Soil conditioner prepared by modifying high-phosphorus smelting slag and method

Abstract

The invention belongs to the field of soil treatment, and particularly relates to a soil conditioner prepared by modifying high-phosphorus smelting slag and a method, the method comprises the following steps: S1, according to the composition of the high-phosphorus slag, uniformly mixing an additive with the high-phosphorus slag, adjusting the binary alkalinity of appropriate end-point slag to 1.0-2.0, and then grinding to obtain uniformly mixed metallurgical slag; wherein the content of phosphorus in the high-phosphorus slag is 1%-10%, and the content of FeO is 5%-50%; s2, the metallurgical slag is put into a heating furnace to be heated, the heating temperature ranges from 1500 DEG C to 1800 DEG C, and after all substances are molten into a liquid state and heat preservation is conducted for 30 min to 1.5 h, the molten slag is rapidly cooled to the room temperature; s3, the slag obtained in the S2 is dried and finely ground, and then the soil conditioner is obtained. According to the method, the originally waste metallurgical high-phosphorus slag is utilized in a high-value mode, a large number of precious P resources are recycled, and the method is worthy of being widely applied and popularized.

Description

Technical Field

[0001] The invention belongs to the field of soil treatment, and in particular relates to a soil conditioner prepared by modifying high-phosphorus smelting slag and a method thereof. Background Art

[0002] Soil conditioners are of great significance in soil management. They can effectively improve the physical and chemical properties of soil, such as increasing soil aeration, water permeability and water retention, thereby creating a more suitable environment for crop growth. Soil conditioners can also balance soil pH, regulate nutrient supply, promote the activity of beneficial microorganisms, and keep the soil healthy. This not only helps to increase crop yields and quality, but also reduces excessive dependence on chemical fertilizers and water resources, promotes the development of eco-friendly agriculture, and provides important support for ensuring food security and protecting the environment.

[0003] High-phosphorus iron ore resources are widely distributed around the world, and the world's proven high-phosphorus oolitic iron ore reserves are greater than 20 billion tons. With the rapid consumption of high-quality iron ore and the continuous advancement of smelting technology, high-phosphorus iron ore resources that were originally difficult to use have gradually become another direction for expanding the selection of ironmaking raw materials. Therefore, the phosphorus content in the metallurgical slag produced during the smelting process continues to increase, and the internal circulation of steel plants will cause the cyclic enrichment of phosphorus in the slag, so the development and utilization of high-phosphorus metallurgical slag is urgent.

[0005] In addition, the inventor's research group has been conducting research on the development of efficient smelting technology for high-phosphorus iron ore and high-value utilization of solid waste in the metallurgical industry. In-depth cooperation has been carried out with the Algerian high-phosphorus iron ore smelting construction project, intending to develop a production process that meets the characteristics of its resource structure. In view of the country's natural resource characteristics of rich high-phosphorus iron ore and natural gas resources, in previous studies, this research group has disclosed a two-step method for efficient separation of iron and phosphorus from high-phosphorus iron-containing resources based on gas-based energy (patent number ZL 2020104955182). With the continuous in-depth research of the project, it was found that by smelting high-phosphorus iron ore by this method, an average of 1 ton of high-phosphorus smelting slag will be produced for every ton of steel produced, which contains about 60-120kg of phosphorus. If it is discarded at will, it will cause a large amount of precious phosphorus resources. Algeria is mainly dominated by Mediterranean and desert climates. The desert area is dry and rainy, and water resources are very precious in this area. Combining the characteristics of the smelting process and national resource conditions, it is very meaningful to develop and utilize a large amount of high-phosphorus smelting slag produced by smelting to simultaneously achieve phosphorus recovery and soil water retention. Summary of the invention

[0006] In order to achieve the above objectives and solve the above problems, the technical solution of the present invention provides a soil conditioner and method prepared by modifying high-phosphorus smelting slag. By modulating and modifying phosphorus slag (for example, molten slag produced by a rapid reduction smelting process), a glass phase soil conditioner with a porous structure is generated. On the one hand, the recycling of high-phosphorus metallurgical slag, a solid waste of the metallurgical industry, is achieved to improve the soil. After activation treatment, the phosphorus and calcium elements in the slag can be slowly released into the soil, maintaining a high moisture content for the soil while providing a variety of beneficial nutrients. On the other hand, it also solves the problem of low utilization rate of phosphorus-containing slag produced after smelting high-phosphorus iron ore and large waste of phosphorus-containing resources.

