Method for preparing regenerated soil from ardealite and application thereof

Abstract

The invention provides a method for preparing regenerated soil by utilizing ardealite and application thereof, the method takes bulk solid waste ardealite as a raw material, and the regenerated soil with high fertility, stable structure and strong water and fertilizer retention capability is obtained by performing harmless and microorganism alternative fermentation and trace element compounding treatment on the bulk solid waste ardealite, and can be directly used for crop planting. According to the method, plant absorption of Ca, S, P and other elements in the phosphogypsum can be promoted, and land utilization of all components of the phosphogypsum is achieved. Besides, an organic-inorganic complex is formed through a compatible fermentation technology, the complex can promote formation of a soil aggregate structure and can improve the bio-availability of microelements in the soil and the stability of organic matter, and then high-quality regenerated soil with high water retention and air permeability and lasting fertilizer efficiency is constructed. According to the method, the problem of phosphogypsum stockpiling can be effectively solved, the prepared regenerated soil can be applied to cultivated land improvement, land reclamation and crop planting, and the purpose of turning waste into wealth is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of solid waste resource utilization, and in particular relates to a method for preparing regenerated soil by utilizing phosphogypsum and application thereof. Background Art

[0002] Phosphogypsum is a byproduct of the wet process of producing phosphoric acid. Every ton of phosphoric acid produced will produce 4-5 tons of phosphogypsum. Phosphogypsum has become one of the major industrial solid wastes in my country. The main component of phosphogypsum is CaSO4·2H2O, and it also includes acid insoluble matter, a small amount of phosphoric acid, phosphate, fluoride and unreacted phosphate rock. At present, the main treatment method for phosphogypsum in my country is storage. This treatment method not only occupies a large area, but also the leakage liquid containing P, F and other elements released by the phosphogypsum storage will enter the water body with precipitation, causing harm to the ecosystem of rivers, lakes and seas. Therefore, the comprehensive utilization of phosphogypsum waste residue is crucial to the sustainable development of the phosphorus chemical industry. Phosphogypsum contains important nutrients such as phosphorus, sulfur, calcium, silicon, magnesium and iron required for crop growth. Converting it into soil for reuse can realize large-scale consumption of phosphogypsum resources. However, phosphogypsum usually contains harmful impurities such as heavy metals, free fluorine and organic matter, which makes phosphogypsum cannot be directly used for land. In addition, the solubility of calcium sulfate dihydrate in phosphogypsum is low in water, and the phosphorus element mainly exists in the form of insoluble phosphorus such as phosphate precipitates, undecomposed phosphate rock powder and eutectic phosphorus, which makes elements such as Ca, S and P difficult to be absorbed and utilized by plants.

[0003] Therefore, a new method that can achieve harmless and efficient utilization of all components of phosphogypsum is urgently needed to promote the large-scale application of phosphogypsum in the soil field. Summary of the invention

[0004] In order to solve the problems in the background technology, the present invention provides a method for preparing regenerated soil using phosphogypsum and its application, which can effectively remove toxic and harmful elements in phosphogypsum and fully release the nutrient elements required by plants such as Ca, S, P, etc., thereby realizing the efficient and safe application of phosphogypsum in the soil field.

[0005] Another object of the present invention is to provide a regenerated soil with high fertility, stable structure and strong water and fertilizer retention capacity. The regenerated soil is rich in various nutrients required for plant growth, and has good water retention and air permeability, which can effectively improve soil structure and promote plant growth.

[0006] Another object of the present invention is to provide an application of a method for preparing regenerated soil using phosphogypsum.

[0007] The present invention adopts the following technical solution: A method for preparing regenerated soil using phosphogypsum comprises the following steps: Step S1. The phosphogypsum and the organic acid solution with a molar concentration of 0.1-1 mol / L are fully mixed and reacted for 1-24 h, washed with water and dried to obtain modified phosphogypsum.

[0008] Step S2. The modified phosphogypsum, clay mineral, microbial agent and organic matter in step S1 are uniformly mixed in a certain proportion by a step-by-step mixing method, and then transferred into a fermentation device. By changing the atmosphere in the fermentation device, aerobic-anaerobic alternating microbial fermentation is carried out to obtain fermented phosphogypsum rich in organic matter.

[0009] Step S3. Add a trace element compounding agent to the fermented phosphogypsum in step S2, mix them evenly, and obtain regenerated soil.

