CN111302682A

CN111302682A - Alkali activation slurry containing alkali activation liquid and inorganic powder

Info

Publication number: CN111302682A
Application number: CN201911297500.5A
Authority: CN
Inventors: 李韦皞; 郑大伟
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-12-17
Filing date: 2019-12-17
Publication date: 2020-06-19

Abstract

The invention discloses alkali activation slurry containing alkali activation liquid and inorganic powder, which comprises inorganic powder and alkali activation liquid, wherein the inorganic powder comprises silicate compounds, the alkali activation liquid is prepared by mixing an alkali activating agent and water, and the alkali activating agent is prepared by one or more of alkali metal hydroxide, alkali metal silicate or silica gel and one or more of alkali metal aluminate or aluminum powder; the molar ratio of silicon dioxide to metal oxide of the alkali activating solution is between 0.25 and 0.5, and the molar ratio of silicon dioxide to aluminum oxide is between 20 and 100. The invention uses the slurry prepared from inorganic powder after alkali activation as a bonding material, not only can be independently used as a reinforcing material or a fireproof material, but also can be added with a proper amount of coarse and fine aggregates to form mortar or concrete to replace the traditional cement slurry for construction materials.

Description

Alkali activation slurry containing alkali activation liquid and inorganic powder

Technical Field

The invention belongs to the technical field of building materials, and particularly relates to alkali activation slurry containing alkali activation liquid and inorganic powder.

Background

In recent years, due to rapid development of industrial production and urban construction, a large amount of carbon dioxide is discharged, the carbon dioxide discharged in large amount can be accumulated in the atmosphere because the carbon dioxide cannot be absorbed by the ocean and the forest, and the more the carbon dioxide is accumulated in the atmosphere, the more the air temperature is increased; the more the air temperature is increased, the more carbon dioxide is left in the atmosphere, thus forming a vicious circle and causing pollution to the earth environment and increasing the greenhouse effect; among them, the most important industries for generating carbon dioxide emission are the cement industry, except steel making and coal-fired power generation.

Cement is an important industry for global construction and economic development, but the traditional cement slurry is prepared by baking calcium carbonate at high temperature, so that a large amount of energy is consumed in the production process, and a large amount of carbon dioxide is generated; generally, 880 kg of carbon dioxide is discharged when 1 metric ton of cement is produced, and if the annual domestic cement production is about 21 hundred million metric tons, the annual domestic carbon dioxide production amount for cement production is more than 18 hundred million metric tons. The total greenhouse gas emission amount in China is ranked 1 st in the world and accounts for nearly 28% of the world, so how to actively reduce the greenhouse gas emission amount of each industry is one of the important environmental protection subjects at present.

Therefore, it is an urgent problem to develop a new material that can replace the conventional cement slurry, and does not consume a large amount of energy and generate carbon dioxide during the production process.

Disclosure of Invention

In order to solve the technical problems, the invention provides alkali activation slurry containing alkali activation liquid and inorganic powder.

In order to achieve the purpose, the invention provides the following technical scheme:

an alkali activation slurry containing alkali activation liquid and inorganic powder comprises inorganic powder and alkali activation liquid, wherein,

the inorganic powder comprises silicate compounds, and the inorganic powder comprises silicate compounds,

the alkali activating solution is prepared by mixing an alkali activating agent and water, wherein the alkali activating agent is prepared by one or more of alkali metal hydroxide, alkali metal silicate or silica gel and one or more of alkali metal aluminate or aluminum powder;

the molar ratio of silicon dioxide to metal oxide of the alkali activating solution is between 0.25 and 0.5, and the molar ratio of silicon dioxide to aluminum oxide is between 20 and 100.

Further, the inorganic powder includes an amorphous silicate compound.

Further, the inorganic powder comprises one or more of glass, fly ash, clay slag, waste soil or sludge.

Further, the alkali metal aluminate is selected from sodium aluminate or potassium aluminate, and the alkali metal hydroxide and the alkali metal silicate are selected from sodium silicate, potassium silicate, sodium hydroxide or potassium hydroxide.

