A method of producing magnesium-zinc alloy and magnesium-zinc-aluminum spinel by simultaneous aluminothermic reduction

Abstract

The application provides a method for preparing magnesium-zinc alloy and magnesium-zinc-aluminum spinel by synchronous aluminum thermal reduction, and belongs to the field of alloy metallurgy. The method uses magnesium oxide powder and zinc oxide powder as direct raw materials, aluminum powder as a reducing agent, and obtains pellets by mixing and pressing; the pellets are placed in a vacuum reduction device with a condensation crystallizer to perform synchronous aluminum thermal reduction, magnesium oxide and zinc oxide are simultaneously reduced by aluminum to generate magnesium vapor and zinc vapor, the two-phase vapor completes alloying under gaseous conditions and is condensed to form a crude magnesium-zinc alloy; the reduction slag is treated by high-temperature calcination or melting to obtain a magnesium-zinc-aluminum spinel byproduct. The crude magnesium-zinc alloy is refined by melting to obtain a magnesium-zinc alloy ingot, wherein the zinc content is 0.5-50 wt.%, and the total impurity content is ≤0.5 wt.%. The application synchronously obtains magnesium-zinc alloy with uniform composition and high-value spinel byproduct through a single reduction process, the process is simple, zinc burning loss is small, resource utilization rate is high, and industrialization is easy.

Description

Technical Field

[0001] This application relates to the field of alloy metallurgy technology, and in particular to a method for preparing magnesium-zinc alloys and magnesium-zinc-aluminum spinel by simultaneous aluminothermic reduction. Background Technology

[0002] Magnesium-zinc alloys possess characteristics such as low density, high specific strength, excellent corrosion resistance, and biocompatibility, showing broad application prospects in aerospace, transportation, and biomedical materials. Zinc, a commonly used alloying element in magnesium alloys, can significantly improve their mechanical properties and corrosion resistance. Magnesium-zinc-aluminum spinel (MgO-ZnO-Al2O3 ternary spinel system) is a functional material with excellent thermal stability, high hardness, chemical corrosion resistance, and good optical properties, widely used in refractory materials, ceramic pigments, catalyst supports, and electronic packaging. If the synergistic preparation of magnesium-zinc alloys and magnesium-zinc-aluminum spinel can be achieved, it will not only reduce production costs but also improve the comprehensive utilization of resources.

[0003] Currently, the main method for preparing magnesium-zinc alloys is the smelting of metallic magnesium and zinc. This method is prone to zinc volatilization and burn-off at high temperatures, making alloy composition control difficult and resulting in high overall energy consumption. Some studies have attempted to purify or prepare magnesium-zinc alloys using vacuum distillation or gas-phase methods, but these methods still require high-purity metallic magnesium and zinc as raw materials, demanding strict control over raw material purity, equipment sealing, and multi-temperature zone heating systems. The processes are complex, and equipment investment and operating costs remain high. More importantly, existing technologies do not consider the disposal and utilization of reduction slag, resulting in the direct discharge of large amounts of aluminum and magnesium-containing solid waste, causing resource waste and environmental pollution. Therefore, there is an urgent need to develop a method that can directly use inexpensive oxides (such as magnesium oxide and zinc oxide) as raw materials to simultaneously prepare homogeneous magnesium-zinc alloys in a single reduction process, while converting the reduction slag into high-value-added magnesium-zinc-aluminum spinel. This would solve the fundamental problems of high raw material costs, severe zinc burn-off, difficulty in controlling alloy composition, and low resource utilization in existing technologies. Summary of the Invention

[0004] This application provides a method for preparing magnesium-zinc alloys and magnesium-zinc-aluminum spinel by simultaneous aluminothermic reduction, which solves the following technical problem: how to use oxides as direct raw materials to simultaneously prepare magnesium-zinc alloys with uniform composition through a single reduction process, and to convert the reduction slag into high-value-added by-products.

