Dolomite powder-containing charcoal multifunctional compound fertilizer as well as preparation method and application thereof

Abstract

The invention relates to the technical field of biochar multifunctional compound fertilizers, in particular to a dolomite powder-containing biochar multifunctional compound fertilizer as well as a preparation method and application thereof.The preparation method comprises the following steps: preparing sludge powder by adopting wine-making excess sludge as a raw material, mixing the sludge powder with straw powder to provide biomass components, adding potassium carbonate powder and dolomite powder, and mixing to obtain the dolomite powder-containing biochar multifunctional compound fertilizer. The method has the advantages that inorganic mineral components (ash) in the sludge can form framework structures under high-temperature pyrolysis, pore structures formed in pyrolysis procedures can be supported and fixed, collapse at high temperatures can be prevented, developed and stable pore structures can be assuredly formed, and the ash content and the calorific value can be synergistically complemented after the pepper straws and the sludge powder are mixed with one another; a large amount of volatile components are escaped, so that the porosity is increased; meanwhile, the potassium carbonate powder and the dolomite powder are added, so that a carbon skeleton of the biomass is reconstructed, richer micropores and mesopores are created, rich surface functional groups are introduced, rich elements such as calcium and magnesium are supplemented, and the improvement effect of the acidified soil is enhanced.

Description

Technical Field

[0001] This invention relates to the field of biochar multifunctional compound fertilizer technology, and particularly to biochar multifunctional compound fertilizer containing dolomite powder, its preparation method and application. Background Technology

[0002] Farmland protection is a major issue concerning the national economy and people's livelihood. In my country, soil characteristics are as follows: southern soils are acidic, while northern soils are alkaline. Soil acidification is characterized by a significant decrease in soil pH and a significant increase in exchangeable acids, becoming a major manifestation of soil degradation. Soil acidification leads to the loss of large amounts of nutrients and trace elements, soil compaction, and environmental problems such as heavy metal activation. Therefore, researching and improving acidified soils has become a focal point for those skilled in the art, resulting in a large body of technical literature.

[0003] For example, patent application number 201810275787.0 discloses a soil conditioner for acidified tea gardens, comprising biochar and alkaline additives. The alkaline additives are at least two of the following: phosphate rock powder, calcium magnesium phosphate fertilizer, dolomite powder, and wood ash. The biochar content is 58.25%–85.29%. This method uses biochar as the main raw material, supplemented with at least two of the following alkaline additives: calcium magnesium phosphate fertilizer, phosphate rock powder, wood ash, and dolomite powder. It utilizes the functional groups and alkaline components of biochar to neutralize acidic components in the soil, thereby alleviating soil acidification. Furthermore, by leveraging the large porosity and specific surface area of ​​biochar, and through its coupling and loading of alkaline additives, the conditioner's ability to adsorb hydrogen ions and complex active aluminum ions is further enhanced, thus improving its buffering capacity and long-lasting effect. The biochar is obtained from straw, which is crushed and then pyrolyzed in an oxygen-deficient environment at 400–800℃ for 1–2 hours, cooled, and then sieved.

[0004] For example, patent application number 202211119430.6 discloses a soil conditioner for mitigating soil acidification, its preparation method, and its application method, including biochar and fertilizer; the fertilizer is phosphate rock powder or calcium magnesium phosphate fertilizer; the mass ratio of biochar to fertilizer is 16-24:1-2. The main component of the conditioner is straw biochar, which is supplemented with calcium magnesium phosphate fertilizer or phosphate rock powder, wood ash, dolomite powder, etc. Calcium magnesium phosphate fertilizer, phosphate rock powder, and wood ash provide nutrients and basic ions lacking in red soil, while dolomite powder enhances the conditioner's pH-regulating ability. This allows the biochar to neutralize and alleviate soil acidity through its functional groups and alkaline components. It also acts as a carrier for other materials, adsorbing basic ions and other components through its high porosity, thus improving its ability to adsorb hydrogen ions and reduce active aluminum, further enhancing the conditioner's buffering capacity and long-lasting effect.

