A method for extracting magnesium from lf refining slag

Abstract

The application discloses a method for extracting Mg from LF refining slag, comprising the following steps: (1) placing the LF refining slag after casting in a vacuum chamber, adding a reducing agent to obtain mixed reaction materials, wherein the reducing agent comprises FeSi powder and Al powder; (2) vacuumizing the system, heating and reacting the mixed reaction materials, and cooling the generated magnesium vapor into crude magnesium outside the vacuum chamber. The method realizes green and resource recycling of the LF refining slag, avoids defects in traditional hot reduction method for producing magnesium, rapidly produces high-value-added magnesium by utilizing the waste heat of the LF refining slag, and realizes large-scale utilization of the LF refining slag. The method has simple process and low cost, does not need to add fluorite as a mineralizing agent, and avoids fluorine pollution problems in the production of Mg.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of metallurgy, and particularly relates to a method for extracting Mg from LF refining slag. BACKGROUND

[0002] LF refining slag is waste slag produced in the LF refining process. After most of the LF refining slag is recycled for metal Fe, the powder slag is stored, which causes serious powder dusting, occupies and pollutes the land, is not conducive to environmental protection and causes resource waste. At present, domestic and foreign scholars have made many studies on the LF refining slag recycling and utilization process, such as being used as a slagging agent for converter or electric furnace steelmaking, a building raw material and the like. However, the existing research methods still have some defects: (1) due to the limitations of the workshop, hoisting equipment, product outline and production organization and the like, the hot slag recycling is relatively low, and changes in 20%-50%, and the LF refining slag after recycling still needs to be discarded and treated; (2) after the LF refining slag is cooled and crushed, the heat cannot be fully utilized, the cold slag material is used for slagging in the next cycle, and the slagging speed is slow, which is not conducive to energy saving and consumption reduction; (3) the LF refining slag hot state oxidation method slag desulfurization technology is difficult to realize due to the limitation of production space, and it is difficult to guarantee the high-temperature gas at 1300-1450℃; (4) the solid-state hydrothermal leaching method slag desulfurization wastes a large amount of cooling water and steel slag heat in the treatment process, and also causes secondary pollution.

[0003] Therefore, it is necessary to provide a high-value-added energy-saving and emission-reducing recycling method of LF refining hot slag, so as to achieve the purpose of circular production and zero emission. SUMMARY

[0004] The present application is based on the discovery and understanding of the inventors on the following facts and problems: at present, the LF refining slag has the problems of low recycling rate, low-value-added utilization, easy dusting during stacking, environmental pollution and the like. The steel enterprises cannot fully utilize the LF refining slag, and the utilization rate of the LF refining slag is less than 20%, and even after the recycling for one time, the LF refining slag is finally discarded, and the LF refining slag which cannot be recycled can only be poured into the slag tank to solidify and then transported to the slag field for treatment together with the converter slag or electric furnace slag. The steel slag contains P, and the ore blending is limited, and basically cannot be used for sintering, and can only be used for stacking after the metal Fe is recycled, which occupies and pollutes the land; a large amount of steel slag is discarded or used as raw materials to produce cement and the like low-value-added products; the LF refining slag stacking causes serious powder dusting, which is not conducive to environmental protection and causes resource waste.