[0005] This application provides a method for preparing magnesium-zinc alloy and magnesium-zinc-aluminum spinel by simultaneous aluminothermic reduction, the method comprising: Magnesium source raw materials and zinc source raw materials are processed separately to obtain magnesium oxide powder and zinc oxide powder; According to the chemical composition of the target magnesium-zinc alloy, the magnesium oxide powder, the zinc oxide powder, and the aluminum powder are mixed and formulated to obtain a mixture; The mixture is pressed to obtain pellets; Under set temperature and set vacuum conditions, the pellets are subjected to simultaneous aluminothermic reduction so that magnesium oxide and zinc oxide in the pellets are simultaneously reduced by aluminum to generate magnesium vapor and zinc vapor. The magnesium vapor and the zinc vapor are alloyed under gaseous conditions and condensed to form crude magnesium-zinc alloy. The set temperature is 700℃~1250℃ and the set vacuum degree is 0.01Pa~10Pa. The reduction slag after synchronous aluminothermic reduction is subjected to high-temperature calcination or melting treatment to obtain magnesium zinc aluminum spinel by-product.

[0006] Optionally, the method further includes: Under a protective atmosphere or covering agent conditions, the crude magnesium-zinc alloy is smelted, refined, and cast to obtain a magnesium-zinc alloy ingot; the smelting temperature is 400℃~800℃, the covering agent includes at least one of chloride salts and fluoride salts, and the total mass fraction of impurity elements in the magnesium-zinc alloy ingot is ≤0.5%.

[0007] Optionally, the magnesium source material includes at least one of magnesium oxide, magnesite, dolomite, magnesium hydroxide, basic magnesium carbonate, magnesium chloride, and magnesium sulfate.

[0008] Optionally, the zinc source material includes at least one of zinc oxide, smithsonite, basic zinc carbonate, zinc hydroxide, zinc sulfate, and zinc chloride.

[0009] Optionally, the target magnesium-zinc alloy contains 0.5% to 50% zinc by mass.

[0010] Optionally, the amount of aluminum powder added is 1.0 to 1.5 times the theoretical amount of aluminum powder to be added, where the theoretical amount of aluminum powder to be added is the mass of aluminum powder required for the complete reduction of magnesium oxide and zinc oxide.

[0011] Optionally, the pressing is performed using a double-roller briquetting machine, the pressing pressure is 50MPa to 300MPa, and the pressing roller speed is 3r / min to 30r / min.

[0012] Optionally, the reaction time for the simultaneous aluminothermic reduction is 0.5 h to 6 h.

[0013] Optionally, the magnesium zinc aluminum spinel byproduct is a ternary spinel system of MgO-ZnO-Al2O3.

[0014] Optionally, the simultaneous aluminothermic reduction employs a vacuum reduction device with a condenser crystallizer, the device comprising: Vacuum reduction furnace; A heating device is used to heat the vacuum reduction furnace; The condenser crystallizer is connected to the vacuum reduction furnace via a connecting device; A cooling device is used to cool the condenser crystallizer; The pellets are placed inside the vacuum reduction furnace.

[0015] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a method for simultaneously preparing magnesium-zinc alloy and magnesium-zinc-aluminum spinel by aluminothermic reduction. By utilizing the same aluminothermic reduction process, magnesium and zinc are extracted from oxide raw materials and directly alloyed in the gaseous state to obtain magnesium-zinc alloy, while the reduction slag is converted into magnesium-zinc-aluminum spinel. This achieves the goal of simultaneously preparing two high-value-added products using oxides as direct raw materials and a single reduction process.

[0016] The specific reaction process is as follows: First, the magnesium and zinc source materials are processed into magnesium oxide powder and zinc oxide powder, respectively, as direct reaction raw materials in oxide form. Then, the magnesium oxide powder, zinc oxide powder, and aluminum powder are mixed and pressed into pellets. The pellets are placed under vacuum conditions for simultaneous aluminothermic reduction, with the vacuum level set at 0.01 Pa to 10 Pa and the temperature at 700℃ to 1250℃. In this single reduction process, the aluminum powder simultaneously reduces magnesium oxide and zinc oxide, generating magnesium vapor and zinc vapor. The two metal vapors are alloyed under gaseous conditions and then condense to form a uniformly composed crude magnesium-zinc alloy, thus avoiding the volatilization and burn-off problems of zinc in traditional smelting methods and ensuring the uniformity of the alloy composition. At the same time, the solid product remaining after simultaneous aluminothermic reduction is the reduction slag, which contains oxides of magnesium, zinc, and aluminum. The reduction slag is then subjected to high-temperature calcination or melting treatment, causing the magnesium oxide, zinc oxide, and aluminum oxide to react and generate magnesium-zinc-aluminum spinel byproducts. Attached Figure Description

[0017] 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.

