Method for preparing high-performance building material from coal-based solid waste

Abstract

The invention relates to the technical field of building materials, in particular to a method for preparing a high-performance building material from coal-based solid waste. The coal gangue and the fly ash are converted into high-performance building materials, so that the pollution of solid wastes to the environment is effectively reduced, and meanwhile, the cyclic utilization of resources is realized. According to the method, exploitation of natural resources is reduced, the environmental pressure of solid waste treatment is relieved, and green development of the building material industry is promoted. The composite alkali-activated catalyst comprises sodium silicate, zinc oxide and titanium dioxide. The catalyst disclosed by the invention has a synergistic effect, and the activity of the coal-based solid waste can be remarkably improved, so that the performance of a final product is improved.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a method for preparing high-performance building materials from coal-based solid waste. Background Art

[0002] As by-products of the coal industry, coal gangue and fly ash are produced in huge quantities during the mining and utilization of coal. The stacking of these solid wastes not only occupies a large amount of land resources, but also causes serious environmental pollution to the soil, water sources and atmosphere due to the harmful substances they contain, such as heavy metals and sulfides. Long-term stacking may also lead to surface water and groundwater pollution, affecting the ecological balance and human health.

[0003] At present, the treatment methods of coal gangue and fly ash mainly include landfill and incineration, which are not only inefficient, but also have the risk of resource waste and secondary pollution. Landfill takes up land resources, and the leachate that may be produced during the landfill process will pollute the environment; incineration will produce harmful gases and pollute the atmospheric environment.

[0004] Therefore, a method for resource utilization of coal-based solid waste needs to be developed urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a method for converting coal gangue and fly ash into high-performance building materials that meet the standards of the construction industry through specific pretreatment, activation and curing steps. The technical solution of the present invention is as follows:

[0006] A method for preparing high-performance building materials from coal-based solid waste comprises the following steps:

[0007] S1. Collect coal gangue and fly ash, crush, screen and dry them respectively, and then mix them evenly according to the proportion;

[0008] S2. The mixed powder obtained in S1 is mixed with calcium hydroxide, and a composite base is added to activate the catalyst, stirred evenly, and allowed to stand to activate the activity;

[0009] S3. Mix the excited coal-based solid waste with cement and aggregate in proportion and stir evenly;

[0010] S4. Pressing the mixture into a shape and then curing it.

[0011] As an improvement, the ratio of coal gangue to fly ash in step S1 is 60:40 to 40:60.

[0012] As an improvement, the amount of calcium hydroxide added in step S2 is 5-8% of the weight of the mixed powder.

[0013] As an improvement, the composite alkali-activated catalyst in step S2 includes sodium silicate, zinc oxide and titanium dioxide.

[0014] As an improvement, the addition amount of each raw material in the composite alkali-activated catalyst in step S2 is: sodium silicate 0.8-1.2%, zinc oxide 0.15-0.3%, titanium dioxide 0.05-0.2%.

[0015] As an improvement, the curing conditions in step S4 are: at 20-30°C and 90-96% relative humidity, the curing time is 28-30 days

[0016] The technical advantages of the present invention are:

[0017] 1. The present invention effectively reduces the environmental pollution caused by coal gangue and fly ash by converting them into high-performance building materials, and at the same time realizes the recycling of resources. This method not only reduces the exploitation of natural resources, but also reduces the environmental pressure of solid waste treatment, and promotes the green development of the building materials industry.

[0018] 2. The building materials prepared by the method of the present invention have excellent mechanical properties and durability, meeting or even exceeding the standard requirements of the construction industry. At the same time, since low-cost solid waste is used as raw materials, the production cost is greatly reduced, the economic benefit is improved, and the building materials are more economical.

[0019] 3. The present invention uses a composite alkali-activated catalyst, including sodium silicate, zinc oxide and titanium dioxide. The catalyst of the present invention has a synergistic effect and can significantly increase the activity of coal-based solid waste, thereby improving the performance of the final product. DETAILED DESCRIPTION

[0020] The present invention is described in detail and specifically by specific examples below to provide a better understanding of the present invention, but the following examples do not limit the protection scope of the present invention.

[0021] Example 1

[0022] This embodiment discloses a method for preparing high-performance building materials from coal-based solid waste, comprising the following steps:

[0023] S1. Collect coal gangue and fly ash, and obtain fine powder with a particle size of less than 5 mm after crushing, screening and drying, wherein the ratio of coal gangue to fly ash is 1:1.

