Magnesium flux and preparation method thereof

Abstract

The invention relates to a magnesian flux and a preparation method, and belongs to the technical field of ironmaking production. The magnesium flux comprises the following raw materials in parts by weight: 30-60 parts of cold-rolled magnesium mud and 40-70 parts of magnesium waste refractory. The cold-rolled magnesium mud and the magnesium waste refractory are solid wastes in the steel production process, and are used as main raw materials of the magnesium flux, so that the resource utilization of the wastes is realized, the dependence on natural ore resources is reduced, and the cost of the production raw materials is greatly reduced.

Description

Technical Field

[0001] This application relates to the field of ironmaking production technology, and in particular to a magnesium flux and its preparation method. Background Technology

[0002] The iron and steel metallurgical process, including coking, sintering, pelletizing, ironmaking, steelmaking, and rolling, generates a large amount of solid waste. This solid waste mainly includes metallurgical dust, slag, and scrap refractory materials, containing various elements such as Fe, C, Ca, and Mg. While some of this solid waste has been recycled back into the main process through technological breakthroughs, a significant amount remains unused. In particular, the magnesium molten metal sprayed onto the surface of cold-rolled silicon steel sheets, after being annealed in a ring furnace, produces cold-rolled magnesium sludge, a solid waste. Additionally, magnesium-containing scrap refractory materials that have lost their working properties after use in high-temperature kilns are also present. These are all high-magnesium solid wastes that are currently not effectively utilized.

[0003] In blast furnace smelting, the magnesium required in the slag system mainly comes from sinter. However, with the development of blast furnace burden structures with a high proportion of pellets, further increasing the magnesium flux content in sinter will significantly reduce drum strength and deteriorate dripping performance, thus affecting the yield and quality of sinter. In contrast, increasing the magnesium flux content in pellets can effectively improve the reduction expansion rate of pellets and enhance their metallurgical properties. By adding magnesium flux to the pellets, the amount of flux added externally to the blast furnace can be reduced, thus leading to the rapid development of magnesium pelleting technology. Although existing magnesium pelleting preparation technologies meet the needs of blast furnace smelting to a certain extent, the magnesium flux raw materials used are mostly dependent on natural resources, resulting in high costs. Summary of the Invention

[0004] This application provides a magnesium flux and its preparation method to solve the following technical problem: how to reduce the production cost of existing magnesium fluxes.

[0005] In a first aspect, embodiments of this application provide a magnesium flux, the raw materials of which include: 30 to 60 parts by weight of cold-rolled magnesia mud and 40 to 70 parts by weight of magnesium waste refractory.

[0006] Optionally, the moisture content in the cold-rolled magnesia mud is 20% to 40% by mass.

[0007] Optionally, the mass fraction of dry-based magnesium oxide in the cold-rolled magnesium sludge is ≥70%.

[0008] Optionally, the mass fraction of moisture in the magnesium waste refractory is <3%.

[0009] Optionally, the particle size of the magnesium waste refractory is ≤10mm.

[0010] Optionally, the mass fraction of dry-basis magnesium oxide in the magnesium waste refractory material is ≥50%.

[0011] Optionally, the magnesium flux satisfies at least one of the following properties: Residue on 45μm sieve ≤5%; Specific surface area > 500m² 2 / kg; Moisture content ≤1% by mass; The mass fraction of magnesium oxide is ≥60%.

[0012] Optionally, the magnesium waste refractory material is obtained by crushing, magnetic separation and screening magnesium-containing waste refractory material.

[0013] Secondly, embodiments of this application provide a method for preparing the magnesium flux described in the first aspect, the method comprising: The magnesium-containing waste refractory material is sequentially crushed, magnetically separated, and screened to obtain the magnesium-containing waste refractory material. The magnesium waste refractory and the cold-rolled magnesium sludge are mixed according to the stated mass proportions to obtain a mixture. The mixture is ground and then selected and dried using a hot air process to obtain the magnesium flux.

[0014] Optionally, the particle size of the magnesium-containing waste refractory material is ≤300mm, and the mass fraction of magnesium oxide in the magnesium-containing waste refractory material is 35% to 50%.

[0015] Optionally, the magnetic field strength of the magnetic separation is 2000 Gs to 2500 Gs.

[0016] Optionally, the mass fraction of moisture in the mixture is ≤15%.

