A method for preparing iron-based alloy and magnetic high-entropy alloy by using iron-rich metallurgical slag
By treating iron-rich metallurgical slag with melting oxidation, magnetic separation, and coal-based reduction, iron-based alloys are prepared and magnetic high-entropy alloys are prepared by vacuum melting. This solves the problem of separating and recovering various valuable metals in nickel and copper slag, and realizes efficient resource utilization and environmental protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LANZHOU UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2023-06-16
- Publication Date
- 2026-07-10
AI Technical Summary
Valuable metal elements such as iron, nickel, cobalt and copper in nickel slag and copper slag are difficult to separate and recover effectively. Traditional methods cannot achieve the simultaneous enrichment of multiple metals, resulting in resource waste and environmental pollution.
Metallized pellets were prepared by mixing iron-rich metallurgical slag with CaO for melt oxidation, followed by magnetic separation and mixing with coal powder and pelletizing agent. Iron-based alloys were prepared by coal-based reduction and melting separation, and then magnetic high-entropy alloys were prepared by mixing with Ni, Co and Cu and vacuum melting.
It enables the efficient extraction and recycling of iron, nickel, cobalt and copper, improves resource utilization, reduces solid waste accumulation, reduces environmental pollution, and provides high-value magnetic alloy products.
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Figure CN116770059B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metallurgical slag resource utilization technology, specifically to a method for preparing iron-based alloys and magnetic high-entropy alloys using iron-rich metallurgical slag. Background Technology
[0002] Nickel slag and copper slag are industrial solid wastes with large production volumes in the metallurgical industry, mainly generated by pyrometallurgical processes. Large quantities of nickel and copper slag not only occupy land and pollute the environment but also result in a huge waste of resources. The TFe (total iron) content in nickel and copper slag exceeds 40%, and valuable metal elements such as Ni, Co, and Cu are also present. The main phase of iron in nickel and copper slag is fir olivine, existing as weakly magnetic fir olivine (2FeO·SiO2). Fir olivine is a eutectic composed of complex silicates, a complex network crystal with interconnected Si-O atoms, making effective Si-Fe separation difficult using traditional mineral processing methods. Furthermore, traditional reduction treatment methods for nickel and copper slag typically target a single metal element (e.g., iron) and cannot simultaneously enrich and extract valuable metals such as Ni, Co, and Cu. Summary of the Invention
[0003] In view of this, the purpose of this invention is to provide a method for preparing iron-based alloys and magnetic high-entropy alloys using iron-rich metallurgical slag. The method provided by this invention can achieve the co-enrichment and efficient extraction and recovery of Fe, Ni, Co and Cu in iron-rich metallurgical slag.
[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0005] This invention provides a method for preparing iron-based alloys using iron-rich metallurgical slag, comprising the following steps:
[0006] Iron-rich metallurgical slag is mixed with CaO, and after molten oxidation and first cooling, oxidized metallurgical slag is obtained.
[0007] The oxidized metallurgical slag is subjected to magnetic separation to obtain magnetite powder;
[0008] The magnetite powder, coal powder and pelletizing agent are mixed and then subjected to pelletizing, coal-based reduction and second cooling in sequence to obtain metallized pellets.
[0009] The metallized pellets are subjected to melting and separation treatment to obtain an iron-based alloy.
[0010] Preferably, the iron-rich metallurgical slag includes nickel slag and / or copper slag; the nickel slag comprises the following components in weight percentage: TFe 30-50%, SiO2 30-50%, MgO 1-15%, CaO 1.5-5%, Al2O3 2.5-6%, Ni 0.3-0.6%, Co 0.05-0.1%, Cu 0.2-0.4%;
[0011] The copper slag comprises the following components by mass percentage: TFe 40-60%, Cu 0.5%-6%, SiO2 20-40%, MgO 1-8%, CaO 1-20%, Ni <0.1%, and Co <0.1%.
[0012] Preferably, the mass ratio of the iron-rich metallurgical slag to CaO is 1:0.08 to 0.25;
[0013] The melting oxidation temperature is 1350–1500℃, and the holding time is 30–60 min;
[0014] The cooling rate of the first cooling is 5 to 10 °C / min.
[0015] Preferably, the magnetic separation conditions include: a magnetic field strength of 100-300 mT, the use of the oxidized metallurgical slag in the form of an oxidized metallurgical slag aqueous suspension, and a flow rate of 1-2 L / min for the oxidized metallurgical slag aqueous suspension.
[0016] Preferably, the pelletizing agent comprises sodium carbonate and bentonite; the mass ratio of sodium carbonate to bentonite is 1:1 to 4;
[0017] The mass ratio of magnetite powder, coal powder, and pelletizing agent is 1:0.25-0.4:0.03-0.06;
[0018] The diameter of the magnetite pellets obtained by pelletizing is 12-18 mm;
[0019] The coal-based reduction temperature is 1150–1350℃, and the holding time is 30–60 min;
[0020] The second cooling rate is 30–100 °C / min, and the second cooling is carried out under air-isolated conditions.
