CN108675799B - Red mud permeable brick and preparation method thereof - Google Patents

Abstract

The embodiment of the invention relates to a red mud permeable brick and a preparation method thereof, relates to the technical field of red mud permeable bricks, and mainly aims to improve the durability of the red mud permeable brick. The main technical scheme adopted is as follows: the preparation method of the red mud permeable brick comprises the following steps: preparing red mud particles by granulating red mud powder; forming glass powder on the outer surface of the red mud particles to form red mud glass cores; and forming and firing the red mud permeable brick by using the red mud glass core and the pore-forming agent. According to the red mud permeable brick provided by the embodiment of the invention, the permeable brick body is formed by the red mud glass core, the red mud glass core comprises the red mud particles and the glass layer coated on the outer surface of the red mud particles, and the glass layer effectively coats the red mud particles so that the red mud particles are not easy to return alkali; in addition, the strength of the glass layer is far higher than that of the red mud particles, so that the overall high pressure resistance of the red mud permeable brick can be improved, and the compressive strength can reach 42MPa through tests, so that the durability of the red mud permeable brick is improved compared with the prior art.

Description

Red mud permeable brick and preparation method thereof

Technical Field

The embodiment of the invention relates to the technical field of red mud permeable bricks, in particular to a red mud permeable brick and a preparation method thereof.

Background

China is a large country for producing alumina, and the comprehensive utilization rate of red mud in China is only 4 percent at present. With the annual increase of alumina yield and gradual reduction of bauxite grade in China, the stacking amount of red mud is continuously increased. At present, the comprehensive utilization of the red mud still belongs to a worldwide problem, and the red mud is mainly treated by a stockpiling and covering agent internationally. The alkali content in the red mud is very high, so the disposal mode can bring unpredictable harm to peripheral animals and plants, underground water and the like. The comprehensive utilization work of the red mud in China has been paid high attention in all aspects in recent years, and research work of comprehensive utilization across subjects and multiple fields is carried out.

The red mud permeable brick is a novel product taking red mud as a raw material, can be applied to paving roads and squares, and can enable part of rainfall to permeate into the ground due to the porous structure inside the red mud permeable brick. The red mud permeable brick is mainly divided into three main types: the red mud-based water permeable brick has the problems of low strength and the like in the baking-free type, the low-temperature calcination type (350 ℃) and the high-temperature sintering type (1100 ℃ -1200 ℃).

Disclosure of Invention

In view of this, the embodiment of the invention provides a red mud permeable brick and a preparation method thereof, and mainly aims to improve the durability of the red mud permeable brick.

In order to achieve the above purpose, the embodiments of the present invention mainly provide the following technical solutions:

on the one hand, the embodiment of the invention provides a preparation method of a red mud permeable brick, which comprises the following steps:

preparing red mud particles by granulating red mud powder;

forming glass powder on the outer surface of the red mud particles to form red mud glass cores;

and forming and firing the red mud permeable brick by using the red mud glass core and the pore-forming agent.

The purpose of the embodiments of the present invention and the technical problems solved thereby can be further realized by the following technical measures.

Optionally, the method for preparing the red mud permeable brick, wherein the red mud permeable brick is formed and fired by the red mud glass core and the pore-forming agent, comprises the following steps:

forming pore-forming agents with M grades of particle sizes on the outer surface of the red mud glass core respectively to form M grades of mixture corresponding to the pore-forming agents with M grades of particle sizes one by one, wherein the sizes of the M grades of particle sizes are increased in sequence, and M is a positive integer greater than or equal to 2;

sequentially stacking the M grades of mixed materials in a permeable brick die, and carrying out extrusion forming on M layers of mixed materials in the permeable brick die to form M layers of permeable brick blanks;

and firing the red mud permeable brick from the M layers of permeable brick blanks.

Optionally, in the method for preparing the red mud water permeable brick, firing the red mud water permeable brick blank for the M layers of water permeable brick blanks includes:

drying the M layers of permeable brick blanks for not less than 12 hours at the temperature of between 50 and 150 ℃;

and (3) raising the furnace temperature to 1000-1250 ℃ in stages at a temperature raising rate of 30-180 ℃/h for the dried M-layer water permeable brick blank, preserving the temperature for 2-6 h, and then lowering the temperature to room temperature at a rate of 120-300 ℃/h to prepare the red mud water permeable brick.

