassium hydroxide and sodium carbonate.

In the preparation method of the above-mentioned enhanced geopolymer, the above-mentioned raw materials are stirred evenly to form a slurry, and then cured and shaped to obtain the enhanced geopolymer.

The preparation method of above-mentioned reinforced geopolymer specifically comprises the steps:

(1) In parts by weight, prepare 0.1-2 parts of raw material phosphate and or polyphosphate, 10-80 parts of metakaolin, 0-40 parts of fly ash, 10-80 parts of water glass, 5 parts of basic compound -30 parts, 0-50 parts of silicon dioxide, 5-30 parts of water;

(2) mixing the water glass prepared in step (1) with the basic compound, then leaving it to stand to obtain the alkali activator;

(3) phosphate and or polyphosphate prepared in step (1), and metakaolin, fly ash and silicon dioxide are mixed evenly (when the consumption of fly ash and or silicon dioxide in step (1) When it is 0, that is, there is no need to add fly ash and or silicon dioxide in this step), the alkali activator obtained in step (2) is added to grind and mix, and the water prepared in step (1) is added and mixed evenly to obtain a uniform slurry;

(4) Inject the homogeneous slurry obtained in step (3) into a mold, seal and react at 20-80° C. for 2-15 days to obtain the reinforced geopolymer.

According to the above scheme, use stirring and or ultrasound when mixing in step (2) until the mixture is uniform

According to the above scheme, the time of standing in step (2) is 1-2 days.

The invention utilizes phosphate or polyphosphate to hydrolyze to generate H ⁺ , promotes rapid hydrolysis of water glass to generate more hydroxide ions, and then promotes the disintegration of alumina and silica in metakaolin, so that Si-O and The Al-O covalent bond is broken and broken, and the [SiO ₄ ] ^4- and [AlO ₄ ] ^5- plasma groups are dissociated, and then repolymerized under the action of water and alkali to form a Si-O-Al-O space network structure . More importantly, the phosphate or polyphosphate that releases H ⁺ forms a water-insoluble double salt, thereby wrapping and fixing the free alkali metal ions. This double salt becomes the second phase and is evenly distributed in the In the geopolymer, the mechanical properties of the geopolymer are enhanced, and the geopolymer has better chemical resistance.

Compared with prior art, the beneficial effect of the present invention is:

1) In the reinforced geopolymer of the present invention, the second phase produced by the hydrolysis of phosphate or polyphosphate is uniformly dispersed in the geopolymer on a micro-nano scale, which enhances the mechanical properties of the geopolymer, Its compressive strength has reached above 150MPa.

2) The preparation method of the reinforced geopolymer of the present invention accelerates the destruction of the silicon-oxygen and aluminum-oxygen structures in the high territory and fly ash due to the hydrolysis catalysis of phosphate or polyphosphate, forming silicon -Oxygen-aluminum chain inorganic polymer structure, so the molding speed is fast, and it can be molded after 2-15 days of curing at room temperature or 20-80°C.

3) The geopolymer product obtained by the formula and preparation method of the present invention is high temperature resistant, chemical resistant, and has excellent mechanical properties, and its compressive strength reaches more than 150MPa, which meets the requirements of building materials and high temperature coatings . Compared with the traditional building material production process, the high-strength geopolymer preparation method of the present invention has the advantages of simple process, energy saving, environmental protection, low cost, easy operation and the like.

Description of drawings

FIG. 1 is a scanning electron micrograph of the reinforced geopolymer prepared in Example 1.

Detailed ways

In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with examples, but the present invention is not limited only to the following examples.

Example 1

A reinforced geopolymer, the raw materials of which include by weight parts: 0.1 part of sodium tripolyphosphate, 10 parts of 2000 mesh metakaolin, 10 parts of liquid-2 water glass (modulus 3.1-3.4), 5 parts of sodium hydroxide 5 parts, water 5 parts.