[0005] For example, patent number 201710823590.1 discloses a soil conditioner for tobacco fields, its preparation method, and its application. The raw materials for preparing the soil conditioner include the following components by weight: 40-70 parts modified tobacco straw biochar, 30-40 parts modified bentonite, 5-30 parts humic acid powder, 10-40 parts dolomite powder, 10-30 parts quicklime, 10-15 parts biochar, 5-15 parts sulfur, and 5-10 parts Bacillus subtilis HS5B5. This conditioner can significantly improve soil pH, soil structure, and physicochemical properties. It can effectively avoid the limitations on tobacco growth caused by unsuitable soil pH, improve soil fertility, promote tobacco root growth, increase tobacco growth and yield, and effectively limit the occurrence of common fungal diseases in tobacco fields. The addition of distiller's grains and calcium silicate powder further increases the organic matter and trace element content of the tobacco field, significantly improving tobacco leaf quality and yield.

[0006] For example, patent number 202210163552.9 discloses a soil conditioner and improvement process for acidic tea garden soil. The soil conditioner, by weight, is made from the following raw materials: 10-20 parts dolomite powder, 40-60 parts modified biochar, 5-10 parts humic acid, 5-10 parts earthworm castings, 5-10 parts organic fertilizer, 6-12 parts compound microbial agent, 3-8 parts nitrification inhibitor, and 10-15 parts lignin superabsorbent resin. This soil conditioner can effectively improve soil fertility and solve the problem of insufficient soil water retention, inhibiting the decrease in soil base saturation. Simultaneously, the provided soil improvement process can further alleviate soil acidification and improve the microenvironment of the root zone, thereby improving tea quality.

[0007] For example, patent application number 202410516625.7 discloses a soil conditioner, its preparation method, and its application in improving acidic soils. Using limestone, dolomite, apatite, biochar, phosphate-solubilizing bacteria, organic materials, and fillers as raw materials, limestone, dolomite, and apatite can effectively inhibit the accumulation of acidifying ions such as hydrogen and aluminum, increasing soil pH. Biochar and organic materials can improve the soil's organic storage capacity and physicochemical structure. Phosphate-solubilizing bacteria specifically enhance the ability to solubilize phosphorus and activate nutrients, improving the activity and availability of soil nutrients and enhancing plant utilization of nutrients. Utilizing the synergistic effect of these raw materials, the physicochemical properties of acidic soils can be effectively improved, soil pH increased, the content of essential plant nutrients such as calcium and magnesium increased, soil organic matter increased, and the soil's resilience, buffering capacity, and agricultural production potential enhanced.

[0008] It is evident that the treatment of acidified soil primarily involves adding soil conditioners to improve soil properties such as pH, nutrient replenishment, aeration, water retention, exchangeable acidity, and cation exchange capacity. This, in turn, enhances soil performance, increases crop yield and quality, ensures food security, and improves the soil's sustainable productivity. However, current soil conditioner technologies still fall short of production requirements, and the raw materials used are costly with limited effectiveness. Summary of the Invention

[0009] Based on the above-mentioned technical problems, the present invention provides a multifunctional compound fertilizer containing dolomite powder, its preparation method and application.

[0010] The specific technical solution is as follows:

[0011] One of the objectives of this invention is to provide a method for preparing a multifunctional compound fertilizer containing dolomite powder, comprising the following steps:

[0012] (1) After ultrasonic treatment, the remaining sludge from brewing is dried to constant weight, ground and passed through an 80-mesh sieve to obtain sludge powder; the straw is cleaned, dried, cut into sections, crushed and passed through an 80-mesh sieve to obtain straw powder.

