Soil conditioner prepared from waste and carbonaceous slate and preparation method of soil conditioner

Abstract

The invention discloses a soil conditioner prepared from waste and carbonaceous slate and a preparation method of the soil conditioner, and relates to the technical field of soil improvement reagents. The ceramsite for soil improvement is prepared from the following components in percentage by mass: 40-90% of carbonaceous slate, 5-30% of granite slurry and 5-20% of limestone slurry, and the preparation process of the ceramsite for soil improvement comprises the following steps: fully mixing carbonaceous slate powder with the granite slurry and the limestone slurry in proportion; the fully mixed materials are put into a forming machine to be formed and then put into a high-temperature furnace to be subjected to gradient heating calcination, after calcination is completed, the temperature is reduced to the room temperature, and the ceramsite for soil improvement can be obtained. The technical problem that an existing soil conditioner is difficult to consider high porosity, high strength and high water absorption at the same time is solved, and meanwhile the problem that three kinds of solid waste of carbonaceous slate, granite mud and limestone mud are difficult to treat is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil improvement reagents, and particularly relates to a soil conditioner prepared by synergistically using waste and carbonaceous slate and a preparation method thereof. Background Art

[0002] A soil conditioner is a porous material that improves soil by adjusting the following properties of the soil: (1) air permeability. The soil conditioner has a high porosity, which can effectively increase the air permeability of the soil, avoid the soil from being too compact, and thus help the plant roots absorb sufficient oxygen and promote the healthy growth of plants; (2) drainage. The porous structure of the soil conditioner gives it excellent drainage ability. When there is too much water in the soil, the soil conditioner can help the water drain quickly, avoid excessive water accumulation in the plant roots, and reduce the risk of root rot; (3) water retention. The soil conditioner can keep the soil moist for a long time, reducing the frequency and amount of watering; (4) fertilizer retention ability. The soil conditioner can adsorb fertilizers in the pores and release them slowly, avoiding unnecessary loss of fertilizers due to rapid release. It can be seen that to measure the performance of a soil conditioner, it is necessary to consider the porosity, strength, water absorption, etc. of the soil conditioner. However, in actual use, increasing the porosity of the soil conditioner often results in a lower strength of the soil conditioner, making it easy to be damaged during use, resulting in pore blockage and loss of the improvement effect. Therefore, it is very necessary to provide a soil conditioner with high porosity, high strength, and high water absorption. Summary of the Invention

[0003] The present invention provides a soil conditioner prepared by synergistically using waste and carbonaceous slate, so as to solve the technical problems that it is difficult for existing soil conditioners to take into account high porosity, high strength, and high water absorption, and at the same time solve the problem that it is difficult to treat three types of solid wastes, namely carbonaceous slate, granite slurry, and limestone slurry.

[0004] The technical solution adopted by the present invention is as follows:

[0005] One of the purposes of the present invention is to provide a soil conditioner prepared by synergistically using waste and carbonaceous slate. The soil-improving ceramsite is composed of the following components in mass percentage: 40-90% carbonaceous slate, 5-30% granite slurry, and 5-20% limestone slurry. The preparation process of the soil-improving ceramsite is as follows: The carbonaceous slate powder is fully mixed with the granite slurry and the limestone slurry in proportion, and the fully mixed material is put into a molding machine to be molded and then put into a high-temperature furnace for gradient temperature rise calcination. After the calcination is completed, it is cooled to room temperature to obtain the soil-improving ceramsite.

[0006] The three major raw materials used in the present invention are all difficult-to-treat solid wastes. The sources and working principles of the three major raw materials are as follows:

[0007] The carbonaceous slate used is one of the common solid wastes generated during the engineering construction process. In China, the quantity of carbonaceous slate is large, so the volume of carbonaceous slate is huge, which will occupy a large amount of land resources and cause environmental pollution, seriously threatening the survival and development of human beings. It is also extremely difficult to handle. The present invention realizes the resource utilization and harmless treatment of this solid waste, the carbonaceous slate, and solves the current treatment dilemma of carbonaceous slate. The clay component in the carbonaceous slate provides viscous substances for the soil conditioner system, and by utilizing the characteristic that the carbonaceous slate has a certain amount of heat, the heat consumption during the firing process of the soil conditioner is reduced, and the treatment efficiency of this kind of solid waste, the carbonaceous slate, is improved. In addition, the carbonaceous slate is a layered cleavage mineral, and the bonding force between layers is weak. At high temperatures, the particles crack along the layers, which can form a large number of micro-cracks and expand in the soil conditioner system, helping to reduce the bulk density of the soil conditioner and increase the porosity of the soil conditioner.