[0007] According to a first aspect of the technical solution of the present invention, there is provided a method for preparing a soil conditioner by modifying high-phosphorus smelting slag, comprising:

[0008] S1. According to the composition of the high-phosphorus smelting slag, the additive is uniformly mixed with the high-phosphorus smelting slag, and the binary basicity of the appropriate end-point slag is adjusted to 1.0-2.0, and then ground to obtain a uniformly mixed metallurgical slag;

[0009] S2, the metallurgical slag is placed in a heating furnace and heated until all the substances are melted into liquid state, and the slag is quickly cooled to room temperature after heat preservation;

[0010] S3, drying and finely grinding the slag to obtain a soil conditioner.

[0011] It should be noted that the soil conditioner in the technical solution of the present application specifically refers to a soil conditioner that can slowly release fertilizer and has a water retention function.

[0012] Furthermore, the high-phosphorus smelting slag in S1 is smelting slag produced by a rapid reduction smelting process, ironmaking and steelmaking slag produced in a long-process smelting process, or high-phosphorus slag produced by various industries.

[0013] Furthermore, the rapid reduction melting process specifically includes:

[0014] Add high-phosphorus iron-containing resources, carburizing agent, flux, and binder according to a predetermined ratio and mix them, add appropriate amount of water to moisten them, mix them again and press them into agglomerates with a certain compressive strength, wherein the carburizing agent is anthracite or coke powder, wherein the fixed carbon is about 80%, the ash content is less than 15%, and the particle size is less than 1mm, wherein the maximum basicity of the agglomerate is 2.0, the internal carburizing agent is 0-2% of the weight of the iron-containing material, and the flux is limestone and industrial-grade sodium carbonate, and the proportion of industrial-grade sodium carbonate is 0-3% of the weight of the iron-containing material;

[0015] After drying, the briquettes are placed in a vertical furnace for gas-based reduction. The reducing gas comes from the reforming of natural gas and the tail gas of the reduction furnace to obtain metallized briquettes.

[0016] The metallized agglomerates are discharged and directly hot-charged into a smelting furnace for rapid smelting by means of natural gas combustion, plasma torch or arc heating. After water quenching and magnetic separation, solid granular pig iron and glass slag are produced. Among them, the gas-based smelting furnace uses a natural gas burner to quickly heat the metallized agglomerates to achieve rapid slag iron melting. The liquid pig iron or semi-steel and slag after melting are quickly discharged into a water pool for water quenching, thereby obtaining molten slag.

[0017] Furthermore, the high-phosphorus smelting slag is in a solid state or a high-temperature molten state.

[0018] Furthermore, the phosphorus content of the high-phosphorus smelting slag is 1%-10%, and the FeO content is 5%-50%. At the same time, the slag does not contain heavy metal elements that pollute the soil.

[0019] Preferably, the main component FeO content in the high-phosphorus smelting slag is 10%, P content is 5%, MgO content is 5%, Al2O3 content is 10.5%, CaO and SiO2 content are both about 30%, and C content is 2%.

[0020] Furthermore, the suitable binary basicity of the terminal slag in S1 is 1.7-2.0.

[0021] Furthermore, the additive in S1 is an alkalinity regulator.

[0022] Furthermore, the alkalinity regulator in S1 is quartz (SiO2), quicklime (CaO) or limestone (CaCO3).

[0023] Furthermore, in S2, the heating temperature is 1500°C-1800°C; the insulation time after complete melting is 30min-1.5h, and nitrogen is used as the protective gas.

[0024] Furthermore, the rapid cooling in S2 is air cooling, atomization cooling or water cooling.

[0025] Furthermore, the cooling time to room temperature in S2 is 5s-30s, so as to control the proportion of amorphous phase in the slag to be greater than 30%.

[0026] Furthermore, the particle size of the soil conditioner after fine grinding in S3 is between 50 meshes and 300 meshes.

[0027] Furthermore, in S3, the soil conditioner is evenly dispersed 2-15 cm below the soil surface.

[0028] Furthermore, in S3, the amount of the soil conditioner used is 100-2000 kg / mu.

[0029] According to a second aspect of the technical solution of the present invention, there is provided a soil conditioner prepared by modifying high-phosphorus smelting slag, wherein the soil conditioner is prepared by the method described in any one of the above aspects.

