Multi-element nutrient element supported manganese ore slow-release fertilizer as well as preparation method and application thereof

Abstract

The invention discloses a multielement nutrient element supported manganese ore slow release fertilizer as well as a preparation method and application thereof. The slow-release fertilizer comprises modified manganese ore, nutrient elements and lignin, nutrient elements are loaded in the modified manganese ore. Nutrient elements are loaded on manganese ore, so that the fertilizer which is loaded with the nutrient elements and can slowly release the nutrient elements into soil is prepared, after the fertilizer is applied to the soil, the content of the nutrient elements (including manganese, potassium, iron, calcium, copper and zinc) in the soil can be remarkably increased, specifically, the content of manganese in the soil can be increased from 0 mg / L to 7.93 mg / L to 121.9 mg / L, the content of zinc in the soil can be increased from 0.02 mg / L to 0.70 mg / L, and the content of copper in the soil can be increased from 0 mg / L to 0.00 mg / L to 0.66 mg / L; and the concentrations of iron, potassium and calcium in the soil are respectively increased by 122.8 times, 10.73 times and 5.32 times.

Description

Technical Field

[0001] The invention belongs to the field of fertilizers, and in particular relates to a multi-nutrient element loaded manganese ore slow-release fertilizer and a preparation method and application thereof. Background Art

[0002] Manganese ore is commonly used in metallurgy, batteries, chemicals, and environmental pollution remediation, and the application of manganese minerals in agricultural production is still very lacking. Manganese is an essential nutrient for plant growth, participating in photosynthesis and respiration, promoting crop growth and increasing yield. Therefore, manganese plays an important role in plant growth and yield improvement. In the past, nutrients such as manganese, potassium, calcium, zinc, copper, and iron were often directly applied to the soil in the form of inorganic salts. This method easily leads to excessive accumulation of nutrients in the soil, which has an adverse effect on the environment and crop health. Slow-release fertilizers are fertilizers that gradually release nutrients over a certain period of time, which can improve fertilizer utilization, reduce nutrient loss, stabilize plant growth, and reduce the impact on the environment. However, traditional slow-release fertilizers rely on petroleum-based polymers (such as polyurethane and polyethylene) for coating, and the raw materials are non-renewable and expensive, and microplastic pollution is generated after degradation (such as the problem of PBAT slow-release film residues). Most slow-release fertilizers are designed only for single elements such as nitrogen, phosphorus, and potassium, and cannot meet the needs of synergistic release of trace elements such as manganese, zinc, and iron. In addition, existing slow-release fertilizers are expensive and cannot achieve the loading and slow release of multiple elements. When applied to the soil, the slow-release effect is limited and cannot meet the needs of crop growth. Summary of the invention

[0003] In order to overcome at least one technical problem existing in the above-mentioned prior art, one of the objects of the present invention is to provide a slow-release fertilizer, which uses structurally stable manganese ore as a nutrient element carrier, and loads the nutrients in the tunnels and layers of the manganese ore to avoid excessive nutrient element content caused by too rapid release of the nutrients; and then regulates the release of nutrients in the manganese ore through lignin, so as to achieve slow and continuous release of nutrients, thereby providing effective nutrients for plants.

[0004] A second object of the present invention is to provide a method for preparing a slow-release fertilizer.

[0005] A third object of the present invention is to provide application of the above slow-release fertilizer in the field of fertilizers.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The invention provides a slow-release fertilizer, comprising modified manganese ore, nutrient elements and lignin; the modified manganese ore is loaded with nutrient elements.

[0008] The present invention selects manganese ore as an important storage form of nutrient elements. The manganese ore can adopt various structures such as hydromanganese ore, pyrolusite, and calmanganese ore. The tunnels and interlayers of the manganese ore have rich ion exchange sites and can be used as a storage depot for metal nutrient elements such as potassium, calcium, zinc, copper, and iron. The present invention modifies the manganese ore and then loads the metal elements so that the metal elements are loaded in the tunnels and interlayers of the manganese ore, thereby directionally regulating the content and types of nutrient elements in the manganese ore according to soil needs, so that the slow-release fertilizer is loaded with nutrient elements and can slowly release soil elements into the soil, thereby meeting the growth and development needs of plants, and avoiding excessive accumulation of nutrient elements in the soil, thereby adversely affecting the growth of plants.

