Carbon sequestration and soil amendment type soil amendment based on iron tailings sand and preparation method

Abstract

The application belongs to the technical field of soil improvement, and provides a carbon sequestration and soil improvement agent based on iron tailings sand and a preparation method thereof, which comprises the following steps: S1, grinding the iron tailings sand by using a ball mill and sieving to obtain iron tailings powder, and drying to constant weight; drying the biomass material naturally, crushing by using a crusher, sieving, obtaining biomass material powder, and drying to constant weight again; S2, uniformly mixing the biomass material and the iron tailings sand according to different proportions; S3, preparing the iron tailings sand-biochar composite material by using a one-step pyrolysis method under a set temperature condition, and preparing the soil improvement agent. The application provides an effective recycling way for reasonably treating large iron tailings sand, reduces the occupation of land resources by the tailings sand and possible environmental pollution and safety hazards; on the other hand, the application realizes the utilization of waste biomass material, and makes a positive contribution to solving the problem of soil degradation, realizing sustainable utilization of resources and promoting sustainable development of agriculture.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, specifically to a carbon sequestration and fertilization soil conditioner based on iron tailings sand and its preparation method. Background Technology

[0002] Iron tailings refers to the waste generated during the iron ore beneficiation process, that is, the ore residue remaining after iron is extracted from iron ore. Iron tailings usually contain a certain amount of minerals such as iron, silicon, and aluminum. Although its main component is useless waste, the large amount of iron tailings formed during industrial development poses a serious threat to the surrounding residents and ecological safety. How to properly handle and realize the resource utilization of iron tailings is an important issue that urgently needs to be solved.

[0003] The recycling and utilization of iron ore tailings is an important topic in environmental protection and resource reuse. Iron tailings are generated as a byproduct during iron ore beneficiation and are generally considered waste, but they actually have certain economic value and application potential. Currently, the main directions and methods for iron tailings recycling and utilization are mostly concentrated in the building materials industry and road engineering, with relatively little research on its application in soil improvement. Soil improvement is of great significance for improving soil quality, promoting crop growth, and ensuring food security.

[0004] The present invention aims to provide a carbon sequestration and fertilization soil conditioner based on iron tailings sand and its preparation method, so as to realize the resource utilization of iron tailings sand and improve soil properties. Summary of the Invention

[0005] The purpose of this invention is to provide a carbon sequestration and fertilization soil conditioner based on iron tailings sand and its preparation method, so as to solve the problem of resource utilization of iron tailings in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of the present invention provides a method for preparing a carbon sequestration and fertilization-enhancing soil conditioner based on iron tailings sand, comprising the following steps: S1. Iron tailings sand is ground and sieved using a ball mill to obtain iron tailings powder, which is then dried to constant weight. Biomass material is air-dried, pulverized and sieved to obtain biomass material powder, which is then dried to constant weight. S2, mix biomass materials and iron tailings sand evenly in different proportions; S3, using a one-step pyrolysis method under set temperature conditions, slowly pyrolyzes iron tailings sand-biochar composite material to obtain a soil conditioner.

[0007] Preferably, the tailings sand has a pH of 7.8, and the mass percentages of each chemical component in the tailings sand are as follows: Iron oxide 6.01%, potassium oxide 7.43%, calcium oxide 6.06%, magnesium oxide 7.35%, the remainder being impurities.

[0008] Preferably, the iron tailings in S1 are ground, passed through a 100-mesh sieve, and dried at 80°C to a constant weight.

[0009] Preferably, in step S1, the biomass material is pulverized, passed through a 100-mesh sieve, and dried at 80°C to a constant weight.

[0010] Preferably, the biomass material includes, but is not limited to, corn stalks or rice stalks.

[0011] Preferably, the mixing mass ratio of biomass material and iron tailings sand in S2 is 7:3, 5:5 or 3:7.

[0012] Preferably, the temperature of the one-step pyrolysis method in S3 is 400℃ or 800℃.

[0013] A second aspect of the present invention provides a soil conditioner, which is prepared by the method described in the first aspect of the present invention.

[0014] A third aspect of the present invention provides a method for evaluating the soil conditioner described in the second aspect of the present invention, comprising the following steps: S1, take soil with excessive heavy metals, add soil conditioner in proportion, and mix thoroughly; Add an appropriate amount of deionized water to S2 to bring the soil moisture to 60% of field capacity. After equilibration for a period of time, measure the changes in the physical, chemical and biological properties of the soil before and after application.

[0015] The fourth aspect of the present invention provides an application of the soil conditioner described in the second aspect of the present invention, wherein the soil conditioner is used for soil improvement, solving soil degradation problems, achieving sustainable resource utilization, and promoting sustainable agricultural development.

[0016] This invention has at least the following beneficial effects: This invention provides a carbon sequestration and fertilization soil conditioner based on iron tailings sand and its preparation method. On the one hand, it provides an effective way to reuse large iron tailings sand, reducing the land occupation caused by tailings sand and the potential environmental pollution and safety hazards. On the other hand, it enables the utilization of waste biomass materials, which can make a positive contribution to solving soil degradation problems, achieving sustainable resource utilization, and promoting sustainable agricultural development. Attached Figure Description