Optionally, the preparation method of the red mud water permeable brick, wherein the forming of the glass powder on the outer surface of the red mud particles to form the red mud glass core, comprises:

and spraying glass powder on the outer surfaces of the red mud particles to form red mud glass cores.

Optionally, the preparation method of the red mud permeable brick, in which red mud particles are prepared by granulating red mud powder, includes:

preparing red mud particles to be screened by adopting red mud powder with the particle size of 10-30 mu m and adopting a centrifugal spray granulation process;

screening the red mud particles to be screened to obtain the red mud particles with the particle size of 50-100 mu m.

Optionally, in the preparation method of the red mud water permeable brick, the particle size of the glass powder is 1 μm to 10 μm.

On the other hand, the embodiment of the invention provides a red mud permeable brick, which comprises:

the red mud glass core comprises red mud particles and a glass layer wrapping the outer surfaces of the red mud particles.

The purpose of the embodiments of the present invention and the technical problems solved thereby can be further realized by the following technical measures.

Optionally, the red mud water permeable brick body comprises M water permeable brick layers stacked in sequence; the diameter of the permeable holes of the M permeable brick layers is increased in sequence.

Optionally, in the red mud permeable brick, the M permeable brick layers sequentially include a first permeable brick layer, a second permeable brick layer, and a third permeable brick layer,

the diameter of the water permeable holes of the first water permeable brick layer is 0.1-1 mu m;

the diameter of the water permeable holes of the second water permeable brick layer is 2-10 mu m;

the diameter of the water permeable holes of the third water permeable brick layer is 11-100 mu m.

Optionally, the red mud permeable brick comprises red mud particles accounting for 60-90% of the weight of the permeable brick body.

By the technical scheme, the red mud permeable brick and the preparation method thereof provided by the technical scheme of the invention at least have the following advantages:

according to the red mud permeable brick provided by the embodiment of the invention, the permeable brick body is formed by the red mud glass core, the red mud glass core comprises the red mud particles and the glass layer coated on the outer surface of the red mud particles, and the glass layer effectively coats the red mud particles so that the red mud particles are not easy to return alkali; in addition, the strength of the glass layer is far higher than that of the red mud particles, so that the overall high pressure resistance of the red mud permeable brick can be improved, and the compressive strength can reach 42MPa through tests, so that the durability of the red mud permeable brick is improved compared with the prior art.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the embodiments of the present invention more clear and clear, and to implement the technical solutions according to the contents of the description, the following detailed description is made with reference to the preferred embodiments of the present invention and accompanying drawings.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

fig. 1 is a schematic structural diagram of a red mud permeable brick provided by an embodiment of the invention.

Detailed Description

In order to further illustrate the technical means and effects adopted to achieve the purpose of the predetermined invention embodiments, the red mud permeable brick and the preparation method thereof according to the embodiments of the present invention, the specific implementation, structure, characteristics and effects thereof are described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "an embodiment" refers to not necessarily the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

The preparation method of the red mud permeable brick provided by one embodiment of the invention comprises the following steps:

preparing red mud particles by granulating red mud powder;

for example, the red mud particles can be prepared by a wet or dry ball milling process, and the particle size of the red mud particles can be 10-30 μm. The red mud powder can be the polluting waste residue discharged when extracting aluminum oxide in the aluminum production industry.

Forming glass powder on the outer surface of the red mud particles to form red mud glass cores;

for example, glass powder is sprayed (atomized or directly sprayed) on the outer surface of the red mud particles; in some embodiments, the glass frit is borosilicate glass, wherein the mass of each substance in total weight is: s iO₂50% -60%; b is₂O₃5-10%; al (Al)₂O₃10 to 20 percent; CaO accounts for 10 to 20 percent; and alkali metals. In addition, other substances can be added in the amount of 1 to 5 percent.