[0009] In addition, manganese ore has an octahedral equicrystalline structure, and manganese forms coordination bonds with the surrounding ligand oxygen, which is relatively stable in nature. When manganese ore is modified and loaded with metal elements, the metal elements can be stored in the tunnels and interlayers of the manganese ore, in the form of ion exchange, hydrated ions, or embedded in the crystal cells of the manganese ore, which is relatively stable and not easy to release. Then, lignin is used to promote the release of nutrients loaded in the tunnels and interlayers of manganese ore, thereby increasing the content of nutrients in the soil, which can continuously provide nutrients during the growth cycle of crops and reduce the number of fertilizations and the negative impact on the environment. It is an environmentally friendly agricultural technology with significant economic benefits.

[0010] In some embodiments of the present invention, the nutrient element includes at least one of iron, manganese, zinc, copper, potassium and calcium.

[0011] In some embodiments of the present invention, the mass ratio of the manganese ore to the lignin is 5:(3-4); in some embodiments of the present invention, the mass ratio of the manganese ore to the lignin can be selected from any value of 5:3.0, 5:3.1, 5:3.2, 5:3.3, 5:3.4, 5:3.5, 5:3.6, 5:3.7, 5:3.8, 5:3.9, 5:4.0 or a range formed by any two of them.

[0012] In some embodiments of the present invention, the modified manganese ore is manganese ore modified by alkali metal borohydride.

[0013] In some embodiments of the present invention, the mass ratio of the manganese ore to the alkali metal borohydride is 50:(0.5-1.5); in some embodiments of the present invention, the mass ratio of the manganese ore to the alkali metal borohydride is any one of 50:0.5, 50:0.6, 50:0.7, 50:0.8, 50:0.9, 50:1.0, 50:1.1, 50:1.2, 50:1.3, 50:1.4, 50:1.5 or a range formed by any two of them.

[0014] In some embodiments of the present invention, the specific surface area of ​​the manganese ore is 20 to 30 m 2 / g; In some embodiments of the present invention, the specific surface area of ​​the manganese ore is 20m 2 / g, 21m 2 / g, 22m 2 / g, 23m 2 / g, 24m 2 / g, 25m 2 / g, 26m 2 / g, 27m 2 / g, 28m 2 / g, 29m 2 / g, 30m 2 / g, or a range of values ​​formed by any two of them.

[0015] In some embodiments of the present invention, the manganese ore has a porous structure.

[0016] In some embodiments of the present invention, the pore volume of the manganese ore is 0.06-0.07 cm 3 / g; In some embodiments of the present invention, the pore volume of the manganese ore is 0.06cm 3 / g, 0.061cm 3 / g, 0.062cm 3 / g, 0.063cm 3 / g, 0.064cm 3 / g, 0.065cm 3 / g, 0.066cm 3 / g, 0.067cm 3 / g, 0.068cm 3 / g, 0.069cm 3 / g, 0.07cm 3 / g, or a range of values ​​formed by any two of them.

[0017] In some embodiments of the present invention, the average pore diameter of the manganese ore is 10-15 nm; in some embodiments of the present invention, the average pore diameter of the manganese ore is any value of 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm or a range formed by any two of them.

[0018] In some embodiments of the present invention, the manganese ore comprises flaky manganese ore.

[0019] In some embodiments of the present invention, the manganese ore is natural manganese ore.

[0020] The second aspect of the present invention provides a method for preparing the slow-release fertilizer according to the first aspect of the present invention, comprising the following steps:

[0021] Manganese ore is sequentially mixed with alkali metal borohydride, metal salt and lignin to react and obtain the slow-release fertilizer.

[0022] In some embodiments of the present invention, the mixing reaction is carried out using an oscillator.

