Coal gangue ecological slope protection brick and preparation method thereof

Abstract

The invention discloses a coal gangue ecological slope protection brick and a preparation method thereof, and belongs to the technical field of coal gangue bricking.The slope protection brick is prepared from coal gangue, ammonium formate, eugenol, sodium oleate, methyl p-hydroxybenzoate, clay, fly ash and the like, the coal gangue is pretreated and then mixed with the clay and other raw materials to be pressed into a green brick, and then the green brick is fired; according to the present invention, the coal gangue is adopted as the main raw material to prepare the slope protection brick, such that the strength and the anti-aging performance of the finished product brick are improved, the problem that the use performance is reduced due to insufficient strength and poor anti-aging performance of the coal gangue slope protection brick prepared by using the conventional method is solved, and the important significance is provided for promoting the resource utilization of the coal gangue.

Description

Technical Field

[0001] The invention relates to the technical field of coal gangue brick making, in particular to a coal gangue ecological slope protection brick and a preparation method thereof. Background Art

[0002] With the continuous acceleration of urbanization, the market demand for slope protection bricks as an important building material is increasing. In urban infrastructure construction, ecological restoration, flood prevention and disaster relief, slope protection bricks play an indispensable role.

[0003] Slope protection bricks include asphalt concrete slope protection bricks, concrete slope protection bricks, ecological slope protection bricks, etc. Asphalt concrete slope protection bricks have the advantages of good frost resistance, strong water resistance and low cost, but poor strength and durability, and are suitable for occasions where slope protection requirements are not too high; concrete slope protection bricks have high strength, good frost resistance and low cost, but traditional concrete bricks have poor air permeability and are not conducive to plant growth; compared with concrete slope protection bricks and asphalt concrete slope protection bricks, ecological slope protection bricks are widely used in ecological slope protection projects because of their excellent air permeability, strong frost resistance and beneficial to plant growth. In today's green development, they have good development and application prospects.

[0004] Gangue is solid waste generated during coal mining. Using it as the raw material for ecological slope protection bricks can reduce environmental pollution and effectively utilize resources. The ecological slope protection bricks prepared with gangue as raw material have good water permeability, water retention and corrosion resistance, and have good application prospects. However, most of the gangue slope protection bricks prepared by conventional methods have poor mechanical strength and weak anti-aging performance, which reduces the performance of the gangue ecological slope protection bricks. Summary of the invention

[0005] Based on the above technical problems, the purpose of the present invention is to provide a coal gangue ecological slope protection brick and a preparation method thereof, to prepare an ecological slope protection brick with high strength and good anti-aging performance using coal gangue as the main raw material, to improve the slope protection performance of coal gangue slope protection bricks, and at the same time promote the resource utilization of coal gangue.

[0006] The present invention solves the above technical problems by the following technical means:

[0007] A coal gangue ecological slope protection brick, the slope protection brick comprises the following raw materials in parts by weight:

[0008] 250-350 parts of coal gangue, 2-6 parts of ammonium formate, 3-10 parts of eugenol, 3-7 parts of sodium oleate, 1-6 parts of methyl p-hydroxybenzoate, 15-30 parts of clay, and 10-25 parts of fly ash.

[0009] Furthermore, the slope protection bricks include the following raw materials in parts by weight:

[0010] 290-310 parts of coal gangue, 3-5 parts of ammonium formate, 6-8 parts of eugenol, 4-6 parts of sodium oleate, 3-4 parts of methyl p-hydroxybenzoate, 20-26 parts of clay, and 15-20 parts of fly ash.

[0011] Furthermore, the slope protection bricks include the following raw materials in parts by weight:

[0012] 300 parts of coal gangue, 4 parts of ammonium formate, 7 parts of eugenol, 5 parts of sodium oleate, 4 parts of methyl p-hydroxybenzoate, 25 parts of clay and 16 parts of fly ash.