[0005] The industrial magnesium production methods mainly include electrolysis method, carbon thermal reduction method, Pidgeon method and Magnetherm semi-continuous magnesium production process. Since the beginning of the 21st century, the industrial magnesium production method is mainly the Pidgeon method, and the Pidgeon method accounts for more than 80% of the global production. The traditional thermal reduction method for producing magnesium has some defects: (1) The production uses dolomite, magnesite and other mineral resources as raw materials, the resources are limited, and the mining process and the generated mineral waste destroy the natural ecological environment; (2) The reactants silicon iron and calcined dolomite are subjected to solid phase chemical reaction, the reaction rate is slow, the reduction reaction period is as long as 10-12 hours, and the efficiency is low; (3) The magnesium production process is carried out at high temperature, the raw materials are mixed at room temperature, then heated to the high temperature of 1200-1250 DEG C required for reaction, and the duration is long, a large amount of fuel is consumed, and the high-temperature calcined dolomite process is carried out separately, which further increases the fuel consumption and processing cost of the production process, the duration is long, and the energy consumption of the production process is large; (4) Flame external heating is adopted, heat is gradually conducted from the outside to the inside of the reactor, the production period is long, the heat loss is large, the heat energy utilization rate is low, and the heat energy utilization rate of the typical process is only about 20%; (5) CaF2 is added in the production, which pollutes the environment. In addition, there are other defects such as serious smoke pollution in production, periodic intermittent production, difficulty in realizing automatic operation and large-scale production and the like.

[0006] In summary, how to green and resource recycling of LF refining slag, and how to avoid the defects of low efficiency of traditional thermal reduction method for producing magnesium need to be further explored and researched.

[0007] The present application aims to at least solve one of the technical problems in the related art. To this end, the embodiments of the present application propose a method for extracting Mg from LF refining slag, which can green and resource recycling of LF refining slag, can avoid the defects of traditional thermal reduction method for producing magnesium, can rapidly produce high value-added magnesium by using the waste heat of LF refining slag, and can realize large-scale utilization of LF refining slag, the process is simple, the cost is low, no fluorite is added as a mineralizer, and the fluorine pollution problem in the production of Mg is avoided.

[0008] The embodiments of the present application propose a method for extracting Mg from LF refining slag, comprising the following steps:

[0009] (1) The LF refining slag after pouring is placed in a vacuum chamber, a reducing agent is added, and a mixed reaction material is obtained, wherein the reducing agent comprises FeSi powder and Al powder;

[0010] (2) The system is vacuumized, the mixed reaction material is heated and reacted, and the generated magnesium vapor is cooled to form crude magnesium outside the vacuum chamber.

[0011] The method for extracting Mg from LF refining slag according to the embodiment of the present application has the following advantages and technical effects: 1. The method according to the embodiment of the present application uses the LF refining slag after pouring as raw material, and the LF refining slag is an industrial solid waste. The LF refining slag is used to replace the traditional industrial magnesium smelting raw material such as dolomite or magnesite, thereby saving the non-renewable mineral resources, realizing the recycling of waste, reducing the cost, reducing the storage of LF refining slag and environmental pollution, and achieving environmental protection and energy saving; 2. The method according to the embodiment of the present application uses the LF refining slag after pouring to be reduced under the condition of vacuum and high temperature. Since the LF refining slag after pouring has high residual temperature, the LF refining slag itself contains a large amount of sensible heat, which can preheat the reducing agent FeSi and Al powder and provide part of the energy for the reaction of MgO in the LF refining slag. After adding part of the heat, the needs of the reduction reaction can be met, and the residual temperature of the LF refining slag after pouring is fully utilized; 3. In the method according to the embodiment of the present application, Al powder is added to the reducing agent. Since Al releases heat in the reduction reaction, the reaction can be promoted, and the production cycle can be shortened, thereby solving the problems of high energy consumption, low reaction rate and long production cycle in the pure silicon-thermal method for reducing and smelting magnesium; 4. The method according to the embodiment of the present application has a fast reaction rate and high efficiency. The raw material does not need to be mixed at room temperature and then heated to a high temperature required for the reaction in a cold state. The heat is conducted by the raw material itself, the heat loss is small, the heat energy utilization rate is high, the fuel is saved, and the production energy consumption can be greatly reduced; 5. In the method according to the embodiment of the present application, the raw material LF refining slag is subjected to a high-temperature slagging process, thereby reducing the activation energy of the reaction and speeding up the reaction. Therefore, fluorite mainly composed of CaF2 does not need to be added to play a role in catalyzing the reaction, and the pollution of fluorine to the environment is avoided, thereby fundamentally solving the problem of fluorine pollution in the production of Mg in the traditional process.

