A kind of agricultural fiber containing iron and manganese and preparation method thereof

Abstract

The invention provides an iron-manganese-containing agricultural fiber, which comprises the following components by mass fraction: 50-73% SiO2, 0-8% MgO, 20-31% CaO, Al2O3<3%, Fe2O30.02-6%, 0.02-2% MnO, 0.02-2% Na2O, 0.03-3% K2O; the ratio of (SiO2+Al2O3+Fe2O3+MnO) / (CaO+MgO+Na2O+K2O) is 1.8-3.2; and the molar ratio of O to Si in the agricultural fiber is 2.2-3.0. The present invention introduces Fe2O3 and MnO into the fiber, thereby increasing the defects of the fiber surface of the melt in the fiber-forming process without affecting the fiber-forming quality, and at the same time promoting the effective dissolution of the fiber in the soil, increasing the effective silicon, effective calcium and effective magnesium, effective iron and effective manganese content in the soil, and improving the root absorption capacity of plants or crops, thereby improving the yield and quality of the crops.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural fibers, and in particular relates to an agricultural fiber containing iron and manganese and a preparation method thereof. Background Art

[0002] The inorganic fibers currently used in agriculture are only used as base materials, without considering the harmful effects of the fibers themselves on the soil and the role of promoting plant absorption and growth. At the same time, the production of existing inorganic fibers only considers the temperature resistance and practicality in the industrial field, without considering the cost and environmental solubility. The melting temperature is high and the cost is increased.

[0003] At the same time, in the prior art, products that use inorganic fiber materials as culture media all require the addition of substances such as organic adhesives / binders. These organic adhesives / binders contain toxic substances such as phenol and formaldehyde that are harmful to the soil, causing lasting damage to the soil. Moreover, these organic adhesives / binders will be further absorbed by plants and may then be absorbed by the human body, causing permanent damage to the human body. Summary of the invention

[0004] In view of this, the object of the present invention is to provide an iron-manganese-containing agricultural fiber and a preparation method thereof. During the preparation process of the agricultural fiber, no organic adhesives / binders and other substances are used, and the agricultural fiber will not be further absorbed by plants due to the presence of organic adhesives / binders, thereby not causing harm to the human body.

[0005] The present invention provides an iron-manganese-containing agricultural fiber, which comprises the following components by mass fraction:

[0006] 50~73%SiO2, 0~8%MgO, 20~31%CaO, Al2O3<3%, 0.02 <Fe2O3≤6%,0.02~2%MnO,0.02~2%Na2O,0.03~3%K2O;

[0007] The ratio of (SiO2+Al2O3+Fe2O3+MnO) / (CaO+MgO+Na2O+K2O) is 1.8 to 3.2;

[0008] The molar ratio of O to Si in the agricultural fiber is 2.2 to 3.0.

[0009] In the present invention, the total mass content of SiO2, Al2O3, Fe2O3 and MnO is 1.8 to 3.2 with respect to the total mass content of CaO, MgO, Na2O and K2O, preferably 1.8 to 2.8. By controlling within the above range, the amount of acidic oxides and alkaline oxides can be controlled so that the pH value of the fiber after fiberization is between 5.6 and 7.4, satisfying the condition that the fiber after fiberization remains neutral to slightly acidic. Increasing the acidity of the fiber itself is the key to supplementing iron and manganese, so that plants or crops can effectively absorb iron or manganese elements.

[0010] In the present invention, the fiber contains 58-72% SiO2, 2-6% MgO, 22-29% CaO, Al2O3<1%, 0.05-1.5% Na2O, and 0.04-1.3% K2O;

[0011] In the present invention, 1≤Fe2O3≤4%, 0.5≤MnO≤1.5%, and the ratio of (SiO2+Al2O3+Fe2O3+MnO) / (CaO+MgO+Na2O+K2O) is preferably 1.8-2.8.

[0012] In the present invention, the molar ratio of O to Si in the agricultural fiber is 2.2 to 3.0, preferably 2.4 to 2.8; within this range, the fiber quality during the fiber-forming process can be controlled and the diameter stability of the fiber during the fiber-forming process can be improved. If the O / Si molar ratio is too high, fiber formation is impossible; if the O / Si molar ratio is too low, the fiber diameter (>4 μm) is too large and cannot meet the actual application requirements of agriculture.

[0013] The agricultural fibers have a diameter of 1 to 2 μm accounting for 10 to 30 wt%, 2 to 3 μm accounting for 60 to 80 wt%, 3 to 4 μm accounting for 10 to 20 wt%, and 4 to 5 μm accounting for 1 to 5 wt%. If the fiber diameter of 4 to 5 μm accounts for a large proportion, the bulk density of the fiber product is too large, the air permeability is poor, and the water absorption rate is reduced.