[0017] Optionally, the inlet hot air temperature of the vertical mill in the hot air process is 200℃~230℃, and the outlet hot air temperature of the vertical mill in the hot air process is 90℃~110℃.

[0018] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a magnesium flux, the raw materials of which include: 30 to 60 parts by weight of cold-rolled magnesia mud and 40 to 70 parts by weight of magnesium waste refractory. Both cold-rolled magnesia mud and magnesium waste refractory are solid wastes generated during steel production. By using them as the main raw materials for the magnesium flux, the resource utilization of waste is achieved, reducing dependence on natural ore resources and thus significantly lowering production raw material costs. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic flowchart illustrating a method for preparing a magnesium flux provided in an embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range such as 1, 2, 3, 4, 5, and 6, regardless of the range; in addition, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0024] In this document, terms such as “comprising” mean “including but not limited to”. Relational terms such as “first” and “second” are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. “And / or” describes the relationship between related objects, indicating that there can be three relationships, for example, A and / or B can mean: A alone, A and B simultaneously, or B alone; where A and B can be singular or plural. “At least one” means one or more, “more” means two or more; “at least one,” “at least one of the following,” or similar expressions refer to any combination of these items, including any combination of single or plural items; for example, “at least one of a, b, or c,” or “at least one of a, b, and c,” can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. "Parts representation," such as parts by weight or parts by mass, indicates the proportional relationship between components. In the proportional relationships discussed in this article, parameters described by proportion should be understood as the first term of the proportion in the order of description, while the proportion figures should be understood as the second term. For example, if the mass ratio of substance A, substance B, and substance C is 1:2:3, then substances A, B, and C should correspond one-to-one with the proportion figures in the proportion in the order of description, i.e., the mass of substance A : the mass of substance B : the mass of substance C = 1 : 2 : 3.

[0025] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this article can be purchased from the market or prepared by existing methods.

[0026] In a first aspect, embodiments of this application provide a magnesium flux, the raw materials of which include: 30 to 60 parts by weight of cold-rolled magnesia mud and 40 to 70 parts by weight of magnesium waste refractory.

[0027] In this embodiment, cold-rolled magnesia sludge is a magnesium-containing solid waste sludge obtained by annealing magnesium liquid sprayed onto the surface of cold-rolled silicon steel sheets in a ring furnace. Magnesia-containing waste refractory is obtained by crushing, magnetic separation, and screening magnesium-containing waste refractory. Magnesia-containing waste refractory refers to magnesium-containing refractory that has lost its working performance after a period of service during the steelmaking process. Both cold-rolled magnesia sludge and magnesium-containing waste refractory are solid wastes from the steel production process. By using them as the main raw materials for magnesium flux, they can be used as magnesium flux for pelletizing, realizing the resource utilization of magnesium-containing solid waste, reducing the use of natural ore resources, significantly reducing the cost of raw materials, and the produced magnesium flux can meet the requirements of pelletizing.

[0028] In some embodiments, the moisture content in the cold-rolled magnesia mud is 20% to 40% by mass.

[0029] Cold-rolled magnesia with a moisture content within this range exhibits good fluidity, preventing it from clumping due to excessive moisture, which could hinder subsequent processing, or becoming too dry and difficult to mix evenly. A moisture content of 20%–40% in cold-rolled magnesia facilitates effective mixing with magnesia waste refractory materials, improving the homogeneity of the mixture. Excessive moisture content (above 40%) results in overly wet and sticky material, affecting handling and requiring the addition of more magnesia waste refractory materials, thus reducing the overall magnesium content of the mixture. Conversely, insufficient moisture content (below 20%) necessitates a high energy consumption for the pretreatment dehydration process and increases the likelihood of caking.

[0030] In some embodiments, the mass fraction of dry-based magnesium oxide in the cold-rolled magnesium sludge is ≥70%.

[0031] The mass fraction of dry-basis magnesium oxide in cold-rolled magnesia mud refers to the mass fraction of magnesium oxide in the cold-rolled magnesia mud, based on anhydrous magnesia mud. As one of the main raw materials for magnesia flux, the high magnesium content of cold-rolled magnesia mud directly determines the magnesium content level of the final magnesia flux. A dry-basis magnesium oxide mass fraction of ≥70% in cold-rolled magnesia mud ensures that the prepared magnesia flux has sufficient magnesium to meet the high magnesium requirements of metallurgical processes such as pelletizing. A magnesium oxide mass fraction that is too low (below 70%) may reduce the magnesium content of the mixture, thus affecting the blending effect of the magnesia flux.