[0012] In some embodiments, in the step (1), the Si content in the FeSi powder is 72wt%-78wt%; and / or, the Al content in the Al powder is 95wt%-99wt%.

[0013] In some embodiments, in the step (1), the adding amount of the reducing agent is 4wt%-10wt% of the LF refining slag.

[0014] In some embodiments, in the step (1), the reducing agent includes 30-50% of FeSi powder and 50-70% of Al powder in terms of mass.

[0015] In some embodiments, in the step (1), the temperature of the LF refining slag after pouring is above 1200℃.

[0016] In some embodiments, in step (1), the LF refining slag after pouring is poured into a slag ladle, and then placed in a vacuum chamber, the slag ladle is used as a reaction container, the reducing agent is added in batches, and the mixture is uniformly mixed to obtain a mixed reaction material.

[0017] In some embodiments, in step (2), the vacuum degree of the vacuum chamber is 5-20 Pa.

[0018] In some embodiments, in step (2), the temperature is heated to 1200-1300℃.

[0019] In some embodiments, in step (2), the reaction time is 0.8-2 hours.

[0020] The embodiment of the present application also provides an application of the LF refining slag in extracting Mg, and the Mg is extracted by the method of the embodiment of the present application. In the embodiment of the present application, the application range of the LF refining slag is expanded, the green and resource recycling of the LF refining slag is realized, the defects in the traditional hot reduction method for producing Mg are avoided, the high value-added Mg is rapidly produced by using the waste heat of the LF refining slag, the recycled Mg is reused in steelmaking production, the large-scale utilization of the LF refining slag is realized, the process is simple, the cost is low, the fluorite as a mineralizer is not added, and the fluorine pollution problem in the production of Mg is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the implementation flowchart of the LF refining slag for extracting Mg in the embodiment of the present application. DETAILED DESCRIPTION

[0022] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0023] As shown in the figure, the method for extracting Mg by the LF refining slag in the embodiment of the present application comprises the following steps: Figure 1

[0024] (1) The LF refining slag after pouring is placed in a vacuum chamber, and a reducing agent is added to obtain a mixed reaction material, wherein the reducing agent comprises FeSi powder and Al powder;

[0025] (2) The system is vacuumized, the mixed reaction material is heated, and the generated magnesium vapor is cooled into crude magnesium outside the vacuum chamber.

[0026] ​The method for extracting Mg from LF refining slag according to the embodiment of the present application uses the LF refining slag after pouring as raw material, and the LF refining slag is an industrial solid waste. The LF refining slag is used to replace the traditional industrial magnesium smelting raw material such as dolomite or magnesite, which saves the non-renewable mineral resources, realizes the recycling of waste, has low cost, reduces the storage of LF refining slag and environmental pollution, and is environmentally friendly and energy-saving. In the method of the embodiment of the present application, the LF refining slag after pouring is reduced under the condition of vacuum and high temperature. Since the LF refining slag after pouring has high residual temperature, the raw material LF refining slag itself contains a large amount of sensible heat, which can preheat the reducing agent FeSi and Al powder and provide part of the energy for the reaction of MgO in the LF refining slag. After adding part of the heat, the needs of the reduction reaction can be met, and the residual temperature of the LF refining slag after pouring is fully utilized. In the method of the embodiment of the present application, Al powder is added to the reducing agent. Different from the endothermic of FeSi in the process of reducing Mg, Al releases heat in the reduction reaction, which can promote the reaction and is beneficial to shorten the production cycle, thereby solving the problems of high energy consumption, low reaction rate and long production cycle existing in the pure silicon thermal reduction method for smelting magnesium. The method of the embodiment of the present application has fast reaction rate and high efficiency. The raw material does not need to be mixed from room temperature and then heated to high temperature required for the reaction in cold state. The heat is conducted through the raw material itself, the heat loss is small, the heat energy utilization rate is high, the fuel is saved, and the production energy consumption can be greatly reduced. In the method of the embodiment of the present application, the raw material LF refining slag is subjected to a high-temperature slagging process, which reduces the activation energy of the reaction, and the reaction speed is fast. Therefore, fluorite mainly composed of CaF2 does not need to be added, which can play a role in catalyzing the reaction, and the pollution of fluorine to the environment is avoided, and the problem of fluorine pollution in the process of producing Mg by the traditional process is fundamentally avoided.