[0023] In some embodiments of the present invention, the mixing reaction time is 1 to 24 h; in some embodiments of the present invention, the mixing reaction time is 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 21 h, 22 h, 23 h, 24 h, any one of the values ​​or a range formed by any two of them.

[0024] In some embodiments of the present invention, the temperature of the mixed reaction is 20-40°C; in some embodiments of the present invention, the temperature of the mixed reaction is 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, any one of the values ​​or a range formed by any two of them.

[0025] In some embodiments of the present invention, the metal salt includes at least one of potassium salt, iron salt, calcium salt, copper salt, and zinc salt.

[0026] The third aspect of the present invention provides use of the slow-release fertilizer described in the first aspect of the present invention in the field of fertilizers.

[0027] The beneficial effects of the present invention are as follows: the present invention prepares a fertilizer that loads nutrients and can slowly release nutrients into the soil by loading nutrients onto manganese ore, and the fertilizer can be applied to the soil to significantly increase the content of nutrients (including manganese, potassium, iron, calcium, copper, and zinc) in the soil, specifically: manganese, zinc, and copper in the soil can be increased from 0 mg / L to 7.93-121.9 mg / L, 0.02-0.70 mg / L, and 0.00-0.66 mg / L, respectively, while the concentrations of iron, potassium, and calcium in the soil are increased by 122.8 times, 10.73 times, and 5.32 times, respectively. In addition, the slow-release fertilizer in the present invention is safe, green, and will not have an adverse effect on the environment, can simultaneously meet the supply and slow release of multiple nutrients, has universality and high efficiency, and can meet the needs of different elements or multi-element deficient soils.

[0028] The preparation method of the present invention is to use manganese ore as a base, and sequentially undergo modification treatments with alkali metal borohydride, metal salt, and lignin to prepare a slow-release fertilizer that can increase the release of soil nutrients and release them slowly. The preparation method is simple and easy to operate, the raw materials are widely available and inexpensive, the preparation conditions are mild, and it is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the XRD diffraction pattern of the natural manganese ore in Example 1.

[0030] Figure 2 This is a scanning electron microscope image of the natural manganese ore in Example 1.

[0031] Figure 3 This is the nitrogen adsorption curve of the natural manganese ore in Example 1.

[0032] Figure 4 This is the particle size distribution diagram of the natural manganese ore in Example 1.

[0033] Figure 5 This is a flow chart of the preparation process of the natural manganese ore in Example 6. DETAILED DESCRIPTION

[0034] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. The reagents or instruments used that do not indicate the manufacturer are all conventional products that can be purchased commercially.

[0035] Example 1

[0036] This example provides a method for preparing a supported manganese ore slow-release fertilizer, which specifically comprises the following steps:

[0037] S1. Pretreatment and characterization of natural manganese ore:

[0038] The natural manganese ore used in this example was collected from Leiyang, Hunan. Three natural manganese ore samples were collected, which were recorded as: natural manganese ore 1, natural manganese ore 2, and natural manganese ore 3; they were removed from the impurities, washed with water, ground, and then passed through a 100-mesh sieve. The elemental composition of the three natural manganese ores was analyzed by X-ray fluorescence spectroscopy, as shown in Table 1 below.

[0039] Table 1 Mass fraction of each element contained in three natural manganese ores

[0040] O Mn Fe Si Al K Ca Natural manganese ore1 42.55％ 15.24％ 13.56％ 20.64％ 5.04％ 0.40％ 0.12％ Natural manganese ore 2 41.05％ 21.26％ 16.01％ 17.31％ 2.45％ 0.39％ 0.19％ Natural manganese ore 3 40.43％ 23.32％ 16.14％ 15.87％ 2.28％ 0.41％ 0.20％

[0041] As can be seen from Table 1, the three natural manganese ores all contain high contents of manganese and iron, but the contents of manganese and iron in natural manganese ore 3 are significantly higher than those of the other two natural manganese ores (i.e., natural manganese ore 1 and natural manganese ore 2). The present invention mainly utilizes the slow dissolution of the two transition metal elements of iron and manganese in natural minerals during reduction in the soil, thereby releasing the elements and their complex elements in the minerals. Therefore, this example and the following embodiments all select the natural manganese ore 3 with a higher content of iron and manganese minerals, and the contents of potassium and calcium in the natural manganese ore 3 are also relatively high. The natural manganese ores recorded in the following embodiments all refer to the natural manganese ore 3.