And forming and firing the red mud permeable brick by using the red mud glass core and the pore-forming agent.

For example, the red mud permeable brick formed and fired by the red mud glass core and the pore-forming agent comprises:

forming a pore-forming agent on the outer surface of the red mud glass core to form a mixture;

wherein the pore-forming agent can be carbon powder, sawdust, starch, walnut shell, polyvinyl alcohol, methyl methacrylate, polyvinyl chloride or polystyrene, etc.

Laying the mixture in a permeable brick die, and carrying out extrusion forming on the mixture in the permeable brick die to form a permeable brick blank;

firing the red mud water permeable brick from the water permeable brick blank specifically comprises the following steps:

drying the permeable brick blank for not less than 12 hours at the temperature of 50-150 ℃;

and (3) raising the furnace temperature to 1000-1250 ℃ in stages at a temperature raising rate of 30-180 ℃/h for the dried water permeable brick blank, preserving the temperature for 2-6 h, and then lowering the temperature to room temperature at a rate of 120-300 ℃/h to prepare the red mud water permeable brick.

The pore-forming agent accounts for 15-35% of the total weight of the pore-forming agent and the red mud glass core. The grain diameter of the pore-forming agent is controlled within the range of 1-1000 μm.

The red mud permeable brick can be prepared by the red mud permeable brick preparation method provided by the embodiment of the invention, the permeable brick body is formed by the red mud glass core, the red mud glass core comprises red mud particles and a glass layer coated on the outer surface of the red mud particles, and the red mud particles are efficiently coated by the glass layer so as to be difficult to return alkali; in addition, the strength of the glass layer is far higher than that of the red mud particles, so that the overall high pressure resistance of the red mud permeable brick can be improved, and the compressive strength can reach 42MPa through tests, so that the durability of the red mud permeable brick is improved compared with the prior art. According to the embodiment of the invention, the red mud particles can be prepared by centrifugal spray granulation, and then are subjected to centrifugal granulation and atomization spraying to form the red mud particles, the red mud particles can be effectively and uniformly coated when the weight percentage of the glass powder is 10%, and the related characteristics of the final product can meet the industrial standard requirements of the water permeable brick.

In the concrete implementation, red mud particles are prepared by granulating red mud powder; the method comprises the following steps:

preparing red mud particles to be screened by adopting red mud powder with the particle size of 10-30 mu m and adopting a centrifugal spray granulation process;

screening the red mud particles to be screened to obtain the red mud particles with the particle size of 50-100 mu m.

Correspondingly, the particle size of the glass powder can be 1-10 μm.

Through the method, the red mud permeable brick can be prepared, the pore size inside the red mud permeable brick is uniform, in other embodiments provided by the invention, the red mud permeable brick with different layered pore sizes can also be prepared, and the red mud permeable brick is formed and fired by adopting the red mud glass core and the pore-forming agent, and comprises the following steps:

forming pore-forming agents with M grades of particle sizes on the outer surface of the red mud glass core respectively to form M grades of mixture corresponding to the pore-forming agents with M grades of particle sizes one by one, wherein the sizes of the M grades of particle sizes are increased in sequence, and M is a positive integer greater than or equal to 2;

sequentially stacking the M grades of mixed materials in a permeable brick die, and carrying out extrusion forming on M layers of mixed materials in the permeable brick die to form M layers of permeable brick blanks; the extrusion pressure can be 50 MPa-200 MPa.

And firing the red mud permeable brick from the M layers of permeable brick blanks.

The thickness of the M layers of permeable brick blanks can be gradually reduced. Specifically, firing red mud water permeable brick to M layer water permeable brick blank includes:

drying the M layers of permeable brick blanks for not less than 12 hours at the temperature of between 50 and 150 ℃;

and (3) raising the furnace temperature to 1000-1250 ℃ in stages at a temperature raising rate of 30-180 ℃/h for the dried M-layer water permeable brick blank, preserving the temperature for 2-6 h, and then lowering the temperature to room temperature at a rate of 120-300 ℃/h to prepare the red mud water permeable brick.