[0032] In some embodiments, the magnesium waste refractory material is obtained by crushing, magnetic separation and screening magnesium-containing waste refractory material.

[0033] In some embodiments, the mass fraction of moisture in the magnesium waste refractory is <3%.

[0034] Magnesia refractory waste, as another important raw material for magnesium flux, benefits from a moisture content of <3% by mass, which facilitates better and more uniform mixing with other raw materials such as cold-rolled magnesia mud. A moisture content ≥3% by mass may lead to material agglomeration, affecting the mixing effect, while a moisture content of <3% ensures the homogeneity of the mixture and improves the quality of the magnesium flux. Furthermore, a moisture content ≥3% requires a larger amount of magnesium refractory waste to reduce the addition of cold-rolled magnesia mud, thus lowering the overall magnesium content of the mixture.

[0035] In some embodiments, the particle size of the magnesium waste refractory is ≤10mm.

[0036] Smaller particle sizes of magnesia-based waste refractory materials mix more easily with cold-rolled magnesia sludge, ensuring the uniformity of the mixture. This helps to obtain a more uniform powder in subsequent grinding processes, further guaranteeing the quality of the magnesia flux. Particle sizes that are too large (>10mm) can cause uneven mixing, feed blockage, and affect grinding efficiency.

[0037] In some embodiments, the mass fraction of dry-basis magnesium oxide in the magnesium waste refractory material is ≥50%.

[0038] Magnesia-based waste refractory materials are key raw materials for magnesium fluxes, and their high magnesium content helps to increase the magnesium content of the final magnesium flux. Using anhydrous magnesium-based waste refractory materials as a benchmark, a magnesium oxide mass fraction ≥50% in the waste refractory materials ensures that the prepared magnesium flux is rich in magnesium, meeting the demand for high-magnesium fluxes in metallurgical fields such as pelletizing.

[0039] In some embodiments, the magnesium flux satisfies at least one of the following properties: Residue on 45μm sieve ≤5%; Specific surface area > 500m² 2 / kg; Moisture content ≤1% by mass; The mass fraction of magnesium oxide is ≥60%.

[0040] By controlling key indicators such as particle size, specific surface area, and moisture content of magnesium flux, it can meet the production requirements of pellet ore.

[0041] Magnesium fluxes must have a 45μm sieve residue of no more than 5%, meaning that in a sieve test, the amount of magnesium flux particles passing through a 45μm sieve does not exceed 5% of the total. This is an important indicator for measuring the particle size distribution of magnesium fluxes, reflecting the fineness of the flux particles. A sieve residue of ≤5% indicates that most of the particles in the flux are relatively fine, which is beneficial for uniform dispersion and rapid reaction in applications such as pelletizing, thereby improving the flux's performance.

[0042] Large specific surface area (>500m²) 2 A specific surface area ( / kg) means that the flux per unit mass or volume has a larger surface area, thus increasing the contact area between the flux and other components in the pellet. This increased contact area promotes the reaction of the flux with other substances, improves the reaction rate, and contributes to the metallurgical performance of the pellet during the smelting process. Additionally, a large specific surface area (>500 m²) indicates a higher surface area. 2 Magnesium flux at a concentration of ( / kg) can be better dispersed during pellet mixing, avoiding local agglomeration. Good dispersibility ensures uniform distribution of flux in the pellets, thereby improving the overall quality and consistency of the pellets.

[0043] A moisture content greater than 1% by mass can cause magnesium flux to stick together during storage and transportation, easily leading to silo blockage and affecting smooth material feeding. Controlling the moisture content to ≤1% by mass ensures that the magnesium flux maintains good fluidity, avoids silo blockage, and guarantees the continuity and stability of the production process.

[0044] If the magnesium content in magnesium flux is too low (mass fraction of magnesium oxide <60%), it may affect the flux's compatibility.

[0045] Figure 1 This is a schematic flowchart illustrating a method for preparing a magnesium flux provided in an embodiment of this application.