[0017] Figure 1 This invention provides the carbon yield and standard for iron tailings sand-biochar composite materials with different materials and temperatures. Figure 2Scanning electron microscope (SEM) images of fermentation residue raw materials at 10 μm, and samples at 400℃ and 800℃. Figure 3 SEM image of 1μm rice straw fermentation residue biochar material; Figure 4 SEM images (10 μm) of tailings sand under different pyrolysis temperatures. Figure 5 The morphology of tailings sand-rice straw mixture before and after pyrolysis in a 7:3 ratio and the morphology of tailings sand-corn straw mixture before and after pyrolysis in a 7:3 ratio. Figure 6 The morphology of tailings sand-rice straw 5:5 mixture before and after pyrolysis and the morphology of tailings sand-corn straw 5:5 mixture before and after pyrolysis; Figure 7 The morphology of tailings sand-rice straw 3:7 mixture before and after pyrolysis and the morphology of tailings sand-corn straw 3:7 mixture before and after pyrolysis; Figure 8 SEM images of tailings sand + rice straw in a 7:3 ratio and tailings sand + rice straw in a 3:7 ratio; Figure 9 SEM images of tailings sand + corn stalks in a 7:3 ratio and tailings sand + corn stalks in a 3:7 ratio; Figure 10 Comparison of XRD patterns of corn stalks; Figure 11 Comparison of XRD patterns of rice straw; Figure 12 Comparison of XRD patterns of tailings sand; Figure 13 Comparison of XRD patterns of a 7:3 mixture of tailings sand and rice straw; Figure 14 Comparison of XRD patterns of a 7:3 mixture of tailings sand and corn stalks; Figure 15 Comparison of XRD patterns of tailings sand and rice straw in a 5:5 ratio; Figure 16 Comparison of XRD patterns of tailings sand and corn stalks at a 5:5 ratio; Figure 17 XRD pattern of a 3:7 mixture of tailings sand and rice straw; Figure 18 XRD pattern of a 3:7 mixture of tailings sand and corn stalks; Figure 19 This is a diagram of the experimental setup for the present invention. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This invention uses iron tailings sand as the main raw material and combines it with two different types of biomass raw materials, namely corn stalks and rice stalks, through a one-step pyrolysis method to prepare iron tailings sand-biochar composite material. This composite material is then used to improve the soil around the mining area. The invention elucidates the improvement effect and mechanism of this material on the soil around the mining area from the perspectives of physical, chemical, and biological properties. This provides a new approach for the comprehensive utilization of iron tailings sand and offers theoretical basis and technical support for improving the regional soil environment.

[0020] To address the comprehensive utilization of iron tailings in the Chengde area, this study used iron tailings as the main raw material and combined it with two different biomass raw materials, corn and rice, to prepare an iron tailings-biochar composite material. The study elucidated its soil-improvement effects and mechanisms around the mining area. Specific research contents are as follows: (1) Characterization of iron tailings sand and biomass raw materials The microstructure, mineral phases, elemental composition, and functional groups of biomass such as rice and corn, as well as iron tailings sand, were analyzed using various characterization methods including specific surface area (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR), providing a theoretical basis for the preparation of iron tailings sand-biochar composite materials.

[0021] (2) Preparation and characterization of iron tailings sand-biochar composite material Rice, corn stalks and tailings sand were mixed in different proportions and then slowly pyrolyzed at different temperatures (400℃ and 800℃) using a one-step pyrolysis method to prepare iron tailings sand-biochar composite materials. The physicochemical properties of the prepared materials were measured and characterized, and the influence mechanism of raw material ratio and pyrolysis temperature was explored to provide data support for the application of composite materials.

[0022] (3) Study on the soil improvement effect of iron tailings sand-biochar composite material Based on the results of previous field investigations, we selected farmland in the mountainous area of ​​northern Hebei Province with heavy metal contamination (cadmium and lead). Through indoor soil incubation experiments, we investigated the changes in the physical, chemical, and biological properties of soil before and after the application of different iron tailings sand-biochar composite materials with different addition amounts (0%, 0.5%, 1%, and 3%). We constructed a comprehensive index to reflect its soil improvement effect, thereby evaluating the soil improvement effect of different materials and addition amounts, and analyzing its internal mechanism in combination with material characteristics.

[0023] Based on the above technical approach, the present invention provides the following partial embodiments: Example 1 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand, including the following steps: S1. Iron tailings sand is ground using a ball mill and passed through a 100-mesh sieve to obtain iron tailings powder, which is then dried at 80°C to constant weight. Rice straw is naturally air-dried, then crushed using a pulverizer and passed through a 100-mesh sieve to obtain biomass material powder, which is then dried at 80°C to constant weight. The tailings sand used in this embodiment came from Hebei Fuyuan Mining Co., Ltd. The tailings sand had a pH of 7.8, an arsenic content of 1.87 mg / kg, cadmium not detected, a chromium content of 925 mg / kg, a copper content of 307 mg / kg, a lead content of 138 mg / kg, a nickel content of 127 mg / kg, a nitrogen content of 1780 mg / kg, a phosphorus content of 3413 mg / kg, a sulfur content of 11250 mg / kg, a selenium content of 0.09 mg / kg, an iron content of 101875 mg / kg, and a mercury content of 0.025 mg / kg. Its chemical composition included 6.01% iron oxide, 7.43% potassium oxide, 6.06% calcium oxide, and 7.35% magnesium oxide. S2, mix rice straw and iron tailings sand evenly at a mass ratio of 10:0 (pure rice straw). S3, using a one-step pyrolysis method at 400℃, slowly pyrolyzes iron tailings sand-biochar composite material to prepare a soil conditioner.

[0024] Example 2 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is corn stalks; the corn stalks and iron tailings sand are mixed evenly at a mass ratio of 10:0 (pure corn stalks); the one-step pyrolysis method is performed at a temperature of 400℃.

[0025] Example 3 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material and iron tailings sand are mixed evenly at a mass ratio of 0:10 (pure iron tailings sand); the one-step pyrolysis method is performed at a temperature of 400℃.

[0026] Example 4 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is rice straw; the rice straw and iron tailings sand are mixed evenly at a mass ratio of 10:0 (pure rice straw); the one-step pyrolysis method is performed at a temperature of 800℃.

[0027] Example 5 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is corn stalks; the corn stalks and iron tailings sand are mixed evenly at a mass ratio of 10:0 (pure corn stalks); the one-step pyrolysis method is performed at a temperature of 800℃.

[0028] Example 6 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material and iron tailings sand are mixed evenly at a mass ratio of 0:10 (pure iron tailings sand); the one-step pyrolysis method is performed at a temperature of 800℃.