[0010] Further, the organic acid in step S1 is an organic acid with strong ability to complex heavy metals, preferably, one or more of oxalic acid, ethylenediaminetetraacetic acid, citric acid, formic acid, acetic acid, propionic acid, lactic acid, succinic acid, malonic acid, maleic acid, tartaric acid, succinic acid, malic acid, benzoic acid, phenylacetic acid, phthalic acid, terephthalic acid, valeric acid, caproic acid, capric acid, stearic acid, and acrylic acid; Furthermore, the goal of the reaction between phosphogypsum and organic acid in step S1 is to make the element content in phosphogypsum comply with the national standard "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)" (GB15618-2018).

[0011] Furthermore, the clay mineral in step S2 is one or more of montmorillonite, kaolinite, halloysite, palygorskite, sepiolite, illite, talc, sericite, and vermiculite.

[0012] Furthermore, the microbial agent in step S2 is a mixture of yeast agents, actinomycetes agents, lactic acid bacteria agents, sulfate-reducing bacteria, phosphate-solubilizing bacteria, nitrogen-fixing bacteria and potassium-solubilizing bacteria.

[0013] Furthermore, the organic matter in step S2 is one or more of livestock and poultry manure, livestock and poultry carcasses, kitchen waste, biogas residue, mushroom residue, urban sludge, and crop straw, and the element content thereof complies with the national standard "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)" (GB15618-2018).

[0014] Furthermore, the step-by-step mixing method in step S2 is to firstly mix the organic matter, clay mineral and microbial agent in a mass ratio of 1:0.01-0.2:0.01-0.1 to obtain a primary mixed material, and then uniformly mix the modified phosphogypsum and the primary mixed material in a mass ratio of 1:0.1-0.6, and control the water content of the mixed material to be 60%.

[0015] Furthermore, the aerobic-anaerobic alternating microbial fermentation in step S2 is to perform aerobic fermentation on the mixed materials and then perform anaerobic fermentation, and the process is repeated several times.

[0016] The aerobic fermentation is carried out by microorganisms in an air atmosphere, the gaseous oxygen content in the fermentation device is controlled at 5-21 Vol%, and the fermentation time is 4-20 days.

[0017] The anaerobic fermentation is carried out by introducing nitrogen atmosphere into the fermentation bottle, controlling the gaseous oxygen content in the fermentation device to be lower than 5 Vol%, and the fermentation time is 3-15 days.

[0018] The number of aerobic-anaerobic alternating fermentations is 1-10 times.

[0019] Furthermore, the trace element compounding agent in step S3 is a natural mineral conditioning material or an inorganic reagent.

[0020] Furthermore, the natural mineral conditioning material is one or more of feldspar, mica, hornblende, pyroxene, olivine, garnet, dolomite, allophane, and iron oxide.

[0021] Furthermore, the inorganic reagent is one or more of ammonium sulfate, zinc sulfate, magnesium sulfate, borax and calcium nitrate.

[0022] Furthermore, the amount of the trace element compounding agent added in step S3 accounts for less than 10% of the total mass.

[0023] A regenerated soil prepared by using phosphogypsum is prepared by using the above-mentioned preparation method.

[0024] Furthermore, the regenerated soil can be applied in the field of crop planting.

[0025] Beneficial effects of the present invention: (1) The present invention uses bulk solid waste phosphogypsum as raw material, removes heavy metals, free fluorine and other harmful substances therein by pickling through organic acid adsorption, complexation and other methods, and achieves harmless treatment. Then, through alternating fermentation of aerobic and anaerobic microorganisms and compound treatment of trace elements, a regenerated soil with high fertility, stable structure and strong water and fertilizer retention capacity is obtained. This method can not only effectively solve the problem of phosphogypsum storage, but also apply the obtained regenerated soil to farmland improvement, soil reclamation and crop planting, achieving the goal of turning waste into treasure.

[0026] (2) The clay mineral-organic matter-phosphogypsum mixture is fermented by aerobic-anaerobic alternating microbial fermentation. This method can effectively promote the release of Ca, S and P elements in phosphogypsum and improve soil fertility. In addition, the use of organic-inorganic fermentation helps to form an organic-inorganic complex, which can not only promote the formation of aggregate structure in the soil and improve the soil structure, but also improve the stability of organic matter in the soil, thereby constructing high-quality regenerated soil with strong water retention and air permeability, high fertility and long-lasting fertilizer effect. At the same time, the high temperature environment generated during the fermentation process can effectively eliminate pathogens and parasite eggs, thereby avoiding pests and ensuring the biological safety of the regenerated soil.