[0046] Please see Figure 1 Secondly, embodiments of this application provide a method for preparing the magnesium flux described in the first aspect, the method comprising: S1. The magnesium-containing waste refractory material is crushed, magnetically separated, and screened sequentially to obtain the magnesium waste refractory material; In this embodiment, the preparation process of magnesium-containing waste refractory includes the following key steps: First, a jaw crusher is used to process the magnesium-containing waste refractory, breaking the low-hardness waste refractory into smaller particles to enrich the magnesium content and separate the magnesium-containing waste refractory from residual iron. Then, magnetic separation technology is used to further remove iron-containing impurities mixed in the magnesium-containing waste refractory, ensuring the purity of the magnesium content. Finally, a vibrating mesh screen is used for fine sieving to select magnesium-containing waste refractory that meets the particle size requirements.

[0047] In some embodiments, the particle size of the magnesium-containing waste refractory material is ≤300mm, and the mass fraction of magnesium oxide in the magnesium-containing waste refractory material is 35% to 50%.

[0048] If the particle size is too large (>300mm), it cannot meet the particle size requirements of the raw material crushed by the jaw crusher; the magnesium content of magnesium-containing waste refractory is the source of magnesium. The mass fraction of magnesium oxide in magnesium-containing waste refractory is 35% to 50%, which can provide enough magnesium to meet the demand of pellet ore for magnesium flux.

[0049] In some embodiments, the magnetic field strength of the magnetic separation is 2000 Gs to 2500 Gs.

[0050] Magnetic separation with a magnetic field strength of 2000 Gs to 2500 Gs can effectively separate residual iron and other magnetic impurities from magnesium-containing waste refractory materials, thereby improving the purity of magnesium flux. Removing these impurities ensures better performance stability of the magnesium flux during subsequent processing and use, reducing potential quality problems caused by impurities. A weak magnetic field strength (<2000 Gs) may result in some residual iron not being removed, damaging the grinding equipment; an excessively strong magnetic field strength (>2500 Gs) will increase the amount of magnetically coated material, causing magnesium loss.

[0051] S2. Mix the magnesium waste refractory and the cold-rolled magnesium sludge according to the stated mass proportions to obtain a mixture; In this embodiment of the application, the magnesium waste refractory and the cold-rolled magnesium sludge are fed into a horizontal strong mixer in proportion and mixed evenly to obtain a mixture.

[0052] Cold-rolled magnesia sludge typically contains high moisture content and has a paste-like consistency, making it difficult to process. Magnesia waste refractory, on the other hand, undergoes pretreatment processes such as crushing, magnetic separation, and screening to remove impurities like residual iron and enrich its magnesium content. Mixing the two in a specific ratio effectively regulates the moisture content and magnesium content of the mixture, resolving the issue of unstable material layers during cold-rolled magnesia sludge grinding, while simultaneously ensuring the quality of the magnesium flux.

[0053] In some embodiments, the mass fraction of moisture in the mixture is ≤15%.

[0054] If the mass fraction of moisture in the mixture is greater than 15%, it is easy to cause the belt to stick and affect the feeding. It will also reduce the efficiency of grinding and drying, and increase the consumption of energy media.

[0055] S3. The mixture is ground and then selected and dried using a hot air process to obtain the magnesium flux.

[0056] In this embodiment of the application, the mixture is conveyed to a vertical mill for powdering, and powder selection and drying are achieved through a hot air process, while homogenization is also achieved to obtain magnesium flux.

[0057] In some embodiments, the inlet hot air temperature of the vertical mill in the hot air process is 200°C to 230°C, and the outlet hot air temperature of the vertical mill in the hot air process is 90°C to 110°C.

[0058] In this embodiment, suitable inlet and outlet air temperatures can ensure that the magnesium flux obtained after grinding the mixture meets the moisture requirements; if the temperature is too high (the inlet hot air temperature of the vertical mill exceeds 230°C and the outlet hot air temperature of the vertical mill exceeds 110°C), the energy consumption of the medium will increase, and the heat resistance of the equipment must also be considered; if the temperature is too low (the inlet hot air temperature of the vertical mill is below 200°C and the outlet hot air temperature of the vertical mill is below 90°C), the drying efficiency will be reduced, and the mass fraction of moisture in the product cannot be guaranteed.

[0059] In this embodiment, the magnesium-containing waste refractory material is mixed with residual iron and other non-magnesium refractory materials, which reduces the magnesium content and affects subsequent processing. Through crushing, magnetic separation, and screening, the residual iron is removed and the magnesium-containing materials are enriched. The cold-rolled magnesia mud has a high moisture content and is in a paste form, making it difficult to utilize. By using magnesium-containing waste refractory material to premix with cold-rolled magnesia mud, the problem of unstable material layer during cold-rolled magnesia mud grinding is solved. Furthermore, by using existing blast furnace slag grinding vertical mill equipment, the grinding and homogenization of magnesium-containing solid waste (magnesium-containing waste refractory material and cold-rolled magnesia mud) are realized. The resulting magnesium flux has a fine particle size, stable composition, and low processing cost, meeting the requirements for pelletizing. Using magnesium-containing solid waste as raw material greatly saves raw material costs.