[0029] Example 7 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is rice straw; the rice straw and iron tailings sand are mixed evenly at a mass ratio of 3:7; and the one-step pyrolysis method is performed at a temperature of 400℃.

[0030] Example 8 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is corn stalks; the corn stalks and iron tailings sand are mixed evenly at a mass ratio of 3:7; and the one-step pyrolysis method is performed at a temperature of 400℃.

[0031] Example 9 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand, the difference being that the biomass raw material is rice straw; the rice straw and iron tailings sand are mixed evenly at a mass ratio of 5:5; and the one-step pyrolysis method is performed at a temperature of 400℃.

[0032] Example 10 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is corn stalks; the corn stalks and iron tailings sand are mixed evenly at a mass ratio of 5:5; and the one-step pyrolysis method is performed at a temperature of 400℃.

[0033] Example 11 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is rice straw; the rice straw and iron tailings sand are mixed evenly at a mass ratio of 7:3; and the one-step pyrolysis method is performed at a temperature of 400℃.

[0034] Example 12 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is corn stalks; the corn stalks and iron tailings sand are mixed evenly at a mass ratio of 7:3; and the one-step pyrolysis method is performed at a temperature of 400℃.

[0035] Example 13 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is rice straw; the rice straw and iron tailings sand are mixed evenly at a mass ratio of 3:7; and the one-step pyrolysis method is performed at a temperature of 800℃.

[0036] Example 14 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is corn stalks; the corn stalks and iron tailings sand are mixed evenly at a mass ratio of 3:7; and the one-step pyrolysis method is performed at a temperature of 800℃.

[0037] Example 15 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand, the difference being that the biomass raw material is rice straw; the rice straw and iron tailings sand are mixed evenly at a mass ratio of 5:5; and the one-step pyrolysis method is performed at a temperature of 800℃.

[0038] Example 16 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is corn stalks; the corn stalks and iron tailings sand are mixed evenly at a mass ratio of 5:5; and the one-step pyrolysis method is performed at a temperature of 800℃.

[0039] Example 17 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand. The difference is that the biomass raw material is rice straw; the rice straw and iron tailings sand are mixed evenly at a mass ratio of 7:3; and the one-step pyrolysis method is performed at a temperature of 800℃.

[0040] Example 18 This example provides a method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand, the difference being that the biomass raw material is corn stalks; the corn stalks and iron tailings sand are mixed evenly at a mass ratio of 7:3; and the one-step pyrolysis method is performed at a temperature of 800℃.

[0041] The soil conditioners provided in Examples 1-18 above were evaluated as follows: (1) Soil culture experiment Heavy metal contamination soil (cadmium and lead) was selected from farmland surrounding a metal smelter in the northern Hebei mountainous area. Through indoor soil incubation experiments, different iron tailings sand-biochar composite materials (0%, 0.5%, 1%, 3%, and 5%) were added in proportion and thoroughly mixed. An appropriate amount of deionized water was added to bring the soil moisture to 60% of field capacity. After a period of equilibration, the changes in the physical, chemical, and biological properties of the soil before and after application were measured.

[0042] (2) Characterization of basic properties of raw materials and composite materials The thermal stability and compositional properties of the materials were determined using a thermogravimetric analyzer; the C, H, and N elemental contents were determined using a CHN elemental analyzer, and the O elemental content was obtained by subtraction. According to the national standard GB-T212-2008, industrial analysis of the biomass raw materials was conducted using a muffle furnace. The heavy metal content in the raw materials was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). X-ray diffraction was performed using an X-ray powder diffractometer (Brook D8 ADVANCE); Fourier transform infrared spectroscopy was performed using a Fourier transform infrared spectroscopy analyzer; and the BET specific surface area was determined using a physical adsorption analyzer (ASAP 2460, Mack, USA). Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analysis was performed using a combination of scanning electron microscopy (Hitachi SU8020) and EDS (HORIBA EX-350); transmission electron microscopy (TEM) was performed using a field emission transmission electron microscope (FEI Tecnai G2 F20).

[0043] (3) Determination of soil physicochemical properties ① Physical properties Soil particle composition was determined using methods such as laser particle size analyzer; total porosity, capillary porosity, and non-capillary porosity were calculated using soil bulk density and specific gravity data. Soil field capacity, saturated water content, and wilting coefficient were also measured.

[0044] ② Chemical properties pH was determined using the electrode potential method; cation exchange capacity was determined using the barium chloride-sulfuric acid forced exchange method; organic matter content was determined using the sulfuric acid digestion-potassium dichromate external heating method; hydrolyzable nitrogen content was determined using the alkaline diffusion method; available phosphorus content was determined using the NaHCO3 extraction-molybdenum antimony colorimetric method; and available potassium content was determined using the NH4OAc extraction-flame photometry method. The total lead and cadmium content in the soil was determined using an aqua regia-perchloric acid system; and the BCR stepwise extraction method was used to extract different forms of lead and cadmium.

[0045] ③ Biological properties The community structure and diversity of microorganisms in soil were analyzed using high-throughput sequencing technology and other methods.

[0046] (4) Results Analysis: ① Carbon production rate (e.g.) Figure 1 (As shown) At 400°C, pure tailings sand (I, Example 3) exhibited the highest char yield, reaching 99.86%, while corn stalks (M, Example 2) showed the lowest, at only 36.41%. As the temperature increased to 800°C, the char yield of pure tailings sand (W, Example 6) decreased slightly to 98.51%, while the char yield of pure corn stalks (Y, Example 5) decreased significantly to 26.47%. This indicates that high temperature has a significant impact on the carbonization process of corn stalks. The char yield of the composite material fell between that of the pure materials, and decreased with increasing biomass feedstock ratio. For example, the char yield of W:S 7:3 was 83.00% at 400°C, but only 78.68% at 800°C. This may be because biomass feedstocks decompose more easily at high temperatures, leading to a lower char yield.