[0027] (3) The prepared regenerated soil can be used directly for crop planting without the need to mix with other fertilizers. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a photo of the regenerated soil of the product prepared in Example 1 of the present invention; Figure 2 It is a schematic diagram of the method for preparing regenerated soil based on phosphogypsum of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The preparation methods of Examples 1 to 6 can all be referenced Figure 2 .

[0031] Example 1 A method for preparing regenerated soil using phosphogypsum comprises the following steps: 1) Take 5 kg of phosphogypsum and 10 L of 0.1 mol / L oxalic acid solution, mix them thoroughly, react for 12 h, wash with ultrapure water and dry to obtain modified phosphogypsum.

[0032] 2) Take 9kg of straw powder, 1kg of cow dung, 100g of kaolin, and 100g of microbial agent and mix them evenly to obtain a primary mixed material. Then take 5kg of modified phosphogypsum and 1kg of the primary mixed material and mix them evenly. The water content of the mixed material is controlled at about 60%. Then transfer it to an anaerobic bottle, and control the gaseous oxygen content in the fermentation bottle to 20Vol%. Ferment for 10 days; then introduce nitrogen into the anaerobic bottle, and control the gaseous oxygen content in the fermentation bottle to below 5Vol%. Ferment for 4 days to obtain fermented phosphogypsum rich in organic matter. Ferment once alternately.

[0033] 3) Add 1% by weight (total weight) of magnesium sulfate and zinc sulfate composite conditioning materials to the fermented phosphogypsum system, mix them evenly, and obtain regenerated soil.

[0034] The prepared regenerated soil is brown and has a loose texture (e.g. Figure 1 The soil bulk density is 1.3 g / cm 3 , pH value 6.5, conductivity 2.37mS / cm, organic matter content 30g / kg, available phosphorus content 565mg / kg, available potassium content 2620mg / kg, alkaline nitrogen content 303mg / kg, available calcium content 378mg / kg, available magnesium content 35 mg / kg, and available sulfur content 15 mg / kg. According to the nutrient classification standard of the second national soil census, the nutrients of the regenerated soil belong to Class I. In addition, the contents of heavy metals such as Hg, Cd, As, Pb, Cr, Cu, and Ni in the soil are all lower than the screening values ​​of the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)" (GB15618-2018), which meets the standards for composite agricultural land.

[0035] Example 2 A method for preparing regenerated soil using phosphogypsum comprises the following steps: 1) Take 5 kg of phosphogypsum and 10 L of 0.2 mol / L malic acid solution, mix them evenly, react for 24 hours, wash with ultrapure water and dry to obtain modified phosphogypsum.

[0036] 2) Take 9kg of straw powder, 1kg of cow dung, 100g of kaolin, and 100g of microbial agent and mix them evenly to obtain a primary mixed material. Then take 5kg of modified phosphogypsum and 500g of the primary mixed material and mix them evenly. The water content of the mixture is controlled at about 60%. Then transfer it to an anaerobic bottle, and control the gaseous oxygen content in the fermentation bottle to 20Vol%. Ferment for 8 days; then introduce nitrogen into the anaerobic bottle, and control the gaseous oxygen content in the fermentation bottle to below 5Vol%. Ferment for 4 days to obtain fermented phosphogypsum rich in organic matter. Ferment once alternately.

[0037] 3) Add 1% by weight of magnesium sulfate and zinc sulfate composite conditioning materials to the fermented phosphogypsum, mix them evenly, and obtain regenerated soil.

[0038] The soil bulk density of the regenerated soil is 1.25 g / cm 3, pH value is 6, conductivity is 2.1mS / cm, organic matter content is 25g / kg, available phosphorus content is 620mg / kg, available potassium content is 2750mg / kg, alkaline nitrogen content is 280mg / kg, available calcium content is 375mg / kg, available magnesium content is 33 mg / kg, and available sulfur content is 14 mg / kg. According to the nutrient classification standard of the second national soil census, the nutrients of the regenerated soil belong to Class I. In addition, the contents of heavy metals such as Hg, Cd, As, Pb, Cr, Cu, and Ni in the regenerated soil are all lower than the screening values ​​of the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)" (GB15618-2018), which meets the agricultural standards.

[0039] Example 3 A method for preparing regenerated soil using phosphogypsum comprises the following steps: 1) Take 5 kg of phosphogypsum and 5 L of 0.1 mol / L tartaric acid solution, mix them evenly, react for 6 hours, wash with ultrapure water and dry to obtain modified phosphogypsum.

