Method for smelting metallic manganese and metallic manganese

Abstract

The application provides a smelting method of metallic manganese and the metallic manganese, the method comprises the following steps: mixing a first manganese ore and a first lime, and then adding the mixture into a smelting furnace; adding a silicon-manganese alloy molten iron into the furnace; spraying oxygen at the top and inert gas at the bottom; adding a second manganese ore and a second lime during the spraying process; after the addition of the second manganese ore is completed, continuously spraying oxygen and inert gas until the temperature of the molten pool reaches a preset temperature, and then continuously spraying for 10-15 minutes; stopping the spraying of oxygen and continuously spraying the inert gas until the silicon content in the molten pool reaches a standard; transferring the melt into a ladle, standing, and then removing slag; casting; and obtaining the metallic manganese after cooling. The smelting method uses the silicon-manganese alloy molten iron as an initial heat source, and no additional heat is supplied during the process, which can effectively reduce the use of energy, has the characteristics of saving energy and reducing production cost, and effectively overcomes the high energy consumption caused by the continuous power supply in the existing smelting method of the metallic manganese by using an electric furnace.

Description

Technical Field

[0001] This application relates to the field of manganese metal smelting technology, and in particular to a method for smelting manganese metal and manganese metal. Background Technology

[0002] Manganese, often called the "vitamin of industry," plays an indispensable foundational role in modern industrial systems. Its applications are highly concentrated, with approximately 95% of manganese ore serving the metallurgical industry, particularly in steelmaking. It functions as a highly efficient desulfurizer and deoxidizer, purifying molten steel and improving its quality. It is also a key alloying element, significantly enhancing the strength and wear resistance of steel; for example, high-manganese steel with a manganese content of over 13% is a core material for manufacturing heavy machinery and railway turnouts. With the development of the new energy industry, manganese's application in batteries is increasingly prominent, becoming a core raw material for the cathode materials of power batteries such as lithium manganese oxide and ternary materials. It also has wide applications in the chemical and electronics industries. In the production of metallic manganese, there are mainly two methods: pyrometallurgical and hydrometallurgical. Although the hydrometallurgical method can obtain metallic manganese with higher purity, it is too polluting. Therefore, the pyrometallurgical method is still the mainstream production method. The main existing pyrometallurgical method for producing metallic manganese is the silicothermic process, which uses silicomanganese alloy as raw material and smelts it together with lime and manganese ore in an electric furnace to obtain metallic manganese. However, this smelting method requires a continuous supply of electricity to provide heat during the smelting process, which undoubtedly requires a large amount of energy and results in high energy consumption. Summary of the Invention

[0003] This application provides a method for smelting metallic manganese and metallic manganese, which solves the problem of high energy consumption caused by the need for continuous power supply when smelting metallic manganese in an electric arc furnace.

[0004] In a first aspect, this application provides a method for smelting metallic manganese, comprising the following steps: The first manganese ore and the first lime were mixed and added to the smelting furnace, and molten silicon-manganese alloy iron was added to the furnace. Turn on the spray gun at the top of the smelting furnace to spray oxygen into the furnace. At the same time, turn on the spray gun on the lower side of the smelting furnace to spray inert gas into the furnace. During the spraying process, add the second manganese ore and the second lime according to the second manganese ore feeding system. After the second manganese ore is fed, continue to inject oxygen and inert gas until the molten pool temperature reaches the preset temperature, then continue to inject for another 10-15 minutes, stop injecting oxygen, and continue to inject inert gas until the silicon content in the molten pool reaches the standard. The molten material is transferred to a ladle, allowed to stand, slag is removed, and the mixture is then cast and cooled to obtain metallic manganese.

[0005] Optionally, the feeding system for the second manganese ore is as follows: The second batch of manganese ore was divided into multiple batches of 100kg / batch, with the last batch containing less than 100kg being recorded as the final batch. Oxygen and inert gas are injected until the temperature of the molten pool reaches the initial temperature at which the silicon-manganese alloy molten iron is added, denoted as T; For every 100 kg of the second manganese ore added, the molten pool temperature is blown up to T ± 10℃ before adding the next batch of the second manganese ore, until the last batch of the second manganese ore is added. The amount of the second lime added is 60-80 kg of the second lime for every 100 kg of the second manganese ore added, until the second lime is completely added.