[0013] The present invention also discloses a preparation method of the ecological slope protection brick, and the preparation method is as follows:

[0014] (1) Putting the coal gangue raw material into a pulverizer for pulverization and then passing through a 40-100 mesh sieve to obtain refined coal gangue;

[0015] (2) putting the refined coal gangue into a reactor, injecting water, adding ammonium formate, stirring and mixing well, and then standing overnight; then dissolving eugenol in an ethanol solution with a volume fraction of 75% and adding it for heating reaction, filtering and removing the filtrate after the reaction is completed, and placing it in a furnace, heating it to 150° C. at a heating rate of 30-50° C. / h, keeping it warm for 1-2 hours, and then heating it to 250° C. at a heating rate of 30-50° C. / h, keeping it warm for 30-60 minutes, and then cooling it to room temperature, and standing it at room temperature for aging for 12-24 hours to obtain pretreated coal gangue;

[0016] (3) adding water to the pretreated coal gangue and clay and mixing them evenly, then adding fly ash, sodium oleate, and methyl parahydroxybenzoate in sequence and mixing them evenly, and letting them stand for 12-24 hours to obtain a mixture;

[0017] (4) placing the mixture into a mold for pressing and then drying to obtain a brick;

[0018] (5) The bricks are placed in a furnace for high-temperature firing to obtain slope protection bricks.

[0019] The reaction activity of the components in the gangue is improved by crushing and screening the gangue, putting it into water and adding ammonium formate for treatment, and then eugenol is added for heating reaction. After the reaction is completed, variable temperature heat treatment and static aging are performed to obtain pretreated gangue. Eugenol reacts and combines with molecules in the gangue to change the chemical properties of the gangue molecules and increase the mutual binding force between the molecules in the gangue. In the subsequent brick-making process, the gangue molecules can be tightly combined, thereby improving the density of the prepared brick body, thereby increasing the strength of the brick body and improving its slope protection performance.

[0020] Then, sodium oleate and methyl parahydroxybenzoate are added to the pretreated coal gangue and other materials, and the mixture is allowed to stand for static treatment to obtain a mixture, which is then pressed into blanks. Sodium oleate and methyl parahydroxybenzoate are interspersed in the microporous structure formed by the coal gangue particles and firmly adhere to the surface thereof, inhibiting the absorption of water molecules by the coal gangue and hindering the entry of water molecules, thereby improving the water resistance of the slope protection bricks, while blocking the erosion of the slope protection bricks by ultraviolet rays and harmful ions, thereby improving the anti-aging performance of the prepared slope protection bricks.

[0021] Furthermore, in step (2), the reaction temperature is heated to 55-75° C. and the reaction time is 2-4 h.

[0022] Furthermore, the amount of water added in step (3) is 15-25% of the weight of the mixture of coal gangue and clay, and the pH of the water needs to be adjusted to 4-5 before adding.

[0023] Furthermore, the drying temperature in step (4) is 80-100°C.

[0024] Furthermore, the high temperature firing operation in step (5) is as follows: gradually raising the temperature to 800°C at a rate of 10-20°C / min, keeping the temperature for 1 hour, then gradually raising the temperature to 1100°C at a rate of 5-10°C / min, keeping the temperature for 1 hour, and then cooling with the furnace to obtain the slope protection bricks.

[0025] Furthermore, the slope protection bricks are in any shape of a quadrangular prism, a pentagonal prism, a hexagonal prism, a cube, or a cuboid.

[0026] Furthermore, preferably, the slope protection bricks are in the shape of hexagonal prisms.

[0027] Beneficial effects:

[0028] 1. The present invention uses coal gangue, a solid waste generated by coal mining, as the main raw material to prepare slope protection bricks, which can not only better meet the high demand for slope protection bricks in my country's infrastructure construction, but also promote the resource utilization of coal gangue, and effectively promote the protection of the ecological environment.

[0029] 2. The present invention can effectively increase the strength of the prepared brick and improve its anti-aging performance by pre-treating the coal gangue and mixing it with raw materials such as clay and sodium oleate, and then pressing and sintering at high temperature.

[0030] 3. The present invention preferentially prepares the brick body into hexagonal bricks, and more bricks can be prepared with the same raw materials. After the brick bodies are laid, they fit tightly to each other, which can effectively improve the anti-slip performance, and cultivated plants can be planted in the middle position, which has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 : is the picture of coal gangue, the main raw material of brick making of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings:

[0033] Example 1: Preparation of slope protection bricks

[0034] Weigh 300 kg of coal gangue, 4 kg of ammonium formate, 7 kg of eugenol, 5 kg of sodium oleate, 4 kg of methyl parahydroxybenzoate, 25 kg of clay, and 16 kg of fly ash.

