A microbial load type silicon-calcium-potassium-magnesium phosphate soil conditioner based on double tailings synergistic activation and a preparation method thereof

Abstract

The application provides a microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailing ore cooperative activation and a preparation method thereof, and relates to the field of solid waste recycling. The soil conditioner comprises a porous carrier and a protective layer, an adsorption layer, a bacterial agent layer and a fixed layer arranged on the surface of the porous carrier in sequence. The raw materials of the porous carrier comprise phosphorus tailing, silicate type tailing, pore forming agent and binder solution. The raw materials of the protective layer comprise first coating liquid and first cross-linking liquid, and the first coating liquid comprises an aqueous solution composed of sodium alginate, chitosan, glycerol and sodium dihydrogen phosphate. The raw materials of the adsorption layer comprise second coating liquid, and specifically comprise an aqueous solution composed of chitosan, humic acid and acetic acid. The raw materials of the bacterial agent layer comprise bacterial agent, pH buffer, cell protective agent, nutrient activator and water. The raw materials of the fixed layer comprise third coating liquid and second cross-linking liquid. The soil conditioner has the effects of providing valuable components, inhibiting the growth of pathogens, promoting plant growth and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solid waste recycling, and in particular to a microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings collaborative activation and a preparation method thereof. BACKGROUND

[0002] Tailings are a large amount of solid waste produced in the mineral processing process, and silicate tailings refer to tailings with silicate minerals as the main component, including part of non-metallic mineral tailings (such as quartz sand tailings, feldspar tailings, kaolin tailings, etc.) and metal mine tailings (such as iron tailings, copper tailings, gold tailings, lead-zinc tailings, molybdenum-tungsten tailings, etc.), and phosphorus tailings are tailings produced in the mineral processing of phosphate rock, and the main component is carbonate mineral. The comprehensive utilization rate of silicate tailings and phosphorus tailings in China is only 30%, and the existing comprehensive utilization direction is mainly low-value direction such as underground filling, building materials, road materials, etc., and the product has limited functionality and lacks market prospects.

[0003] Tailings preparation of soil conditioner is one of the new directions of high-value utilization of tailings. The existing tailings roasting method and hydrothermal method for preparing soil conditioner can convert the inert state of valuable elements in tailings into plant absorbable effective state, but a large amount of activators such as CaCO3, Na2CO3, NaOH, etc. are needed, which increases the cost and greatly reduces the utilization rate of tailings, and the mixing amount is only about 50%. In addition, due to the limitation of the existing activation process (activation efficiency 50%-80%), part of the valuable elements in the tailings-based soil conditioner is still in the ineffective state and cannot be absorbed and utilized by plants.

[0004] On the other hand, the role of tailings-based soil conditioner is mainly limited to supplementing soil with mineral elements such as silicon, calcium, potassium, magnesium, and phosphorus and improving the pH value of acidic soil, and it is difficult to meet the comprehensive needs of soil physical structure improvement, promotion of organic matter transformation, inhibition of pathogens or biological activity regulation, etc. It cannot meet the multi-modification goals in complex soil environment. At the same time, due to the limitation of preparation process and its own properties, the tailings-based soil conditioner has strong alkalinity, and it is impossible to improve the conditioning effect and expand the product function by simply compounding microbial agents.

[0005] Therefore, the present application provides a microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings collaborative activation and a preparation method thereof to solve the above problems. SUMMARY

[0006] The purpose of the present application is to provide a microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings collaborative activation and a preparation method thereof to solve the above problems.

[0007] To achieve the above object, the first aspect of the present application provides a microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation, comprising a porous carrier and a protective layer, an adsorption layer, a bacterial agent layer and a fixed layer arranged on the surface of the porous carrier in sequence;

[0008] The raw material of the porous carrier comprises phosphorus tailings, silicate type tailings, pore forming agent and binder solution; the pore forming agent comprises citric acid and straw powder, and the binder solution comprises an aqueous solution of one or more of polyvinyl alcohol, starch and humic acid;

[0009] The raw material of the protective layer comprises a first coating liquid and a first cross-linking liquid, and the first coating liquid comprises an aqueous solution of sodium alginate, chitosan, glycerol and sodium dihydrogen phosphate;

[0010] The raw material of the adsorption layer comprises a second coating liquid, and the second coating liquid comprises an aqueous solution of chitosan, humic acid and acetic acid;

[0011] The raw material of the bacterial agent layer comprises a bacterial liquid, and the bacterial liquid comprises a bacterial agent, a pH buffer, a cell protective agent, a nutrient activator and water;

[0012] The raw material of the fixed layer comprises a third coating liquid and a second cross-linking liquid, and the third coating liquid is an aqueous solution of sodium alginate;

[0013] The first cross-linking liquid and the second cross-linking liquid comprise an aqueous solution of calcium chloride.

[0014] Optionally, the microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation satisfies at least one of the following conditions:

[0015] A. The mass content of dolomite in the phosphorus tailings is ≥50%, and the mass content of hydroxyapatite is ≥10%;

[0016] B. The mass content of SiO2 in the silicate type tailings is ≥40%, and the mass content of K2O is ≥5%;

[0017] C. The raw material of the pore forming agent comprises, by mass fraction:

[0018] Citric acid 30-50 parts, straw powder 50-70 parts.

[0019] D. The raw material of the porous carrier comprises, by mass fraction:

[0020] Phosphorus tailings 50-70 parts, silicate type tailings 30-50 parts, pore forming agent 8-15 parts, and binder solution 10-20 parts;

[0021] E. The effective state SiO2 mass content is ≥25%, the effective state CaO mass content is ≥20%, the effective state MgO mass content is ≥8%, the effective state P2O5 mass content is ≥5%, the effective state K2O mass content is ≥2%, the effective active bacteria number is ≥1×10 8 CFU / g, and the survival rate of the microbial agent is ≥85% within 30 days.

[0022] Optionally, the microbial agent based on double tailings synergistic activation of silicon calcium potassium magnesium phosphorus soil conditioner meets at least one of the following conditions:

[0023] A. In the first coating liquid, the mass concentration of sodium alginate is 1.0%-2.0%, the mass concentration of chitosan is 0.5%-1.0%, the mass concentration of glycerol is 0.5%-1.0%, and the mass concentration of sodium dihydrogen phosphate is 0.5%-1.0%;

[0024] B. In the second coating liquid, the mass concentration of chitosan is 2.0%-3.0%, the mass concentration of humic acid is 0.5%-1.0%, and the mass concentration of acetic acid is 0.5-2.0%;

[0025] C. In the raw material of the fixed layer, the mass concentration of sodium alginate solution is 1.0%-2.0%.

[0026] D. In the first cross-linking liquid and the second cross-linking liquid, the mass concentration of calcium chloride is 2.0%-5.0%.

[0027] Optionally, the microbial agent based on double tailings synergistic activation of silicon calcium potassium magnesium phosphorus soil conditioner meets at least one of the following conditions:

[0028] A. The bacterial solution includes, by mass fraction:

[0029] The bacterial agent is 55-70 parts, the pH buffer is 10-20 parts, the cell protection agent is 10-15 parts, the nutrient activator is 5-10 parts, and the water is 200-300 parts;

[0030] B. The pH value of the bacterial solution is 6.5-7.5.

[0031] Optionally, the microbial agent based on double tailings synergistic activation of silicon calcium potassium magnesium phosphorus soil conditioner meets at least one of the following conditions:

[0032] A. the bacterial agent comprises, by mass fraction: Bacillus subtilis 25-30 parts, Bacillus mycoides 25-30 parts, Bacillus licheniformis 20-25 parts, Bacillus megaterium 10-15 parts, Brevibacillus laterosporus 5-10 parts;

[0033] B. the number of effective viable bacteria in the bacterial agent is greater than 5×10 9 CFU / g;

[0034] C. the pH buffer comprises, by mass fraction: sodium dihydrogen phosphate 40-50 parts, disodium hydrogen phosphate 50-60 parts;

[0035] D. the cell protective agent comprises, by mass fraction: trehalose 50-70 parts, polyvinylpyrrolidone 20-30 parts, skimmed milk powder 15-30 parts, sodium ascorbate 3-5 parts;

[0036] E. the nutritional activator comprises, by mass fraction: glucose 60-70 parts, yeast extract powder 30-40 parts, magnesium sulfate 3-5 parts.