The value of M is determined according to the requirement, taking M equal to 4 as an example, the pore-forming agents with M grades of particle sizes comprise a first grade pore-forming agent, a second grade pore-forming agent, a third grade pore-forming agent and a fourth grade pore-forming agent. The grain diameter of the first-grade pore-forming agent is controlled to be 1-10 mu m, the grain diameter of the second-grade pore-forming agent is controlled to be 11-100 mu m, the grain diameter of the third-grade pore-forming agent is controlled to be 101-500 mu m, and the grain diameter of the fourth-grade pore-forming agent is controlled to be 501-1000 mu m. The thickness ratio of the 4 layers of permeable brick blanks is 4:3:2: 1.

Fig. 1 shows an embodiment of a red mud permeable brick provided by the present invention, and referring to fig. 1, the red mud permeable brick provided by an embodiment of the present invention includes: the red mud glass core comprises red mud particles and a glass layer wrapping the outer surfaces of the red mud particles.

According to the red mud permeable brick provided by the embodiment of the invention, the permeable brick body is formed by the red mud glass core, the red mud glass core comprises the red mud particles and the glass layer coated on the outer surface of the red mud particles, and the glass layer effectively coats the red mud particles so that the red mud particles are not easy to return alkali; in addition, the strength of the glass layer is far higher than that of the red mud particles, so that the overall high pressure resistance of the red mud permeable brick can be improved, and the compressive strength can reach 42MPa through tests, so that the durability of the red mud permeable brick is improved compared with the prior art.

The water permeable brick body comprises M water permeable brick layers which are sequentially stacked; the diameter of the permeable holes of the M permeable brick layers is increased in sequence. For example, as shown in fig. 1, the M water permeable brick layers sequentially include a first water permeable brick layer 10, a second water permeable brick layer 20, and a third water permeable brick layer 30, and the pore diameter of the water permeable pores of the first water permeable brick layer 10 is 0.1 μ M to 1 μ M; the diameter of the water permeable holes of the second water permeable brick layer 20 is 2-10 μm; the pore diameter of the permeable pores of the third permeable brick layer 30 is 11-100 μm.

The red mud particles account for 60-90% of the weight of the water permeable brick body.

The technical scheme of the embodiment of the invention at least has the following advantages:

the red mud permeable brick is not easy to return alkali, high in strength and good in freezing resistance, and through the design of a red mud glass core structure and high-temperature firing, the red mud particles are efficiently coated by glass powder, so that the problem that the red mud permeable brick is easy to return alkali is solved; the intrinsic strength of the selected glass powder is far higher than that of the red mud, and the realization of high compressive strength can be effectively guaranteed through the red mud glass core structure design, and the highest compressive strength of the red mud permeable brick prepared by the invention can reach 42MPa through tests; through the ion granulation and atomization spraying processes, the red mud particles/glass powder/pore-forming agent can be uniformly mixed, and the uniformity and connectivity of the final pore structure of the red mud permeable brick are ensured, so that the internal stress is relatively uniform in the frost resistance test, and the frost resistance of the product is effectively improved under the high-strength support of the permeable brick.

Secondly, the red mud permeable brick is not easy to block holes, a layered gradient hole structure with micropores of 0.1-1 mu m, micropores of 2-10 mu m, coarse holes of 11-100 mu m and the like is formed through structural design, the pore size distribution of a surface microporous layer is controlled within the range of 0.1-1 mu m, and the conventional impurities and dust can be better prevented from entering; the pore size distribution of the fine pore layer and the coarse pore layer is controlled within the range of 2-10 μm and 11-100 μm respectively, so that the high water permeability of the water permeable brick can be effectively ensured.

Thirdly, the comprehensive utilization rate of the red mud is high, the red mud can be effectively and uniformly coated when the weight percentage of the glass powder is 10% by combining a secondary granulation process (preparing red mud cores by centrifugal spray granulation, and forming a core-shell structure by centrifugal granulation and atomization spraying) through the core-shell structure design of the red mud particles/the glass powder/the pore-forming agent, and the related characteristics of the final product can meet the industrial standard requirements of the water permeable brick.