[0042] Then, X-ray diffraction spectroscopy was used to identify the phase composition of natural manganese ore. The specific test diagram is as follows: Figure 1 As shown. Figure 1 It can be seen that the natural manganese ore used in this example is composed of quartz, goethite, calanite, and lithium pyrolusite. The surface morphology of the natural manganese ore was tested by scanning electron microscopy. Figure 2 As shown, Figure 2 (a) and Figure 2 (b) in the figure are SEM images of natural manganese ore at a scale of 1 μm and 200 nm respectively. Figure 2 It can be seen that natural manganese ore mainly has two forms: flake and needle. The flake form is quartz, calansite and pyrolusite, and the needle form is goethite.

[0043] The nitrogen adsorption and desorption curve, pore size, etc. of natural manganese ore were tested using a fully automatic specific surface area and porosity analyzer (BET). Figure 3 and Figure 4 As shown. Figure 3 and Figure 4 It can be seen that the specific surface area of ​​natural manganese ore is 24.0m 2 / g, the average pore volume is 0.064cm 3 / g, the average pore diameter is 11.07nm, and the manganese ore used has a large specific surface area and abundant pore sizes.

[0044] S2: Preparation of potassium-loaded natural manganese ore:

[0045] 500 mg of natural manganese ore was added to 40 mL of potassium borohydride solution with a concentration of 1.25 mol / L, 2.5 mol / L, and 5 mol / L, respectively, and filtered and washed after shaking on an oscillator for 3 hours, and dried to obtain manganese ore 1, manganese ore 2, and manganese ore 3, respectively. 40 mL of potassium chloride solution with a concentration of 0.1 mol / L was added to natural manganese ore, manganese ore 1, manganese ore 2, and manganese ore 3, respectively, and shaken on an oscillator for 10 hours again, filtered and washed, and dried to obtain potassium-based manganese ore 1 (not treated with potassium borohydride), potassium-based manganese ore 2, potassium-based manganese ore 3, and potassium-based manganese ore 4, respectively.

[0046] The effects of various manganese ores on the content of manganese, potassium, iron and calcium in flooded rice soil were tested. The specific test methods are as follows:

[0047] Paddy soil samples from Zhishan, Jiangmen were collected, ground through a 60-mesh sieve after impurities were removed, added to a 20 mL glass bottle, and 15 mL of water was added to make the soil flooded. Subsequently, natural manganese ore, potassium-based manganese ore 1, potassium-based manganese ore 2, potassium-based manganese ore 3, and potassium-based manganese ore 4, accounting for 5% of the mass of the paddy soil sample, were added to the paddy soil sample, oscillated on an oscillator for 5 minutes to ensure uniform mixing, and the culture experiment was carried out at 25 ° C. On the 3rd, 6th, and 9th days of the experiment, the soil suspension was filtered through a 0.22 μm filter head, and the manganese, iron, and potassium contents in the suspension were determined to evaluate the effects of the above-mentioned various manganese ores on the content of manganese, potassium, and iron nutrients in the soil. Blank flooded paddy soil was used as a control in the experiment, and the specific test results are shown in Table 2 below.