[0047] By analyzing the average carbon yield of different ratio combinations, the average carbon yield of different ratio combinations at 400℃ and 800℃ was further shown. It can be seen that the combination with a higher proportion of tailings sand (such as W and W:S 7:3) has a higher carbon yield at both temperatures, while the combination with a higher proportion of corn stalks (such as W:Y 3:7) has a lower carbon yield.

[0048] This study experimentally analyzed the carbon yield and standard deviation of iron tailings sand-biochar composite materials under different materials and temperatures. The results showed that the composite material with a higher proportion of tailings sand had a higher carbon yield at both temperatures, while the composite material with a higher proportion of corn stalks had a lower carbon yield.

[0049] ② Elemental analysis Table 1 shows the elemental analysis data of biomass and tailings sand before and after pyrolysis at different temperatures. Figure 1 It can be seen that, both before and after pyrolysis, the C content of corn straw is significantly higher than that of rice straw, while the N and S contents are both lower, indicating that the pollutants generated from biomass carbon fertilizer production are minimal and the C source is abundant. The C / N ratio of corn straw is also much higher than that of rice straw. Before pyrolysis and at a low temperature of 400℃, the H content and C / H ratio of corn straw are slightly higher than those of rice straw. However, at a high temperature of 800℃, the C / H ratio of rice straw is slightly higher than that of corn straw. This may be because the high temperature causes water evaporation, resulting in a lower H content in the corn straw biomass. Regardless of whether it is before or after pyrolysis, the content of each element in the tailings sand is very low, indicating that the nutrient content in the tailings sand is very low.

[0050] Table 1. Elemental analysis of biomass and tailings sand before and after pyrolysis

[0051] Table 2 shows the elemental analysis data of rice straw and tailings sand composite materials and pyrolysis at different proportions and temperatures. Figure 2It can be seen that the C content increases with the increase of the proportion of rice straw, both before pyrolysis and after pyrolysis at different temperatures. The C / N ratio is highest when tailings sand and rice straw are mixed in a 5:5 ratio before pyrolysis, highest when tailings sand and rice straw are mixed in a 3:7 ratio at 400℃, and highest when tailings sand and rice straw are mixed in a 7:3 ratio at 800℃. The C / H ratio generally decreases gradually with the decrease of the proportion of rice straw before pyrolysis and at low temperature (400℃), but increases with the increase of biomass content at high temperature (800℃). The contents of N, S, and H are all relatively low and not significantly related to changes in pyrolysis temperature or the proportion of tailings sand and rice straw. Only the H content increases steadily and significantly with the increase of the proportion of biomass before pyrolysis, possibly due to the moisture content of the rice straw itself.

[0052] Table 2 Elemental analysis of tailings sand-rice composite material before and after pyrolysis

[0053] Table 3 shows the elemental analysis data of rice straw and tailings sand composite materials and pyrolysis at different proportions and temperatures. Figure 2-6 It can be seen that the C content increases with the increase of the proportion of corn stalks, both before and after pyrolysis at different temperatures. The C / N ratio gradually increases with the increase of the proportion of corn stalks, both before and after pyrolysis at different temperatures, reaching its highest value at a tailings sand to corn stalk ratio of 3:7. Before pyrolysis and at a low temperature of 400℃, the C / N content of the tailings sand to corn stalk ratio of 3:7 is not much different from that of corn stalks. However, at a high temperature of 800℃, the C / N ratio of corn stalks is significantly lower than that of tailings sand to corn stalks at a 3:7 ratio. The C / H value remains generally stable before pyrolysis and at a high temperature of 800℃, and does not change with the ratio. However, at 400℃, the C / H value first increases and then decreases with the increase of biomass content, reaching its highest value at a ratio of 5:5. The contents of N, S, and H elements were all low and not significantly related to changes in pyrolysis temperature and the ratio of tailings sand to rice straw. Only the H element content was higher in corn straw biomass before pyrolysis and during low-temperature pyrolysis at 400℃, which may be due to the moisture content of the corn straw itself.

[0054] Table 3 Elemental analysis of tailings sand and corn straw composite materials before and after pyrolysis

[0055] The microstructure of biochar samples was evaluated using SEM microscopy. SEM images of fermentation residue biochar prepared at different pyrolysis temperatures are shown below. Figure 2 As shown.

[0056] Figure 2The images show scanning electron microscope (SEM) images of fermentation residue raw materials at 10 μm, samples at 400℃, and samples at 800℃. Analysis of the surface structure of rice straw and corn straw biochar reveals that: (a) the surface of rice straw biochar raw materials is relatively smooth and intact, with a uniform microstructure, maintaining the original plant fiber structure characteristics; (b) after pyrolysis at 400℃, the surface is covered with a large number of irregular lumps, becoming rougher, possibly due to the decomposition, recombination, or migration and aggregation of some substances during pyrolysis; (c) after pyrolysis at 800℃, the surface lumps are significantly reduced and tend to be smoother, possibly due to the high temperature causing the ablation and melting of small surface fragments or further decomposition and volatilization of some substances. The surface of corn straw biochar raw material (d) is smooth and intact, similar to that of rice straw biochar raw material; after pyrolysis at 400℃, (e) the surface is covered with a large number of irregular lumps, affecting surface smoothness and microstructure uniformity; after pyrolysis at 800℃, (f) the surface lumps are significantly reduced and become smooth, which is due to the ablation, melting, or further decomposition and volatilization of small surface fragments under high temperature, eliminating the lumps. Under the influence of pyrolysis temperature, the surface structure changes of the two types of straw biochar have similar trends, but due to the different raw materials, the shape, size, and distribution of surface lumps differ at the same pyrolysis temperature.

[0057] Overall, the effects of pyrolysis temperature on the surface structure of rice straw and corn straw biochar are largely similar. As the pyrolysis temperature increases from 400℃ to 800℃, the irregular lumps on the surface of both types of biochar decrease significantly, and the surfaces tend to become smoother. This indicates that at higher pyrolysis temperatures, the surface structure of biochar undergoes similar physical and chemical changes such as ablation, melting, and decomposition of surface substances. However, rice straw and corn straw have different original characteristics such as chemical composition and fiber structure, and their decomposition and recombination methods differ during pyrolysis. Therefore, at the same pyrolysis temperature (e.g., 400℃), the lumps attached to the surface of the two biochars may differ in shape, size, and distribution.

[0058] Simultaneously, SEM images of rice straw fermentation residue biochar materials were studied at 1 μm magnifications of 3500 and 9000, such as... Figure 3 As shown, the pyrolysis products of rice straw exhibit the following significant characteristics: the presence of widely distributed pores and cracks provides the material with excellent adsorption capacity and specific surface area. The microcracks and irregular surface offer the composite material more opportunities to bind with heavy metal ions. This microstructure of biochar is highly suitable for combining with tailings sand to form composite materials, significantly improving its remediation effect on contaminated soil.

[0059] The surface structure of tailings sand was analyzed at a magnification of 10 μm to investigate the effect of pyrolysis temperature on the microstructure of the tailings sand. Figure 4As shown, at a magnification of 10 μm, the surface of the tailings raw material is smooth, with uniform particle distribution and stable structure. After pyrolysis at 400℃, fine particles adhere to the surface and are unevenly distributed, increasing roughness and generating microcracks, thus reducing structural stability. After pyrolysis at 800℃, the number of fine particles on the surface increases, large-sized lumps appear, roughness increases dramatically, the number and width of cracks increase and interconnect, the structure becomes loose, and stability decreases significantly. This study indicates that increasing the pyrolysis temperature deteriorates the microstructure of tailings, providing a basis for subsequent resource utilization and material performance optimization of tailings.

[0060] Comprehensive analysis shows that the surface structure of tailings sand changes with increasing pyrolysis temperature. Higher pyrolysis temperatures promote the increase of surface particles, the formation and growth of lumps, the continuous development of cracks, and the appearance of cavities. These changes in microstructure indicate that pyrolysis temperature affects the physical properties and structural stability of tailings sand; the higher the pyrolysis temperature, the stronger the destructive and remodeling effect on the microstructure of tailings sand. This provides an important theoretical basis for studying the performance changes of tailings sand under different pyrolysis conditions.

[0061] Analysis based on different mixing ratios: The morphology of the tailings sand-rice straw mixture before and after pyrolysis in a 7:3 ratio is as follows: Figure 5 As shown in (a), (b), and (c), the surface of rice straw before pyrolysis has fewer pores, while the biochar of rice straw after pyrolysis has well-developed pores and a honeycomb structure; the morphology of tailings sand-corn straw 7:3 mixture before and after pyrolysis is as follows. Figure 5 As shown in (d), (e), and (f), the surfaces of corn stalks before and after pyrolysis are relatively smooth and have few pores. This is likely because the temperature and atmosphere during pyrolysis were well controlled, resulting in minimal surface changes. The mineral composition of the tailings sand is relatively stable, while the organic matter in the corn stalks, although carbonized, still maintains a relatively smooth surface.

[0062] The morphology of a 5:5 mixture of tailings sand and rice straw before and after pyrolysis is as follows: Figure 6 As shown in (a), (b), and (c), the rice straw portion of the mixed material before pyrolysis has fewer surface pores, and the main body exhibits various forms such as elongated strips and flakes, mixed with tailings sand particles, resulting in a relatively loose overall structure. After pyrolysis at 400℃, the original morphology of the rice straw biochar is still visible on the surface, but it becomes relatively loose, with increased pores; the main structure remains a mixture of elongated strips and flakes. After pyrolysis at 800℃, the surface of the rice straw biochar is rougher, with a significantly increased and more developed pore structure, resulting in a looser overall structure. The morphology of the 5:5 tailings sand-corn straw mixture before and after pyrolysis is shown in the figure. Figure 6As shown in (d), (e), and (f), the surface of the corn stalks before pyrolysis has limited smoothness, and the main body consists of irregular blocks and strip-like structures, forming a relatively chaotic mixture with the tailings sand. After pyrolysis at 400℃, the corn stalk biochar exhibits a certain degree of porous structure, with the strip-like structure becoming more pronounced, and the overall structure becoming looser. After pyrolysis at 800℃, the surface roughness increases, the porosity increases, the main body remains strip-like, and the structure becomes even more porous. During pyrolysis, the mineral composition of the tailings sand is relatively stable, having little impact on the overall morphology of the mixed material. The main changes are in the structure and morphology of the rice straw and corn stalks during pyrolysis. The organic matter in the straw decomposes, some volatilizes, and some recombines and polymerizes at high temperatures, leading to increased porosity and specific surface area in the biochar. This facilitates the diffusion and adsorption of pollutants in the material, providing better conditions for related applications.

[0063] Overall, with increasing pyrolysis temperature, the pore structure of rice straw and corn straw gradually increases and becomes more developed, with the morphology changing from relatively dense to loose. Under different mixing ratios, the higher the proportion of straw, the more obvious the change in pore structure after pyrolysis. In particular, the changes in pore structure and overall morphology are most significant after pyrolysis of tailings sand-rice straw 3:7 mixture and tailings sand-corn straw 3:7 mixture at 800℃, which is conducive to the diffusion and adsorption of pollutants.

[0064] The morphology of the tailings sand-rice straw mixture before and after pyrolysis (3:7 ratio) is as follows: Figure 7 As shown in (a), (b), and (c), the rice straw portion of the mixed material before pyrolysis has a relatively dense surface and sparse pores. Its appearance is characterized by a variety of elongated and sheet-like interwoven shapes, which are disorderly mixed with tailings sand particles, and the overall structure lacks regularity. When pyrolyzed to 400℃, the original morphological outline of the rice straw biochar is still preserved, but the surface has become significantly loose, and the number of pores has increased. Some micropores with a diameter of about 10-15μm have appeared, and the elongated and sheet-like structures have a tendency to merge. After further pyrolysis to 800℃, the pores of the rice straw biochar show an explosive growth and a remarkable degree of development. A large number of channels with a diameter of about 20-30μm are crisscrossed, like a precise honeycomb structure. The overall structure becomes extremely loose, and the sheet-like structure is almost broken and integrated into the pore system. Before pyrolysis of tailings sand and corn stalks in a 3:7 ratio, the corn stalks are mainly rod-shaped with a relatively smooth and flat surface, only occasionally with slight bumps and dents. The pores are almost invisible, and the mixture with the tailings sand particles is simple and slightly messy. When the pyrolysis temperature reaches 400℃, the rod-shaped characteristics of the corn stalk biochar become more prominent, and the surface begins to show porous features. The smaller pores are distributed in a dotted pattern, which makes the originally compact rod-shaped structure gradually loosen. When the pyrolysis temperature reaches 800℃, the corn stalk biochar shows obvious stratification.

[0065] like Figure 8In the 7:3 mixture of tailings sand and rice straw raw materials (a), the tailings sand particles are relatively large, irregularly shaped, and have a relatively smooth surface, while the rice straw biochar particles are smaller and dispersed among the tailings sand particles, resulting in a relatively loose overall structure. After pyrolysis at 400℃ (b), the particle surface becomes rough, with some small attached particles appearing, possibly due to new substances or structural changes generated during pyrolysis. The boundaries between particles remain relatively clear, but agglomeration begins in some areas. After pyrolysis at 800℃ (c), the particle surface changes further, with a significant increase in roughness and the formation of larger lumps, due to particle agglomeration and sintering at high temperatures. The boundaries between particles become blurred, and the overall structure becomes denser, possibly because the high temperature causes stronger bonding or reaction between the materials.

[0066] In the 3:7 mixture of tailings sand and rice straw (d), the rice straw biochar content is relatively high, resulting in a denser distribution of small particles. The tailings sand particles are surrounded by a large number of biochar particles, exhibiting a relatively loose and complex overall structure. After pyrolysis at 400℃ (e), many fine particles adhere to the surface, and adhesion begins between particles. The structure in some areas becomes more compact, possibly due to some interaction between the biochar and tailings sand caused by pyrolysis. After pyrolysis at 800℃ (f), the structural changes are more pronounced, with a large number of agglomerates appearing. The block size is larger and the surface is rougher, and the density of the structure is further improved, indicating that high-temperature pyrolysis has a significant reshaping effect on the microstructure of this mixture.

[0067] As the pyrolysis temperature increases, the microstructure of biochar + tailings sand materials with different ratios undergoes significant changes, with increased surface roughness and more pronounced particle agglomeration and sintering. The ratio of rice straw to biochar also affects the microstructure of the material; when the biochar ratio is higher (3:7), the structure is more complex in its original state, and the interaction between particles is more prominent after pyrolysis.

[0068] like Figure 9 In the 7:3 mixture of tailings sand and corn stalks, the tailings sand particles constitute the majority, with irregular shapes and slight surface undulations. The corn stalk biochar particles are relatively small, mainly distributed between the tailings sand particles, resulting in a loose overall structure with clear particle boundaries. After pyrolysis at 400℃ (b), the particle surface roughens, with the appearance of fine deposits, possibly new substances generated during pyrolysis. Some tailings sand and biochar particles begin to show signs of adhesion, with a slightly more compact structure than the original state, but still relatively loose overall, and the particle outlines are generally discernible. After pyrolysis at 800℃ (c), particle agglomeration is obvious, forming larger lumps with a rougher surface and a denser structure. High temperatures promote deep reaction and fusion of the tailings sand and corn stalk biochar, blurring the particle boundaries and improving overall structural stability.

[0069] In the 3:7 mixture of tailings sand and corn stalks (d), the corn stalk biochar particles constitute a large proportion and are densely distributed, encapsulating the tailings sand particles. The structure is complex and loose, while the biochar is fibrous or flaky, interwoven with the tailings sand particles. After pyrolysis at 400℃ (e), both the biochar and tailings sand particles undergo changes. The fibrous structure of the biochar partially shrinks, and fine particles adhere to its surface. Similar adhesions also appear on the surface of the tailings sand, increasing adhesion between the two and resulting in a more compact local structure. After pyrolysis at 800℃ (f), a large number of agglomerates are formed. These agglomerates are large in size with an uneven surface and a highly dense structure. The high temperature allows the biochar and tailings sand to interact fully, significantly altering their original morphologies and enhancing the overall structural stability.

[0070] As the pyrolysis temperature increases, the microstructure of mixed materials with different proportions changes, including particle agglomeration, surface roughening, and structural densification. The proportion of corn straw biochar has a significant impact; a higher proportion results in a more complex original structure, and the morphological changes of biochar after pyrolysis and the interaction between the two are more prominent.

[0071] ③XRD pattern Sample preparation: The sample materials (27 groups in total) were laid flat on the glass slide, and then flattened evenly with a spatula before testing.

[0072] X-ray diffraction analysis: like Figure 10 Throughout the carbonization process, as the pyrolysis temperature increased, the diffraction peaks gradually broadened while their intensity gradually decreased. The corn stalk raw material exhibited two significant diffraction peaks at 2θ of 16.25° and 22.00°. As the pyrolysis temperature continued to rise, the peaks at 2θ of 16.25° and 22.00° of the corn stalk biochar essentially disappeared, while a new diffraction peak appeared near 2θ of 28.25°, representing SiO2, which is mainly a mineral component of the corn stalk fermentation residue. Furthermore, potassium salt diffraction peaks appeared at 2θ of 28.25° and 40.52°. With increasing temperature, these two diffraction peaks first became sharper and then broadened, but the trend was not significant.