[0018] 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.

[0019] Figure 1 A schematic flowchart illustrating a method for preparing magnesium-zinc alloy and magnesium-zinc-aluminum spinel by simultaneous aluminothermic reduction, provided for embodiments of this application; Figure 2 This is a schematic diagram of the structure of a vacuum reduction device with a condenser crystallizer provided in an embodiment of this application; Figure label: 1-Vacuum reduction furnace; 2-Heating device; 3-Colder; 4-Cooling device; 5-Vacuum gauge; 6-Vacuum pumping device; 7-Pellet; 8-Connecting device. Detailed Implementation

[0020] 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.

[0021] The range descriptions used herein, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "including" and "contains" as used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships mentioned herein, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained through commercial purchase or prepared using existing methods.

[0022] Figure 1 This is a schematic flowchart illustrating a method for preparing magnesium-zinc alloy and magnesium-zinc-aluminum spinel by simultaneous aluminothermic reduction, as provided in an embodiment of this application.

[0023] like Figure 1 As shown in the embodiments of this application, a method for preparing magnesium-zinc alloy and magnesium-zinc-aluminum spinel by simultaneous aluminothermic reduction is provided, the method comprising: S1. The magnesium source raw material and the zinc source raw material are processed separately to obtain magnesium oxide powder and zinc oxide powder; S2. Based on the chemical composition of the target magnesium-zinc alloy, the magnesium oxide powder, the zinc oxide powder, and the aluminum powder are mixed to obtain a mixture; S3. Press the mixture to obtain pellets; S4. Under set temperature and set vacuum conditions, the pellets are subjected to simultaneous aluminothermic reduction so that magnesium oxide and zinc oxide in the pellets are simultaneously reduced by aluminum to generate magnesium vapor and zinc vapor. The magnesium vapor and the zinc vapor are alloyed under gaseous conditions and condensed to form crude magnesium-zinc alloy. The set temperature is 700℃~1250℃ and the set vacuum degree is 0.01Pa~10Pa. S5. The reduction slag after synchronous aluminothermic reduction is subjected to high-temperature calcination or melting treatment to obtain magnesium zinc aluminum spinel by-product.

[0024] In some embodiments, the method further includes: S6. Under a protective atmosphere or covering agent conditions, the crude magnesium-zinc alloy is smelted, refined, and cast to obtain a magnesium-zinc alloy ingot; the smelting temperature is 400℃~800℃, the covering agent includes at least one of chloride salts and fluoride salts, and the total mass fraction of impurity elements in the magnesium-zinc alloy ingot is ≤0.5%.

[0025] In some embodiments, the magnesium source material includes at least one selected from magnesium oxide, magnesite, dolomite, magnesium hydroxide, basic magnesium carbonate, magnesium chloride, and magnesium sulfate.

[0026] In some embodiments, the zinc source material includes at least one of zinc oxide, smithsonite, basic zinc carbonate, zinc hydroxide, zinc sulfate, and zinc chloride.

[0027] It should be noted that step S1 (raw material processing) converts the magnesium source material and zinc source material into magnesium oxide powder and zinc oxide powder, respectively. The magnesium source material can be magnesite, dolomite, magnesium hydroxide, basic magnesium carbonate, etc., and the zinc source material can be zinc oxide, smithsonite, basic zinc carbonate, etc. Through calcination or decomposition treatment, they exist in the form of oxide powder, providing highly active reactants for subsequent aluminothermic reduction.

[0028] Step S2 (Mixing and Batching): Based on the zinc content requirements of the target magnesium-zinc alloy, accurately weigh and mix magnesium oxide powder, zinc oxide powder, and aluminum powder to ensure the controllability of the alloy composition. The amount of aluminum powder added, acting as a reducing agent, must be calculated based on the stoichiometric ratio required for the complete reduction of magnesium oxide and zinc oxide.

