Concrete expansive agent based on secondary aluminum ash as well as preparation method and application of concrete expansive agent

Abstract

The invention discloses a concrete expansive agent based on secondary aluminum ash and a preparation method and application thereof, and relates to the technical field of concrete expansive agents. The concrete expansive agent based on the secondary aluminum ash is prepared from the following components in percentage by weight: 30-50wt% of secondary aluminum ash; 20 to 40 wt% of cement; 5 to 10 wt% of gypsum; 5 to 10 weight percent of lime; 2-5 wt% of an exciting agent; 5 to 10 weight percent of attapulgite; in the secondary aluminum ash, Al is not less than 12%, Cl <-> is less than 0.1%, and the specific surface area is greater than 400m < 2 > / kg. The secondary aluminum ash, the attapulgite and other components are compounded, and the addition amount of each component is limited, so that the concrete expansive agent prepared based on the secondary aluminum ash with low aluminum content can have excellent performance, the expansion rate of concrete can be greatly reduced, the impermeability and crack resistance of the concrete can be improved, and the concrete expansive agent can be used as a concrete expansive agent. And the 7d / 28d compressive strength and other properties of the concrete can be improved to a certain extent.

Description

Technical Field

[0001] The present application relates to the technical field of concrete expansion agents, and particularly to a concrete expansion agent based on secondary aluminum ash, its preparation method and application. Background Art

[0002] Aluminum ash is a by-product in the traditional aluminum industry, which is generated during the high-temperature process of aluminum smelting. In recent years, China's aluminum production capacity has been increasing year by year, and most aluminum production enterprises adopt the methods of stacking and burying aluminum ash, which is not only a waste of resources, but also causes environmental pollution. How to efficiently utilize aluminum ash resources and reduce the impact on the ecological environment is an effective way to solve the resource, energy and environmental constraints in economic and social development and ensure the development of the aluminum industry.

[0003] Primary aluminum ash can be used in concrete expansion agents. However, due to the low aluminum content in secondary aluminum ash, the performance of the prepared concrete expansion agent is poor. Therefore, how to apply secondary aluminum ash in concrete expansion agents is a technical problem to be solved at present. Summary of the Invention

[0004] In order to solve at least one of the above technical problems and develop an application of secondary aluminum ash in concrete expansion agents, the present application provides a concrete expansion agent based on secondary aluminum ash, its preparation method and application.

[0005] On the one hand, a concrete expansion agent based on secondary aluminum ash provided by the present application is prepared from components including the following in percentage by weight:

[0006] Secondary aluminum ash: 30 - 50 wt%;

[0007] Cement: 20 - 40 wt%;

[0008] Gypsum: 5 - 10 wt%;

[0009] Lime: 5 - 10 wt%;

[0010] Activator: 2 - 5 wt%;

[0011] Attapulgite: 5 - 10 wt%;

[0012] In the secondary aluminum ash, Al ≥ 12%, Cl - <0.1%, and the specific surface area > 400 m 2 / kg.

[0013] Optionally, the particle size of the attapulgite is 0.2 - 10 μm.

[0014] Optionally, the weight ratio of the secondary aluminum ash to the attapulgite is 5 - 5.7:1.

[0015] Optionally, the cement used is sulfoaluminate cement.

[0016] Optionally, the activator is sodium hydroxide or sodium silicate.

[0017] In a second aspect, the present application provides a method for preparing the above concrete expansive agent, comprising the following steps:

[0018] S1. Pretreatment

[0019] The secondary aluminum ash is first subjected to water washing treatment or pickling treatment, then calcination treatment, and ball milling treatment after the calcination treatment;

[0020] S2. Mixing

[0021] The pretreated secondary aluminum ash in S1 is mixed with attapulgite according to the formula amount, and then the cement, gypsum, lime and activator in the formula amount are added, and uniformly mixed to obtain a powdery concrete expansive agent.

[0022] Optionally, in the calcination treatment, the calcination temperature is 600-800 °C, and the calcination time is 0.5-1 h.

[0023] Optionally, it further includes S3. Compression molding

[0024] The prepared powdery concrete expansive agent is compression molded to obtain a granular concrete expansive agent.

[0025] In a third aspect, the present application provides the application of the above concrete expansive agent in the field of concrete

[0026] In summary, the present invention makes the concrete expansive agent prepared based on the secondary aluminum ash with low aluminum content have excellent performance by compounding the secondary aluminum ash with attapulgite and other components and limiting the addition amount of each component. It can not only greatly reduce the expansion rate of concrete, improve the impermeability and crack resistance of concrete, but also improve the performance such as 7d / 28d compressive strength of concrete to a certain extent. Detailed embodiments

[0027] The following further details the present application in conjunction with embodiments.