[0027] In some embodiments, in step (1), the Si content in the FeSi powder is 72wt%-78wt%, specifically, for example, 72wt%, 73wt%, 74wt%, 75wt%, 76wt%, 77wt%, 78wt%, preferably 75# FeSi; and / or the Al content in the Al powder is 95wt%-99wt%, specifically, for example, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%. In the embodiment of the present application, the Si content in the FeSi powder and the Al content in the Al powder are further preferred, which is beneficial to further improve the efficiency of extracting Mg, promote the reaction, reduce the energy consumption, and shorten the production cycle.

[0028] In some embodiments, in the step (1), the amount of the reducing agent added is 4wt%-10wt% of the LF refining slag, specifically, for example, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%. In the embodiments of the present application, the reducing agent is added in excess, which increases the cost; and the reducing agent is added in insufficient amount, which cannot extract the magnesium in the LF refining slag sufficiently, and the magnesium recovery rate is low. By further optimizing the amount of the reducing agent added, the extraction efficiency of Mg is further improved, the magnesium recovery rate is improved, the cost is reduced, the energy consumption is reduced, and the production cycle is shortened.

[0029] In some embodiments, in the step (1), the reducing agent comprises 30-50% of FeSi powder and 50-70% of Al powder, by mass, specifically, for example, 30%, 35%, 40%, 45%, 50% of FeSi powder; and 50%, 55%, 60%, 65%, 70% of Al powder. In the embodiments of the present application, the FeSi powder and the Al powder are used to form the reducing agent, and the Al powder is added to the reducing agent, which is different from the endothermic reaction of FeSi in the process of reducing Mg, and the Al powder can promote the reaction to proceed rapidly because it releases heat in the reduction reaction, which is beneficial to shorten the production cycle, and the addition of too much Al powder will greatly increase the production cost, and the addition of too little Al powder will not obviously promote the reaction. By further optimizing the content of the FeSi powder and the Al powder in the reducing agent, the extraction efficiency of Mg is further improved, the reaction is promoted, the energy consumption is reduced, and the production cycle is shortened.

[0030] In some embodiments, in the step (1), the LF refining slag after pouring, i.e., the LF refining slag returned after pouring, preferably, the temperature of the LF refining slag after pouring is above 1200°C. In the embodiments of the present application, the temperature of the LF refining slag after pouring is above 1200°C, which can fully utilize the large amount of sensible heat contained in the LF refining slag itself, preheat the reducing agent, and provide part of the energy for the reaction with MgO in the LF refining slag, so that only part of the heat needs to be supplemented to meet the needs of the reduction reaction, and the waste heat of the LF refining slag after pouring is fully utilized.

[0031] In some embodiments, in the step (1), the reducing agent is added in batches. In the embodiments of the present application, the reducing agent is added in batches, which is beneficial to the full and efficient progress of the reduction reaction.

[0032] In some embodiments, in the step (1), the LF refining slag after pouring is poured from a ladle into a slag pot, and then placed in a vacuum chamber, the slag pot is used as a reaction container, the reducing agent is added in batches, mixed, and a mixed reaction material is obtained. In the embodiments of the present application, the slag pot is directly used as a reaction container, and no additional production investment is needed, which is beneficial to production management and cost reduction.