[0029] Step S3 (pressing) involves pressing the mixed powder into pellets with a certain strength and size, increasing the contact area between reactants, which is beneficial for the smooth escape of gaseous products and the uniformity of the reaction during vacuum reduction.

[0030] Step S4 (Simultaneous Aluminothermic Reduction) is the core process of the entire method. Its function is to simultaneously reduce magnesium oxide and zinc oxide in the pellets with aluminum under vacuum and high temperature conditions, generating magnesium vapor and zinc vapor respectively. The two vapors are fully mixed in the gas phase and alloyed, and then condensed in a condenser to form a crude magnesium-zinc alloy. The main chemical reactions occurring during the simultaneous aluminothermic reduction process include: 2Al + 3MgO → Al₂O₃ + 3Mg(g), 2Al + 3ZnO → Al₂O₃ + 3Zn(g), 2Al + MgO + 3ZnO → MgAl₂O₄ + 3Zn(g), 2Al + 4ZnO → ZnAl₂O₄ + 3Zn(g), 2Al + 4MgO + 4ZnO → (Mg,Zn)Al₂O₄ + 3Mg(g) + 3Zn(g).

[0031] Step S4 involves two key process parameters: First, the vacuum level is set to 0.01 Pa to 10 Pa. Within this high vacuum range, the evaporation temperature of magnesium and zinc can be significantly reduced, promoting the reduction reaction towards the generation of metal vapor, while preventing the metal vapor from being oxidized and accelerating the vapor's transport to the condensation zone. Second, the temperature is set to 700℃ to 1250℃. Within this temperature range, the aluminothermic reduction reaction can proceed spontaneously and at a relatively fast rate, while ensuring efficient volatilization of magnesium and zinc in vapor form. Higher temperatures result in a more complete reaction, but this range also considers equipment tolerance and energy consumption, meeting the preparation requirements of alloys with different zinc contents. For example, the simultaneous aluminothermic reduction temperature can be set to 700℃, 780℃, 860℃, 940℃, 1020℃, 1100℃, 1180℃, 1250℃, etc., and the vacuum level can be set to 0.01 Pa, 1.43 Pa, 2.86 Pa, 4.29 Pa, 5.72 Pa, 7.15 Pa, 8.58 Pa, 10 Pa, etc.

[0032] Step S5 (Reduction Slag Treatment) involves calcining or melting the solid slag remaining after simultaneous aluminothermic reduction (mainly containing alumina and unreacted oxides) at high temperature to transform it into magnesium zinc aluminum spinel (MgO). ZnO Al2O3 ternary spinel system) enables high-value utilization of by-products and improves the comprehensive utilization rate of resources.

[0033] Step S6 involves purifying and homogenizing the crude magnesium-zinc alloy obtained from condensation. Melting and refining are carried out under a protective atmosphere or covering agent (such as chloride salts, fluoride salts, or their complexes) at a melting temperature of 400℃ to 800℃. This temperature range is higher than the melting point of the magnesium-zinc alloy but lower than the boiling point of zinc, effectively preventing zinc burn-off and promoting the separation of impurities from the melt. Finally, a magnesium-zinc alloy ingot is cast. The total mass fraction of impurity elements (such as Al, Fe, Si, Ni, Mn, etc.) in the resulting ingot is ≤0.5%, indicating that the magnesium-zinc alloy prepared by this method has high purity, meeting the purity requirements of most application fields. For example, the melting temperature of the crude magnesium-zinc alloy can be 400℃, 457℃, 514℃, 571℃, 628℃, 685℃, 742℃, 800℃, etc.

[0034] In some embodiments, the target magnesium-zinc alloy contains 0.5% to 50% zinc by mass.

[0035] The target magnesium-zinc alloy is limited to a zinc mass fraction of 0.5% to 50%, covering a wide range from low to high zinc content. This range can meet the diverse requirements of different applications for the mechanical properties, corrosion resistance, and biocompatibility of magnesium-zinc alloys. Zinc, as a major alloying element in magnesium alloys, directly affects the solid solution strengthening effect and precipitated phase characteristics. A low zinc content of 0.5% is suitable for applications requiring high plasticity, while a high zinc content of 50% imparts higher strength and unique corrosion behavior. This method achieves precise control of the composition within this wide range through vapor phase alloying. For example, the zinc mass fraction in the target magnesium-zinc alloy can be 0.5%, 7%, 14%, 21%, 28%, 35%, 42%, 50%, etc.