[0013] (2) Mix sludge powder and straw powder at a mass ratio of 1:1-2 to obtain mixed powder; then add potassium carbonate powder accounting for 15-20% of the mass of mixed powder and dolomite powder accounting for 5-10% of the mass of mixed powder to the mixed powder, mix evenly to obtain mixed material;

[0014] (3) Place the mixture in a pyrolysis furnace and heat it to 700-800℃ under inert gas protection for 2-6 hours to obtain the final product.

[0015] Sludge powder was prepared using brewing waste sludge as raw material. The sludge powder was mixed with straw powder to provide biomass components. Potassium carbonate powder and dolomite powder were then added to the mixture. This allowed the inorganic mineral components (ash) in the sludge to form a framework structure under high-temperature pyrolysis, supporting and fixing the pore structure formed during pyrolysis, preventing collapse at high temperatures and ensuring a well-developed and stable pore structure. Simultaneously, the combination of chili straw and sludge powder resulted in synergistic complementarity in ash content and calorific value, allowing a large amount of volatile components to escape and increasing porosity. Furthermore, the addition of potassium carbonate and dolomite powder reconstructed the carbon skeleton of the biomass, creating richer micropores and mesopores, introducing abundant surface functional groups, and supplementing with calcium, magnesium, and other elements, thus enhancing the soil acidification improvement effect.

[0016] In order to homogenize the inorganic mineral components and organic matter components in the brewing waste sludge, thereby ensuring the formation of good pores and framework structure during subsequent pyrolysis and guaranteeing the overall multifunctional compound fertilizer's improvement effect on acidified soil, preferably, the ultrasonic treatment is performed in an ultrasonic processor with ultrasonic waves at a frequency of 20-60kHz for 10-15 minutes.

[0017] In certain operational schemes of this invention, the drying to constant weight is performed by drying at 105°C; and / or the drying and cutting is performed by drying at 60°C to constant weight.

[0018] Preferably, the mass ratio of the sludge powder to the straw powder is 1:1.5.

[0019] In the experiments described in this invention, the straw powder used was chili straw powder. However, those skilled in the art can use straw that is the same as or similar to the chili straw used in this invention as a substitute.

[0020] In the experimental design of this invention, the heating rate was 5°C / min. Alternatively, other more balanced and gentle biological methods can be used, as long as they avoid the defects of excessively rapid evaporation of volatile components leading to damage to the skeletal structure, and also avoid excessively slow heating rates leading to unsatisfactory pore formation.

[0021] The brewing waste sludge used in the experimental design of this invention had a moisture content of 99.21%, a pH of 7.63, and a density of 1.01 g / cm³. 3 The zeta potential is -27.2 mV. This characteristic of brewing waste sludge is closely related to the process parameters in its preparation method.

[0022] The second objective of this invention is to provide a multifunctional compound fertilizer containing dolomite powder prepared by the above method.

[0023] The third objective of this invention is to provide the application of the above-mentioned biochar multifunctional compound fertilizer containing dolomite powder in the improvement of acidic soil.

[0024] Preferably, the biochar multifunctional compound fertilizer containing dolomite powder is added to the soil at a rate of 8-16g per kilogram of soil and then mixed evenly.

[0025] Compared with the prior art, the technical effects of this invention are reflected in:

[0026] This invention uses brewing waste sludge as raw material and adds chili straw, so that the ash and calorific value of the brewing waste sludge and chili straw complement each other. With the addition of dolomite powder and potassium carbonate, the pyrolysis process promotes the formation of biochar multifunctional compound fertilizer with rich pore structure. It makes full use of the sludge components and agricultural waste straw generated by the brewing industry. It is low in cost, environmentally friendly, and can reduce the cost of brewing waste sludge treatment and improve the economic benefits of the brewing industry.

[0027] The invention creates a simple, easy-to-control, and easily industrialized process for preparing multifunctional biochar compound fertilizer, enabling large-scale production and conforming to the concept of sustainable industrial development. Attached Figure Description

[0028] In order to enable those skilled in the art to fully understand the technical solution of the present invention, the following description is made in conjunction with the technical solution content and the accompanying drawings.