[0006] Optionally, the weight ratio of the first manganese ore to the second manganese ore is 1:(2~4), and the weight ratio of the first limestone to the second limestone is 1:(1~2). The ratio of the total weight of the first and second manganese ores to the weight of the molten ferrosilicon (1.1~1.3):1; The total weight ratio of the first and second limes to the molten silicon-manganese alloy is (0.6~0.8):1.

[0007] Optionally, the temperature of the molten silicon-manganese alloy is 1500~1550℃.

[0008] Optionally, the inert gas injection pressure is 1.2~2.4MPa, and the injection rate is 70~90Nm3 / t iron; The oxygen injection pressure is 1.2~2.4MPa, and the injection rate is 70~90Nm3 / t iron.

[0009] Optionally, the melt is transferred into a ladle and allowed to stand for 5-8 minutes.

[0010] Optionally, the inert gas is argon; The preset temperature is 1600~1650℃.

[0011] Optionally, the first and second manganese ores have the same manganese grade, both greater than 45%.

[0012] Optionally, the manganese content in the ferrosilicon alloy molten iron is greater than 65%, and the silicon content is greater than 28%.

[0013] Secondly, this application provides a metallic manganese, including manganese obtained by the smelting method described in the first aspect above.

[0014] 1) In the smelting method of this application, molten iron of silicon-manganese alloy is used as the initial heat source. The manganese ore is smelted through the exothermic reaction during smelting. No additional heat is supplied during the process. This method can effectively reduce the use of energy and has the characteristics of saving energy and reducing production costs. It effectively overcomes the drawback of high energy consumption caused by the need for continuous power supply in the existing method of smelting metallic manganese in electric furnace.

[0015] 2) This application does not introduce carbonaceous reducing agents during the smelting process, relying entirely on silicon in the ferrosilicon alloy as the reducing agent, fundamentally avoiding carbon contamination of the metallic manganese product. During the reaction, lime is added in stages (first lime and second lime) to control the slag basicity within a reasonable range, promoting the combination of SiO2 and CaO, effectively reducing the activity of MnO in the slag, making the reduction reaction more thorough, and significantly increasing the manganese content in the final product. Simultaneously, the stirring effect generated by inert gas injection promotes the flotation and removal of non-metallic inclusions, and the static slag removal operation further purifies the molten metal, reducing the inclusion content. After the smelting endpoint, the inert gas injection continues, utilizing the gas washing effect of the inert gas to remove residual gases and fine inclusions from the melt, improving the purity of the metallic manganese. The combined effect of the above measures results in metallic manganese products produced by the method of this application having high purity, low impurity content, and few inclusions, meeting the quality requirements of high-end alloy manufacturing for metallic manganese.

[0016] 3) This application employs an "initial charging + batch feeding" material addition method, combined with a composite blowing process of "oxygen injection heating + inert gas injection stirring," to construct a highly efficient reduction reaction system. In the initial stage, the first manganese ore and the first lime are pre-added to the furnace. After the ferrosilicon alloy molten iron is added, the silicon in the molten iron and the manganese ore rapidly undergo a displacement reaction. Simultaneously, initial slag quickly forms, covering the surface of the molten pool and effectively inhibiting the oxidation loss of manganese. During the smelting process, the second manganese ore and the second lime are added in batches according to a temperature-triggered charging system. Lime is added simultaneously with each batch of manganese ore to ensure that the SiO2 generated by the reaction is neutralized in a timely manner, maintaining the slag basicity within a reasonable range and avoiding the inhibition of the reduction reaction by the formation of manganese silicate. The heat provided by oxygen injection compensates for the endothermic demand of manganese ore reduction, and inert gas injection strengthens the stirring of the molten pool, breaking the diffusion boundary layer at the slag-metal interface and accelerating the mass transfer of silicon to the reaction interface. The synergistic effect of the above measures enables the silicon-reduced manganese ore reaction to maintain a high reaction rate throughout the entire smelting cycle, significantly improving the manganese reduction rate. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0018] In a first aspect, this application provides a method for smelting metallic manganese, comprising the following steps: The first manganese ore and the first lime were mixed and added to the smelting furnace, and then molten silicon-manganese alloy iron was added to the furnace.

[0019] The first manganese ore is used as the initial reactant, and the first lime is used as the initial slagging agent. The two are pre-mixed and added to the furnace, followed by the addition of high-temperature ferrosilicon alloy molten iron. This operational sequence ensures that the ferrosilicon alloy molten iron, manganese ore, and lime are in direct contact at the bottom of the furnace, avoiding the problem of manganese ore floating on the surface of the molten iron and insufficient contact with silicon caused by adding iron first and then charging other materials.