[0021] Preferably, the melting treatment temperature is 1550–1750°C, and the holding time is 40–120 min.
[0022] The present invention provides an iron-based alloy prepared by the method described in the above technical solution, comprising the following components in mass percentage: Fe 90-99%, Ni 0.01-1%, Co 0.01-0.35%, Cu 0.5-8%.
[0023] This invention provides a method for preparing a magnetic high-entropy alloy, comprising the following steps:
[0024] The iron-based alloy, Ni, Co and Cu described in the above technical solution are mixed, and the resulting mixture is vacuum melted to obtain a magnetic high-entropy alloy. The molar ratio of Fe, Ni, Co and Cu in the mixture is 1:1:1:0.4 to 1.
[0025] Preferably, the vacuum melting temperature is 1600–2000℃, the holding time is 10–60 min, and the vacuum degree is 3×10⁻⁶. -3 ~5×10 -3 Pa.
[0026] This invention provides a magnetic high-entropy alloy prepared by the preparation method described in the above technical solution.
[0027] This invention reconstructs the iron-containing phases in iron-rich metallurgical slag through high-temperature mineral phase reconstruction via melt oxidation, transforming Fe, Ni, Co, and Cu elements into the (Fe,Ni,Co,Cu)Fe₂O₄ magnetite phase. The magnetite is then extracted and recovered via magnetic separation. Finally, an iron-based alloy is prepared using a coal-based direct reduction-melting process. This method achieves the co-enrichment and efficient extraction and recovery of Fe, Ni, Co, and Cu from iron-rich metallurgical slag, with high recovery rates for these elements. The resulting iron-based alloy has low impurity content and high quality, realizing the extraction and high-value reuse of valuable metal elements from iron-rich metallurgical slag. This significantly enhances the economic value of iron-rich metallurgical slag and has a significant impact on the sustainable development of copper and nickel smelting enterprises. Simultaneously, it reduces the accumulation of industrial solid waste from iron-rich metallurgical slag, thus reducing its environmental pollution. Furthermore, the method provided by this invention is simple to operate, low in cost, and suitable for industrial production.
[0028] This invention involves vacuum melting the iron-based alloy with Ni, Co, and Cu to obtain a magnetic high-entropy alloy, thereby realizing the high-value reuse of Fe, Ni, Co, and Cu elements in iron-rich metallurgical slag, which has high economic value. Attached Figure Description
[0029] Figure 1 Hysteresis loop diagram of the magnetic high-entropy alloy prepared in Example 1;
[0030] Figure 2 Hysteresis loop diagram of the magnetic high-entropy alloy prepared in Example 2;
[0031] Figure 3 Hysteresis loop diagram of the magnetic high-entropy alloy prepared in Example 3;
[0032] Figure 4Hysteresis loop diagram of the magnetic high-entropy alloy prepared in Example 4;
[0033] Figure 5 Hysteresis loop diagram of the magnetic high-entropy alloy prepared in Example 5;
[0034] Figure 6 The image shows the hysteresis loop of the high-entropy magnetic alloy prepared in Example 6. Detailed Implementation
[0035] This invention provides a method for preparing iron-based alloys using iron-rich metallurgical slag, comprising the following steps:
[0036] Iron-rich metallurgical slag is mixed with CaO, and after molten oxidation and first cooling, oxidized metallurgical slag is obtained.
[0037] The oxidized metallurgical slag is subjected to magnetic separation to obtain magnetite powder;
[0038] The magnetite powder, coal powder and pelletizing agent are mixed and then subjected to pelletizing, coal-based reduction and second cooling in sequence to obtain metallized pellets.
[0039] The metallized pellets are subjected to melting and separation treatment to obtain an iron-based alloy.
[0040] Unless otherwise specified, all raw materials used in this invention are commercially available products.
[0041] This invention involves mixing iron-rich metallurgical slag with CaO, followed by molten oxidation and a first cooling process to obtain oxidized metallurgical slag.
[0042] In this invention, the iron-rich metallurgical slag preferably comprises nickel slag and / or copper slag. In this invention, the nickel slag preferably comprises the following components by mass percentage: TFe (total iron) 30-50%, SiO2 30-50%, MgO 1-15%, CaO 1.5-5%, Al2O3 2.5-6%, Ni 0.3-0.6%, Co 0.05-0.1%, Cu 0.2-0.4%. In this invention, the copper slag preferably comprises the following components by mass percentage: TFe 40-60%, Cu 0.5%-6%, SiO2 20-40%, MgO 1-8%, CaO 1-20%, Ni <0.1%, Co <0.1%. In this invention, the iron-rich metallurgical slag is preferably crushed and then sieved before use. This invention does not specifically limit the crushing method; any crushing method well known to those skilled in the art can be used. In this invention, the preferred sieve mesh size is 200 mesh, and the undersize portion is taken as iron-rich metallurgical slag powder (particle size ≤ 200 mesh) and mixed with CaO.
