Smelting method of low phosphorus silicon-manganese alloy

Abstract

This application provides a method for smelting a low-phosphorus silicon-manganese alloy, comprising: obtaining raw materials for smelting the low-phosphorus silicon-manganese alloy and pretreating the raw materials to obtain smelting raw materials; adding the smelting raw materials to an electric furnace for smelting to obtain a first low-phosphorus silicon-manganese alloy liquid; transferring the first low-phosphorus silicon-manganese alloy liquid to a shaking ladle and reacting for a first preset time to obtain a second low-phosphorus silicon-manganese alloy liquid; transferring the second low-phosphorus silicon-manganese alloy liquid to a ladle, spraying a first dephosphorizing agent into the ladle for a second preset time, allowing it to stand for a third preset time, and then removing slag to obtain a third low-phosphorus silicon-manganese alloy liquid; pouring the third low-phosphorus silicon-manganese alloy liquid into a mold to cast an ingot, and demolding it after cooling to obtain the finished low-phosphorus silicon-manganese alloy. This application, through pretreatment, shaking ladle operation, and spraying of the first dephosphorizing agent, reduces the phosphorus content and impurities in the finished low-phosphorus silicon-manganese alloy, thereby improving the purity of the finished low-phosphorus silicon-manganese alloy.

Description

Technical Field

[0001] This application relates to the field of smelting technology of silicon-manganese alloys, and in particular to a smelting method for low-phosphorus silicon-manganese alloys. Background Technology

[0002] Manganese-silicon alloys are indispensable alloys in the iron and steel metallurgical industry. They serve as deoxidizers in the steelmaking process and are also important alloying element additives. Phosphorus (P) in these alloys, as a harmful impurity element, can worsen the plasticity and toughness (cold brittleness) of steel and affect its weldability. Therefore, controlling the phosphorus content in manganese-silicon alloys is of great significance.

[0003] Traditional smelting methods for manganese-silicon alloys typically employ submerged arc furnaces. This method uses manganese ore, silica, and coke as main raw materials, employing reduction smelting through the heat generated by an electric arc and resistance heat produced when electrodes are embedded in the furnace charge. However, the manganese ore and silica used in smelting, especially the coke used as a reducing agent, often contain a certain amount of phosphorus. Phosphorus exists in these raw materials in the form of phosphates or elemental forms. Phosphate rock (when used as an additive), certain rich manganese ores, and high-phosphorus coke from certain regions are the main phosphorus sources, and phosphorus impurities in the raw materials are a key factor limiting the phosphorus content of the final product. Based on this, this application proposes a smelting method for low-phosphorus ferrosilicon manganese alloys. Summary of the Invention

[0004] This application provides a method for smelting a low-phosphorus silicon-manganese alloy to solve the technical problems described in the background section.

[0005] To solve the above-mentioned technical problems, this application adopts the following technical solution: This application provides a method for smelting a low-phosphorus silicon-manganese alloy, comprising: Obtain raw materials for smelting low-phosphorus silicon-manganese alloy and pretreat the raw materials to obtain smelting raw materials; The raw materials are added to an electric furnace for smelting to obtain a first low-phosphorus silicon-manganese alloy liquid. The first low-phosphorus silicon-manganese alloy liquid is transferred to a shaker and reacted for a first preset time to obtain a second low-phosphorus silicon-manganese alloy liquid. The second low-phosphorus silicon-manganese alloy liquid is transferred to a ladle, and the first dephosphorizing agent is sprayed into the ladle for a second preset time. After standing for a third preset time, the slag is removed to obtain the third low-phosphorus silicon-manganese alloy liquid. The third low-phosphorus silicon-manganese alloy liquid is poured into a mold to cast an ingot, and after cooling, it is demolded to obtain the finished low-phosphorus silicon-manganese alloy.

[0006] Optionally, obtaining the raw materials for smelting low-phosphorus silicon-manganese alloy and pretreating the raw materials includes the following steps: The raw material is crushed and sieved to obtain a raw material with a first particle size; Add binder and water to the raw materials and mix thoroughly to obtain a mixture; The mixture is pressed into spherical particles of the second particle size to obtain the smelting raw material; The amount of adhesive and water added to the mixture is 1%-5% of the mass of the raw materials, and the mass ratio of water added to the raw materials is (20:1)-(35:1).

[0007] Optionally, the first particle size is ≤60mm; The second particle size is 80mm-100mm.

[0008] Optionally, the raw materials include 950-1050 parts by weight of manganese ore, 200-300 parts by weight of silica, 210-310 parts by weight of coke, and 30-150 parts by weight of a second dephosphorizing agent.