[0035] Preparation method:

[0036] (1) putting the coal gangue raw material into a pulverizer for pulverization and passing through a 50-mesh sieve to obtain refined coal gangue;

[0037] (2) Put the refined coal gangue into a reactor, inject water to cover the coal gangue, add ammonium formate, stir and mix thoroughly, and then stand overnight; then dissolve eugenol in 14 kg of 75% ethanol solution and add it, and heat it at 65°C for 3 hours; after the reaction is completed, filter and remove the filtrate and put it in a furnace, heat it to 150°C at a heating rate of 40°C / h, keep it warm for 1.5 hours, then heat it to 250°C at a heating rate of 40°C / h, keep it warm for 40 minutes, cool it to room temperature, and stand it at room temperature for 16 hours to obtain pretreated coal gangue;

[0038] (3) Mix the pretreated gangue and clay evenly, take 20% of the weight of the mixed coal gangue and clay water, adjust the pH to 4.5, add to the pretreated coal gangue and clay mixture and mix evenly, then add fly ash, sodium oleate, and methyl parahydroxybenzoate in sequence and mix evenly, and let stand for 16 hours to obtain a mixture;

[0039] (4) placing the mixture into a mold and pressing it into a hexagonal column shape, and then drying it at 90° C. until the moisture content is less than 1% to obtain a brick;

[0040] (5) The bricks were placed in a furnace and the temperature was gradually raised to 800°C at a rate of 15°C / min, kept at that temperature for 1 h, and then gradually raised to 1100°C at a rate of 6°C / min. After keeping at that temperature for 1 h, the bricks were cooled in the furnace to obtain slope protection bricks.

[0041] Example 2: Preparation of slope protection bricks

[0042] Weigh 290 kg of coal gangue, 3 kg of ammonium formate, 6 kg of eugenol, 4 kg of sodium oleate, 3 kg of methyl parahydroxybenzoate, 20 kg of clay, and 15 kg of fly ash.

[0043] Preparation method:

[0044] (1) putting the coal gangue raw material into a pulverizer for pulverization and passing through a 40-mesh sieve to obtain refined coal gangue;

[0045] (2) Put the refined coal gangue into a reactor, inject water to cover the coal gangue, add ammonium formate, stir and mix thoroughly, and then stand overnight; then dissolve eugenol in 12kg of 75% ethanol solution and add it, and heat it at 55°C for 3.5h; after the reaction is completed, filter and remove the filtrate and put it in a furnace, heat it to 150°C at a heating rate of 30°C / h, keep it warm for 1h, then heat it to 250°C at a heating rate of 30°C / h, keep it warm for 35min, cool it to room temperature, and stand it at room temperature for 13h to obtain pretreated coal gangue;

[0046] (3) Mix the pretreated coal gangue and clay evenly, take 15% of the weight of the mixed coal gangue and clay water, adjust the pH to 4.5, add to the pretreated coal gangue and clay mixture and mix evenly, then add fly ash, sodium oleate, and methyl parahydroxybenzoate in sequence and mix evenly, and let stand for 12 hours to obtain a mixture;

[0047] (4) placing the mixture into a mold and pressing it into a hexagonal column shape, and then drying it at 85° C. until the moisture content is less than 1% to obtain a brick;

[0048] (5) The bricks were placed in a furnace and the temperature was gradually raised to 800°C at a rate of 10°C / min and kept at that temperature for 1 h. The temperature was then gradually raised to 1100°C at a rate of 5°C / min and kept at that temperature for 1 h before being cooled in the furnace to obtain slope protection bricks.

[0049] Example 3: Preparation of slope protection bricks

[0050] Weigh 310 kg of coal gangue, 5 kg of ammonium formate, 8 kg of eugenol, 6 kg of sodium oleate, 4 kg of methyl parahydroxybenzoate, 26 kg of clay, and 20 kg of fly ash.

[0051] Preparation method:

[0052] (1) putting the coal gangue into a pulverizer for pulverization and passing through a 60-mesh sieve to obtain refined coal gangue;

[0053] (2) Put the refined coal gangue into a reactor, inject water to cover the coal gangue, add ammonium formate, stir and mix thoroughly, and then stand overnight; then dissolve eugenol in 16 kg of 75% ethanol solution and add it, and heat it at 75°C for 2 hours; after the reaction is completed, filter and remove the filtrate and put it in a furnace, heat it to 150°C at a heating rate of 50°C / h, keep it warm for 2 hours, then heat it to 250°C at a heating rate of 50°C / h, keep it warm for 60 minutes, cool it to room temperature, and stand it at room temperature for 24 hours to obtain pretreated coal gangue;

[0054] (3) mixing the pretreated gangue and clay evenly, taking clean water which is 25% of the weight of the mixture of gangue and clay, adjusting the pH to 4.6, adding the water to the mixture of gangue and clay evenly, and then adding fly ash, sodium oleate, and methyl paraben in sequence to mix evenly to obtain a mixture;

[0055] (4) placing the mixture into a mold and pressing it into a hexagonal column shape, and then drying it at 95° C. until the moisture content is less than 1% to obtain a brick;

[0056] (5) The bricks were placed in a furnace and the temperature was gradually raised to 800°C at a rate of 15°C / min and kept at that temperature for 1 h. The temperature was then gradually raised to 1100°C at a rate of 7°C / min and kept at that temperature for 1 h before being cooled in the furnace to obtain slope protection bricks.