[0008] The granite slurry used is a solid waste generated during the process of processing granite into granite plates. This solid waste includes a large number of fine particles generated during processing such as sawing and grinding. These fine particles will disperse and suspend in the cooling water. When the cooling water is recycled, these fine particles need to be quickly deposited and removed from the water. Therefore, a certain amount of organic flocculant is added during the deposition process. Thus, this solid waste also contains organic flocculant and needs to be disposed of safely and reasonably. The present invention can directly use this solid waste and solves the treatment problem of granite slurry. The role of granite slurry is to provide silicon dioxide and feldspar: silicon dioxide can increase the silicon content of the soil conditioner to meet the standard for sintering the soil conditioner, improve the strength of the soil conditioner, and at the same time solidify the alkali ions in the raw materials to prevent the rapid dissolution of alkali ions after sintering into the soil conditioner, so as to obtain a high-strength soil conditioner containing useful elements required for soil improvement such as potassium, sodium, and amorphous silicon. During the sintering process, the potassium and sodium ions in the raw materials are solidified, allowing potassium and sodium to be slowly released during the soil improvement process, preventing the rapid dissolution of potassium and sodium ions, and thus avoiding the excessive soil salinity or the loss of potassium and sodium ions; feldspar, as a flux, can reduce the sintering melting point of the soil conditioner and at the same time obtain a soil conditioner material with low density and high strength.

[0009] The limestone mud used is solid waste generated in the process of processing artificial sand and gravel using limestone. This solid waste, like granite mud, also contains fine particles and organic flocculants and needs to be disposed of safely and reasonably. The present invention also directly uses limestone mud, thereby solving the problem of limestone mud treatment. Adding limestone mud as a high-temperature foaming agent has the following functions: the main component of limestone mud is carbonate. During the high-temperature firing process, carbonate decomposes to produce carbon dioxide gas, forming a large number of pores in the soil conditioner system. When the gas escapes from the system, it can also form tiny open pores inside the soil conditioner, which not only further improves the porosity of the soil conditioner, but also increases the water absorption and water retention and fertilizer retention performance of the soil conditioner, providing the soil with water balance and fertility slow release functions.

[0010] Preferably, the carbonaceous slate powder has a mesh size of 100 to 200 meshes.

[0011] The second object of the present invention is to provide a method for preparing the soil conditioner prepared by using the waste in combination with carbonaceous slate, comprising the following steps:

[0012] (1) crushing the carbonaceous slate to obtain carbonaceous slate powder;

[0013] (2) fully mixing the carbonaceous slate powder with the granite mud and the limestone mud to obtain a mixed material;

[0014] (3) preparing soil improvement ceramsite embryos by mixing the mixture in a granulating device;

[0015] (4) placing the soil improvement ceramsite embryo in a high-temperature furnace, raising the furnace temperature to 800-900° C., and keeping the temperature for 60 minutes to achieve the first stage of calcination;

[0016] (5) The furnace temperature continues to rise to 1000-1200°C and is kept at this temperature for 60 minutes to achieve the second stage of calcination;

[0017] (6) After the second stage of calcination is completed, the temperature is quickly cooled to below 500°C and then to room temperature to obtain expanded clay for soil improvement.

[0018] In the present invention, the porosity of the ceramsite for soil improvement is increased through two-stage calcination, which is conducive to the release of ions such as Si, K, and Na in the soil improver. The specific principle is as follows: Keep it at 800 - 900 °C for 60 minutes. This temperature range is the carbonate decomposition temperature range. Keeping it at this stage allows the carbonates in the limestone to decompose fully, so as to provide enough gas phase inside the soil improver system, which is beneficial to improving the porosity of the sintered soil improver; Keep it at 1000 °C - 1200 °C for 60 minutes, and then use air cooling for rapid cooling. This technical feature is conducive to a large temperature difference between the inside and outside of the soil improver particles during the cooling process, increasing the stress in the inner and outer layers of the system, thereby forming more pores in the system and further improving the porosity of the soil improver; Rapid cooling can make the substances in the system exist in an amorphous or low-crystallinity state as much as possible, so that the ions such as Si, K, and Na in the soil improver can be released more easily and slowly later.

[0019] Furthermore, the moisture content of both the granite slurry and the limestone slurry does not exceed 20%.

[0020] To sum up, compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] 1. The ceramsite for soil improvement prepared by the present invention has high porosity, high strength, and high water absorption, and can maintain the soil improvement performance for a long time, solving the problem that soil improvers with high porosity have relatively low strength.

[0022] 2. The present invention solves the problems of the disposal and resource utilization of three common difficult-to-treat solid wastes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the preparation process of the soil improver prepared by the present invention by synergistically using waste and carbonaceous slate;

[0024] Figure 2 It is a physical diagram of the soil improver prepared by synergistically using waste and carbonaceous slate in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] The following will specifically describe the present invention in combination with the specific embodiments and examples, and the advantages and various effects of the present invention will be presented more clearly therefrom. Those skilled in the art should understand that these specific embodiments and examples are used to illustrate the present invention, rather than to limit the present invention.

[0026] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as having the meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as the general understanding of those skilled in the art to which the present invention belongs. In case of conflict, this specification shall prevail.

[0027] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0028] like Figure 1 FIG. 1 is a schematic diagram of the preparation process of the soil conditioner prepared by using waste in combination with carbonaceous slate according to the present invention. The specific preparation process includes the following steps:

[0029] (1) crushing the carbonaceous slate to obtain carbonaceous slate powder, and dehydrating the granite mud and limestone mud raw materials;

[0030] (2) fully mixing the carbonaceous slate powder with the granite mud and the limestone mud to obtain a mixed material;

[0031] (3) preparing soil improvement ceramsite embryos by mixing the mixture in a granulating device;

[0032] (4) placing the soil improvement ceramsite embryo in a high-temperature furnace, raising the furnace temperature to 800-900° C., and keeping the temperature for 60 minutes to achieve the first stage of calcination;

[0033] (5) The furnace temperature continues to rise to 1000-1200°C and is kept at this temperature for 60 minutes to achieve the second stage of calcination;

[0034] (6) After the second stage of calcination is completed, the temperature is quickly cooled to below 500°C and then to room temperature to obtain expanded clay for soil improvement.

[0035] The present application will be described in detail below with reference to embodiments and experimental data.

[0036] Example 1

[0037] The present embodiment provides a method for preparing ceramsite for soil improvement by using carbonaceous slate, granite mud and limestone mud raw materials, comprising the following steps: firstly, crushing the carbonaceous slate into powder of 100-200 meshes, dehydrating the granite mud and limestone mud raw materials to obtain granite mud and limestone mud raw materials with a moisture content of less than 20%, mixing the carbonaceous slate powder with the granite mud and limestone mud, and then preparing a soil improver embryo through a granulating device, and performing gradient heating through a rotary kiln, firstly heating the soil improver embryo from room temperature to 850°C at a heating rate of 20°C / min and keeping the temperature for 60 minutes, then heating from 850°C to 1150°C at a heating rate of 15°C / min and keeping the temperature for 60 minutes, then pouring the soil improver out of the rotary kiln, and quickly cooling the soil improver to below 500°C by air cooling, and then cooling it naturally in the environment. Among the raw materials, the mass fraction of the carbonaceous slate is 70%, the mass fraction of the granite mud is 25%, and the mass fraction of the limestone mud is 5%. The obtained sample is as follows: Figure 2 shown.

[0038] Example 2

[0039] This example provides a method for preparing ceramsite for soil improvement using carbonaceous slate, granite slurry and limestone slurry raw materials, which includes the following steps: First, crush the carbonaceous slate into powders with a particle size of 100-200 mesh, dehydrate the granite slurry and limestone slurry raw materials to obtain granite slurry and limestone slurry raw materials with a water content of less than 20%, mix the carbonaceous slate powders with the granite slurry and limestone slurry, and then make the soil conditioner embryo through a granulation device. Gradually increase the temperature of the soil conditioner embryo through a rotary kiln. First, heat the soil conditioner embryo from room temperature to 850°C at a heating rate of 20°C / minute and keep it warm for 30 minutes, then heat it from 850°C to 1150°C at a heating rate of 15°C / minute and keep it warm for 60 minutes. Then pour out the soil conditioner from the rotary kiln, and quickly cool the soil conditioner to below 500°C by air cooling, and then naturally cool it in the environment. Among them, in the raw materials, the mass fraction of the carbonaceous slate is 70%, the mass fraction of the granite slurry is 25%, and the mass fraction of the limestone slurry is 5%.

[0040] Example 3

[0041] This example provides a method for preparing ceramsite for soil improvement using carbonaceous slate, granite slurry and limestone slurry raw materials, which includes the following steps: First, crush the carbonaceous slate into powders with a particle size of 100-200 mesh, dehydrate the granite slurry and limestone slurry raw materials to obtain granite slurry and limestone slurry raw materials with a water content of less than 20%, mix the carbonaceous slate powders with the granite slurry and limestone slurry, and then make the soil conditioner embryo through a granulation device. Gradually increase the temperature of the soil conditioner embryo through a rotary kiln. First, heat the soil conditioner embryo from room temperature to 850°C at a heating rate of 20°C / minute and keep it warm for 60 minutes, then heat it from 850°C to 1150°C at a heating rate of 15°C / minute and keep it warm for 30 minutes. Then pour out the soil conditioner from the rotary kiln, and quickly cool the soil conditioner to below 500°C by air cooling, and then naturally cool it in the environment. Among them, in the raw materials, the mass fraction of the carbonaceous slate is 70%, the mass fraction of the granite slurry is 25%, and the mass fraction of the limestone slurry is 5%.

[0042] Example 4

[0043] This embodiment provides a method for preparing ceramsite for soil improvement using carbonaceous slate, granite slurry, and limestone slurry raw materials, comprising the following steps: First, crush the carbonaceous slate into powders with a mesh size of 100 - 200, dehydrate the granite slurry and limestone slurry raw materials to obtain granite slurry and limestone slurry raw materials with a moisture content of less than 20%. Mix the carbonaceous slate powders with the granite slurry and limestone slurry, and then use a granulation device to form the embryo of the soil improver. Gradually increase the temperature of the embryo through a rotary kiln. First, heat the embryo of the soil improver from room temperature to 850°C at a heating rate of 20°C per minute and keep it warm for 30 minutes. Then, heat it from 850°C to 1150°C at a heating rate of 15°C per minute and keep it warm for 30 minutes. Then, pour out the soil improver from the rotary kiln, and quickly cool the soil improver to below 500°C by air cooling, and then naturally cool it in the environment. Among them, in the raw materials, the mass fraction of the carbonaceous slate is 70%, the mass fraction of the granite slurry is 25%, and the mass fraction of the limestone slurry is 5%.

[0044] Example 5

[0045] This embodiment provides a method for preparing ceramsite for soil improvement using carbonaceous slate, granite slurry, and limestone slurry raw materials, comprising the following steps: First, crush the carbonaceous slate into powders with a mesh size of 100 - 200, dehydrate the granite slurry and limestone slurry raw materials to obtain granite slurry and limestone slurry raw materials with a moisture content of less than 20%. Mix the carbonaceous slate powders with the granite slurry and limestone slurry, and then use a granulation device to form the embryo of the soil improver. Gradually increase the temperature of the embryo through a rotary kiln. First, heat the embryo of the soil improver from room temperature to 750°C at a heating rate of 20°C per minute and keep it warm for 60 minutes. Then, heat it from 750°C to 1150°C at a heating rate of 15°C per minute and keep it warm for 60 minutes. Then, pour out the soil improver from the rotary kiln, and quickly cool the soil improver to below 500°C by air cooling, and then naturally cool it in the environment. Among them, in the raw materials, the mass fraction of the carbonaceous slate is 70%, the mass fraction of the granite slurry is 25%, and the mass fraction of the limestone slurry is 5%.

[0046] Example 6

[0047] This embodiment provides a method for preparing ceramsite for soil improvement using carbonaceous slate, granite slurry, and limestone slurry raw materials, which includes the following steps: First, crush the carbonaceous slate into powders with a mesh size of 100 - 200, dehydrate the granite slurry and limestone slurry raw materials to obtain granite slurry and limestone slurry raw materials with a moisture content of less than 20%. Mix the carbonaceous slate powders with the granite slurry and limestone slurry, and then use a granulation device to form the embryo of the soil improver. Gradually increase the temperature of the embryo through a rotary kiln. First, heat the embryo of the soil improver from room temperature to 850°C at a heating rate of 20°C per minute and keep it warm for 60 minutes. Then, heat it from 850°C to 950°C at a heating rate of 15°C per minute and keep it warm for 60 minutes. Then, pour out the soil improver from the rotary kiln, and use air cooling to quickly cool the soil improver to below 500°C, and then naturally cool it in the environment. Among them, in the raw materials, the mass fraction of the carbonaceous slate is 70%, the mass fraction of the granite slurry is 25%, and the mass fraction of the limestone slurry is 5%.

[0048] Example 7

[0049] This embodiment provides a method for preparing ceramsite for soil improvement using carbonaceous slate, granite slurry, and limestone slurry raw materials, which includes the following steps: First, crush the carbonaceous slate into powders with a mesh size of 100 - 200, dehydrate the granite slurry and limestone slurry raw materials to obtain granite slurry and limestone slurry raw materials with a moisture content of less than 20%. Mix the carbonaceous slate powders with the granite slurry and limestone slurry, and then use a granulation device to form the embryo of the soil improver. Gradually increase the temperature of the embryo through a rotary kiln. First, heat the embryo of the soil improver from room temperature to 850°C at a heating rate of 20°C per minute and keep it warm for 60 minutes. Then, heat it from 850°C to 1050°C at a heating rate of 15°C per minute and keep it warm for 60 minutes. Then, pour out the soil improver from the rotary kiln, and use air cooling to quickly cool the soil improver to below 500°C, and then naturally cool it in the environment. Among them, in the raw materials, the mass fraction of the carbonaceous slate is 70%, the mass fraction of the granite slurry is 25%, and the mass fraction of the limestone slurry is 5%.

[0050] Example 8

[0051] This embodiment provides a method for preparing ceramsite for soil improvement using carbonaceous slate, granite slurry, and limestone slurry raw materials, which includes the following steps: First, crush the carbonaceous slate into powders with a mesh size of 100 - 200, dehydrate the granite slurry and limestone slurry raw materials to obtain granite slurry and limestone slurry raw materials with a moisture content of less than 20%. Mix the carbonaceous slate powders with the granite slurry and limestone slurry, and then use a granulation device to form the embryo of the soil improver. Heat the embryo through a rotary kiln with a gradient temperature increase. First, heat the embryo of the soil improver from room temperature to 850°C at a heating rate of 20°C per minute and keep it warm for 60 minutes. Then, heat it from 850°C to 1150°C at a heating rate of 15°C per minute and keep it warm for 60 minutes. Then, pour out the soil improver from the rotary kiln, and use air cooling to quickly cool the soil improver to below 500°C, and then naturally cool it in the environment. Among them, in the raw materials, the mass fraction of the carbonaceous slate is 70%, the mass fraction of the granite slurry is 15%, and the mass fraction of the limestone slurry is 15%.

[0052] Example 9

[0053] This embodiment provides a method for preparing ceramsite for soil improvement using carbonaceous slate, granite slurry, and limestone slurry raw materials, which includes the following steps: First, crush the carbonaceous slate into powders with a mesh size of 100 - 200, dehydrate the granite slurry and limestone slurry raw materials to obtain granite slurry and limestone slurry raw materials with a moisture content of less than 20%. Mix the carbonaceous slate powders with the granite slurry and limestone slurry, and then use a granulation device to form the embryo of the soil improver. Heat the embryo through a rotary kiln with a gradient temperature increase. First, heat the embryo of the soil improver from room temperature to 850°C at a heating rate of 20°C per minute and keep it warm for 60 minutes. Then, heat it from 850°C to 1150°C at a heating rate of 15°C per minute and keep it warm for 60 minutes. Then, pour out the soil improver from the rotary kiln, and use air cooling to quickly cool the soil improver to below 500°C, and then naturally cool it in the environment. Among them, in the raw materials, the mass fraction of the carbonaceous slate is 60%, the mass fraction of the granite slurry is 35%, and the mass fraction of the limestone slurry is 5%.