[0028] In the following embodiments of the present application, unless otherwise specified, the main components involved are all purchased from commercially available products.

[0029] In the following embodiments of the present application, the cement is exemplarily sulfur aluminate cement, purchased from Anhui Tongling Conch Cement Co., Ltd. The activator is exemplarily sodium silicate. For the secondary aluminum ash used in the following embodiments of the present application, it needs to be detected first. Those with an aluminum content lower than 12% need to be treated separately. Among the qualified secondary aluminum ash in terms of aluminum content, if Cl - <0.1%, specific surface area>400m 2It can be used directly at / kg, otherwise it needs to be pretreated through the preparation examples. Specific embodiments

[0031] Preparation examples

[0032] The secondary aluminum ash used in this preparation example was inspected for incoming materials with Al = 13.5%, Cl - = 0.23%, specific surface area = 320 m 2 / kg.

[0033] First, the secondary aluminum ash is pickled to reduce the Cl content in the secondary aluminum ash - , then calcined at 600 °C for 1 h to improve the activity of the secondary aluminum ash, and then ball-milled to increase the specific surface area of the secondary aluminum ash; in the pretreated secondary aluminum ash: Al = 13.7%, Cl - = 0.08%, specific surface area = 460 m 2 / kg.

[0034] Example 1

[0035] This example is used to prepare a concrete expansion agent, specifically as follows: 3 kg of the pretreated secondary aluminum ash in the preparation example is mixed with 1 kg of attapulgite clay, and then 3.8 kg of cement, 1 kg of gypsum, 1 kg of lime and 0.2 g of activator are added, and mixed evenly to obtain a powdery concrete expansion agent.

[0036] Example 2

[0037] This example is used to prepare a concrete expansion agent, specifically as follows: 3.5 kg of the pretreated secondary aluminum ash in the preparation example is mixed with 1 kg of attapulgite clay, and then 3.5 kg of cement, 0.8 kg of gypsum, 1 kg of lime and 0.2 g of activator are added, and mixed evenly to obtain a powdery concrete expansion agent.

[0038] Example 3

[0039] This example is used to prepare a concrete expansion agent, specifically as follows: 4 kg of the pretreated secondary aluminum ash in the preparation example is mixed with 0.8 kg of attapulgite clay, and then 3.7 kg of cement, 0.5 kg of gypsum, 0.8 kg of lime and 0.2 g of activator are added, and mixed evenly to obtain a powdery concrete expansion agent.

[0040] Example 4

[0041] This example is used to prepare a concrete expansion agent, specifically as follows: 4.5 kg of the pretreated secondary aluminum ash in the preparation example is mixed with 0.8 kg of attapulgite clay, and then 3.2 kg of cement, 0.8 kg of gypsum, 0.5 kg of lime and 0.2 g of activator are added, and mixed evenly to obtain a powdery concrete expansion agent.

[0042] Example 5

[0043] This example is used to prepare a concrete expansion agent, specifically as follows: 5 kg of the treated secondary aluminum ash in the preparation example is mixed with 0.2 kg of attapulgite, and then 2.5 kg of cement, 1 kg of gypsum, 0.8 kg of lime, and 0.2 g of activator are added. After mixing evenly, a powdery concrete expansion agent is obtained.

[0044] Comparative Example 1

[0045] This comparative example is used to prepare a concrete expansion agent, specifically as follows: 3 kg of the treated secondary aluminum ash in the preparation example is mixed with 3.8 kg of cement, 1 kg of gypsum, 1 kg of lime, and 0.2 g of activator. After mixing evenly, a powdery concrete expansion agent is obtained.

[0046] Comparative Example 2

[0047] This comparative example is used to prepare a concrete expansion agent, specifically as follows: 3.5 kg of the treated secondary aluminum ash in the preparation example is mixed with 3.5 kg of cement, 0.8 kg of gypsum, 1 kg of lime, and 0.2 g of activator. After mixing evenly, a powdery concrete expansion agent is obtained.

[0048] Comparative Example 3

[0049] This comparative example is used to prepare a concrete expansion agent, specifically as follows: 4 kg of the treated secondary aluminum ash in the preparation example is mixed with 3.7 kg of cement, 0.5 kg of gypsum, 0.8 kg of lime, and 0.2 g of activator. After mixing evenly, a powdery concrete expansion agent is obtained.