The preparation method of above-mentioned reinforced geopolymer specifically comprises the steps:

(1) In parts by weight, prepare 0.1 parts of sodium tripolyphosphate, 10 parts of 2000 mesh metakaolin, 10 parts of liquid-2 water glass (modulus 3.1-3.4), 5 parts of sodium hydroxide, and 5 parts of water;

(2) Mix the water glass prepared in step (1) with sodium hydroxide, stir and ultrasonically, then leave it for 24 hours to obtain an alkali activator;

(3) Mix the sodium tripolyphosphate and metakaolin prepared in step (1) evenly, add the alkali activator obtained in step (2) to grind and mix, and add the water prepared in step (1) and mix evenly to obtain uniform slurry;

(4) inject the homogeneous slurry obtained in step (3) into a mold, and seal and react at 20° C. for 15 days to obtain a reinforced geopolymer.

Compressive strength test:

The geopolymer with enhanced mechanical properties prepared in this example has a smooth surface and no cracks. The compressive strength test was carried out according to the test method for compressive strength of ceramic materials in GB/T-4740-1999, and its compressive strength was 151 MPa.

It can be seen from Figure 1 that in the process of preparing geopolymer from metakaolin, the polyphosphate is hydrolyzed to form the second phase phosphate, which is flower-shaped particles distributed in the geopolymer matrix, which has great influence on geopolymer The mechanical strength of the material can be improved.

Example 2

A kind of reinforced geopolymer, its raw material comprises by weight: 2 parts of sodium dihydrogen phosphate, 80 parts of 8000 mesh metakaolin, 80 parts of 8000 mesh fly ash, liquid-4 water glass (modulus 2.2-2.5 ) 80 parts, potassium hydroxide 30 parts, 8000 mesh silicon dioxide 50 parts, water 30 parts.

The preparation method of above-mentioned reinforced geopolymer specifically comprises the steps:

(1) In parts by weight, prepare 2 parts of sodium dihydrogen phosphate, 80 parts of 8000 mesh metakaolin, 80 parts of 8000 mesh fly ash, 80 parts of liquid-4 water glass (modulus 2.2-2.5), hydrogen 30 parts of potassium, 50 parts of 8000 mesh silica, 30 parts of water;

(2) mixing the water glass prepared in step (1) with potassium hydroxide, ultrasonicating after stirring, and then standing for 24 hours to obtain the alkali activator;

(3) Mix sodium dihydrogen phosphate prepared in step (1) with metakaolin, fly ash and silicon dioxide evenly, add the alkali activator obtained in step (2) to grind and mix, and add step (1) at the same time Mix the prepared water to obtain a uniform slurry;

(4) The homogeneous slurry obtained in step (3) is injected into a mold, sealed and reacted at 80° C. for 2 days, and the reinforced geopolymer can be obtained.

Compressive strength test:

The geopolymer with enhanced mechanical properties prepared in this example has a smooth surface and no cracks. The compressive strength test was carried out according to the test method for compressive strength of ceramic materials in GB/T-4740-1999, and its compressive strength was 153 MPa.

Example 3

A reinforced geopolymer, the raw materials of which include, in parts by weight, 0.4 parts of aluminum tripolyphosphate, 41 parts of 250 mesh metakaolin, 43 parts of liquid-1 water glass (modulus 3.5-3.7), and 6 parts of sodium carbonate , 1 part of 250 mesh silicon dioxide, 9 parts of water.

The preparation method of above-mentioned reinforced geopolymer specifically comprises the steps:

(1) In parts by weight, prepare 0.4 parts of aluminum tripolyphosphate, 41 parts of 250-mesh metakaolin, 43 parts of liquid-1 water glass (modulus 3.5-3.7), 6 parts of sodium carbonate, and 250-mesh silica 1 part, 9 parts of water;

(2) Mix the water glass prepared in step (1) with sodium carbonate, ultrasonically stir after stirring, and then let stand for 24 hours to obtain the alkali activator;

(3) Mix the aluminum tripolyphosphate prepared in step (1) with metakaolin and silicon dioxide evenly, add the alkali activator obtained in step (2) to grind and mix, and add the water prepared in step (1) at the same time Mix well to obtain a uniform slurry;

(4) inject the homogeneous slurry obtained in step (3) into a mold, and seal and react at 50° C. for 10 days to obtain a reinforced geopolymer.

Compressive strength test:

The surface of the geopolymer with enhanced mechanical properties prepared in this example is smooth and free of cracks. The compressive strength test is carried out according to the test method for compressive strength of ceramic materials in GB/T-4740-1999, and its compressive strength is 159 MPa.