[0060] The product prepared by the method of preparing magnesium flux is the magnesium flux mentioned above. Since the method of preparing magnesium flux adopts some or all of the technical solutions of the magnesium flux embodiments, it has at least all the beneficial effects brought about by the technical solutions of the magnesium flux embodiments, which will not be elaborated here.

[0061] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0062] Example 1 Prepare 100 tons of cold-rolled magnesia mud and 100 tons of magnesium-containing waste refractory materials. The moisture content of the two materials was tested to be 28.6% and 2.1% by mass, respectively, and the dry basis MgO content was 88.5% and 40.2%, respectively.

[0063] Magnesium-containing waste refractory materials are crushed, magnetically separated, and sieved to obtain magnesium-based waste refractory materials. Testing revealed that the moisture content of the magnesium-based waste refractory materials was 1.6% by mass, and the MgO content was 53.1%. Based on the moisture test results and the moisture requirements for grinding raw materials, the magnesium-based waste refractory materials and cold-rolled magnesia sludge were fed into a horizontal high-intensity mixer at a ratio of 55:45. The mixture was thoroughly mixed to obtain a homogenized material, which was then conveyed to a vertical mill for grinding. The hot air temperature at the inlet of the vertical mill was 215℃, and the hot air temperature at the outlet was 100℃. The hot air was blown in to achieve powder selection and drying, while simultaneously homogenizing, to obtain magnesium flux.

[0064] Example 2 Prepare 100 tons of cold-rolled magnesia mud and 100 tons of magnesium-containing waste refractory materials. The moisture content was tested and found to be 38.9% and 1.8% respectively, and the MgO content was 90.2% and 44.8% respectively.

[0065] Magnesium-containing waste refractory materials are crushed, magnetically separated, and screened to obtain magnesium-based waste refractory materials. Testing revealed that the moisture content of the magnesium-based waste refractory materials was 1.5% and the MgO content was 58.3%. Based on the moisture test results and the moisture requirements for grinding raw materials, the magnesium-based waste refractory materials and cold-rolled magnesia sludge were fed into a horizontal high-intensity mixer at a ratio of 70:30. The mixture was thoroughly mixed to obtain a homogenized material, which was then conveyed to a vertical mill for grinding. The hot air temperature at the inlet of the vertical mill was 227℃, and the hot air temperature at the outlet was 108℃. The hot air was blown in to achieve powder selection and drying, while simultaneously homogenizing the powder to obtain magnesium flux.

[0066] Example 3 Prepare 100 tons of cold-rolled magnesia mud and 100 tons of magnesium-containing waste refractory materials. The moisture content of the two materials was tested to be 21.6% and 2.0% respectively, and the MgO content was 89.6% and 43.2% respectively.

[0067] Magnesium-containing waste refractory materials are crushed, magnetically separated, and sieved to obtain magnesium-based waste refractory materials. Testing revealed that the moisture content of the magnesium-based waste refractory materials was 1.7% and the MgO content was 56.6%. Based on the moisture test results and the required moisture content for grinding raw materials, the magnesium-based waste refractory materials and cold-rolled magnesia sludge were fed into a horizontal high-intensity mixer at a ratio of 40:60. The mixture was thoroughly mixed to obtain a homogenized material, which was then conveyed to a vertical mill for grinding. The hot air temperature at the inlet of the vertical mill was 203℃, and the hot air temperature at the outlet was 91℃. The hot air was blown in to achieve powder selection and drying, while simultaneously homogenizing the powder to obtain magnesium flux.

[0068] Comparative Example 1 Compared with Example 1, the difference between Comparative Example 1 and Example 1 is as follows: Prepare 100 tons of cold-rolled magnesia mud and 100 tons of magnesium-containing waste refractory materials. The moisture content of the two materials was tested to be 52.4% and 2.3% by mass, respectively, and the dry basis MgO content was 87.4% and 41.8%, respectively.

[0069] The mass fraction of moisture in the magnesium waste refractory was 1.6%, and the MgO content was 53.4%.