[0043] In this invention, the mass ratio of the iron-rich metallurgical slag to CaO is preferably 1:0.08-0.25, more preferably 1:0.09-0.2, and even more preferably 1:0.09-0.15. In this invention, the purity of the CaO is preferably analytical grade.
[0044] The present invention does not have any special limitations on the mixing method, and any mixing method known to those skilled in the art can be used, such as stirring.
[0045] After the mixing is completed, the present invention preferably further includes pressing the obtained metallurgical slag mixture into tablets to obtain modified metallurgical slag tablets. In the present invention, the pressing pressure is preferably 15-25 MPa, more preferably 20 MPa; the pressing time is 15-30 s, more preferably 20-25 s; and the pressing temperature is preferably room temperature.
[0046] In this invention, the temperature of the melt oxidation is preferably 1350–1500°C, more preferably 1400–1500°C, and even more preferably 1450–1500°C; the heating rate from room temperature to the temperature of the melt oxidation is preferably 5–10°C / min, more preferably 5–8°C / min; the holding time of the melt oxidation is preferably 30–60 min, more preferably 40–60 min, and even more preferably 50–60 min; and the atmosphere of the melt oxidation is preferably air.
[0047] In this invention, the cooling rate of the first cooling is preferably 5 to 10 °C / min, more preferably 5 to 8 °C / min, and even more preferably 5 to 6 °C / min.
[0048] After the first cooling, the present invention preferably further includes crushing and sieving the obtained roasted and cooled material to obtain oxidized metallurgical slag. The present invention does not have a particular limitation on the crushing method; any crushing method well known to those skilled in the art can be used. In the present invention, the screen mesh size is preferably 200 mesh, and the oxidized metallurgical slag (particle size ≤ 200 mesh) below the screen is taken for subsequent magnetic separation.
[0049] After obtaining the oxidized metallurgical slag, the present invention performs magnetic separation on the oxidized metallurgical slag to obtain magnetite powder.
[0050] In this invention, the conditions for magnetic separation include: the magnetic field strength is preferably 100-300 mT, more preferably 150-250 mT, and even more preferably 200 mT; the oxidized metallurgical slag used in the magnetic separation process is preferably used in the form of an oxidized metallurgical slag aqueous suspension, the flow rate of the oxidized metallurgical slag aqueous suspension is preferably 1-2 L / min, more preferably 1.5 L / min; the concentration of the oxidized metallurgical slag aqueous suspension is preferably 50-150 g / L, more preferably 50-100 g / L; and the magnetic separation is preferably carried out in a magnetic separator.
[0051] After obtaining magnetite powder, the present invention mixes the magnetite powder, coal powder and pelletizing agent, and performs pelletizing, coal-based reduction and second cooling in sequence to obtain metallized pellets.
[0052] In this invention, the pelletizing agent preferably comprises sodium carbonate and bentonite; the mass ratio of sodium carbonate to bentonite is preferably 1:1 to 4, more preferably 1:1 to 3, and even more preferably 1:1 to 2. In this invention, sodium carbonate and bentonite are used as pelletizing agents, and sodium carbonate preferentially generates a liquid phase during subsequent processing, reducing the pressure of solid phase expansion. In this invention, the mass ratio of magnetite powder, coal powder, and pelletizing agent is preferably 1:0.25 to 0.4:0.03 to 0.06, more preferably 1:0.3 to 0.4:0.04 to 0.05. In this invention, the coal powder is preferably high-volatile coal powder, and the air-dried basis (i.e., the composition of the coal powder after vacuum drying) moisture content is preferably 3 to 10%, the air-dried basis ash content is preferably 3 to 10%, the air-dried basis volatile matter is preferably >40%, and the air-dried basis fixed carbon is preferably <50%; the particle size of the coal powder is preferably ≤200 mesh (74 μm).
[0053] The present invention does not have any special limitations on the pelletizing process. Any pelletizing operation known to those skilled in the art can be used to obtain magnetite pellets with a diameter of 12 to 18 mm.
[0054] In this invention, the temperature for coal-based reduction is preferably 1150–1350°C, more preferably 1200–1350°C, and even more preferably 1250–1300°C; the heating rate from room temperature to the coal-based reduction temperature is preferably 5–10°C / min, more preferably 5–8°C / min; the holding time for coal-based reduction is preferably 30–60 min, more preferably 40–60 min, and even more preferably 50–60 min; the atmosphere for coal-based reduction is preferably a protective atmosphere, which preferably includes nitrogen, argon, or helium.
