CN114605121A

CN114605121A - Tungsten tailing autoclaved aerated concrete and preparation method thereof

Info

Publication number: CN114605121A
Application number: CN202210307150.1A
Authority: CN
Inventors: 黄海智
Original assignee: China Resources Cement Technology R&D Co Ltd
Current assignee: China Resources Cement Technology R&D Co Ltd
Priority date: 2022-03-25
Filing date: 2022-03-25
Publication date: 2022-06-10
Anticipated expiration: 2042-03-25
Also published as: CN114605121B

Abstract

The invention discloses a tungsten tailing autoclaved aerated concrete and a preparation method thereof, which solve the problem of tungsten tailing stockpiling in the prior art, are directly used for manufacturing the autoclaved aerated concrete and have low SiO content₂The strength of the autoclaved aerated concrete is lower under the condition. The mortar comprises 50-75% of sand material, 5-25% of quicklime, 10-30% of cementing material, 0.1-2% of water reducing agent, 1-5% of dihydrate gypsum, 1.1-5% of additive, 0.1-2% of aluminum potassium sulfate dodecahydrate and 0.1-1% of aluminum powder paste, wherein the additive is any one or two of sodium dodecyl sulfate and water glass; the sand material comprises tungsten tailings and quartz sand, wherein the mass percentage of the tungsten tailings in the sand material is 50-100%. After the tungsten tailings are added, the steam pressurized concrete prepared by the invention can also generate the aluminum-substituted tobermorite, further improve the strength of the product, greatly reduce the production cost of the steam pressurized concrete, save a large amount of natural resources and eliminate the waste of the steam pressurized concreteAnd a large amount of tailings are treated, and the environmental load is reduced.

Description

Tungsten tailing autoclaved aerated concrete and preparation method thereof

Technical Field

The invention relates to the field of steam concrete manufacturing, in particular to tungsten tailing autoclaved aerated concrete and a preparation method thereof.

Background

The tungsten ore in China has low grade, the tungsten ore generates huge amount of tailings in the ore dressing process, the yield exceeds 95 percent, and great resource waste is caused. According to statistics, more than 100 million tons of tungsten tailings are newly added every year in China. The existing stock of the existing old tungsten tailing dam exceeds thousands of tons, the tungsten tailing dam has the risks of wide occupied area, pollution to ecological environment, harm to human health, easy initiation of geological disasters and the like, and a method capable of consuming a large amount of tungsten tailings is urgently needed to be found; meanwhile, a large amount of useful minerals contained in the tailings are not fully utilized, so that precious mineral resources are seriously wasted, and great challenges are brought to the sustainable development of mines.

The autoclaved aerated concrete is a light green building wall material prepared by adding aluminum powder into siliceous materials such as quartz sand and calcareous materials such as cement, gypsum and lime to generate hydrogen and curing the hydrogen at high temperature and high pressure under saturated steam. The autoclaved aerated concrete has the advantages of small volume weight, sound insulation, heat preservation and the like, is vigorously developed in many countries as a novel green building material, and is widely applied to non-bearing floor panels and wall panels of various buildings.

At present, siliceous materials for producing autoclaved aerated concrete mainly come from sand, pebbles and gravels in rivers or from sandstone aggregates mined and processed in quartz mines. Due to the large volume of mining, these resources are rapidly depleting; exploitation of these resources not only destroys the natural environment and the riverbed ecology, but also poses serious challenges to the ecological environment of the origin and sustainable development. Meanwhile, as the country further tightens up the management and control of mine resources, not only the resource acquisition difficulty increases year by year, but also the raw material purchasing cost greatly rises.

However, the prior autoclaved aerated concrete technology requires SiO of siliceous material₂The content is required to be more than 70 percent, otherwise, the produced product usually has the situation of unqualified strength. While SiO of tungsten tailings₂The content is usually low (less than 50% in most cases), and the application of the tungsten tailings in the production of autoclaved aerated concrete is greatly limited.

Disclosure of Invention

The invention aims to provide a tungsten tailing autoclaved aerated concrete and a preparation method thereof, aiming at solving the problem that in the prior art, tungsten tailings are piled up and directly used for manufacturing the autoclaved aerated concrete, and the low-SiO content aerated concrete is low in SiO content₂The strength of the autoclaved aerated concrete is lower under the condition.

