CN107352928B - Red mud-fly ash high-strength heat-insulation building block based on alkali excitation and preparation method thereof - Google Patents

Abstract

The invention discloses a red mud-fly ash high-strength heat-insulation building block based on alkali excitation, which takes industrial waste fly ash and red mud as main raw materials, cement and quicklime as auxiliary materials, and fly ash pottery sand or shale pottery sand as a heat-insulation material. The high-strength red mud brick is prepared from 18-40% of red mud, 18-30% of fly ash, 25-40% of ceramic sand, 3-8% of cement, 3-10% of lime, 1-3% of straw fiber, 0.5-2% of early strength agent, 10-15% of water content and 8-36h of aging by adopting 40MPa pressure for molding; the material is prepared by the processes of drying, grinding, weighing, mixing and pressurizing molding, standard maintenance and natural maintenance; the invention has the advantages of simple forming process, normal-temperature rapid reaction and solidification, no sintering and no autoclaving, and the product has high compressive strength, strong dry shrinkage resistance, good anti-permeability performance and no scumming phenomenon after long-term storage. The invention can utilize industrial waste in large quantity, save energy and resources, and has low cost and low energy consumption.

Description

Red mud-fly ash high-strength heat-insulation building block based on alkali excitation and preparation method thereof

Technical Field

The invention belongs to the field of building material wall building blocks, and particularly relates to a red mud-fly ash high-strength heat-insulation building block based on alkali excitation and a preparation method thereof.

Background

The fly ash is a large amount of industrial waste residue discharged by thermal power generation, about 2 hundred million tons of fly ash are discharged in China every year, and the annual cost for directly treating the fly ash in China reaches billions of yuan. With the increasingly intensive research on fly ash, people are workingIt is gradually recognized that fly ash is not an industrial waste residue, but an available resource. The fly ash is mainly used for backfilling, road building and the like, can be used for building materials to replace a small amount of cement, only 20% of the fly ash is used for building materials, and compared with other industrial waste residues, the utilization rate and the utilization level of the fly ash are not high. The red mud is insoluble residue waste mud in the production process of extracting alumina from bauxite, 1-2 tons of red mud is discharged when 1 ton of alumina is produced, and the domestic red mud output exceeds 350 million tons per year. At present, red mud is transported to a yard by alumina factories at home and abroad, and is stockpiled by a damming wet method, and a large amount of waste alkali liquor is easy to permeate into nearby soil by the method to cause soil alkalization. On the other hand, clay bricks play an important role in production and life as widely used building materials. Although various novel building materials are continuously emerged in recent years, the clay brick is still the main wall material in China at present. The development of clay bricks is largely at the cost of destroying the arable land, consuming non-renewable energy and polluting the environment. It is estimated that, in the last sixty years, 17 million hectares of cultivated land are destroyed by firing clay bricks, 7000 million tons of coal are consumed annually by firing clay bricks, and SO is accompanied₂And CO₂And the like.

Disclosure of Invention

Aiming at the defects of the prior art, the invention mainly aims to provide the alkali-activated red mud-fly ash high-strength heat-insulation building block and the preparation method thereof, and the alkali-activated red mud-fly ash high-strength heat-insulation building block has the advantages of simple forming process, normal-temperature rapid reaction and solidification, no sintering and no autoclaving, and the product has high compressive strength, strong dry shrinkage resistance, good anti-permeability performance and no scumming phenomenon after long-term storage; but also can utilize industrial waste in a large quantity, save energy and resources, and has low cost and low energy consumption.

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

the red mud-fly ash high-strength heat-insulating building block based on alkali excitation uses industrial waste fly ash and red mud as main raw materials, cement and quicklime as auxiliary materials, and fly ash pottery sand or shale pottery sand as a heat-insulating material. The weight percentage composition is as follows: 18-40% of red mud, 18-30% of fly ash, 25-40% of ceramic sand, 3-8% of cement, 3-10% of lime, 1-3% of straw fiber, 0.5-2% of early strength agent and 10-15% of water content; the material is prepared by the processes of drying, grinding, weighing, mixing ingredients, 40MPa pressure forming, standard curing and natural curing; the specific method comprises the following steps:

(1) and a drying process: drying the red mud, the fly ash and the ceramic sand by using a dryer to remove free moisture in the red mud, the fly ash and the ceramic sand;