Further, the mole ratio of silicon dioxide to alkali metal oxide (SiO2/M2O) of the alkali activating solution is between 0.375 and 0.5, and the mole ratio of silicon dioxide to aluminum oxide (SiO2/Al2O3) of the alkali activating solution is between 20 and 80.

Further, the mole ratio of silicon dioxide to alkali metal oxide (SiO2/M2O) of the alkali activating solution is between 0.375 and 0.5, and the mole ratio of silicon dioxide to aluminum oxide (SiO2/Al2O3) of the alkali activating solution is between 40 and 60.

Further, the weight ratio (hereinafter referred to as liquid/solid ratio) of the alkali activation liquid to the inorganic powder is between 1 and 0.5.

Further, the liquid/solid ratio of the alkali activation liquid to the inorganic powder is between 1 and 0.67, and the viscosity of the alkali activation slurry is 10,000-60,000 mPas.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention relates to alkali activation slurry containing alkali activation liquid and inorganic powder, which adopts different types of industrial byproducts as reacted inorganic powder, and forms a cement-like cementing material after adding the alkali activation liquid to react with the reacted inorganic powder. Because a high-temperature kiln burning process flow of cement is not needed, the emission of carbon dioxide can be greatly reduced, and the reacted inorganic powder does not need to be additionally mined from a mine, so that the consumption of natural resources can be reduced, and the emission of the carbon dioxide can be greatly reduced through the development of the technology.

2. The alkali activation slurry containing alkali activation liquid and inorganic powder of the invention utilizes the slurry prepared from the inorganic powder after alkali activation as a bonding material, not only can be used for reinforcing materials or fireproof materials independently, but also can be used for forming mortar or concrete after adding a proper amount of coarse and fine aggregates to replace the traditional cement slurry for building materials.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

the inorganic powder comprises a silicate compound,

the alkali activating solution is prepared by mixing an alkali activating agent and water, wherein the alkali activating agent is prepared by one or more of alkali metal hydroxide, alkali metal silicate or silica gel and one or more of alkali metal aluminate or aluminum powder; the molar ratio of silicon dioxide to metal oxide (SiO2/M2O, M is alkali metal element) of the alkali activating solution is between 0.25 and 0.5, and the molar ratio of silicon dioxide to aluminum oxide (SiO2/Al2O3) is between 20 and 100.

At normal temperature, water, acid, alkali, salt and other substances only have direct damage effect on the network structure of the silicate substance; the stronger the alkalinity and the higher the temperature, the more likely the chain scission of the silicate network structure is caused. In general, crystalline materials have low activity, while amorphous materials have high activity due to incomplete structure, and in order to effectively generate chemical activity to crystalline or amorphous silicate, it is necessary to destroy Si-O-Si and/or Si-O-Al network structure with high alkaline solution, so as to disaggregate and break down the network aggregates on the particle surface, and form active substances such as monomers or dimers of silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron, thereby improving the chemical activity, and these SiO4 and AlO4 tetrahedrons are subjected to dehydration, condensation, hardening, and other processes again, and then are polymerized and bonded again to form a cementing material.

However, if the amount of the SiO4 and AlO4 monomers dissolved from the surface of the silicate by the high alkaline solution is too small, the strength of the cementitious material will be insufficient due to the incomplete structure, so the invention not only uses alkali metal hydroxide, alkali metal silicate and/or silica gel to control the alkalinity of the alkali activation solution, but also further uses alkali metal aluminate or aluminum powder to control the aluminum content of the alkali activation solution, and supplements the required AlO4 monomers according to the actual situation, so as to not only make up the disadvantage of insufficient amount of AlO4 monomers dissolved from the surface of the inorganic powder by the high alkaline solution, but also make up for the inorganic powder when using general aluminum-free silicate compounds or silicate compounds with very low aluminum content, such as glass, and can be used normally, not only make the cementitious material structure more complete by adding aluminum and further enhance the strength, but also is not limited by the kind of the used materials, but may have a wider choice of materials.

The invention uses the slurry prepared from inorganic powder activated by alkali as a bonding material, not only can be independently used as a reinforcing material or a fireproof material, but also can be added with a proper amount of coarse and fine aggregates to form mortar or concrete to replace the traditional cement slurry for construction materials.