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

the invention provides a tungsten tailing autoclaved aerated concrete which comprises the following components in percentage by mass: 50-75% of sand material, 5-25% of quicklime, 10-30% of cementing material, 0.1-2% of water reducing agent, 1-5% of dihydrate gypsum, 1.1-5% of additive, 0.1-2% of aluminum potassium sulfate dodecahydrate and 0.1-1% of aluminum powder paste, wherein the additive is any one or two of sodium dodecyl sulfate and water glass;

the sand material comprises tungsten tailings and quartz sand, the mass percent of the tungsten tailings in the sand material is 50-100%, and the tungsten tailings are SiO₂Less than 50% by mass, Al₂O₃The mass fraction is less than 13 percent.

Optionally or preferably, the quicklime has a digestion speed of more than 10min, a digestion temperature of more than 50 ℃ and a calcium oxide content of more than 60%.

Alternatively or preferably, the cementitious material comprises either or both of portland cement and sulphoaluminate cement.

Optionally or preferably, the water reducing agent is one or two of a naphthalene water reducing agent and a polycarboxylic acid water reducing agent.

Alternatively or preferably, the SiO in the quartz sand₂Content > 70%, SiO₂The particle size is 15-75 μm.

Optionally or preferably, the dihydrate gypsum is any one or more of natural gypsum, desulfurized gypsum and phosphogypsum.

Alternatively or preferably, the water glass is a sodium silicate solution, the modulus of the sodium silicate solution is more than 1, and the mass fraction of the sodium silicate solution is more than 20%.

Optionally or preferably, the aluminum potassium sulfate dodecahydrate contains more than 90% of effective components, and the pH value is 2.5-6.5.

Alternatively or preferably, the sodium lauryl sulfate has an active content of > 30%, petroleum ether solubles of greater than 1%, and an inorganic salt content of less than 10%.

The invention provides a preparation method of tungsten tailing autoclaved aerated concrete, which comprises the following preparation steps:

s1, dehydrating and drying the tungsten tailings, grinding the tungsten tailings by a ball milling process, and sieving the tungsten tailings to obtain a part with the particle size less than 0.075 mm;

s2, adding quicklime, a cementing material, dihydrate gypsum, quartz sand and water in sequence, stirring to prepare slurry, then continuously adding aluminum powder paste, sodium dodecyl sulfate and aluminum potassium sulfate dodecahydrate into the slurry, wherein the water-material ratio in the slurry is 0.3-0.7, adding water glass and a water reducing agent according to the expansion degree of the slurry, then injecting into a mold, performing pre-curing, and then performing cutting, autoclaved curing and drying processes to prepare a finished product.

Based on the technical scheme, the embodiment of the invention can at least produce the following technical effects:

(1) according to the tungsten tailing autoclaved aerated concrete and the preparation method thereof, provided by the invention, quartz sand used in the production process of the traditional autoclaved aerated concrete is replaced by the tungsten tailings, the replacement amount can be dynamically adjusted according to production requirements, the maximum replacement amount can reach 100%, the tungsten tailings can be massively digested and stockpiled, the stockpiling problem of the tungsten tailings is effectively relieved, the strength of a product is qualified, and the tungsten tailings are endowed with the possibility of secondary utilization as a resource. The tungsten tailings of the application are SiO₂Lower content, but Al₂O₃The content of the aluminum-silicon-aluminum alloy is about 10 percent higher than that of common quartz sand, and XRD results show that under the conditions of constant silicon content and high aluminum content, aluminum atoms can pass through a substituted silicon-oxygen tetrahedron structure (Q) in the autoclave reaction process³Structure) to form an AlO Torbei mullite crystal, wherein a sample A, C in figure 1 is a 002 crystal form diffraction peak of Torbei mullite, and a sample B is a sample added with Al₂O₃The Tolbecco mullite diffraction peak of (A) can be observed to have a significant left shift compared with the upper and lower peaks due to the substitution of aluminum atoms, the silicon-oxygen tetrahedron (Q)³Structure) appears the phenomenon of crystal form enlargement, which proves that under the condition of higher aluminum content, the tobermorite is generated instead of the tobermorite, and the strength of the product can be further improved. The production cost of the steam pressurized concrete is greatly reduced, a large amount of natural resources can be saved, a large amount of tailings can be digested, the environmental load is reduced, waste is turned into wealth, and sustainable development of industry and social economy is realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

