Activated magnetic mineral soil conditioner and preparation method of soilless culture base material

Abstract

The invention provides a preparation method of an activated magnetic mineral soil conditioner and a soilless culture base material, and belongs to the technical field of soil conditioners. Comprising the following steps: S1, performing magnetic separation to remove impurities by taking magnetic separation iron ore tailings after iron extraction and steel slag as raw materials; s2, the raw materials are placed in an electromagnetic rotary kiln to be activated, and iron mineral lattice reconstruction and harmful element passivation are achieved; s3, mixing the activated material with a binder, and granulating, wherein the particle size is controlled to be 0.5-3mm; s4, treating the granulated material in a pulsed magnetic field, screening out qualified particles, feeding the qualified particles into a packaging line to prepare an activated magnetic mineral soil conditioner, and feeding unqualified fine powder into a superfine grinding system; s5, the unqualified fine powder is prepared into a base material through airflow grinding for later use, the preparation method is simple, the raw material source is wide, the cost is low, the soil texture can be obviously improved, the content of heavy metal ions in soil can be obviously reduced, and the good growth promoting effect on crops is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil improvers, and particularly relates to an activated magnetic mineral soil improver and a preparation method of a soilless cultivation substrate. Background Art

[0002] With the rapid development of the global economy, the mining industry and its related industries are facing dual pressures such as resource depletion and environmental pollution. As a by-product of the mineral resource development process, iron ore tailings contain a large amount of mineral components, yet their resource utilization has not been fully emphasized. In recent years, the problem of soil pollution has become increasingly serious, and agricultural production is facing the challenge of declining soil quality. There is an urgent need to find effective soil improvement solutions. Therefore, using iron ore tailings as raw materials for making activated magnetic mineral special soil (soil improver) can not only realize the resource utilization of tailings, relieve environmental pressure, but also improve soil structure and enhance soil fertility, promoting the development of sustainable agriculture.

[0003] By resourcefully utilizing the magnetic separation iron ore tailings generated after iron extraction, the impact of tailings on the environment can be effectively reduced, and the potential safety hazards of tailings storage can be minimized. Secondly, the research and application of activated magnetic mineral special soil (soil improver) will provide new soil improvement materials for agriculture, enhance the physical and chemical properties of the soil, promote plant growth, and improve the yield and quality of crops. Finally, the implementation of the project will drive the innovation and development of related technologies, form an industrial chain, boost local economic growth, and improve resource utilization efficiency.

[0004] In the prior art, industrial solid wastes such as magnetic separation iron ore tailings and steel slag are mostly disposed of by landfill or simple crushing, which poses a risk of heavy metal pollution and has a low resource utilization rate (see the limitations of steel slag activation technology in patent CN202111498700.4). Traditional soil improvers mostly rely on non-renewable resources such as peat and vermiculite, and the existing magnetization treatment technologies (such as patent CN202221403981.0) have not solved the following problems:

[0005] 1. The synergistic effect of mineral lattice reconstruction and harmful element passivation has not been achieved;

[0006] 2. There is a lack of a hierarchical magnetization process for precise control of product performance. Summary of the Invention

[0007] The purpose of the present invention is to provide an activated magnetic mineral soil improver and a preparation method of a soilless cultivation substrate. The preparation method is simple, the raw materials are widely sourced, and the cost is relatively low. The prepared activated magnetic mineral soil improver can significantly improve soil quality and reduce the content of heavy metal ions in the soil, and the prepared soilless cultivation substrate has a good effect of promoting the growth of crops.

[0008] The technical solution of the present invention is realized as follows:

[0009] The present invention provides a preparation method of an activated magnetic mineral soil conditioner, comprising the following steps:

[0010] S1. Using the magnetic separation iron ore tailings and steel slag after iron extraction as raw materials, after magnetic separation to remove impurities, controlling the particle size Dv50 ≤ 5 mm;

[0011] S2. Placing the raw materials in an electromagnetic rotary kiln for activation to achieve the reconstruction of the iron mineral lattice and the passivation of harmful elements;

[0012] S3. Mixing the activated materials with a binder and granulating, controlling the particle size to be 0.5 - 3 mm;

[0013] S4. Treating the granulated materials in a pulsed magnetic field, screening out qualified particles to enter the packaging line to obtain the activated magnetic mineral soil conditioner, and the unqualified fine powder enters the ultrafine grinding system;

[0014] S5. Preparing the unqualified fine powder into a base material by a jet mill for later use.