[0048] Table 2 Test results of the effects of various manganese ores on the content of nutrient elements in flooded rice soil

[0049]

[0050] As shown in Table 2, compared with natural manganese ore, loading potassium on natural manganese ore (using potassium borohydride or not) did not significantly increase the manganese, iron and calcium contents in the soil. After 9 days of application to the soil, the contents of manganese, iron and calcium in the soil were 0.00 mg / L, 0.15-0.17 mg / L and 6.29-8.04 mg / L, respectively. The potassium contents of the original soil were 1.45±0.00 mg / L, 1.65±0.01 mg / L and 1.73±0.01 mg / L at 3d, 6d and 9d of incubation, respectively. After adding natural manganese ore for 3d, 6d and 9d of incubation, the potassium contents were 1.68±0.03 mg / L, 1.72±0.37 mg / L and 1.74±0.04 mg / L, respectively. Therefore, directly applying natural manganese ore to the soil did not change the potassium content in the soil. Potassium-based manganese ore 1 obtained by exchanging potassium ions with natural manganese ore was applied to the soil. After 3d, 6d and 9d of cultivation, the potassium content was 2.05±0.00mg / L, 2.19±0.03mg / L and 2.55±0.11mg / L, respectively. Compared with the direct application of natural manganese ore, the release of potassium content was improved to a certain extent. The natural manganese ore was treated with 1.25mol / L, 2.5mol / L and 5mol / L potassium borohydride solution to obtain manganese ore 1, manganese ore 2 and manganese ore 3, which were then exchanged with potassium ions to obtain potassium-based manganese ore 2, potassium-based manganese ore 3 and potassium-based manganese ore 4. Potassium-based manganese ore 2, potassium-based manganese ore 3 and potassium-based manganese ore 4 were applied to the soil. After 9d of cultivation, the potassium content was 2.85±0.08mg / L, 2.96±0.03mg / L and 3.31±0.15mg / L, respectively, and the potassium content in the soil was significantly improved. Potassium borohydride treatment can significantly improve the effect of potassium-based manganese ore on the potassium content in the soil. When potassium borohydride reacts with natural manganese ore, its strong reducing property will destroy the crystal structure of natural manganese ore and produce more defect structures. These defect structures increase the specific surface area and active sites of natural manganese ore, which is conducive to the adsorption and fixation of potassium ions. Therefore, the higher the dosage of potassium borohydride, the more defect structures are produced, the stronger the adsorption capacity for potassium ions, and the more obvious the effect of increasing the potassium content in the soil.

[0051] S3. Preparation of loaded manganese ore slow-release fertilizer:

[0052] Potassium-based manganese ore 4 was mixed with 75 mg and 375 mg of lignin, respectively, to obtain potassium-based manganese ore-lignin 1 and potassium-based manganese ore-lignin 2, i.e., loaded manganese ore slow-release fertilizers.

[0053] Potassium-based manganese ore-lignin 1 and potassium-based manganese ore-lignin 2 were added to rice soil samples, respectively. The soil suspension was filtered through a 0.22 μm filter on the 3rd, 6th and 9th days of the experiment to evaluate the effect of lignin on potassium-based manganese ore 4 in increasing the content of manganese, potassium, iron and calcium nutrients in the soil. The specific test results are shown in Table 3 below.

[0054] Table 3 Test results of the effect of lignin addition on potassium-based manganese ore 4 in improving the nutrients in the soil

[0055]

[0056] As shown in Table 3, by adding lignin to potassium-based manganese ore 4, the release of nutrients (including manganese, iron, potassium and calcium) in the soil can be significantly increased. The specific analysis is as follows: By comparing potassium-based manganese ore-lignin 1 and potassium-based manganese ore-lignin 2, it can be seen that the application of lignin effectively improves the release of manganese, and the greater the amount of lignin applied, the higher the amount of manganese released. The content of other iron, potassium and calcium elements also increased significantly. Compared with the original rice soil, after the application of potassium-based manganese ore-lignin 2, the content of potassium, iron and calcium in the soil increased by 9.86-10.73, 34.80-75.13 and 4.66-5.03 times, respectively.