Example 2

This embodiment is substantially the same as embodiment 1, except that the inorganic powder used comprises an amorphous silicate compound, and the inorganic powder suitable for this preferred embodiment of the present invention comprises glass, such as: glass powder, waste glass, glass fibers, fly ash, for example: fly ash, coal-fired bottom ash, incineration fly ash, incineration bottom ash, volcanic ash, clay, various slag, various waste soils, sludge and other silicate compounds, and can be used in a single or composite mode.

Example 3

This example is essentially the same as example 1 or example 2, except that the alkali metal aluminate used is selected from sodium aluminate or potassium aluminate, and the alkali metal hydroxide and the alkali metal silicate are selected from sodium silicate, potassium silicate, sodium hydroxide or potassium hydroxide.

Example 4

This embodiment is substantially the same as the above embodiment, except that when the alkalinity (M2O) is too high, sodium bicarbonate crystals (also known as white sodium carbonate) formed by the reaction of alkali metal with moisture and carbon dioxide in the air are formed on the surface of the product made from the slurry, and the too high alkalinity will destroy the formed bonds to reduce the strength; when the alkalinity is insufficient, the reactivity is too low, the strength of the finished product prepared from the slurry is insufficient,

therefore, preferably, the molar ratio of silicon dioxide to alkali metal oxide (SiO2/M2O) of the alkali activating solution is between 0.375 and 0.5, and the molar ratio of silicon dioxide to aluminum oxide (SiO2/Al2O3) is between 20 and 80; more preferably, the molar ratio of silicon dioxide to alkali metal oxide (SiO2/M2O) of the alkali activating solution is between 0.375 and 0.5, and the molar ratio of silicon dioxide to aluminum oxide (SiO2/Al2O3) is between 40 and 60.

Example 5

This example is substantially the same as the above examples, except that when the viscosity of the alkali-activated slurry is too low, the fluidity is too high, and the slurry tends to cause a sagging phenomenon due to its own weight during use, and when the viscosity is too high, the alkali-activated slurry tends to be difficult to stir, and the alkali-activation reaction is not complete.

Therefore, the weight ratio (hereinafter referred to as liquid/solid ratio) of the alkali activating solution to the inorganic powder is between 1 and 0.5. The liquid/solid ratio of the alkali activation liquid to the inorganic powder is between 1 and 0.67, and the viscosity of the alkali activation slurry is 10,000-60,000 mPas.

When the alkali activated slurry is further mixed with coarse and fine aggregates to form mortar or concrete, the mortar or concrete can be used as a construction material, not only can partially or completely replace the traditional cement, but also because the used inorganic material can be crystalline and amorphous raw materials or wastes, the cement is prepared by firstly firing calcium carbonate at high temperature without the need of the traditional cement, and the mortar or concrete has the functions of saving energy and reducing carbon.

Example 6

This example further verifies the present application with 16 test samples and 4 comparative samples.

Test specimen 1

Firstly weighing water-quenched blast furnace slag powder as an inorganic powder raw material, adding sodium hydroxide, sodium silicate and sodium aluminate into water, stirring and mixing uniformly to obtain an alkali activation solution, controlling the molar ratio of SiO2/Na2O of the alkali activation solution to be 0.5, the molar ratio of SiO2/Al2O3 to be 20 and the liquid/solid ratio of the inorganic powder to the alkali activation solution to be 1.0, then adding the alkali activation solution into the inorganic powder, stirring, and forming the alkali activation solution and the inorganic powder into uniform slurry to obtain the alkali activation slurry.

Then, the alkali-activated slurry was molded into a cylindrical sample having a size of 5cm × 10cm to obtain test specimen No. 1, which was subjected to a strength test.

Test specimens 2 to 5

The kind and production method of the inorganic powder used were substantially the same as those of test sample 1, and the difference was that the molar ratio between SiO2/Na2O and SiO2/Al2O3 was different. Specific ratios are detailed in table 1.

Test specimens 6 to 16

The preparation method of the alkali-activated slurry in this embodiment is substantially the same as that of test sample 1, except that the inorganic powder used in this embodiment is obtained by mixing water-quenched blast furnace slag powder, fly ash and/or glass powder in different proportions, and the molar ratio between SiO2/Na2O and SiO2/Al2O3 is also different. Specific ratios are detailed in table 1.