[0050] Comparative Example 4

[0051] This comparative example is used to prepare a concrete expansion agent, specifically as follows: 4.5 kg of the treated secondary aluminum ash in the preparation example is mixed with 3.2 kg of cement, 0.8 kg of gypsum, 0.5 kg of lime, and 0.2 g of activator. After mixing evenly, a powdery concrete expansion agent is obtained.

[0052] Comparative Example 5

[0053] This comparative example is used to prepare a concrete expansion agent, specifically as follows: 5 kg of the treated secondary aluminum ash in the preparation example is mixed with 2.5 kg of cement, 1 kg of gypsum, 0.8 kg of lime, and 0.2 g of activator. After mixing evenly, a powdery concrete expansion agent is obtained.

[0054] The concrete expansion agents prepared in the above Examples 1 - 5 and Comparative Examples 1 - 5 are added to C35 concrete at an addition amount of 6%, and their performances are detected. The detection results are shown in Table 1.

[0055] Table 1

[0056]

[0057]

[0058] From Examples 1 - 5, Comparative Examples 1 - 5, the blank group and Table 1, it can be seen that adding the concrete expansion agent prepared in this application not only does not reduce the 7d / 28d compressive strength of the concrete, but also enhances it; the expansion rate of the concrete does not exceed 0.03%, far lower than 0.06% of the blank group, and also significantly lower than 0.04 - 0.05% corresponding to Comparative Examples 1 - 5; moreover, the impermeability, crack resistance and carbonation resistance of the concrete have all been significantly improved; therefore, it can be known that the concrete expansion agent prepared in this application can, on the basis of using secondary aluminum ash with a relatively low aluminum content as a raw material, by changing the components and addition amounts in the formula, significantly improve the performance.

[0059] The inventor further analyzed Table 1 and found that the performance of the concrete expansion agents corresponding to Examples 3 - 4 is significantly better than that of Examples 1 - 2 and Example 5; the inventor made the following Examples 6 - 13 for further verification.

[0060] Among them, in Examples 6 - 9, on the basis of Example 3, only the addition amount of secondary aluminum ash is changed to change the weight ratio of secondary aluminum ash to attapulgite, and other components, addition amounts and preparation methods remain unchanged; specifically as follows.

[0061] Example 6

[0062] This example is used to prepare a concrete expansion agent, specifically as follows: Mix 3 kg of the treated secondary aluminum ash in the preparation example with 0.8 kg of attapulgite, then add 3.7 kg of cement, 0.5 kg of gypsum, 0.8 kg of lime and 0.2 g of activator, and mix evenly to obtain a powdery concrete expansion agent.

[0063] Example 7

[0064] This example is used to prepare a concrete expansion agent, specifically as follows: Mix 3.5 kg of the treated secondary aluminum ash in the preparation example with 0.8 kg of attapulgite, then add 3.7 kg of cement, 0.5 kg of gypsum, 0.8 kg of lime and 0.2 g of activator, and mix evenly to obtain a powdery concrete expansion agent.

[0065] Example 8

[0066] This example is used to prepare a concrete expansion agent, specifically as follows: Mix 4.5 kg of the treated secondary aluminum ash in the preparation example with 0.8 kg of attapulgite, then add 3.7 kg of cement, 0.5 kg of gypsum, 0.8 kg of lime and 0.2 g of activator, and mix evenly to obtain a powdery concrete expansion agent.

[0067] Example 9

[0068] This example is used to prepare a concrete expansive agent, specifically as follows: 5 kg of the treated secondary aluminum ash in the preparation example is mixed with 0.8 kg of attapulgite clay, and then 3.7 kg of cement, 0.5 kg of gypsum, 0.8 kg of lime, and 0.2 g of activator are added. After mixing evenly, a powdery concrete expansive agent is obtained.

[0069] The concrete expansive agents prepared in Examples 6 - 9 above are added to C35 concrete at an addition amount of 6%, and their performance is detected. The detection results are shown in Table 2.

[0070] Table 2

[0071]

[0072] It can be seen from Example 3, Examples 6 - 9, and Table 2 that the concrete expansive agents prepared in Example 3 and Example 8 have a significant improvement in the 7d / 28d compressive strength of concrete compared to other examples; the expansion rate is smaller, not exceeding 0.01%; the impermeability reaches the P6 level; the width of the cracks is less than 0.05 mm; the carbonation depth at 28d also does not exceed 3 mm; therefore, it can be known that when the weight ratio of secondary aluminum ash to attapulgite clay in the technical solution of this application is between 5 and 5.7, the comprehensive performance of the prepared concrete expansive agent is better.