[0070] Comparative Example 2 Compared with Example 1, the difference between Comparative Example 2 and Example 1 is as follows: Prepare 100 tons of cold-rolled magnesia mud and 100 tons of magnesium-containing waste refractory materials. The moisture content of the two materials was tested to be 27.2% and 2.1% by mass, respectively, and the dry basis MgO content was 87.8% and 40.4%, respectively.

[0071] Magnesium-containing waste refractory materials are enriched without treatment.

[0072] The magnesium fluxes obtained in the examples and comparative examples were tested for magnesium content, 45-micron sieve residue, specific surface area, and moisture content. The results are shown in Table 1.

[0073] Table 1

[0074] As shown in Table 1, the magnesium fluxes provided in the examples all met the requirements for pelletizing. However, Comparative Example 1 used cold-rolled magnesium sludge with a high moisture content, resulting in an excessively high moisture content in the mixture. During implementation, the mixture adhered to the conveyor belt, significantly reducing the grinding and drying efficiency of the vertical mill. Comparative Example 2 used untreated magnesium-containing waste refractory, leading to a decrease in the magnesium content of the prepared magnesium flux, failing to meet the usage requirements. Furthermore, the excessively large particle size of some raw materials affected grinding efficiency, resulting in an increase in the 45μm sieve residue and a decrease in specific surface area.

[0075] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages: The embodiments of the present invention use magnesium-containing solid waste (magnesium waste refractory and cold-rolled magnesia mud) as raw materials, which greatly reduces the cost of raw materials for production and has significant economic advantages compared with the traditional method of using natural mineral resources.

[0076] The magnesium flux and preparation method provided in this invention utilize existing blast furnace slag grinding vertical mills to grind and homogenize magnesium-containing solid waste. The resulting magnesium flux has fine particle size, stable composition, and low processing cost, meeting the requirements for pelletizing.

[0077] The embodiments of this invention realize the resource utilization of magnesium solid waste from steel plants, reduce the pollution of the environment caused by solid waste accumulation, comply with the requirements of environmental protection policies and regulations, and promote the construction of "steel solid waste leaving the plant" and "zero-waste group".

[0078] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A magnesium flux, wherein the raw materials of the magnesium flux include: 30 to 60 parts by weight of cold-rolled magnesia mud and 40 to 70 parts by weight of magnesia waste refractory.

2. The magnesium flux according to claim 1, characterized in that, The cold-rolled magnesium sludge has a moisture content of 20%–40% by mass; and / or, The mass fraction of dry-based magnesium oxide in the cold-rolled magnesium sludge is ≥70%.

3. The magnesium flux according to claim 1, characterized in that, The mass fraction of moisture in the magnesium waste refractory is <3%; and / or, The particle size of the magnesium waste refractory is ≤10mm; and / or, The mass fraction of dry-basis magnesium oxide in the magnesium-based waste refractory material is ≥50%.

4. The magnesium flux according to claim 1, characterized in that, The magnesium flux satisfies at least one of the following properties: Residue on 45μm sieve ≤5%; Specific surface area > 500m² 2 / kg; Moisture content ≤1% by mass; The mass fraction of magnesium oxide is ≥60%.

5. The magnesium flux according to claim 1, characterized in that, The magnesium-containing waste refractory material is obtained by crushing, magnetic separation and screening magnesium-containing waste refractory material.

6. A method for preparing the magnesium flux according to any one of claims 1 to 5, the method comprising: The magnesium-containing waste refractory material is sequentially crushed, magnetically separated, and screened to obtain the magnesium-containing waste refractory material. The magnesium waste refractory and the cold-rolled magnesium sludge are mixed according to the stated mass proportions to obtain a mixture. The mixture is ground and then selected and dried using a hot air process to obtain the magnesium flux.

7. The method according to claim 6, characterized in that, The particle size of the magnesium-containing waste refractory material is ≤300mm, and the mass fraction of magnesium oxide in the magnesium-containing waste refractory material is 35% to 50%.

8. The method according to claim 6, characterized in that, The magnetic field strength of the magnetic separation is 2000 Gs to 2500 Gs.

9. The method according to claim 6, characterized in that, The mass fraction of moisture in the mixture is ≤15%.

10. The method according to claim 6, characterized in that, The inlet hot air temperature of the vertical mill in the hot air process is 200℃~230℃, and the outlet hot air temperature of the vertical mill in the hot air process is 90℃~110℃.

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