[0029] Figure 1 A process flow diagram is provided for this invention.

[0030] Figure 2 The image shows anhydrous potassium carbonate powder purchased from the market, which was used in the creation of this invention.

[0031] Figure 3 Photographs of the brewing waste sludge collected for this invention.

[0032] Figure 4 for Figure 3 Photo of sludge powder after it has been dried.

[0033] Figure 5 Photographs of dolomite powder used in this invention and purchased from the market.

[0034] Figure 6 Photograph of the chili straw powder used in this invention.

[0035] Figure 7 Photograph of the multifunctional compound fertilizer sample obtained in Example 1 of this invention.

[0036] Figure 8 The XRD characterization diagram of the multifunctional compound fertilizer obtained in Example 1 of this invention.

[0037] Figure 9 The SEM characterization image of the multifunctional compound fertilizer obtained in Example 1 of this invention.

[0038] Figure 10 The BET characterization diagram of the multifunctional compound fertilizer obtained in Example 1 of this invention. Detailed Implementation

[0039] To facilitate a correct understanding of the present invention by those skilled in the art, and to enable them to fully understand the technical content of the present invention, the technical solution of the present invention will be further described below in conjunction with specific embodiments. However, this description does not limit the scope of protection claimed by the present invention. Those skilled in the art should not limit the scope of protection of the present invention to the following description. Any equivalent substitutions or changes made by those skilled in the art or those familiar with the art based on the present invention, and based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0040] like Figure 1 As shown, in some embodiments, the preparation method of biochar multifunctional compound fertilizer containing dolomite powder includes the following steps:

[0041] (1) As follows Figure 3 The brewing waste sludge shown was treated with ultrasound in an ultrasonic processor at frequencies of 20-60 kHz, such as 20 kHz, 25 kHz, 30 kHz, 40 kHz, 50 kHz, 60 kHz, etc., for 10-15 minutes, such as 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, or 15 minutes. Afterwards, it was dried at 105℃ to constant weight, ground, and passed through an 80-mesh sieve to obtain the following... Figure 4 The sludge powder shown is obtained by washing the straw, drying it (at 60°C), cutting it into sections, and crushing it through an 80-mesh sieve. Figure 6 The straw powder shown;

[0042] (2) Mix sludge powder and straw powder in a mass ratio of 1:1-2, for example: 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, etc., to obtain a mixed powder; then add 15-20% of the mass of the mixed powder, for example: 15%, 16%, 17%, 18%, 19%, 20%, etc. Figure 2 The potassium carbonate powder shown contains 5-10% of the mixed powder, for example: 5%, 6%, 7%, 8%, 9%, 10%, etc. Figure 5 The dolomite powder shown is mixed evenly to obtain a mixture.

[0043] (3) Place the mixture in a pyrolysis furnace and heat it at 5℃ / min to a temperature between 700-800℃ for 2-6 hours under inert gas protection, for example: 2h, 3h, 4h, 5h or 6h, etc.

[0044] In some embodiments, the straw powder is as follows: Figure 6The chili straw powder shown.

[0045] In some embodiments, the brewing waste sludge has a moisture content of 99.21%, a pH of 7.63, and a density of 1.01 g / cm³. 3 The Zeta potential is -27.2mV.

[0046] In order to better verify the technical effects that the present invention can bring, the researchers of the present invention conducted the following experimental studies.

[0047] Experiment 1: Performance Testing of Biochar Multifunctional Compound Fertilizer with Different Raw Material Components

[0048] 1. Sample preparation and detection of elemental content and specific surface area in samples.