[0015] As a further improvement of the present invention, in step S1, the TFe in the magnetic separation iron ore tailings after iron extraction is ≤ 8%, SiO2 ≥ 45%, and the TFe in the steel slag is ≤ 3%, SiO2 ≥ 35%.

[0016] As a further improvement of the present invention, in step S2, the magnetic field strength is 0.5 - 1.2 T, the temperature is 550 - 750 °C, and the activation time is 0.5 - 2 h.

[0017] As a further improvement of the present invention, in step S3, the binder is composed of at least two of bentonite, starch, organic fertilizer, and microbial inoculum, and the mass ratio of the activated materials to the binder is 60 - 70:20 - 40.

[0018] As a further improvement of the present invention, in step S3, the binder is prepared by mixing bentonite, starch, organic fertilizer, and microbial inoculum according to a mass ratio of 3 - 8:5 - 10:2 - 10:0.1 - 0.5.

[0019] As a further improvement of the present invention, in step S4, the intensity of the pulsed magnetic field is 0.8 - 2 T, the frequency is 20 - 80 Hz, the time is 3 - 8 min, the particle size of the qualified particles is 0.5 - 3 mm, and the particle size of the unqualified fine powder is < 0.5 mm.

[0020] As a further improvement of the present invention, in step S5, the D of the base material 90 ≤ 15 μm.

[0021] The present invention further protects the activated magnetic mineral soil conditioner prepared by the above preparation method.

[0022] The present invention further protects the base material prepared by the above-mentioned preparation method.

[0023] The present invention further protects a preparation method of a soilless cultivation base material, which comprises uniformly mixing the base material as described in claim 9, phosphate-solubilizing bacteria and humic acid according to a mass ratio of 90-95:0.1-0.5:2-5 to obtain the soilless cultivation base material.

[0024] The present invention has the following beneficial effects:

[0025] The activated magnetic mineral soil conditioner and the preparation method of the soilless cultivation base material prepared by the present invention are simple, have a wide range of raw material sources, and low costs. The prepared activated magnetic mineral soil conditioner can significantly improve the soil quality and reduce the content of heavy metal ions in the soil, and the prepared soilless cultivation base material has a good effect on promoting the growth of crops.

[0026] Process collaborative innovation: By means of electromagnetic activation (lattice reconstruction) + magnetization classification (performance regulation), the water retention rate of the substrate (≥45%) and the stability of the conductivity value (1.0-1.5 mS / cm) are improved in a dual effect;

[0027] Environmental safety: The leaching amount of heavy metals is lower than the limit value of GB / T 18599-2020, and there is no risk of secondary pollution;

[0028] Resource utilization degree: The comprehensive utilization rate ≥98%, which is more than 30% higher than the traditional process. Specific embodiments

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] Example 1

[0031] This example provides a preparation method of an activated magnetic mineral soil conditioner and a soilless cultivation base material, which comprises the following steps:

[0032] S1. Using the magnetic separation iron ore tailings after iron extraction (TFe 6.5%, SiO2 48%) and steel slag (TFe 2.8%, SiO2 38) as raw materials, after magnetic separation and impurity removal, controlling the particle size Dv50 ≤ 5 mm to ensure that the content of heavy metals and radioactive elements is lower than the standard limit value of GB 8172-87;

[0033] S2. Place the raw materials in an electromagnetic rotary kiln for activation. The magnetic field strength is 0.5 T, the temperature is 550 °C, and the activation time is 0.5 h to achieve the lattice reconstruction of iron minerals and passivation of harmful elements;

[0034] S3. Mix the activated materials with a binder and granulate them. The mass ratio of the activated materials to the binder is 60:20, and the particle size is controlled within 0.5 - 3 mm;