[0033] In some embodiments, in the step (2), the vacuum chamber is vacuumized, and then the mixed reactant is heated; preferably, the vacuum degree of the vacuum chamber is 5-20 Pa, specifically, for example, 5 Pa, 6 Pa, 8 Pa, 10 Pa, 12 Pa, 15 Pa, 18 Pa, 20 Pa. In the embodiments of the present application, the vacuum degree is preferred, which is beneficial to improve the extraction efficiency of Mg and improve the recovery rate of Mg.

[0034] In some embodiments, in the step (2), the heating temperature is 1200-1300℃, specifically, for example, 1200℃, 1220℃, 1250℃, 1270℃, 1290℃, 1300℃; and the reaction time is 0.8-2 hours, specifically, for example, 0.8 hours, 1 hour, 1.2 hours, 1.5 hours, 1.8 hours, 2 hours. In the embodiments of the present application, the raw material LF refining slag itself contains a large amount of sensible heat, and after heating to supplement part of the heat, the needs of the reduction reaction can be met, the reaction rate is fast, the production cycle is short, the efficiency is high, and the recovery rate of Mg is high. By optimizing the heating temperature and the reaction time, it is beneficial to further improve the extraction efficiency of Mg and improve the recovery rate of Mg.

[0035] In some embodiments, in the step (2), under the suction of the vacuum system, the magnesium vapor condenses into crude magnesium at the cooling end outside the vacuum chamber.

[0036] The embodiments of the present application also propose an application of LF refining slag in extracting Mg, and Mg is extracted by the method of the embodiments of the present application. In the embodiments of the present application, the application range of the LF refining slag is expanded, green and resource recycling of the LF refining slag is realized, the defects of the traditional hot reduction method for producing Mg are avoided, the residual heat of the LF refining slag is utilized to rapidly produce high value-added Mg, the recovered Mg is re-applied to steelmaking production, large-scale utilization of the LF refining slag is realized, the process is simple, the cost is low, no fluorite is added as a mineralizer, and the fluorine pollution problem in the production of Mg is avoided.

[0037] The present application will be described below with reference to specific embodiments, and it should be noted that these embodiments are merely descriptive and do not limit the present application in any way.

[0038] Taking 260t LF production as an example, the amount of LF refining slag is usually calculated as 3t / furnace. The temperature of the LF refining slag returned in the ladle after casting is above 1200℃.

[0039] Embodiment 1

[0040] (1) Reducing agent preparation: FeSi powder with Si content of 75wt% and Al powder with Al content of 95wt% are added, the reducing agent is added at 10wt% of the LF refining slag, the ratio of the reducing agent is 50wt% FeSi powder and 50wt% Al powder, the amount of addition is 300kg, among which the FeSi powder with Si content of 75wt% is 150kg, the Al powder with Al content of 95wt% is 150kg, and the mixture is uniformly mixed for use;

[0041] (2) The LF refining slag after pouring is poured into a slag tank and transported to a vacuum chamber. The slag tank is used as a reaction container, the temperature of the LF refining slag returned after pouring is above 1200°C, the reducing agent is added in batches, then the mixture is uniformly mixed to obtain a mixed reaction material;

[0042] (3) The system is vacuumized, the vacuum degree is 20Pa, the mixed reaction material in the slag tank is heated to 1300°C in the vacuum chamber, and the temperature is kept constant for 0.8 hours. Under the suction of the vacuum system, the magnesium vapor generated by the reaction is condensed into crude magnesium at the cooling end outside the vacuum chamber for recovery.

[0043] The main components of the LF refining slag before and after the reaction are shown in Table 1.

[0044] Table 1: Main components of the refining slag before and after the reaction

[0045] Slag sample CaO (wt%) SiO2 (wt%) MgO (wt%) Al2O3 (wt%) Before reduction to Mg 50 11 8 25 After reduction Example 1 47 18 0.8 32

[0046] Through the method of the embodiment, the Mg recovery rate is 89%.