[0040] 2) Take 9kg of straw powder, 500g of pig manure, 100g of vermiculite, and 100g of microbial agent and mix them evenly to obtain a primary mixed material, then take 5kg of modified phosphogypsum and 1500g of the primary mixed material and mix them evenly. The water content of the mixed material is controlled at about 60%. Then transfer it to an anaerobic bottle, control the gaseous oxygen content in the fermentation bottle at 20Vol%, and ferment for 4 days; then introduce nitrogen into the anaerobic bottle, control the gaseous oxygen content in the fermentation bottle at less than 5Vol%, ferment for 3 days, and then alternately ferment once to obtain fermented phosphogypsum rich in organic matter.

[0041] 3) Add 1% by weight of magnesium sulfate and zinc sulfate composite conditioning materials to the fermented phosphogypsum, mix them evenly, and obtain regenerated soil.

[0042] The soil bulk density of the regenerated soil is 1.15 g / cm 3 , pH value is 6.8, conductivity is 2.42mS, cm, organic matter content is 51g / kg, available phosphorus content is 400mg / kg, available potassium content is 2150mg / kg, alkaline nitrogen content is 310mg / kg, available calcium content is 357mg / kg, available magnesium content is 32 mg / kg, and available sulfur content is 12 mg / kg. According to the nutrient classification standard of the second national soil census, the nutrients of the regenerated soil belong to Class I. In addition, the contents of heavy metals such as Hg, Cd, As, Pb, Cr, Cu, and Ni in the regenerated soil are all lower than the screening values ​​of the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)" (GB15618-2018), which meets the agricultural standards.

[0043] Example 4 A method for preparing regenerated soil using phosphogypsum comprises the following steps: 1) Take 5 kg of phosphogypsum and 10 L of 1 mol / L oxalic acid solution, mix them evenly, react for 12 h, wash with ultrapure water and dry to obtain modified phosphogypsum.

[0044] 2) Take 9kg of straw powder, 200g of bentonite, and 150g of microbial agent and mix them evenly to obtain a primary mixed material. Then take 5kg of modified phosphogypsum and 1kg of the primary mixed material and mix them evenly. The water content of the mixed material is controlled at about 60%. Then transfer it to an anaerobic bottle, and control the gaseous oxygen content in the fermentation bottle to 20Vol%. Ferment for 10 days; then introduce nitrogen into the anaerobic bottle, and control the gaseous oxygen content in the fermentation bottle to below 5Vol%. Ferment for 4 days to obtain fermented phosphogypsum rich in organic matter. Ferment only once.

[0045] 3) Add 1% by weight of magnesium sulfate and zinc sulfate composite conditioning materials to the fermented phosphogypsum, mix them evenly, and obtain regenerated soil.

[0046] The soil bulk density of the regenerated soil is 1.26 g / cm 3 , pH value is 6.3, conductivity is 2.28mS / cm, organic matter content is 45g / kg, available phosphorus content is 560mg / kg, available potassium content is 2650mg / kg, alkaline nitrogen content is 260mg / kg, available calcium content is 378mg / kg, available magnesium content is 30mg / kg, and available sulfur content is 15 mg / kg. According to the nutrient classification standard of the second national soil census, the nutrients of the regenerated soil belong to Class I. In addition, the contents of heavy metals such as Hg, Cd, As, Pb, Cr, Cu, and Ni in the regenerated soil are all lower than the screening values ​​of the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)" (GB15618-2018), which meets the agricultural land standards.

[0047] Example 5 A method for preparing regenerated soil using phosphogypsum comprises the following steps: 1) Take 5 kg of phosphogypsum and 10 L of 0.2 mol / L tartaric acid solution, mix them evenly, react for 12 h, wash with ultrapure water and dry to obtain modified phosphogypsum.

[0048] 2) Take 9kg of straw powder, 1kg of cow dung, 200g of bentonite, and 150g of composite bacterial agent and mix them evenly to obtain a primary mixed material. Then take 5kg of modified phosphogypsum and 1kg of the primary mixed material and mix them evenly. The water content of the mixed material is controlled at about 60%. Then transfer it to an anaerobic bottle, control the gaseous oxygen content in the fermentation bottle at 20Vol%, ferment for 15 days, and then introduce nitrogen into the anaerobic bottle, control the gaseous oxygen content in the fermentation bottle at less than 5Vol%, ferment for 8 days, and obtain fermented phosphogypsum rich in organic matter. Ferment once alternately.