[0014] In the present invention, the contents of effective silicon, effective calcium, effective magnesium, effective iron and effective manganese in the agricultural fiber are 20-500 mg / kg, 10-200 mg / kg, 3-100 mg / kg, 10-80 mg / kg and 3-40 mg / kg respectively. In the present invention, the test method for effective silicon is "NY / T 1121.15-2006 Soil Testing Series Standards"; the test method for effective calcium and magnesium is "LY / T 2445-2015 Technical Specifications for Topsoil Protection for Greening"; the test method for effective iron and effective manganese is based on "NY / T 890-2004 Determination of the Content of Effective Zinc, Manganese, Iron and Copper in Soil".

[0015] In the present invention, the pH value of the agricultural fiber is 5.6-7.4; the pH value in this range is conducive to the absorption of effective elements by plants.

[0016] The thermal conductivity of the agricultural fiber at an average temperature of 25°C is 0.03 to 0.06 W / mK. The specific surface area of ​​the agricultural fiber is 400 to 700 m 2 / kg, increasing the contact area between fiber, plants and soil.

[0017] In the present invention, the bulk density of the agricultural fiber is 48 to 160 kg / m 3 ; Need to reach 48kg / m 3 To maintain the water and fertilizer needs of plant-level crops; if the bulk density is too low, it is not conducive to water retention and the ability to provide support for plant growth.

[0018] In the present invention, the porosity of the agricultural fiber is 50-90%; it has a porous property so as to provide sufficient water and air for the germination and root growth of plants in the growth medium.

[0019] In the present invention, the water retention rate of the agricultural fiber is 100-1000%, and the agricultural fiber should have good water retention capacity. After the agricultural fiber fully absorbs water, it is weighed and then dried in an oven at 105±2℃. By measuring the weight change before and after drying, the reduced mass is the water retention amount, which can be used as an indicator of soil water retention. Agricultural fiber has good water retention, fertilizer retention and air permeability.

[0020] The present invention introduces Fe2O3 and MnO into the fiber, which can increase the defects of the fiber surface during the fiber forming process without affecting the fiber quality (see Figure 2 , SEM of fiber surface), and at the same time promote the effective dissolution of fiber in soil, increase the effective silicon, effective calcium and effective magnesium, effective iron and effective manganese content in the soil, and improve the root absorption capacity of plants or crops, thereby improving the yield and quality of crops.

[0021] The present invention provides a method for preparing the iron-manganese-containing agricultural fiber described in the above technical solution, comprising the following steps:

[0022] The calcium stone powder, silica powder, magnesia, iron-containing materials and manganese-containing materials are mixed and melted, spun or blown into fibers, and heat-treated to obtain iron-manganese-containing agricultural fibers.

[0023] In the present invention, the melting temperature is 1400-1800° C., and the fiber forming temperature is 1400-1600° C. The introduction of Fe2O3 and MnO in the preparation process can reduce the melting temperature of the raw material by 1800-2000° C., so that it can be melted at 1400-1800° C.

[0024] In the present invention, the calcium stone powder is selected from one or more of lime containing CaO, light-burned dolomite, heavy-burned dolomite, wollastonite and calcium-containing minerals;

[0025] The silica powder is selected from one or more of silica containing SiO2, quartz sand and silicon-containing minerals;

[0026] The magnesia is selected from one or more of fused magnesia containing MgO, light-burned magnesia, light-burned dolomite, heavy-burned dolomite, forsterite and magnesium-containing minerals;

[0027] The iron-containing material is selected from one or more of magnetite, hematite and iron-containing minerals;

[0028] The manganese-containing material is selected from one or more of manganese carbonate, manganese oxide and manganese-containing minerals.

[0029] In the present invention, the raw materials for preparation also preferably include aluminum-containing raw materials, potassium-containing raw materials and sodium-containing raw materials; the aluminum-containing raw materials may be one or more of industrial alumina, calcined alumina and aluminum-containing minerals;

[0030] The potassium-containing raw material is selected from one or more of potassium carbonate (K2CO3), potassium bicarbonate (KHCO3) and potassium-containing minerals;

[0031] The sodium-containing raw material may be one or more of sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3) and sodium-containing minerals.

[0032] In the present invention, the heat treatment temperature is 400-700° C. and the time is 5-10 minutes.