[0047] Example 2

[0048] (1) Reducing agent preparation: FeSi powder with Si content of 72wt% and Al powder with Al content of 99wt% are added, the reducing agent is added at 4wt% of the LF refining slag, the ratio of the reducing agent is 30wt% FeSi powder and 70wt% Al powder, the amount of addition is 120kg, among which the FeSi powder with Si content of 72wt% is 36kg, the Al powder with Al content of 99wt% is 84kg, and the mixture is uniformly mixed for use;

[0049] (2) The LF refining slag after pouring is poured into a slag tank and transported to a vacuum chamber. The slag tank is used as a reaction container, the temperature of the LF refining slag returned after pouring is above 1200°C, the reducing agent is added in batches, then the mixture is uniformly mixed to obtain a mixed reaction material;

[0050] (3) The system is vacuumized, the vacuum degree is 12Pa, the mixed reaction material in the slag tank is heated to 1250°C in the vacuum chamber, and the temperature is kept constant for 1.5 hours. Under the suction of the vacuum system, the magnesium vapor generated by the reaction is condensed into crude magnesium at the cooling end outside the vacuum chamber for recovery.

[0051] The main components of the LF refining slag before and after the reaction are shown in Table 2.

[0052] Table 2: Main components of the refining slag before and after the reaction

[0053] Slag sample CaO (wt%) SiO2(wt%) MgO (wt%) Al2O3 (wt%) Before reduction to Mg 47 12 8 29 After reduction Example 2 46 14 1.6 34

[0054] The Mg recovery rate is 80% through the method of the embodiment.

[0055] Embodiment 3

[0056] (1) Reducing agent preparation: FeSi powder with a Si content of 75wt% and Al powder with an Al content of 97wt% are added, the reducing agent is added at 7wt% of the LF refining slag, the proportion of the reducing agent is 40wt% FeSi powder and 60wt% Al powder, the amount of the reducing agent added is 210kg, wherein the amount of FeSi powder with a Si content of 75wt% is 84kg, and the amount of Al powder with an Al content of 97wt% is 126kg, which are mixed and used;

[0057] (2) The LF refining slag after pouring is poured into a slag tank and transported to a vacuum chamber. The slag tank is used as a reaction container, the temperature of the LF refining slag returned after pouring is above 1200℃, the reducing agent is added in batches, and then the mixture is uniformly mixed to obtain a mixed reaction material;

[0058] (3) The system is vacuumized, the vacuum degree is 5Pa, the mixed reaction material in the slag tank is heated to 1200℃ in the vacuum chamber, and the temperature is kept constant for 2 hours. Under the suction force of the vacuum system, the magnesium vapor generated by the reaction is condensed into crude magnesium at the cooling end outside the vacuum chamber.

[0059] The main components of the LF refining slag before and after the reaction are shown in Table 3.

[0060] Table 3: Main components of the refining slag before and after the reaction

[0061] Slag sample CaO (wt%) SiO2(wt%) MgO (wt%) Al2O3 (wt%) Before reduction to Mg 48 11 8 30 After reduction Example 3 46 15 1.4 37

[0062] The Mg recovery rate is 82% through the method of the embodiment.

[0063] Embodiment 4

[0064] The method is the same as that of embodiment 2, except that in the step (1), the proportion of the reducing agent is 70wt% FeSi powder and 30wt% Al powder, that is, the amount of the reducing agent added is 120kg, wherein the amount of FeSi powder with a Si content of 72wt% is 84kg, and the amount of Al powder with an Al content of 99wt% is 36kg, which are mixed and used.

[0065] The main components of the LF refining slag before and after the reaction are shown in Table 4.

[0066] Table 4: Main components of the refining slag before and after the reaction

[0067] Slag sample CaO (wt%) SiO2 (wt%) MgO (wt%) Al2O3 (wt%) Before reduction to Mg 47 12 8 29 After reduction Example 4 47 16 2.7 31

[0068] The Mg recovery rate was 65% by the method of this example.