[0009] Optionally, the manganese ore has a manganese content >30%, Mn / Fe >4.5, P / Mn ≤0.0035, and its particle size is 10mm-60mm; The silica contains more than 98% SiO2 by mass and has a particle size of 10mm-20mm. The coke has a fixed carbon content of >84%, an ash content of <15%, and a particle size of 3mm-25mm. The second dephosphorizing agent is any one of CaO, CaF2, CaSi, or CaO-CaF2-CaSi.

[0010] Optionally, when the raw materials are added to the electric furnace for smelting, the power supply system in the electric furnace is alternating current or direct current; When the power supply system in the electric furnace is AC, the voltage is 280V-320V and the current is 38000A-42000A; When the power supply system in the electric furnace is DC, the voltage is 180V-220V and the current is 38000A-42000A.

[0011] Optionally, the first preset time is 5 min-15 min, and the rotation speed of the bag shaking is 40 r / min-55 r / min.

[0012] Optionally, the first dephosphorizing agent is either rare earth powder or Ca-Mg composite powder.

[0013] Optionally, the second preset time is 8 min-30 min; The injection rate of the first dephosphorizing agent is 0.3 m. 3 / h-0.6m 3 / h, and its blowing pressure is 0.2 MPa - 0.5 MPa; The third preset time is 20-25 minutes.

[0014] Optionally, at the start of the settling process: inert gas for a fourth preset time is introduced into the ladle and stirred; The fourth preset time is 6-8 minutes.

[0015] The smelting method for low-phosphorus ferrosilicon manganese alloy provided in this application involves pre-treating the raw materials used for smelting the low-phosphorus ferrosilicon manganese alloy to ensure more uniform mixing. The resulting first low-phosphorus ferrosilicon manganese alloy liquid is then transferred to a shaking ladle and reacted for a first preset time to obtain a second low-phosphorus ferrosilicon manganese alloy liquid. The shaking ladle, through the movement of an eccentric shaft, causes the first low-phosphorus ferrosilicon manganese alloy liquid to churn in a "wave-like" manner, increasing the slag-metal contact area, accelerating the mass transfer process, and shortening the reaction time. Furthermore, the aforementioned "wave-like" motion effectively disrupts the slag-iron interface, promoting slag-iron separation and reducing the amount of phosphorus in the second low-phosphorus ferrosilicon manganese alloy liquid. The presence of metallic inclusions in the second low-phosphorus ferrosilicon manganese alloy liquid results in higher purity. The liquid is then transferred to a ladle, and a first dephosphorizing agent is sprayed into the ladle for a second preset time. After standing for a third preset time, slag is removed. The spraying of the first dephosphorizing agent causes a chemical reaction between the active components in the agent and the phosphorus in the second low-phosphorus ferrosilicon manganese alloy liquid, converting the phosphorus into a stable compound and transferring it to the slag phase. This reduces the phosphorus content in the resulting third low-phosphorus ferrosilicon manganese alloy liquid. Finally, the third low-phosphorus ferrosilicon manganese alloy liquid is poured into a mold to form an ingot. After cooling, it is demolded to obtain the finished low-phosphorus ferrosilicon manganese alloy. This application reduces the phosphorus content and impurities in the finished low-phosphorus ferrosilicon manganese alloy by pretreatment, ladle shaking, and the spraying of the first dephosphorizing agent, thereby improving the purity of the finished low-phosphorus ferrosilicon manganese alloy. Detailed Implementation

[0016] 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.

[0017] This application provides a method for smelting a low-phosphorus silicon-manganese alloy, comprising: Raw materials for smelting low-phosphorus silicon-manganese alloy are obtained and pretreated to obtain smelting raw materials. The purpose of pretreatment is to improve the uniformity of the raw materials after mixing, so that the smelting raw materials are more uniform and conducive to subsequent smelting.

[0018] The raw materials are added to an electric furnace for smelting to obtain a first low-phosphorus silicon-manganese alloy liquid; the raw materials are melted under high temperature conditions in the electric furnace to obtain the first low-phosphorus silicon-manganese alloy liquid.

[0019] The first low-phosphorus silicon-manganese alloy liquid is transferred to a shaker and reacted for a first preset time to obtain the second low-phosphorus silicon-manganese alloy liquid. The shaker, through the movement of the eccentric shaft, causes the first low-phosphorus silicon-manganese alloy liquid to churn in a "wave-like" manner, increasing the slag-metal contact area, accelerating the mass transfer process, and shortening the reaction time. Moreover, the "wave-like" manner can effectively disrupt the slag-iron interface, promote slag-iron separation, reduce metal inclusions in the second low-phosphorus silicon-manganese alloy liquid, and make the second low-phosphorus silicon-manganese alloy liquid have higher purity.