[0020] Turn on the spray gun at the top of the smelting furnace to inject oxygen into the furnace. At the same time, turn on the spray gun on the lower side of the smelting furnace to inject inert gas into the furnace. During the injection process, add the second manganese ore and the second lime according to the second manganese ore feeding system.

[0021] The role of oxygen injection is to oxidize silicon in the molten iron of silicon-manganese alloy, with the reaction formula Si + O2 = SiO2. This reaction is a strongly exothermic reaction, which can rapidly raise the temperature of the molten pool to the temperature window required for the manganese reduction reaction (1550~1650℃). Secondly, the role of argon injection is to generate strong stirring of the molten pool, break the diffusion boundary layer of the slag-metal interface, accelerate the mass transfer of silicon from the inside of the molten pool to the reaction interface, and at the same time, rapidly discharge the SiO2 generated by the reaction into the slag phase, avoiding the inhibition of the reaction by SiO2 enrichment at the interface.

[0022] After the second manganese ore is fed, continue to inject oxygen and inert gas until the molten pool temperature reaches the preset temperature. Then continue to inject oxygen for 10-15 minutes, stop injecting oxygen, and continue to inject inert gas until the silicon content in the molten pool reaches the standard.

[0023] In this application, the purpose of continuing to inject oxygen is to use the exothermic effect of silicon oxidation to raise the temperature of the molten pool to a preset value, ensuring that the slag has good fluidity; the purpose of continuing to inject inert gas is to use inert gas stirring to promote the further reaction between residual silicon and MnO in the slag after oxygen injection is stopped, to achieve deep reduction, until the residual silicon content in the molten pool drops to the target value (e.g., <0.5%).

[0024] The molten material is transferred to a ladle, allowed to stand, slag is removed, and the mixture is then cast and cooled to obtain metallic manganese.

[0025] The settling process allows the slag and metal to naturally separate due to their density difference. The slag removal operation removes the silicon-rich slag formed after the reaction, preventing it from mixing into the metal product during casting. Slow cooling after casting is conducive to the growth of manganese grains and the segregation of impurities at the grain boundaries, thereby improving product purity.

[0026] In this application, the crushing particle size of the first manganese ore and the second manganese ore is 10~30mm. To produce the same specification of metallic manganese, the method of this application can save 1200~1500kWh / t of metallic manganese compared with the traditional silicothermic method.

[0027] Optionally, the feeding system for the second manganese ore is as follows: The second batch of manganese ore was divided into multiple batches of 100kg / batch, with the last batch containing less than 100kg being recorded as the final batch. Oxygen and inert gas are injected until the temperature of the molten pool reaches the initial temperature at which the silicon-manganese alloy molten iron is added, denoted as T; For every 100 kg of the second manganese ore added, the molten pool temperature is blown up to T ± 10℃ before adding the next batch of the second manganese ore, until the last batch of the second manganese ore is added. The amount of the second lime added is 60-80 kg of the second lime for every 100 kg of the second manganese ore added, until the second lime is completely added.

[0028] The feeding system described in this application is a temperature-based batch feeding method: After the molten ferrosilicon alloy is added to the first manganese ore and the first lime, its temperature drops. To achieve better smelting results, it is necessary to first perform blowing (i.e., blowing oxygen and inert gas) to bring the melt temperature back to the initial temperature of the ferrosilicon alloy molten ore. Using this initial temperature T as a reference, when the melt temperature rises to the initial melt temperature T due to the exothermic oxidation of silicon, the first batch of 100 kg of the second manganese ore is added. After feeding, the melt temperature drops briefly due to the endothermic reaction. When the temperature rises again to T due to the exothermic oxidation of silicon, the next batch of 100 kg of the second manganese ore is added, and this process is repeated until all the manganese ore is added (since the amount of temperature drop after adding manganese ore is related to the size of the melt, taking 1 ton of melt as an example, the melt temperature drops by 8-12°C for every 100 kg of manganese ore added). 60-80 kg of the second lime is added simultaneously with each batch of manganese ore. The technical principle of this feeding system is that by using a "small batch, high frequency" feeding method, the manganese ore added each time can fully react at the slag-metal interface, avoiding incomplete local reaction or a sudden drop in the temperature of the molten pool caused by adding too much manganese ore at once; at the same time, the simultaneous addition of lime and manganese ore can neutralize the SiO2 generated by the reaction in time, maintain the slag alkalinity within a reasonable range (such as 1.0~2.5), and ensure that MnO is in a free state and continues to participate in the reduction reaction.