[0037] Optionally, the microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation meets at least one of the following conditions:

[0038] A. the thickness of the protective layer is 30-50 μm;

[0039] B. the thickness of the adsorption layer is 50-70 μm;

[0040] C. the thickness of the fixed layer is 15-30 μm.

[0041] The second aspect of the present application provides a preparation method of the microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation, comprising:

[0042] S1: first mixing phosphorus tailings, silicate type tailings and pore forming agent to obtain a first mixture, and granulating, first drying, calcining and cooling the first mixture by adding a binder solution to obtain a porous carrier;

[0043] S2: second mixing the porous carrier and a first coating liquid to obtain a first coated carrier, and third mixing the first coated carrier and a first cross-linking liquid, and second drying to obtain a protective layer coated carrier;

[0044] S3: fourth mixing the protective layer coated carrier and a second coating liquid, and third drying to obtain an adsorption layer coated carrier;

[0045] S4: setting a bacterial liquid on the surface of the adsorption layer coated carrier, and fourth drying to obtain a bacterial agent layer coated carrier;

[0046] S5: the coating layer of the microbial agent is coated with the third coating solution to obtain a third coated carrier, and the third coated carrier is mixed with a second cross-linking solution to obtain a microbial-loaded silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation through sixth mixing and fifth drying.

[0047] Optionally, the preparation method of the microbial-loaded silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation satisfies at least one of the following conditions:

[0048] A. The particle size of the phosphorus tailings, the silicate tailings, and the pore-forming agent is independently less than or equal to 0.074 mm;

[0049] B. The mass concentration of the binder solution is 3.0%-8.0%;

[0050] C. The rotating speed of the granulating disc is 30-40 r / min, and the granulating time is 3-5 min;

[0051] D. The particle size of the granulated material is 2 mm-3 mm.

[0052] Optionally, the calcination includes first calcination and second calcination performed in sequence;

[0053] The temperature of the first calcination is 800-950°C, and the holding time is 30-120 min;

[0054] The temperature of the second calcination is 1100-1200°C, and the holding time is 30-60 min.

[0055] Optionally, the preparation method of the microbial-loaded silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation satisfies at least one of the following conditions:

[0056] A. The mass ratio of the porous carrier to the first coating solution is 1:5-8, and the mass ratio of the porous carrier to the first cross-linking solution is 1:5-8;

[0057] B. The mass ratio of the porous carrier to the second coating solution is 1:5-8;

[0058] C. The mass ratio of the porous carrier to the microbial solution is 3-5:1;

[0059] D. The mass ratio of the porous carrier to the third coating solution is 1:5-8, and the mass ratio of the porous carrier to the second cross-linking solution is 1:5-8;

[0060] E. The time of the second mixing, the third mixing, the fourth mixing, and the fifth mixing is independently 5-10 min;

[0061] F. The temperature of the first drying, the second drying, the third drying, the fourth drying and the fifth drying is independently 40-50℃, and the time is independently 10-30min.

[0062] Compared with the prior art, the beneficial effects of the present application include:

[0063] The microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation provided by the present application makes full use of the porous structure generated by the calcination decomposition of dolomite in phosphorus tailings and the decomposition of pore-forming agents, and has the advantages of mineral source soil conditioner and microbial soil conditioner through the structure of inorganic mineral source carrier carrying microbial agents. On the basis of providing silicon-calcium-potassium-magnesium-phosphorus valuable components, adjusting pH, and fixing heavy metals in conventional tailings-based soil conditioners, the product also has the effects of promoting soil organic matter transformation and inhibiting the growth and reproduction of pathogens, etc. In addition, silicate bacteria and phosphorus solubilizing bacteria in the microbial agent can further decompose residual unactivated minerals in the tailings in the soil environment, improving the conversion rate and utilization rate of silicon-calcium-potassium-magnesium-phosphorus elements. The product can be widely used in agricultural production, soil remediation, landscaping, urban greening and other fields.

[0064] The preparation method of the microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation provided by the present application utilizes the component compatibility relationship of phosphorus tailings and silicate type tailings. Under high temperature conditions, dolomite and hydroxyapatite in phosphorus tailings react with silicate minerals such as quartz and potassium feldspar in silicate type tailings. Without adding any activator, efficient and synchronous activation of silicon, calcium, potassium, magnesium and phosphorus can be achieved, which improves the utilization rate of tailings while reducing the technical cost. In addition, the preparation method of the functional coating layer and the coating structure of the fixation layer-adsorption layer-protection layer solve the problem that the tailings-based soil conditioner is too alkaline and the microbial agent cannot survive, and enrich the functionality of the soil conditioner. BRIEF DESCRIPTION OF DRAWINGS

[0065] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope of the present application.

[0066] Figure 1 The preparation method of the microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation provided by the present application is shown in the flowchart. DETAILED DESCRIPTION

[0067] As used herein:

[0068] "Produced from" is synonymous with "comprising." As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0069] When expressing a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values for an equivalent, concentration, or other value or parameter, it is to be understood that all ranges formed by any pairings of an upper or preferred value from any range with a lower or preferred value from any range are specifically disclosed, whether the range is expressly disclosed or not. For example, when a range "1-5" is disclosed, the described range should be interpreted to include ranges "1-4," "1-3," "1-2," "1-2 and 4-5," "1-3 and 5," etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include the end values and all integers and fractions within that range.

[0070] In these examples, unless otherwise indicated, the parts and percentages are by mass.

[0071] "Mass parts" refers to a basic unit of measurement that represents the proportional relationship of the mass of multiple components, 1 part can represent any unit mass, such as 1 g, 2.689 g, etc. If we say that the mass parts of component A is a parts, and the mass parts of component B is b parts, it means that the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK, and the mass of component B is bK (K is an arbitrary number, representing a multiple factor). It must not be misunderstood that, unlike mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0072] "And / or" is used to indicate that one or both of the stated conditions can occur, for example, A and / or B includes (A and B) and (A or B).

[0073] On the one hand, the existing tailings preparation soil conditioner technology often needs to add a large amount of alkaline additives, such as calcium carbonate, sodium carbonate, dolomite and sodium hydroxide, in the process of realizing the activation of valuable elements, resulting in low utilization rate of tailings (about 50% of tailings content), high cost and poor technical and economic performance; In addition, due to the limitation of the existing activation process (activation efficiency 50%-80%), part of the valuable elements in the tailings-based soil conditioner is still in the ineffective state and cannot be absorbed and utilized by plants.

[0074] On the other hand, the existing tailings-based soil conditioner has a single function, and it is difficult to achieve multiple improvement goals in complex soil environments. Compounding microbial inoculants is an effective method to improve the functionality of soil conditioners, but the strong alkalinity of tailings-based soil conditioners is not conducive to the survival of microorganisms, and the improvement of conditioning effect and the expansion of product function cannot be achieved by simply compounding microbial inoculants.