Comparative samples 1 to 4

Comparative samples 1 to 4 of the alkali-activated slurry of the present invention and samples prepared from the alkali-activated slurries of the comparative samples 1 to 4 were prepared in substantially the same manner as in test sample 1, except that no sodium aluminate Al2O3 was added to the alkali-activated solutions of the comparative samples 1 to 4.

The composition types and the proportions of the alkali-activated slurries of the test samples 1 to 16 of the present invention and the comparative samples 1 to 4, and the results of the 28-day compressive strengths of the samples obtained therefrom are shown in tables 1 and 2, respectively.

TABLE 1

TABLE 2

As can be seen from the results in tables 1 and 2, when no sodium aluminate is added to the alkali activation solution, the 28-day compressive strength of the prepared sample is poor, and when the molar ratios of SiO2/Na2O and SiO2/Al2O3 of the alkali activation solution are controlled to be between 0.25-0.5 and 20-100, the 28-day compressive strength of the prepared sample from the alkali activation slurry prepared from different inorganic powders can reach 10 MPa;

when the molar ratio of SiO2/Al2O3 of the alkali activation solution is controlled to be between 20 and 80, the 28-day compressive strength of the sample prepared from the alkali activation slurry can reach more than 15MPa, and when the molar ratio of SiO2/Na2O of the alkali activation solution is further controlled to be between 0.375 and 0.5 and the molar ratio of SiO2/Al2O3 is controlled to be between 40 and 60, the 28-day compressive strength of the sample prepared from the alkali activation slurry can be more than 25 MPa.

The invention utilizes the cementing material formed by alkali activation slurry, besides controlling the alkalinity of the alkali activation solution by alkali metal hydroxide and alkali metal silicate, further, the aluminum content of the alkali activation solution is regulated by the alkali metal aluminate, the required AlO4 monomer is added according to the actual situation, the structure of the cementing material is more complete by the addition of aluminum, thereby enhancing the strength of the cementing material, and the cementing material is not limited by the type of the material used, and has wider material selection, so that the cement slurry is not required to be prepared after calcium carbonate is fired at high temperature like the traditional cement slurry, has the functions of saving energy and reducing carbon, the alkali activated slurry can be used for reinforcing materials or fireproof materials independently, and can also be used for building materials by replacing the traditional cement slurry to form mortar or concrete after adding a proper amount of coarse and fine aggregates, so that the aim of the invention can be achieved.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that various changes, modifications and substitutions can be made without departing from the spirit and scope of the invention as defined by the appended claims. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An alkali activation slurry containing an alkali activation solution and an inorganic powder, characterized in that: comprises inorganic powder and alkali activating liquid, wherein,

the inorganic powder comprises silicate compounds;

2. The alkali-activated slurry according to claim 1, wherein the inorganic powder includes an amorphous silicate compound.

3. The alkali-activated slurry of claim 1, wherein the inorganic powder comprises one or more of glass, fly ash, clay slag, waste soil, and sludge.

4. The alkali-activated slurry of claim 1, wherein said alkali metal aluminate is selected from sodium aluminate and potassium aluminate, and said alkali metal hydroxide and said alkali metal silicate are selected from sodium silicate, potassium silicate, sodium hydroxide and potassium hydroxide.

5. The alkali-activated slurry of claim 1, wherein the molar ratio of silica to alkali metal oxide in the alkali-activated solution is 0.375-0.5, and the molar ratio of silica to alumina in the alkali-activated solution is 20-80.

6. The alkali-activated slurry of claim 1, wherein the molar ratio of silica to alkali metal oxide in the alkali-activated solution is 0.375-0.5, and the molar ratio of silica to alumina in the alkali-activated solution is 40-60.

7. The alkali-activated slurry according to claim 1, wherein a weight ratio of the alkali-activated liquid to the inorganic powder is 1 to 0.5.

8. The alkali-activated slurry as claimed in claim 1, wherein the liquid/solid ratio of the alkali-activated liquid to the inorganic powder is between 1-0.67, and the viscosity of the alkali-activated slurry is 10,000-.