[0036] In some embodiments, the amount of aluminum powder added is 1.0 to 1.5 times the theoretical amount of aluminum powder to be added, where the theoretical amount of aluminum powder to be added is the mass of aluminum powder required for the complete reduction of magnesium oxide and zinc oxide.

[0037] The amount of aluminum powder added is limited to 1.0 to 1.5 times the theoretical amount. Using excess aluminum powder (1.0 to 1.5 times) ensures that magnesium oxide and zinc oxide are fully reduced, improves the reduction rate of magnesium and zinc, and avoids the retention of some oxides in the reduction slag due to insufficient reducing agent, thereby ensuring the alloy yield and compositional stability. For example, the multiple of aluminum powder added can be 1.0 times, 1.07 times, 1.14 times, 1.21 times, 1.28 times, 1.35 times, 1.42 times, 1.5 times, etc.

[0038] In some embodiments, the pressing is performed using a double-roller briquetting machine, the pressing pressure is 50MPa to 300MPa, and the pressing roller speed is 3r / min to 30r / min.

[0039] The pressing pressure is limited to 50 MPa to 300 MPa, and the roller speed is 3 r / min to 30 r / min. The pressing pressure and roller speed together determine the density and mechanical strength of the pellets. The pressure range of 50–300 MPa is suitable for different types of powder systems; lower pressure is suitable for easily moldable materials, while higher pressure yields denser pellets, helping to maintain the structural integrity of the pellets under vacuum and high temperature, preventing collapse from affecting the vapor escape channels. The roller speed of 3–30 r / min ensures uniform pressure transmission, resulting in a consistent density distribution within the pellets, which is beneficial for the uniform progress of the reduction reaction. For example, the pellet pressing pressure can be 50MPa, 85.7MPa, 121.4MPa, 157.1MPa, 192.8MPa, 228.5MPa, 264.2MPa, 300MPa, etc., and the pressing roller speed can be 3r / min, 5r / min, 10r / min, 15r / min, 18r / min, 21r / min, 25r / min, 30r / min, etc.

[0040] In some embodiments, the reaction time for the simultaneous aluminothermic reduction is 0.5 h to 6 h.

[0041] The reaction time for simultaneous aluminothermic reduction is limited to 0.5 h to 6 h. The reaction time, along with temperature and vacuum level, works synergistically to determine the extent of the reduction reaction. 0.5 h is suitable for rapid reactions of small batches or highly reactive raw materials, while 6 h can meet the requirements for sufficient reaction in large batches of pellets or materials that are difficult to reduce. Under given temperature (700–1250 °C) and vacuum level (0.01–10 Pa), this time range ensures that the reaction of magnesium oxide and zinc oxide being reduced by aluminum to generate magnesium vapor and zinc vapor tends to be complete, while avoiding energy waste caused by excessively long reaction times. For example, the reaction time for simultaneous aluminothermic reduction can be 0.5 h, 1.2 h, 2.0 h, 2.8 h, 3.6 h, 4.4 h, 5.2 h, 6 h, etc.

[0042] In some embodiments, the magnesium zinc aluminum spinel byproduct is a ternary spinel system of MgO-ZnO-Al2O3.

[0043] The magnesium-zinc-aluminum spinel byproduct is a ternary spinel system of MgO-ZnO-Al2O3. The formation of this system indicates that the magnesium, zinc, and aluminum oxides in the reducing slag underwent solid-phase or melting reactions during high-temperature treatment, generating a composite oxide with a spinel structure. Compared to simple binary spinels, the zinc and magnesium ions in the ternary spinel system can substitute for each other to form a continuous solid solution, endowing the byproduct with superior thermal stability, chemical inertness, and optical properties. Recovering it as a byproduct not only avoids the emission of solid waste but also allows it to be used in refractory materials, ceramic pigments, or catalyst supports, achieving high-value utilization of resources.

[0044] Figure 2 This is a schematic diagram of the structure of a vacuum reduction device with a condenser crystallizer provided in an embodiment of this application.