[0030] Furthermore, the soil conditioner has a citric acid-soluble phosphorus content of 20-80%.

[0031] Compared with the prior art, the preparation method of the soil conditioner in the technical solution of the present invention is simple, and the high-phosphorus metallurgical slag is modified by modifying the slag composition and physical state, combined with the adjustment of the metallurgical slag alkalinity and cooling rate. The amorphous phase in the modified soil conditioner not only increases the specific surface area of ​​the slag, can preserve moisture and inhibit the evaporation of moisture, but also the amorphous phase will combine with water to produce hydrates, further inhibiting water loss, and the water retention is significantly better. At the same time, the soil conditioner that has been modified and activated can slowly release nutrients such as Ca, Si, and P in the soil, providing plants with slow-release inorganic fertilizers, which is particularly suitable for areas with arid climates and poor land, ensuring a slow-release effect. The method of the present invention makes high-value use of the originally discarded metallurgical high-phosphorus slag, recovers a large amount of precious P resources, and is worthy of vigorous promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0033] Figure 1 A flow chart showing a method for preparing a soil conditioner by modifying high-phosphorus smelting slag according to an embodiment of the technical solution of the present invention is shown;

[0034] Figure 2 A schematic diagram showing the slag after modulation and modification according to one embodiment of the technical solution of the present invention;

[0035] Figure 3 A schematic diagram showing the effect of slags with different basicities on citrate-soluble phosphorus and water-soluble phosphorus;

[0036] Figure 4 A schematic diagram showing the water retention effect of an embodiment of the technical solution of the present invention and a blank control group is shown.

[0037] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0038] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0039] The terms "first", "second", etc. in the specification and claims of the present disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein, for example.

[0040] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0041] Multiple includes two or more.

[0042] It should be understood that the term "and / or" used in this disclosure is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone.

[0043] The technical solution of the present invention provides a soil conditioner and method for preparing by modifying high-phosphorus smelting slag. The high-phosphorus metallurgical slag is reconstructed by controlling the alkalinity and cooling rate to prepare a soil conditioner with both water retention and nutrient release functions. This is an innovative and practical method. Compared with the method of enriching phosphorus in crystallized slag, the operation of modulating metallurgical slag by this method is simpler and more efficient, and the nutrient element slow release effect is significantly better, the water retention is significantly better, and no other waste is generated in the whole process.

[0044] Specifically, the technical solution of the present invention first provides a method for preparing a soil conditioner by modifying high-phosphorus smelting slag, and by modifying the slag composition and physical state, combined with the adjustment of the metallurgical slag basicity and cooling rate, etc., the ratio of amorphous phase and crystalline phase in the slag is adjusted, so that the adjusted slag has the characteristics of nutrient slow release and moisture retention. Figure 1 As shown, the specific steps include:

[0045] S1. According to the composition of high-phosphorus smelting slag, the additive is uniformly mixed with the high-phosphorus smelting slag, and the binary basicity of the appropriate terminal slag is adjusted to obtain a uniformly mixed metallurgical slag.

[0046] In a preferred embodiment, the high-phosphorus smelting slag in S1 is smelting slag produced by a rapid reduction smelting process, ironmaking and steelmaking slag produced in a long-process smelting process, or high-phosphorus slag produced by various industries.

[0047] In a preferred embodiment, the rapid reduction melting process specifically includes:

[0048] Add high-phosphorus iron-containing resources, carburizing agent, flux, and binder according to a predetermined ratio and mix them, add appropriate amount of water to moisten them, mix them again and press them into agglomerates with a certain compressive strength, wherein the carburizing agent is anthracite or coke powder, wherein the fixed carbon is about 80%, the ash content is less than 15%, and the particle size is less than 1mm, wherein the maximum basicity of the agglomerate is 2.0, the internal carburizing agent is 0-2% of the weight of the iron-containing material, and the flux is limestone and industrial-grade sodium carbonate, and the proportion of industrial-grade sodium carbonate is 0-3% of the weight of the iron-containing material;

[0049] After drying, the briquettes are placed in a vertical furnace for gas-based reduction. The reducing gas comes from the reforming of natural gas and the tail gas of the reduction furnace to obtain metallized briquettes.