[0035] The binder is prepared by mixing bentonite, starch, organic fertilizer, and microbial inoculant in a mass ratio of 3:5:2:0.1;

[0036] S4. Treat the granulated materials in a pulsed magnetic field. The intensity of the pulsed magnetic field is 0.8 T, the frequency is 20 Hz, and the time is 3 min. Screen out the qualified particles (particle size 0.5 - 3 mm) and send them to the packaging line to produce the activated magnetic mineral soil conditioner. The unqualified fine powder (particle size < 0.5 mm) enters the ultrafine grinding system;

[0037] S5. Prepare the base material (D 90 ≤15 μm) from the unqualified fine powder by a jet mill, and mix it evenly with phosphate-solubilizing bacteria and humic acid in a mass ratio of 90:0.1:2 to produce the soilless cultivation base material.

[0038] Example 2

[0039] This example provides a method for preparing an activated magnetic mineral soil conditioner and a soilless cultivation base material, including the following steps:

[0040] S1. Use the magnetic separation iron ore tailings after iron extraction (TFe 6.5%, SiO2 48%) and steel slag (TFe 2.8%, SiO2 38) as raw materials. After magnetic separation for impurity removal, control the particle size Dv50 ≤ 5 mm to ensure that the heavy metal and radioactive element contents are lower than the standard limits of GB 8172 - 87;

[0041] S2. Place the raw materials in an electromagnetic rotary kiln for activation. The magnetic field strength is 1.2 T, the temperature is 750 °C, and the activation time is 2 h to achieve the lattice reconstruction of iron minerals and passivation of harmful elements;

[0042] S3. Mix the activated materials with a binder and granulate them. The mass ratio of the activated materials to the binder is 70:40, and the particle size is controlled within 0.5 - 3 mm;

[0043] The binder is prepared by mixing bentonite, starch, organic fertilizer, and microbial inoculant in a mass ratio of 8:10:10:0.5;

[0044] S4. The materials after granulation are treated in a pulsed magnetic field. The intensity of the pulsed magnetic field is 2 T, the frequency is 80 Hz, and the time is 8 min. Qualified particles (particle size 0.5 - 3 mm) are screened out and enter the packaging line to obtain the activated magnetic mineral soil conditioner. Unqualified fine powder (particle size < 0.5 mm) enters the ultrafine grinding system;

[0045] S5. The unqualified fine powder is prepared into a base material (D 90 ≤ 15 μm) by a jet mill and mixed evenly with phosphate-solubilizing bacteria and humic acid in a mass ratio of 95:0.5:5 to obtain the soilless cultivation base material.

[0046] Example 3

[0047] This example provides a preparation method for an activated magnetic mineral soil conditioner and a soilless cultivation base material, including the following steps:

[0048] S1. Using the magnetic separation iron ore tailings after iron extraction (TFe 6.5%, SiO2 48%) and steel slag (TFe 2.8%, SiO2 38) as raw materials, after magnetic separation and impurity removal, control the particle size Dv50 ≤ 5 mm to ensure that the heavy metal and radioactive element contents are lower than the standard limits of GB 8172 - 87;

[0049] S2. Place the raw materials in an electromagnetic rotary kiln for activation. The magnetic field intensity is 1 T, the temperature is 650 °C, and the activation time is 2 h to achieve the lattice reconstruction of iron minerals and the passivation of harmful elements;

[0050] S3. Mix the activated materials with a binder and granulate. The mass ratio of the activated materials to the binder is 65:30, and the particle size is controlled within 0.5 - 3 mm;

[0051] The binder is prepared by mixing bentonite, starch, organic fertilizer, and microbial inoculant in a mass ratio of 5:7:7:0.3;

[0052] S4. The materials after granulation are treated in a pulsed magnetic field. The intensity of the pulsed magnetic field is 1 T, the frequency is 50 Hz, and the time is 5 min. Qualified particles (particle size 0.5 - 3 mm) are screened out and enter the packaging line to obtain the activated magnetic mineral soil conditioner. Unqualified fine powder (particle size < 0.5 mm) enters the ultrafine grinding system;

[0053] S5. The unqualified fine powder is prepared into a base material (D 90 ≤ 15 μm) by a jet mill and mixed evenly with phosphate-solubilizing bacteria and humic acid in a mass ratio of 92:0.3:3 to obtain the soilless cultivation base material.