[0029] This feeding system enables the simultaneous addition of lime and manganese ore (60-80 kg of lime is added for every 100 kg of manganese ore; in practice, the addition can be scaled up or down according to this ratio), which keeps the slag composition relatively stable during the reaction process, avoids large fluctuations in slag properties, and improves the stability and controllability of the operation.

[0030] Optionally, the weight ratio of the first manganese ore to the second manganese ore is 1:(2~4), and the weight ratio of the first limestone to the second limestone is 1:(1~2). The ratio of the total weight of the first and second manganese ores to the weight of the molten ferrosilicon (1.1~1.3):1; The total weight ratio of the first and second limes to the molten silicon-manganese alloy is (0.6~0.8):1.

[0031] This application adds manganese ore in two parts. The first part (first manganese ore) is added to the furnace before molten iron is added, and the second part (second manganese ore) is added in batches during the smelting process. The amount of first manganese ore added is relatively small (accounting for 20%~33% of the total manganese ore). Its function is to allow the first manganese ore to come into direct contact with the molten iron when it is added to the ferrosilicon manganese alloy, where it melts rapidly at high temperatures and undergoes an initial reduction reaction, establishing a chemical environment for the slag-metal interface for subsequent reactions. If the proportion of first manganese ore is too high (>33%), the initial reaction will be too violent, potentially causing splashing or premature slag thickening. If the proportion of first manganese ore is too low (<20%), the amount of slag generated in the initial reaction will be insufficient to effectively cover the molten metal pool, resulting in direct contact between the manganese ore and the metal during subsequent charging, thus reducing reaction efficiency. The second manganese ore accounts for the majority (67%~80%), and its batch addition allows for precise control of the reaction rate.

[0032] The lime is added in two parts. The first part is pre-mixed with the first part of manganese ore and added to the furnace. Its function is to quickly melt and form initial slag after the molten iron of the silicon-manganese alloy is added, covering the surface of the molten metal pool, preventing the oxidation of manganese and absorbing the SiO2 generated in the early stage of the reaction. The second part of lime is added in a greater amount than or equal to the first part of lime (ratio 1:1~2), and is added in batches simultaneously with the second part of manganese ore. It is used to neutralize the SiO2 generated by the reduction of each batch of manganese ore in a timely manner and maintain the stability of slag basicity. If the proportion of the second part of lime is too high, the slag basicity will be too high in the later stage, which may cause the slag to thicken; if the proportion of the second part of lime is too low, the slag basicity will be insufficient in the later stage, and MnO will be bound by SiO2, hindering the reduction reaction. Generally, because the amount of the second lime is less than the amount of the second manganese ore, the lime will be added before the second manganese ore. In this case, after the second lime is added, continue the above operation (i.e., blow refining until the melt temperature rises to T±10℃) to add the second manganese ore. If the second manganese ore is added before the second lime, the second lime will also continue to be added, i.e., blow refining until the melt temperature rises to T±10℃) to add the second lime.

[0033] Optionally, the temperature of the molten silicon-manganese alloy is 1500~1550℃.

[0034] This application specifies the temperature of molten silicon-manganese alloy as 1500~1550℃.

[0035] The technical principle behind this temperature limit is that the liquidus temperature of silicon-manganese alloy varies with its composition, typically ranging from 1200 to 1300°C. However, if the molten iron is only heated above the liquidus, its initial temperature after being added to the smelting furnace will be insufficient to initiate the subsequent reduction reaction of the manganese ore. Controlling the molten iron temperature at 1500–1550°C serves several purposes: First, sufficient heat must be provided for the melting of manganese ore. Manganese ore (mainly composed of MnO2 or Mn3O4) has a melting point above 1600℃, but when it comes into contact with molten iron, it melts rapidly under high-temperature conditions and reacts with silicon in the iron. If the temperature of the molten iron is below 1500℃, the melting rate of the manganese ore decreases, the reaction interface area shrinks, and the reduction reaction rate decreases accordingly.