[0057] In the present invention, the organic acids and phenolic compounds produced by the decomposition of lignin can be used by microorganisms in the soil as carbon sources and electron donors to promote the growth and metabolism of microorganisms. Microorganisms (such as sulfate-reducing bacteria, iron-reducing bacteria, etc.) reduce the high-valent metal ions in the soil to low-valent states through respiration. At the same time, lignin can directly participate in the reduction and dissolution process of potassium-based manganese ore as a reducing agent. The present invention promotes the reduction and dissolution of manganese and iron in potassium-based manganese ore and the destruction of the structure by adding lignin to potassium-based manganese ore, and releases nutrients such as potassium and calcium. And potassium-based manganese ore also undergoes obvious reduction and dissolution under the action of lignin, releasing the nutrients of potassium-based manganese ore itself and its surface load, and the relevant mechanism is as follows:

[0058] Natural manganese ore (K, Mn, Fe, Ca) + lignin + soil → K, Mn, Fe, Ca (K + , Ca 2+ , Fe 3+ 、Zn 2+ , Cu 2+ ) Loaded manganese ore + lignin + soil → Mn, Fe, K + , Ca 2+ , Fe 3+ 、Zn 2+ , Cu 2+

[0059] Example 2

[0060] This example provides a method for preparing a supported manganese ore slow-release fertilizer, which specifically comprises the following steps:

[0061] S1. Pretreatment of natural manganese ore:

[0062] The natural manganese ore used in this example was mined from Leiyang, Hunan, and was sieved through a 100-mesh sieve after being cleaned, washed, and ground.

[0063] S2: Preparation of calcium-loaded natural manganese ore:

[0064] 500 mg of natural manganese ore was added to 40 mL of 5 mol / L potassium borohydride solution, and the mixture was shaken on an oscillator for 3 h, filtered and washed, and then added to 40 mL of 0.1 mol / L calcium chloride solution. The mixture was shaken on an oscillator for 10 h, filtered and washed, and dried to obtain calcium-loaded manganese ore, i.e., calcium-based manganese ore.

[0065] S3: Preparation of loaded manganese ore slow-release fertilizer:

[0066] The obtained calcium-based manganese ore was mixed with 375 mg of lignin to prepare the loaded manganese ore slow-release fertilizer in this example.

[0067] The loaded manganese ore slow-release fertilizer in this example was added to flooded rice soil, and then a cultivation experiment was carried out. The soil suspension was filtered through a 0.22 μm filter on the 3rd, 6th and 9th days to evaluate the effect of the calcium-based manganese ore on the content of manganese, potassium, iron and calcium nutrients. The specific test results are shown in Table 4.

[0068] Table 4 Test results of this example on the effect of increasing calcium in soil

[0069]

[0070] As can be seen from Table 4, this example not only significantly increased the calcium content in the soil by loading calcium into the natural manganese ore, but also significantly increased the contents of iron, potassium and manganese in the soil. Compared with the blank rice soil, the slow-release fertilizer in this example increased the calcium content in the soil by more than 4 times.

[0071] Example 3

[0072] This example provides a method for preparing a supported manganese ore slow-release fertilizer, which specifically comprises the following steps:

[0073] S1. Pretreatment of natural manganese ore:

[0074] The natural manganese ore used in this example was mined from Leiyang, Hunan, and was sieved through a 100-mesh sieve after being cleaned, washed, and ground.

[0075] S2: Preparation of zinc-loaded natural manganese ore:

[0076] 500 mg of manganese ore was added to 40 mL of 5 mol / L potassium borohydride solution, shaken on an oscillator for 3 h, filtered and washed, then added to 40 mL of 0.1 mol / L zinc chloride solution, shaken on an oscillator again for 10 h, filtered and washed, and dried to obtain zinc-loaded manganese ore.

[0077] S3: Preparation of loaded manganese ore slow-release fertilizer:

[0078] The obtained zinc-loaded manganese ore was mixed with 375 mg of lignin to prepare the loaded manganese ore slow-release fertilizer in this example.

[0079] The loaded manganese ore slow-release fertilizer in this example was added to the flooded rice soil, and then a cultivation experiment was carried out. The soil suspension was filtered through a 0.22 μm filter on the 3rd, 6th and 9th days to evaluate the effect of the loaded manganese ore slow-release fertilizer on the content of manganese, potassium, iron, calcium and zinc nutrients. The specific test results are shown in Table 5.