[0054] Example 10

[0055] This embodiment provides a method for preparing ceramsite for soil improvement using carbonaceous slate, granite slurry, and limestone slurry as raw materials, which includes the following steps: First, crush the carbonaceous slate into powders with a particle size of 100 - 200 meshes. Dehydrate the granite slurry and limestone slurry raw materials to obtain granite slurry and limestone slurry raw materials with a moisture content of less than 20%. Mix the carbonaceous slate powder with the granite slurry and limestone slurry, and then use granulation equipment to make the soil conditioner embryo. Gradually increase the temperature of the embryo in a rotary kiln. First, heat the soil conditioner embryo from room temperature to 850°C at a heating rate of 20°C per minute and hold for 60 minutes. Then, heat it from 850°C to 1150°C at a heating rate of 15°C per minute and hold for 60 minutes. Then, pour out the soil conditioner from the rotary kiln, and quickly cool the soil conditioner to below 500°C by air cooling, and then naturally cool it in the environment. Among the raw materials, the mass fraction of the carbonaceous slate is 50%, the mass fraction of the granite slurry is 35%, and the mass fraction of the limestone slurry is 15%.

[0056] Perform strength, water absorption, and density tests on the ceramsite for soil improvement prepared in the above 10 embodiments. The test results are shown in Table 1.

[0057] Table 1 Test results of strength, water absorption, and density of each sample

[0058]

[0059]

[0060] According to the data in Table 1, from the perspective of the preparation process, both the temperature and time of two-stage calcination will affect the performance of the product. When the calcination temperature and time are insufficient, the ceramsite for soil improvement obtained is undercalcined (Examples 6 and 7), resulting in low strength. From the formula perspective, the density of the soil solidifier is more related to the dosage of raw materials in the formula, the water absorption is more related to the dosage of limestone slurry, and the strength of the soil solidifier is more related to the dosage of granite slurry. The required performance of the soil solidifier can be adjusted according to this result. The soil conditioners prepared by the method of the present invention all have good water absorption, indicating that the soil conditioner system prepared by this method has abundant open pores, which can meet the requirements of water retention, fertilizer retention, and ventilation of the soil conditioner. The soil conditioners prepared by the method of the present invention all have high strength and can exist in the soil for a long time without being easily damaged.

[0061] Finally, it should also be noted that the terms "comprise", "include" or any other variants are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0062] The above-described embodiments merely represent the specific implementation manners of the present application, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the protection scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the technical solution of the present application, several variations and improvements can still be made, and these all fall within the protection scope of the present application.

Claims

1. A soil conditioner prepared from waste and carbonaceous slate, characterized in that: The soil-improving ceramsite is composed of the following components in mass percentage: 40-90% carbonaceous slate, 5-30% granite mud, and 5-20% limestone mud. The preparation process of the soil-improving ceramsite is: carbonaceous slate powder is fully mixed with granite mud and limestone mud in proportion, the fully mixed materials are put into a molding machine for molding, and then put into a high-temperature furnace for gradient temperature calcination, and after the calcination is completed, the temperature is lowered to room temperature to obtain the soil-improving ceramsite.

2. The soil conditioner prepared by waste and carbonaceous slate according to claim 1, characterized in that: The mesh size of the carbonaceous slate powder is 100-200 meshes.

3. The method for preparing a soil conditioner prepared by using waste and carbonaceous slate as claimed in claim 1 or 2, characterized in that: The steps include: (1) crushing the carbonaceous slate to obtain carbonaceous slate powder; (2) fully mixing the carbonaceous slate powder with the granite mud and the limestone mud to obtain a mixed material; (3) preparing soil improvement ceramsite embryos by mixing the mixture in a granulating device; (4) placing the soil improvement ceramsite embryo in a high-temperature furnace, raising the furnace temperature to 800-900° C., and keeping the temperature for 60 minutes to achieve the first stage of calcination; (5) The furnace temperature continues to rise to 1000-1200°C and is kept at this temperature for 60 minutes to achieve the second stage of calcination; (6) After the second stage of calcination is completed, the temperature is quickly cooled to below 500°C and then to room temperature to obtain expanded clay for soil improvement.

4. The method for preparing a soil conditioner prepared by using waste and carbonaceous slate as claimed in claim 3, characterized in that: The water content of the granite mud and the limestone mud does not exceed 20%.

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