[0036] Secondly, it compensates for the temperature drop caused by the initial charging. Before adding the ferrosilicon alloy molten iron, the first batch of manganese ore and first batch of lime have been added to the furnace. These materials, which are at room temperature, will absorb heat, causing the temperature of the molten iron to drop. Setting the initial temperature of molten iron to 1500~1550℃ ensures that the temperature of the molten pool remains above 1400℃ after the iron is added, creating conditions for subsequent oxygen injection and reaction start-up.

[0037] Secondly, the initial reaction kinetics conditions were optimized. Within the temperature range of 1500–1550℃, the molten silicon-manganese alloy exhibited lower viscosity and better fluidity, resulting in more thorough contact with the manganese ore. Simultaneously, the rate constant for the reaction between silicon and MnO was higher within this temperature range, allowing the reaction to reach equilibrium in a shorter time.

[0038] In addition, if the molten iron temperature is below 1500℃, the temperature of the molten pool after adding iron may be below 1400℃, requiring a longer period of oxygen blowing to raise the temperature, which increases the smelting cycle and oxygen consumption; if the molten iron temperature is above 1550℃, although it is conducive to the start-up of the reaction, it will increase the energy consumption cost of the molten iron pretreatment stage, and the temperature control will be more difficult in the subsequent reaction process.

[0039] Optionally, the inert gas injection pressure is 1.2~2.4MPa, and the injection rate is 70~90Nm. 3 / t iron; The oxygen injection pressure is 1.2~2.4MPa, and the injection rate is 70~90Nm. 3 / t iron.

[0040] In this application, the injected gas must overcome the static pressure head of the molten pool (approximately 0.2~0.4 MPa) and pipeline resistance to enter the molten pool and create an effective stirring effect. When the injection pressure is below 1.2 MPa, the gas penetration depth is insufficient, and stirring only occurs on the surface of the molten pool, failing to achieve uniform mixing throughout the entire molten pool. When the injection pressure is above 2.4 MPa, the gas jet velocity is too high, which may cause violent splashing of the molten pool, while also increasing energy consumption and equipment wear. The pressure range of 1.2~2.4 MPa ensures that the gas jet penetrates the molten pool to a sufficient depth, forming a "mushroom-shaped" stirring zone, achieving thorough mixing of the metal and slag within the molten pool.

[0041] The injection rate is set based on reaction requirements and mass transfer enhancement requirements. For oxygen injection, the injection rate is 70~90 Nm³. 3 The amount of oxygen required for the silicon oxidation reaction is matched to that required for the molten iron (per ton of ferrosilicon manganese alloy). Each ton of molten iron contains approximately 280 kg of silicon, and complete oxidation requires approximately 224 Nm³ of oxygen. 3 (Theoretical value), but in this application, the role of oxygen injection is not only to oxidize silicon, but also to provide stirring energy. Therefore, the actual injection rate is lower than the theoretical value. Moreover, the oxidation of silicon does not completely depend on oxygen injection; most of the silicon is oxidized through the reduction reaction of MnO in the slag. For inert gas (argon) injection, the injection rate is (70~90 Nm³). 3 Argon ( / t iron) is mainly used to enhance mass transfer. Argon does not participate in the chemical reaction; its role is to generate bubbles. As these bubbles rise, they drive the flow of the molten pool, breaking the diffusion boundary layer at the slag-metal interface. Argon injection effectively eliminates localized compositional inhomogeneities. With oxygen and argon injection rates set to the same range, both can utilize the same gas supply system and spray gun structure, simplifying equipment configuration and reducing engineering implementation difficulty.

[0042] Optionally, the melt is transferred into a ladle and allowed to stand for 5-8 minutes.

[0043] After smelting, the melt consists of two phases: molten metal (mainly composed of manganese, silicon, iron, etc.) and slag (mainly composed of CaO-SiO2-MnO system). The settling process utilizes the density difference to achieve slag-metal separation (the density of metallic manganese is approximately 7.2 g / cm³). 3 The density of the slag is approximately 2.8~3.5 g / cm³. 3There are significant differences between the two. During the settling process, molten metal droplets settle and converge under gravity, while slag floats to the surface, thus purifying the molten metal and improving the purity of the final product. If the settling time is too short (<5 min), the slag-metal separation is incomplete, and some small molten metal droplets may be trapped in the slag and lost during slag removal, reducing the metal yield. If the settling time is too long (>8 min), the melt temperature continues to drop, the viscosity of the molten metal increases, and the fluidity during subsequent casting deteriorates, which may lead to incomplete casting or cold shut defects. In addition, prolonged settling also increases the erosion of the ladle refractory material and heat loss, affecting the energy consumption indicators of subsequent processes.