[0020] The second low-phosphorus silicon-manganese alloy liquid is transferred to a ladle, and the first dephosphorizing agent is sprayed into the ladle for a second preset time. After standing for a third preset time, the slag is removed to obtain the third low-phosphorus silicon-manganese alloy liquid. The spraying of the first dephosphorizing agent causes the active components in the dephosphorizing agent to react chemically with the phosphorus in the second low-phosphorus silicon-manganese alloy liquid, converting the phosphorus into a stable compound and transferring it to the slag phase, thereby reducing the phosphorus content in the obtained third low-phosphorus silicon-manganese alloy liquid.

[0021] The third low-phosphorus silicon-manganese alloy liquid is poured into a mold to cast an ingot. After cooling, it is demolded to obtain the finished low-phosphorus silicon-manganese alloy.

[0022] The smelting method for low-phosphorus ferrosilicon manganese alloy provided in this application involves pre-treating the raw materials used for smelting the low-phosphorus ferrosilicon manganese alloy to ensure more uniform mixing. The resulting first low-phosphorus ferrosilicon manganese alloy liquid is then transferred to a shaking ladle and reacted for a first preset time to obtain a second low-phosphorus ferrosilicon manganese alloy liquid. The shaking ladle, through the movement of an eccentric shaft, causes the first low-phosphorus ferrosilicon manganese alloy liquid to churn in a "wave-like" manner, increasing the slag-metal contact area, accelerating the mass transfer process, and shortening the reaction time. Furthermore, the aforementioned "wave-like" motion effectively disrupts the slag-iron interface, promoting slag-iron separation and reducing the amount of phosphorus in the second low-phosphorus ferrosilicon manganese alloy liquid. The presence of metallic inclusions in the second low-phosphorus ferrosilicon manganese alloy liquid results in higher purity. The liquid is then transferred to a ladle, and a first dephosphorizing agent is sprayed into the ladle for a second preset time. After standing for a third preset time, slag is removed. The spraying of the first dephosphorizing agent causes a chemical reaction between the active components in the agent and the phosphorus in the second low-phosphorus ferrosilicon manganese alloy liquid, converting the phosphorus into a stable compound and transferring it to the slag phase. This reduces the phosphorus content in the resulting third low-phosphorus ferrosilicon manganese alloy liquid. Finally, the third low-phosphorus ferrosilicon manganese alloy liquid is poured into a mold to form an ingot. After cooling, it is demolded to obtain the finished low-phosphorus ferrosilicon manganese alloy. This application reduces the phosphorus content and impurities in the finished low-phosphorus ferrosilicon manganese alloy by pretreatment, ladle shaking, and the spraying of the first dephosphorizing agent, thereby improving the purity of the finished low-phosphorus ferrosilicon manganese alloy.

[0023] In some embodiments, the acquisition of raw materials for smelting low-phosphorus silicon-manganese alloys and the pretreatment of the raw materials in this application include the following steps: The raw materials are crushed and sieved to obtain raw materials with a first particle size; the purpose of crushing is to obtain raw materials with a smaller particle size, so as to increase the contact area of ​​the raw materials and make the subsequent mixing of raw materials more uniform.

[0024] A binder and water are added to the raw materials and mixed evenly to obtain a mixture; wherein the binder can be pregelatinized starch, polymer, etc., and this application does not specifically limit it.

[0025] The mixture is pressed into spherical particles of the second particle size to obtain smelting raw materials; wherein the amount of binder added to the mixture is 1%-5% of the raw material mass, and the ratio of the amount of water added to the raw material mass is (20:1)-(35:1).

[0026] In the above embodiments, by crushing and screening the raw materials to obtain the first particle size, the mixing process of the raw materials becomes more uniform. The spherical particles of the second particle size obtained by pressing are spherical particles after the raw materials are evenly mixed, and they are added to the electric furnace for smelting. The amount of the binder added is 1%-5% of the mass of the raw materials, and the ratio of water added to the mass of the raw materials in the mixture is (20:1)-(35:1). This makes the spherical particles of the second particle size more uniform and easier to smelt.

[0027] In some embodiments, the first particle size in this application is ≤60mm, which avoids the particle size of the raw material after crushing and screening being too large, and makes the particle size of the screened raw material more uniform.

[0028] In addition, the second particle size is 80mm-100mm, and the particle size of the spherical particles is all between 80mm and 100mm. During the smelting process, the particle size of the spherical particles is as uniform as possible, so that the melting rate of each spherical particle is as consistent as possible, thereby improving the smelting efficiency.

[0029] In some embodiments, the raw materials in this application include 950-1050 parts by weight of manganese ore, 200-300 parts by weight of silica, 210-310 parts by weight of coke, and 30-150 parts by weight of a second dephosphorizing agent.