[0049] 3) Add 0.5% by weight of magnesium sulfate and zinc sulfate composite conditioning materials to the fermented phosphogypsum, mix them evenly, and obtain regenerated soil.

[0050] The soil bulk density of the regenerated soil is 1.24 g / cm 3 , pH value is 6.8, conductivity is 2.42mS / cm, organic matter content is 47g / kg, available phosphorus content is 572mg / kg, available potassium content is 2750mg / kg, alkaline nitrogen content is 310mg / kg, available calcium content is 368mg / kg, available magnesium content is 29 mg / kg, and available sulfur content is 13 mg / kg. According to the nutrient classification standard of the second national soil census, the nutrients of the regenerated soil belong to Class I. In addition, the contents of heavy metals such as Hg, Cd, As, Pb, Cr, Cu, and Ni in the regenerated soil are all lower than the screening values ​​of the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial) (GB15618-2018)", which meets the agricultural land standards.

[0051] Example 6 A method for preparing regenerated soil using phosphogypsum comprises the following steps: 1) Take 5 kg of phosphogypsum and 10 L of 0.1 mol / L tartaric acid solution and mix them evenly, microwave ultrasound for 20 min, wash with ultrapure water and dry to obtain modified phosphogypsum.

[0052] 2) Take 9kg of straw powder, 1kg of cow dung, 500g of attapulgite, and 150g of composite bacterial agent and mix them evenly to obtain a primary mixed material. Then take 5kg of modified phosphogypsum and 1kg of the primary mixed material and mix them evenly. The water content of the mixed material is controlled at about 60%. Then transfer it to an anaerobic bottle, control the gaseous nitrogen content in the fermentation bottle at 20Vol%, and ferment for 6 days; then introduce nitrogen into the anaerobic bottle, control the gaseous oxygen content in the fermentation bottle at less than 5Vol%, ferment for 3 days, and then alternately ferment once to obtain fermented phosphogypsum rich in organic matter.

[0053] 3) Adding 1% of olivine mineral conditioning material by weight to the fermented phosphogypsum to obtain regenerated soil.

[0054] The soil bulk density of the regenerated soil is 1.29 g / cm 3 , pH value is 6.5, conductivity is 2.36mS / cm, organic matter content is 42g / kg, available phosphorus content is 550mg / kg, available potassium content is 2632mg / kg, alkaline nitrogen content is 295mg / kg, available calcium content is 370mg / kg, available magnesium content is 25 mg / kg, and available sulfur content is 15 mg / kg. According to the nutrient classification standard of the second national soil census, the nutrients of the regenerated soil belong to Class I. In addition, the contents of heavy metals such as Hg, Cd, As, Pb, Cr, Cu, and Ni in the regenerated soil are all lower than the screening values ​​of the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)" (GB15618-2018), which meets the agricultural land standards.

[0055] Comparative Example 1 This comparative example uses phosphogypsum as soil, which is directly used for crop planting without organic acid treatment and aerobic-anaerobic alternating fermentation treatment. The pH value of the sample is 3.3, the conductivity is 4.656Ms / cm, the organic matter content is 1.69g / kg, the available phosphorus is 1779g / kg, the available calcium content is 130mg / kg, the available magnesium content is 8 mg / kg, and the available sulfur content is 7mg / kg. According to the nutrient classification standard of the second national soil survey, the soil organic matter nutrient belongs to the fourth level (middle and lower) quality.

[0056] Application Examples The regenerated soil prepared in Example 1, Example 2 and Comparative Example 1 was placed in a flower pot with an upper diameter of 25 cm and a height of 20 cm to plant royal grass. During the planting process, water was poured once every 3 days to replenish the soil moisture to 80% of the field drainage volume of the soil. During the planting period, the parameters such as plant height, diameter, and tillering of the royal grass were recorded. The test results are as follows: Comparison table of the characteristics of king grass planted in regenerative soil under different conditions It can be seen from the data in the table that the regenerated soil obtained from phosphogypsum after organic acid treatment and aerobic-anaerobic alternating fermentation treatment is more conducive to the growth of king grass.

[0057] In summary, the present invention provides a method and application for preparing regenerated soil using phosphogypsum, which belongs to the field of solid waste resource utilization. The method is: modifying the phosphogypsum by an organic acid solution to remove impurity elements in the phosphogypsum to meet land utilization requirements. Then, the modified phosphogypsum is subjected to microbial aerobic-anaerobic alternating fermentation to promote the dissolution of phosphogypsum and the formation of humus, thereby improving the bioavailability and durability of nutrients in the phosphogypsum-based regenerated soil. Finally, the fermented phosphogypsum is stirred and mixed with trace element additives to form plantable soil.