[0050] The metallized agglomerates are discharged and directly hot-charged into a smelting furnace for rapid smelting by means of natural gas combustion, plasma torch or arc heating. After water quenching and magnetic separation, solid granular pig iron and glass slag are produced. Among them, the gas-based smelting furnace uses a natural gas burner to quickly heat the metallized agglomerates to achieve rapid slag iron melting. The liquid pig iron or semi-steel and slag after melting are quickly discharged into a water pool for water quenching, thereby obtaining molten slag.

[0051] Here, compared with natural gas combustion heating, the use of plasma torch or arc heating can achieve a faster heating effect. Using plasma torch or arc heating, the heating temperature can reach 1450℃-1800℃, and the melting time can be further shortened to 5-8min. The higher heating temperature significantly improves the recovery rate and dephosphorization rate of metallic iron during the smelting process. Furthermore, the glass phase ratio and nutrient element content in the conditioner prepared based on the smelting slag are more conducive to enhancing its water retention and nutrient slow release effect.

[0052] When using plasma heating, the specific parameters are shown in Table 1 below:

[0053] Table 1 Plasma melting process parameters

[0054]

[0055] In a preferred embodiment, the high-phosphorus smelting slag is in a solid state or a high-temperature molten state.

[0056] In a preferred embodiment, the phosphorus content of the high-phosphorus smelting slag is 1%-10%, and the FeO content is 5%-50%. In addition, the slag does not contain heavy metal elements that may pollute the soil.

[0057] In a preferred embodiment, the suitable binary basicity of the end slag in S1 is 1.0-2.0.

[0058] Here, binary alkalinity refers to the mass ratio of the main alkaline oxide CaO to the main acidic oxide SiO2 in the slag. This ratio represents some basic properties of the slag, such as fluidity, the interaction between the elements in the slag, etc. In the technical solution of the present application, a too high proportion of free CaO in the slag will lead to a decrease in the activity of the slag, and increase the melting point of the slag, and more crystalline phases will be produced during the cooling process, affecting the element leaching effect of the soil conditioner; while too low alkalinity will reduce the phosphorus capacity of the slag, thereby affecting the effective phosphorus content in the soil conditioner and reducing the release effect of the P element.

[0059] like Figure 3 As shown, when the slag basicity is 0.8, the citric acid solubility of the slag is 20.67%, and the citric acid solubility is low. The phosphorus release amount of the soil conditioner is not enough, and the effect of slow release of nutrients cannot be achieved. When the slag basicity is greater than 2, although the citric acid-soluble phosphorus content is relatively large, the slag phase is difficult to melt due to the excessive free CaO content in the slag. In addition, a large amount of free CaO will cause the water-quenched slag crystalline phase content to be too large, and a large amount of nutrients are fixed by the crystalline phase. Although the citric acid solubility increases, the nutrient release rate decreases, making it difficult to play the role of a soil conditioner. Among them, when the slag basicity is higher than 1.7, the citric acid solubility content is relatively high, and at the same time, a suitable nutrient release rate is guaranteed. Therefore, the suitable basicity range of this slag phase is 1.0-2.0, preferably 1.7-2.0.

[0060] Furthermore, the additive in S1 is an alkalinity regulator.

[0061] Furthermore, the alkalinity regulator in S1 is quartz (SiO2), quicklime (CaO) or limestone (CaCO3).

[0062] S2, placing the metallurgical slag in a heating furnace and heating it until all the substances are melted into liquid state, and then the molten slag is quickly cooled to room temperature after heat preservation.

[0063] In a preferred embodiment, the heating temperature in S2 is 1500° C.-1800° C. to ensure that the solid slag and additives are completely melted; the insulation time after complete melting is 30 min-1.5 h.

[0064] Here, the melting point of SiO2 or CaO alone is very high, up to more than 2000°C. Only when the proportions of the components in the slag are appropriate and low-melting-point compounds (Ca2SiO2, etc.) are formed can the melting point of the slag be lowered and its fluidity be improved. When the heating temperature is low, the components in the slag are not fully melted, and high heating temperature will cause energy waste. More importantly, when the alkalinity is not suitable during the slag melting process, or the heating temperature is not enough to completely melt the slag phase, the elements and crystal structures in the soil conditioner are unevenly distributed, which will increase the difficulty of the subsequent fine grinding process and make it difficult to release the nutrients in the soil conditioner during subsequent use.

[0065] In a preferred embodiment, the rapid cooling in S2 is air cooling, mist cooling or water cooling.