[0080] Table 5 Test results of this example on the effect of increasing zinc in soil

[0081]

[0082] As shown in Table 5, in this example, by loading zinc into natural manganese ore, the contents of calcium, manganese, potassium, zinc and iron in the soil can be significantly increased. However, no zinc was detected in the blank soil during the incubation process. Therefore, in this example, loading zinc into natural manganese ore can significantly increase the zinc content in the soil solution.

[0083] Example 4

[0084] This example provides a method for preparing a supported manganese ore slow-release fertilizer, which specifically comprises the following steps:

[0085] S1. Pretreatment of natural manganese ore:

[0086] The natural manganese ore used in this example was mined from Leiyang, Hunan, and was sieved through a 100-mesh sieve after being cleaned, washed, and ground.

[0087] S2: Preparation of copper-loaded natural manganese ore:

[0088] 500 mg of manganese ore was added to 40 mL of 5 mol / L potassium borohydride solution, shaken on an oscillator for 3 hours, filtered and washed, then added to 40 mL of 0.1 mol / L copper chloride solution, shaken on an oscillator again for 10 hours, filtered and washed, and dried to obtain copper-loaded manganese ore.

[0089] S3: Preparation of loaded manganese ore slow-release fertilizer:

[0090] The copper-loaded manganese ore obtained was mixed with 375 mg of lignin to prepare the loaded manganese ore slow-release fertilizer in this example.

[0091] The loaded manganese ore slow-release fertilizer in this example was added to the flooded rice soil, and then a cultivation experiment was carried out. The soil suspension was filtered through a 0.22 μm filter on the 3rd, 6th and 9th days to evaluate the effect of the loaded manganese ore slow-release fertilizer on the content of manganese, potassium, iron, calcium and copper nutrients. The specific test results are shown in Table 6.

[0092] Table 6 Test results of this example on the effect of increasing copper in soil

[0093]

[0094] As shown in Table 6, in this example, by loading copper into natural manganese ore, the contents of calcium, manganese, potassium, copper and iron in the soil can be significantly increased. However, no copper was detected in the blank soil during the incubation process. Therefore, in this example, loading copper into natural manganese ore can significantly increase the copper content in the soil solution.

[0095] Example 5

[0096] This example provides a method for preparing a supported manganese ore slow-release fertilizer, which specifically comprises the following steps:

[0097] S1. Pretreatment of natural manganese ore:

[0098] The natural manganese ore used in this example was mined from Leiyang, Hunan, and was sieved through a 100-mesh sieve after being cleaned, washed, and ground.

[0099] S2: Preparation of iron-loaded natural manganese ore:

[0100] 500 mg of manganese ore was added to 40 mL of 5 mol / L potassium borohydride solution, shaken on an oscillator for 3 h, filtered and washed, then added to 40 mL of 0.1 mol / L ferric chloride solution, shaken on an oscillator again for 10 h, filtered and washed, and dried to obtain iron-loaded manganese ore.

[0101] S3: Preparation of loaded manganese ore slow-release fertilizer:

[0102] The obtained iron-loaded manganese ore was mixed with 375 mg of lignin to prepare the loaded manganese ore slow-release fertilizer in this example.

[0103] The loaded manganese ore slow-release fertilizer in this example was added to the flooded rice soil, and then a cultivation experiment was carried out. The soil suspension was filtered through a 0.22 μm filter on the 3rd, 6th and 9th days to evaluate the effect of the loaded manganese ore slow-release fertilizer on the content of manganese, potassium, iron and calcium nutrients. The specific test results are shown in Table 7.

[0104] Table 7 Test results of this example on the effect of increasing iron in soil

[0105]

[0106] As shown in Table 7, this example can significantly increase the content of calcium, manganese, potassium and iron in the soil by loading iron in natural manganese ore. Compared with the blank paddy soil, the iron content in the soil after applying the slow-release fertilizer in this example increased by 46.1 to 122.8 times, which is also significantly higher than the iron content in the soil after the slow-release fertilizer in other embodiments.