[0024] S2. Mix the fine powder with 5% calcium hydroxide, and add a composite alkali-activated catalyst consisting of 1% sodium silicate, 0.2% zinc oxide and 0.1% titanium dioxide. After stirring evenly, leave it for 24 hours to activate the activity.

[0025] S3. Mix the activated coal-based solid waste with cement and aggregate in a ratio of 40:35:25 and stir evenly.

[0026] S4. Press the mixture into shapes, such as standard bricks, and then cure at 20°C and 95% relative humidity for 28 days.

[0027] Performance tests were carried out on the cured bricks, and the test results showed that their compressive strength reached 35MPa and their flexural strength reached 7MPa, which met the standards of the construction industry.

[0028] Example 2

[0029] This embodiment discloses a method for preparing high-performance building materials from coal-based solid waste, comprising the following steps:

[0030] S1. Collect coal gangue and fly ash, and obtain fine powder with a particle size of less than 5 mm after crushing, screening and drying, wherein the ratio of coal gangue to fly ash is 40:60.

[0031] S2. Mix the fine powder with 5% calcium hydroxide, and add a composite alkali-activated catalyst consisting of 0.8% sodium silicate, 0.3% zinc oxide and 0.2% titanium dioxide, stir evenly, and leave it for 24 hours to activate the activity.

[0032] S3. Mix the activated coal-based solid waste with cement and aggregate in a ratio of 50:30:20 and stir evenly.

[0033] S4. Press the mixture into shapes, such as standard bricks, and then cure at 20°C and 95% relative humidity for 30 days.

[0034] Performance tests were carried out on the cured bricks, and the test results showed that their compressive strength reached 40MPa and their flexural strength reached 8MPa, which met the standards of the construction industry.

[0035] Example 3

[0036] This embodiment discloses a method for preparing high-performance building materials from coal-based solid waste, comprising the following steps:

[0037] S1. Collect coal gangue and fly ash, and obtain fine powder with a particle size of less than 5 mm after crushing, screening and drying, wherein the ratio of coal gangue to fly ash is 60:40.

[0038] S2. Mix the fine powder with 5% calcium hydroxide, and add a composite alkali-activated catalyst consisting of 1.2% sodium silicate, 0.15% zinc oxide and 0.05% titanium dioxide. After stirring evenly, leave it for 24 hours to activate the activity.

[0039] S3. Mix the activated coal-based solid waste with cement and aggregate in a ratio of 60:20:20 and stir evenly.

[0040] S4. Press the mixture into shapes, such as standard bricks, and then cure at 20°C and 95% relative humidity for 30 days.

[0041] Performance tests were carried out on the cured bricks, and the test results showed that their compressive strength reached 36MPa and their flexural strength reached 8MPa, which met the standards of the construction industry.

[0042] The specific embodiments of the present invention are described in detail above, but they are only examples, and the present invention is not equivalent to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions made to the present invention are also within the scope of the present invention. Therefore, the equalization changes and modifications made without departing from the spirit and scope of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing high-performance building materials from coal-based solid waste, characterized in that: The steps include: S1. Collect coal gangue and fly ash, crush, screen and dry them respectively, and then mix them evenly according to the proportion; S2. The mixed powder obtained in S1 is mixed with calcium hydroxide, and a composite base is added to activate the catalyst, stirred evenly, and allowed to stand to activate the activity; S3. Mix the excited coal-based solid waste with cement and aggregate in proportion and stir evenly; S4. Pressing the mixture into a shape and then curing it.

2. The method for preparing high-performance building materials from coal-based solid waste according to claim 1, characterized in that: In step S1, the ratio of coal gangue to fly ash is 60:40 to 40:

60.

3. The method for preparing high-performance building materials from coal-based solid waste according to claim 1, characterized in that: The amount of calcium hydroxide added in step S2 is 5-8% of the weight of the mixed powder.

4. The method for preparing high-performance building materials from coal-based solid waste according to claim 1, characterized in that: The composite alkali-activated catalyst in step S2 includes sodium silicate, zinc oxide and titanium dioxide.

5. The method for preparing high-performance building materials from coal-based solid waste according to claim 4, characterized in that: In step S2, the addition amount of each raw material in the composite alkali-activated catalyst is: 0.8-1.2% sodium silicate, 0.15-0.3% zinc oxide, and 0.05-0.2% titanium dioxide.

6. The method for preparing high-performance building materials from coal-based solid waste according to claim 1, characterized in that: The curing conditions in step S4 are: at 20-30° C. and 90-96% relative humidity, and the curing time is 28-30 days.

7. The method for preparing high-performance building materials from coal-based solid waste according to claim 1, characterized in that: In step S1, the raw material is crushed to a particle size less than 5 mm.