[0030] In the above embodiments, in addition to manganese ore, silica, and coke, a second dephosphorizing agent is added. Specifically, manganese ore, as the main source of manganese in the low-phosphorus silicomanganese alloy, is mainly composed of manganese oxides (such as MnO2, Mn2O3, etc.), which are reduced to metallic manganese at high temperatures and enter the alloy. Silica, as the main source of silicon in the alloy, is mainly composed of silicon dioxide (SiO2), which is reduced to silicon by carbon at high temperatures and combines with manganese to form a silicomanganese alloy. Here, coke acts as a reducing agent and a heating agent. The fixed carbon in the coke reduces the oxides of manganese and silicon at high temperatures, and provides the required high temperature for the entire smelting process through resistance heating and chemical reaction heat. The addition of the second dephosphorizing agent allows it to react with phosphorus in the alloy under reducing conditions, generating stable, insoluble alkaline earth metal phosphides, thereby fixing the phosphorus to the slag and removing it, thus reducing the phosphorus content in the finished low-phosphorus silicomanganese alloy.

[0031] In some embodiments, the manganese ore in this application has a manganese content >30%, Mn / Fe >4.5, P / Mn ≤0.0035, and a particle size of 10mm-60mm. The manganese content >30% directly increases the manganese grade of the raw material, meaning that with the same feed amount, more metallic manganese can be produced, significantly improving manganese recovery, reducing unit power consumption, and decreasing slag volume. Mn / Fe >4.5 ensures a high manganese-to-iron ratio in the manganese ore, which effectively controls the iron content in the alloy, preventing excessive iron from diluting the manganese concentration and resulting in a higher manganese content in the low-phosphorus ferrosilicon alloy product. However, a high iron-to-iron ratio in the raw material increases iron loss in the slag, reducing manganese recovery. During the smelting process, phosphorus is extremely difficult to remove, and P / Mn ≤0.0035 aims to strictly limit phosphorus input at the source. Furthermore, a manganese ore particle size between 10mm and 60mm helps maintain good permeability of the furnace charge, preventing excessively fine powder from causing crusting and reduced permeability, and also preventing incomplete reaction and uneven melting of excessively large pieces. The silica contains more than 98% SiO2 by mass, with a particle size of 10mm-20mm. The SiO2 content >98% provides a highly efficient and pure silicon source, while the high SiO2 content means minimal introduced impurities (such as Al2O3 and P2O5), which helps reduce slag volume and viscosity, and prevents impurity elements (especially phosphorus) from entering the alloy. A silica particle size between 10mm and 20mm facilitates sufficient contact and uniform reaction with coke and manganese ore particles. Particles that are too small are easily carried away by the airflow or cause sintering of the furnace charge; particles that are too large result in slow reduction rates and are prone to abnormal furnace conditions such as "silica flotation."

[0032] The coke contains >84% fixed carbon and <15% ash, with a particle size of 3mm-25mm. The high fixed carbon content ensures the coke can function as a powerful reducing agent and exothermic agent. The ash, primarily composed of inert substances such as SiO2 and Al2O3, does not participate in the reduction reaction. The low ash content reduces the introduction of ineffective slag-forming substances, which is beneficial for controlling slag volume, stabilizing slag composition, and improving reaction efficiency. The coke particle size of 3mm-25mm ensures uniform current flow through the material layer, concentrating and stabilizing the reaction zone (crucible) and preventing "sparking" or electrode lifting.

[0033] In addition, the second dephosphorizing agent is any one of CaO, CaF2, CaSi, or CaO-CaF2-CaSi.

[0034] In the above embodiments, CaO is the main basic oxide, providing O. 2- Combined with phosphorus. CaF2 (fluorite): As a flux, it can significantly reduce the melting point and viscosity of dephosphorized slag, improve its fluidity, and make the slag-metal reaction more complete and rapid. CaSi (calcium silicon) is both a dephosphorizing agent, a powerful reducing agent, and an alloying element. It not only promotes the dephosphorization reaction, but its silicon content can also supplement the silicon content of the alloy and enhance the deoxidation effect. Under reducing conditions, the above-mentioned alkaline components can react with phosphorus (such as [MnP]) in the alloy to generate stable alkaline earth metal phosphides such as Ca3P2, which are insoluble in the alloy, thereby fixing the phosphorus in the slag for removal.

[0035] In some embodiments, when raw materials are added to an electric furnace for smelting, the power supply system in the electric furnace is alternating current or direct current; wherein, alternating current or direct current can be selected according to the actual situation, and this application does not specifically limit it.