Figure 1 is an XRD examination of a product of an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a tungsten tailing autoclaved aerated concrete which comprises the following components in percentage by mass:

50-75% of sand material, 5-25% of quicklime, 10-30% of cementing material, 0.1-2% of water reducing agent, 1-5% of dihydrate gypsum, 1.1-5% of additive, 0.1-2% of aluminum potassium sulfate dodecahydrate and 0.1-1% of aluminum powder paste, wherein the additive is any one or two of sodium dodecyl sulfate and water glass;

the sand material comprises tungsten tailings and quartz sand, the mass percent of the tungsten tailings in the sand material is 50-100%, and the tungsten tailings are SiO₂Less than 50% by mass of Al₂O₃The mass fraction is less than 13 percent.

The tungsten tailings adopted by the invention have an average particle size of 25 mu m after ball milling, which is similar to the particle size of the finely ground quartz sand, and the particles can be uniformly dispersed in the slurry. The particles with smaller particle size have larger specific surface area, so that the hydration reaction process among materials can be improved in the steam-pressing process, and the crystallinity is greatly improved. On a microscopic level, ball milling can promote the crystal lattice of the particles to generate distortion, even cut off Si-O bonds and Al-O bonds on the surface, so as to generate atom groups with higher activity, improve the instability of the structure, increase the reaction activity of the autoclave and improve the speed of hydration reaction, thereby achieving the purpose of improving the strength of the autoclave and concrete products thereof.

The invention adopts the water glass which can play a stabilizing role to the slurry, not only can fill air pores and capillary pores, but also can improve the integral pore structure of the autoclaved aerated concrete, and the silicon in the water glass can be further mixed with Ca (OH) in the slurry in the process of autoclaving₂The reaction generates hydration products with high Si/Ca content, and the strength of the product is further improved.

The tungsten tailings used in the invention are SiO₂Lower content, but Al₂O₃The content of the quartz sand is about 10 percent higher than that of the common quartz sand. XRD results show that under the conditions of low silicon content and high aluminum content, Tobermorite (Tobermorite) and aluminum-substituted Toberlite are also generated in the autoclaving process, so that the strength of the product is further improved.

The dihydrate gypsum adopted by the invention can participate in the hydration reaction of cement, and the setting time of the cement is adjusted. Meanwhile, the slaking reaction speed of lime can be inhibited, the stability of slurry pouring is improved, and the later period contractibility of products is obviously improved.

The aluminum potassium sulfate dodecahydrate adopted by the invention can release part of carbon dioxide gas in an alkaline environment to achieve the effect of auxiliary gas generation. At the same time, it can release AL in the aqueous phase³⁺Metal ions to form AL (OH)₃The colloid improves the coupling property of the product embryo at the early stage and achieves the effect of stabilizing the volume change.

The sodium dodecyl sulfate adopted by the invention can partially replace aluminum powder in the autoclaved aerated concrete to serve as an auxiliary gas generation means, is easy to dissolve in water, has good dispersion capacity, and can obviously improve the dispersion of gas in slurry. Because the surface of the bubble is electronegative, the bubble emulsifying device has an emulsifying effect, so that bubbles are not easy to annihilate and break, and the purposes of stabilizing the bubble structure and improving the strength of an embryo body are achieved.

As an optional implementation mode, the quicklime has the digestion speed of more than 10min, the digestion temperature of more than 50 ℃ and the calcium oxide content of more than 60 percent.

As an alternative embodiment, the cementitious material comprises either or both of portland cement and sulphoaluminate cement.

As an optional embodiment, the water reducing agent is any one or two of a naphthalene water reducing agent and a polycarboxylic acid water reducing agent.

As an alternative embodiment, SiO in the quartz sand₂Content > 70%, SiO₂The particle size is 15-75 μm.

As an optional embodiment, the dihydrate gypsum is any one or more of natural gypsum, desulfurized gypsum and phosphogypsum.

In an alternative embodiment, the water glass is a sodium silicate solution, the modulus of the sodium silicate solution is > 1, and the mass fraction of the sodium silicate solution is > 20%.