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

It will be appreciated that the relevant features of the devices described above may be referred to one another. In addition, "first", "second", and the like in the above embodiments are for distinguishing the embodiments, and do not represent merits of the embodiments.

In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed apparatus should not be construed to reflect the intent as follows: that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Those skilled in the art will appreciate that the components of the apparatus of the embodiments may be adapted and arranged in one or more arrangements different from the embodiments. The components of the embodiments may be combined into one component and, in addition, they may be divided into a plurality of sub-components. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the components of any apparatus so disclosed, may be combined in any combination, except combinations where at least some of such features are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination. The various component embodiments of the present invention may be implemented in hardware, or in a combination thereof.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or components not listed in a claim. The word "a" or "an" preceding a component or element does not exclude the presence of a plurality of such components or elements. The invention may be implemented by means of an apparatus comprising several distinct elements. In the claims enumerating several means, several of these means may be embodied by one and the same item. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any simple modification, equivalent change and modification made to the above embodiment according to the technical spirit of the present invention are still within the scope of the technical solution of the present invention.

Claims (7)

1. The preparation method of the red mud permeable brick is characterized by comprising the following steps:

preparing red mud particles by granulating red mud powder; the preparation of the red mud particles by adopting the red mud powder granulation comprises the following steps: preparing red mud particles to be screened by adopting red mud powder with the particle size of 10-30 microns and adopting a centrifugal spray granulation process, and screening the red mud particles to be screened to obtain red mud particles with the particle size of 50-100 microns;

forming glass powder on the outer surface of the red mud particles to form red mud glass cores; the forming of the glass powder on the outer surface of the red mud particles to form the red mud glass core comprises the following steps: spraying glass powder on the outer surface of the red mud particles to form red mud glass cores, wherein the particle size of the glass powder is 1-10 mu m;

and forming and firing the red mud permeable brick by using the red mud glass core and the pore-forming agent.

2. The production method according to claim 1,

the red mud permeable brick is formed and fired by the red mud glass core and the pore-forming agent, and comprises the following components:

forming pore-forming agents with M grades of particle sizes on the outer surface of the red mud glass core respectively to form M grades of mixture corresponding to the pore-forming agents with M grades of particle sizes one by one, wherein the sizes of the M grades of particle sizes are increased in sequence, and M is a positive integer greater than or equal to 2;

sequentially stacking the M grades of mixed materials in a permeable brick die, and carrying out extrusion forming on M layers of mixed materials in the permeable brick die to form M layers of permeable brick blanks;

and firing the red mud permeable brick from the M layers of permeable brick blanks.

3. The production method according to claim 2,

firing the red mud water permeable brick for the M layers of water permeable brick blanks comprises the following steps:

drying the M layers of permeable brick blanks for not less than 12 hours at the temperature of between 50 and 150 ℃;

and (3) raising the furnace temperature to 1000-1250 ℃ in stages at a temperature raising rate of 30-180 ℃/h for the dried M-layer water permeable brick blank, preserving the temperature for 2-6 h, and then lowering the temperature to room temperature at a rate of 120-300 ℃/h to prepare the red mud water permeable brick.

4. The red mud permeable brick prepared by the red mud permeable brick preparation method according to any one of claims 1 to 3, which is characterized by comprising the following steps:

the red mud glass core comprises red mud particles and a glass layer wrapping the outer surfaces of the red mud particles.

5. The red mud permeable brick according to claim 4,

the water permeable brick body comprises M water permeable brick layers which are sequentially stacked; the diameter of the permeable holes of the M permeable brick layers is increased in sequence.

6. The red mud permeable brick according to claim 5,

the M permeable brick layers sequentially comprise a first permeable brick layer, a second permeable brick layer and a third permeable brick layer,

the diameter of the water permeable holes of the first water permeable brick layer is 0.1-1 mu m;

the diameter of the water permeable holes of the second water permeable brick layer is 2-10 mu m;

the diameter of the water permeable holes of the third water permeable brick layer is 11-100 mu m.

7. The red mud permeable brick according to claim 4,

the red mud particles account for 60-90% of the weight of the water permeable brick body.

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