[0073] Analysis of the Influence of Pyrolysis Temperature on Diffraction Peaks - Broadening and Decreased Intensity: As the pyrolysis temperature increases, the diffraction peaks gradually broaden while their intensity gradually decreases. This is because during pyrolysis, high temperatures cause the chemical bonds within the corn stalks to break, intensifying the thermal motion of atoms and disrupting the original crystal structure, leading to a more disordered arrangement of atoms. This disorder causes the diffraction peaks to expand beyond the sharpness of the raw material, extending over a wider angular range. Simultaneously, the destruction of the crystal structure reduces the ordered regions capable of diffraction, resulting in decreased diffraction intensity. This phenomenon demonstrates that pyrolysis temperature is a crucial factor affecting the crystal structure of corn stalks; the higher the temperature, the more severe the damage to the crystal structure.

[0074] The diffraction peaks of the raw materials reflect the presence of specific crystalline structures within them; changes in diffraction peaks caused by pyrolysis indicate that high temperatures destroy the crystalline structure; the new SiO2 peaks indicate that pyrolysis makes the crystalline structure of the mineral components more visible or obvious; changes in the diffraction peaks of potassium salts show that their structure changes during pyrolysis but remains relatively stable.

[0075] like Figure 11 Throughout the carbonization process, as the pyrolysis temperature increased, the diffraction peaks gradually broadened while their intensity gradually decreased. The rice straw biochar raw material exhibited two significant diffraction peaks at 2θ of 14.93° and 22.00°. When the pyrolysis temperature increased, the peaks at 2θ of 14.93° and 22.00° essentially disappeared, while new diffraction peaks appeared near 2θ of 24.35°, 26.47°, and 26.30°, possibly containing mineral components such as SiO2. Furthermore, new diffraction peaks appeared at 2θ of 21.72° and 26.65°. With increasing temperature, these diffraction peaks first became sharp and then broadened, but the trend was not significant. The diffraction peaks of the raw material indicate the presence of specific crystalline structures within it. The disappearance of the original diffraction peaks due to increased pyrolysis temperature suggests that high temperatures disrupted the crystalline structure of the rice straw biochar raw material. The appearance of new diffraction peaks may be due to changes in the material structure during pyrolysis, with the crystal structures of some mineral components, such as SiO2, becoming more apparent or more obvious.

[0076] like Figure 12 Throughout the process, the diffraction peaks changed with increasing pyrolysis temperature. The tailings raw material exhibited significant diffraction peaks at 2θ values ​​of 10.56°, 28.52°, and 31.86°. With increasing pyrolysis temperature, the position of the peak at 2θ of 10.56° changed slightly, becoming 10.45° at 400°C and 10.50° at 800°C; the peak near 2θ of 28.52° persisted at different temperatures, becoming 28.47° at 400°C and 28.52° at 800°C; the peak at 31.86° disappeared after pyrolysis. Furthermore, new diffraction peaks appeared near 2θ values ​​of 27.15° (400°C) and 27.21° (800°C). The diffraction peaks of the raw material indicate that the tailings sand possesses a specific crystal structure and mineral composition. The shift in the position of some diffraction peaks due to changes in pyrolysis temperature may be due to minor changes in the crystal structure or adjustments in interatomic spacing caused by temperature. The disappearance of the 31.86° diffraction peak indicates that the pyrolysis process altered the crystal structure of the corresponding mineral component or caused the mineral to decompose. The appearance of a new diffraction peak may be due to the formation of a new mineral phase or a transformation of the crystal structure of the original mineral phase during pyrolysis.

[0077] like Figure 13Throughout the carbonization process, the diffraction peaks changed with increasing pyrolysis temperature. The raw material, a 7:3 mixture of tailings sand and rice straw, exhibited significant diffraction peaks at 2θ of 10.56° and 28.47°. When the pyrolysis temperature increased to 400°C, the peak position at 10.56° remained unchanged, while 28.47° changed to 28.52°, and a new diffraction peak appeared near 27.26°. When the pyrolysis temperature increased to 500°C, 10.56° changed to 10.67°, 28.52° changed to 28.69°, and the peak near 27.26° disappeared. This indicates that the crystal structure underwent further changes at higher temperatures, possibly involving mineral phase decomposition, phase transformation, or recrystallization.

[0078] like Figure 14 Throughout the carbonization process, the diffraction peaks changed with increasing pyrolysis temperature. The raw material, a 7:3 mixture of tailings sand and corn stalks, exhibited significant diffraction peaks at 2θ of 10.50° and 28.47°. At 400°C, 10.50° shifted to 10.39°, while 28.47° remained unchanged. At 800°C, 10.39° returned to 10.50°, and 28.47° changed to 28.58°. The shift in the position of some diffraction peaks at 400°C may be due to minor changes in the interatomic spacing or crystal structure caused by pyrolysis. The change in peak position and intensity at 800°C indicates that the high temperature further altered the crystal structure and mineral composition of the material. The adsorption and catalytic properties of the mixed raw material may vary with the pyrolysis temperature.

[0079] like Figure 15 Throughout the carbonization process, the diffraction peaks changed with increasing pyrolysis temperature. The raw material, a 5:5 mixture of tailings sand and rice straw, exhibited significant diffraction peaks at 2θ of 10.39°, 28.41°, and 33.01°. When the pyrolysis temperature increased to 400°C, 10.39° became 10.61°, 28.41° became 28.63°, and the 33.01° peak disappeared. When the pyrolysis temperature increased to 800°C, 10.61° became 10.56°, and 28.63° became 28.58°. The diffraction peaks of the raw material reflect its internal mineral composition and crystal structure characteristics. The change in pyrolysis temperature leading to changes in the position and intensity of the diffraction peaks indicates that the pyrolysis process affected the crystal structure of the mixture. The shift in the position of some diffraction peaks and the disappearance of one peak at 400℃ may be due to changes in the interatomic distance or crystal structure inside the material caused by pyrolysis, leading to the transformation or decomposition of certain mineral phases. The change in the position of the diffraction peaks at 800℃ indicates that the high temperature further altered the crystal structure and mineral composition of the material.