As an optional embodiment, the aluminum potassium sulfate dodecahydrate contains more than 90% of effective components, and the pH value is 2.5-6.5.

As an alternative embodiment, the sodium lauryl sulfate has an active content > 30%, a petroleum ether solubles greater than 1%, and an inorganic salt content less than 10%.

The invention provides an implementation step for preparing autoclaved aerated concrete by using tungsten tailings, which comprises the following steps: firstly, SiO is firstly₂Less than 50% by mass, Al₂O₃Dehydrating and drying the tungsten tailings with the mass fraction of less than 13%, grinding by a ball milling process, and sieving to obtain a part with the particle size of less than 0.075 mm; then, tungsten tailings are used for replacing quartz sand in autoclaved aerated concrete ingredients, the replacement rate is 0-100% (mass fraction), then, a cementing material, dihydrate gypsum, quicklime and water are added, aluminum powder is added after high-speed stirring, the mixture is poured into a mold after being uniformly stirred again, and then, the mixture is moved into a static curing chamber to be pre-cured at the temperature higher than 40 ℃.

In the process of pre-curing, the added aluminum powder can generate chemical reaction to generate hydrogen under the alkaline heating condition, the poured slurry starts to foam and gradually rises and expands, and the slurry starts to harden along with the proceeding of the hydration reaction of the cementing material and keeps the blank state after the gas generation. And after forming, the blank is demoulded and cut as required, and then is moved into an autoclave for autoclave curing and forming.

Example 1

1.1 raw material ratio

The weight percentage of each component of example 1 is shown in the following table.

1.2 preparation steps

Weighing the tungsten tailings, quartz sand, quicklime, portland cement, dihydrate gypsum and sodium dodecyl sulfate which are dried after ball milling according to the mass ratio, wherein the total mass is 40 kg. Weighing, fully mixing, injecting into a stirrer, adding water with the water-material ratio of 0.61, and stirring at a high speed of 350r/min for 5 minutes. Then adding a water reducing agent and then adding aluminum powder paste; then stirring at high speed for 1min, injecting into a grinding tool, and controlling the pouring temperature to be about 35 ℃. And then moving into a pre-curing chamber, setting the ambient temperature to be 70 ℃, standing for 8 hours, and then moving into an autoclave. And (3) heating to the temperature of 50-65 ℃ for 30min under the steam pressure condition, heating to 200 ℃, preserving heat for 5 hours, naturally cooling, taking out from the kettle, and removing the mold to finish the sample preparation. 3 cubic test pieces of 100mm multiplied by 100mm are molded from each group of autoclaved aerated concrete, and the compressive strength of the test pieces is tested. The compression strength of the reference test piece without the water reducing agent after being taken out of the kettle and dried is 2.1 MPa; the compressive strength of a sample which uses the water reducing agent and the sodium dodecyl sulfate and replaces quartz sand with tungsten tailings is 3.6MPa after being taken out of a kettle, and is improved by 71.4 percent compared with that of a reference test piece.

Example 2

2.1 raw material ratio

The specific data of the weight percentages of the components of example 2 are shown in the following table.

2.2 preparation steps

Weighing the tungsten tailings, quartz sand, quicklime, portland cement, dihydrate gypsum and aluminum potassium sulfate which are dried after ball milling according to the mass ratio, wherein the total mass is 40 kg. Weighing, mixing thoroughly, injecting into a stirrer, adding water at a water-material ratio of 0.63, and stirring at high speed for 5 minutes. Then adding a water reducing agent, adding water glass, and finally adding aluminum powder paste; then stirring at high speed for 1min, injecting into a grinding tool, and controlling the pouring temperature to be about 35 ℃. And then moving into a pre-curing chamber, setting the ambient temperature to be 70 ℃, standing for 8 hours, and then moving into an autoclave. And (3) carrying out autoclaving, namely heating to 180 ℃, preserving heat for 5 hours, then naturally cooling, taking out of the kettle, and removing a mold to complete sample preparation. 3 cubic test pieces of 100mm multiplied by 100mm are molded from each group of autoclaved aerated concrete, and the compressive strength of the test pieces is tested. Taking the reference test piece without adding the water reducing agent and the water glass out of the kettle, and drying to obtain a compression strength of 1.9 MPa; the compressive strength of a sample which uses the water reducing agent and the water glass and replaces quartz sand with tungsten tailings is 3.4MPa after being taken out of a kettle, and is improved by 78.9 percent compared with that of a reference test piece.

