A method for producing autoclaved aerated concrete

Abstract

The application discloses a preparation method of autoclaved aerated concrete. The preparation method of the autoclaved aerated concrete comprises the following steps: preparation of first modified iron tailing powder, preparation of second modified iron tailing powder, ball milling and pulping, pouring and static standing, and steam curing. The application provides a preparation method of autoclaved aerated concrete, which is helpful to realize recycling of waste, reduce environmental burden, save resources and improve environmental protection performance of products by using waste such as iron tailings and steel slag.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a method for preparing autoclaved aerated concrete. Background Technology

[0002] With the rapid development of urbanization in my country, the proportion of building energy consumption in the total social commodity energy consumption is also continuously increasing, and its impact on national economic development and people's normal work and life is becoming increasingly prominent. Therefore, it is imperative to carry out research on building energy conservation. Traditional red bricks and ordinary concrete products can no longer meet the needs of resource and environmental protection and the development of modern buildings. As a new type of multifunctional wall material that makes full use of industrial waste and improves the environment, aerated concrete has the advantages of being lightweight, energy-saving and waste-utilizing, heat-insulating and sound-absorbing, and is one of the priority varieties for the entire construction industry in the future.

[0003] Currently, the solid waste generated from tailings not only occupies a large amount of land resources but also pollutes the environment, sometimes even blocking rivers or damaging farmland vegetation. Furthermore, due to the generally low level of utilization technology and low utilization efficiency, a large amount of new tailings continues to accumulate every year, gradually increasing the burden on the environment. Summary of the Invention

[0004] To address the technical problems of low overall utilization level and low utilization efficiency of solid waste generated from tailings, which have led to a gradually increasing environmental burden, this invention provides a method for preparing autoclaved aerated concrete. By using waste materials such as iron tailings and steel slag, this method helps to achieve waste recycling, reduce environmental burden, save resources, and improve the environmental performance of the product.

[0005] This invention provides a method for preparing autoclaved aerated concrete, comprising the following steps: Step 1: Preparation of the first modified iron tailings powder: Take an appropriate amount of the first iron tailings powder, water and alkaline modifier, mix them well and heat them to obtain the first modified iron tailings powder. Step 2: Preparation of the second modified iron tailings powder: Take appropriate amounts of the second iron tailings powder, alkali modifier, water, steel slag and lignin fiber, mix them, and then perform oxidation treatment. After dehydration, the second modified iron tailings powder is obtained. Step 3, ball milling to prepare slurry: Take appropriate amounts of water, sand and phosphogypsum, mix them evenly and then ball mill to obtain the first slurry; add appropriate amounts of cement, quicklime, the first modified iron tailings powder and the second iron tailings powder to the first slurry, stir evenly to obtain the second slurry; add appropriate amounts of aluminum powder to the second slurry, stir again to obtain the third slurry. Step 4: Casting and Static Stopping: The third slurry is injected into the mold and allowed to stand for gas generation to obtain the green body; Step 5, Steam curing: The preform is transferred into an autoclave for steam curing. After curing, the air is released, the preform is removed, and then the preform is transferred into a drying oven to dry to constant weight before being removed to obtain autoclaved aerated concrete.

[0006] In a preferred embodiment of the method for preparing autoclaved aerated concrete provided by the present invention, in step one, the weight ratio of the first iron tailings powder, the water and the alkali modifier is 100:100~200:0.1~1.

[0007] In a preferred embodiment of the method for preparing autoclaved aerated concrete provided by the present invention, the particle size of the first iron tailings powder is 300-400 mesh.

[0008] In a preferred embodiment of the method for preparing autoclaved aerated concrete provided by the present invention, the heat treatment is performed at 50~70℃ for 1~1.5h, while stirring.

[0009] In a preferred embodiment of the method for preparing autoclaved aerated concrete provided by the present invention, in step two, the weight ratio of the second iron tailings powder, the alkali modifier, the water, the steel slag and the lignin fiber is 100:0.1~0.5:100~200:20~30:10~15.