[0055] In this invention, the cooling rate of the second cooling is preferably 30–100°C / min, more preferably 40–80°C / min, and even more preferably 50–60°C / min; the second cooling is preferably carried out under air-isolated conditions. The rapid cooling under the above conditions effectively prevents the oxidation of reduced iron.
[0056] After obtaining the metallized pellets, the present invention performs a melting and separation treatment on the metallized pellets to obtain an iron-based alloy. In the present invention, the temperature of the melting and separation treatment is preferably 1550-1750℃, more preferably 1600-1750℃, and even more preferably 1650-1700℃; the holding time of the melting and separation treatment is preferably 40-120 min, more preferably 50-100 min, and even more preferably 60-80 min.
[0057] The present invention provides an iron-based alloy prepared by the method described in the above technical solution, comprising the following components in mass percentage: Fe 90-99%, Ni 0.01-1%, Co 0.01-0.25%, Cu 0.5-8%.
[0058] In this invention, when nickel slag is used as raw material, the iron-based alloy comprises the following components in mass percentage: Fe is preferably 94-99%, more preferably 97-99%; Ni is preferably 0.7-0.9%, more preferably 0.8-0.9%; Co is preferably 0.15-0.35%, more preferably 0.2-0.32%; and Cu is preferably 0.5-1%, more preferably 0.5-0.8%.
[0059] In this invention, when copper slag is used as raw material, the iron-based alloy comprises the following components in mass percentage: Fe is preferably 90-94%, more preferably 91-93%; Ni is preferably 0.01-0.1%, more preferably 0.01-0.05%; Co is preferably 0.01-0.1%, more preferably 0.01-0.05%; and Cu is preferably 4-8%, more preferably 6-8%.
[0060] This invention provides a method for preparing a magnetic high-entropy alloy, comprising the following steps:
[0061] The iron-based alloy, Ni, Co, and Cu described in the above technical solution are mixed to obtain a mixture; the molar ratio of Fe, Ni, Co, and Cu in the mixture is 1:1:1:0.4 to 1.
[0062] The mixture is vacuum melted to obtain a magnetic high-entropy alloy.
[0063] This invention mixes the iron-based alloy, Ni, Co, and Cu described in the above technical solution to obtain a mixture. In this invention, the molar ratio of Fe, Ni, Co, and Cu in the mixture is 1:1:1:0.4 to 1, preferably 1:1:1:0.4 to 0.8, and more preferably 1:1:1:0.4 to 0.6. This invention does not impose any particular limitation on the mixing process; any mixing method well-known to those skilled in the art that can achieve uniform mixing of the raw materials is acceptable, such as stirring. In this invention, the purity of Ni, Co, and Cu is preferably >99%, and the particle size is preferably ≤200 mesh.
[0064] After obtaining the mixture, the present invention performs vacuum melting on the mixture to obtain a magnetic high-entropy alloy. In the present invention, the vacuum melting temperature is preferably 1600–2000℃, more preferably 1700–1900℃, and even more preferably 1800℃; the holding time of the vacuum melting is preferably 10–60 min, more preferably 20–50 min, and even more preferably 30–40 min; the vacuum degree of the vacuum melting is preferably 3 × 10⁻⁶. -3 ~5×10 -3 Pa, more preferably 4 × 10 Pa -3 ~5×10 -3 Pa, further 4.5 × 10 -3 ~5×10 -3 Pa; the vacuum melting is preferably carried out in a vacuum melting furnace.
[0065] This invention provides a magnetic high-entropy alloy prepared by the method described above. In this invention, the preferred chemical composition of the magnetic high-entropy alloy is (FeNiCo). 100-x Cu x Where x represents a mass percentage (%), x is preferably 10-30, more preferably 10-20, and even more preferably 10-15; the chemical composition of the magnetic high-entropy alloy is preferably Fe 24.9 Ni 26.2 Co 26.2 Cu 22.7 Fe 26.3 Ni 27.8 Co 27.8 Cu 18.1 or Fe 28.1 Ni 29.6 Co 29.6 Cu 12.8 .
[0066] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0067] In the following examples, the nickel slag, specifically flash furnace water-quenched nickel slag, has the following main components: TFe 36.74%, SiO2 34.78%, MgO 9.93%, CaO 1.18%, Ni 0.38%, Co 0.10%, and Cu 0.28%. The main phases are fir olivine, ferromagnesian olivine, and a glassy phase. The copper slag has the following composition: TFe content 41.55%, iron mainly present as fir olivine (Fe2SiO4) and magnetite (Fe3O4), Cu (elemental) 4.25%, copper mainly present as matte (Cu2S), SiO2 26.82%, MgO 1.42%, CaO 3.29%, and Ni and Co contents both less than 0.1%. The CaO purity is analytical grade. High volatile matter coal powder: air-dried basis moisture 3-10%, air-dried basis ash 3-10%, air-dried basis volatile matter >40%, air-dried basis fixed carbon <50%, particle size ≤74μm. Ni powder, Co powder and Cu powder all have a purity >99% and a particle size ≤74μm.