[0036] When the electric furnace is powered by alternating current (AC), the voltage is 280V-320V and the current is 38000A-42000A. The AC system (high voltage) focuses on utilizing mature technology to achieve a stable and controllable high-temperature reaction environment through the matching of high voltage and high current, ensuring smooth production and electrode safety. When the electric furnace is powered by direct current (DC), the voltage is 180V-220V and the current is 38000A-42000A. The DC system (low voltage) represents a more advanced technological direction. Its core advantages of low voltage and high current lie in extremely high energy utilization efficiency and extremely low electrode consumption, making it a key technological transformation path for achieving deep energy conservation and consumption reduction.

[0037] In the above embodiments, regardless of whether an AC or DC system is used, maintaining a high current level of 38000A-42000A aims to: 1) provide sufficient reduction power: a large current is fundamental to generating a high-temperature electric arc and strong resistance heat, ensuring that the furnace can reach a high temperature of over 1800℃, satisfying the thermodynamic conditions for the reduction of difficult-to-reduce oxides such as SiO2 by carbon; 2) achieve high power factor operation: reasonable matching of current and voltage aims to make the electric furnace operate in the optimal power range close to its rated capacity, avoiding overload, thereby achieving high output and low consumption. In some embodiments, the first preset time in this application is 5min-15min, and the shaking speed is 40r / min-55r / min.

[0038] In the above embodiments, when the shaking speed of the first low-phosphorus silicon-manganese alloy liquid is 40 r / min-55 r / min, the reaction time of 5 min-15 min can cause the first low-phosphorus silicon-manganese alloy liquid to produce a "wave-like" turbulence, which increases the slag-metal contact area, accelerates the mass transfer process, and shortens the reaction time. Moreover, the "wave-like" turbulence can effectively destroy the slag-iron interface, promote slag-iron separation, reduce metal inclusions in the second low-phosphorus silicon-manganese alloy liquid, and make the purity of the second low-phosphorus silicon-manganese alloy liquid higher.

[0039] In some embodiments, the first dephosphorizing agent in this application is either rare earth powder or Ca-Mg composite powder.

[0040] In the above embodiments, the shaking bag generates a strong stirring effect through rotation, which significantly expands the reaction interface between the first dephosphorizing agent and the alloy liquid, and accelerates the flotation and separation of the reaction products. When the first dephosphorizing agent is rare earth powder, due to the extremely active chemical properties of rare earth powder (such as Ce, La, etc.), it has a strong deoxidizing, desulfurizing, and dephosphorizing ability. Furthermore, rare earth powder has a very strong affinity for phosphorus, which can generate stable rare earth phosphides (such as CeP, LaP). These compounds are insoluble in the alloy liquid and have a low density, making them easy to float into the slag phase, thereby achieving deep dephosphorization. Simultaneously, rare earth can also effectively remove impurities such as oxygen and sulfur from the alloy, playing a comprehensive purification role. Furthermore, when the first dephosphorizing agent is Ca-Mg composite powder, the combination of calcium and magnesium, both potent deoxidizers and dephosphorizers, produces a synergistic effect. Specifically, calcium reacts with phosphorus to form highly stable Ca3P2, which is the core reaction for dephosphorization of alkaline slag. The addition of magnesium not only participates in dephosphorization (generating Mg3P2) but also significantly reduces the melting point and viscosity of the dephosphorized slag system, improves slag fluidity, and makes the reaction more complete, resulting in easier separation of dephosphorization products. Simultaneously, Ca and Mg are also strong desulfurizers, enabling simultaneous desulfurization. They have a strong affinity for oxygen, significantly reducing the dissolved oxygen content in the alloy and creating a stronger reducing atmosphere for the dephosphorization reaction (since dephosphorization of silicon-manganese alloys requires reducing conditions).

[0041] In some embodiments, the second preset time in this application is 8 min-30 min; spraying the first dephosphorizing agent into the ladle for 8 min-30 min enables the first dephosphorizing agent to fully act on the second low-phosphorus silicon-manganese alloy liquid, thereby effectively destroying the slag-iron interface, promoting slag-iron separation, reducing metal inclusions in the second low-phosphorus silicon-manganese alloy liquid, and making the obtained third low-phosphorus silicon-manganese alloy liquid have higher purity.

[0042] In addition, the injection rate of the first dephosphorizing agent is 0.3 m. 3 / h-0.6m 3 The first dephosphorizing agent can be fully and quickly dispersed in the second low-phosphorus silicon-manganese alloy liquid at a blowing rate of 0.2 MPa - 0.5 MPa and a blowing pressure of 0.2 MPa - 0.5 MPa. The blowing rate and pressure of the first dephosphorizing agent cause the active components in the dephosphorizing agent to react chemically with the phosphorus in the second low-phosphorus silicon-manganese alloy liquid, converting the phosphorus into a stable compound and transferring it to the slag phase, thereby reducing the phosphorus content in the obtained third low-phosphorus silicon-manganese alloy liquid.