[0033] The above-mentioned natural ore used in the present invention is melted and then fiberized to accelerate the process from rock to soil. In addition, the structural defects that appear in the fiberization process accelerate the biological solubility of the fiber in the soil. The fiber will dissolve, peel and pulverize during use (see Figure 1 This is a SEM image of agricultural fiber containing iron and manganese elements; Figure 2 This is the SEM image of fiber defects that are not dissolved by water; Figure 3 The SEM image of the fiber surface after being dissolved in water) releases silicon, calcium, magnesium and other elements required for plant growth. During use, the fiber structure gradually changes, making the soil loose and breathable, which is conducive to the development of plant roots. At the same time, due to its biological solubility, it can also provide silicon, calcium, magnesium, iron, potassium, manganese and other elements required for the growth of different plants. The heavy metal index is not higher than the national standard (GB5085.3-2007 Identification Standard for Hazardous Waste Leaching Toxicity Identification). BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a SEM image of agricultural fiber containing iron and manganese elements;

[0035] Figure 2 is the SEM image of the fiber that was not dissolved by water;

[0036] Figure 3 This is the SEM image of the fiber surface after water dissolution. DETAILED DESCRIPTION

[0037] In order to further illustrate the present invention, an agricultural fiber containing iron and manganese and a preparation method thereof provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0038] Example 1

[0039] The required raw materials of calcium stone powder, silica powder, magnesia, magnetic powder and manganese oxide are uniformly mixed in a weight percentage of 28.5:64.2:4.8:1.5:1, continuously melted in the range of 1700-1850°C, and spun into fibers at a fiber forming temperature of 1570-1600°C, a spinning line speed of 170m / s, a heat treatment temperature of 560°C, and a time of 6 minutes to obtain iron-manganese-containing agricultural fibers.

[0040] The agricultural fiber obtained in this embodiment has SiO2: 64.5wt%; MgO: 4.99wt%; CaO: 29.22wt%; Al2O3: 0.645wt%; Fe2O3: 1.35wt%, MnO: 0.64wt%, Na2O: 0.1wt%, K2O: 0.23wt%, O / Si molar ratio: 2.65, (SiO2+Al2O3+Fe2O3+MnO) / (CaO+MgO+Na2O+K2O) weight: 1.94, bulk density is 64kg / cm 3 The average fiber diameter is 3.9 microns, fibers with a diameter of 1-2μm account for 23wt%, fibers with a diameter of 2-3μm account for 62wt%, fibers with a diameter of 3-4μm account for 12wt%, fibers with a diameter of 4-5μm account for 3wt%, the average thermal conductivity at 25°C is 0.037W / mk, the pH value is 7.24, the water absorption rate is 820%, the porosity is 85%, and cadmium, mercury, arsenic, lead, etc. do not exceed the standard.

[0041] The contents of effective silicon, effective calcium, effective magnesium, effective iron and effective manganese in the agricultural fiber are 480 mg / kg, 80 mg / kg, 30 mg / kg, 13 mg / kg and 5 mg / kg respectively.

[0042] Example 2

[0043] The required raw materials of calcium stone powder, silica powder, magnesia, magnet powder and manganese oxide are uniformly mixed according to the weight percentage of 23.8:70.3:2.5:1.6:1.8, continuously melted in the range of 1600-1750°C, and spun into fibers with a fiber forming temperature of 1570-1640°C, a spinning line speed of 170m / s, a heat treatment temperature of 580°C and a time of 5min to obtain agricultural fibers.

[0044] The agricultural fiber obtained in this embodiment has SiO2: 69.2wt%; MgO: 2.01wt%; CaO: 23.12wt%; Al2O3: 1.445wt%; Fe2O3: 1.18wt%, MnO: 1.04wt%, Na2O: 0.61wt%, K2O: 1.1wt%, O / Si molar ratio: 2.45, (SiO2+Al2O3+Fe2O3+MnO) / (CaO+MgO+Na2O+K2O) weight ratio: 2.68, and bulk density is 80kg / cm 3 The average fiber diameter is 3.4 microns, the fiber with a diameter of 1-2μm accounts for 19wt%, the fiber with a diameter of 2-3μm accounts for 70wt%, the fiber with a diameter of 3-4μm accounts for 8wt%, and the fiber with a diameter of 4-5μm accounts for 3wt%. The average thermal conductivity at 25°C is 0.032W / mk, the pH value is 7.15, the water absorption rate is 530%, the porosity is 80%, and the specific surface area is 580m 2 / kg, cadmium, mercury, arsenic, lead, etc. do not exceed the standard.