[0068] Example 1
[0069] (1) After crushing the nickel slag, sieve it through a 200-mesh screen. Take 80g of the nickel slag powder that is below the screen and mix it evenly with 7.81g of CaO. Compress the mixture into tablets for 25s at room temperature and 20MPa. Place the resulting modified nickel slag tablets in a corundum crucible and heat them to 1500℃ in a muffle furnace at a heating rate of 5℃ / min. Hold the temperature for 60min to melt and oxidize. Then cool them to room temperature at a rate of 5℃ / min and crush them to below 200 mesh. Place the oxidized metallurgical slag (powder) aqueous suspension (concentration of 100g / L) into a magnetic separator at a flow rate of 1.5L / min and perform magnetic separation at 200mT to obtain magnetite powder. The magnetite powder, coal powder, bentonite, and sodium carbonate were mixed in a mass ratio of 1:0.4:0.02:0.02 and pelletized. The resulting magnetite pellets with a diameter of 12–18 mm were vacuum dried at 80 °C for 6 h to constant weight. They were then placed in a graphite crucible and heated to 1300 °C in a vertical tube furnace under a nitrogen atmosphere at a heating rate of 5 °C / min. The mixture was then held at this temperature for 60 min for coal-based reduction and cooled to room temperature at a rate of 80 °C / min under air-isolated conditions to obtain metallized pellets. These metallized pellets were placed in an electric furnace and held at 1700 °C for 60 min, then cooled to room temperature to obtain an iron-based alloy. The contents of Fe, Ni, Co, and Cu in the iron-based alloy were determined using X-ray fluorescence spectrometry (XRF) and inductively coupled plasma atomic emission spectrometry (ICP), as shown in Table 1.
[0070] Table 1. Main chemical composition of iron-based alloys recovered from nickel slag.
[0071] element Fe Ni Co Cu Content / wt% 97.82 0.88 0.24 0.56
[0072] (2) The iron-based alloy is mixed evenly with Ni powder, Co powder and Cu powder. The resulting mixture (Fe:Ni:Co:Cu molar ratio = 1:1:1:0.8) is placed in a vacuum melting furnace and heated at 1800℃ and 5×10⁻⁶ °C. -3 Under Pa conditions, vacuum melting for 30 min yields a magnetic high-entropy alloy (Fe). 24.9 Ni 26.2 Co 26.2 Cu 22.7 The magnetic properties of the high-entropy magnetic alloy were characterized using a vibrating magnetometer (VSM), and the results are as follows: Figure 1 As shown, by Figure 1 It can be seen that the saturation magnetization of the magnetic high-entropy alloy is 85 emu / g, indicating excellent magnetic properties.
[0073] Example 2
[0074] (1) After crushing the nickel slag, sieve it through a 200-mesh screen. Take 80g of the nickel slag powder that is below the screen and mix it evenly with 7.81g of CaO. Compress the mixture into tablets for 25s at room temperature and 20MPa. Place the resulting modified nickel slag tablets in a corundum crucible and heat them to 1450℃ in a muffle furnace at a heating rate of 5℃ / min. Hold the temperature for melting and oxidation for 60min. Then cool them to room temperature at a rate of 5℃ / min and crush them to below 200 mesh. Place the oxidized metallurgical slag (powder) aqueous suspension (concentration of 100g / L) into a magnetic separator at a flow rate of 1.5L / min and perform magnetic separation at 200mT to obtain magnetite powder. The magnetite powder, coal powder, bentonite, and sodium carbonate were mixed in a mass ratio of 1:0.4:0.02:0.02 and pelletized. The resulting magnetite pellets with a diameter of 12–18 mm were vacuum dried at 80 °C for 6 hours to constant weight. They were then placed in a graphite crucible and heated to 1300 °C in a vertical tube furnace under a nitrogen atmosphere at a heating rate of 5 °C / min. The mixture was then held at this temperature for 60 minutes for coal-based reduction and cooled to room temperature at a rate of 80 °C / min under air-isolated conditions to obtain metallized pellets. These metallized pellets were placed in an electric furnace and held at 1700 °C for 60 minutes, then cooled to room temperature to obtain an iron-based alloy. The contents of Fe, Ni, Co, and Cu in the iron-based alloy were determined using X-ray fluorescence spectrometry (XRF) and inductively coupled plasma atomic emission spectrometry (ICP), as shown in Table 2.
[0075] Table 2. Main chemical components of iron-based alloys recovered from nickel slag.