[0054] Test Example 1

[0055] 1. Test materials:

[0056] The test soil was collected from the farmland of Dabaoshan. Before the test, the soil samples were air-dried, passed through a 2-mm sieve, and plant roots, small stones and other impurities were removed.

[0057] Test objects: The multi-element soil conditioners of Examples 1-3 and Comparative Examples 1-3.

[0058] 2. Test method:

[0059] Each pot of sandy soil weighed 1500 g. 10 g of the activated magnetic mineral soil conditioner prepared in Examples 1-3 was mixed into each pot, and the same amount of sandy soil was mixed into the blank group. After mixing evenly, various indexes were measured. The results are shown in Table 1 and Table 2.

[0060] Table 1

[0061]

[0062] Table 2

[0063] Group Total water-stable aggregates (%) > 0.25 mm Porosity (%) Total bacteria (cfu / g) Example 1 54 49 <![CDATA[5.82×10 8 > Example 2 51 47 <![CDATA[5.22×10 8 > Example 3 50 50 <![CDATA[5.64×10 8 > Blank group 32 30 <![CDATA[2.11×10 5 >

[0064] As can be seen from the above table, the activated magnetic mineral soil conditioner prepared in Examples 1-3 of the present invention can significantly improve the soil texture.

[0065] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Preparation method of an activated magnetic mineral soil conditioner, characterized in that, Including the following steps: S1. Using the magnetic separation iron ore tailings and steel slag after iron extraction as raw materials, after magnetic separation to remove impurities, controlling the particle size Dv50 ≤ 5 mm; S2. Placing the raw materials in an electromagnetic rotary kiln for activation to achieve the lattice reconstruction of iron minerals and passivation of harmful elements; S3. Mixing the activated materials with a binder and then granulating, controlling the particle size to be 0.5 - 3 mm; S4. Treating the granulated materials in a pulsed magnetic field, screening out qualified particles to enter the packaging line to obtain an activated magnetic mineral soil conditioner, and the unqualified fine powder enters the ultrafine grinding system; S5. Preparing the unqualified fine powder into a base material by a jet mill for later use.

2. The preparation method according to claim 1, wherein In step S1, TFe ≤ 8% and SiO2 ≥ 45% in the magnetic separation iron ore tailings after iron extraction, and TFe ≤ 3% and SiO2 ≥ 35% in the steel slag.

3. The preparation method according to claim 1, characterized in that, In step S2, the magnetic field strength is 0.5 - 1.2 T, the temperature is 550 - 750 °C, and the activation time is 0.5 - 2 h.

4. The preparation method according to claim 1, wherein In step S3, the binder is composed of at least two of bentonite, starch, organic fertilizer and microbial inoculant, and the mass ratio of the activated materials to the binder is 60 - 70:20 - 40.

5. The preparation method according to claim 4, characterized in that, In step S3, the binder is prepared by mixing bentonite, starch, organic fertilizer and microbial inoculant in a mass ratio of 3 - 8:5 - 10:2 - 10:0.1 - 0.

5.

6. The preparation method according to claim 1, characterized in that, In step S4, the intensity of the pulsed magnetic field is 0.8 - 2 T, the frequency is 20 - 80 Hz, the time is 3 - 8 min, the particle size of the qualified particles is 0.5 - 3 mm, and the particle size of the unqualified fine powder is < 0.5 mm.

7. The preparation method according to claim 1, wherein, The D of the base material described in step S5 90 ≤ 15 μm.

8. An activated magnetic mineral soil conditioner prepared by the preparation method according to any one of claims 1 - 7.

9. A base material prepared by the preparation method according to any one of claims 1 - 7.

10. A method for preparing a soilless cultivation substrate, characterized in that, Including mixing the base material according to claim 9, phosphate - solubilizing bacteria and humic acid evenly in a mass ratio of 90 - 95:0.1 - 0.5:2 - 5 to obtain a soilless culture base material.

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