[0107] Example 6

[0108] This example provides a method for preparing a supported manganese ore slow-release fertilizer, which specifically comprises the following steps:

[0109] S1. Pretreatment of natural manganese ore:

[0110] The natural manganese ore used in this example was mined from Leiyang, Hunan, and was sieved through a 100-mesh sieve after being cleaned, washed, and ground.

[0111] S2: Preparation of natural manganese ore loaded with multi-nutrient elements:

[0112] 500 mg of manganese ore was added to 40 mL of 5 mol / L potassium borohydride solution, shaken on an oscillator for 3 hours, filtered and washed, and then added to 40 mL of a mixed solution (containing 0.1 mol / L calcium chloride, 0.1 mol / L zinc chloride, 0.1 mol / L copper chloride and 0.1 mol / L ferric chloride), shaken on an oscillator again for 10 hours, filtered and washed, and dried to obtain multi-element loaded manganese ore.

[0113] S3: Preparation of loaded manganese ore slow-release fertilizer:

[0114] The obtained multi-element loaded manganese ore was mixed with 375 mg of lignin to prepare the loaded manganese ore slow-release fertilizer in this example.

[0115] The preparation process flow chart of the loaded manganese ore slow-release fertilizer in this example is as follows Figure 5 shown.

[0116] The loaded manganese ore slow-release fertilizer in this example was added to the flooded rice soil, and then a cultivation experiment was carried out. The soil suspension was filtered through a 0.22 μm filter on the 3rd, 6th and 9th days to evaluate the effect of the loaded manganese ore slow-release fertilizer on the content of manganese, potassium, iron, calcium, zinc and copper nutrients. The specific test results are shown in Table 8.

[0117] Table 8 Test results of this example on the improvement effect of various nutrients in the soil

[0118]

[0119] As can be seen from Table 8, in this example, multiple nutrients are used to load natural manganese ore, which is then mixed with lignin, so that when the obtained manganese ore loaded with multiple nutrients is applied to the soil, the content of various nutrients (including manganese, potassium, iron, calcium, zinc, copper, etc.) in the soil can be significantly increased, further indicating that the natural manganese ore in the present invention can be used as a carrier to load multiple nutrients, thereby serving as a slow-release fertilizer, thereby enhancing the content of nutrients in the soil and achieving a slow-release effect.

[0120] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A slow-release fertilizer, characterized in that: The invention comprises modified manganese ore, nutrient elements and lignin; the nutrient elements are loaded in the modified manganese ore.

2. The slow-release fertilizer according to claim 1, characterized in that: The nutrient elements include at least one of iron, manganese, zinc, copper, potassium and calcium.

3. The slow-release fertilizer according to claim 1, characterized in that: The mass ratio of the manganese ore to the lignin is 5:(3-4).

4. The slow-release fertilizer according to claim 1, characterized in that: The modified manganese ore is manganese ore modified by alkali metal borohydride.

5. The slow-release fertilizer according to claim 4, characterized in that: The mass ratio of the manganese ore to the alkali metal borohydride is 50:(0.5-1.5).

6. The slow-release fertilizer according to claim 4, characterized in that: The manganese ore has at least one of the following characteristics: (a) The specific surface area of ​​the manganese ore is 20 to 30 m 2 / g; (b) the manganese ore has a porous structure; (c) The pore volume of the manganese ore is 0.06 to 0.07 cm 3 / g; (d) the average pore diameter of the manganese ore is 10 to 15 nm; (e) The manganese ore comprises flake manganese ore.

7. The method for preparing the slow-release fertilizer according to any one of claims 1 to 6, characterized in that: The following steps are involved: Manganese ore is sequentially mixed with alkali metal borohydride, metal salt and lignin to react and obtain the slow-release fertilizer.

8. The method for preparing a slow-release fertilizer according to claim 7, characterized in that: The mixing reaction is carried out by using an oscillator; And / or, the mixing reaction time is 1 to 24 hours.

9. The method for preparing a slow-release fertilizer according to claim 7, characterized in that: The metal salt includes at least one of potassium salt, iron salt, calcium salt, copper salt and zinc salt.

10. Use of the slow-release fertilizer according to any one of claims 1 to 6 in the field of fertilizers.

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