[0045] The contents of effective silicon, effective calcium, effective magnesium, effective iron and effective manganese in the agricultural fiber are 410 mg / kg, 60 mg / kg, 16 mg / kg, 12 mg / kg and 10 mg / kg respectively.

[0046] Comparative Example 1

[0047] The raw materials of calcium stone powder, silica powder, magnesia, magnetite powder and manganese oxide are uniformly mixed in a weight percentage of 29.8:64.3:4.6:1.3:0, continuously melted in the range of 1500-1650°C, and spun into fibers at a fiber forming temperature of 1410-1480°C, a spinning line speed of 170m / s, a heat treatment temperature of 620°C, and a time of 4min to obtain agricultural fibers.

[0048] The agricultural fiber obtained in this comparative example has SiO2: 62.5wt%; MgO: 3.99wt%; CaO: 29.22wt%; Al2O3: 0.515wt%; Fe2O3: 1.05wt%, MnO: 0%, Na2O: 0.2wt%, K2O: 1.51wt%, O / Si molar ratio: 2.67, (SiO2+Al2O3+Fe2O3+MnO) / (CaO+MgO+Na2O+K2O) weight ratio: 1.78, and bulk density is 96kg / cm 3 The average fiber diameter is 3.3 microns, the fiber with a diameter of 1-2μm accounts for 25wt%, the fiber with a diameter of 2-3μm accounts for 65wt%, the fiber with a diameter of 3-4μm accounts for 7wt%, and the fiber with a diameter of 4-5μm accounts for 3wt%. The average thermal conductivity at 25℃ is 0.033W / mk, the pH value is 7.44, the water absorption rate is 650%, the porosity is 75%, and the specific surface area is 500m 2 / kg, cadmium, mercury, arsenic, lead, etc. do not exceed the standard.

[0049] The contents of effective silicon, effective calcium, effective magnesium, effective iron and effective manganese in the agricultural fiber are 240 mg / kg; 18 mg / kg, 2 mg / kg, 6 mg / kg, 0 mg / kg respectively.

[0050] Comparative Example 2

[0051] The required raw materials of calcium stone powder, silica powder, magnesia, magnetite powder and manganese oxide are mixed evenly in a weight percentage of 28.7:62.8:5.5:1.8:1.2, and continuously melted at 1600-1750°C, and spun into fibers at a fiber forming temperature of 1570-1640°C, a spinning line speed of 180m / s, a heat treatment temperature of 490°C, and a time of 8min to obtain agricultural fibers.

[0052] The agricultural fiber obtained in this comparative example has SiO2: 61.3wt%; MgO: 5.11wt%; CaO: 27.12wt%; Al2O3: 0.22wt%; Fe2O3: 1.2wt%, MnO: 0.8wt%, Na2O: 1.41wt%, K2O: 2.1wt%, O / Si molar ratio: 2.67, (SiO2+Al2O3+Fe2O3+MnO) / (CaO+MgO+Na2O+K2O) weight: 1.78, and bulk density is 96kg / cm 3The average fiber diameter is 3.1 microns, the fiber with a diameter of 1-2μm accounts for 20wt%, the fiber with a diameter of 2-3μm accounts for 73wt%, the fiber with a diameter of 3-4μm accounts for 5wt%, and the fiber with a diameter of 4-5μm accounts for 2wt%. The average thermal conductivity at 25°C is 0.031W / mk, the pH value is 7.65, the water absorption rate is 630%, the porosity is 82%, and the specific surface area is 480m 2 / kg, cadmium, mercury, arsenic, lead, etc. do not exceed the standard.

[0053] The contents of effective silicon, effective calcium, effective magnesium, effective iron and effective manganese in the agricultural fiber are 180 mg / kg, 10 mg / kg, 4 mg / kg, 3 mg / kg and 0.9 mg / kg respectively.

[0054] Comparative Example 3

[0055] The required raw materials of calcium stone powder, silica powder, magnesia, industrial alumina, potassium carbonate, sodium carbonate, magnetic powder and manganese oxide are uniformly mixed in a weight percentage of 30:52.6:6.2:3.7:2.2:2.0:1.9:1.4, continuously melted in the range of 1600-1750°C, and spun into fibers with a fiber forming temperature of 1570-1640°C, a spinning line speed of 180m / s and a heat treatment temperature of 650°C to obtain agricultural fibers.