[0049] Example 1

[0050] The leftover sludge from brewing was placed in an ultrasonic processor and treated with ultrasound at 40 kHz for 10 minutes. It was then dried at 105℃ to constant weight, ground, and passed through an 80-mesh sieve to obtain sludge powder. Chili stalks were cleaned, dried (at 60℃), cut into sections, crushed, and passed through an 80-mesh sieve to obtain chili stalk powder. The sludge powder and chili stalk powder were mixed at a mass ratio of 1:2 to obtain a mixed powder. Potassium carbonate powder (15% by mass) and dolomite powder (8% by mass) were added to the mixed powder and mixed evenly to obtain a mixture. The mixture was placed in a pyrolysis furnace and, under inert gas (nitrogen) protection, heated at 5℃ / min to a temperature between 700-800℃ and held for 2 hours to obtain biochar multifunctional compound fertilizer.

[0051] The biochar multifunctional compound fertilizer obtained in Example 1 was characterized by X-ray fluorescence, and the contents of Mg, Ca, K, P, Si, S, Ti, Mn, Fe, Ni, Zn, and Sr are shown in Table 1 below:

[0052] Table 1 (mass%)

[0053]

[0054] The biochar multifunctional compound fertilizer obtained in Example 1 had a specific surface area of ​​489.0 m² / g as measured by BET.

[0055] Example 2

[0056] Based on Example 1, the sludge powder was replaced with an equal mass of chili straw powder, and all other aspects were the same as in Example 1.

[0057] The biochar multifunctional compound fertilizer obtained in Example 2 was characterized by X-ray fluorescence, and the contents of Mg, Ca, K, P, Si, S, Ti, Mn, Fe, Ni, Zn, and Sr are shown in Table 2 below:

[0058] Table 2 (mass%)

[0059] Mg Ca K P Si S 3.645 8.012 5.29 1.45 6.023 0.414 Ti Mn Fe Ni Zn Sr 0.17 0.125 0.043 0.056 0.021 0.041

[0060] The biochar multifunctional compound fertilizer obtained in Example 2 had a specific surface area of ​​465.2 m² / g as measured by BET.

[0061] Example 3

[0062] Based on Example 1, the chili straw powder was replaced with an equal mass of sludge powder, while all other aspects remained the same as in Example 1.

[0063] The biochar multifunctional compound fertilizer obtained in Example 3 was characterized by X-ray fluorescence, and the contents of Mg, Ca, K, P, Si, S, Ti, Mn, Fe, Ni, Zn, and Sr are shown in Table 3 below:

[0064] Table 3 (mass%)

[0065]

[0066] The biochar multifunctional compound fertilizer obtained in Example 3 had a specific surface area of ​​378.4 m² / g as measured by BET.

[0067] Example 4

[0068] Based on Example 1, potassium carbonate powder was replaced with an equal mass of dolomite powder, and everything else was the same as in Example 1.

[0069] The biochar multifunctional compound fertilizer obtained in Example 4 was characterized by X-ray fluorescence, and the contents of Mg, Ca, K, P, Si, S, Ti, Mn, Fe, Ni, Zn, and Sr are shown in Table 4 below:

[0070] Table 4 (mass%)

[0071] Mg Ca K P Si S 5.027 10.33 3.99 3.01 6.92 0.50 Ti Mn Fe Ni Zn Sr 0.313 0.242 0.857 0.052 0.047 0.050

[0072] The biochar multifunctional compound fertilizer obtained in Example 4 had a specific surface area of ​​67.6 m² / g as measured by BET.

[0073] Example 5

[0074] Based on Example 1, the dolomite powder was replaced with an equal mass of potassium carbonate powder, and everything else was the same as in Example 1.

[0075] The biochar multifunctional compound fertilizer obtained in Example 5 was characterized by X-ray fluorescence, and the contents of Mg, Ca, K, P, Si, S, Ti, Mn, Fe, Ni, Zn, and Sr are shown in Table 5 below:

[0076] Table 5 (mass%)

[0077]

[0078] The biochar multifunctional compound fertilizer obtained in Example 5 had a specific surface area of ​​487.2 m² / g as measured by BET.

[0079] 2. The samples were used for testing the soil acidification improvement capacity.

