Preparation method and formula of coal-based solid waste artificial soil

Abstract

The invention discloses a preparation method and a formula of coal-based solid waste artificial soil. The preparation method comprises the following steps: step A; the preparation method comprises the following steps: processing coal gangue, fly ash, carbide slag and desulfurized gypsum to form powder with uniform particle size, and then carrying out fluidized calcination; step B; the calcined coal gangue powder and prefabricated multi-component self-setting powder are proportionally mixed to form a mixture, and the mixture and water are mixed to prepare slurry; step C; adding a foaming agent into the slurry, introducing into a mold after foaming, and curing at constant temperature to form a solid test block; according to the method, coal gangue powder is innovatively adopted as a core raw material, self-solidifying powder with coal-based solid waste as a main body is combined to serve as a gelling agent, an aluminum powder foaming agent is supplemented, the coal gangue-based artificial soil is elaborately developed, the novel soil inherits the basic functions of natural soil, and the novel soil is excellent in water retention, loss resistance and heat preservation performance; and an ideal soil alternative scheme is provided for ecological restoration of a mining area.

Description

Technical Field

[0001] The present invention specifically relates to a preparation method and formula of coal-based solid waste artificial soil. Background Art

[0002] As the cornerstone of stable energy supply, coal is mainly mined by underground shaft mining. However, when mining in high water table areas, this method is prone to the formation of goafs, leading to surface subsidence and water accumulation, seriously eroding arable land resources. At the same time, the accumulation of solid waste such as coal gangue not only occupies a large amount of land, but also poses potential threats of debris flow and air pollution.

[0003] The existing ecological restoration of coal mining areas mostly relies on imported soil from other places. However, this approach is limited by the scarcity of soil resources, and it performs poorly in aspects such as soil fertility preservation and anti-water and soil loss, and may even increase the ecological burden of the mining area. In contrast, although the direct backfilling repair method of coal gangue, as a rich solid waste resource in the mining area, has been tried, the effect is not satisfactory and there are many limitations. Therefore, we propose a preparation method and formula of coal-based solid waste artificial soil. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and formula of coal-based solid waste artificial soil to solve the problems of poor soil repair effect by directly using coal gangue and inconvenient recycling of coal gangue mentioned in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A preparation method of coal-based solid waste artificial soil, including the following steps:

[0006] Step A: Process coal gangue, fly ash, carbide slag and desulfurized gypsum to form uniformly sized powder, and then perform fluidized calcination;

[0007] Step B: Mix the calcined coal gangue powder with a prefabricated multi-component self-setting powder to form a mixture, and mix the mixture with water to prepare a slurry;

[0008] Step C: Add a foaming agent to the slurry, foam it and then introduce it into a mold, and perform constant temperature curing to form a solid test block;

[0009] Step D: After curing, take out the solidified test block from the mold and dry it;

[0010] Step E: Crush the dried test block, and then screen it into uniformly sized particles, which are the coal-based solid waste artificial soil.

[0011] Preferably, when processing in Step A, first perform crushing, then grinding, and screen to form uniformly sized powder through screening, and the screening size is 100 - 200 mesh during screening.

[0012] Preferably, when performing fluidized calcination in step A, pulverized coal gangue, fly ash, carbide slag and desulfurized gypsum are added to a quartz fluidized bed reactor, and air is introduced for fluidized calcination at a temperature of 500-800°C.

[0013] Preferably, in step B, the ratio of the multi-component self-setting powder is fly ash: carbide slag: desulfurized gypsum = 15:4:1.

[0014] Preferably, when preparing the slurry in step B, water is added to a beaker and placed under a high-speed disperser. The machine speed is adjusted to 700-900 revolutions per minute, and the mixture is added to the water at a constant speed and rapidly stirred by the disperser.

[0015] Preferably, the foaming agent in step C is aluminum powder. During constant temperature curing, the uniformly stirred slurry is poured into a mold, and the mold is placed in a constant temperature curing box for 9-15 hours of constant temperature curing.

[0016] Preferably, when drying in step D, the test block is taken out of the mold and dried in a forced air drying oven at 105°C for 20-28 hours.

[0017] Preferably, in step E: the dried test block is crushed using a jaw crusher, and then screened using an electric sieve to ensure that the particle size of the final particles is less than 5 mm.

[0018] A formula for a coal-based solid waste artificial soil, comprising the following raw materials in parts by weight:

[0019] 85-90 parts of pulverized coal gangue;

[0020] 10-15 parts of multi-component self-setting powder;

[0021] A foaming agent, accounting for 0.5 parts of the total weight of the raw materials.