[0058] The present invention uses bulk solid waste phosphogypsum as raw material, makes full use of elements such as Ca, S, and P in phosphogypsum, and obtains regenerated soil with high fertility, stable structure, and strong water and fertilizer retention capacity through harmless treatment (organic acid washing), alternating fermentation of aerobic and anaerobic microorganisms, and compounding of trace element additives. This method can not only effectively solve the problem of phosphogypsum storage, but also can apply the obtained regenerated soil to farmland improvement, land reclamation, and crop planting, achieving the goal of turning waste into treasure.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing regenerated soil using phosphogypsum, characterized in that: The method comprises the following steps: Step S1: fully and evenly mix phosphogypsum and an organic acid solution with a molar concentration of 0.1-1 mol / L, react for 1-24 hours, wash with water and dry to obtain modified phosphogypsum; Step S2: uniformly mixing the modified phosphogypsum, clay mineral, microbial agent and organic matter in step S1 according to a certain proportion by a step-by-step mixing method, and then transferring them into a fermentation device, and performing aerobic-anaerobic alternating microbial fermentation by changing the atmosphere in the fermentation device to obtain fermented phosphogypsum rich in organic matter; Step S3: adding a trace element compounding agent to the fermented phosphogypsum in step S2, and mixing them evenly to obtain regenerated soil.

2. The method according to claim 1, characterized in that The organic acid solution in step S1 is one or more of oxalic acid, ethylenediaminetetraacetic acid, citric acid, formic acid, acetic acid, propionic acid, lactic acid, succinic acid, malonic acid, maleic acid, tartaric acid, succinic acid, malic acid, benzoic acid, phenylacetic acid, phthalic acid, terephthalic acid, valeric acid, caproic acid, capric acid, stearic acid, and acrylic acid.

3. The method according to claim 1, characterized in that The clay mineral in step S2 is one or more of montmorillonite, kaolinite, halloysite, palygorskite, sepiolite, illite, talc, sericite, and vermiculite; the microbial agent is a mixture of yeast agents, line-proofing agents, lactic acid bacteria agents, sulfate-reducing bacteria agents, phosphate-solubilizing bacteria, nitrogen-fixing bacteria, and potassium-solubilizing bacteria; and the organic matter is one or more of livestock and poultry manure, livestock and poultry carcasses, kitchen waste, biogas residue, mushroom residue, urban sludge, and crop straw.

4. The method according to claim 1, characterized in that The step-by-step mixing method in step S2 is to firstly mix the organic matter, clay mineral and microbial agent in a mass ratio of 1:0.01-0.2:0.01-0.1 to obtain a primary mixed material, and then uniformly mix the modified phosphogypsum and the primary mixed material in a mass ratio of 1:0.1-0.6, and control the water content of the mixed material to be 60%.

5. The method according to claim 1, characterized in that The aerobic-anaerobic alternating microbial fermentation in step S2 is to perform aerobic fermentation on the mixed material and then perform anaerobic fermentation, and the alternation is repeated 1-10 times.

6. The method according to claim 5, characterized in that Aerobic fermentation is microbial fermentation under air atmosphere, the gaseous oxygen content in the fermentation device is controlled at 5-21Vol%, and the fermentation time is 4-20 days; anaerobic fermentation is to pass nitrogen atmosphere into the fermentation bottle, control the gaseous oxygen content in the fermentation device to be less than 5Vol%, and the fermentation time is 3-15 days.

7. The method according to claim 1, characterized in that The trace element compounding agent in step S3 is a natural mineral conditioning material or an inorganic reagent, and the added amount of the trace element compounding agent accounts for less than 10% of the total mass.

8. The method according to claim 7, characterized in that The natural mineral conditioning material is one or more of feldspar, mica, amphibole, pyroxene, olivine, garnet, dolomite, allophane, and iron oxide; the inorganic reagent is one or more of ammonium sulfate, zinc sulfate, magnesium sulfate, borax, and calcium nitrate.

9. A regenerated soil prepared using phosphogypsum, characterized in that: The regenerated soil is prepared by the method for preparing regenerated soil using phosphogypsum as described in any one of claims 1 to 8.

10. The regenerated soil as claimed in claim 9 is used in the field of crop planting.

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