[0010] In a preferred embodiment of the method for preparing autoclaved aerated concrete provided by the present invention, the particle size of the second iron tailings powder is 100-200 mesh.

[0011] In a preferred embodiment of the method for preparing autoclaved aerated concrete provided by the present invention, the oxidation treatment is performed by treating the material in an oxygen atmosphere at 80-90°C for 1-1.5 hours.

[0012] In a preferred embodiment of the method for preparing autoclaved aerated concrete provided by the present invention, in step three, the weight ratio of water, sand, phosphogypsum, cement, quicklime, the first modified iron tailings powder, the second iron tailings powder, and aluminum powder is 200~250:170~200:20~25:60~70:55~65:30~50:50~70:1~1.4.

[0013] In a preferred embodiment of the method for preparing autoclaved aerated concrete provided by the present invention, in step four, the mold after the third slurry is injected is placed in a drying oven at 45~55℃ for static gas generation.

[0014] In a preferred embodiment of the method for preparing autoclaved aerated concrete provided by the present invention, the autoclaving is performed by maintaining a constant temperature and pressure of 1.0~1.2MPa, a vacuum degree of -0.06 MPa to -0.07MPa, and a constant temperature time of 5~7h.

[0015] Compared with existing technologies, the method for preparing autoclaved aerated concrete provided by this invention has the following beneficial effects: by using waste materials such as iron tailings and steel slag, it helps to realize the recycling of waste materials, reduce the environmental burden, save resources, and improve the environmental performance of products; and after modification treatment, iron tailings powder can effectively improve the compressive strength of autoclaved aerated concrete. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a flowchart of the method for preparing autoclaved aerated concrete provided by the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1 , Figure 1 This is a flowchart of the method for preparing autoclaved aerated concrete provided by the present invention. Example 1

[0019] A method for preparing autoclaved aerated concrete includes the following steps: Step 1: Preparation of the first modified iron tailings powder: Take appropriate amounts of the first iron tailings powder, water, and alkaline modifier, mix them thoroughly, and then heat-treat to obtain the first modified iron tailings powder; the weight ratio of the first iron tailings powder, the water, and the alkaline modifier is 100:100:0.1; the particle size of the first iron tailings powder is 300~400 mesh; the heat treatment is carried out at 50℃ for 1 hour while stirring. Step 2: Preparation of the second modified iron tailings powder: Take appropriate amounts of the second iron tailings powder, alkali modifier, water, steel slag, and lignin fiber, mix them evenly, and then perform oxidation treatment. After dehydration, the second modified iron tailings powder is obtained. The weight ratio of the second iron tailings powder, the alkali modifier, the water, the steel slag, and the lignin fiber is 100:0.1:100:20:10. The particle size of the second iron tailings powder is 100~200 mesh. The oxidation treatment is performed at 80°C in an oxygen atmosphere for 1 hour. Step 3, Ball Milling for Slurry Preparation: Take appropriate amounts of water, sand, and phosphogypsum, mix them evenly, and then ball mill to obtain the first slurry; add appropriate amounts of cement, quicklime, the first modified iron tailings powder, and the second iron tailings powder to the first slurry, and stir evenly to obtain the second slurry; add appropriate amounts of aluminum powder to the second slurry, and stir again to obtain the third slurry; the weight ratio of the water, sand, phosphogypsum, cement, quicklime, the first modified iron tailings powder, the second iron tailings powder, and aluminum powder is 200:170:20:60:55:30:50:1; Step 4, Casting and Static Stopping: The third slurry is injected into the mold, and then the mold after the third slurry is injected is placed in a drying oven at 45~55℃ for static stopping and gas generation to obtain the green body; Step 5, Steam Curing: The preform is transferred into an autoclave for steam curing. After curing, the air is vented, the preform is removed, and then the preform is transferred into a drying oven to dry to constant weight before being removed to obtain autoclaved aerated concrete. The steam curing process is as follows: maintaining a constant temperature and pressure of 1.0~1.2MPa, a vacuum degree of -0.06MPa to -0.07MPa, and a constant temperature time of 5~7h. Example 2