[0045] In some implementations, such as Figure 2 As shown, the synchronous aluminothermic reduction employs a vacuum reduction device with a condenser crystallizer, the device comprising: Vacuum reduction furnace; A heating device is used to heat the vacuum reduction furnace; The condenser crystallizer is connected to the vacuum reduction furnace via a connecting device; A cooling device is used to cool the condenser crystallizer; The pellets are placed inside the vacuum reduction furnace.

[0046] This application achieves the synergistic preparation of magnesium-zinc alloy and magnesium-zinc-aluminum spinel through an integrated process of simultaneous aluminothermic reduction, gas-state alloying, and byproduct conversion. The core of this process involves using magnesium oxide and zinc oxide as raw materials, and aluminum powder as a reducing agent. The mixture is pressed into pellets and placed in a vacuum reduction apparatus for simultaneous aluminothermic reduction at a vacuum of 0.01–10 Pa and a high temperature of 700–1250 °C. During this process, magnesium oxide and zinc oxide are simultaneously reduced by aluminum, generating magnesium vapor and zinc vapor, respectively. These two metal vapors are thoroughly mixed and alloyed in the gas phase, and then condensed in a condenser to directly form a homogeneous crude magnesium-zinc alloy. This gas-state alloying method effectively avoids the problem of zinc volatilization and burn-off in traditional smelting methods, ensuring precise control over the alloy composition. Simultaneously, the solid slag produced by the reduction reaction (mainly containing alumina and a small amount of unreacted oxides) undergoes high-temperature calcination or melting treatment. The MgO, ZnO, and Al2O3 within this slag then undergo a solid-phase reaction or a melting reaction, generating a byproduct with a ternary spinel structure of MgO-ZnO-Al2O3. This byproduct and the alloy preparation are completed simultaneously in the same reduction process: the reduction process produces both metal vapor for alloy production and reducing slag for spinel production; the two processes do not interfere with each other but originate from the same source. Therefore, this application, through a single reduction operation, directs the magnesium, zinc, and aluminum elements in the raw materials to two high-value-added products, magnesium-zinc alloy and magnesium-zinc-aluminum spinel, respectively, achieving resource diversion and efficient utilization.

[0047] 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 standards / industry standards / the disclosure herein; if there are no corresponding national standards / industry standards / the disclosure herein, they are performed according to generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer.

[0048] Example 1 Magnesite was calcined at 900℃ for 3 hours to obtain lightly calcined magnesia powder; zinc oxide powder was used as the zinc source and no pretreatment was required. Magnesia powder, zinc oxide powder, and aluminum powder were mixed, with the zinc oxide addition corresponding to a zinc content of 3 wt.% in the target magnesium-zinc alloy, and the aluminum powder addition being 120% of the theoretical reduction amount. The mixture was pressed into pellets and placed in a vacuum reduction tank equipped with a condenser crystallizer, where it was reduced for 4 hours under a vacuum of 5 Pa and at 1100℃. The resulting crude magnesium-zinc alloy was obtained by condensation, refined by melting at 650℃, and then cast into ingots. The reduction slag was electrofused to obtain magnesium-zinc-aluminum spinel.

[0049] Example 2 Dolomite was calcined at 1000℃ for 2 hours to obtain calcined dolomite. The calcined dolomite was then digested with water, followed by carbonization and filtration to obtain heavy magnesium water. The heavy magnesium water was then pyrolyzed and calcined to obtain magnesium oxide powder. The zinc source was smithsonite, which was calcined at 600℃ for 2 hours to decompose it into zinc oxide powder. Magnesium oxide powder, zinc oxide powder, and aluminum powder were mixed, with the zinc oxide addition corresponding to a zinc content of 10 wt.% in the target magnesium-zinc alloy, and the aluminum powder addition being 125% of the theoretical reduction amount. The mixture was pressed into pellets and placed in a vacuum reduction tank equipped with a condenser crystallizer. Reduction was carried out at 3 Pa vacuum and 1000℃ for 5 hours. The resulting crude magnesium-zinc alloy was obtained by condensation, refined by melting at 700℃, and then cast into ingots. The reduction slag was then calcined at high temperature to obtain magnesium-zinc-aluminum spinel.