[0073] Among them, in Examples 10 - 13, based on Example 4, only the addition amount of secondary aluminum ash is changed to change the weight ratio of secondary aluminum ash to attapulgite clay, and other components, addition amounts, and preparation methods remain unchanged; specifically as follows.

[0074] Example 10

[0075] This example is used to prepare a concrete expansive agent, specifically as follows: 3 kg of the treated secondary aluminum ash in the preparation example is mixed with 0.8 kg of attapulgite clay, and then 3.2 kg of cement, 0.8 kg of gypsum, 0.5 kg of lime, and 0.2 g of activator are added. After mixing evenly, a powdery concrete expansive agent is obtained.

[0076] Example 11

[0077] This example is used to prepare a concrete expansive agent, specifically as follows: 3.5 kg of the treated secondary aluminum ash in the preparation example is mixed with 0.8 kg of attapulgite clay, and then 3.2 kg of cement, 0.8 kg of gypsum, 0.5 kg of lime, and 0.2 g of activator are added. After mixing evenly, a powdery concrete expansive agent is obtained.

[0078] Example 12

[0079] This example is used to prepare a concrete expansion agent, specifically as follows: Mix 4 kg of the treated secondary aluminum ash in the preparation example with 0.8 kg of attapulgite clay, and then add 3.2 kg of cement, 0.8 kg of gypsum, 0.5 kg of lime, and 0.2 g of activator, and mix evenly to obtain a powdery concrete expansion agent.

[0080] Example 13

[0081] This example is used to prepare a concrete expansion agent, specifically as follows: Mix 5 kg of the treated secondary aluminum ash in the preparation example with 0.8 kg of attapulgite clay, and then add 3.2 kg of cement, 0.8 kg of gypsum, 0.5 kg of lime, and 0.2 g of activator, and mix evenly to obtain a powdery concrete expansion agent.

[0082] Add the concrete expansion agents prepared in Examples 10 to 13 above to C35 concrete at an addition amount of 6%, and conduct performance tests on it. The test results are shown in Table 3.

[0083] Table 3

[0084]

[0085] It can be seen from Example 4, Examples 10 to 13, and Table 3 that the concrete expansion agents prepared in Example 4 and Example 12 have a significant improvement in the 7d / 28d compressive strength of concrete compared to other examples; the expansion rate is smaller, not exceeding 0.01%; the impermeability reaches the P6 level; the width of the cracks is less than 0.05 mm; the carbonation depth at 28d does not exceed 3 mm either; therefore, it can be known that when the weight ratio of secondary aluminum ash to attapulgite clay in the technical solution of this application is between 5 and 5.7, the comprehensive performance of the prepared concrete expansion agent is better.

[0086] The above are all the preferred embodiments of this application. It does not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A concrete expansion agent based on secondary aluminum ash, characterized in that, Prepared from components comprising the following by weight percentage: Secondary aluminum ash 30 - 50 wt%; Cement 20 - 40 wt%; Gypsum 5 - 10 wt%; Lime 5 - 10 wt%; Activator 2 - 5 wt%; Attapulgite 5 - 10 wt%; The Al in the secondary aluminum ash is ≥12%, Cl - <0.1%, and the specific surface area > 400 m2 / kg.

2. The concrete expansion agent according to claim 1, wherein The particle size of the attapulgite is 0.2 - 10 μm.

3. The concrete expansion agent according to claim 1, characterized in that, The weight ratio of the secondary aluminum ash to the attapulgite is 5 - 5.7:

1.

4. The concrete expansion agent according to claim 1, wherein The cement used is sulfoaluminate cement.

5. The concrete expansion agent according to claim 1, characterized in that, The activator used is sodium hydroxide or sodium silicate.

6. The preparation method of the concrete expansion agent according to claim 1, characterized in that, Including the following steps: S1. Pretreatment The secondary aluminum ash is first subjected to water washing treatment or pickling treatment, then to calcination treatment, and after the calcination treatment, ball milling treatment is carried out; S2. Mixing The pretreated secondary aluminum ash and attapulgite in S1 are mixed according to the formulation amount, and then the formulation amounts of cement, gypsum, lime and activator are added, and mixed evenly to obtain a powdery concrete expansion agent.

7. The concrete expansive agent according to claim 1, characterized in that, In the calcination treatment, the calcination temperature is 600 - 800 °C, and the calcination time is 0.5 - 1 h.

8. The preparation method according to claim 1, characterized in that, Also including S3. Compression molding The prepared powdery concrete expansion agent is made into a granular concrete expansion agent by compression molding.

9. Application of the concrete expansion agent according to claim 1 in the field of concrete.

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