[0056] The agricultural fiber obtained in this comparative example has SiO2: 53.3wt%; MgO: 6.28wt%; CaO: 30.1wt%; Al2O3: 3.6wt%; Fe2O3: 1.68%, MnO: 1.2wt%, Na2O: 1.9wt%, K2O: 1.64wt%, O / Si molar ratio: 3.1, (SiO2+Al2O3+Fe2O3+MnO) / (CaO+MgO+Na2O+K2O) weight ratio: 1.51, and bulk density is 96kg / cm 3 The average fiber diameter is 2.6 microns, the fiber with a diameter of 1-2μm accounts for 25wt%, the fiber with a diameter of 2-3μm accounts for 73wt%, the fiber with a diameter of 3-4μm accounts for 2wt%, and the fiber with a diameter of 4-5μm accounts for 0wt%. The average thermal conductivity at 25℃ is 0.030W / mk, the pH value is 7.45, the water absorption rate is 530%, the porosity is 72%, and the specific surface area is 510m 2 / kg, cadmium, mercury, arsenic, lead, etc. do not exceed the standard.

[0057] The contents of effective silicon, effective calcium, effective magnesium, effective iron and effective manganese in the agricultural fiber are 160 mg / kg, 10 mg / kg, 3 mg / kg, 3 mg / kg and 0.9 mg / kg respectively.

[0058] It can be seen from the above embodiments that the present invention provides an iron-manganese-containing agricultural fiber, which includes the following components by mass fraction: 50-73% SiO2, 0-8% MgO, 20-31% CaO, Al2O3<3%, Fe2O30.02-6%, 0.02-2% MnO, 0.02-2% Na2O, 0.03-3% K2O; the ratio of (SiO2+Al2O3+Fe2O3+MnO) / (CaO+MgO+Na2O+K2O) is 1.8-3.2; the molar ratio of O and Si in the agricultural fiber is 2.2-3.0. The present invention introduces Fe2O3 and MnO into the fiber, thereby increasing the defects of the fiber surface of the melt in the fiber-forming process without affecting the fiber-forming quality, and at the same time promoting the effective dissolution of the fiber in the soil, increasing the effective silicon, effective calcium and effective magnesium, effective iron and effective manganese content in the soil, and improving the root absorption capacity of plants or crops, thereby improving the yield and quality of the crops.

[0059] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An agricultural fiber containing iron and manganese, comprising the following components by mass fraction: 50~73%SiO2, 0~8%MgO, 20~31%CaO, Al2O3<3%, Fe2O31~4%, 0.5~1.5%MnO, 0.02~2%Na2O, 0.03~3%K2O; The ratio of (SiO2+Al2O3+Fe2O3+MnO) / (CaO+MgO+Na2O+K2O) is 1.8~2.8; The molar ratio of O to Si in the agricultural fiber is 2.4 to 2.8; Among the agricultural fibers, fibers with a diameter of 1 to 2 μm account for 10 to 30 wt%, fibers with a diameter of 2 to 3 μm account for 60 to 80 wt%, fibers with a diameter of 3 to 4 μm account for 10 to 20 wt%, and fibers with a diameter of 4 to 5 μm account for 1 to 5 wt%; The contents of effective silicon, effective calcium, effective magnesium, effective iron and effective manganese in the agricultural fiber are 20-500 mg / kg, 10-200 mg / kg, 3-100 mg / kg, 10-80 mg / kg and 3-40 mg / kg respectively; The pH value of the agricultural fiber is 5.6-7.4; The thermal conductivity of the agricultural fiber at an average temperature of 25°C is 0.03-0.06 W / mK; The bulk density of the agricultural fiber is 48-160 kg / m 3 ; The specific surface area of ​​the agricultural fiber is 400-700m 2 / kg; porosity is 50~90%; water retention rate is 100~1000%.

2. A method for preparing the iron-manganese-containing agricultural fiber according to claim 1, comprising the following steps: The calcium stone powder, silica powder, magnesia, iron-containing materials and manganese-containing materials are mixed and melted, spun or blown into fibers, and heat-treated to obtain iron-manganese-containing agricultural fibers.

3. The preparation method according to claim 2, characterized in that: The melting temperature is 1400-1800°C, and the fiber forming temperature is 1400-1600°C.

4. The preparation method according to claim 2, characterized in that: The calcium stone powder is selected from one or more of lime containing CaO, light-burned dolomite, heavy-burned dolomite and wollastonite; The silica powder is selected from silica and / or quartz sand containing SiO2; The magnesia is selected from one or more of fused magnesia containing MgO, light-burned magnesia, light-burned dolomite, heavy-burned dolomite and forsterite; The iron-containing material is selected from magnetite and / or hematite; The manganese-containing material is selected from manganese carbonate and / or manganese oxide.

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