[0050] Example 3 Magnesium hydroxide was calcined at 800℃ for 1 hour to obtain lightly calcined magnesium oxide powder. Zinc hydroxide was used as the zinc source, and it was calcined at 500℃ for 1 hour to decompose it into zinc oxide powder. Using lightly calcined magnesium oxide as the magnesium source, the raw materials were prepared and pelletized according to the method in Example 1, wherein the amount of zinc oxide added corresponded to a zinc content of 25 wt.% in the target magnesium-zinc alloy, and the amount of aluminum powder added was 130% of the theoretical reduction amount. The reduction was carried out at a vacuum of 1 Pa and 1150℃ for 3 hours, and the crude magnesium-zinc alloy was obtained by condensation. After refining, magnesium-zinc alloy ingots were obtained, and magnesium-zinc-aluminum spinel was produced as a byproduct.

[0051] Example 4 Magnesium oxide powder was obtained by calcining basic magnesium carbonate. Zinc sulfate was used as the zinc source, and it was calcined at 700°C for 2 hours to decompose it into zinc oxide powder. Using magnesium oxide powder as the magnesium source, the raw materials were prepared and pelletized according to the method in Example 1. The amount of zinc oxide added corresponded to a zinc content of 40 wt.% in the target magnesium-zinc alloy, and the amount of aluminum powder added was 140% of the theoretical reduction amount. The reduction was carried out at a vacuum of 1 Pa and 1200°C for 6 hours. After condensation, crude magnesium-zinc alloy was obtained, which was then refined to obtain magnesium-zinc alloy ingots. Magnesium-zinc-aluminum spinel was produced as a byproduct.

[0052] Example 5 Magnesite was calcined at 900℃ for 3 hours to obtain lightly calcined magnesia powder; zinc oxide powder was used as the zinc source. Magnesia powder, zinc oxide powder, and aluminum powder were mixed, with the zinc oxide addition corresponding to a zinc content of 0.5 wt.% in the target magnesium-zinc alloy, and the aluminum powder addition being 100% of the theoretical reduction amount. The mixture was pressed into pellets under 50 MPa pressure and then placed in a vacuum reduction tank equipped with a condenser crystallizer, where it was reduced for 0.5 hours under a vacuum of 0.01 Pa and at 700℃. The resulting crude magnesium-zinc alloy was obtained through condensation and refining to obtain magnesium-zinc alloy ingots, with magnesium-zinc-aluminum spinel as a byproduct.

[0053] Example 6 Magnesium oxide powder was obtained by calcining basic magnesium carbonate at 900℃; zinc oxide powder was obtained by calcining basic zinc carbonate at 650℃. Magnesium oxide powder, zinc oxide powder, and aluminum powder were mixed, with the zinc oxide content corresponding to 50 wt.% of the zinc content in the target magnesium-zinc alloy, and the aluminum powder content being 150% of the theoretical reduction amount. The mixture was pressed into pellets under 200 MPa pressure and then placed in a vacuum reduction tank equipped with a condenser crystallizer, where it was reduced for 6 hours under a vacuum of 10 Pa and at 1250℃. Crude magnesium-zinc alloy was obtained by condensation and refining to obtain magnesium-zinc alloy ingots, with magnesium-zinc-aluminum spinel as a byproduct.

[0054] The composition of the magnesium-zinc alloy ingots obtained in Examples 1-6 was determined, and the results are shown in Table 1.

[0055] Table 1. Elemental content (wt.%) of magnesium-zinc alloys prepared in Examples 1-6

[0056] As shown in Table 1, the actual zinc content in the magnesium-zinc alloys prepared in Examples 1 to 6 all falls within the target range of 0.5% to 50%, and is basically consistent with the zinc content set in each example, indicating that this method can accurately control the alloy composition. Meanwhile, the total mass fraction of impurity elements in the alloys of each example is all no higher than 0.5%, indicating that the magnesium-zinc alloys prepared by this method have high purity and meet application requirements.

[0057] Furthermore, one or more technical solutions in the embodiments of this application have at least the following technical effects or advantages: (1) This application uses simultaneous aluminothermic reduction of magnesium oxide and zinc oxide to generate magnesium vapor and zinc vapor under vacuum conditions, and completes the alloying process under gaseous conditions. This avoids the problem of zinc burning during the traditional melt alloying process, which is beneficial to improving the zinc recovery rate and the stability of the alloy composition.