[0044] Optionally, the inert gas is argon; The preset temperature is 1600~1650℃.

[0045] In this application, argon is a commonly used inert gas in the metallurgical industry. It is chemically stable and does not react with molten metal or slag at high temperatures, thus avoiding the introduction of impurities. Compared to nitrogen, argon does not form nitrides (such as Mn3N2) with metallic manganese, preventing nitrogen contamination of the manganese product. The bubbles formed by argon in the molten pool have a good purifying effect; as the bubbles rise, they adsorb and carry gases and other non-metallic inclusions from the melt to the surface, achieving a "gas washing" effect.

[0046] Optionally, the first and second manganese ores have the same manganese grade, both greater than 45%.

[0047] In this application, the reaction of silicon-reduced manganese ore exhibits a high reaction rate constant above 1600℃. For every 100℃ increase in temperature, the reaction rate constant increases by approximately 2 to 3 times. Raising the endpoint temperature to above 1600℃ ensures that unreacted MnO is fully reduced in the final stage. Furthermore, the CaO-SiO2-MnO slag exhibits good fluidity in the 1600-1650℃ temperature range, which is beneficial for slag-gold separation and slag removal operations. Below 1600℃, if the slag basicity is high (e.g., >2.0), the slag viscosity may increase sharply, leading to difficulties in slag-gold separation; above 1650℃, the erosion rate of the slag on the furnace lining refractory material accelerates significantly, affecting the furnace life.

[0048] Optionally, the manganese content in the ferrosilicon alloy molten iron is greater than 65%, and the silicon content is greater than 28%.

[0049] In this application, high-grade manganese ore with a grade greater than 45% is selected, which has a relatively low impurity content (mainly SiO2, Al2O3, Fe2O3, etc.). Silicon is used as a reducing agent in this application. While reducing MnO, silicon also reduces FeO in the manganese ore to produce iron, which ultimately enters the metallic manganese product. If the manganese ore grade is lower than 45%, it means a higher impurity content, with harmful elements such as iron and phosphorus entering the metallic manganese during the reduction process, reducing product purity and increasing the burden on subsequent refining. Moreover, the reduction reaction of higher-grade manganese ore is more vigorous, releasing more heat; while lower-grade manganese ore absorbs more heat, leading to more pronounced fluctuations in the molten pool temperature. Using manganese ore of the same grade is beneficial for stabilizing process parameters and achieving standardized process control.

[0050] Secondly, this application provides a metallic manganese, including manganese obtained by the smelting method described in the first aspect above.

[0051] The manganese metal of this application, through silicothermic reduction reaction and control of slag basicity, can have its impurities such as iron, phosphorus, and sulfur kept at low levels, with the product's manganese metal content reaching over 96%. The use of argon stirring and static slag removal processes effectively removes non-metallic inclusions from the molten metal, improving product purity. Specific Implementation In the following examples, the first and second manganese ores have the same manganese grade, both greater than 45%; the ferrosilicon alloy molten iron has a manganese content greater than 65% and a silicon content greater than 28%.

[0053] Example 1 S101. Mix 367 kg of first manganese ore and 300 kg of first lime and add them to the smelting furnace. Then add 1000 kg of molten silicon-manganese alloy iron at 1500°C to the furnace.

[0054] S102. Open the spray gun at the top of the smelting furnace to inject oxygen into the furnace, and at the same time open the spray gun on the lower side of the smelting furnace to inject argon into the furnace. During the injection process, add a total of 734 kg of second manganese ore and 300 kg of second lime according to the following procedure: The second batch of manganese ore was divided into multiple batches of 100kg / batch, with the last batch containing less than 100kg being recorded as the final batch. Oxygen and inert gas are injected until the molten pool temperature reaches the initial temperature of the silicon-manganese alloy molten iron, denoted as T (T=1500℃). For every 100kg of second manganese ore added, the mixture is smelted until the molten pool temperature equals T±10℃ before adding the next batch of second manganese ore, until the last batch is completed. The second lime is added as follows: for every 100kg of second manganese ore added, 60kg of second lime is added, until all the second lime is used.