[0080] like Figure 16Throughout the carbonization process, the diffraction peaks changed with increasing pyrolysis temperature. The raw material, a 5:5 mixture of tailings sand and corn stalks, exhibited significant diffraction peaks at 2θ of 10.56°, 28.47°, and 33.01°. When the pyrolysis temperature increased to 400°C, the peak at 10.56° changed to 10.45°, 28.47° to 28.41°, and the peak at 33.01° disappeared. When the pyrolysis temperature increased to 800°C, the peaks at 10.45° changed to 10.50°, and 28.41° to 28.58°. XRD pattern analysis of the 5:5 tailings sand and corn stalk mixture after different temperature treatments revealed a significant impact of temperature on the crystal structure of the mixture. As the temperature increased from the raw material state to [other conditions], the mineral phases in the mixture underwent continuous changes, including adjustments in interplanar spacing, phase transformations, and the decomposition and formation of mineral phases. These changes are significant for the properties and potential applications of the mixture.

[0081] like Figure 17 Throughout the carbonization process, the diffraction peaks changed with increasing pyrolysis temperature. The raw material, a 3:7 mixture of tailings sand and rice straw, exhibited significant diffraction peaks at 2θ of 10.61° and 28.52°. When the pyrolysis temperature reached 400°C, the 10.61° peak remained unchanged, while the 28.52° peak changed to 28.58°, and a new diffraction peak appeared near 31.92°. When the pyrolysis temperature reached 800°C, the 10.61° peak changed back to 10.61° (the numerical value remained the same, but the peak shape may have changed), the 28.58° peak changed to 28.63°, and the 31.92° peak disappeared. The diffraction peak near 2θ of 28.52° was relatively strong in the raw material, and its position and intensity changed with increasing temperature, reflecting the evolution of the mineral phases. The diffraction peak at 2θ of 31.92° only appeared at 400°C, possibly related to the formation of new substances and subsequent changes. In summary, the pyrolysis temperature has a significant impact on the crystal structure of the mixed sample.

[0082] like Figure 18Throughout the carbonization process, the diffraction peaks changed with increasing pyrolysis temperature. The raw material, a 3:7 mixture of tailings sand and corn stalks, exhibited significant diffraction peaks at 2θ values ​​of 10.56°, 22.17°, and 28.58°. When the pyrolysis temperature reached 400°, the 10.56° peak changed to 10.50°, the 22.17° peak disappeared, and the 28.58° peak remained unchanged. When the pyrolysis temperature reached 800°, the 10.50° peak changed to 10.45°, the 28.58° peak changed to 28.52°, and a new diffraction peak appeared near 33.07°. The diffraction peak near 22.17° (in the raw material) was particularly prominent, possibly due to specific diffraction signals generated by the corn stalks or their mixture with tailings sand. Its origin may be related to the composition of the corn stalks (such as cellulose and lignin) and their form and structure in the mixture. As the temperature increased, this peak was no longer mentioned in the spectra after treatment at 400℃ and 800℃, possibly because the organic components of the corn stalks gradually decomposed or transformed during pyrolysis, causing the diffraction peak to disappear. The diffraction peak near 2θ 28.58° was stronger in the raw material and after treatment at 400℃, possibly a characteristic diffraction peak of a major mineral phase in the mixed sample, mainly contributed by mineral phases in the tailings sand, but the composition of the corn stalks may also have some influence on its position and intensity. As the temperature increased to 800℃, the peak position changed to 28.52°, indicating that the mineral phase underwent structural changes at high temperatures, and parameters such as interplanar spacing were adjusted.

[0083] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0084] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a carbon sequestration and soil amendment type soil amendment based on iron tailings sand, characterized by, Includes the following steps: S1. The iron tailings sand is ground using a ball mill and sieved to obtain iron tailings powder, which is then dried to constant weight. After the biomass material is naturally air-dried, it is crushed by a pulverizer, sieved to obtain biomass material powder, and then dried to constant weight. S2, mix biomass materials and iron tailings sand evenly in different proportions; S3, using a one-step pyrolysis method under set temperature conditions, slowly pyrolyzes iron tailings sand-biochar composite material to obtain a soil conditioner.

2. A method of preparing a carbon sequestration and soil fertility enhancing type soil amendment based on iron tailings sand according to claim 1, characterized by: The tailings sand has a pH of 7.8, and the mass percentages of each chemical component in the tailings sand are as follows: Iron oxide 6.01%, potassium oxide 7.43%, calcium oxide 6.06%, magnesium oxide 7.35%, the remainder being impurities.

3. The method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand according to claim 2, characterized in that: The iron tailings in S1 are ground, passed through a 100-mesh sieve, and dried at 80°C to constant weight.

4. The method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand according to claim 3, characterized in that: The biomass material in S1 is pulverized, passed through a 100-mesh sieve, and dried at 80°C to constant weight.

5. The method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand according to claim 4, characterized in that: The biomass materials include, but are not limited to, corn stalks or rice stalks.

6. The method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand according to claim 5, characterized in that: The mixing mass ratio of biomass material and iron tailings sand in S2 is 7:3, 5:5 or 3:

7.

7. The method for preparing a carbon sequestration and fertilization soil conditioner based on iron tailings sand according to claim 6, characterized in that: The temperature of the one-step pyrolysis method in S3 is 400℃ or 800℃.

8. A soil conditioner, characterized in that, The soil conditioner is prepared by the method described in any one of claims 1 to 7.

9. A method for evaluating the soil conditioner as described in claim 8, characterized in that, Includes the following steps: S1, take soil with excessive heavy metals, add soil conditioner in proportion, and mix thoroughly; Add an appropriate amount of deionized water to S2 to bring the soil moisture to 60% of field capacity. After equilibration for a period of time, measure the changes in the physical, chemical and biological properties of the soil before and after application.

10. An application of the soil conditioner as described in claim 8, characterized in that, The soil conditioner is used for soil improvement, to solve soil degradation problems, to achieve sustainable resource utilization, and to promote sustainable agricultural development.

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