[0057] Comparative Example 1: Preparation of slope protection bricks

[0058] In contrast to Example 1, the only difference is that no ammonium formate is added for treatment during the preparation of the slope protection bricks in Comparative Example 1, as follows:

[0059] (1) Same as Example 1;

[0060] (2) Put the refined coal gangue into a reactor, inject water to cover the coal gangue and let it stand overnight; then dissolve eugenol in 14 kg of 75% ethanol solution and add it, and heat it at 65° C. for 3 hours; after the reaction is completed, filter and remove the filtrate and put it in a furnace, heat it to 150° C. at a heating rate of 40° C. / h, keep it warm for 1.5 hours, then heat it to 250° C. at a heating rate of 40° C. / h, keep it warm for 40 minutes, cool it to room temperature, and let it stand at room temperature for 16 hours to obtain pretreated coal gangue;

[0061] (3)-(5) are the same as in Example 1.

[0062] Comparative Example 2: Preparation of slope protection bricks

[0063] In contrast to Example 1, the only difference is that in Comparative Example 2, no eugenol is added for treatment during the preparation of the slope protection bricks, as follows:

[0064] (1) Same as Example 1;

[0065] (2) Put the refined coal gangue into a reactor, inject water to cover the coal gangue, add ammonium formate, stir and mix thoroughly, and then stand overnight; then filter to remove the filtrate and put it into a furnace, heat it to 150°C at a heating rate of 40°C / h, keep it warm for 1.5h, then heat it to 250°C at a heating rate of 40°C / h, keep it warm for 40min, cool it to room temperature, and stand it at room temperature for 16h to obtain pretreated coal gangue;

[0066] (3)-(5) are the same as in Example 1.

[0067] Comparative Example 3: Preparation of slope protection bricks

[0068] In contrast to Example 1, the only difference is that sodium oleate is not added when preparing the slope protection bricks in Comparative Example 3, as follows:

[0069] (1)-(2) are the same as in Example 1;

[0070] (3) Mix the pretreated gangue and clay evenly, take 20% of the weight of the mixed gangue and clay water, adjust the pH to 4.5, add to the pretreated gangue and clay mixture and mix evenly, then add fly ash and methyl paraben in sequence and mix evenly, and let stand for 16 hours to obtain a mixture;

[0071] (4)-(5) are the same as in Example 1.

[0072] Comparative Example 4: Preparation of slope protection bricks

[0073] In contrast to Example 1, the only difference is that methyl paraben is not added during the preparation of the slope protection bricks in Comparative Example 4, as follows:

[0074] (1)-(2) are the same as in Example 1;

[0075] (3) Mix the pretreated gangue and clay evenly, take 20% of the weight of the mixed coal gangue and clay water, adjust the pH to 4.5, add to the pretreated coal gangue and clay mixture and mix evenly, then add fly ash and sodium oleate in sequence and mix evenly, and let stand for 16 hours to obtain a mixture;

[0076] (4)-(5) are the same as in Example 1.

[0077] Comparative Example 5: Preparation of slope protection bricks

[0078] In contrast to Example 1, the only difference is that in the preparation of the slope protection bricks in Comparative Example 5, the reaction is carried out at room temperature (26° C.), as follows:

[0079] (1) Same as Example 1;

[0080] (2) Put the refined coal gangue into a reactor, inject water to cover the coal gangue, add ammonium formate, stir and mix thoroughly, and then stand overnight; then dissolve eugenol in 14 kg of 75% ethanol solution and add it, and react at 26°C for 3 hours; after the reaction is completed, filter and remove the filtrate and put it in a furnace, heat it to 150°C at a heating rate of 40°C / h, keep it warm for 1.5 hours, then heat it to 250°C at a heating rate of 40°C / h, keep it warm for 40 minutes, cool it to room temperature, and stand it at room temperature for 16 hours to obtain pretreated coal gangue;

[0081] (3)-(5) are the same as in Example 1.