[0020] A method for preparing autoclaved aerated concrete includes the following steps: Step 1: Preparation of the first modified iron tailings powder: Take appropriate amounts of the first iron tailings powder, water, and alkaline modifier, mix them thoroughly, and then heat-treat to obtain the first modified iron tailings powder; the weight ratio of the first iron tailings powder, water, and alkaline modifier is 100:200:1; the particle size of the first iron tailings powder is 300~400 mesh; the heat treatment is carried out at 70℃ for 1.5 hours with stirring. Step 2: Preparation of the second modified iron tailings powder: Take appropriate amounts of the second iron tailings powder, alkali modifier, water, steel slag, and lignin fiber, mix them evenly, and then perform oxidation treatment. After dehydration, the second modified iron tailings powder is obtained. The weight ratio of the second iron tailings powder, the alkali modifier, the water, the steel slag, and the lignin fiber is 100:0.5:200:30:15. The particle size of the second iron tailings powder is 100~200 mesh. The oxidation treatment is carried out in an oxygen atmosphere at 90°C for 1.5 hours. Step 3, Ball Milling for Slurry Preparation: Take appropriate amounts of water, sand, and phosphogypsum, mix them evenly, and then ball mill to obtain the first slurry; add appropriate amounts of cement, quicklime, the first modified iron tailings powder, and the second iron tailings powder to the first slurry, and stir evenly to obtain the second slurry; add appropriate amounts of aluminum powder to the second slurry, and stir again to obtain the third slurry; the weight ratio of the water, sand, phosphogypsum, cement, quicklime, the first modified iron tailings powder, the second iron tailings powder, and aluminum powder is 250:200:25:70:65:50:70:1.4; Step 4, Casting and Static Stopping: The third slurry is injected into the mold, and then the mold after the third slurry is injected is placed in a drying oven at 45~55℃ for static stopping and gas generation to obtain the green body; Step 5, Steam Curing: The preform is transferred into an autoclave for steam curing. After curing, the air is vented, the preform is removed, and then the preform is transferred into a drying oven to dry to constant weight before being removed to obtain autoclaved aerated concrete. The steam curing process is as follows: maintaining a constant temperature and pressure of 1.0~1.2MPa, a vacuum degree of -0.06MPa to -0.07MPa, and a constant temperature time of 5~7h. Example 3

[0021] A method for preparing autoclaved aerated concrete includes the following steps: Step 1: Preparation of the first modified iron tailings powder: Take appropriate amounts of the first iron tailings powder, water, and alkaline modifier, mix them thoroughly, and then heat-treat to obtain the first modified iron tailings powder; the weight ratio of the first iron tailings powder, water, and alkaline modifier is 100:50:0.6; the particle size of the first iron tailings powder is 300~400 mesh; the heat treatment is carried out at 60℃ for 1.2 hours with stirring. Step 2: Preparation of the second modified iron tailings powder: Take appropriate amounts of the second iron tailings powder, alkali modifier, water, steel slag, and lignin fiber, mix them evenly, and then perform oxidation treatment. After dehydration, the second modified iron tailings powder is obtained. The weight ratio of the second iron tailings powder, the alkali modifier, the water, the steel slag, and the lignin fiber is 100:0.3:150:25:13. The particle size of the second iron tailings powder is 100~200 mesh. The oxidation treatment is carried out in an oxygen atmosphere at 85°C for 1.2 hours. Step 3, Ball Milling for Slurry Preparation: Take appropriate amounts of water, sand, and phosphogypsum, mix them evenly, and then ball mill to obtain the first slurry; add appropriate amounts of cement, quicklime, the first modified iron tailings powder, and the second iron tailings powder to the first slurry, and stir evenly to obtain the second slurry; add appropriate amounts of aluminum powder to the second slurry, and stir again to obtain the third slurry; the weight ratio of the water, sand, phosphogypsum, cement, quicklime, the first modified iron tailings powder, the second iron tailings powder, and aluminum powder is 220:190:22:65:60:40:60:1.2; Step 4, Casting and Static Stopping: The third slurry is injected into the mold, and then the mold after the third slurry is injected is placed in a drying oven at 45~55℃ for static stopping and gas generation to obtain the green body; Step 5, Steam Curing: The preform is transferred into an autoclave for steam curing. After curing, the air is vented, the preform is removed, and then the preform is transferred into a drying oven to dry to constant weight before being removed to obtain autoclaved aerated concrete. The steam curing process is as follows: maintaining a constant temperature and pressure of 1.0~1.2MPa, a vacuum degree of -0.06MPa to -0.07MPa, and a constant temperature time of 5~7h. Example 4