Example 3

3.1 raw material ratio

The specific data of the weight percentages of the components of example 3 are shown in the following table.

3.2 preparation steps

The specific preparation steps are the same as those in example 1,

taking the reference test piece without adding the water reducing agent and the water glass out of the kettle, and drying to obtain the test piece with the compressive strength of 1.9 MPa; the compressive strength of a sample which uses the water reducing agent and the water glass and replaces quartz sand with tungsten tailings is 3.8MPa after being taken out of a kettle, and is improved by 100 percent compared with that of a reference test piece.

Example 4

4.1 raw material ratio

The specific data of the weight percentages of the components of example 4 are shown in the following table.

4.2 preparation step

The specific preparation steps are the same as those in example 1,

taking the reference test piece without adding the water reducing agent and the water glass out of the kettle, and drying to obtain the test piece with the compressive strength of 1.9 MPa; the compressive strength of a sample which uses the water reducing agent and the water glass and replaces quartz sand with tungsten tailings is 3.2MPa after being taken out of a kettle, and is improved by 68.42 percent compared with that of a reference test piece.

Example 5

5.1 proportioning of raw materials

The specific data of the weight percentages of the components of example 5 are shown in the following table.

5.2 preparation step

The specific preparation steps are the same as those in example 1,

taking the reference test piece without adding the water reducing agent and the water glass out of the kettle, and drying to obtain a compression strength of 1.9 MPa; the compressive strength of a sample which uses the water reducing agent and the water glass and replaces quartz sand with tungsten tailings is 3.6MPa after being taken out of a kettle, and is improved by 100 percent compared with that of a reference test piece.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. The tungsten tailing autoclaved aerated concrete is characterized by comprising the following components in percentage by mass: 50-75% of sand material, 5-25% of quicklime, 10-30% of cementing material, 0.1-2% of water reducing agent, 1-5% of dihydrate gypsum, 1.1-5% of additive, 0.1-2% of aluminum potassium sulfate dodecahydrate and 0.1-1% of aluminum powder paste, wherein the additive is any one or two of sodium dodecyl sulfate and water glass;

2. The tungsten tailing autoclaved aerated concrete according to claim 1, which is characterized in that: the slaking speed of the quicklime is more than 10min, the slaking temperature is more than 50 ℃, and the content of calcium oxide is more than 60%.

3. The tungsten tailing autoclaved aerated concrete according to claim 1, which is characterized in that: the cementing material comprises any one or two of Portland cement and sulphoaluminate cement.

4. The tungsten tailing autoclaved aerated concrete according to claim 1, which is characterized in that: the water reducing agent is one or two of a naphthalene water reducing agent and a polycarboxylic acid water reducing agent.

5. The tungsten tailing autoclaved aerated concrete according to claim 1, which is characterized in that: SiO in the quartz sand₂Content > 70%, SiO₂The particle size is 15-75 μm.

6. The tungsten tailing autoclaved aerated concrete according to claim 1, which is characterized in that: the dihydrate gypsum is any one or more of natural gypsum, desulfurized gypsum and phosphogypsum.

7. The tungsten tailing autoclaved aerated concrete according to claim 1, which is characterized in that: the water glass is a sodium silicate solution, the modulus of the sodium silicate solution is more than 1, and the mass fraction of the sodium silicate solution is more than 20%.

8. The tungsten tailing autoclaved aerated concrete according to claim 1, which is characterized in that: the aluminum potassium sulfate dodecahydrate contains more than 90% of effective components, and the pH value is 2.5-6.5.

9. The tungsten tailing autoclaved aerated concrete according to claim 1, which is characterized in that: the content of active substances of the sodium dodecyl sulfate is more than 30 percent, the content of petroleum ether soluble substances is more than 1 percent, and the content of inorganic salts is less than 10 percent.

10. The preparation method of the tungsten tailing autoclaved aerated concrete according to claim 1, which is characterized by comprising the following preparation steps: