Method for preparing multi-element compound fertilizer by synergy of electrolytic manganese residues and carbide slag and compound fertilizer

Abstract

The invention provides a method for preparing a multi-element compound fertilizer from electrolytic manganese residues and carbide slag and the compound fertilizer, and relates to the technical field of comprehensive utilization of solid wastes. According to the method for preparing the multi-element compound fertilizer from the electrolytic manganese residues and the carbide slag, the electrolytic manganese residues serve as a main matrix, the carbide slag is added to recover ammonia nitrogen, then a mixture of the electrolytic manganese residues and the carbide slag is subjected to high-temperature roasting, Si, K and other components in the electrolytic manganese residues are activated, SO2 is recovered through an ammonia nitrogen solution and converted into ammonium sulfate, and the multi-element compound fertilizer is obtained. And mixing with the activated electrolytic manganese residue, and granulating to prepare the multi-element compound fertilizer. The multi-element compound fertilizer can provide N, Ca, S and Mn elements necessary for plant growth and Si element necessary for soil structure improvement, can effectively overcome the problem of weak strength of fertilizer particles, realizes reasonable conversion from solid wastes to fertilizer products, and improves the added value of the solid wastes.

Description

Technical Field

[0001] The present application relates to the technical field of comprehensive utilization of solid waste, and particularly to a method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag, and the compound fertilizer. Background Art

[0002] Electrolytic manganese residue is a solid waste generated during the production of metallic manganese. According to statistics, for every 1t of metallic manganese produced, 5 - 6 tons of electrolytic manganese residue will be discharged. For every 1t of electrolytic manganese produced, 82.78kg of liquid ammonia is added, and finally 36.5kg remains in the manganese residue, which is equivalent to 44.09% of the ammonia loss in the manganese residue. At present, electrolytic manganese enterprises mainly adopt the method of building dams for storage, which not only occupies precious land resources, but also has potential environmental pollution risks, seriously endangering the property and personal safety of the surrounding people. The composition of electrolytic manganese residue is complex, mainly containing elements such as ammonia, manganese, iron, silicon, magnesium, calcium, sulfur, etc., resulting in difficulties in its resource utilization.

[0003] Carbide slag is an alkaline waste residue generated after the hydrolysis of carbide to obtain acetylene gas. It is mainly composed of CaO and contains a small amount of components such as CaCO3, SiO2, Al2O3, etc. At present, the annual output of carbide slag in China has exceeded 28 million tons. The storage and disposal problems of carbide slag have long troubled the green and healthy development of enterprises.

[0004] At present, the comprehensive utilization of electrolytic manganese residue and carbide slag mainly focuses on the building materials direction, lacking a truly high-value utilization technology direction, and failing to fully utilize the remaining value of electrolytic manganese residue and carbide slag. Summary of the Invention

[0005] The purpose of the present application is to provide a method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag, and the compound fertilizer, aiming to solve the problem that the comprehensive utilization of existing electrolytic manganese residue and carbide slag fails to fully utilize the remaining value.

[0006] To achieve the above purpose, the present application provides a method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag, including: Mix the electrolytic manganese residue and carbide slag, add distilled water, and perform sealed stirring to obtain a precursor A, and collect the gas escaping during the stirring process with distilled water to obtain a solution R1; Dry and crush the precursor A to obtain a material B; Preheat, roast, and grind the material B to obtain a sample C, and use the solution R1 to absorb the gas generated during the roasting process, and simultaneously introduce oxygen to obtain a solution R2; Mix the sample C with the solution R2, and granulate and form to obtain the multi-element compound fertilizer.

[0007] In some embodiments, the mass ratio of the electrolytic manganese residue to the carbide slag is (4.5 - 6.5):2. The addition amount of the primary carbide slag is 85 - 90% of the total amount, and the addition amount of the secondary carbide slag is 10 - 15% of the total amount.

[0008] In some embodiments, the stirring speed is 50 r / min - 100 r / min, the stirring time is 55 min - 110 min, and the dosage of distilled water is 40% - 55% of the total mass of the mixture of the electrolytic manganese residue and the carbide slag.

[0009] In some embodiments, the drying temperature is 70°C - 95°C, the drying is carried out until the water content is less than 5%, and the particle size range of the crushing is 0.074 mm - 0.300 mm.

[0010] In some embodiments, the preheating temperature is 240°C - 350°C, the preheating time is 1 h - 2 h, the roasting temperature is 1200°C - 1350°C, and the roasting time is 20 min - 55 min.

[0011] In some embodiments, the particle size range of the grinding is 0.10 mm - 0.20 mm; the volume percentage concentration of oxygen is 30% - 50%.

[0012] In some embodiments, before the solution R2 is mixed with the sample C, first concentrate or dilute (NH4)2SO4 in the solution R2 to a solution with a mass percentage of 15% - 25%; The mixing mass ratio of the sample C to the concentrated or diluted solution R2 is (9 - 11):1.

[0013] In some embodiments, the granulation is extrusion granulation, and the pressure range of the extrusion granulation is 10 MPa - 40 MPa.

[0014] In some embodiments, after the granulation and forming, the particles are screened, dried, and cooled. The particle size range of the screening is 2.35 mm - 4.25 mm, the drying temperature is 120°C - 200°C, and the water content after drying is 0 - 1.5%.

[0015] This application also provides a multi - element compound fertilizer, which is prepared by the method of preparing a multi - element compound fertilizer by using the above - mentioned electrolytic manganese residue in cooperation with carbide slag.

[0016] Compared with the prior art, the beneficial effects of this application include: The method for preparing a multi-element compound fertilizer by using electrolytic manganese residue in cooperation with carbide slag provided by this application uses electrolytic manganese residue as the main matrix, adds carbide slag to recover ammonia nitrogen, then calcines the mixture of electrolytic manganese residue and carbide slag at high temperature to activate components such as Si and K in the electrolytic manganese residue, and uses the ammonia nitrogen solution to recover SO2 and convert it into (NH4)2SO4, which is mixed with the activated electrolytic manganese residue and granulated to prepare a multi-element compound fertilizer. The method for preparing a multi-element compound fertilizer provided by this application can provide the N, Ca, S, and Mn elements necessary for plant growth and the Si element required for improving soil structure. At the same time, it can effectively overcome the problem of weak strength of fertilizer particles, realize the reasonable conversion of solid waste into fertilizer products, and improve the product added value of solid waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as limiting the scope of this application.

[0018] Figure 1 It is a process schematic diagram of the method for preparing a multi-element compound fertilizer by using electrolytic manganese residue in cooperation with carbide slag of this application; Figure 2 It is an operation process schematic diagram of the method for preparing a multi-element compound fertilizer by using electrolytic manganese residue in cooperation with carbide slag in Example 1; Figure 3 It is an SEM image of the electrolytic manganese residue used in this application; Figure 4 It is an SEM image of the multi-element compound fertilizer in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] As used herein, the terms: "prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing" or any other variation thereof used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or device containing the recited elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article or device.

[0020] The connecting word "consisting of" excludes any unstated element, step or component. If used in a claim, this phrase will render the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the claim body rather than immediately following the subject, it only limits the elements described in that clause; other elements are not excluded from the claim as a whole.

[0021] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed individually. For example, when the range "1 to 5" is disclosed, the described range should be interpreted as including the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range.

[0022] In these examples, unless otherwise specified, the parts and percentages are by mass.

[0023] "Part by mass" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1 g or 2.689 g, etc. If we say that the mass part of component A is a parts and the mass part of component B is b parts, it means the mass ratio of component A to component B is a:b. Or, it means the mass of component A is aK and the mass of component B is bK (K is any number representing a multiple factor). It should not be misunderstood that, different from the number of mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0024] This application provides a method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese slag and carbide slag. Please refer to Figure 1 , including: S100: Mix the electrolytic manganese slag and carbide slag, add distilled water, and conduct sealed stirring to obtain precursor A, and collect the gas escaping during the stirring process using distilled water to obtain solution R1; S200: Dry and crush precursor A to obtain material B; S300: Preheat, roast, and grind material B to obtain sample C, and use solution R1 to absorb the gas generated during the roasting process, while introducing oxygen to obtain solution R2; S400: Mix sample C with solution R2 and granulate to form a multi-element compound fertilizer.

[0025] The method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag provided by this application uses electrolytic manganese residue as the main matrix, adds carbide slag to recover ammonia nitrogen, and then calcines the mixture of electrolytic manganese residue and carbide slag at a high temperature to activate components such as Si and K in the electrolytic manganese residue. At the same time, uses the ammonia nitrogen solution to recover SO2 and convert it into (NH4)2SO4, which is mixed with the activated electrolytic manganese residue and granulated to prepare a multi-element compound fertilizer. The method for preparing a multi-element compound fertilizer provided by this application can provide the N, Ca, S, and Mn elements necessary for plant growth and the Si element required for improving soil structure. At the same time, it can effectively overcome the problem of weak strength of fertilizer particles, realize the reasonable conversion of solid waste into fertilizer products, and improve the product added value of solid waste.

[0026] In some embodiments, the leachable NH4 in the electrolytic manganese residue in step S100 + content ≥ 1800 mg / kg, SiO2 content ≥ 32%, the pH value range of carbide slag is 12.5 - 14.0, and the calcium carbonate content ≥ 8%.

[0027] In some embodiments, the mass ratio of the electrolytic manganese residue to the carbide slag in step S100 is (4.5 - 6.5):2. For example, it can be 4.5:2, 5.0:2, 5.5:2, 6.0:2, 6.5:2 or any ratio between (4.5 - 6.5):2. The addition amount of the primary carbide slag is 85 - 90% of the total amount, and the addition amount of the secondary carbide slag is 10 - 15% of the total amount.

[0028] In some embodiments, the stirring speed in step S100 is 50 r / min - 100 r / min. For example, it can be 50 r / min, 60 r / min, 70 r / min, 80 r / min, 90 r / min, 100 r / min or any value between 50 r / min - 100 r / min. The stirring time is 55 min - 110 min. For example, it can be 55 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or any value between 55 min - 110 min. The dosage of distilled water mixed with the mixture of electrolytic manganese residue and carbide slag in step S100 is 40% - 55% of the total mass of the mixture of electrolytic manganese residue and carbide slag. For example, it can be 40%, 45%, 50%, 55% or any value between 40% - 55%.

[0029] In some embodiments, after mixing the electrolytic manganese residue and the carbide slag in step S100, distilled water is added for sealed stirring to release ammonia gas, and the gas escaping during the stirring process is collected by distilled water to obtain solution R1, that is, ammonia water.

[0030] In some embodiments, the drying temperature in step S200 is 70°C - 95°C. For example, it can be 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, or any value between 70°C - 95°C. It is dried until the water content is less than 5%. For example, it can be 1%, 2%, 3%, 4%, 4.5%, or any value less than 5%. The particle size range of the crushed material is 0.074 mm - 0.300 mm. For example, it can be 0.074 mm, 0.080 mm, 0.085 mm, 0.090 mm, 0.095 mm, 0.100 mm, 0.150 mm, 0.200 mm, 0.250 mm, 0.300 mm, or any value between 0.074 mm - 0.300 mm.

[0031] In some embodiments, the preheating temperature in step S300 is 240°C - 350°C. For example, it can be 240°C, 250°C, 260°C, 280°C, 300°C, 320°C, 330°C, 350°C, or any value between 240°C - 350°C. The preheating time is 1 h - 2 h. For example, it can be 1 h, 1.5 h, 2 h, or any value between 1 h - 2 h. The roasting temperature is 1200°C - 1350°C. For example, it can be 1200°C, 1250°C, 1300°C, 1350°C, or any value between 1200°C - 1350°C. The roasting time is 20 min - 55 min. For example, it can be 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, or any value between 20 min - 55 min.

[0032] In some embodiments, the particle size range of the grinding in step S300 is 0.10 mm - 0.20 mm. For example, it can be 0.10 mm, 0.12 mm, 0.14 mm, 0.15 mm, 0.17 mm, 0.19 mm, 0.20 mm, or any value between 0.10 mm - 0.20 mm; the volume percentage concentration of the oxygen introduced in step S300 is 30% - 50%. For example, it can be 30%, 35%, 40%, 45%, 50%, or any value between 30% - 50%.

[0033] In some embodiments, after the material B in step S300 is preheated and roasted, sulfur dioxide is released. Then, the sulfur dioxide is absorbed by the solution R1 ammonia water while oxygen is introduced to generate ammonium sulfate, that is, the solution R2. Ammonium sulfate has the effect of enhancing the particle strength for fertilizers.

[0034] In some embodiments, before the solution R2 obtained in step S300 is mixed with the sample C, the (NH4)2SO4 in the solution R2 is first concentrated or diluted to a solution with a mass percentage of 15%-25%. The mass percentage of (NH4)2SO4 in the solution R2 can be, for example, 15%, 16%, 18%, 20%, 22%, 23%, 24%, 25% or any value between 15%-25%.

[0035] In some embodiments, the mixing mass ratio of the sample C to the concentrated or diluted solution R2 in step S400 is (9-11):1. For example, it can be 9:1, 9.5:1, 10:1, 10.5:1, 11:1 or any ratio between (9-11):1.

[0036] In some embodiments, the granulation in step S400 is extrusion granulation, and the pressure range of extrusion granulation is 10 MPa to 40 MPa. For example, it can be 10 MPa, 15 MPa, 20 MPa, 25 MPa, 30 MPa, 35 MPa, 40 MPa or any value between 10 MPa and 40 MPa.

[0037] In some embodiments, after the granulation and forming in step S400, it further includes screening, drying and cooling the particles. The particle size range of the screening is 2.35 mm - 4.25 mm. For example, it can be 2.35 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.8 mm, 3.0 mm, 3.2 mm, 3.5 mm, 3.8 mm, 4.0 mm, 4.25 mm or any value between 2.35 mm and 4.25 mm. The drying temperature is 120°C - 200°C. For example, it can be 120°C, 140°C, 150°C, 160°C, 180°C, 200°C or any value between 120°C and 200°C. The moisture content after drying is 0 - 1.5%.

[0038] The present application also provides a multi-element compound fertilizer, which is prepared by the method of preparing a multi-element compound fertilizer by synergistically treating electrolytic manganese slag and carbide slag as described above.

[0039] The present application proposes the synergistic treatment of electrolytic manganese slag (rich in Si, Mn, NH4⁺) and carbide slag (highly alkaline CaO). The silicon element is activated by high-temperature roasting, and the ammonia nitrogen and SO2 are recovered by using the alkalinity of the carbide slag to form (NH4)2SO4. At the same time, heavy metals are solidified, and the gas and solid components are fully utilized during the preparation process. There is no additional secondary waste generated in the production system, realizing the green circular utilization of industrial solid waste.

[0040] The method for preparing multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag in this application solidifies the potential heavy metal pollution risks such as manganese, lead, arsenic, and cadmium in the electrolytic manganese residue in the form of elemental solid solution under high-temperature roasting conditions, realizing the harmless treatment of the electrolytic manganese residue and effectively avoiding environmental pollution.

[0041] The multi-element compound fertilizer provided in this application contains beneficial elements such as effective Si, Ca, Mn, S, and N in the product. It can not only meet the effective Si required for soil conditioning but also simultaneously meet the essential elements such as Ca, Mn, S, and N necessary for plant growth, having the dual effects of supplementing soil components and regulating plant nutrition.

[0042] This application makes full use of the high alkalinity of carbide slag to activate the "inert" Si element in electrolytic manganese residue into active-state effective Si that can be used for soil improvement and plant nutrition supplementation under high-temperature conditions, giving full play to the potential residual value of the two solid wastes.

[0043] The implementation scheme of this application will be described in detail below in combination with specific embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate this application and should not be regarded as limiting the scope of this application. For those not specifying specific conditions in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0044] Example 1 This example provides a method for preparing multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag. Please refer to Figure 2 , which includes the following steps: 1. Mix the electrolytic manganese residue (SEM diagram as shown in Figure 3 ) with carbide slag in a ratio of 4.5:2, then add distilled water accounting for 50% of the total mass of the mixture, place it in a closed stirring device, stir for 60 min at a rotation speed of 85 r / min. After stirring, obtain the precursor A, and at the same time, collect the overflowing ammonia gas with distilled water to obtain the solution R1; 2. Place the precursor A in an oven and dry it at a drying temperature of 80 °C until the water content is less than 2%, and crush the dried precursor A to a particle size of 0.150 mm to obtain the material B; 3. Place the material B in a tubular furnace, preheat it at 300 °C for 1 h, roast it at 1250 °C for 30 min, and grind the roasted sample until it completely passes through a 0.15 mm sieve to obtain the sample C. At the same time, use the solution R1 to absorb the gas generated during the roasting process, and simultaneously introduce oxygen with a volume percentage concentration of 30%. After sufficient reaction, obtain the solution R2; 4. First, concentrate or dilute (NH4)2SO4 in solution R2 to a solution with a mass fraction of 20%, and then mix sample C with solution R2 in a ratio of 10:1. Use the extrusion granulation method for forming, with a forming pressure of 30 MPa. After forming, screen the granules through a 3.25 mm sieve, dry them at 200 °C until the moisture content is 1%, and then cool them to obtain a multi-element compound fertilizer containing Si, Ca, Mn, S, N, etc. The SEM image of its surface is as shown in Figure 4 shown; 5. Detect the contents of Si, Ca, Mn, S, and N in the multi-element compound fertilizer.

[0045] Example 2 This example provides a method for preparing a multi-element compound fertilizer by using electrolytic manganese slag in coordination with carbide slag, which includes the following steps: 1. Mix electrolytic manganese slag and carbide slag in a mass ratio of 4.5:2, then add distilled water accounting for 50% of the total mass of the mixture, place it in a closed stirring device, stir for 60 min at a rotation speed of 85 r / min. After stirring, obtain precursor A, and at the same time, collect the overflowing ammonia gas with distilled water to obtain solution R1; 2. Place precursor A in an oven and dry it at a drying temperature of 80 °C until the water content is less than 2%, and then crush the dried precursor A to a particle size of 0.150 mm to obtain material B; 3. Place material B in a tubular furnace, preheat it at 300 °C for 1 h and calcine it at 1350 °C for 30 min, and then grind the calcined sample until it completely passes through a 0.15 mm sieve to obtain sample C. At the same time, use solution R1 to absorb the gas generated during the calcination process, and at the same time, introduce oxygen with a volume percentage concentration of 30%. After sufficient reaction, obtain solution R2; 4. First, concentrate or dilute (NH4)2SO4 in solution R2 to a solution with a mass fraction of 20%, and then mix sample C with the concentrated or diluted solution R2 in a ratio of 10:1. Use the extrusion granulation method for forming, with a forming pressure of 30 MPa. After forming, screen the granules through a 3.25 mm sieve, dry them at 200 °C until the moisture content is 1%, and then cool them to obtain a multi-element compound fertilizer containing Si, Ca, Mn, S, N, etc.; 5. Detect the contents of Si, Ca, Mn, S, and N in the multi-element compound fertilizer.

[0046] Example 3 This example provides a method for preparing a multi-element compound fertilizer by using electrolytic manganese slag in coordination with carbide slag, which includes the following steps: 1. Mix electrolytic manganese residue and carbide slag in a mass ratio of 6.5:2, then add distilled water accounting for 50% of the total mass of the mixture, place it in a closed stirring device, stir for 60 min at a rotation speed of 85 r / min. After stirring, obtain precursor A, and at the same time, collect the overflowing ammonia gas with distilled water to obtain solution R1; 2. Place precursor A in a drying oven, dry it at a drying temperature of 80 °C until the water content is less than 2%, and crush the dried precursor A to a particle size of 0.150 mm to obtain material B; 3. Place material B in a tubular furnace, preheat it at 300 °C for 1 h and calcine it at 1250 °C for 30 min, and grind the calcined sample until it completely passes through a 0.15 mm sieve to obtain sample C. At the same time, use solution R1 to absorb the gas generated during the calcination process, and at the same time, introduce oxygen with a volume percentage concentration of 30%. After full reaction, obtain solution R2; 4. First, concentrate or dilute (NH4)2SO4 in solution R2 to a solution with a mass fraction of 20%, and then mix sample C with the concentrated or diluted solution R2 in a ratio of 10:1, and use the extrusion granulation method for forming. The forming pressure is 30 MPa. After forming, screen the particles through a 3.25 mm sieve, dry them at 200 °C until the water content is 1%, and cool them to obtain a multi-element compound fertilizer containing Si, Ca, Mn, S, N, etc.; 5. Detect the contents of Si, Ca, Mn, S, and N in the multi-element compound fertilizer.

[0047] Example 4 This example provides a method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag, including the following steps: 1. Mix electrolytic manganese residue and carbide slag in a mass ratio of 4.5:2, then add distilled water accounting for 50% of the total mass of the mixture, place it in a closed stirring device, stir for 100 min at a rotation speed of 100 r / min. After stirring, obtain precursor A, and at the same time, collect the overflowing ammonia gas with distilled water to obtain solution R1; 2. Place precursor A in a drying oven, dry it at a drying temperature of 80 °C until the water content is less than 2%, and crush the dried precursor A to a particle size of 0.150 mm to obtain material B; 3. Place material B in a tubular furnace, preheat it at 300 °C for 1 h and calcine it at 1250 °C for 30 min, and grind the calcined sample until it completely passes through a 0.15 mm sieve to obtain sample C. At the same time, use solution R1 to absorb the gas generated during the calcination process, and at the same time, introduce oxygen with a volume percentage concentration of 30%. After full reaction, obtain solution R2; 4. First, concentrate or dilute (NH4)2SO4 in solution R2 to a solution with a mass fraction of 20%, and then mix sample C with the concentrated or diluted solution R2 at a ratio of 10:1. Use the extrusion granulation method for forming, with a forming pressure of 30 MPa. After forming, screen the granules through a 3.25 mm sieve, dry them at 200 °C until the moisture content is 1%, and then cool them to obtain a multi-element compound fertilizer containing Si, Ca, Mn, S, N, etc. 5. Detect the contents of Si, Ca, Mn, S, and N in the multi-element compound fertilizer.

[0048] Example 5 This example provides a method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese slag and carbide slag, which includes the following steps: 1. Mix electrolytic manganese slag and carbide slag according to a mass ratio of 4.5:2, then add distilled water accounting for 50% of the total mass of the mixture, place it in a closed stirring device, stir for 60 min at a rotation speed of 85 r / min. After stirring, obtain precursor A, and at the same time, collect the overflowing ammonia gas with distilled water to obtain solution R1. 2. Place precursor A in an oven and dry it at a drying temperature of 80 °C until the water content is less than 2%. Then crush the dried precursor A to a particle size of 0.150 mm to obtain material B. 3. Place material B in a tubular furnace, preheat it at 300 °C for 1 h, roast it at 1250 °C for 55 min, and then grind the roasted sample until it completely passes through a 0.15 mm sieve to obtain sample C. At the same time, use solution R1 to absorb the gas generated during the roasting process, and simultaneously introduce oxygen with a volume percentage concentration of 30%. After sufficient reaction, obtain solution R2. 4. First, concentrate or dilute (NH4)2SO4 in solution R2 to a solution with a mass fraction of 20%, and then mix sample C with the concentrated or diluted solution R2 at a ratio of 10:1. Use the extrusion granulation method for forming, with a forming pressure of 30 MPa. After forming, screen the granules through a 3.25 mm sieve, dry them at 200 °C until the moisture content is 1%, and then cool them to obtain a multi-element compound fertilizer containing Si, Ca, Mn, S, N, etc. 5. Detect the contents of Si, Ca, Mn, S, and N in the multi-element compound fertilizer.

[0049] Example 6 This example provides a method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese slag and carbide slag, which includes the following steps: 1. Mix electrolytic manganese residue and carbide slag in a mass ratio of 4.5:2, then add distilled water accounting for 50% of the total mass of the mixture, place it in a closed stirring device, stir for 100 min at a rotation speed of 100 r / min. After stirring, obtain precursor A, and at the same time, collect the overflowing ammonia gas with distilled water to obtain solution R1; 2. Place precursor A in a drying oven, dry it at a drying temperature of 90 °C until the water content is less than 2%, and crush the dried precursor A to a particle size of 0.300 mm to obtain material B; 3. Place material B in a tubular furnace, preheat it at 200 °C for 1 h and calcine it at 1250 °C for 30 min, and grind the calcined sample until it completely passes through a 0.15 mm sieve to obtain sample C. At the same time, use solution R1 to absorb the gas generated during the calcination process, and at the same time, introduce oxygen with a volume percentage concentration of 30%, and after sufficient reaction, obtain solution R2; 4. First, concentrate or dilute (NH4)2SO4 in solution R2 to a solution with a mass fraction of 20%, and then mix sample C with the concentrated or diluted solution R2 in a ratio of 10:1, and form it by extrusion granulation. The forming pressure is 30 MPa. After forming, screen the particles through a 3.25 mm sieve, dry them at 200 °C until the water content is 1%, and cool them to obtain a multi-element compound fertilizer containing Si, Ca, Mn, S, N, etc.; 5. Detect the contents of Si, Ca, Mn, S, and N in the multi-element compound fertilizer.

[0050] Example 7 This example provides a method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag, including the following steps: 1. Mix electrolytic manganese residue and carbide slag in a mass ratio of 4.5:2, then add distilled water accounting for 50% of the total mass of the mixture, place it in a closed stirring device, stir for 100 min at a rotation speed of 100 r / min. After stirring, obtain precursor A, and at the same time, collect the overflowing ammonia gas with distilled water to obtain solution R1; 2. Place precursor A in a drying oven, dry it at a drying temperature of 80 °C until the water content is less than 2%, and crush the dried precursor A to a particle size of 0.150 mm to obtain material B; 3. Place material B in a tubular furnace, preheat it at 300 °C for 1 h and calcine it at 1250 °C for 30 min, and grind the calcined sample until it completely passes through a 0.15 mm sieve to obtain sample C. At the same time, use solution R1 to absorb the gas generated during the calcination process, and at the same time, introduce oxygen with a volume percentage concentration of 50%, and after sufficient reaction, obtain solution R2; 4. First, concentrate or dilute (NH4)2SO4 in solution R2 to a solution with a mass fraction of 20%, and then mix sample C with the concentrated or diluted solution R2 in a ratio of 9:1. Use the extrusion granulation method for forming, with a forming pressure of 40 MPa. After forming, screen the particles through a 3.25 mm sieve, dry them at 200 °C until the moisture content is 0.5%, and then cool them to obtain a multi-element compound fertilizer containing Si, Ca, Mn, S, N, etc. 5. Detect the contents of Si, Ca, Mn, S, and N in the multi-element compound fertilizer.

[0051] Comparative Example 1 Comparative Example 1 provides a method for preparing a multi-element compound fertilizer by using electrolytic manganese slag in cooperation with carbide slag. The difference from Example 1 is that carbide slag is not compounded, and the raw material is only electrolytic manganese slag. Other steps and process conditions are the same as those in Example 1 and will not be elaborated here.

[0052] Comparative Example 2 Comparative Example 2 provides a method for preparing a multi-element compound fertilizer by using electrolytic manganese slag in cooperation with carbide slag. The difference from Example 1 is that the roasting temperature of material B is 800 °C. Other steps and process conditions are the same as those in Example 1 and will not be elaborated here.

[0053] Comparative Example 3 Comparative Example 3 provides a method for preparing a multi-element compound fertilizer by using electrolytic manganese slag in cooperation with carbide slag. The difference from Example 1 is that electrolytic manganese slag and carbide slag are mixed in a mass ratio of 1:1. Other steps and process conditions are the same as those in Example 1 and will not be elaborated here.

[0054] Comparative Example 4 Comparative Example 4 provides a method for preparing a multi-element compound fertilizer by using electrolytic manganese slag in cooperation with carbide slag. The difference from Example 1 is that the roasting time of material B is 10 min. Other steps and process conditions are the same as those in Example 1 and will not be elaborated here.

[0055] Comparative Example 5 Comparative Example 5 provides a method for preparing a multi-element compound fertilizer by using electrolytic manganese slag in cooperation with carbide slag. The difference from Example 1 is that the dried precursor A is not crushed. Other steps and process conditions are the same as those in Example 1 and will not be elaborated here.

[0056] Comparative Example 6 Comparative Example 6 provides a method for preparing a multi-element compound fertilizer by using electrolytic manganese slag in cooperation with carbide slag. The difference from Example 1 is that electrolytic manganese slag is not compounded, and the raw material is only carbide slag. Other steps and process conditions are the same as those in Example 1 and will not be elaborated here.

[0057] Comparative Example 7 Comparative Example 7 provides a method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese slag and carbide slag. The difference from Example 1 is that: solution R1 is used to absorb the gas generated during the roasting process, and oxygen is not introduced. Other steps and process conditions are the same as those in Example 1, and will not be elaborated here.

[0058] Comparative Example 8 Comparative Example 8 provides a method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese slag and carbide slag. The difference from Example 1 is that: extrusion granulation is used for forming, and the forming pressure is 5 MPa. Other steps and process conditions are the same as those in Example 1, and will not be elaborated here.

[0059] Performance tests were conducted on the multi-element compound fertilizers obtained in the examples and comparative examples. The specific results are shown in Table 1 and Table 2. According to Table 1 and Table 2, it can be seen that the multi-element compound fertilizer obtained by the example scheme of the present application has relatively high contents of Si and Ca elements, relatively low contents of Mn element and other heavy metal elements, and at the same time contains a small amount of Mn element necessary for plant growth. The Si element can meet the requirements for soil conditioning, and the essential elements such as Ca, Mn, S, and N can simultaneously meet the needs for plant growth. The multi-element compound fertilizer obtained in the present application has the dual effects of supplementing soil components and regulating plant nutrition.

[0060] In Comparative Example 1, since the carbide slag raw material was not added, a high-alkaline condition could not be provided, and even under high-temperature roasting conditions, the "inert" Si element in the electrolytic manganese slag could not be activated. The content of Si element in the obtained multi-element compound fertilizer was low and could not be used for soil conditioning. In the scheme of Comparative Example 2, although the carbide slag raw material was added, the roasting temperature was too low, and the "inert" Si element in the electrolytic manganese slag could not be activated either. In the scheme of Comparative Example 3, an "excessive" amount of carbide slag was added, resulting in relatively low contents of Si and N in the product, and the product value decreased. In the scheme of Comparative Example 4, the roasting time was too short, and the Si in the electrolytic manganese slag could not be fully activated. In the scheme of Comparative Example 5, since the mixture was not crushed, the internal roasting activation of the mixture would be insufficient, reducing the content of effective elements. In the scheme of Comparative Example 6, since the electrolytic manganese slag raw material was not added, Si, Mn, and N elements could not be provided. In the scheme of Comparative Example 7, since oxygen was not introduced when collecting and absorbing the gas generated during the roasting process, the yield of ammonium sulfate decreased significantly, resulting in a decrease in particle strength. In the scheme of Comparative Example 8, since the extrusion forming pressure was only 5 MPa, the strength of the fertilizer particles decreased.

[0061] Table 1 Main performance parameters of multi-element compound fertilizer

[0062] Table 2 Heavy metal element contents in multi-element compound fertilizer

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0064] In addition, those skilled in the art can understand that although some of the embodiments herein include certain features included in other embodiments rather than other features, the combination of the 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 this background section is only intended to deepen the understanding of the overall background technology of the present application, and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those skilled in the art.

Claims

1. A method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag, characterized in that, Comprising: Mix electrolytic manganese residue and carbide slag, add distilled water, carry out sealed stirring to obtain precursor A, and use distilled water to collect the gas evolved during the stirring process to obtain solution R1; Dry and crush the precursor A to obtain material B; Preheat, roast, and grind the material B to obtain sample C, and use the solution R1 to absorb the gas generated during the roasting process, and at the same time introduce oxygen to obtain solution R2; Mix the sample C and the solution R2, and granulate and form to obtain the multi-element compound fertilizer.

2. The method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag according to claim 1, characterized in that, The mass ratio of the electrolytic manganese residue to the carbide slag is (4.5 - 6.5):

2.

3. The method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag according to claim 1, wherein The stirring speed is 50 r / min - 100 r / min, the stirring time is 55 min - 110 min, and the dosage of distilled water is 40% - 55% of the total mass of the mixture of electrolytic manganese residue and carbide slag.

4. The method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag according to claim 1, characterized in that, The drying temperature is 70°C - 95°C, the drying is carried out until the water content is less than 5%, and the particle size range of the crushing is 0.074 mm - 0.300 mm.

5. The method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag according to claim 1, characterized in that The preheating temperature is 240°C - 350°C, the preheating time is 1 h - 2 h, the roasting temperature is 1200°C - 1350°C, and the roasting time is 20 min - 55 min.

6. The method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag according to claim 1, characterized in that The particle size range of the grinding is 0.10 mm - 0.20 mm; the volume percentage concentration of oxygen is 30% - 50%.

7. The method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag according to claim 1, wherein, Before the solution R2 is mixed with the sample C, first concentrate or dilute (NH4)2SO4 in the solution R2 to a solution with a mass percentage of 15% - 25%; The mixing mass ratio of the sample C to the concentrated or diluted solution R2 is (9 - 11):

1.

8. The method for preparing a multi-element compound fertilizer by using electrolytic manganese residue and carbide slag in a synergistic manner according to claim 1, wherein The granulation is extrusion granulation, and the pressure range of the extrusion granulation is 10 MPa - 40 MPa.

9. The method for preparing a multi-element compound fertilizer by using electrolytic manganese residue and carbide slag in combination according to claim 1 or 8, characterized in that, After the granulation and forming, the particles are screened, dried, and cooled. The particle size range of the screening is 2.35 mm - 4.25 mm, the drying temperature is 120°C - 200°C, and the water content after drying is 0 - 1.5%.

10. A multi-element compound fertilizer, characterized in that, Prepared by the method for preparing a multi-element compound fertilizer by synergistically using electrolytic manganese residue and carbide slag according to any one of claims 1 to 9.

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