[0043] In addition, the third preset time is 20min-25min. This time ensures that the impurities in the second low-phosphorus silicon-manganese alloy liquid are fully floated to the surface of the alloy liquid, and then the impurity content in the third low-phosphorus silicon-manganese alloy liquid is reduced by slag removal.

[0044] In some embodiments, at the start of the settling process in this application: an inert gas for a fourth preset time is introduced into the ladle and stirred; wherein, by introducing an inert gas (such as argon), air is forced out of the ladle, forming an oxygen-free or low-oxygen protective environment, thereby effectively preventing oxidation of the third low-phosphorus ferrosilicon alloy liquid during the settling period due to contact with air, ensuring the stability of each component in the low-phosphorus ferrosilicon alloy product. In addition, the inert gas generates bubbles to provide buoyancy for impurities in the third low-phosphorus ferrosilicon alloy liquid to rise, carrying non-metallic inclusions (such as oxides trapped in the alloy) to the surface of the third low-phosphorus ferrosilicon alloy liquid, forming slag and discharging it from the ladle, thereby improving the purity of the low-phosphorus ferrosilicon alloy product.

[0045] In addition, the fourth preset time is 6-8 minutes. This time ensures that the impurities in the third low-phosphorus silicon-manganese alloy liquid are fully floated to the surface of the alloy liquid, thereby reducing the impurity content in the finished low-phosphorus silicon-manganese alloy.

[0046] The present invention will be further described in detail below with reference to embodiments. However, it should be understood that the embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0047] Example 1

[0048] The smelting method for low-phosphorus silicon-manganese alloy in this embodiment includes the following steps: S101. Obtain 950 parts by weight of manganese ore, 200 parts by weight of silica, 210 parts by weight of coke and 30 parts by weight of second dephosphorizing agent, and pretreat the above raw materials to obtain smelting raw materials. Among them, the manganese ore has a manganese content >30%, Mn / Fe >4.5, P / Mn ≤0.0035, and its particle size is 40mm; the silica has a SiO2 mass content >98%, and its particle size is 20mm; the coke has a fixed carbon content >84%, ash content <15%, and its particle size is 15mm; the second dephosphorizing agent is CaF2.

[0049] Preprocessing includes the following steps: S1011. The raw materials are crushed and sieved to obtain raw materials with a particle size ≤60mm; S1012. Add a certain amount of adhesive and water to the raw materials and mix them evenly to obtain a mixture; S1013. The mixture is pressed into spherical particles with a particle size of 80 mm to obtain smelting raw materials; The amount of adhesive added to the mixture is 5% of the mass of the raw materials, and the ratio of the amount of water added to the mass of the raw materials is 20:1.

[0050] S102. The smelting raw materials are added to an electric furnace for smelting to obtain the first low-phosphorus silicon-manganese alloy liquid. When the electric furnace is powered by alternating current, the voltage is 280V and the current is 38000A.

[0051] S103. Transfer the first low-phosphorus silicon-manganese alloy liquid to a shaker and react for 15 minutes to obtain the second low-phosphorus silicon-manganese alloy liquid. S104. Transfer the second low-phosphorus silicon-manganese alloy liquid to a ladle, spray rare earth powder into the ladle for 30 minutes, let it stand for 20 minutes, and then remove the slag to obtain the third low-phosphorus silicon-manganese alloy liquid. At the beginning of the above-mentioned settling process: inert gas is introduced into the ladle for 6 minutes and stirred.

[0052] S105. The third low-phosphorus silicon-manganese alloy liquid is poured into the mold to cast an ingot. After cooling, it is demolded to obtain the finished low-phosphorus silicon-manganese alloy.

[0053] Example 2

[0054] The smelting method for low-phosphorus silicon-manganese alloy in this embodiment includes the following steps: S201. Obtain 1050 parts by weight of manganese ore, 300 parts by weight of silica, 310 parts by weight of coke and 150 parts by weight of second dephosphorizing agent, and pretreat the above raw materials to obtain smelting raw materials. Among them, the manganese ore has a manganese content >30%, Mn / Fe >4.5, P / Mn ≤0.0035, and its particle size is 40mm; the silica has a SiO2 mass content >98%, and its particle size is 20mm; the coke has a fixed carbon content >84%, ash content <15%, and its particle size is 15mm; the second dephosphorizing agent is CaO.

[0055] Preprocessing includes the following steps: S2011. The raw materials are crushed and sieved to obtain raw materials with a particle size ≤60mm; S2012. Add a certain amount of adhesive and water to the raw materials and mix them evenly to obtain a mixture; S2013. The mixture is pressed into spherical particles with a particle size of 80 mm to obtain smelting raw materials; The amount of adhesive added to the mixture is 5% of the mass of the raw materials, and the ratio of the amount of water added to the mass of the raw materials is 20:1.