[0022] Preferably, the multi-component self-setting powder includes fly ash, carbide slag and desulfurized gypsum, and the weight ratio of fly ash: carbide slag: desulfurized gypsum is 15:4:1.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] Through the preparation method of the present invention, the problem of coal gangue accumulation can be fundamentally solved. At the same time, the damaged ecological environment soil foundation can be rebuilt, enabling the coal mining area to regain vitality and achieving a win-win situation of economic and ecological benefits. This method innovatively proposes using coal gangue powder as the core raw material, combining a self-setting powder mainly composed of coal-based solid waste as a gelling agent, and supplemented with an aluminum powder foaming agent to carefully develop a coal gangue-based artificial soil. This new type of soil not only inherits the basic functions of natural soil but also has excellent water retention, anti-erosion, and heat preservation properties, providing an ideal soil alternative for mine ecological restoration. Brief Description of the Drawings

[0025] Figure 1 It is a schematic flow chart of the preparation stage of the present invention;

[0026] Figure 2 It is a schematic flow chart of the reaction stage of the present invention. Detailed Embodiments

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] Please refer to Figure 1 , Figure 2 , the present invention provides a technical solution: a preparation method of a coal-based solid waste artificial soil, including the following steps:

[0029] Step A: Process coal gangue, fly ash, carbide slag, and desulfurized gypsum to form powders with uniform particle sizes, and then perform fluidized calcination;

[0030] Step B: Mix the calcined coal gangue powder with a pre-prepared multi-component self-setting powder to form a mixture, and mix the mixture with water to prepare a slurry, which is convenient for realizing the harmless treatment of coal-based solid waste through calcination. This process helps to convert harmful substances in the raw materials and ensure safe use;

[0031] Step C: Add a foaming agent to the slurry to improve porosity and air permeability through foaming. After foaming, introduce it into a mold and perform constant-temperature curing to form a solid test block;

[0032] Step D: After curing, take out the solidified test block from the mold and dry it;

[0033] Step E: Crush the dried test block, and then screen it into particles with uniform particle sizes, which are the coal-based solid waste artificial soil, facilitating the use of particles with uniform particle sizes.

[0034] Through this method, the coal-based solid waste is first harmlessly treated, and then the effective nutrients are activated and the structure is reconstructed. Finally, an artificial soil is generated, which exhibits excellent water retention and air permeability, and is rich in organic matter, trace nutrients, and nutrients such as nitrogen, phosphorus, and potassium that are essential for plant growth. It can be used as a viable alternative to natural soil and applied in the fields of soil improvement and ecological restoration. In addition, this method also has the ability to consume a large amount of industrial solid wastes such as coal gangue and fly ash, realizing the efficient recycling of resources.

[0035] Preferably, during the processing in step A, first perform crushing, then grinding after crushing, and form powders with uniform particle sizes through screening. When screening, screen to 100 - 200 mesh to ensure uniform particle sizes and facilitate the subsequent process.

[0036] Preferably, during the fluidized calcination in step A, add coal gangue powder, fly ash, carbide slag, and desulfurized gypsum into a quartz fluidized bed reactor, and at a temperature of 500 - 800 °C, introduce air for fluidized calcination to facilitate rapid calcination treatment and convert harmful substances into harmless substances for use.

[0037] Preferably, in step B, the ratio of the multi-component self-setting powder is fly ash: carbide slag: desulfurized gypsum = 15:4:1, which has good self-setting performance and is suitable for further making into soil materials.

[0038] Preferably, when preparing the slurry in step B, add water into a beaker and place it under a high-speed disperser. Adjust the machine speed to 700 - 900 revolutions per minute, add the mixture into the water evenly, and perform rapid stirring through the disperser to ensure that the mixture reacts fully with water to form a uniform slurry.

[0039] Preferably, the foaming agent in step C is aluminum powder. The addition of aluminum powder can trigger a reaction to generate gas, forming a foaming structure of the soil, increasing its looseness and air permeability. During the constant-temperature curing, pour the evenly stirred slurry into a mold, and place the mold in a constant-temperature curing box for 9 - 15 hours of constant-temperature curing to ensure that the chemical reaction in the slurry is complete and a stable solid structure is formed.

[0040] Preferably, during the drying in step D, take out the test block from the mold and dry it in a forced-air drying oven at 105 °C for 20 - 28 hours. This step helps to remove the moisture in the slurry, enabling the artificial soil to obtain sufficient hardness and stability.

[0041] Preferably, in step E: crush the dried test block using a jaw crusher, and then screen it using an electric sieve to ensure that the particle size of the final particles is less than 5 mm.

[0042] A formula for an artificial soil made from coal-based solid waste, comprising the following raw materials in parts by weight:

[0043] 85-90 parts of coal gangue powder;

[0044] Gangue is the waste from coal mining or coal washing, containing more non-coal minerals. Gangue powder, as the main ingredient, accounts for a large proportion in the formula, providing a good mineral basis and structural support. The addition of gangue powder can enhance the overall hardness and stability of artificial soil. At the same time, due to its rich silicate minerals, it can provide a certain fertilizer effect. The particles of gangue are relatively large, and after grinding, it can help improve the soil structure, permeability and water retention capacity.

[0045] 10-15 parts of multi-component self-curing powder;

[0046] Foaming agent, accounting for 0.5 parts by weight of the total raw materials.