[0055] After the S103 and second manganese ore are fed, continue to inject oxygen and argon until the temperature of the molten pool reaches 1600℃, then continue to inject for 15 minutes, stop injecting oxygen, and continue to inject argon until the silicon content in the molten pool meets the standard. S104. The melt is transferred into a ladle, allowed to stand for 5 minutes, then slag is removed, and the mixture is cast and cooled to obtain metallic manganese.

[0056] In the above process, the argon gas injection pressure is 1.2 MPa and the injection rate is 70 Nm³. 3 / t iron; The oxygen injection pressure is 1.2 MPa, and the injection rate is 70 Nm³. 3 / t iron.

[0057] Example 2 S201. Mix 260 kg of first manganese ore and 267 kg of first lime and add them to the smelting furnace. Then add 1000 kg of molten silicon-manganese alloy iron at 1550°C to the furnace.

[0058] S202. Open the spray gun at the top of the smelting furnace to inject oxygen into the furnace, and at the same time open the spray gun on the lower side of the smelting furnace to inject argon into the furnace. During the injection process, add a total of 1040 kg of second manganese ore and 534 kg of second lime according to the following procedure: The second batch of manganese ore was divided into multiple batches of 100kg / batch, with the last batch containing less than 100kg being recorded as the final batch. Oxygen and inert gas are injected until the molten pool temperature reaches the initial temperature of the silicon-manganese alloy molten iron, denoted as T (T=1550℃). For every 100kg of second manganese ore added, the mixture is smelted until the molten pool temperature equals T±10℃ before adding the next batch of second manganese ore, until the last batch is completed. The second lime is added as follows: for every 100kg of second manganese ore added, 80kg of second lime is added, until all the second lime is used.

[0059] After S203 and the second manganese ore are fed, continue to inject oxygen and argon until the temperature of the molten pool reaches 1650℃, then continue to inject for 10 minutes, stop injecting oxygen, and continue to inject argon until the silicon content in the molten pool meets the standard. S204. The melt is transferred into a ladle, allowed to stand for 8 minutes, then slag is removed, and the mixture is cast and cooled to obtain metallic manganese.

[0060] In the above process, the argon gas injection pressure was 2.4 MPa and the injection rate was 90 Nm³. 3 / t iron; The oxygen injection pressure is 2.4 MPa, and the injection rate is 90 Nm³. 3 / t iron.

[0061] Example 3 S301. Mix 300 kg of first manganese ore and 280 kg of first lime and add them to the smelting furnace. Then add 1000 kg of molten silicon-manganese alloy iron at 1530°C to the furnace.

[0062] S302. Open the spray gun at the top of the smelting furnace to inject oxygen into the furnace, and at the same time open the spray gun on the lower side of the smelting furnace to inject argon into the furnace. During the injection process, add a total of 900 kg of second manganese ore and 420 kg of second lime according to the following procedure: The second batch of manganese ore was divided into multiple batches of 100kg / batch, with the last batch containing less than 100kg being recorded as the final batch. Oxygen and inert gas are injected until the molten pool temperature reaches the initial temperature of the silicon-manganese alloy molten iron, denoted as T (T=1530℃). For every 100kg of second manganese ore added, the mixture is smelted until the molten pool temperature equals T±10℃ before adding the next batch of second manganese ore, until the last batch is completed. The addition of the second lime is as follows: for every 100kg of second manganese ore added, 70kg of second lime is added, until the second lime is completely added.

[0063] After S303 and the second manganese ore are fed, continue to inject oxygen and argon until the temperature of the molten pool reaches 1600~1650℃, then continue to inject for 13 minutes, stop injecting oxygen, and continue to inject argon until the silicon content in the molten pool meets the standard. S304. The melt is transferred into a ladle, allowed to stand for 7 minutes, then slag is removed, and the mixture is cast and cooled to obtain metallic manganese.

[0064] In the above process, the argon gas injection pressure is 1.8 MPa and the injection rate is 80 Nm³. 3 / t iron; The oxygen injection pressure is 1.8 MPa, and the injection rate is 80 Nm³. 3 / t iron.

[0065] A ferrosilicon-manganese alloy (Mn: 66.7%, Si: 28.6%, Fe: 2.2%) and manganese ore (Mn grade: 46.7%, Fe: 4.1%) were selected. The above method was used for smelting to produce metallic manganese. The composition of the obtained metallic manganese is shown in Table 1. Table 1

[0066] As can be seen from the data in Table 1, in terms of the quality of the smelted products, the smelting of metallic manganese using the method of this application, which employs oxygen top blowing and argon side blowing, yields metallic manganese products with a content of over 96%, and the contents of carbon, silicon, iron, sulfur, and phosphorus can be controlled to extremely low values, meeting the corresponding smelting requirements.