[0022] A method for preparing autoclaved aerated concrete includes the following steps: Step 1: Preparation of the first modified iron tailings powder: Take appropriate amounts of the first iron tailings powder, water, and alkaline modifier, mix them thoroughly, and then heat-treat to obtain the first modified iron tailings powder; the weight ratio of the first iron tailings powder, the water, and the alkaline modifier is 100:120:0.7; the particle size of the first iron tailings powder is 300~400 mesh; the heat treatment is carried out at 65℃ for 1.4 hours with stirring. Step 2: Preparation of the second modified iron tailings powder: Take appropriate amounts of the second iron tailings powder, alkali modifier, water, steel slag, and lignin fiber, mix them evenly, and then perform oxidation treatment. After dehydration, the second modified iron tailings powder is obtained. The weight ratio of the second iron tailings powder, the alkali modifier, the water, the steel slag, and the lignin fiber is 100:0.4:180:22:12. The particle size of the second iron tailings powder is 100~200 mesh. The oxidation treatment is carried out in an oxygen atmosphere at 80℃ for 1.5 hours. Step 3, Ball Milling for Slurry Preparation: Take appropriate amounts of water, sand, and phosphogypsum, mix them evenly, and then ball mill to obtain the first slurry; add appropriate amounts of cement, quicklime, the first modified iron tailings powder, and the second iron tailings powder to the first slurry, and stir evenly to obtain the second slurry; add appropriate amounts of aluminum powder to the second slurry, and stir again to obtain the third slurry; the weight ratio of the water, sand, phosphogypsum, cement, quicklime, the first modified iron tailings powder, the second iron tailings powder, and aluminum powder is 220:180:22:63:57:35:55:1.1; Step 4, Casting and Static Stopping: The third slurry is injected into the mold, and then the mold after the third slurry is injected is placed in a drying oven at 45~55℃ for static stopping and gas generation to obtain the green body; Step 5, Steam Curing: The preform is transferred into an autoclave for steam curing. After curing, the air is vented, the preform is removed, and then the preform is transferred into a drying oven to dry to constant weight before being removed to obtain autoclaved aerated concrete. The steam curing process is as follows: maintaining a constant temperature and pressure of 1.0~1.2MPa, a vacuum degree of -0.06MPa to -0.07MPa, and a constant temperature time of 5~7h. Example 5

[0023] A method for preparing autoclaved aerated concrete includes the following steps: Step 1: Preparation of the first modified iron tailings powder: Take appropriate amounts of the first iron tailings powder, water, and alkaline modifier, mix them thoroughly, and then heat-treat to obtain the first modified iron tailings powder; the weight ratio of the first iron tailings powder, water, and alkaline modifier is 100:180:0.8; the particle size of the first iron tailings powder is 300~400 mesh; the heat treatment is carried out at 55℃ for 1.1 hours with stirring. Step 2: Preparation of the second modified iron tailings powder: Take appropriate amounts of the second iron tailings powder, alkali modifier, water, steel slag, and lignin fiber, mix them evenly, and then perform oxidation treatment. After dehydration, the second modified iron tailings powder is obtained. The weight ratio of the second iron tailings powder, the alkali modifier, the water, the steel slag, and the lignin fiber is 100:0.2:120:27:14. The particle size of the second iron tailings powder is 100~200 mesh. The oxidation treatment is carried out in an oxygen atmosphere at 90°C for 1 hour. Step 3, Ball Milling for Slurry Preparation: Take appropriate amounts of water, sand, and phosphogypsum, mix them evenly, and then ball mill to obtain the first slurry; add appropriate amounts of cement, quicklime, the first modified iron tailings powder, and the second iron tailings powder to the first slurry, and stir evenly to obtain the second slurry; add appropriate amounts of aluminum powder to the second slurry, and stir again to obtain the third slurry; the weight ratio of the water, sand, phosphogypsum, cement, quicklime, the first modified iron tailings powder, the second iron tailings powder, and aluminum powder is 240:190:24:68:64:48:65:1.3; Step 4, Casting and Static Stopping: The third slurry is injected into the mold, and then the mold after the third slurry is injected is placed in a drying oven at 45~55℃ for static stopping and gas generation to obtain the green body; Step 5, Steam Curing: The preform is transferred into an autoclave for steam curing. After curing, the air is vented, the preform is removed, and then the preform is transferred into a drying oven to dry to constant weight before being removed to obtain autoclaved aerated concrete. The steam curing process is as follows: maintaining a constant temperature and pressure of 1.0~1.2MPa, a vacuum degree of -0.06MPa to -0.07MPa, and a constant temperature time of 5~7h.