[0047] The foaming agent accounts for a small proportion in the formula and is mainly used to improve the lightweight characteristics of the artificial soil. The role of the foaming agent is to produce bubbles, making the soil material lighter and more breathable, while improving water retention and fertilizer retention. The foaming agent produces bubbles during the processing process, trapping air inside the material, thereby reducing the weight of the final product and increasing the water retention and fertility of the soil.

[0048] Preferably, the multi-component self-condensing powder includes fly ash, carbide slag and desulfurized gypsum, and the weight ratio of fly ash: carbide slag: desulfurized gypsum is 15:4:1.

[0049] Fly ash, a fine dust emitted by coal-fired power plants, mainly contains silica, bauxite and iron oxide. Fly ash not only has good cementing properties, but also can improve the air permeability and structural stability of the soil; carbide slag: waste from the production process of calcium carbide, is a by-product containing a large amount of calcium oxide. It has strong alkalinity, which can improve the acidity of the soil and increase the stability of the soil; desulfurization gypsum: a by-product of the desulfurization process, contains a large amount of calcium and sulfur, which can be used as a regulator to improve the pH of the soil. At the same time, its own hydration properties also help to provide a stable consolidation effect. The weight ratio is 15:4:1. This ratio is designed to optimize the mixing performance of the material, which can not only ensure a certain cementing property, but also optimize the reaction performance of the material.

[0050] In view of this, this method innovatively proposes to use coal gangue powder as the core raw material, combine self-setting powder mainly composed of coal-based solid waste as a gelling agent, and supplement with aluminum powder foaming agent to carefully develop coal gangue-based artificial soil. This new type of soil not only inherits the basic functions of natural soil, but also demonstrates excellent performance in aspects such as water retention, anti-erosion, heat preservation, and fertilizer retention, providing an ideal soil alternative for mine ecological restoration. Through this method and formulation, it is convenient to fundamentally solve the problem of coal gangue accumulation, and at the same time rebuild the damaged ecological environment soil foundation, rejuvenate the coal mining area, and achieve a win-win situation of economic and ecological benefits.

[0051] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing coal-based solid waste artificial soil, characterized in that: The following steps are involved: Step A: processing coal gangue, fly ash, carbide slag and desulfurized gypsum to form a powder with uniform particle size, and then fluidizing and calcining; Step B: The calcined gangue powder is mixed with the prefabricated multi-component self-setting powder to form a mixture, and the mixture is mixed with water to form a slurry; Step C: adding a foaming agent into the slurry, introducing it into a mold after foaming, and curing it at a constant temperature to form a solid test block; Step D: After curing, the solidified test block is removed from the mold and dried; Step E: crushing the dried test block, and then sieving it into particles with uniform particle size, which is the coal-based solid waste artificial soil.

2. The method for preparing coal-based solid waste artificial soil according to claim 1, characterized in that: During the processing in step A, the powder is first crushed, then ground, and screened to form a powder with uniform particle size, wherein the screening is performed to 100-200 meshes.

3. The method for preparing coal-based solid waste artificial soil according to claim 1, characterized in that: When the fluidized calcination is performed in step A, coal gangue powder, fly ash, carbide slag and desulfurized gypsum are added into a quartz fluidized bed reactor, and air is introduced at a temperature of 500-800° C. for fluidized calcination.

4. The method for preparing coal-based solid waste artificial soil according to claim 1, characterized in that: In the step B, the ratio of the multi-component self-condensing powder is fly ash: carbide slag: desulfurized gypsum = 15:4:

1.

5. The method for preparing coal-based solid waste artificial soil according to claim 1, characterized in that: When preparing the slurry in step B, water is added to a beaker and placed under a rapid disperser. The machine speed is adjusted to 700-900 rpm, the mixture is uniformly added to the water, and the disperser is used for rapid stirring.

6. The method for preparing coal-based solid waste artificial soil according to claim 1, characterized in that: The foaming agent in step C is aluminum powder. During constant temperature curing, the evenly stirred slurry is poured into a mold, and the mold is placed in a constant temperature curing box for 9-15 hours of constant temperature curing.

7. The method for preparing coal-based solid waste artificial soil according to claim 1, characterized in that: During the drying step D, the test block is taken out from the mold and placed in a forced air drying oven at 105° C. for drying for 20-28 hours.

8. The method for preparing coal-based solid waste artificial soil according to claim 1, characterized in that: In the step E: the dried test block is crushed using a jaw crusher, and then screened using an electric sieve to ensure that the final particle size is less than 5 mm.

9. A formulation of coal-based solid waste artificial soil, characterized in that: The invention comprises the following raw materials in parts by weight: 85-90 parts of coal gangue powder; 10-15 parts of multi-component self-curing powder; Foaming agent, accounting for 0.5 parts by weight of the total raw materials.

10. The formula of the coal-based solid waste artificial soil according to claim 9, characterized in that: The multi-component self-condensing powder includes fly ash, carbide slag and desulfurized gypsum, and the weight ratio of the fly ash: carbide slag: desulfurized gypsum is 15:4:1.

Images