[0075] Based on this, the first aspect of the present application provides a microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation, comprising a porous carrier and a protective layer, an adsorption layer, a microbial inoculant layer and a fixed layer arranged on the surface of the porous carrier in sequence;

[0076] The raw material of the porous carrier includes phosphorus tailings, silicate type tailings, pore forming agent and binder solution; the pore forming agent includes citric acid and straw powder, and the binder solution includes an aqueous solution of one or more of polyvinyl alcohol, starch and humic acid;

[0077] It should be noted that the pore forming agent contains citric acid and straw powder, wherein citric acid decomposes to produce CO2 and H2O gas at 200-400℃, forming microporous structures inside the carrier, and citric acid and its intermediate products in the decomposition process can chelate calcium ions in hydroxyapatite, thereby destroying the crystal structure of hydroxyapatite and promoting the conversion of insoluble phosphorus into effective phosphorus that can be absorbed by plants; during high-temperature sintering, cellulose and hemicellulose in straw powder are carbonized to form macroporous channels, while lignin residues form mesoporous structures, which can effectively improve the porosity. In addition, the ash of straw is rich in potassium and other elements, and reacts with SiO2 in silicate type tailings above 900℃ to form potassium silicate, thereby increasing the content of effective potassium in the carrier;

[0078] The raw material of the protective layer includes a first coating liquid and a first cross-linking liquid, and the first coating liquid includes an aqueous solution of sodium alginate, chitosan, glycerol and sodium dihydrogen phosphate;

[0079] It should be noted that the protective layer is the bottom layer, and its main function is to prevent direct contact between the alkaline carrier and the microbial inoculant by building a physical barrier to improve the survival rate of the microbial inoculant;

[0080] The raw material of the adsorption layer includes a second coating liquid, and the second coating liquid includes an aqueous solution of chitosan, humic acid and acetic acid;

[0081] It should be noted that the adsorption layer is the outer layer, and its main function is to strengthen the bonding strength between the microbial inoculant and the surface of the carrier, thereby improving the loading rate of the microbial inoculant and providing an initial environment for the microbial inoculant to adhere, grow and metabolize;

[0082] The raw material of the microbial inoculant layer includes a bacterial solution, and the bacterial solution includes a microbial inoculant, a pH buffer, a cell protectant, a nutrient activator and water;

[0083] The raw material of the fixed layer includes a third coating liquid and a second cross-linking liquid, the third coating liquid is a sodium alginate aqueous solution, and the first cross-linking liquid and the second cross-linking liquid include a calcium chloride aqueous solution.

[0084] It should be noted that the sodium alginate-calcium chloride coating of the fixed layer seals the internal bacterial agent during storage and transportation, prevents water loss and physical abrasion, and slowly dissolves through ion exchange after being applied to the soil, thereby achieving targeted slow release of microorganisms and effectively prolonging the action period of the bacterial agent. In some embodiments, the microbial load-type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double-tailings synergistic activation meets at least one of the following conditions:

[0085] A. The mass content of dolomite in the phosphorus tailings is ≥50%, and the mass content of hydroxyapatite is ≥10%;

[0086] Optionally, the content of dolomite in the phosphorus tailings can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, or any value ≥50%, and the mass content of hydroxyapatite can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, or any value ≥10%;

[0087] It should be noted that dolomite in the phosphorus tailings can provide effective calcium and magnesium, and generate gas during calcination and thermal decomposition, resulting in pores on the surface of the particles. It can also react with silicate-type tailings under high temperature conditions, converting inert silicon into effective silicon; hydroxyapatite can provide effective phosphorus and reduce the melting point of the system, promoting the activation of silicon, and the generated phosphate can solidify heavy metals during calcination and thermal decomposition;

[0088] B. The mass content of SiO2 in the silicate-type tailings is ≥40%, and the mass content of K2O is ≥5%;

[0089] Optionally, the mass content of SiO2 in the silicate-type tailings can be 40%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or any value ≥40%, and the mass content of K2O can be 5%, 6%, 8%, 10%, 15%, or any value ≥5%.

[0090] C. The raw material of the pore-forming agent includes, by mass fraction:

[0091] Citric acid 30-50 parts, straw powder 50-70 parts.

[0092] Optionally, the raw material of the pore-forming agent, by mass fraction, citric acid can be 30 parts, 33 parts, 35 parts, 40 parts, 50 parts, or any value between 30-50 parts, and straw powder can be 50 parts, 51 parts, 53 parts, 55 parts, 60 parts, or any value between 50-70 parts.

[0093] D. The raw materials of the porous carrier include, by mass fraction:

[0094] Phosphorus tailings 50-70 parts, silicate type tailings 30-50 parts, pore forming agent 8-15 parts, binder solution 10-20 parts;

[0095] Optionally, the raw materials of the porous carrier include, by mass fraction, phosphorus tailings 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, or any value between 50-70 parts; silicate type tailings 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, or any value between 30-50 parts; pore forming agent 8 parts, 9 parts, 10 parts, 11 parts, or any value between 8-15 parts; binder solution 10 parts, 11 parts, 12 parts, 15 parts, or any value between 10-20 parts.

[0096] E. In the microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation, the mass content of effective state SiO2 is ≥25%, the mass content of effective state CaO is ≥20%, the mass content of effective state MgO is ≥8%, the mass content of effective state P2O5 is ≥5%, the mass content of effective state K2O is ≥2%, and the number of effective live bacteria is ≥1×10 8 CFU / g, and the survival rate of the microbial agent within 30 days is ≥85%.

[0097] Optionally, in the microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation, the mass content of effective state SiO2 can be 25%, 30%, 35%, 40%, or any value ≥25%, the mass content of effective state CaO can be 20%, 25%, 30%, 35%, 40%, or any value ≥20%, the mass content of effective state MgO can be 8%, 10%, 12%, 14%, 16%, 18%, 20%, 30%, or any value ≥8%, the mass content of effective state P2O5 can be 5%, 6%, 7%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, or any value ≥5%, the mass content of effective state K2O can be 2%, 3%, 4%, 5%, 8%, 10%, or any value ≥2%, and the number of effective live bacteria can be 1×10 8 CFU / g, 2×10 8 CFU / g, 5×10 8 CFU / g, 1×10 9 CFU / g, 5×10 9 CFU / g, 1×10 10 CFU / g, or ≥1×10 8 CFU / g, or any value ≥1×10 CFU / g, and the survival rate of the microbial agent within 30 days can be 85%, 86%, 88%, 90%, 95%, or any value ≥85%.

[0098] In some embodiments, the double-tailings synergistically activated microbial load type silicon calcium potassium magnesium soil conditioner meets at least one of the following conditions:

[0099] A. In the first coating liquid, the mass concentration of sodium alginate is 1.0%-2.0%, the mass concentration of chitosan is 0.5%-1.0%, the mass concentration of glycerol is 0.5%-1.0%, and the mass concentration of sodium dihydrogen phosphate is 0.5%-1.0%;

[0100] Optionally, in the first coating liquid, the mass concentration of sodium alginate can be 1.0%, 1.5%, 2.0% or any value between 1.0% and 2.0%, the mass concentration of chitosan can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0% or any value between 0.5% and 1.0%, the mass concentration of glycerol can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0% or any value between 0.5% and 1.0%, and the mass concentration of sodium dihydrogen phosphate can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0% or any value between 0.5% and 1.0%;

[0101] It should be noted that the protective layer is to form a barrier layer between the alkaline carrier and buffer alkaline, moisturizing and preventing cracking; wherein sodium alginate as the main film-forming material and crosslinking agent calcium chloride ion crosslinking reaction, crosslinking after the formation of calcium alginate gel network, effectively block the invasion of external alkaline substances and internal bacteria loss. The positively charged amino groups in the chitosan molecule and the carboxyl groups in the protective layer matrix sodium alginate form a polyelectrolyte complex through electrostatic interaction, which regulates the film-forming property, and can also produce strong electrostatic attraction and hydrogen bond with the negatively charged substances such as humic acid in the adsorption layer, promoting the combination of the protective layer and the adsorption layer. Glycerol as a plasticizing and moisturizing agent, inserted between the polymer chains of calcium alginate, effectively prevents the calcium alginate film from becoming brittle and cracking during the drying process, and maintains its flexibility and integrity; sodium dihydrogen phosphate as a pH buffer, forms a phosphate buffer system in the microenvironment of the protective layer, which can continuously neutralize the small amount of OH - counteract the fatal effects of high alkalinity of the carrier.