[0067] Regarding energy conservation, for producing metallic manganese of the same specifications using the same raw materials, the energy consumption of the method in this application compared to the traditional silicothermic method is estimated as follows: Taking the production of 1 ton of metallic manganese as an example: Silicon-manganese alloy (Mn 65%, Si 28%): 866 kg; Manganese ore (Mn grade >45%): 1039 kg; Quicklime (CaO): 606 kg.

[0068] The energy consumption of the traditional silicon thermal method is shown in Table 2: Table 2

[0069] Equivalent electrical energy (1 kWh = 3600 kJ): 3.918 × 10 6 / 3600≈1088kWh.

[0070] Considering the thermal efficiency of the electric furnace (usually 70%~80%), the actual power consumption is 1360~1554kWh.

[0071] Because the proposed method only injects oxygen and argon during the smelting process, its energy consumption is negligible. Therefore, theoretically, the proposed method can save 1360~1554 kWh of electricity compared to the traditional silicothermic method.

[0072] In actual production, the method described in this application saves approximately 1330 kWh of electricity.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for smelting metallic manganese, characterized in that, Includes the following steps: The first manganese ore and the first lime were mixed and added to the smelting furnace, and molten silicon-manganese alloy iron was added to the furnace. Turn on the spray gun at the top of the smelting furnace to inject oxygen into the furnace, and at the same time turn on the spray gun on the lower side of the smelting furnace to inject inert gas into the furnace. During the injection process, add the second manganese ore and the second lime according to the second manganese ore feeding system. After the second manganese ore is fed, continue to inject oxygen and inert gas until the molten pool temperature reaches the preset temperature, then continue to inject for another 10-15 minutes, stop injecting oxygen, and continue to inject inert gas until the silicon content in the molten pool reaches the standard. The molten material is transferred into a ladle, allowed to stand, slag is removed, and the material is cast and cooled to obtain metallic manganese. The second manganese ore feeding system is as follows: The second batch of manganese ore was divided into multiple batches of 100kg / batch, with the last batch containing less than 100kg being recorded as the final batch. Oxygen and inert gas are injected until the temperature of the molten pool reaches the initial temperature at which the silicon-manganese alloy molten iron is added, denoted as T; For every 100 kg of the second manganese ore added, the molten pool temperature is blown up to T ± 10℃ before adding the next batch of the second manganese ore, until the last batch of the second manganese ore is added. The procedure for adding the second lime is as follows: When adding 100 kg of second manganese ore, add 60-80 kg of second lime, until the second lime is completely added; The weight ratio of the first manganese ore to the second manganese ore is 1:(2~4), and the weight ratio of the first limestone to the second limestone is 1:(1~2). The ratio of the total weight of the first and second manganese ores to the weight of the molten ferrosilicon (1.1~1.3):1; The total weight ratio of the first and second limes to the molten silicon-manganese alloy is (0.6~0.8):

1.

2. The method for smelting metallic manganese according to claim 1, characterized in that, The temperature of the molten silicon-manganese alloy is 1500~1550℃.

3. The method for smelting metallic manganese according to claim 1, characterized in that, The inert gas is injected at a pressure of 1.2~2.4 MPa and at a rate of 70~90 Nm³. 3 / t iron; The oxygen injection pressure is 1.2~2.4 MPa, and the injection rate is 70~90 Nm³. 3 / t iron.

4. The method for smelting metallic manganese according to claim 1, characterized in that, The melt is transferred into a ladle and left to stand for 5-8 minutes.

5. The method for smelting metallic manganese according to claim 1, characterized in that, The inert gas is argon; The preset temperature is 1600~1650℃.

6. The method for smelting metallic manganese according to claim 1, characterized in that, The first and second manganese ores have the same manganese grade, both greater than 45%.

7. The method for smelting metallic manganese according to claim 1, characterized in that, The ferrosilicon alloy molten iron contains more than 65% manganese and more than 28% silicon.

8. A type of metallic manganese, characterized in that, Including those obtained by smelting by any one of the smelting methods described in claims 1 to 7.

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