[0056] S202. The smelting raw materials are added to an electric furnace for smelting to obtain the first low-phosphorus silicon-manganese alloy liquid. When the electric furnace is powered by alternating current, the voltage is 280V and the current is 38000A.

[0057] S203. The first low-phosphorus silicon-manganese alloy liquid is transferred to a shaker and reacted for 15 minutes to obtain the second low-phosphorus silicon-manganese alloy liquid. S204. The second low-phosphorus silicon-manganese alloy liquid is transferred to a ladle, and rare earth powder is sprayed into the ladle for 30 minutes. After standing for 20 minutes, the slag is removed to obtain the third low-phosphorus silicon-manganese alloy liquid. At the beginning of the above-mentioned settling process: inert gas is introduced into the ladle for 6 minutes and stirred.

[0058] S205. The third low-phosphorus silicon-manganese alloy liquid is poured into the mold to form an ingot. After cooling, it is demolded to obtain the finished low-phosphorus silicon-manganese alloy.

[0059] Example 3

[0060] The smelting method for low-phosphorus silicon-manganese alloy in this embodiment includes the following steps: S301. Obtain 1000 parts by weight of manganese ore, 270 parts by weight of silica, 250 parts by weight of coke and 130 parts by weight of second dephosphorizing agent, and pretreat the above raw materials to obtain smelting raw materials. Among them, the manganese ore has a manganese content >30%, Mn / Fe >4.5, P / Mn ≤0.0035, and its particle size is 40mm; the silica has a SiO2 mass content >98%, and its particle size is 20mm; the coke has a fixed carbon content >84%, ash content <15%, and its particle size is 15mm; the second dephosphorizing agent is CaO-CaF2-CaSi.

[0061] Preprocessing includes the following steps: S3011. The raw materials are crushed and sieved to obtain raw materials with a particle size ≤60mm; S3012. Add a certain amount of adhesive and water to the raw materials and mix them evenly to obtain a mixture; S3013. The mixture is pressed into spherical particles with a particle size of 80 mm to obtain smelting raw materials; The amount of adhesive added to the mixture is 5% of the mass of the raw materials, and the ratio of the amount of water added to the mass of the raw materials is 20:1.

[0062] S302. The smelting raw materials are added to an electric furnace for smelting to obtain the first low-phosphorus silicon-manganese alloy liquid. When the electric furnace is powered by alternating current, the voltage is 280V and the current is 38000A.

[0063] S303. The first low-phosphorus silicon-manganese alloy liquid is transferred to a shaker and reacted for 15 minutes to obtain the second low-phosphorus silicon-manganese alloy liquid. S304. Transfer the second low-phosphorus silicon-manganese alloy liquid to a ladle, and spray Ca-Mg composite powder into the ladle for 30 minutes. After standing for 20 minutes, remove the slag to obtain the third low-phosphorus silicon-manganese alloy liquid. At the beginning of the above-mentioned settling process: inert gas is introduced into the ladle for 6 minutes and stirred.

[0064] S305. The third low-phosphorus silicon-manganese alloy liquid is poured into the mold to cast an ingot. After cooling, it is demolded to obtain the finished low-phosphorus silicon-manganese alloy.

[0065] Comparative Example 1 The difference from Example 1 is that no second dephosphorizing agent was added in S101.

[0066] Comparative Example 2 The difference from Example 1 is that rare earth powder or Ca-Mg composite powder was not sprayed into the ladle in S104.

[0067] Comparative Example 3 The difference from Example 1 is that inert gas was not introduced into the ladle in S104.