[0076] element Fe Ni Co Cu Content / wt% 97.70 0.94 0.28 0.58
[0077] (2) The iron-based alloy is mixed evenly with Ni powder, Co powder and Cu powder. The resulting mixture (Fe:Ni:Co:Cu molar ratio = 1:1:1:0.6) is placed in a vacuum melting furnace and heated at 1800℃ and 5×10⁻⁶ °C. -3 Under Pa conditions, vacuum melting for 30 min yields a magnetic high-entropy alloy (Fe). 26.3 Ni 27.8 Co 27.8 Cu 18.1 The magnetic properties of the high-entropy magnetic alloy were characterized using a vibrating magnetometer (VSM), and the results are as follows: Figure 2 As shown, by Figure 2 It can be seen that the saturation magnetization of the magnetic high-entropy alloy is 94 emu / g, indicating excellent magnetic properties.
[0078] Example 3
[0079] (1) After crushing the nickel slag, sieve it through a 200-mesh screen. Take 80g of the nickel slag powder that is below the screen and mix it evenly with 7.81g of CaO. Compress the mixture into tablets for 25s at room temperature and 20MPa. Place the resulting modified nickel slag tablets in a corundum crucible and heat them to 1400℃ in a muffle furnace at a heating rate of 5℃ / min. Hold the temperature for melting and oxidation for 60min. Then cool them to room temperature at a rate of 5℃ / min and crush them to below 200 mesh. Place the oxidized metallurgical slag (powder) aqueous suspension (concentration of 100g / L) into a magnetic separator at a flow rate of 1.5L / min and perform magnetic separation at 200mT to obtain magnetite powder. The magnetite powder, coal powder, bentonite, and sodium carbonate were mixed in a mass ratio of 1:0.4:0.02:0.02 and pelletized. The resulting magnetite pellets with a diameter of 12–18 mm were vacuum dried at 80 °C for 6 h to constant weight. They were then placed in a graphite crucible and heated to 1300 °C in a vertical tube furnace under a nitrogen atmosphere at a heating rate of 5 °C / min. The mixture was then held at this temperature for 60 min for coal-based reduction and cooled to room temperature at a rate of 80 °C / min under air-isolated conditions to obtain metallized pellets. These metallized pellets were placed in an electric furnace and held at 1700 °C for 60 min, then cooled to room temperature to obtain an iron-based alloy. The contents of Fe, Ni, Co, and Cu in the iron-based alloy were determined using X-ray fluorescence spectrometry (XRF) and inductively coupled plasma atomic emission spectrometry (ICP), as shown in Table 3.
[0080] Table 3. Main chemical components of iron-based alloys recovered from nickel slag.
[0081] element Fe Ni Co Cu Content / wt% 97.60 0.99 0.32 0.59
[0082] (2) The iron-based alloy is mixed evenly with Ni powder, Co powder and Cu powder. The resulting mixture (Fe:Ni:Co:Cu molar ratio = 1:1:1:0.4) is placed in a vacuum melting furnace and heated at 1800℃ for 5×10⁻⁶ hours. -3 Under Pa conditions, vacuum melting for 30 min yields a magnetic high-entropy alloy (Fe). 28.1 Ni 29.6 Co 29.6 Cu 12.8 The magnetic properties of the high-entropy magnetic alloy were characterized using a vibrating magnetometer (VSM), and the results are as follows: Figure 3 As shown, by Figure 3 It can be seen that the saturation magnetization of the magnetic high-entropy alloy is 107 emu / g, indicating excellent magnetic properties.
[0083] Example 4
[0084] (1) After crushing the copper slag, sieve it through a 200-mesh screen. Take 80g of the copper slag powder that is sieved through the screen and mix it evenly with 11.38g of CaO. Compress the mixture into tablets for 25s at room temperature and 20MPa. Place the resulting modified copper slag tablets in a corundum crucible and heat them to 1500℃ in a muffle furnace at a heating rate of 5℃ / min. Hold the temperature for 60min to melt and oxidize. Then cool the mixture to room temperature at a rate of 5℃ / min and crush it to below 200 mesh. Place the oxidized metallurgical slag (powder) aqueous suspension (concentration of 100g / L) into a magnetic separator at a flow rate of 1.5L / min and perform magnetic separation at 200mT to obtain magnetite powder. The magnetite powder, coal powder, bentonite, and sodium carbonate were mixed in a mass ratio of 1:0.4:0.02:0.02 and pelletized. The resulting magnetite pellets with a diameter of 12–18 mm were vacuum dried at 80 °C for 6 hours to constant weight. They were then placed in a graphite crucible and heated to 1300 °C in a vertical tube furnace under a nitrogen atmosphere at a heating rate of 5 °C / min. The mixture was then held at this temperature for 60 minutes for coal-based reduction and cooled to room temperature at a rate of 80 °C / min under air-isolated conditions to obtain metallized pellets. These metallized pellets were placed in an electric furnace and held at 1700 °C for 60 minutes, then cooled to room temperature to obtain an iron-based alloy. The contents of Fe, Ni, Co, and Cu in the iron-based alloy were determined using X-ray fluorescence spectrometry (XRF) and inductively coupled plasma atomic emission spectrometry (ICP), as shown in Table 4.