[0080] The biochar multifunctional compound fertilizers obtained in Examples 1 to 5 were used to improve the acidic soil that had developed during long-term tea garden cultivation. The treatment method during the experiment was as follows:

[0081] Soil samples were collected from a tea garden in Zunyi City, Guizhou Province (where tea trees have been planted for 10 years). The soil samples were collected at depths ranging from 0 cm to 25 cm from the surface to the inner soil layer. The pH, exchangeable acidity, and cation exchange capacity of the soil were measured. The results were: pH 4.24, exchangeable acidity 6.97 cmol / kg, and cation exchange capacity 37.2 cmol / kg. Three sets of experiments were conducted for each example. 150 g of the soil was weighed, and 10 g of biochar multifunctional compound fertilizer was added per kilogram of soil. After mixing thoroughly, the mixture was placed in a constant temperature and humidity environment (25°C, 70%) for 60 days. The pH, exchangeable acidity, and cation exchange capacity of the improved soil were then measured. The results are shown in Table 6 below.

[0082] Table 6

[0083]

[0084] Table 6 shows that different raw material compositions lead to significant differences in the soil improvement effect of the resulting biochar multifunctional compound fertilizer. The sample prepared using Example 1 can increase the pH value of acidified soil in tea gardens to about 5.18, reduce the exchangeable acidity to 5.11 cmol / kg, and increase the cation exchange capacity to 39.8 cmol / kg. Therefore, the raw material composition of brewing waste sludge, chili straw, potassium carbonate powder, and dolomite powder are indispensable. The interaction between the raw materials enhances the ability of biochar multifunctional compound fertilizer to improve acidified soil.

[0085] When using the aforementioned biochar multifunctional compound fertilizer for acidified soil improvement, it is simply added to the soil and mixed evenly. The method is simple and easy to operate. The dosage can be determined based on the soil properties. In the soil conditions described in this invention, the dosage of biochar multifunctional compound fertilizer can be controlled at 8-16g per kilogram of soil, which is sufficient for improving acidified soil.

[0086] Experiment 2: Study on the soil improvement capacity of biochar multifunctional compound fertilizer with different ratios of sludge powder and chili straw powder

[0087] 1. Sample preparation and detection of elemental content and specific surface area in samples.

[0088] Example 6

[0089] Based on Example 1, sludge powder and chili straw powder were mixed at a mass ratio of 1:0.5, and all other aspects were the same as in Example 1.

[0090] The biochar multifunctional compound fertilizer obtained in Example 6 was characterized by X-ray fluorescence, and the contents of Mg, Ca, K, P, Si, S, Ti, Mn, Fe, Ni, Zn, and Sr are shown in Table 7 below:

[0091] Table 7 (mass%)

[0092] Mg Ca K P Si S 3.32 8.02 4.99 3.16 5.84 0.55 Ti Mn Fe Ni Zn Sr 0.331 0.286 11.73 0.069 0.433 0.049

[0093] The biochar multifunctional compound fertilizer obtained in Example 6 had a specific surface area of ​​378 m² / g as measured by BET.

[0094] Example 7

[0095] Based on Example 1, sludge powder and chili straw powder were mixed at a mass ratio of 1:0.5, without the addition of potassium carbonate and dolomite powder, and all other aspects were the same as in Example 1.

[0096] The biochar multifunctional compound fertilizer obtained in Example 7 was characterized by X-ray fluorescence, and the contents of Mg, Ca, K, P, Si, S, Ti, Mn, Fe, Ni, Zn, and Sr are shown in Table 8 below:

[0097] Table 8 (mass%)

[0098] Mg Ca K P Si S 0.67 0.91 3.05 3.46 5.99 0.59 Ti Mn Fe Ni Zn Sr 0.34 0.297 12.356 0.074 0.444 0.050

[0099] The biochar multifunctional compound fertilizer obtained in Example 7 had a specific surface area of ​​89.0 m² / g as measured by BET.