[0068] The resistance (where resistance is the ratio of the voltage on the secondary side of the electric arc furnace transformer to the current of the electric arc furnace electrode), alkalinity (referring to "Chemical Analysis Methods for Granulated Blast Furnace Slag" (GB / T 27975-2011)), Mn content (referring to "Silicon Manganese Alloys" (GB / T 4008-2008)), Si content (referring to "Silicon Manganese Alloys" (GB / T 4008-2008)), and P content (referring to "Determination of Phosphorus Content in Ferromanganese, Silicon Manganese Alloys, Ferromanganese Nitride and Metallic Manganese by Molybdenum Blue Spectrophotometry and Alkali Titration Method" (GB / T5686.4-2008)) of the samples in Examples 1, 3, 2, 3, 4, and 5 were calculated. Three parallel experiments were conducted for each experimental group, and the average value was taken. The calculation results are shown in Table 1. Table 1 alkalinity P / % Mn+Si / % Example 1 0.65 0.24 92.16 Example 2 0.64 0.23 91.87 Example 3 0.64 0.25 92.32 Comparative Example 1 0.65 0.65 91.51 Comparative Example 2 0.63 0.73 91.43 Comparative Example 3 0.64 0.24 87.56 By comparing Comparative Examples 1 and 2 in Table 1 with Example 1, it can be seen that without the addition of the second dephosphorizing agent and the first dephosphorizing agent (rare earth powder or Ca-Mg composite powder), the final low-phosphorus ferrosilicon alloy product has a higher P content. Meanwhile, comparing the data from Examples 1, 2, and 3 shows that the addition of the second and first dephosphorizing agents reduces the P content in the low-phosphorus ferrosilicon alloy. Comparing Comparative Example 3 with Example 1 shows that the injection of inert gas effectively reduces the impurity content in the low-phosphorus ferrosilicon alloy, resulting in a higher silicon and manganese content, thereby improving the purity of the low-phosphorus ferrosilicon alloy product. Furthermore, comparing Examples 2 and 3 with Example 1 shows that, with minimal differences in the amount of the second dephosphorizing agent added and the process conditions during smelting, the phosphorus content of the resulting low-phosphorus ferrosilicon alloy products is reduced.

[0069] 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 a low-phosphorus silicon-manganese alloy, characterized in that, include: Obtain raw materials for smelting low-phosphorus silicon-manganese alloy and pretreat the raw materials to obtain smelting raw materials; The raw materials include 950-1050 parts by weight of manganese ore, 200-300 parts by weight of silica, 210-310 parts by weight of coke, and 30-150 parts by weight of a second dephosphorizing agent. The manganese ore has a manganese content >30%, Mn / Fe >4.5, P / Mn ≤0.0035, and its particle size is 10mm-60mm; The silica contains more than 98% SiO2 by mass and has a particle size of 10mm-20mm. The coke has a fixed carbon content of >84%, an ash content of <15%, and a particle size of 3mm-25mm. The second dephosphorizing agent is any one of CaO, CaF2, CaSi, or CaO-CaF2-CaSi; The raw materials are added to an electric furnace for smelting to obtain a first low-phosphorus silicon-manganese alloy liquid. The first low-phosphorus silicon-manganese alloy liquid is transferred to a shaker and reacted for a first preset time to obtain a second low-phosphorus silicon-manganese alloy liquid. The second low-phosphorus silicon-manganese alloy liquid is transferred to a ladle, and the first dephosphorizing agent is sprayed into the ladle for a second preset time. After standing for a third preset time, the slag is removed to obtain the third low-phosphorus silicon-manganese alloy liquid. The first dephosphorizing agent is either rare earth powder or Ca-Mg composite powder; The third low-phosphorus silicon-manganese alloy liquid is poured into a mold to cast an ingot, and after cooling, it is demolded to obtain the finished low-phosphorus silicon-manganese alloy.

2. The smelting method for low-phosphorus silicon-manganese alloy according to claim 1, characterized in that, The process of obtaining raw materials for smelting low-phosphorus silicon-manganese alloys and pretreating the raw materials includes the following steps: The raw material is crushed and sieved to obtain a raw material with a first particle size; Add binder and water to the raw materials and mix thoroughly to obtain a mixture; The mixture is pressed into spherical particles of the second particle size to obtain the smelting raw material; The amount of adhesive and water added to the mixture is 1%-5% of the mass of the raw materials, and the mass ratio of water added to the raw materials is (20:1)-(35:1).

3. The smelting method for low-phosphorus silicon-manganese alloy according to claim 2, characterized in that, The first particle size is ≤60mm; The second particle size is 80mm-100mm.

4. The smelting method for low-phosphorus silicon-manganese alloy according to claim 1, characterized in that, When the raw materials are added to an electric furnace for smelting, the power supply system in the electric furnace is alternating current or direct current. When the power supply system in the electric furnace is AC, the voltage is 280V-320V and the current is 38000A-42000A; When the power supply system in the electric furnace is DC, the voltage is 180V-220V and the current is 38000A-42000A.

5. The smelting method for low-phosphorus silicon-manganese alloy according to claim 1, characterized in that, The first preset time is 5 min-15 min, and the rotation speed of the bag shaking is 40 r / min-55 r / min.

6. The smelting method for low-phosphorus silicon-manganese alloy according to claim 1, characterized in that, The second preset time is 8 min-30 min; The injection rate of the first dephosphorizing agent is 0.3 m. 3 / h-0.6m 3 / h, and its blowing pressure is 0.2 MPa - 0.5 MPa; The third preset time is 20-25 minutes.

7. The smelting method for low-phosphorus silicon-manganese alloy according to claim 1, characterized in that, At the start of the settling process: inert gas for a fourth preset time is introduced into the ladle and stirred; The fourth preset time is 6-8 minutes.