[0085] Table 4. Main chemical components of iron-based alloys recovered from copper slag.
[0086] element Fe Ni Co Cu Content / wt% 91.60 0.04 0.02 7.82
[0087] (2) The iron-based alloy is mixed evenly with Ni powder, Co powder and Cu powder. The resulting mixture (Fe:Ni:Co:Cu molar ratio = 1:1:1:0.8) is placed in a vacuum melting furnace and heated at 1800℃ and 5×10⁻⁶ ℃. -3 Under Pa conditions, vacuum melting for 30 min yields a magnetic high-entropy alloy (Fe). 24.9 Ni 26.2 Co 26.2 Cu 22.7 The magnetic properties of the high-entropy magnetic alloy were characterized using a vibrating magnetometer (VSM), and the results are as follows: Figure 4 As shown, by Figure 4 It can be seen that the saturation magnetization of the magnetic high-entropy alloy is 81 emu / g, indicating excellent magnetic properties.
[0088] Example 5
[0089] (1) After crushing the copper slag, sieve it through a 200-mesh screen. Take 80g of the copper slag powder that is sieved through the screen and mix it evenly with 11.38g of CaO. Compress the mixture into tablets for 25s at room temperature and 20MPa. Place the resulting modified copper slag tablets in a corundum crucible and heat them to 1450℃ in a muffle furnace at a heating rate of 5℃ / min. Hold the temperature for melting and oxidation for 60min. Then cool them to room temperature at a rate of 5℃ / min and crush them to below 200 mesh. Place the oxidized metallurgical slag (powder) aqueous suspension (concentration of 100g / L) into a magnetic separator at a flow rate of 1.5L / min and perform magnetic separation at 200mT to obtain magnetite powder. The magnetite powder, coal powder, bentonite, and sodium carbonate were mixed in a mass ratio of 1:0.4:0.02:0.02 and pelletized. The resulting magnetite pellets with a diameter of 12–18 mm were vacuum dried at 80 °C for 6 hours to constant weight. They were then placed in a graphite crucible and heated to 1300 °C in a vertical tube furnace under a nitrogen atmosphere at a heating rate of 5 °C / min. The mixture was then held at this temperature for 60 minutes for coal-based reduction and cooled to room temperature at a rate of 80 °C / min under air-isolated conditions to obtain metallized pellets. These metallized pellets were placed in an electric furnace and held at 1700 °C for 60 minutes, then cooled to room temperature to obtain an iron-based alloy. The contents of Fe, Ni, Co, and Cu in the iron-based alloy were determined using X-ray fluorescence spectrometry (XRF) and inductively coupled plasma atomic emission spectrometry (ICP), as shown in Table 5.
[0090] Table 5. Main chemical components of iron-based alloys recovered from copper slag.
[0091] element Fe Ni Co Cu Content / wt% 92.11 0.03 0.02 7.32
[0092] (2) The iron-based alloy is mixed evenly with Ni powder, Co powder and Cu powder. The resulting mixture (Fe:Ni:Co:Cu molar ratio = 1:1:1:0.6) is placed in a vacuum melting furnace and heated at 1800℃ and 5×10⁻⁶ °C. -3 Under Pa conditions, vacuum melting for 30 min yields a magnetic high-entropy alloy (Fe). 26.3 Ni 27.8 Co 27.8 Cu 18.1 The magnetic properties of the high-entropy magnetic alloy were characterized using a vibrating magnetometer (VSM), and the results are as follows: Figure 5 As shown, by Figure 5 It can be seen that the saturation magnetization of the magnetic high-entropy alloy is 95 emu / g, indicating excellent magnetic properties.
[0093] Example 6
[0094] (1) After crushing the copper slag, sieve it through a 200-mesh screen. Take 80g of the copper slag powder that is sieved through the screen and mix it evenly with 7.81g of CaO. Compress the mixture into tablets for 25s at room temperature and 20MPa. Place the resulting modified copper slag tablets in a corundum crucible and heat them to 1400℃ in a muffle furnace at a heating rate of 5℃ / min. Hold the temperature for melting and oxidation for 60min. Then cool them to room temperature at a rate of 5℃ / min and crush them to below 200 mesh. Place the oxidized metallurgical slag (powder) aqueous suspension (concentration of 100g / L) into a magnetic separator at a flow rate of 1.5L / min and perform magnetic separation at 200mT to obtain magnetite powder. The magnetite powder, coal powder, bentonite, and sodium carbonate were mixed in a mass ratio of 1:0.4:0.02:0.02 and pelletized. The resulting magnetite pellets with a diameter of 12–18 mm were vacuum dried at 80 °C for 6 h to constant weight. They were then placed in a graphite crucible and heated to 1300 °C in a vertical tube furnace under a nitrogen atmosphere at a heating rate of 5 °C / min. The mixture was then held at this temperature for 60 min for coal-based reduction and cooled to room temperature at a rate of 80 °C / min under air-isolated conditions to obtain metallized pellets. These metallized pellets were placed in an electric furnace and held at 1700 °C for 60 min, then cooled to room temperature to obtain an iron-based alloy. The contents of Fe, Ni, Co, and Cu in the iron-based alloy were determined using X-ray fluorescence spectrometry (XRF) and inductively coupled plasma atomic emission spectrometry (ICP), as shown in Table 6.