[0069] Comparative Example 1

[0070] The method was the same as that of Example 1, except that the Al powder was not added to the reducing agent, and the reducing agent was added at 10 wt% of the LF refining slag, and the amount of FeSi powder with a Si content of 75 wt% added was 300 kg.

[0071] The main components of the LF refining slag before and after the reaction are shown in Table 5.

[0072] Table 5: Main components of the refining slag before and after the reaction

[0073] Slag sample CaO (wt%) SiO2(wt%) MgO (wt%) Al2O3 (wt%) Before reduction to Mg 50 11 8 25 After reduction Comparative Example 1 46 13 4.1 23

[0074] The Mg recovery rate was 44% by the method of Comparative Example 1.

[0075] Comparative Example 2

[0076] The method was the same as that of Example 1, except that the Al powder was not added to the reducing agent, and the reducing agent was added at 5 wt% of the LF refining slag, and the amount of FeSi powder with a Si content of 75 wt% added was 150 kg.

[0077] The main components of the LF refining slag before and after the reaction are shown in Table 6.

[0078] Table 6: Main components of the refining slag before and after the reaction

[0079] Slag sample CaO (wt%) SiO2(wt%) MgO (wt%) Al2O3 (wt%) Before reduction to Mg 50 11 8 25 After reduction Comparative Example 2 48 13 4.6 24

[0080] The Mg recovery rate was 40% by the method of Comparative Example 2.

[0081] In this disclosure, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific feature, structure, material, or characteristic being described is included in at least one embodiment or example of the present disclosure. The illustrative appearances of the above-mentioned terms in this specification are not necessarily the same. Moreover, the specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Additionally, the various embodiments or examples described in this specification are not necessarily mutually exclusive, and some embodiments or examples can be combined with each other or with other embodiments or examples.

[0082] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary, and are not to be construed as limiting the present application, and any changes, modifications, replacements, and variations of the above embodiments made by those skilled in the art are within the scope of the present application.

Claims

1. A method for extracting Mg from LF refining slag, characterized in that, Includes the following steps: (1) The cast LF refining slag is placed in a vacuum chamber and a reducing agent is added to obtain a mixed reaction material, wherein the reducing agent includes FeSi powder and Al powder; the temperature of the cast LF refining slag is above 1200℃; (2) The system is evacuated, the mixed reactants are heated and reacted, and the generated magnesium vapor is cooled into crude magnesium outside the vacuum chamber.

2. The method for extracting Mg from LF refining slag according to claim 1, characterized in that, In step (1), the Si content in the FeSi powder is 72wt%-78wt%; and / or, the Al content in the Al powder is 95wt%-99wt%.

3. The method for extracting Mg from LF refining slag according to claim 1, characterized in that, In step (1), the amount of reducing agent added is 4wt%-10wt% of the LF refining slag.

4. The method for extracting Mg from LF refining slag according to claim 1, characterized in that, In step (1), the reducing agent comprises 30-50% FeSi powder and 50-70% Al powder, by mass.

5. The method for extracting Mg from LF refining slag according to claim 1, characterized in that, In step (1), the cast LF refining slag is poured from the ladle into a slag pot, and then placed in a vacuum chamber. The slag pot is used as a reaction vessel, and the reducing agent is added in batches and mixed to obtain a mixed reaction material.

6. The method for extracting Mg from LF refining slag according to claim 1, characterized in that, In step (2), the vacuum degree of the vacuum chamber is 5-20 Pa.

7. The method for extracting Mg from LF refining slag according to claim 1, characterized in that, In step (2), the temperature is raised to 1200-1300℃.

8. The method for extracting Mg from LF refining slag according to claim 1, characterized in that, In step (2), the reaction time is 0.8-2 hours.

9. An application of LF refining slag in Mg extraction, characterized in that, Magnesium is extracted using the method described in any one of claims 1-8.

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