(2) and the grinding process comprises the following steps: the mud, the fly ash and the pottery sand are weighed and mixed according to the raw material formula, and the three mixtures are put into a ball mill for grinding until the specific surface area is more than 600m²Per kg; the mixture ratio is 18-40% of red mud, 18-30% of fly ash and 25-40% of ceramic sand;

(3) and raw material proportioning and aging: 18-40% of red mud, 18-30% of fly ash, 25-40% of ceramic sand, 3-8% of cement, 3-10% of lime, 1-3% of straw fiber, 0.5-2% of early strength agent and 10-15% of water in the total mass ratio; putting all the raw materials into a stirrer, fully stirring and mixing, and aging for 8-36h at the room temperature of 10-15 ℃;

(4) and pressure forming: pouring the mixture into a mold, and molding under the action of a 40MPa press;

(5) and naturally maintaining: and taking out the pressed building block, and conveying the building block to a maintenance site for natural maintenance.

Wherein, the red mud is industrial waste residue generated by extracting alumina in the aluminum production industry, and is dried and crushed until the particle size is less than 0.15 mm.

The fly ash is collected by crushing, grinding, high-fineness grinding and high-temperature or combustion treatment of coal gangue.

The lime is quicklime.

The cement is ordinary portland cement.

The pottery sand is fly ash pottery sand or shale pottery sand.

The early strength agent is a compound early strength agent of 20 percent of ferric chloride, 40 percent of sodium carbonate and 40 percent of triethanolamine.

According to the characteristics that the sintering process red mud has strong basicity, fine particle size and developed pores, the sintering process red mud is used as an alkali activator and fly ash to produce the novel high-strength heat-insulation building block material, so that land and energy are saved, a large amount of industrial wastes such as the red mud and the fly ash are consumed, and environmental pollution is reduced; and simultaneously overcomes the dilemma faced by firing clay bricks.

The invention has the following advantages:

1. the fly ash pottery sand or shale pottery sand is used as a heat insulation material, so that the heat conductivity of the building block is reduced, and the heat insulation performance of the heat insulation brick is obviously improved.

2. The early strength is high, and the later strength can reach the national standard.

3. Based on the red mud-fly ash excited by alkali, active particles are greatly reduced, and the product is more durable and more environment-friendly.

4. After the insulating brick is formed by each construction process, the final strength grade is 26MPa-38MPa, and the insulating brick has the characteristic of high strength.

5. The invention has the advantages of simple forming process, normal-temperature rapid reaction and solidification, no sintering and no autoclaving, and the product has high compressive strength, strong dry shrinkage resistance, good anti-permeability performance and no scumming phenomenon after long-term storage.

6. The method has the advantages of large utilization of industrial waste, energy and resource saving, low cost, low energy consumption, and obvious economic, environmental and social benefits.

The invention has reasonable design, takes the industrial waste fly ash and red mud as main raw materials, cement and quicklime as auxiliary materials, and fly ash pottery sand or shale pottery sand as a heat-insulating material, greatly utilizes the industrial waste, saves energy, protects cultivated land, reduces pollution, improves building function and has great social and economic benefits.

Drawings

FIG. 1 shows the process flow of the preparation method of the present invention.

Detailed Description

The following provides a detailed description of specific embodiments of the present invention.

Example 1

Mixing 250g of red mud, 250g of fly ash pottery sand, 50g of cement, 50g of lime, 20g of straw fiber, 10g of early strength agent and 120g of water (wherein the red mud, the fly ash and the ceramsite are dehydrated and dried, and are mixed with the early strength agent after being ball-milled), fully stirring, aging for 24 hours at the room temperature of 10-15 ℃, pouring the mixture into a mold, molding under the action of a 40MPa press machine, taking out the press-molded building block, and conveying the building block to a curing site for natural curing.

Example 2

200g of red mud, 250g of fly ash, 300g of shale ceramic sand, 40g of cement, 70g of lime, 15g of straw fiber, 8g of early strength water reducing agent and 110g of water are mixed (wherein the red mud, the fly ash and the ceramsite are dehydrated and dried, and are mixed with water and the early strength agent after ball milling), the mixture is fully stirred and aged for 24 hours at the room temperature of 10-15 ℃, the mixture is poured into a mold and molded under the action of a 40MPa press machine, and then the molded building block is taken out and conveyed to a curing site for natural curing.