[0066] In a preferred embodiment, the cooling time to room temperature in S2 is 5s-30s, so as to control the proportion of amorphous phase in the slag to be greater than 30%. In a preferred embodiment, the cooling time to room temperature in S2 is 5s.

[0067] Here, the atoms or molecules inside the crystal are arranged periodically, while the non-crystal has the characteristics of short-range order but long-range disorder. Crystals are much more stable than non-crystals, so by modifying the ratio of crystals to non-crystals in soil conditioners, the leaching rate of nutrients in the conditioner can be indirectly controlled.

[0068] S3, drying the slag after cooling to room temperature, and grinding it into fine powder to obtain a soil conditioner.

[0069] In a preferred embodiment, S3 further comprises spreading the soil conditioner evenly on the soil surface, and mixing the soil conditioner and the soil evenly by tilling.

[0070] In a preferred embodiment, the particle size of the soil conditioner after fine grinding in S3 is between 50 mesh and 300 mesh.

[0071] Here, the particle size setting fully considers the particle size composition of soil particles. Too fine particles will lead to a higher soil density, which is not conducive to water penetration; while larger conditioner particles will lead to a smaller specific surface area of ​​the particles, hindered element leaching, and too fast water loss.

[0072] In a preferred embodiment, in S3, the soil conditioner is evenly dispersed 2-15 cm below the soil surface.

[0073] In a preferred embodiment, in S3, the amount of the soil conditioner used is 100-2000 kg / mu.

[0074] The technical solution of the present invention also provides a soil conditioner prepared by modifying high-phosphorus smelting slag, wherein the soil conditioner is prepared according to the method described above.

[0075] Example 1

[0076] The raw material conditions are: high-phosphorus smelting slag obtained from smelting Algerian high-phosphorus iron ore in the laboratory. The project is the applicant's project in Algeria;

[0077] The Jabilit iron ore mine is located in Tindouf Province in southwestern Algeria. It is a giant iron ore with a reserve of 1.6 billion tons and an average iron grade of 53%. However, the iron ore of the mine contains high phosphorus and is limited by the mineral processing and dephosphorization technology. It was not until recently that it was jointly developed with relevant Chinese companies.

[0078] The molten slag is obtained through a rapid reduction smelting process, which contains a large amount of valuable nutrients. In order to utilize this industrial waste slag and jointly control the local desertification soil problem, a soil conditioner with both water retention and nutrient slow release prepared using this metallurgical slag has been developed.

[0079] The main components of high-phosphorus metallurgical slag are FeO content of 10%, P content of 5%, MgO content of 5%, Al2O3 content of 10.5%, CaO and SiO2 content of about 30% each, and C content of 2%.

[0080] Select 100g of high-phosphorus metallurgical slag as shown in the composition. According to the content of CaO and SiO2 in the composition, in order to make the alkalinity of the high-phosphorus slag after remelting 1.7, add 21g of quicklime reagent (CaO). The mixed reagents are preliminarily ground in a crucible so that the slag phase and the quicklime additive can be fully melted during the heating process. Use a molybdenum crucible with a graphite sleeve to hold the ground mixed slag and put it into a muffle furnace. Adjust the heating rate of the muffle furnace to 10℃ / min, the end temperature to 1600℃, keep warm for 1h, and use nitrogen as the protective gas. After the heating is completed, quickly take out the slag from the muffle furnace and quickly pour it into the cooling water. Take out the remelted slag cooled to room temperature and dry it. Finely grind it to 200 mesh to obtain the prepared soil conditioner, such as Figure 2 As shown. The content of citric acid-soluble phosphorus obtained by testing according to GB / T8573-2017 standard is 55.78%. 100g of the prepared soil conditioner was mixed with 1000g of poor sandy soil so that the soil conditioner was evenly distributed 2-5cm below the surface of the soil in the pot. At the same time, a blank control group of soil pots with 1100g of the same sandy soil was prepared. After fully watering the two groups of soil pots, they were placed outdoors and left to stand. After 10 days, the soil in the blank control group was completely dry, while the soil under the surface of the soil pots with soil conditioners was still moist, so the water retention was very good (such as Figure 4As shown, the left side is the group with soil water retaining agent added, and the right side is the group without soil water retaining agent added). At the same time, subsequent experiments have verified that the penetration rate of nutrient elements is better, which makes the crop growth have a significant advantage over the blank control group.