[0058] (2) This application uses a gas-state alloying-condensation crystallization method to prepare magnesium-zinc alloys, and the resulting alloys have uniform composition and high purity.

[0059] (3) The reduction residue of this application can be processed into magnesium zinc aluminum spinel after high temperature treatment, realizing the resource utilization of by-products and improving the resource utilization rate and economy of the process.

[0060] (4) The process of this application can directly utilize existing vacuum magnesium smelting equipment, which has strong equipment versatility and is easy to industrialize.

[0061] (5) The raw materials for this application are widely available. Magnesite, dolomite, basic magnesium carbonate, etc. can be used as magnesium sources, and zinc oxide, zinc carbonate and zinc-containing intermediate materials can also be used as zinc sources, making it highly adaptable.

[0062] 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 herein.

Claims

1. A method for preparing magnesium-zinc alloy and magnesium-zinc-aluminum spinel by simultaneous aluminothermic reduction, characterized in that, The method includes: Magnesium source raw materials and zinc source raw materials are processed separately to obtain magnesium oxide powder and zinc oxide powder; According to the chemical composition of the target magnesium-zinc alloy, the magnesium oxide powder, the zinc oxide powder, and the aluminum powder are mixed and formulated to obtain a mixture; The mixture is pressed to obtain pellets; Under set temperature and set vacuum conditions, the pellets are subjected to simultaneous aluminothermic reduction so that magnesium oxide and zinc oxide in the pellets are simultaneously reduced by aluminum to generate magnesium vapor and zinc vapor. The magnesium vapor and the zinc vapor are alloyed under gaseous conditions and condensed to form crude magnesium-zinc alloy. The set temperature is 700℃~1250℃ and the set vacuum degree is 0.01Pa~10Pa. The reduction slag after synchronous aluminothermic reduction is subjected to high-temperature calcination or melting treatment to obtain magnesium zinc aluminum spinel by-product.

2. The method according to claim 1, characterized in that, The method further includes: Under a protective atmosphere or covering agent conditions, the crude magnesium-zinc alloy is smelted, refined, and cast to obtain a magnesium-zinc alloy ingot; the smelting temperature is 400℃~800℃, the covering agent includes at least one of chloride salts and fluoride salts, and the total mass fraction of impurity elements in the magnesium-zinc alloy ingot is ≤0.5%.

3. The method according to claim 1, characterized in that, The magnesium source material includes at least one of the following: magnesium oxide, magnesite, dolomite, magnesium hydroxide, basic magnesium carbonate, magnesium chloride, and magnesium sulfate.

4. The method according to claim 1, characterized in that, The zinc source material includes at least one of zinc oxide, smithsonite, basic zinc carbonate, zinc hydroxide, zinc sulfate, and zinc chloride.

5. The method according to claim 1, characterized in that, The target magnesium-zinc alloy contains 0.5% to 50% zinc by mass.

6. The method according to claim 1, characterized in that, The amount of aluminum powder added is 1.0 to 1.5 times the theoretical amount of aluminum powder to be added, where the theoretical amount of aluminum powder to be added is the mass of aluminum powder required for the complete reduction of magnesium oxide and zinc oxide.

7. The method according to claim 1, characterized in that, The pressing is performed using a double-roller briquetting machine, with a pressing pressure of 50MPa to 300MPa and a pressing roller speed of 3r / min to 30r / min.

8. The method according to claim 1, characterized in that, The reaction time for the simultaneous aluminothermic reduction is 0.5h to 6h.

9. The method according to claim 1, characterized in that, The magnesium zinc aluminum spinel byproduct is a ternary spinel system of MgO-ZnO-Al2O3.

10. The method according to claim 1, characterized in that, The simultaneous aluminothermic reduction employs a vacuum reduction device with a condenser crystallizer, the device comprising: Vacuum reduction furnace (1); Heating device (2) is used to heat the vacuum reduction furnace (1); The condenser (3) is connected to the vacuum reduction furnace (1) via a connecting device (8); Cooling device (4) for cooling the condenser (3); The pellets are placed inside the vacuum reduction furnace (1).

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