[0102] In addition, the coating liquid concentration cannot be too high, which can easily lead to over-thickening of the film and blockage of the pores; and if the coating liquid concentration is too low, it can lead to discontinuous film formation, defects or over-thinning, which cannot effectively block alkaline substances and has insufficient mechanical strength, and is prone to cracking during drying or subsequent processing, losing the protective function.

[0103] It should be noted that the formula of the protective layer realizes precise defense for the high-alkaline carrier and effective combination with the adsorption layer, and the specific effects are as follows:

[0104] (1) Silicate tailings and phosphate tailings have extremely high surface activity after high-temperature roasting and grinding, and can continuously hydrolyze to release Ca 2+ , Mg 2+ and OH - ions, forming a persistent high-alkaline microenvironment. The first coating realizes a nano-scale physical barrier to the external calcium alginate film through the dense "egg box" gel structure of the film by the synergistic mechanism of "physical barrier" and "chemical neutralization", greatly slowing down the diffusion rate of OH - ; At the same time, the sodium dihydrogen phosphate embedded in the gel network forms a dynamic phosphate buffer system, which can continuously neutralize the OH⁻ permeating into the interior, stabilizing the internal microenvironment pH in the neutral range;

[0105] (2) Humic acid and other materials are usually rich in negative groups and have certain porosity and hydrophilicity. The positive amino groups (-NH3 + ) of chitosan in the protective layer can strongly bind sodium alginate inside the protective layer and negative groups in the external adsorption layer, forming a stable composite network between the protective layer and the adsorption layer through electrostatic interaction and hydrogen bonding;

[0106] B. In the second coating liquid, the mass concentration of chitosan is 2.0%-3.0%, the mass concentration of humic acid is 0.5%-1.0%, and the mass concentration of acetic acid is 0.5-2.0%;

[0107] Optionally, the mass concentration of chitosan can be 2.0%, 2.5%, 3.0%, or any value between 2.0% and 3.0%, the mass concentration of humic acid can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, or any value between 0.5% and 1.0%, and the mass concentration of acetic acid can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 2.0%, or any value between 0.5% and 2.0%;

[0108] It is to be noted that the adsorption layer provides a firm anchoring point for the microbial inoculant on the carrier surface and optimizes the initial survival microenvironment thereof; wherein, after the chitosan is protonated in the acetic acid solution, the linear molecular chain thereof is fully stretched, and a dense, continuous and extremely strong adhesion film can be formed on the carrier surface by flow casting. This film not only generates strong static anchoring with the negatively charged bacterial bodies and the carrier surface by virtue of the cationic characteristics thereof, but also serves as an ideal pre-coating matrix to form a firm adhesion interface with the protective layer, thereby significantly enhancing the integrity and stability of the multi-layer structure; the acetic acid not only protonates and fully stretches the chitosan molecular chain to exert the adsorption performance, but also generates micro-pores during the drying process to provide more sites for the adsorption of the inoculant; the humic acid, as a natural microenvironment regulator, has a quinone / phenol functional group in the molecule thereof, which constitutes a reversible redox pair to stabilize the electronic potential around the bacterial bodies to ensure the energy metabolism, and provides a mild pH buffering capacity by virtue of the complex functional groups thereof, in addition, the humic acid itself can provide nutrition for the inoculant as a slow-release organic carbon source, and comprehensively optimizes the micro-ecological environment of the adhesion point.

[0109] It is to be noted that the formula of the adsorption layer meets the inoculant colonization requirements and the deep combination with the protective layer, and the specific effects are as follows:

[0110] (1) The exposed amino groups of the chitosan in the adsorption layer are anchored to the negatively charged bacterial cell surface by strong electrostatic attraction after the chitosan is protonated by acetic acid, thereby realizing the rapid initial fixation of the inoculant on the carrier surface; the acetic acid volatilizes during the drying process to provide more sites for the adsorption of the inoculant, and the humic acid creates a good colonization environment for the inoculant;

[0111] (2) The carboxyl groups of the calcium alginate in the protective layer can further electrostatically complex with the protonated amino groups, thereby forming a firm ionic bond network to improve the combination strength of the adsorption layer and the protective layer and solve the problem of separation between the layers of the multi-layer coating;

[0112] C. In the raw materials of the fixing layer, the mass concentration of the sodium alginate aqueous solution is 1.0%-2.0%;

[0113] Optionally, in the raw materials of the fixing layer, the mass concentration of the sodium alginate aqueous solution can be 1.0%, 1.5%, 2.0% or any value between 1.0% and 2.0%;

[0114] D. In the first cross-linking liquid and the second cross-linking liquid, the mass concentration of the calcium chloride is independently 2.0%-5.0%.

[0115] Optionally, in the first cross-linking liquid and the second cross-linking liquid, the mass concentration of the calcium chloride can be 2.0%, 3.0%, 4.0%, 5.0% or any value between 2.0% and 5.0%.

[0116] In some embodiments, the microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation satisfies at least one of the following conditions:

[0117] A. The bacterial solution includes, by mass fraction:

[0118] The bacterial agent is 55-70 parts, the pH buffer is 10-20 parts, the cell protective agent is 10-15 parts, the nutrient activator is 5-10 parts, and the water is 200-300 parts;

[0119] Optionally, the bacterial solution includes, by mass fraction, the bacterial agent can be 55 parts, 60 parts, 65 parts, 70 parts, or any value between 55-70 parts, the pH buffer can be 10 parts, 15 parts, 20 parts, or any value between 10-20 parts, the cell protective agent can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, or any value between 10-15 parts, the nutrient activator can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, or any value between 5-10 parts, and the water can be 200 parts, 220 parts, 240 parts, 260 parts, 300 parts, or any value between 200-300 parts;

[0120] It should be noted that the bacterial agent is the core part of the bacterial solution, the pH buffer prevents the influence of pH changes on the activity of the bacterial agent, the cell protective agent improves the survival rate of the bacterial body under adverse conditions such as drying, cryopreservation, high temperature, and oxidation, and the nutrient activator improves the initial activity of the bacterial agent;

[0121] B. The pH value of the bacterial solution is 6.5-7.5.

[0122] Optionally, the pH value of the bacterial solution can be 6.5, 7.0, 7.5, or any value between 6.5-7.5.

[0123] In some embodiments, the microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation satisfies at least one of the following conditions:

[0124] A. The bacterial agent includes, by mass fraction: Bacillus subtilis 25-30 parts, Bacillus mucilaginosus 25-30 parts, Bacillus licheniformis 20-25 parts, Bacillus megaterium 10-15 parts, and Brevibacillus laterosporus 5-10 parts;

[0125] Optionally, the Bacillus subtilis can be 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, or any value between 25-30 parts, the Bacillus mucilaginosus can be 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, or any value between 25-30 parts, the Bacillus licheniformis can be 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, or any value between 20-25 parts, the Bacillus megaterium can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, or any value between 10-15 parts, the Brevibacillus laterosporus can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, or any value between 5-10 parts, by mass fraction;

[0126] It should be noted that the Bacillus mucilaginosus and the Bacillus megaterium are respectively used to further activate the residual valuable elements in the silicate tailings and the phosphorus tailings. Among them, the organic acid metabolized by the Bacillus mucilaginosus can effectively chelate and dissolve the residual quartz, potassium feldspar and mica mineral lattice structure in the carrier, release the plant available quick-acting potassium and soluble silicic acid, so as to convert the inherent and slow-acting mineral nutrient library in the carrier into a form that can be directly absorbed by plants, and further improve the utilization rate of valuable elements in the tailings. The acid phosphatase and organic acid secreted by the Bacillus megaterium can target hydrolysis of the hydroxyapatite and calcium magnesium phosphate provided by the phosphorus tailings in the carrier, and convert the insoluble phosphorus into soluble phosphate ions. At the same time, its metabolites can compete with heavy metal ions in the soil for chelating sites, reduce the fixation of phosphorus, and thus improve the utilization rate of phosphorus fertilizer.

[0127] The Bacillus subtilis, the Bacillus licheniformis and the Brevibacillus laterosporus are used to enrich the functionality of the soil conditioner, and complement the conventional tailings-based soil conditioner. Among them, the Bacillus subtilis can effectively inhibit the pathogenic fungi in the rhizosphere soil by synthesizing and secreting antibacterial lipopeptides; the Bacillus licheniformis can synthesize a large amount of exopolysaccharide and other viscous substances, on the one hand, the adhesion strength and anti-peeling ability of the agent on the surface of the adsorption layer are enhanced through hydrogen bond and ionic bond, on the other hand, it can effectively adsorb Ca 2+ , Mg 2+ ions dissolved in the initial stage of the carrier, buffer the pH fluctuation and osmotic pressure change of the local microenvironment. The Brevibacillus laterosporus can improve the biological stress resistance and niche protection, the insecticidal crystal protein produced by it has specific toxic effect on root-knot nematodes and other pests in the soil, which can significantly reduce the predation and interference loss of functional bacteria, and ensure the stability of the scale and activity of the bacteria from the biological level, and together with the above-mentioned strains, it constitutes a complete microbial community with multiple stress resistance;

[0128] B. The number of effective viable bacteria in the agent is greater than 5×10 9 CFU / g;

[0129] Optionally, the amount of bacteria in the bacterial agent can be any value ranging from 5 x 10 9 CFU / g, 6 x 10 9 CFU / g, 1 x 10 10 CFU / g, 1 x 10 11 CFU / g, or greater than 5 x 10 9 CFU / g.

[0130] C. The pH buffer includes, by mass fraction, 40-50 parts of sodium dihydrogen phosphate and 50-60 parts of disodium hydrogen phosphate.

[0131] Optionally, the pH buffer includes, by mass fraction, 40 parts of sodium dihydrogen phosphate, 45 parts of sodium dihydrogen phosphate, 50 parts of sodium dihydrogen phosphate, or any value ranging from 40-50 parts of sodium dihydrogen phosphate, 50 parts of disodium hydrogen phosphate, 55 parts of disodium hydrogen phosphate, 60 parts of disodium hydrogen phosphate, or any value ranging from 50-60 parts of disodium hydrogen phosphate.

[0132] D. The cell protective agent includes, by mass fraction, 50-70 parts of trehalose, 20-30 parts of polyvinylpyrrolidone, 15-30 parts of skimmed milk powder, and 3-5 parts of sodium ascorbate.

[0133] Optionally, the cell protective agent includes, by mass fraction, 50 parts of trehalose, 55 parts of trehalose, 60 parts of trehalose, 65 parts of trehalose, 70 parts of trehalose, or any value ranging from 50-70 parts of trehalose, 20 parts of polyvinylpyrrolidone, 25 parts of polyvinylpyrrolidone, 30 parts of polyvinylpyrrolidone, or any value ranging from 20-30 parts of polyvinylpyrrolidone, 15 parts of skimmed milk powder, 20 parts of skimmed milk powder, 25 parts of skimmed milk powder, 30 parts of skimmed milk powder, or any value ranging from 15-30 parts of skimmed milk powder, 3 parts of sodium ascorbate, 4 parts of sodium ascorbate, 5 parts of sodium ascorbate, or any value ranging from 3-5 parts of sodium ascorbate.

[0134] E. The nutritional activator includes, by mass fraction, 60-70 parts of glucose, 30-40 parts of yeast extract powder, and 3-5 parts of magnesium sulfate.

[0135] Optionally, the nutritional activator includes, by mass fraction, 60 parts of glucose, 65 parts of glucose, 70 parts of glucose, or any value ranging from 60-70 parts of glucose, 30 parts of yeast extract powder, 35 parts of yeast extract powder, 40 parts of yeast extract powder, or any value ranging from 30-40 parts of yeast extract powder, 3 parts of magnesium sulfate, 4 parts of magnesium sulfate, 5 parts of magnesium sulfate, or any value ranging from 3-5 parts of magnesium sulfate.

[0136] In some embodiments, the microbial load-based silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on the synergistic activation of double tailings satisfies at least one of the following conditions:

[0137] A. The thickness of the protective layer is 30-50 μm.

[0138] Optionally, the thickness of the protective layer can be 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, or any value ranging from 30-50 μm.

[0139] It should be noted that the film of the protective layer is too thick, which is easy to cause the carrier-coating layer to peel off, and too thin, which can not achieve the expected effect, the adsorption film is relatively thick to accommodate the bacterial agent;

[0140] B. the thickness of the adsorption layer is 50-70pm;

[0141] Optionally, the thickness of the adsorption layer can be 50pm, 55pm, 60pm, 65pm, 70pm or any value between 50-70pm;

[0142] C. the thickness of the fixed layer is 15-30pm;

[0143] Optionally, the thickness of the fixed layer can be 15pm, 20pm, 25pm, 30pm or any value between 15-30pm;

[0144] The second aspect of the present application provides a preparation method of the microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation, comprising:

[0145] S1: first mixing phosphorus tailings, silicate type tailings and pore forming agent to obtain a first mixture, and spraying a binder solution to the first mixture for granulation, first drying, calcination and cooling to obtain a porous carrier;

[0146] S2: second mixing the porous carrier and a first coating liquid to obtain a first coated carrier, and third mixing the first coated carrier and a first cross-linking liquid to obtain a protective layer coated carrier after second drying;

[0147] S3: fourth mixing the protective layer coated carrier and a second coating liquid to obtain an adsorption layer coated carrier after third drying;

[0148] S4: setting a bacterial liquid on the surface of the adsorption layer coated carrier to obtain a bacterial agent layer coated carrier after fourth drying;

[0149] S5: fifth mixing the bacterial agent layer coated carrier and a third coating liquid to obtain a third coated carrier, and sixth mixing the third coated carrier and a second cross-linking liquid to obtain a microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation after fifth drying.

[0150] In some embodiments, the preparation method of the microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation satisfies at least one of the following conditions:

[0151] A. the particle size of the phosphorus tailings, the silicate type tailings and the pore forming agent is independently less than or equal to 0.074mm;

[0152] It should be noted that the smaller the particle size of the phosphorus tailings, silicate tailings and pore-forming agent, the larger the contact area between particles, the more sufficient the reaction under high temperature conditions, the higher the effective element content, and the more uniform the pores.

[0153] B. The mass concentration of the binder solution is 3.0%-8.0%;

[0154] Optionally, the mass concentration of the binder solution can be 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0% or any value between 3.0% and 8.0%;

[0155] C. The rotating speed of the granulating disc is 30-40 r / min, and the granulating time is 3-5 min;

[0156] Optionally, the rotating speed of the granulating disc can be 30 r / min, 35 r / min, 40 r / min or any value between 30 r / min and 40 r / min, and the granulating time can be 3 min, 4 min, 5 min or any value between 3 min and 5 min;

[0157] It should be noted that the appropriate rotating speed and time help to improve the strength of the particles;

[0158] D. The particle size of the granulated material is 2 mm-3 mm.

[0159] Optionally, the particle size of the granulated material can be 2 mm, 2.5 mm, 3 mm or any value between 2 mm and 3 mm.

[0160] It should be noted that when the particle size of the granulated material is too large (greater than 3 mm), the surface area decreases, and the application process cannot be uniformly spread; when the particle size of the granulated material is too small (less than 2 mm), the granulating process is not convenient to operate, and the strength decreases, and the transportation process is easy to crush.

[0161] In some embodiments, the calcining includes a first calcining and a second calcining performed in sequence;

[0162] The temperature of the first calcining is 800-950℃, and the holding time is 30-120 min;

[0163] Optionally, the temperature of the first calcining can be 800℃, 850℃, 900℃, 950℃ or any value between 800℃ and 950℃, and the holding time can be 30 min, 60 min, 90 min, 120 min or any value between 30 min and 120 min;

[0164] The temperature of the second calcining is 1100-1200℃, and the holding time is 30-60 min.

[0165] Optionally, the temperature of the second calcination can be 1100℃, 1150℃, 1200℃, or any value between 1100-1200℃, and the time can be 30min, 40min, 50min, 60min, or any value between 30-60min.

[0166] It should be noted that two-stage calcination is adopted, in the low-temperature stage (first calcination), dolomite is preferentially decomposed and a uniform pore framework is formed, and in the high-temperature stage (second calcination), the pore structure is utilized to promote the efficient generation of silicates, avoiding the violent thermal decomposition reaction caused by high temperature in the first stage, which may cause local uneven large pores and reduce the specific surface area, thereby affecting the loading of the microbial agent.

[0167] In some embodiments, the preparation method of the microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation satisfies at least one of the following conditions:

[0168] A. The mass ratio of the porous carrier to the first coating liquid is 1:5-8; and the mass ratio of the porous carrier to the first cross-linking liquid is 1:5-8;

[0169] Optionally, the mass ratio of the porous carrier to the first coating liquid can be 1:5, 1:6, 1:7, 1:8, or any value between 1:5-8; and the mass ratio of the porous carrier to the cross-linking liquid can be 1:5, 1:6, 1:7, 1:8, or any value between 1:5-8.

[0170] B. The mass ratio of the porous carrier to the second coating liquid is 1:5-8;

[0171] Optionally, the mass ratio of the porous carrier to the second coating liquid can be 1:5, 1:6, 1:7, 1:8, or any value between 1:5-8.

[0172] C. The mass ratio of the porous carrier to the microbial liquid is 3-5:1;

[0173] Optionally, the mass ratio of the porous carrier to the microbial liquid can be 3:1, 4:1, 5:1, or any value between 3-5:1.

[0174] D. The mass ratio of the porous carrier to the third coating liquid is 1:5-8; and the mass ratio of the porous carrier to the second cross-linking liquid is 1:5-8;

[0175] Optionally, the mass ratio of the porous carrier to the third coating liquid can be 1:5, 1:6, 1:7, 1:8, or any value between 1:5-8; and the mass ratio of the porous carrier to the second cross-linking liquid can be 1:5, 1:6, 1:7, 1:8, or any value between 1:5-8.

[0176] E. The time of the second mixing, the third mixing, the fourth mixing and the fifth mixing is independently 5-10 min;

[0177] Optionally, the time of the second mixing, the third mixing, the fourth mixing and the fifth mixing can be independently 5 min, 6 min, 7 min, 8 min, 9 min, 10 min or any value between 5-10 min;

[0178] F. The temperature of the first drying, the second drying, the third drying, the fourth drying and the fifth drying is independently 40-50℃, and the time is independently 10-30 min.

[0179] Optionally, the temperature of the first drying, the second drying, the third drying, the fourth drying and the fifth drying can be independently 40℃, 45℃, 50℃ or any value between 40-50℃.

[0180] The embodiments of the present application will be described in detail below with specific examples, but those skilled in the art will understand that the following examples are only for illustration of the present application, and should not be regarded as limiting the scope of the present application. The specific conditions are not specified in the examples, which are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, which are all conventional products that can be purchased on the market.

[0181] Example 1

[0182] The first aspect of the present embodiment provides a microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation, which comprises a porous carrier and a protective layer, an adsorption layer, a microbial agent layer and a fixed layer arranged in sequence on the surface of the porous carrier. The thickness of the protective layer is 30 μm, the thickness of the adsorption layer is 50 μm, and the thickness of the fixed layer is 15 μm.

[0183] The raw materials of the porous carrier include, by mass fraction: 50 parts of phosphorus tailings, 50 parts of silicate type tailings, 8 parts of pore forming agent, and 10 parts of binder solution; wherein the content of dolomite in the phosphorus tailings is 74.4%, and the content of hydroxyapatite is 15.2%; the silicate type tailings are copper tailings, the content of SiO2 is 62.0%, and the content of K2O is 7.25%; the particle size of the solid raw materials is less than 0.074 mm.

[0184] The raw materials of the protective layer are a first coating liquid and a first cross-linking liquid, the first coating liquid is a water solution of sodium alginate with a mass concentration of 2.0%, chitosan with a mass concentration of 1.0%, glycerol with a mass concentration of 1.0%, and sodium dihydrogen phosphate with a mass concentration of 1.0%, and the first cross-linking liquid is a calcium chloride water solution with a mass concentration of 2.0%;

[0185] The raw material of the adsorption layer is a second coating liquid, and the second coating liquid is a water solution with a mass concentration of 2.0% chitosan, 1.0% humic acid and 1.0% acetic acid;

[0186] The raw material of the microbial agent layer is a bacterial liquid, and the raw material of the bacterial liquid includes, in mass parts, 55 parts of granular microbial agent, 20 parts of pH buffer, 15 parts of cell protective agent, 5 parts of nutritional activator and 200 parts of deionized water, and the pH value is 6.5;

[0187] The granular microbial agent (with a viable bacterial amount greater than 5 x 10 9 CFU / g) includes, in mass parts, 25 parts of Bacillus subtilis, 25 parts of Bacillus mycoides, 20 parts of Bacillus licheniformis, 10 parts of Bacillus megaterium and 5 parts of Brevibacillus laterosporus; the pH buffer includes, in mass parts, 50 parts of sodium dihydrogen phosphate and 50 parts of disodium hydrogen phosphate; the cell protective agent includes 50 parts of trehalose, 20 parts of polyvinylpyrrolidone, 25 parts of skimmed milk powder and 5 parts of sodium ascorbate; and the nutritional activator includes, in mass parts, 60 parts of glucose, 35 parts of yeast extract powder and 5 parts of magnesium sulfate.

[0188] The raw material of the fixed layer is a third coating liquid and a second cross-linking liquid, the third coating liquid is a water solution of sodium alginate with a mass concentration of 1.0%, and the second cross-linking liquid is a water solution of calcium chloride with a mass concentration of 2.0%.

[0189] The second aspect of the embodiment provides a preparation method of a microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation, and a flowchart is shown in Figure 1 The preparation method specifically includes the following steps.

[0190] S1: The phosphorus tailings, silicate tailings and pore-forming agent are uniformly mixed and ground in a ball mill to below 0.074 mm to obtain a mixed sample, and a starch binder solution with a mass concentration of 3.0% and in the above mass parts is added to the mixed sample, and wet balling is performed in a disc balling machine, the disc rotation speed is 35 r / min during the balling process, the balling time is 4 min, and the particle size is 3 mm;

[0191] S2: The dried particles are calcined in a muffle furnace, the first-stage calcination temperature is 850 DEG C, the calcination time is 60 min, the second-stage calcination temperature is 1200 DEG C, the calcination time is 30 min, and then rapid cooling is performed in air to obtain a porous carrier material;

[0192] S3: The porous carrier is immersed in the first coating liquid and is placed for 5 min, the mass ratio of the porous carrier to the first coating liquid is 1:5, the excess liquid is drained, and then the porous carrier is immersed in the cross-linking liquid according to a mass ratio of 1:5, is placed for 5 min, is washed with deionized water, and is dried at 40 DEG C for 20 min to obtain a carrier coated with a protective layer;

[0193] S4: The protective layer coated carrier is immersed in the second coating liquid and left for 5 min, the mass ratio of the porous carrier to the second coating liquid is 1:5, the excess liquid is drained, and then the porous carrier is taken out, and dried at 40 DEG C for 20 min to obtain the adsorption layer coated carrier;

[0194] S5: The above-mentioned bacterial liquid is sprayed on the surface of the adsorption layer coated carrier, wherein the mass ratio of the bacterial liquid to the porous carrier is 1:3, and the bacterial agent layer coated carrier is obtained after drying at 40 DEG C for 20 min;

[0195] S6: The bacterial agent layer coated carrier is immersed in the third coating liquid and left for 5 min, the mass ratio of the porous carrier to the third coating liquid is 1:5, the excess liquid is drained, and then the porous carrier is taken out, and dried at 40 DEG C for 20 min to obtain the third coating carrier, the third coating carrier is immersed in the second cross-linking liquid and left for 5 min, the mass ratio of the porous carrier to the second cross-linking liquid is 1:5, then the porous carrier is washed with deionized water, and dried at 40 DEG C for 20 min to obtain the microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation.

[0196] Example 2

[0197] The difference from example 1 is that the silicate type tailings is replaced by iron tailings, wherein the SiO2 content of the iron tailings is 71.42%, and the K2O content is 5.25%.

[0198] Example 3

[0199] The difference from example 1 is that in the S2 step, the first stage calcination temperature is 900 DEG C, and the holding time is 30 min; the second stage calcination temperature is 1200 DEG C, and the holding time is 30 min.

[0200] Example 4

[0201] The difference from example 1 is that the first coating liquid is a water solution of 2.0% sodium alginate, 0.5% chitosan, 0.5% glycerol and 0.5% sodium dihydrogen phosphate;

[0202] Example 5

[0203] The difference from example 1 is that the second coating liquid is a water solution of 3.0% chitosan, 0.5% humic acid and 2.0% acetic acid;

[0204] Comparative example 1

[0205] The difference from example 1 is that the phosphorus tailings with low dolomite and hydroxyapatite content is selected, wherein the dolomite content is 32.19%, and the hydroxyapatite content is 2.06%.

[0206] Comparative example 2

[0207] The difference from Example 1 is that a silicate type tailings (lead-zinc tailings) with lower SiO2 and K2O content is selected. The mass content of SiO2 is 30.52%, and the mass content of K2O is 3.29%.

[0208] Comparative Example 3

[0209] The difference from Example 1 is that no silicate type tailings is added.

[0210] Comparative Example 4

[0211] The difference from Example 1 is that no phosphorus tailings is added.

[0212] Comparative Example 5

[0213] The difference from Example 1 is that no pore-forming agent is added.

[0214] Comparative Example 6

[0215] The difference from Example 1 is that in the S2 step, the temperature of the two-stage calcination is lower than the limiting temperature. The temperature of the first-stage calcination is 600°C, and the holding time is 60 min; the temperature of the second-stage calcination is 1000°C, and the holding time is 60 min.

[0216] Comparative Example 7

[0217] The difference from Example 1 is that no protective layer is set.

[0218] Comparative Example 8

[0219] The difference from Example 1 is that the coating order of the protective layer and the adsorption layer is replaced.

[0220] Comparative Example 9

[0221] The difference from Example 1 is that no adsorption layer is set.

[0222] Comparative Example 10

[0223] The difference from Example 1 is that no microbial agent layer is set.

[0224] Comparative Example 11

[0225] The difference from Example 1 is that no fixation layer is set.

[0226] The effective components, effective viable bacteria amount, and 30-day survival rate of the microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation prepared in the above examples and comparative examples are tested, and the specific results are shown in Table 1.

[0227] Table 1 Microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on double tailings synergistic activation

[0228]

[0229] Analysis:

[0230] From Examples 1-5, it can be seen that the effective element content, the number of effective live bacteria, and the 30-day survival rate of the soil conditioner products prepared by adjusting the types of raw materials, the roasting system, the coating liquid formula, and other conditions within the scope defined in the application all meet the defined requirements.

[0231] From Comparative Example 1, it can be seen that when the content of dolomite and hydroxyapatite in the phosphorus tailings is low, the effective silicon, calcium, potassium, magnesium, and phosphorus contents are all significantly reduced.

[0232] From Comparative Example 2, it can be seen that when the SiO2 and K2O contents in the silicate tailings are reduced, the effective silicon and potassium contents in the soil conditioner are significantly reduced.

[0233] From Comparative Example 3, it can be seen that without adding silicate tailings, the final soil conditioner product contains essentially no effective silicon and effective potassium, and the phosphorus element in the phosphorus tailings cannot be activated.

[0234] From Comparative Example 4, it can be seen that without adding phosphorus tailings, the final soil conditioner product contains essentially no effective calcium, effective magnesium, and effective phosphorus elements, and the silicon and potassium elements in the silicate tailings cannot be activated.

[0235] From Comparative Example 5, it can be seen that without adding the pore-forming agent, the effective phosphorus and effective potassium contents in the final soil conditioner product are slightly reduced, and the number of effective live bacteria is significantly reduced.

[0236] From Comparative Example 6, it can be seen that when the first-stage roasting temperature is too low, it will affect the construction of the pore structure of the carrier, and in turn affect the live bacteria load, and when the second-stage roasting temperature is too low, the effective elements in the silicate tailings and the phosphorus tailings cannot be activated.

[0237] From Comparative Example 7, it can be seen that without setting the protective layer, the survival rate of the bacteria is significantly reduced.

[0238] From Comparative Example 8, it can be seen that after exchanging the positions of the protective layer and the adsorption layer, the number of effective live bacteria and the survival rate of the bacteria are both significantly reduced.

[0239] From Comparative Example 9, it can be seen that without setting the adsorption layer, the bacteria adsorption is affected, and the number of effective live bacteria is significantly reduced.

[0240] From Comparative Example 10, it can be seen that without adding the bacteria layer, it does not affect the content of the valuable elements in the soil conditioner, but there are no effective live bacteria in the soil conditioner.

[0241] From Comparative Example 11, it can be seen that without adding the fixing layer, the number of effective live bacteria and the survival rate of the bacteria are slightly reduced.

[0242] A soil improvement test was performed on the microbial load type silicon-calcium-potassium-magnesium-phosphorus soil conditioner based on the double tailings synergistic activation prepared in the above examples and comparative examples. 1 kg of soil was weighed in each test, 5 g of soil conditioner was applied, and after uniform stirring, it was placed in a plastic pot, 200 g of deionized water was added, and it was incubated at room temperature for 30 days (water was supplemented every 3 days according to the mass loss), the contents of available silicon, available calcium, available potassium, available magnesium and available phosphorus in the soil were measured, and the results are shown in Table 2. Then 6 soybean seeds were sown in each pot, water was supplemented every 3 days according to the mass loss, and after 30 days, the soybean seedlings were dried in an oven, and the dry weight was measured, and the results are shown in Table 2.

[0243] Table 2 Soil incubation and planting test results

[0244]

[0245] As can be seen from the blank group and examples 1-5, the soil conditioner sample provided by the present application can significantly increase the contents of available silicon, available calcium, available potassium, available magnesium and available phosphorus in the soil, and can promote the growth of soybean plants and increase the dry weight of crops. As can be seen from comparative examples 1-6, adjusting the types of raw materials, the ratio of raw materials and the calcination system of the porous carrier outside the defined conditions will seriously affect the effect of the soil conditioner; as can be seen from comparative examples 7-11, when the loading amount and survival rate of the microbial agent are low, it will affect the effect of the soil conditioner on increasing the contents of available silicon, available potassium and available phosphorus in the soil, and on the other hand, it will affect the growth of crops, indicating that the improvement effect of the porous carrier after loading the microbial agent is significantly improved.