[0082] Comparative Example 6: Preparation of slope protection bricks

[0083] In contrast to Example 1, the only difference is that the heating reaction temperature in step (2) during the preparation of the slope protection bricks in Comparative Example 6 is 90° C., as follows:

[0084] (1) Same as Example 1;

[0085] (2) Put the refined coal gangue into a reactor, inject water to cover the coal gangue, add ammonium formate, stir and mix thoroughly, and then stand overnight; then dissolve eugenol in 14 kg of 75% ethanol solution and add it, and heat it at 90°C for 3 hours; after the reaction is completed, filter and remove the filtrate and put it in a furnace, heat it to 150°C at a heating rate of 40°C / h, keep it warm for 1.5 hours, then heat it to 250°C at a heating rate of 40°C / h, keep it warm for 40 minutes, cool it to room temperature, and stand it at room temperature for 16 hours to obtain pretreated coal gangue;

[0086] (3)-(5) are the same as in Example 1.

[0087] Comparative Example 7: Preparation of slope protection bricks

[0088] In contrast to Example 1, the only difference is that in the preparation of slope protection bricks in Comparative Example 7, the temperature is directly raised to 250° C. and kept warm for 1.5 h in step (2), as follows:

[0089] (1) Same as Example 1;

[0090] (2) Put the refined coal gangue into a reactor, inject water to cover the coal gangue, add ammonium formate, stir and mix thoroughly, and then stand overnight; then dissolve eugenol in 14 kg of 75% ethanol solution and add it, and heat it at 65° C. for 3 hours; after the reaction is completed, filter and remove the filtrate and put it in a furnace, heat it to 250° C. at a heating rate of 40° C. / h, keep it warm for 1.5 hours, cool it to room temperature, and stand it at room temperature for 16 hours to obtain pretreated coal gangue;

[0091] (3)-(5) are the same as in Example 1.

[0092] Comparative Example 8: Preparation of slope protection bricks

[0093] In contrast to Example 1, the only difference is that in the preparation of the slope protection bricks in Comparative Example 8, the slope protection bricks are not placed in a furnace for variable temperature heat treatment in step (2), as follows:

[0094] (1) Same as Example 1;

[0095] (2) putting the refined coal gangue into a reactor, injecting water to cover the coal gangue, adding ammonium formate, stirring and mixing thoroughly, and then standing overnight; then dissolving eugenol in 14 kg of 75% ethanol solution by volume and adding it, heating at 65° C. for 3 hours; after the reaction is completed, filtering and removing the filtrate to obtain pretreated coal gangue;

[0096] (3)-(5) are the same as in Example 1.

[0097] Comparative Example 9: Preparation of slope protection bricks

[0098] In contrast to Example 1, the only difference is that in step (3) of preparing the slope protection bricks in Comparative Example 9, the pH of water is adjusted to 3, and the remaining steps are the same as in Example 1.

[0099] Comparative Example 10: Preparation of slope protection bricks

[0100] In contrast to Example 1, the only difference is that in step (3) of preparing the slope protection bricks in Comparative Example 10, the pH of water is adjusted to 6, and the remaining steps are the same as in Example 1.

[0101] Experiment: Slope protection brick performance test experiment

[0102] The compressive strength and 24h water absorption (water resistance) of the slope protection bricks prepared in Examples 1-3 and Comparative Examples 1-10 were tested, and the data obtained are shown in Table 1.

[0103] Table 1

[0104]

[0105]

[0106] According to the data analysis in Table 1:

[0107] (1) The slope protection bricks prepared in Examples 1-3 have high compressive strength, all greater than 11Mpa, indicating that the coal gangue slope protection bricks prepared by the present invention have good slope protection performance; and the 24h water absorption rate is low, indicating that it has good water resistance, and thus has good durability and stability in practical applications, and has good application prospects. In addition, the slope protection bricks prepared by the present invention are mainly made of coal gangue as raw material, which not only promotes the resource utilization of coal gangue, but also has important significance for the protection of the ecological environment.

[0108] (2) In comparative example 1, ammonium formate was not added during the preparation of the slope protection bricks, and the subsequent reaction activity between the coal gangue and other raw materials was poor, which in turn affected the overall performance of the prepared brick body; in comparative example 2, eugenol was not added during the preparation of the slope protection bricks, and the bonding ability between the molecules in the coal gangue was poor, resulting in a higher density of the prepared brick body, which reduced the compressive strength of the brick and increased its water absorption.