[0100] Example 8

[0101] Based on Example 1, sludge powder and chili straw powder were mixed at a mass ratio of 1:1, and all other aspects were the same as in Example 1.

[0102] The biochar multifunctional compound fertilizer obtained in Example 8 was characterized by X-ray fluorescence, and the contents of Mg, Ca, K, P, Si, S, Ti, Mn, Fe, Ni, Zn, and Sr are shown in Table 9 below:

[0103] Table 9 (mass%)

[0104] Mg Ca K P Si S 3.41 8.23 5.77 3.78 6.79 0.501 Ti Mn Fe Ni Zn Sr 0.332 0.284 0.976 0.046 0.057 0.051

[0105] The biochar multifunctional compound fertilizer obtained in Example 8 had a specific surface area of ​​475.0 m² / g as measured by BET.

[0106] Example 9

[0107] Based on Example 1, sludge powder and chili straw powder were mixed at a mass ratio of 1:1.5, and all other aspects were the same as in Example 1.

[0108] The biochar multifunctional compound fertilizer obtained in Example 9 was characterized by X-ray fluorescence, and the contents of Mg, Ca, K, P, Si, S, Ti, Mn, Fe, Ni, Zn, and Sr are shown in Table 10 below:

[0109] Table 10 (mass%)

[0110]

[0111] The biochar multifunctional compound fertilizer obtained in Example 9 had a specific surface area of ​​484.5 m² / g as measured by BET.

[0112] Example 10

[0113] Based on Example 1, sludge powder and chili straw powder were mixed at a mass ratio of 1:2.5, with all other aspects remaining the same as in Example 1.

[0114] The biochar multifunctional compound fertilizer obtained in Example 10 was characterized by X-ray fluorescence, and the contents of Mg, Ca, K, P, Si, S, Ti, Mn, Fe, Ni, Zn, and Sr are shown in Table 11 below:

[0115] Table 11 (mass%)

[0116] Mg Ca K P Si S 3.11 8.07 5.89 2.77 5.7 0.5 Ti Mn Fe Ni Zn Sr 0.11 0.09 0.902 0.031 0.029 0.048

[0117] The biochar multifunctional compound fertilizer obtained in Example 10 had a specific surface area of ​​471.9 m² / g as measured by BET.

[0118] Example 11

[0119] Based on Example 1, sludge powder and chili straw powder were mixed at a mass ratio of 1:2.5, without the addition of potassium carbonate and dolomite powder, and all other aspects were the same as in Example 1.

[0120] The biochar multifunctional compound fertilizer obtained in Example 11 was characterized by X-ray fluorescence, and the contents of Mg, Ca, K, P, Si, S, Ti, Mn, Fe, Ni, Zn, and Sr are shown in Table 12 below:

[0121] Table 12 (mass%)

[0122]

[0123] The biochar multifunctional compound fertilizer obtained in Example 11 had a specific surface area of ​​101.0 m² / g as measured by BET.

[0124] 2. The samples were used for testing the soil acidification improvement capacity.

[0125] The biochar multifunctional compound fertilizers obtained in Examples 6 to 11 were used in an acidified soil improvement experiment according to Experiment 1. The pH value, exchangeable acidity, and cation exchange capacity of the improved soil were measured, and the results are shown in Table 13 below:

[0126] Table 3

[0127]

[0128] Table 13 shows that changes in the mass ratio of sludge powder to chili straw powder will affect the soil improvement capacity of biochar multifunctional compound fertilizer. When the amount of sludge powder is greater than that of chili straw powder, the exchangeable acidity in the improved soil will be higher, the pH will be lower, and the cation exchange capacity will be lower compared to when the amount of sludge powder is equal to or less than that of chili straw powder, resulting in poor improvement effect. When the amount of chili straw powder is 2.5 times the mass of sludge powder, it will lead to a decrease in pH and a decrease in cation exchange capacity, resulting in a worse improvement effect. Therefore, the mass ratio of sludge powder to chili straw powder should be controlled at 1:1-2 for better results.