Example 4

A kind of enhanced geopolymer, its raw material comprises by weight: 1 part of potassium dihydrogen phosphate, 50 parts of 800 mesh metakaolin, 10 parts of 800 mesh fly ash, liquid-3 water glass (modulus 2.6-2.9 ) 43 parts, potassium hydroxide 10 parts, water 10 parts.

The preparation method of above-mentioned reinforced geopolymer specifically comprises the steps:

(1) In parts by weight, prepare 1 part of potassium dihydrogen phosphate raw materials, 50 parts of 800 mesh metakaolin, 10 parts of 800 mesh fly ash, 43 parts of liquid-3 water glass (modulus 2.6-2.9), Potassium 10 parts, water 10 parts;

(2) mixing the water glass prepared in step (1) with potassium hydroxide, ultrasonicating after stirring, and then standing for 24 hours to obtain the alkali activator;

(3) Mix potassium dihydrogen phosphate prepared in step (1) with metakaolin and fly ash evenly, add the alkali activator obtained in step (2) to grind and mix, and add the water prepared in step (1) at the same time Mix well to obtain a uniform slurry;

(4) The homogeneous slurry obtained in step (3) is injected into a mold, sealed and reacted at 70° C. for 7 days, and the reinforced geopolymer can be obtained.

Compressive strength test:

The geopolymer with enhanced mechanical properties prepared in this example has a smooth surface and no cracks. The compressive strength test is carried out according to the test method for compressive strength of ceramic materials in GB/T-4740-1999, and its compressive strength is 155 MPa.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the creative concept of the present invention, some improvements and changes can also be made, and these all belong to the present invention scope of protection.

Claims (9)

1. a kind of enhanced geo-polymer, it is characterised in that its raw materials by weight portion meter includes：Phosphate and/or poly 0.1-2 parts of phosphate, 10-80 parts of metakaolin, 0-40 parts of flyash, 10-80 parts of waterglass, 5-30 parts of alkali compounds, two 0-50 parts of silica, 5-30 parts of water.

2. a kind of enhanced geo-polymer according to claim 1, it is characterised in that the phosphate is biphosphate One or more of mixtures in any proportion in sodium, potassium dihydrogen phosphate, aluminum phosphate.

3. a kind of enhanced geo-polymer according to claim 1, it is characterised in that the polyphosphate is trimerization The mixture of one or both of sodium phosphate and aluminium triphosphate in any proportion.

A kind of 4. enhanced geo-polymer according to claim 1, it is characterised in that the metakaolin, flyash, The particle diameter of silica is no more than 250 mesh.

A kind of 5. enhanced geo-polymer according to claim 4, it is characterised in that the metakaolin, flyash, The particle diameter of silica is in the range of 250 ~ 8000 mesh.

6. a kind of enhanced geo-polymer according to claim 1, it is characterised in that the waterglass is industry water glass Glass, modulus are 1 ~ 4.

7. a kind of enhanced geo-polymer according to claim 1, it is characterised in that the alkali compounds is hydrogen-oxygen Change one or more of mixtures in any proportion in sodium, potassium hydroxide and sodium carbonate.

8. the preparation method of the enhanced geo-polymer described in any one in claim 1-7, it is characterised in that The raw material is stirred evenly as shaping is conserved after slurry, you can obtain enhanced geo-polymer.

9. the preparation method of the enhanced geo-polymer described in any one in claim 1-7, it is characterised in that Include the following steps：

（1）Count in parts by weight, prepare raw material phosphate and/or 0.1-2 parts of polyphosphate, 10-80 parts of metakaolin, fine coal 0-40 parts grey, 10-80 parts of waterglass, 5-30 parts of alkali compounds, 0-50 parts of silica, 5-30 parts of water；

（2）By step（1）Ready waterglass and alkali compounds mixing, it is ultrasonic after stirring, then stand and obtain alkali-activated carbonatite Agent；

（3）By step（1）Ready phosphate and/or polyphosphate, and metakaolin, flyash and silica mix Close uniformly, add step thereto（2）Obtained alkali-activator ground and mixed, while add step（1）Ready water mixes, Obtain uniform sizing material；

（4）By step（3）Gained uniform sizing material injects mould, sealing reaction 2-15 days at 20-80 DEG C, you can strengthened Type geo-polymer.