[0109] (3) In comparative example 3, sodium oleate was not added during the preparation of the slope protection bricks, and in comparative example 4, methyl paraben was not added during the preparation of the slope protection bricks. The absorption capacity of the gangue particles for water molecules could not be better suppressed, and the 24h water absorption rate increased to varying degrees, and the water resistance was poor.

[0110] (4) In comparative example 7, the furnace heat treatment conditions in step (2) were changed during the preparation of the slope protection bricks; in comparative example 8, the variable temperature heat treatment was not performed in step (2) during the preparation of the slope protection bricks; in comparative examples 9 and 10, the pH of the added water was changed, and the performance of the slope protection bricks prepared uniformly decreased to varying degrees, among which the performance of comparative example 8 decreased the most, indicating that the heat treatment in step (2) plays a relatively important role in jointly improving the performance of the prepared slope protection bricks.

[0111] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention. The techniques, shapes, and structural parts not described in detail in the present invention are all known technologies.

Claims

1. A coal gangue ecological slope protection brick, characterized in that: The slope protection bricks include the following raw materials by weight: 250-350 parts of coal gangue, 2-6 parts of ammonium formate, 3-10 parts of eugenol, 3-7 parts of sodium oleate, 1-6 parts of methyl p-hydroxybenzoate, 15-30 parts of clay, and 10-25 parts of fly ash.

2. The coal gangue ecological slope protection brick according to claim 1, characterized in that: The slope protection bricks include the following raw materials by weight: 290-310 parts of coal gangue, 3-5 parts of ammonium formate, 6-8 parts of eugenol, 4-6 parts of sodium oleate, 3-4 parts of methyl p-hydroxybenzoate, 20-26 parts of clay, and 15-20 parts of fly ash.

3. The coal gangue ecological slope protection brick according to claim 2, characterized in that: The slope protection bricks include the following raw materials by weight: 300 parts of coal gangue, 4 parts of ammonium formate, 7 parts of eugenol, 5 parts of sodium oleate, 4 parts of methyl p-hydroxybenzoate, 25 parts of clay and 16 parts of fly ash.

4. A method for preparing coal gangue ecological slope protection bricks, characterized in that: The preparation method is as follows: (1) Put the coal gangue into a crusher and crush it, and pass it through a 40-100 mesh sieve to obtain fine coal gangue; (2) Put the refined coal gangue into a reactor, inject water, add ammonium formate, stir and mix evenly, and then stand overnight; then dissolve eugenol in ethanol and add it for heating reaction. After the reaction is completed, filter and remove the filtrate and put it in a furnace, heat it to 150°C at a heating rate of 30-50°C / h, keep it warm for 1-2h, then heat it to 250°C at a heating rate of 30-50°C / h, keep it warm for 30-60min, cool it to room temperature, and stand it at room temperature for aging for 12-24h to obtain pretreated coal gangue; (3) adding water to the pretreated coal gangue and clay and mixing them evenly, then adding fly ash, sodium oleate, and methyl parahydroxybenzoate in sequence and mixing them evenly, and letting them stand for 12-24 hours to obtain a mixture; (4) placing the mixture into a mold for pressing and then drying to obtain a brick; (5) The bricks are placed in a furnace and fired at high temperature to obtain slope protection bricks.

5. The method for preparing a coal gangue ecological slope protection brick according to claim 4, characterized in that: In the step (2), the heating reaction temperature is 55-75° C. and the heating reaction time is 2-4 h.

6. The method for preparing the coal gangue ecological slope protection brick according to claim 5, characterized in that: The amount of water added in step (3) is 15-25% of the weight of the mixture of coal gangue and clay. When adding water, the pH of the water needs to be adjusted to 4-5.

7. The method for preparing the coal gangue ecological slope protection brick according to claim 6, characterized in that: The drying temperature in step (4) is 80-100°C.

8. The method for preparing the coal gangue ecological slope protection brick according to claim 7, characterized in that: The high temperature firing operation in step (5) is as follows: the temperature is raised to 800°C at a rate of 10-20°C / min, kept at that temperature for 1 hour, then raised to 1100°C at a rate of 5-10°C / min, kept at that temperature for 1 hour, and then cooled in the furnace to obtain the slope protection bricks.

9. The method for preparing the coal gangue ecological slope protection brick according to claim 8, characterized in that: The shape of the slope protection brick is any one of a quadrangular prism, a pentagonal prism, a hexagonal prism, a cube and a cuboid.

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