[0024] experiment The aerated concrete product was cut into several standard test specimens with dimensions of 100mm*100mm*100mm, and compressive strength and splitting tensile strength were tested. The results are shown in the table below: Splitting tensile strength / MPa 1.03 1.15 1.08 1.07 1.05 Compressive strength / MPa 8.1 9.3 9.1 8.7 9.2 The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing autoclaved aerated concrete, characterized in that, Includes the following steps: Step 1: Preparation of the first modified iron tailings powder: Take appropriate amounts of the first iron tailings powder, water, and alkaline modifier, mix them thoroughly, and then heat-treat to obtain the first modified iron tailings powder; the weight ratio of the first iron tailings powder, water, and alkaline modifier is 100:100~200:0.1~1; the particle size of the first iron tailings powder is 300~400 mesh; Step 2: Preparation of the second modified iron tailings powder: Take appropriate amounts of the second iron tailings powder, alkali modifier, water, steel slag, and lignin fiber, mix them evenly, and then perform oxidation treatment. After dehydration, the second modified iron tailings powder is obtained. The weight ratio of the second iron tailings powder, the alkali modifier, the water, the steel slag, and the lignin fiber is 100:0.1~0.5:100~200:20~30:10~15. The particle size of the second iron tailings powder is 100~200 mesh. The oxidation treatment is performed at 80~90℃ in an oxygen atmosphere for 1~1.5 hours. Step 3, Ball Milling for Slurry Preparation: Take appropriate amounts of water, sand, and phosphogypsum, mix them evenly, and then ball mill to obtain the first slurry; add appropriate amounts of cement, quicklime, the first modified iron tailings powder, and the second iron tailings powder to the first slurry, and stir evenly to obtain the second slurry; add appropriate amounts of aluminum powder to the second slurry, and stir again to obtain the third slurry; the weight ratio of the water, sand, phosphogypsum, cement, quicklime, the first modified iron tailings powder, the second iron tailings powder, and aluminum powder is 200~250:170~200:20~25:60~70:55~65:30~50:50~70:1~1.4; Step 4: Casting and Static Stopping: The third slurry is injected into the mold and allowed to stand for gas generation to obtain the green body; Step 5, Steam curing: The green body is transferred into an autoclave for steam curing. After curing, the air is released, the green body is removed, and then the green body is transferred into a drying oven to dry to constant weight before being removed to obtain autoclaved aerated concrete.

2. The method for preparing autoclaved aerated concrete according to claim 1, characterized in that, The heat treatment is performed at 50~70℃ for 1~1.5 hours with stirring.

3. The method for preparing autoclaved aerated concrete according to claim 1, characterized in that, In step four, the mold after the third slurry is injected is placed in a drying oven at 45~55℃ for static gas generation.

4. The method for preparing autoclaved aerated concrete according to claim 1, characterized in that, The autoclaving process involves maintaining a constant temperature and pressure of 1.0~1.2MPa, a vacuum degree of -0.06 MPa to -0.07MPa, and a constant temperature time of 5~7h.

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