[0246] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0247] In addition, those skilled in the art can understand that although some embodiments herein include certain features included in other embodiments rather than other features, the combination of features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the above claims, any one of the claimed embodiments can be used in any combination. The information disclosed in the BACKGROUND section is only intended to deepen the understanding of the overall background of the present application, and should not be considered as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. A microbial load based on double tailings synergistically activated silicon calcium potassium magnesium soil conditioner, characterized in that, The porous carrier, a protective layer, an adsorption layer, a microbial agent layer and a fixed layer are sequentially arranged on the surface of the porous carrier; The raw material of the porous carrier comprises phosphorus tailings, silicate type tailings, a pore forming agent and a binder solution; the pore forming agent comprises citric acid and straw powder, and the binder solution comprises an aqueous solution of one or more of polyvinyl alcohol, starch and humic acid; The raw material of the protective layer comprises a first coating liquid and a first cross-linking liquid, and the first coating liquid comprises an aqueous solution of sodium alginate, chitosan, glycerol and sodium dihydrogen phosphate; The raw material of the adsorption layer comprises a second coating liquid, and the second coating liquid comprises an aqueous solution of chitosan, humic acid and acetic acid; The raw material of the microbial agent layer comprises a microbial agent liquid, and the microbial agent liquid comprises a microbial agent, a pH buffer, a cell protective agent, a nutritional activator and water; The raw material of the fixed layer comprises a third coating liquid and a second cross-linking liquid; The third coating liquid is an aqueous solution of sodium alginate, and the first cross-linking liquid and the second cross-linking liquid comprise an aqueous solution of calcium chloride; the mass content of dolomite in the phosphorus tailings is ≥50%, and the mass content of hydroxyapatite is ≥10%; The mass content of SiO2 in the silicate type tailings is ≥40%, and the mass content of K2O is ≥5%; The raw material of the pore forming agent comprises, by mass fraction: citric acid 30-50 parts, and straw powder 50-70 parts; The raw material of the porous carrier comprises, by mass fraction: phosphorus tailings 50-70 parts, silicate type tailings 30-50 parts, pore forming agent 8-15 parts, and binder solution 10-20 parts; The effective state SiO2 mass content is ≥25%, the effective state CaO mass content is ≥20%, the effective state MgO mass content is ≥8%, the effective state P2O5 mass content is ≥5%, the effective state K2O mass content is ≥2%, the effective active bacteria number is ≥1×10 8 CFU / g, and the survival rate of the microbial agent is ≥85% within 30 days.

2. The dual tailings based synergistically activated microbial loaded silicon calcium potassium magnesium clay soil conditioner as claimed in claim 1, wherein, At least one of the following conditions is met: A. In the first coating liquid, the mass concentration of sodium alginate is 1.0%-2.0%, the mass concentration of chitosan is 0.5%-1.0%, the mass concentration of glycerol is 0.5%-1.0%, and the mass concentration of sodium dihydrogen phosphate is 0.5%-1.0%; B. In the second coating liquid, the mass concentration of chitosan is 2.0%-3.0%, the mass concentration of humic acid is 0.5%-1.0%, and the mass concentration of acetic acid is 0.5%-2.0%; C. In the raw material of the fixed layer, the mass concentration of the aqueous solution of sodium alginate is 1.0%-2.0%; D. In the first cross-linking liquid and the second cross-linking liquid, the mass concentration of calcium chloride is independently 2.0%-5.0%.

3. The dual tailings based synergistically activated microbial loaded silicon calcium potassium magnesium clay soil conditioner as claimed in claim 1, wherein, At least one of the following conditions is met: A. The microbial agent liquid comprises, by mass fraction: the microbial agent 55-70 parts, the pH buffer 10-20 parts, the cell protective agent 10-15 parts, the nutritional activator 5-10 parts, and water 200-300 parts; B. The pH value of the microbial agent liquid is 6.5-7.

5.

4. The dual tailings synergistically activated microbial loaded silicon calcium potassium magnesium clay soil conditioner as claimed in claim 1, wherein, At least one of the following conditions is met: A. The microbial agent comprises, by mass fraction: B. The number of effective viable bacteria in the bacterial agent is greater than 5 x 10 9 CFU / g; Bacillus subtilis 25-30 parts, Bacillus mycoides 25-30 parts, Bacillus licheniformis 20-25 parts, Bacillus megaterium 10-15 parts, and Brevibacillus laterosporus 5-10 parts; C. The pH buffer comprises, by mass fraction: sodium dihydrogen phosphate 40-50 parts, and disodium hydrogen phosphate 50-60 parts. D. The cell protective agent comprises, by mass fraction: trehalose 50-70 parts, polyvinylpyrrolidone 20-30 parts, skimmed milk powder 15-30 parts, sodium ascorbate 3-5 parts; E. The nutritional activator comprises, by mass fraction: glucose 60-70 parts, yeast extract powder 30-40 parts, magnesium sulfate 3-5 parts.

5. The dual-tailings based synergistically activated microbial loaded silicon calcium potassium magnesium clay soil conditioner according to any one of claims 1-4, characterized in that, At least one of the following conditions is met: A. The thickness of the protective layer is 30-50 μm; B. The thickness of the adsorption layer is 50-70 μm; C. The thickness of the fixed layer is 15-30 μm.

6. A process for the preparation of a dual-tailings based synergistically activated microbial loaded silicon calcium potassium magnesium clay soil conditioner as claimed in any one of claims 1-5, characterized in that, Comprise: S1: First mixing of phosphorus tailings, silicate tailings and pore forming agent to obtain a first mixture, spraying binder solution to the first mixture for granulation, first drying, calcination and cooling to obtain a porous carrier; S2: Second mixing of the porous carrier and a first coating liquid to obtain a first coated carrier, third mixing of the first coated carrier and a cross-linking liquid, and second drying to obtain a protective layer coated carrier; S3: Fourth mixing of the protective layer coated carrier and a second coating liquid, and third drying to obtain an adsorption layer coated carrier; S4: Setting a bacteria liquid on the surface of the adsorption layer coated carrier, and fourth drying to obtain a bacteria agent layer coated carrier; S5: Fifth mixing of the bacteria agent layer coated carrier and a third coating liquid to obtain a third coated carrier, sixth mixing of the third coated carrier and a cross-linking liquid, and fifth drying to obtain a microbial load type silicon calcium potassium magnesium phosphorus soil conditioner based on double tailings synergistic activation; The calcination comprises first calcination and second calcination in sequence; The temperature of the first calcination is 800-950℃, and the holding time is 30-120 min; The temperature of the second calcination is 1100-1200℃, and the holding time is 30-60 min.

7. The process for the preparation of a dual tailings based synergistically activated microbial loaded silicon calcium potassium magnesium clay soil conditioner as claimed in claim 6, wherein, At least one of the following conditions is met: A. The particle size of the phosphorus tailings, the silicate tailings and the pore forming agent is independently less than or equal to 0.074 mm; B. The mass concentration of the binder solution is 3.0%-8.0%; C. The disc rotation speed of the granulation is 30-40 r / min, and the granulation time is 3-5 min; D. The particle size of the granulated material is 2 mm-3 mm.

8. The process for the preparation of a dual tailings based synergistically activated microbial loaded silicon calcium potassium magnesium clay soil conditioner as claimed in claim 6 or 7, wherein, At least one of the following conditions is met: A. The mass ratio of the porous carrier to the first coating liquid is 1:5-8, and the mass ratio of the porous carrier to the first cross-linking liquid is 1:5-8; B. The mass ratio of the porous carrier to the second coating liquid is 1:5-8; C. The mass ratio of the porous carrier to the bacteria liquid is 3-5:1; D. The mass ratio of the porous carrier to the third coating liquid is 1:5-8, and the mass ratio of the porous carrier to the second cross-linking liquid is 1:5-8; E. The time of the second mixing, the third mixing, the fourth mixing and the fifth mixing is independently 5-10 min; F. The temperature of the first drying, the second drying, the third drying, the fourth drying and the fifth drying is independently 40-50℃, and the time is independently 10-30 min.

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