Example 3

Mixing 300g of red mud, 200g of fly ash, 300g of shale ceramic sand, 60g of cement, 50g of lime, 20g of straw fiber, 13g of early strength agent and 125g of water (wherein the red mud, the fly ash and the ceramsite are dehydrated and dried, and are mixed with water and an early strength water reducing agent after ball milling), fully stirring, aging for 24 hours at the room temperature of 10-15 ℃, pouring the mixture into a mold, molding under the action of a 40MPa press machine, taking out the press-molded building block, and conveying the building block to a curing site for natural curing.

Example 4

Mixing 350g of red mud, 250g of fly ash, 350g of shale ceramic sand, 55g of cement, 80g of lime, 25g of straw fiber, 18g of early strength agent and 140g of water (wherein the red mud, the fly ash and the ceramsite are dehydrated and dried, and are mixed with water and an early strength water reducing agent after ball milling), fully stirring, aging for 24 hours at the room temperature of 10-15 ℃, pouring the mixture into a mold, molding under the action of a 40MPa press machine, taking out the press-molded building block, and conveying the building block to a curing site for natural curing.

And (3) performing tests and performance detection according to the national standard GB/T2542 + 2012 of the wall brick test method. Adding water into the mixture, fully stirring the mixture in a stirrer, aging the mixture according to the aging time, pouring the mixture into a mold, forming the mixture under the action of a 40MPa press, taking out the pressed and formed building block, conveying the building block to a curing field, and naturally curing the building block for 28 days to obtain the finished product brick.

Table 1 shows the ratio and mechanical property test of each example

The reasonable determination value and classification of the mechanical properties of the baking-free bricks by the national standard are shown in the following table 2.

TABLE 2 Strength grade determination standards

The baking-free brick prepared according to the proportion in the table 1 is maintained for 28 days, is clean in appearance, has no defects, is high in compressive strength, strong in dry shrinkage resistance and good in anti-permeability, does not generate a blooming phenomenon after being placed for a long time, and the experimental result shows that the baking-free brick can meet the strength requirements of national standards on MU15 and MU 20.

The invention is characterized in that the fly ash pottery sand or the shale pottery sand is used as a heat insulation material, so that the heat conductivity of the building block is reduced, and the heat insulation performance of the heat insulation brick is obviously improved; the early strength is high, and the later strength can reach the national standard.

The invention has the advantages of simple forming process, normal-temperature rapid reaction and solidification, no sintering and no autoclaving, and the product has high compressive strength, strong dry shrinkage resistance, good anti-permeability performance and no scumming phenomenon after long-term storage. The method has the advantages of large utilization of industrial waste, energy and resource saving, low cost, low energy consumption, and obvious economic, environmental and social benefits.

Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the detailed description is made with reference to the embodiments of the present invention, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which shall be covered by the claims.

Claims (1)

1. The red mud-fly ash high-strength heat-insulation building block based on alkali excitation is characterized in that: the components of the material are as follows: 300g of red mud, 200g of fly ash, 300g of ceramic sand, 60g of cement, 50g of lime, 20g of straw fiber, 13g of early strength agent and 125g of water;

the early strength agent is prepared by compounding 20% of ferric chloride, 40% of sodium carbonate and 40% of triethanolamine;

the red mud is industrial waste residue generated by extracting aluminum oxide in the aluminum production industry, and is dried and crushed until the particle size of the red mud is less than 0.15 mm;

the fly ash is collected by crushing, grinding, high-fineness grinding and high-temperature or combustion treatment of coal gangue;

the lime is quicklime;

the cement is ordinary portland cement;

the ceramic sand is shale ceramic sand;

the preparation method comprises the following steps:

(1) and drying: drying the red mud and the fly ash by using a dryer to remove free moisture in the red mud and the fly ash;

(2) and grinding: putting the red mud, the fly ash and the ceramic sand into a ball mill for grinding until the specific surface area is more than 600m²/kg；

(3) Mixing and aging: fully stirring and mixing red mud, fly ash, ceramic sand, cement, lime, straw fiber, an early strength agent and water in a stirrer, and aging for 24 hours at the room temperature of 10-15 ℃;

(4) and pressure forming: pouring the mixture into a mold, and molding under the action of a 40MPa press;

(5) and naturally maintaining: and taking out the pressed building block, and conveying the building block to a maintenance site for natural maintenance.

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