[0095] Table 6. Main chemical components of iron-based alloys recovered from copper slag.
[0096] element Fe Ni Co Cu Content / wt% 92.31 0.03 0.02 7.12
[0097] (2) The iron-based alloy is mixed evenly with Ni powder, Co powder and Cu powder. The resulting mixture (Fe:Ni:Co:Cu molar ratio = 1:1:1:0.4) is placed in a vacuum melting furnace and heated at 1800℃ for 5×10⁻⁶ hours. -3 Under Pa conditions, vacuum melting for 30 min yields a magnetic high-entropy alloy (Fe). 28.1 Ni 29.6 Co 29.6 Cu 12.8 The magnetic properties of the high-entropy magnetic alloy were characterized using a vibrating magnetometer (VSM), and the results are as follows: Figure 6 As shown, by Figure 6 It can be seen that the saturation magnetization of the magnetic high-entropy alloy is 103 emu / g, indicating excellent magnetic properties.
[0098] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a magnetic high-entropy alloy, characterized in that, Includes the following steps: Iron-rich metallurgical slag is mixed with CaO, molten and oxidized, and then cooled to obtain oxidized metallurgical slag. The oxidized metallurgical slag is then subjected to magnetic separation to obtain magnetite powder. The iron-rich metallurgical slag includes copper slag and / or nickel slag. The nickel slag comprises the following components by mass percentage: TFe 30-50%, SiO2 30-50%, MgO 1-15%, CaO 1-5%, Al2O3 2.5-6%, Ni 0.3-0.6%, Co 0.05-0.1%, Cu 0.2-0.4%. The copper slag comprises the following components by mass percentage: TFe 40-60%, Cu 0.5%-6%, SiO2 20-40%, MgO 1-8%, CaO 1-20%, Ni <0.1%, Co <0.1%. The magnetite powder, coal powder and pelletizing agent are mixed and then subjected to pelletizing, coal-based reduction and second cooling in sequence to obtain metallized pellets. The metallized pellets are subjected to melting and separation treatment to obtain an iron-based alloy; the iron-based alloy comprises the following components in mass percentage: Fe 90~99%, Ni 0.01~1%, Co 0.01~0.35%, Cu 0.5~8%; The iron-based alloy, Ni, Co and Cu are mixed, and the resulting mixture is vacuum melted to obtain a magnetic high-entropy alloy; the molar ratio of Fe, Ni, Co and Cu in the mixture is 1:1:1:0.4~1.
2. The preparation method according to claim 1, characterized in that, The mass ratio of the iron-rich metallurgical slag to CaO is 1:0.08~0.25; The melting oxidation temperature is 1350~1500℃, and the holding time is 30~60min; The cooling rate of the first cooling is 5~10℃ / min.
3. The preparation method according to claim 1, characterized in that, The conditions for magnetic separation include: a magnetic field strength of 100~300mT, the use of the oxidized metallurgical slag in the form of an oxidized metallurgical slag aqueous suspension, and a flow rate of the oxidized metallurgical slag aqueous suspension of 1~2L / min.
4. The preparation method according to claim 1, characterized in that, The pelleting agent comprises sodium carbonate and bentonite; the mass ratio of sodium carbonate to bentonite is 1:1~4. The mass ratio of magnetite powder, coal powder, and pelletizing agent is 1:0.25~0.4:0.03~0.06; The diameter of the magnetite pellets obtained by pelletizing is 12~18mm; The coal-based reduction temperature is 1150~1350℃, and the holding time is 30~60min; The second cooling rate is 30~100℃ / min, and the second cooling is carried out under air-isolated conditions.
5. The preparation method according to claim 1, characterized in that, The melting treatment temperature is 1550~1750℃, and the holding time is 40~120min.
6. The preparation method according to claim 1, characterized in that, The vacuum melting temperature is 1600~2000℃, the holding time is 10~60min, and the vacuum degree is 3×10⁻⁶. -3 ~5×10 -3 Pa.
7. The magnetic high-entropy alloy prepared by the preparation method according to any one of claims 1 to 6.