[0129] Meanwhile, as shown in Tables 1 to 5 and Tables 7 to 12, the P content in the biochar multifunctional compound fertilizers obtained in Examples 2, 10, and 11 is relatively low; the Ca and Mg content in the biochar multifunctional compound fertilizers obtained in Examples 5, 7, and 10 is relatively low; the BET specific surface area of ​​the biochar multifunctional compound fertilizer obtained in Example 4 is relatively low, even below 70 m² / g; and the Fe content in the biochar multifunctional compound fertilizers obtained in Examples 3 and 7 is relatively high. According to existing technologies, “Briat, JF, Dubos, C., & Gaymard, F. (2015). Iron nutrition, biomass production, and plant product quality. Trends in Plant Science, 20(1), 33–40.” and “Hänsch, R., & Mendel, RR (2009). Physiological functions of mineral micronutrients (Cu,Zn, Mn, Fe, Ni, Mo, B, Cl). Current Opinion in Plant Biology, 12(3)”,… As described in references such as "259–266." and "Müller, C., Kuki, KN, Pinheiro, DT, de Souza, LR, Siqueira, AS, & Oliva, MA (2015). Differential tolerance to iron toxicity in ricecultivars. Journal of Plant Nutrition, 38(6), 923–935.", higher iron content can cause oxidative stress, nutrient imbalance, growth retardation, and physiological metabolic disorders in plants. Therefore, a higher Fe content will make the resulting biochar multifunctional compound fertilizer unsuitable for the treatment of acidified soil.

[0130] For any other matters not covered in this invention, they can be addressed by referring to existing technologies or common knowledge known to those skilled in the art, and by using conventional technical means.

Claims

1. A method for preparing a biochar multifunctional compound fertilizer containing dolomite powder, characterized in that, The method comprises the following steps: (1) drying the wine-making residual sludge to constant weight after ultrasonic treatment, grinding and passing through an 80-mesh sieve to obtain sludge powder; cleaning and drying the straw, cutting and grinding to pass through an 80-mesh sieve to obtain straw powder; (2) mixing the sludge powder and the straw powder at a mass ratio of 1:1-2 to obtain mixed powder, adding 15-20% of potassium carbonate powder and 5-10% of dolomite powder to the mixed powder, and mixing uniformly to obtain a mixture; (3) placing the mixture in a pyrolysis furnace, and pyrolyzing at 700-800 ℃ for 2-6 h under the protection of inert gas.

2. The method of claim 1, wherein, The ultrasonic treatment is performed in an ultrasonic processor for 10-15 min by using ultrasonic waves with a frequency of 20-60 kHz.

3. The method of claim 1, wherein, The drying to constant weight is performed at 105 ℃, and / or the drying and cutting are performed at 60 ℃.

4. The method of claim 1, wherein, The mass ratio of the sludge powder to the straw powder is 1:1.

5.

5. The method of claim 1 or 4, wherein, The straw powder is pepper straw powder.

6. The method of claim 1, wherein, The heating rate of the heating is 5 ℃ / min.

7. The method of claim 1, wherein, The water content of the brewing residual sludge was 99.21%, the pH was 7.63, the density was 1.01 g / cm 3 , and the Zeta potential was -27.2 mV.

8. The dolomite powder-containing biochar multifunctional composite fertilizer prepared by the method according to any one of claims 1-7.

9. The use of the dolomite powder-containing biochar composite material prepared by the method according to any one of claims 1-7 or the dolomite powder-containing biochar multifunctional composite fertilizer according to claim 8 in acid soil improvement.

10. The use according to claim 9, wherein the compound is ###00003### or a pharmaceutically acceptable salt thereof. The dolomite powder-containing biochar multifunctional composite fertilizer is mixed uniformly in the soil at 8-16 g per kg of soil.

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