[0081] In summary, the present invention discloses a method for preparing a soil conditioner by modifying high-phosphorus metallurgical slag. The method comprises: adding phosphorus-containing metallurgical slag and alkalinity regulator in a predetermined proportion and mixing; after high-temperature melting and cooling, the molten liquid slag is subjected to water quenching and fine grinding activation treatment to produce a glassy inorganic water-retaining agent with a porous structure. The method of the present invention has the characteristics of simple preparation process, strong adaptability of raw materials and low cost. The prepared soil conditioner has a porous surface and has a very high adsorption effect on water. It can slowly release nutrients such as P and Ca in the soil, which is conducive to plant growth. It is a high-quality material that integrates the functions of soil water retention and slow-release fertilizer, and is of great significance in the comprehensive utilization of metallurgical slag and soil improvement.

[0082] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a soil conditioner by modifying high-phosphorus smelting slag, characterized in that: include: S1. According to the composition of high-phosphorus smelting slag, the additive is uniformly mixed with the high-phosphorus smelting slag, the binary basicity of the appropriate terminal slag is adjusted to 1.0-2.0, and then ground to obtain a uniformly mixed metallurgical slag; wherein the phosphorus content of the high-phosphorus smelting slag is 1%-10%, and the FeO content is 5%-50%; S2, the metallurgical slag is placed in a heating furnace and heated at a temperature of 1500°C-1800°C. After all the substances are melted into liquid and kept warm for 30min-1.5h, the slag is quickly cooled to room temperature; S3, drying and finely grinding the slag obtained in S2 to obtain a soil conditioner.

2. The method according to claim 1, characterized in that In S1, the high-phosphorus smelting slag is smelting slag produced by a rapid reduction smelting process or ironmaking or steelmaking slag produced in a long process smelting process; Wherein, the high-phosphorus smelting slag in S1 is in a solid state or a high-temperature molten state.

3. The method according to claim 2, characterized in that The rapid reduction melting process specifically comprises: High-phosphorus iron-containing resources, carburizing agent, flux, and binder are added and mixed according to a predetermined ratio, and then moistened with a proper amount of water. After mixing again, the mixture is pressed into a mass with a certain compressive strength, wherein the carburizing agent is anthracite or coke powder, wherein the fixed carbon content is about 80%, the ash content is less than 15%, and the particle size is less than 1 mm; wherein the maximum basicity of the mass is 2.0, the carburizing agent is 0-2% of the weight of the iron-containing material, and the flux is limestone and industrial-grade sodium carbonate, wherein the proportion of industrial-grade sodium carbonate is 0-3% of the weight of the iron-containing material; After drying, the briquettes are placed in a vertical furnace for gas-based reduction. The reducing gas comes from the reforming of natural gas and the tail gas of the reduction furnace to obtain metallized briquettes. The metallized agglomerates are discharged and directly hot-charged into a smelting furnace for rapid smelting by means of natural gas combustion, plasma torch or arc heating. After water quenching and magnetic separation, solid granular pig iron and glass slag are produced. Among them, the gas-based smelting furnace uses a natural gas burner to quickly heat the metallized agglomerates to achieve rapid slag iron melting. The liquid pig iron or semi-steel and slag after melting are quickly discharged into a water pool for water quenching, thereby obtaining molten slag.

4. The method according to claim 1, characterized in that: The suitable binary basicity of the terminal slag in S1 is 1.7-2.

0.

5. The method according to claim 1, characterized in that The additive in S1 is an alkalinity regulator; Wherein, the alkalinity regulator is quartz (SiO2), quicklime (CaO) or limestone (CaCO3).

6. The method according to claim 1, characterized in that The rapid cooling in S2 is air cooling, mist cooling or water cooling.

7. The method according to claim 1, characterized in that The time for cooling to room temperature in S2 is 5s-30s, so as to control the proportion of amorphous phase in the slag to be greater than 30%.

8. The method according to claim 1, characterized in that The particle size of the finely ground soil conditioner in S3 is between 50 mesh and 300 mesh, and is evenly dispersed 2-15 cm below the soil surface; Wherein, the dosage of the soil conditioner is 100-2000kg / mu.

9. A soil conditioner prepared by modifying high-phosphorus smelting slag, wherein: The soil conditioner is prepared by the method according to any one of claims 1 to 8.

10. The soil conditioner according to claim 9, characterized in that The soil conditioner has a citric acid-soluble phosphorus content of 20-80%.

Images